Series comparison

-[Qemu-devel] [PULL 00/12] Block patches
+[PULL v2 00/28] Block patches
-The following changes since commit dac03af5d5482ec7ee9c23db467bb7230b33c0d9:
+The following changes since commit ac793156f650ae2d77834932d72224175ee69086:
-  Merge remote-tracking branch 'remotes/rth/tags/pull-axp-20190825' into staging (2019-08-27 10:00:51 +0100)
+  Merge remote-tracking branch 'remotes/pmaydell/tags/pull-target-arm-20201020-1' into staging (2020-10-20 21:11:35 +0100)
 are available in the Git repository at:
-  https://github.com/stefanha/qemu.git tags/block-pull-request
+  https://gitlab.com/stefanha/qemu.git tags/block-pull-request
-for you to fetch changes up to 5396234b96a2ac743f48644529771498e036e698:
+for you to fetch changes up to 32a3fd65e7e3551337fd26bfc0e2f899d70c028c:
-  block/qcow2: implement .bdrv_co_pwritev(_compressed)_part (2019-08-27 14:58:42 +0100)
+  iotests: add commit top->base cases to 274 (2020-10-22 09:55:39 +0100)
 ----------------------------------------------------------------
 Pull request
+v2:
+ * Fix format string issues on 32-bit hosts [Peter]
+ * Fix qemu-nbd.c CONFIG_POSIX ifdef issue [Eric]
+ * Fix missing eventfd.h header on macOS [Peter]
+ * Drop unreliable vhost-user-blk test (will send a new patch when ready) [Peter]
+This pull request contains the vhost-user-blk server by Coiby Xu along with my
+additions, block/nvme.c alignment and hardware error statistics by Philippe
+Mathieu-Daudé, and bdrv_co_block_status_above() fixes by Vladimir
+Sementsov-Ogievskiy.
 ----------------------------------------------------------------
-Vladimir Sementsov-Ogievskiy (12):
+Coiby Xu (6):
-  util/iov: introduce qemu_iovec_init_extended
+  libvhost-user: Allow vu_message_read to be replaced
-  util/iov: improve qemu_iovec_is_zero
+  libvhost-user: remove watch for kick_fd when de-initialize vu-dev
-  block/io: refactor padding
+  util/vhost-user-server: generic vhost user server
-  block: define .*_part io handlers in BlockDriver
+  block: move logical block size check function to a common utility
-  block/io: bdrv_co_do_copy_on_readv: use and support qiov_offset
+    function
-  block/io: bdrv_co_do_copy_on_readv: lazy allocation
+  block/export: vhost-user block device backend server
-  block/io: bdrv_aligned_preadv: use and support qiov_offset
+  MAINTAINERS: Add vhost-user block device backend server maintainer
   block/io: bdrv_aligned_pwritev: use and support qiov_offset
   block/io: introduce bdrv_co_p{read, write}v_part
   block/qcow2: refactor qcow2_co_preadv to use buffer-based io
   block/qcow2: implement .bdrv_co_preadv_part
   block/qcow2: implement .bdrv_co_pwritev(_compressed)_part
- block/qcow2.h             |   1 +
+Philippe Mathieu-Daudé (1):
- include/block/block_int.h |  21 ++
+  block/nvme: Add driver statistics for access alignment and hw errors
- include/qemu/iov.h        |  10 +-
- block/backup.c            |   2 +-
+Stefan Hajnoczi (16):
- block/io.c                | 541 +++++++++++++++++++++++---------------
+  util/vhost-user-server: s/fileds/fields/ typo fix
- block/qcow2-cluster.c     |  14 +-
+  util/vhost-user-server: drop unnecessary QOM cast
- block/qcow2.c             | 131 +++++----
+  util/vhost-user-server: drop unnecessary watch deletion
- qemu-img.c                |   4 +-
+  block/export: consolidate request structs into VuBlockReq
- util/iov.c                | 153 +++++++++--
+  util/vhost-user-server: drop unused DevicePanicNotifier
-files changed, 568 insertions(+), 309 deletions(-)
+  util/vhost-user-server: fix memory leak in vu_message_read()
   util/vhost-user-server: check EOF when reading payload
   util/vhost-user-server: rework vu_client_trip() coroutine lifecycle
   block/export: report flush errors
   block/export: convert vhost-user-blk server to block export API
   util/vhost-user-server: move header to include/
   util/vhost-user-server: use static library in meson.build
   qemu-storage-daemon: avoid compiling blockdev_ss twice
   block: move block exports to libblockdev
   block/export: add iothread and fixed-iothread options
   block/export: add vhost-user-blk multi-queue support
 Vladimir Sementsov-Ogievskiy (5):
   block/io: fix bdrv_co_block_status_above
   block/io: bdrv_common_block_status_above: support include_base
   block/io: bdrv_common_block_status_above: support bs == base
   block/io: fix bdrv_is_allocated_above
   iotests: add commit top->base cases to 274
  MAINTAINERS                                |   9 +
  qapi/block-core.json                       |  24 +-
  qapi/block-export.json                     |  36 +-
  block/coroutines.h                         |   2 +
  block/export/vhost-user-blk-server.h       |  19 +
  contrib/libvhost-user/libvhost-user.h      |  21 +
  include/qemu/vhost-user-server.h           |  65 +++
  util/block-helpers.h                       |  19 +
  block/export/export.c                      |  37 +-
  block/export/vhost-user-blk-server.c       | 431 ++++++++++++++++++++
  block/io.c                                 | 132 +++---
  block/nvme.c                               |  27 ++
  block/qcow2.c                              |  16 +-
  contrib/libvhost-user/libvhost-user-glib.c |   2 +-
  contrib/libvhost-user/libvhost-user.c      |  15 +-
  hw/core/qdev-properties-system.c           |  31 +-
  nbd/server.c                               |   2 -
  qemu-nbd.c                                 |  21 +-
  softmmu/vl.c                               |   4 +
  stubs/blk-exp-close-all.c                  |   7 +
  tests/vhost-user-bridge.c                  |   2 +
  tools/virtiofsd/fuse_virtio.c              |   4 +-
  util/block-helpers.c                       |  46 +++
  util/vhost-user-server.c                   | 446 +++++++++++++++++++++
  block/export/meson.build                   |   3 +-
  contrib/libvhost-user/meson.build          |   1 +
  meson.build                                |  22 +-
  nbd/meson.build                            |   2 +
  storage-daemon/meson.build                 |   3 +-
  stubs/meson.build                          |   1 +
  tests/qemu-iotests/274                     |  20 +
  tests/qemu-iotests/274.out                 |  68 ++++
  util/meson.build                           |   4 +
 files changed, 1420 insertions(+), 122 deletions(-)
  create mode 100644 block/export/vhost-user-blk-server.h
  create mode 100644 include/qemu/vhost-user-server.h
  create mode 100644 util/block-helpers.h
  create mode 100644 block/export/vhost-user-blk-server.c
  create mode 100644 stubs/blk-exp-close-all.c
  create mode 100644 util/block-helpers.c
  create mode 100644 util/vhost-user-server.c
 --
-.21.0
+.26.2

-[Qemu-devel] [PULL 12/12] block/qcow2: implement .bdrv_co_pwritev(_compressed)_part
+[PULL v2 01/28] block/nvme: Add driver statistics for access alignment and hw errors
-From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+From: Philippe Mathieu-Daudé <philmd@redhat.com>
-Implement and use new interface to get rid of hd_qiov.
+Keep statistics of some hardware errors, and number of
 aligned/unaligned I/O accesses.
-Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+QMP example booting a full RHEL 8.3 aarch64 guest:
-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
-Message-id: 20190604161514.262241-13-vsementsov@virtuozzo.com
+{ "execute": "query-blockstats" }
-Message-Id: <20190604161514.262241-13-vsementsov@virtuozzo.com>
+{
     "return": [
         {
             "device": "",
             "node-name": "drive0",
             "stats": {
                 "flush_total_time_ns": 6026948,
                 "wr_highest_offset": 3383991230464,
                 "wr_total_time_ns": 807450995,
                 "failed_wr_operations": 0,
                 "failed_rd_operations": 0,
                 "wr_merged": 3,
                 "wr_bytes": 50133504,
                 "failed_unmap_operations": 0,
                 "failed_flush_operations": 0,
                 "account_invalid": false,
                 "rd_total_time_ns": 1846979900,
                 "flush_operations": 130,
                 "wr_operations": 659,
                 "rd_merged": 1192,
                 "rd_bytes": 218244096,
                 "account_failed": false,
                 "idle_time_ns": 2678641497,
                 "rd_operations": 7406,
             },
             "driver-specific": {
                 "driver": "nvme",
                 "completion-errors": 0,
                 "unaligned-accesses": 2959,
                 "aligned-accesses": 4477
             },
             "qdev": "/machine/peripheral-anon/device[0]/virtio-backend"
         }
     ]
 }
 Suggested-by: Stefan Hajnoczi <stefanha@gmail.com>
 Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
 Acked-by: Markus Armbruster <armbru@redhat.com>
 Message-id: 20201001162939.1567915-1-philmd@redhat.com
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- block/qcow2.h         |  1 +
+ qapi/block-core.json | 24 +++++++++++++++++++++++-
- include/qemu/iov.h    |  1 +
+ block/nvme.c         | 27 +++++++++++++++++++++++++++
- block/qcow2-cluster.c |  9 ++++---
+files changed, 50 insertions(+), 1 deletion(-)
  block/qcow2.c         | 60 +++++++++++++++++++++----------------------
  util/iov.c            | 10 ++++++++
 files changed, 48 insertions(+), 33 deletions(-)
-diff --git a/block/qcow2.h b/block/qcow2.h
+diff --git a/qapi/block-core.json b/qapi/block-core.json
 index XXXXXXX..XXXXXXX 100644
---- a/block/qcow2.h
+--- a/qapi/block-core.json
-+++ b/block/qcow2.h
++++ b/qapi/block-core.json
-@@ -XXX,XX +XXX,XX @@ typedef struct QCowL2Meta
+@@ -XXX,XX +XXX,XX @@
-      * from @cow_start and @cow_end into one single write operation.
+       'discard-nb-failed': 'uint64',
-      */
+       'discard-bytes-ok': 'uint64' } }
-     QEMUIOVector *data_qiov;
-+    size_t data_qiov_offset;
++##
++# @BlockStatsSpecificNvme:
-     /** Pointer to next L2Meta of the same write request */
++#
-     struct QCowL2Meta *next;
++# NVMe driver statistics
-diff --git a/include/qemu/iov.h b/include/qemu/iov.h
++#
 +# @completion-errors: The number of completion errors.
 +#
 +# @aligned-accesses: The number of aligned accesses performed by
 +#                    the driver.
 +#
 +# @unaligned-accesses: The number of unaligned accesses performed by
 +#                      the driver.
 +#
 +# Since: 5.2
 +##
 +{ 'struct': 'BlockStatsSpecificNvme',
 +  'data': {
 +      'completion-errors': 'uint64',
 +      'aligned-accesses': 'uint64',
 +      'unaligned-accesses': 'uint64' } }
 +
  ##
  # @BlockStatsSpecific:
  #
@@ -XXX,XX +XXX,XX @@
    'discriminator': 'driver',
    'data': {
        'file': 'BlockStatsSpecificFile',
 -      'host_device': 'BlockStatsSpecificFile' } }
 +      'host_device': 'BlockStatsSpecificFile',
 +      'nvme': 'BlockStatsSpecificNvme' } }
  ##
  # @BlockStats:
 diff --git a/block/nvme.c b/block/nvme.c
 index XXXXXXX..XXXXXXX 100644
---- a/include/qemu/iov.h
+--- a/block/nvme.c
-+++ b/include/qemu/iov.h
++++ b/block/nvme.c
-@@ -XXX,XX +XXX,XX @@ void qemu_iovec_init_extended(
+@@ -XXX,XX +XXX,XX @@ struct BDRVNVMeState {
-         void *tail_buf, size_t tail_len);
- void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source,
+     /* PCI address (required for nvme_refresh_filename()) */
-                            size_t offset, size_t len);
+     char *device;
-+int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len);
++
- void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len);
++    struct {
- void qemu_iovec_concat(QEMUIOVector *dst,
++        uint64_t completion_errors;
-                        QEMUIOVector *src, size_t soffset, size_t sbytes);
++        uint64_t aligned_accesses;
-diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
++        uint64_t unaligned_accesses;
-index XXXXXXX..XXXXXXX 100644
++    } stats;
---- a/block/qcow2-cluster.c
+ };
-+++ b/block/qcow2-cluster.c
-@@ -XXX,XX +XXX,XX @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m)
+ #define NVME_BLOCK_OPT_DEVICE "device"
-     assert(start->nb_bytes <= UINT_MAX - end->nb_bytes);
+@@ -XXX,XX +XXX,XX @@ static bool nvme_process_completion(NVMeQueuePair *q)
-     assert(start->nb_bytes + end->nb_bytes <= UINT_MAX - data_bytes);
+             break;
      assert(start->offset + start->nb_bytes <= end->offset);
 -    assert(!m->data_qiov || m->data_qiov->size == data_bytes);
      if ((start->nb_bytes == 0 && end->nb_bytes == 0) || m->skip_cow) {
          return 0;
@@ -XXX,XX +XXX,XX @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m)
      /* The part of the buffer where the end region is located */
      end_buffer = start_buffer + buffer_size - end->nb_bytes;
 -    qemu_iovec_init(&qiov, 2 + (m->data_qiov ? m->data_qiov->niov : 0));
 +    qemu_iovec_init(&qiov, 2 + (m->data_qiov ?
 +                                qemu_iovec_subvec_niov(m->data_qiov,
 +                                                       m->data_qiov_offset,
 +                                                       data_bytes)
 +                                : 0));
      qemu_co_mutex_unlock(&s->lock);
      /* First we read the existing data from both COW regions. We
@@ -XXX,XX +XXX,XX @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m)
          if (start->nb_bytes) {
              qemu_iovec_add(&qiov, start_buffer, start->nb_bytes);
          }
--        qemu_iovec_concat(&qiov, m->data_qiov, 0, data_bytes);
+         ret = nvme_translate_error(c);
-+        qemu_iovec_concat(&qiov, m->data_qiov, m->data_qiov_offset, data_bytes);
++        if (ret) {
-         if (end->nb_bytes) {
++            s->stats.completion_errors++;
-             qemu_iovec_add(&qiov, end_buffer, end->nb_bytes);
++        }
-         }
+         q->cq.head = (q->cq.head + 1) % NVME_QUEUE_SIZE;
-diff --git a/block/qcow2.c b/block/qcow2.c
+         if (!q->cq.head) {
-index XXXXXXX..XXXXXXX 100644
+             q->cq_phase = !q->cq_phase;
---- a/block/qcow2.c
+@@ -XXX,XX +XXX,XX @@ static int nvme_co_prw(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
-+++ b/block/qcow2.c
+     assert(QEMU_IS_ALIGNED(bytes, s->page_size));
-@@ -XXX,XX +XXX,XX @@ fail:
+     assert(bytes <= s->max_transfer);
- /* Check if it's possible to merge a write request with the writing of
+     if (nvme_qiov_aligned(bs, qiov)) {
-  * the data from the COW regions */
++        s->stats.aligned_accesses++;
- static bool merge_cow(uint64_t offset, unsigned bytes,
+         return nvme_co_prw_aligned(bs, offset, bytes, qiov, is_write, flags);
 -                      QEMUIOVector *hd_qiov, QCowL2Meta *l2meta)
 +                      QEMUIOVector *qiov, size_t qiov_offset,
 +                      QCowL2Meta *l2meta)
  {
      QCowL2Meta *m;
@@ -XXX,XX +XXX,XX @@ static bool merge_cow(uint64_t offset, unsigned bytes,
          /* Make sure that adding both COW regions to the QEMUIOVector
           * does not exceed IOV_MAX */
 -        if (hd_qiov->niov > IOV_MAX - 2) {
 +        if (qemu_iovec_subvec_niov(qiov, qiov_offset, bytes) > IOV_MAX - 2) {
              continue;
          }
 -        m->data_qiov = hd_qiov;
 +        m->data_qiov = qiov;
 +        m->data_qiov_offset = qiov_offset;
          return true;
      }
++    s->stats.unaligned_accesses++;
-@@ -XXX,XX +XXX,XX @@ static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta)
+     trace_nvme_prw_buffered(s, offset, bytes, qiov->niov, is_write);
-     return 0;
+     buf = qemu_try_memalign(s->page_size, bytes);
@@ -XXX,XX +XXX,XX @@ static void nvme_unregister_buf(BlockDriverState *bs, void *host)
      qemu_vfio_dma_unmap(s->vfio, host);
  }
--static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
++static BlockStatsSpecific *nvme_get_specific_stats(BlockDriverState *bs)
 -                                         uint64_t bytes, QEMUIOVector *qiov,
 -                                         int flags)
 +static coroutine_fn int qcow2_co_pwritev_part(
 +        BlockDriverState *bs, uint64_t offset, uint64_t bytes,
 +        QEMUIOVector *qiov, size_t qiov_offset, int flags)
  {
      BDRVQcow2State *s = bs->opaque;
      int offset_in_cluster;
      int ret;
      unsigned int cur_bytes; /* number of sectors in current iteration */
      uint64_t cluster_offset;
 -    QEMUIOVector hd_qiov;
 +    QEMUIOVector encrypted_qiov;
      uint64_t bytes_done = 0;
      uint8_t *cluster_data = NULL;
      QCowL2Meta *l2meta = NULL;
      trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes);
 -    qemu_iovec_init(&hd_qiov, qiov->niov);
 -
      qemu_co_mutex_lock(&s->lock);
      while (bytes != 0) {
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
          qemu_co_mutex_unlock(&s->lock);
 -        qemu_iovec_reset(&hd_qiov);
 -        qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
 -
          if (bs->encrypted) {
              assert(s->crypto);
              if (!cluster_data) {
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
                  }
              }
 -            assert(hd_qiov.size <=
 -                   QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
 -            qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);
 +            assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
 +            qemu_iovec_to_buf(qiov, qiov_offset + bytes_done,
 +                              cluster_data, cur_bytes);
              if (qcow2_co_encrypt(bs, cluster_offset, offset,
                                   cluster_data, cur_bytes) < 0) {
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
                  goto out_unlocked;
              }
 -            qemu_iovec_reset(&hd_qiov);
 -            qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
 +            qemu_iovec_init_buf(&encrypted_qiov, cluster_data, cur_bytes);
          }
          /* Try to efficiently initialize the physical space with zeroes */
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
           * writing of the guest data together with that of the COW regions.
           * If it's not possible (or not necessary) then write the
           * guest data now. */
 -        if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) {
 +        if (!merge_cow(offset, cur_bytes,
 +                       bs->encrypted ? &encrypted_qiov : qiov,
 +                       bs->encrypted ? 0 : qiov_offset + bytes_done, l2meta))
 +        {
              BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
              trace_qcow2_writev_data(qemu_coroutine_self(),
                                      cluster_offset + offset_in_cluster);
 -            ret = bdrv_co_pwritev(s->data_file,
 -                                  cluster_offset + offset_in_cluster,
 -                                  cur_bytes, &hd_qiov, 0);
 +            ret = bdrv_co_pwritev_part(
 +                    s->data_file, cluster_offset + offset_in_cluster, cur_bytes,
 +                    bs->encrypted ? &encrypted_qiov : qiov,
 +                    bs->encrypted ? 0 : qiov_offset + bytes_done, 0);
              if (ret < 0) {
                  goto out_unlocked;
              }
@@ -XXX,XX +XXX,XX @@ out_locked:
      qemu_co_mutex_unlock(&s->lock);
 -    qemu_iovec_destroy(&hd_qiov);
      qemu_vfree(cluster_data);
      trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
@@ -XXX,XX +XXX,XX @@ fail:
  /* XXX: put compressed sectors first, then all the cluster aligned
     tables to avoid losing bytes in alignment */
  static coroutine_fn int
 -qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
 -                            uint64_t bytes, QEMUIOVector *qiov)
 +qcow2_co_pwritev_compressed_part(BlockDriverState *bs,
 +                                 uint64_t offset, uint64_t bytes,
 +                                 QEMUIOVector *qiov, size_t qiov_offset)
  {
      BDRVQcow2State *s = bs->opaque;
      int ret;
@@ -XXX,XX +XXX,XX @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
          /* Zero-pad last write if image size is not cluster aligned */
          memset(buf + bytes, 0, s->cluster_size - bytes);
      }
 -    qemu_iovec_to_buf(qiov, 0, buf, bytes);
 +    qemu_iovec_to_buf(qiov, qiov_offset, buf, bytes);
      out_buf = g_malloc(s->cluster_size);
@@ -XXX,XX +XXX,XX @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
                                  buf, s->cluster_size);
      if (out_len == -ENOMEM) {
          /* could not compress: write normal cluster */
 -        ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0);
 +        ret = qcow2_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset, 0);
          if (ret < 0) {
              goto fail;
          }
@@ -XXX,XX +XXX,XX @@ static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
      BDRVQcow2State *s = bs->opaque;
      BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
 -    return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos,
 -                                    qiov->size, qiov, 0);
 +    return bs->drv->bdrv_co_pwritev_part(bs, qcow2_vm_state_offset(s) + pos,
 +                                         qiov->size, qiov, 0, 0);
  }
  static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
@@ -XXX,XX +XXX,XX @@ BlockDriver bdrv_qcow2 = {
      .bdrv_co_block_status = qcow2_co_block_status,
      .bdrv_co_preadv_part    = qcow2_co_preadv_part,
 -    .bdrv_co_pwritev        = qcow2_co_pwritev,
 +    .bdrv_co_pwritev_part   = qcow2_co_pwritev_part,
      .bdrv_co_flush_to_os    = qcow2_co_flush_to_os,
      .bdrv_co_pwrite_zeroes  = qcow2_co_pwrite_zeroes,
@@ -XXX,XX +XXX,XX @@ BlockDriver bdrv_qcow2 = {
      .bdrv_co_copy_range_from = qcow2_co_copy_range_from,
      .bdrv_co_copy_range_to  = qcow2_co_copy_range_to,
      .bdrv_co_truncate       = qcow2_co_truncate,
 -    .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed,
 +    .bdrv_co_pwritev_compressed_part = qcow2_co_pwritev_compressed_part,
      .bdrv_make_empty        = qcow2_make_empty,
      .bdrv_snapshot_create   = qcow2_snapshot_create,
 diff --git a/util/iov.c b/util/iov.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/iov.c
 +++ b/util/iov.c
@@ -XXX,XX +XXX,XX @@ static struct iovec *qiov_slice(QEMUIOVector *qiov,
      return iov;
  }
 +int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len)
 +{
-+    size_t head, tail;
++    BlockStatsSpecific *stats = g_new(BlockStatsSpecific, 1);
-+    int niov;
++    BDRVNVMeState *s = bs->opaque;
 +
-+    qiov_slice(qiov, offset, len, &head, &tail, &niov);
++    stats->driver = BLOCKDEV_DRIVER_NVME;
 +    stats->u.nvme = (BlockStatsSpecificNvme) {
 +        .completion_errors = s->stats.completion_errors,
 +        .aligned_accesses = s->stats.aligned_accesses,
 +        .unaligned_accesses = s->stats.unaligned_accesses,
 +    };
 +
-+    return niov;
++    return stats;
 +}
 +
- /*
+ static const char *const nvme_strong_runtime_opts[] = {
-  * Compile new iovec, combining @head_buf buffer, sub-qiov of @mid_qiov,
+     NVME_BLOCK_OPT_DEVICE,
-  * and @tail_buf buffer into new qiov.
+     NVME_BLOCK_OPT_NAMESPACE,
@@ -XXX,XX +XXX,XX @@ static BlockDriver bdrv_nvme = {
      .bdrv_refresh_filename    = nvme_refresh_filename,
      .bdrv_refresh_limits      = nvme_refresh_limits,
      .strong_runtime_opts      = nvme_strong_runtime_opts,
 +    .bdrv_get_specific_stats  = nvme_get_specific_stats,
      .bdrv_detach_aio_context  = nvme_detach_aio_context,
      .bdrv_attach_aio_context  = nvme_attach_aio_context,
 --
-.21.0
+.26.2

-[Qemu-devel] [PULL 09/12] block/io: introduce bdrv_co_p{read, write}v_part
+[PULL v2 02/28] libvhost-user: Allow vu_message_read to be replaced
-From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+From: Coiby Xu <coiby.xu@gmail.com>
-Introduce extended variants of bdrv_co_preadv and bdrv_co_pwritev
+Allow vu_message_read to be replaced by one which will make use of the
-with qiov_offset parameter.
+QIOChannel functions. Thus reading vhost-user message won't stall the
 guest. For slave channel, we still use the default vu_message_read.
-Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
+Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
-Message-id: 20190604161514.262241-10-vsementsov@virtuozzo.com
+Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Message-Id: <20190604161514.262241-10-vsementsov@virtuozzo.com>
+Message-id: 20200918080912.321299-2-coiby.xu@gmail.com
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- include/block/block_int.h |  6 ++++++
+ contrib/libvhost-user/libvhost-user.h      | 21 +++++++++++++++++++++
- block/io.c                | 29 +++++++++++++++++++++++------
+ contrib/libvhost-user/libvhost-user-glib.c |  2 +-
-files changed, 29 insertions(+), 6 deletions(-)
+ contrib/libvhost-user/libvhost-user.c      | 14 +++++++-------
  tests/vhost-user-bridge.c                  |  2 ++
  tools/virtiofsd/fuse_virtio.c              |  4 ++--
 files changed, 33 insertions(+), 10 deletions(-)
-diff --git a/include/block/block_int.h b/include/block/block_int.h
+diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h
 index XXXXXXX..XXXXXXX 100644
---- a/include/block/block_int.h
+--- a/contrib/libvhost-user/libvhost-user.h
-+++ b/include/block/block_int.h
++++ b/contrib/libvhost-user/libvhost-user.h
-@@ -XXX,XX +XXX,XX @@ extern BlockDriver bdrv_qcow2;
+@@ -XXX,XX +XXX,XX @@
- int coroutine_fn bdrv_co_preadv(BdrvChild *child,
+  */
-     int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+ #define VHOST_USER_MAX_RAM_SLOTS 32
-     BdrvRequestFlags flags);
-+int coroutine_fn bdrv_co_preadv_part(BdrvChild *child,
++#define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
-+    int64_t offset, unsigned int bytes,
++
-+    QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags);
+ typedef enum VhostSetConfigType {
- int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
+     VHOST_SET_CONFIG_TYPE_MASTER = 0,
-     int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+     VHOST_SET_CONFIG_TYPE_MIGRATION = 1,
-     BdrvRequestFlags flags);
+@@ -XXX,XX +XXX,XX @@ typedef uint64_t (*vu_get_features_cb) (VuDev *dev);
-+int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child,
+ typedef void (*vu_set_features_cb) (VuDev *dev, uint64_t features);
-+    int64_t offset, unsigned int bytes,
+ typedef int (*vu_process_msg_cb) (VuDev *dev, VhostUserMsg *vmsg,
-+    QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags);
+                                   int *do_reply);
++typedef bool (*vu_read_msg_cb) (VuDev *dev, int sock, VhostUserMsg *vmsg);
- static inline int coroutine_fn bdrv_co_pread(BdrvChild *child,
+ typedef void (*vu_queue_set_started_cb) (VuDev *dev, int qidx, bool started);
-     int64_t offset, unsigned int bytes, void *buf, BdrvRequestFlags flags)
+ typedef bool (*vu_queue_is_processed_in_order_cb) (VuDev *dev, int qidx);
-diff --git a/block/io.c b/block/io.c
+ typedef int (*vu_get_config_cb) (VuDev *dev, uint8_t *config, uint32_t len);
@@ -XXX,XX +XXX,XX @@ struct VuDev {
      bool broken;
      uint16_t max_queues;
 +    /* @read_msg: custom method to read vhost-user message
 +     *
 +     * Read data from vhost_user socket fd and fill up
 +     * the passed VhostUserMsg *vmsg struct.
 +     *
 +     * If reading fails, it should close the received set of file
 +     * descriptors as socket message's auxiliary data.
 +     *
 +     * For the details, please refer to vu_message_read in libvhost-user.c
 +     * which will be used by default if not custom method is provided when
 +     * calling vu_init
 +     *
 +     * Returns: true if vhost-user message successfully received,
 +     *          otherwise return false.
 +     *
 +     */
 +    vu_read_msg_cb read_msg;
      /* @set_watch: add or update the given fd to the watch set,
       * call cb when condition is met */
      vu_set_watch_cb set_watch;
@@ -XXX,XX +XXX,XX @@ bool vu_init(VuDev *dev,
               uint16_t max_queues,
               int socket,
               vu_panic_cb panic,
 +             vu_read_msg_cb read_msg,
               vu_set_watch_cb set_watch,
               vu_remove_watch_cb remove_watch,
               const VuDevIface *iface);
 diff --git a/contrib/libvhost-user/libvhost-user-glib.c b/contrib/libvhost-user/libvhost-user-glib.c
 index XXXXXXX..XXXXXXX 100644
---- a/block/io.c
+--- a/contrib/libvhost-user/libvhost-user-glib.c
-+++ b/block/io.c
++++ b/contrib/libvhost-user/libvhost-user-glib.c
-@@ -XXX,XX +XXX,XX @@ static void bdrv_padding_destroy(BdrvRequestPadding *pad)
+@@ -XXX,XX +XXX,XX @@ vug_init(VugDev *dev, uint16_t max_queues, int socket,
-  *
+     g_assert(dev);
-  * Function always succeeds.
+     g_assert(iface);
-  */
--static bool bdrv_pad_request(BlockDriverState *bs, QEMUIOVector **qiov,
+-    if (!vu_init(&dev->parent, max_queues, socket, panic, set_watch,
-+static bool bdrv_pad_request(BlockDriverState *bs,
++    if (!vu_init(&dev->parent, max_queues, socket, panic, NULL, set_watch,
-+                             QEMUIOVector **qiov, size_t *qiov_offset,
+                  remove_watch, iface)) {
-                              int64_t *offset, unsigned int *bytes,
+         return false;
-                              BdrvRequestPadding *pad)
+     }
 diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
 index XXXXXXX..XXXXXXX 100644
 --- a/contrib/libvhost-user/libvhost-user.c
 +++ b/contrib/libvhost-user/libvhost-user.c
@@ -XXX,XX +XXX,XX @@
  /* The version of inflight buffer */
  #define INFLIGHT_VERSION 1
 -#define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
 -
  /* The version of the protocol we support */
  #define VHOST_USER_VERSION 1
  #define LIBVHOST_USER_DEBUG 0
@@ -XXX,XX +XXX,XX @@ have_userfault(void)
  }
  static bool
 -vu_message_read(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
 +vu_message_read_default(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
  {
-@@ -XXX,XX +XXX,XX @@ static bool bdrv_pad_request(BlockDriverState *bs, QEMUIOVector **qiov,
+     char control[CMSG_SPACE(VHOST_MEMORY_BASELINE_NREGIONS * sizeof(int))] = {};
-     }
+     struct iovec iov = {
+@@ -XXX,XX +XXX,XX @@ vu_process_message_reply(VuDev *dev, const VhostUserMsg *vmsg)
      qemu_iovec_init_extended(&pad->local_qiov, pad->buf, pad->head,
 -                             *qiov, 0, *bytes,
 +                             *qiov, *qiov_offset, *bytes,
                               pad->buf + pad->buf_len - pad->tail, pad->tail);
      *bytes += pad->head + pad->tail;
      *offset -= pad->head;
      *qiov = &pad->local_qiov;
 +    *qiov_offset = 0;
      return true;
  }
@@ -XXX,XX +XXX,XX @@ static bool bdrv_pad_request(BlockDriverState *bs, QEMUIOVector **qiov,
  int coroutine_fn bdrv_co_preadv(BdrvChild *child,
      int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
      BdrvRequestFlags flags)
 +{
 +    return bdrv_co_preadv_part(child, offset, bytes, qiov, 0, flags);
 +}
 +
 +int coroutine_fn bdrv_co_preadv_part(BdrvChild *child,
 +    int64_t offset, unsigned int bytes,
 +    QEMUIOVector *qiov, size_t qiov_offset,
 +    BdrvRequestFlags flags)
  {
      BlockDriverState *bs = child->bs;
      BdrvTrackedRequest req;
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child,
          flags |= BDRV_REQ_COPY_ON_READ;
      }
 -    bdrv_pad_request(bs, &qiov, &offset, &bytes, &pad);
 +    bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, &pad);
      tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_READ);
      ret = bdrv_aligned_preadv(child, &req, offset, bytes,
                                bs->bl.request_alignment,
 -                              qiov, 0, flags);
 +                              qiov, qiov_offset, flags);
      tracked_request_end(&req);
      bdrv_dec_in_flight(bs);
@@ -XXX,XX +XXX,XX @@ out:
  int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
      int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
      BdrvRequestFlags flags)
 +{
 +    return bdrv_co_pwritev_part(child, offset, bytes, qiov, 0, flags);
 +}
 +
 +int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child,
 +    int64_t offset, unsigned int bytes, QEMUIOVector *qiov, size_t qiov_offset,
 +    BdrvRequestFlags flags)
  {
      BlockDriverState *bs = child->bs;
      BdrvTrackedRequest req;
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
          goto out;
      }
--    if (bdrv_pad_request(bs, &qiov, &offset, &bytes, &pad)) {
+-    if (!vu_message_read(dev, dev->slave_fd, &msg_reply)) {
-+    if (bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, &pad)) {
++    if (!vu_message_read_default(dev, dev->slave_fd, &msg_reply)) {
-         mark_request_serialising(&req, align);
+         goto out;
          wait_serialising_requests(&req);
          bdrv_padding_rmw_read(child, &req, &pad, false);
      }
-     ret = bdrv_aligned_pwritev(child, &req, offset, bytes, align,
+@@ -XXX,XX +XXX,XX @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
--                               qiov, 0, flags);
+     /* Wait for QEMU to confirm that it's registered the handler for the
-+                               qiov, qiov_offset, flags);
+      * faults.
+      */
-     bdrv_padding_destroy(&pad);
+-    if (!vu_message_read(dev, dev->sock, vmsg) ||
++    if (!dev->read_msg(dev, dev->sock, vmsg) ||
          vmsg->size != sizeof(vmsg->payload.u64) ||
          vmsg->payload.u64 != 0) {
          vu_panic(dev, "failed to receive valid ack for postcopy set-mem-table");
@@ -XXX,XX +XXX,XX @@ vu_dispatch(VuDev *dev)
      int reply_requested;
      bool need_reply, success = false;
 -    if (!vu_message_read(dev, dev->sock, &vmsg)) {
 +    if (!dev->read_msg(dev, dev->sock, &vmsg)) {
          goto end;
      }
@@ -XXX,XX +XXX,XX @@ vu_init(VuDev *dev,
          uint16_t max_queues,
          int socket,
          vu_panic_cb panic,
 +        vu_read_msg_cb read_msg,
          vu_set_watch_cb set_watch,
          vu_remove_watch_cb remove_watch,
          const VuDevIface *iface)
@@ -XXX,XX +XXX,XX @@ vu_init(VuDev *dev,
      dev->sock = socket;
      dev->panic = panic;
 +    dev->read_msg = read_msg ? read_msg : vu_message_read_default;
      dev->set_watch = set_watch;
      dev->remove_watch = remove_watch;
      dev->iface = iface;
@@ -XXX,XX +XXX,XX @@ static void _vu_queue_notify(VuDev *dev, VuVirtq *vq, bool sync)
          vu_message_write(dev, dev->slave_fd, &vmsg);
          if (ack) {
 -            vu_message_read(dev, dev->slave_fd, &vmsg);
 +            vu_message_read_default(dev, dev->slave_fd, &vmsg);
          }
          return;
      }
 diff --git a/tests/vhost-user-bridge.c b/tests/vhost-user-bridge.c
 index XXXXXXX..XXXXXXX 100644
 --- a/tests/vhost-user-bridge.c
 +++ b/tests/vhost-user-bridge.c
@@ -XXX,XX +XXX,XX @@ vubr_accept_cb(int sock, void *ctx)
                   VHOST_USER_BRIDGE_MAX_QUEUES,
                   conn_fd,
                   vubr_panic,
 +                 NULL,
                   vubr_set_watch,
                   vubr_remove_watch,
                   &vuiface)) {
@@ -XXX,XX +XXX,XX @@ vubr_new(const char *path, bool client)
                       VHOST_USER_BRIDGE_MAX_QUEUES,
                       dev->sock,
                       vubr_panic,
 +                     NULL,
                       vubr_set_watch,
                       vubr_remove_watch,
                       &vuiface)) {
 diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
 index XXXXXXX..XXXXXXX 100644
 --- a/tools/virtiofsd/fuse_virtio.c
 +++ b/tools/virtiofsd/fuse_virtio.c
@@ -XXX,XX +XXX,XX @@ int virtio_session_mount(struct fuse_session *se)
      se->vu_socketfd = data_sock;
      se->virtio_dev->se = se;
      pthread_rwlock_init(&se->virtio_dev->vu_dispatch_rwlock, NULL);
 -    vu_init(&se->virtio_dev->dev, 2, se->vu_socketfd, fv_panic, fv_set_watch,
 -            fv_remove_watch, &fv_iface);
 +    vu_init(&se->virtio_dev->dev, 2, se->vu_socketfd, fv_panic, NULL,
 +            fv_set_watch, fv_remove_watch, &fv_iface);
      return 0;
  }
 --
-.21.0
+.26.2

-New patch
+[PULL v2 03/28] libvhost-user: remove watch for kick_fd when de-initialize vu-dev
+From: Coiby Xu <coiby.xu@gmail.com>
+When the client is running in gdb and quit command is run in gdb,
+QEMU will still dispatch the event which will cause segment fault in
+the callback function.
+Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
+Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
+Message-id: 20200918080912.321299-3-coiby.xu@gmail.com
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ contrib/libvhost-user/libvhost-user.c | 1 +
+file changed, 1 insertion(+)
+diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
+index XXXXXXX..XXXXXXX 100644
+--- a/contrib/libvhost-user/libvhost-user.c
++++ b/contrib/libvhost-user/libvhost-user.c
+@@ -XXX,XX +XXX,XX @@ vu_deinit(VuDev *dev)
+         }
+         if (vq->kick_fd != -1) {
++            dev->remove_watch(dev, vq->kick_fd);
+             close(vq->kick_fd);
+             vq->kick_fd = -1;
+         }
+--
+.26.2

-New patch
+[PULL v2 04/28] util/vhost-user-server: generic vhost user server
+From: Coiby Xu <coiby.xu@gmail.com>
+Sharing QEMU devices via vhost-user protocol.
+Only one vhost-user client can connect to the server one time.
+Suggested-by: Kevin Wolf <kwolf@redhat.com>
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
+Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
+Message-id: 20200918080912.321299-4-coiby.xu@gmail.com
+[Fixed size_t %lu -> %zu format string compiler error.
+--Stefan]
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ util/vhost-user-server.h |  65 ++++++
+ util/vhost-user-server.c | 428 +++++++++++++++++++++++++++++++++++++++
+ util/meson.build         |   1 +
+files changed, 494 insertions(+)
+ create mode 100644 util/vhost-user-server.h
+ create mode 100644 util/vhost-user-server.c
+diff --git a/util/vhost-user-server.h b/util/vhost-user-server.h
+new file mode 100644
+index XXXXXXX..XXXXXXX
+--- /dev/null
++++ b/util/vhost-user-server.h
+@@ -XXX,XX +XXX,XX @@
++/*
++ * Sharing QEMU devices via vhost-user protocol
++ *
++ * Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
++ * Copyright (c) 2020 Red Hat, Inc.
++ *
++ * This work is licensed under the terms of the GNU GPL, version 2 or
++ * later.  See the COPYING file in the top-level directory.
++ */
++
++#ifndef VHOST_USER_SERVER_H
++#define VHOST_USER_SERVER_H
++
++#include "contrib/libvhost-user/libvhost-user.h"
++#include "io/channel-socket.h"
++#include "io/channel-file.h"
++#include "io/net-listener.h"
++#include "qemu/error-report.h"
++#include "qapi/error.h"
++#include "standard-headers/linux/virtio_blk.h"
++
++typedef struct VuFdWatch {
++    VuDev *vu_dev;
++    int fd; /*kick fd*/
++    void *pvt;
++    vu_watch_cb cb;
++    bool processing;
++    QTAILQ_ENTRY(VuFdWatch) next;
++} VuFdWatch;
++
++typedef struct VuServer VuServer;
++typedef void DevicePanicNotifierFn(VuServer *server);
++
++struct VuServer {
++    QIONetListener *listener;
++    AioContext *ctx;
++    DevicePanicNotifierFn *device_panic_notifier;
++    int max_queues;
++    const VuDevIface *vu_iface;
++    VuDev vu_dev;
++    QIOChannel *ioc; /* The I/O channel with the client */
++    QIOChannelSocket *sioc; /* The underlying data channel with the client */
++    /* IOChannel for fd provided via VHOST_USER_SET_SLAVE_REQ_FD */
++    QIOChannel *ioc_slave;
++    QIOChannelSocket *sioc_slave;
++    Coroutine *co_trip; /* coroutine for processing VhostUserMsg */
++    QTAILQ_HEAD(, VuFdWatch) vu_fd_watches;
++    /* restart coroutine co_trip if AIOContext is changed */
++    bool aio_context_changed;
++    bool processing_msg;
++};
++
++bool vhost_user_server_start(VuServer *server,
++                             SocketAddress *unix_socket,
++                             AioContext *ctx,
++                             uint16_t max_queues,
++                             DevicePanicNotifierFn *device_panic_notifier,
++                             const VuDevIface *vu_iface,
++                             Error **errp);
++
++void vhost_user_server_stop(VuServer *server);
++
++void vhost_user_server_set_aio_context(VuServer *server, AioContext *ctx);
++
++#endif /* VHOST_USER_SERVER_H */
+diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
+new file mode 100644
+index XXXXXXX..XXXXXXX
+--- /dev/null
++++ b/util/vhost-user-server.c
+@@ -XXX,XX +XXX,XX @@
++/*
++ * Sharing QEMU devices via vhost-user protocol
++ *
++ * Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
++ * Copyright (c) 2020 Red Hat, Inc.
++ *
++ * This work is licensed under the terms of the GNU GPL, version 2 or
++ * later.  See the COPYING file in the top-level directory.
++ */
++#include "qemu/osdep.h"
++#include "qemu/main-loop.h"
++#include "vhost-user-server.h"
++
++static void vmsg_close_fds(VhostUserMsg *vmsg)
++{
++    int i;
++    for (i = 0; i < vmsg->fd_num; i++) {
++        close(vmsg->fds[i]);
++    }
++}
++
++static void vmsg_unblock_fds(VhostUserMsg *vmsg)
++{
++    int i;
++    for (i = 0; i < vmsg->fd_num; i++) {
++        qemu_set_nonblock(vmsg->fds[i]);
++    }
++}
++
++static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
++                      gpointer opaque);
++
++static void close_client(VuServer *server)
++{
++    /*
++     * Before closing the client
++     *
++     * 1. Let vu_client_trip stop processing new vhost-user msg
++     *
++     * 2. remove kick_handler
++     *
++     * 3. wait for the kick handler to be finished
++     *
++     * 4. wait for the current vhost-user msg to be finished processing
++     */
++
++    QIOChannelSocket *sioc = server->sioc;
++    /* When this is set vu_client_trip will stop new processing vhost-user message */
++    server->sioc = NULL;
++
++    VuFdWatch *vu_fd_watch, *next;
++    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
++        aio_set_fd_handler(server->ioc->ctx, vu_fd_watch->fd, true, NULL,
++                           NULL, NULL, NULL);
++    }
++
++    while (!QTAILQ_EMPTY(&server->vu_fd_watches)) {
++        QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
++            if (!vu_fd_watch->processing) {
++                QTAILQ_REMOVE(&server->vu_fd_watches, vu_fd_watch, next);
++                g_free(vu_fd_watch);
++            }
++        }
++    }
++
++    while (server->processing_msg) {
++        if (server->ioc->read_coroutine) {
++            server->ioc->read_coroutine = NULL;
++            qio_channel_set_aio_fd_handler(server->ioc, server->ioc->ctx, NULL,
++                                           NULL, server->ioc);
++            server->processing_msg = false;
++        }
++    }
++
++    vu_deinit(&server->vu_dev);
++    object_unref(OBJECT(sioc));
++    object_unref(OBJECT(server->ioc));
++}
++
++static void panic_cb(VuDev *vu_dev, const char *buf)
++{
++    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
++
++    /* avoid while loop in close_client */
++    server->processing_msg = false;
++
++    if (buf) {
++        error_report("vu_panic: %s", buf);
++    }
++
++    if (server->sioc) {
++        close_client(server);
++    }
++
++    if (server->device_panic_notifier) {
++        server->device_panic_notifier(server);
++    }
++
++    /*
++     * Set the callback function for network listener so another
++     * vhost-user client can connect to this server
++     */
++    qio_net_listener_set_client_func(server->listener,
++                                     vu_accept,
++                                     server,
++                                     NULL);
++}
++
++static bool coroutine_fn
++vu_message_read(VuDev *vu_dev, int conn_fd, VhostUserMsg *vmsg)
++{
++    struct iovec iov = {
++        .iov_base = (char *)vmsg,
++        .iov_len = VHOST_USER_HDR_SIZE,
++    };
++    int rc, read_bytes = 0;
++    Error *local_err = NULL;
++    /*
++     * Store fds/nfds returned from qio_channel_readv_full into
++     * temporary variables.
++     *
++     * VhostUserMsg is a packed structure, gcc will complain about passing
++     * pointer to a packed structure member if we pass &VhostUserMsg.fd_num
++     * and &VhostUserMsg.fds directly when calling qio_channel_readv_full,
++     * thus two temporary variables nfds and fds are used here.
++     */
++    size_t nfds = 0, nfds_t = 0;
++    const size_t max_fds = G_N_ELEMENTS(vmsg->fds);
++    int *fds_t = NULL;
++    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
++    QIOChannel *ioc = server->ioc;
++
++    if (!ioc) {
++        error_report_err(local_err);
++        goto fail;
++    }
++
++    assert(qemu_in_coroutine());
++    do {
++        /*
++         * qio_channel_readv_full may have short reads, keeping calling it
++         * until getting VHOST_USER_HDR_SIZE or 0 bytes in total
++         */
++        rc = qio_channel_readv_full(ioc, &iov, 1, &fds_t, &nfds_t, &local_err);
++        if (rc < 0) {
++            if (rc == QIO_CHANNEL_ERR_BLOCK) {
++                qio_channel_yield(ioc, G_IO_IN);
++                continue;
++            } else {
++                error_report_err(local_err);
++                return false;
++            }
++        }
++        read_bytes += rc;
++        if (nfds_t > 0) {
++            if (nfds + nfds_t > max_fds) {
++                error_report("A maximum of %zu fds are allowed, "
++                             "however got %zu fds now",
++                             max_fds, nfds + nfds_t);
++                goto fail;
++            }
++            memcpy(vmsg->fds + nfds, fds_t,
++                   nfds_t *sizeof(vmsg->fds[0]));
++            nfds += nfds_t;
++            g_free(fds_t);
++        }
++        if (read_bytes == VHOST_USER_HDR_SIZE || rc == 0) {
++            break;
++        }
++        iov.iov_base = (char *)vmsg + read_bytes;
++        iov.iov_len = VHOST_USER_HDR_SIZE - read_bytes;
++    } while (true);
++
++    vmsg->fd_num = nfds;
++    /* qio_channel_readv_full will make socket fds blocking, unblock them */
++    vmsg_unblock_fds(vmsg);
++    if (vmsg->size > sizeof(vmsg->payload)) {
++        error_report("Error: too big message request: %d, "
++                     "size: vmsg->size: %u, "
++                     "while sizeof(vmsg->payload) = %zu",
++                     vmsg->request, vmsg->size, sizeof(vmsg->payload));
++        goto fail;
++    }
++
++    struct iovec iov_payload = {
++        .iov_base = (char *)&vmsg->payload,
++        .iov_len = vmsg->size,
++    };
++    if (vmsg->size) {
++        rc = qio_channel_readv_all_eof(ioc, &iov_payload, 1, &local_err);
++        if (rc == -1) {
++            error_report_err(local_err);
++            goto fail;
++        }
++    }
++
++    return true;
++
++fail:
++    vmsg_close_fds(vmsg);
++
++    return false;
++}
++
++
++static void vu_client_start(VuServer *server);
++static coroutine_fn void vu_client_trip(void *opaque)
++{
++    VuServer *server = opaque;
++
++    while (!server->aio_context_changed && server->sioc) {
++        server->processing_msg = true;
++        vu_dispatch(&server->vu_dev);
++        server->processing_msg = false;
++    }
++
++    if (server->aio_context_changed && server->sioc) {
++        server->aio_context_changed = false;
++        vu_client_start(server);
++    }
++}
++
++static void vu_client_start(VuServer *server)
++{
++    server->co_trip = qemu_coroutine_create(vu_client_trip, server);
++    aio_co_enter(server->ctx, server->co_trip);
++}
++
++/*
++ * a wrapper for vu_kick_cb
++ *
++ * since aio_dispatch can only pass one user data pointer to the
++ * callback function, pack VuDev and pvt into a struct. Then unpack it
++ * and pass them to vu_kick_cb
++ */
++static void kick_handler(void *opaque)
++{
++    VuFdWatch *vu_fd_watch = opaque;
++    vu_fd_watch->processing = true;
++    vu_fd_watch->cb(vu_fd_watch->vu_dev, 0, vu_fd_watch->pvt);
++    vu_fd_watch->processing = false;
++}
++
++
++static VuFdWatch *find_vu_fd_watch(VuServer *server, int fd)
++{
++
++    VuFdWatch *vu_fd_watch, *next;
++    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
++        if (vu_fd_watch->fd == fd) {
++            return vu_fd_watch;
++        }
++    }
++    return NULL;
++}
++
++static void
++set_watch(VuDev *vu_dev, int fd, int vu_evt,
++          vu_watch_cb cb, void *pvt)
++{
++
++    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
++    g_assert(vu_dev);
++    g_assert(fd >= 0);
++    g_assert(cb);
++
++    VuFdWatch *vu_fd_watch = find_vu_fd_watch(server, fd);
++
++    if (!vu_fd_watch) {
++        VuFdWatch *vu_fd_watch = g_new0(VuFdWatch, 1);
++
++        QTAILQ_INSERT_TAIL(&server->vu_fd_watches, vu_fd_watch, next);
++
++        vu_fd_watch->fd = fd;
++        vu_fd_watch->cb = cb;
++        qemu_set_nonblock(fd);
++        aio_set_fd_handler(server->ioc->ctx, fd, true, kick_handler,
++                           NULL, NULL, vu_fd_watch);
++        vu_fd_watch->vu_dev = vu_dev;
++        vu_fd_watch->pvt = pvt;
++    }
++}
++
++
++static void remove_watch(VuDev *vu_dev, int fd)
++{
++    VuServer *server;
++    g_assert(vu_dev);
++    g_assert(fd >= 0);
++
++    server = container_of(vu_dev, VuServer, vu_dev);
++
++    VuFdWatch *vu_fd_watch = find_vu_fd_watch(server, fd);
++
++    if (!vu_fd_watch) {
++        return;
++    }
++    aio_set_fd_handler(server->ioc->ctx, fd, true, NULL, NULL, NULL, NULL);
++
++    QTAILQ_REMOVE(&server->vu_fd_watches, vu_fd_watch, next);
++    g_free(vu_fd_watch);
++}
++
++
++static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
++                      gpointer opaque)
++{
++    VuServer *server = opaque;
++
++    if (server->sioc) {
++        warn_report("Only one vhost-user client is allowed to "
++                    "connect the server one time");
++        return;
++    }
++
++    if (!vu_init(&server->vu_dev, server->max_queues, sioc->fd, panic_cb,
++                 vu_message_read, set_watch, remove_watch, server->vu_iface)) {
++        error_report("Failed to initialize libvhost-user");
++        return;
++    }
++
++    /*
++     * Unset the callback function for network listener to make another
++     * vhost-user client keeping waiting until this client disconnects
++     */
++    qio_net_listener_set_client_func(server->listener,
++                                     NULL,
++                                     NULL,
++                                     NULL);
++    server->sioc = sioc;
++    /*
++     * Increase the object reference, so sioc will not freed by
++     * qio_net_listener_channel_func which will call object_unref(OBJECT(sioc))
++     */
++    object_ref(OBJECT(server->sioc));
++    qio_channel_set_name(QIO_CHANNEL(sioc), "vhost-user client");
++    server->ioc = QIO_CHANNEL(sioc);
++    object_ref(OBJECT(server->ioc));
++    qio_channel_attach_aio_context(server->ioc, server->ctx);
++    qio_channel_set_blocking(QIO_CHANNEL(server->sioc), false, NULL);
++    vu_client_start(server);
++}
++
++
++void vhost_user_server_stop(VuServer *server)
++{
++    if (server->sioc) {
++        close_client(server);
++    }
++
++    if (server->listener) {
++        qio_net_listener_disconnect(server->listener);
++        object_unref(OBJECT(server->listener));
++    }
++
++}
++
++void vhost_user_server_set_aio_context(VuServer *server, AioContext *ctx)
++{
++    VuFdWatch *vu_fd_watch, *next;
++    void *opaque = NULL;
++    IOHandler *io_read = NULL;
++    bool attach;
++
++    server->ctx = ctx ? ctx : qemu_get_aio_context();
++
++    if (!server->sioc) {
++        /* not yet serving any client*/
++        return;
++    }
++
++    if (ctx) {
++        qio_channel_attach_aio_context(server->ioc, ctx);
++        server->aio_context_changed = true;
++        io_read = kick_handler;
++        attach = true;
++    } else {
++        qio_channel_detach_aio_context(server->ioc);
++        /* server->ioc->ctx keeps the old AioConext */
++        ctx = server->ioc->ctx;
++        attach = false;
++    }
++
++    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
++        if (vu_fd_watch->cb) {
++            opaque = attach ? vu_fd_watch : NULL;
++            aio_set_fd_handler(ctx, vu_fd_watch->fd, true,
++                               io_read, NULL, NULL,
++                               opaque);
++        }
++    }
++}
++
++
++bool vhost_user_server_start(VuServer *server,
++                             SocketAddress *socket_addr,
++                             AioContext *ctx,
++                             uint16_t max_queues,
++                             DevicePanicNotifierFn *device_panic_notifier,
++                             const VuDevIface *vu_iface,
++                             Error **errp)
++{
++    QIONetListener *listener = qio_net_listener_new();
++    if (qio_net_listener_open_sync(listener, socket_addr, 1,
++                                   errp) < 0) {
++        object_unref(OBJECT(listener));
++        return false;
++    }
++
++    /* zero out unspecified fileds */
++    *server = (VuServer) {
++        .listener              = listener,
++        .vu_iface              = vu_iface,
++        .max_queues            = max_queues,
++        .ctx                   = ctx,
++        .device_panic_notifier = device_panic_notifier,
++    };
++
++    qio_net_listener_set_name(server->listener, "vhost-user-backend-listener");
++
++    qio_net_listener_set_client_func(server->listener,
++                                     vu_accept,
++                                     server,
++                                     NULL);
++
++    QTAILQ_INIT(&server->vu_fd_watches);
++    return true;
++}
+diff --git a/util/meson.build b/util/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/util/meson.build
++++ b/util/meson.build
+@@ -XXX,XX +XXX,XX @@ if have_block
+   util_ss.add(files('main-loop.c'))
+   util_ss.add(files('nvdimm-utils.c'))
+   util_ss.add(files('qemu-coroutine.c', 'qemu-coroutine-lock.c', 'qemu-coroutine-io.c'))
++  util_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-server.c'))
+   util_ss.add(files('qemu-coroutine-sleep.c'))
+   util_ss.add(files('qemu-co-shared-resource.c'))
+   util_ss.add(files('thread-pool.c', 'qemu-timer.c'))
+--
+.26.2

-[Qemu-devel] [PULL 01/12] util/iov: introduce qemu_iovec_init_extended
+[PULL v2 05/28] block: move logical block size check function to a common utility function
-From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+From: Coiby Xu <coiby.xu@gmail.com>
-Introduce new initialization API, to create requests with padding. Will
+Move the constants from hw/core/qdev-properties.c to
-be used in the following patch. New API uses qemu_iovec_init_buf if
+util/block-helpers.h so that knowledge of the min/max values is
 resulting io vector has only one element, to avoid extra allocations.
 So, we need to update qemu_iovec_destroy to support destroying such
 QIOVs.
-Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
+Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
-Message-id: 20190604161514.262241-2-vsementsov@virtuozzo.com
+Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Message-Id: <20190604161514.262241-2-vsementsov@virtuozzo.com>
+Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
 Acked-by: Eduardo Habkost <ehabkost@redhat.com>
 Message-id: 20200918080912.321299-5-coiby.xu@gmail.com
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- include/qemu/iov.h |   7 +++
+ util/block-helpers.h             | 19 +++++++++++++
- util/iov.c         | 112 +++++++++++++++++++++++++++++++++++++++++++--
+ hw/core/qdev-properties-system.c | 31 ++++-----------------
-files changed, 114 insertions(+), 5 deletions(-)
+ util/block-helpers.c             | 46 ++++++++++++++++++++++++++++++++
  util/meson.build                 |  1 +
 files changed, 71 insertions(+), 26 deletions(-)
  create mode 100644 util/block-helpers.h
  create mode 100644 util/block-helpers.c
-diff --git a/include/qemu/iov.h b/include/qemu/iov.h
+diff --git a/util/block-helpers.h b/util/block-helpers.h
 new file mode 100644
 index XXXXXXX..XXXXXXX
 --- /dev/null
 +++ b/util/block-helpers.h
@@ -XXX,XX +XXX,XX @@
 +#ifndef BLOCK_HELPERS_H
 +#define BLOCK_HELPERS_H
 +
 +#include "qemu/units.h"
 +
 +/* lower limit is sector size */
 +#define MIN_BLOCK_SIZE          INT64_C(512)
 +#define MIN_BLOCK_SIZE_STR      "512 B"
 +/*
 + * upper limit is arbitrary, 2 MiB looks sufficient for all sensible uses, and
 + * matches qcow2 cluster size limit
 + */
 +#define MAX_BLOCK_SIZE          (2 * MiB)
 +#define MAX_BLOCK_SIZE_STR      "2 MiB"
 +
 +void check_block_size(const char *id, const char *name, int64_t value,
 +                      Error **errp);
 +
 +#endif /* BLOCK_HELPERS_H */
 diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
 index XXXXXXX..XXXXXXX 100644
---- a/include/qemu/iov.h
+--- a/hw/core/qdev-properties-system.c
-+++ b/include/qemu/iov.h
++++ b/hw/core/qdev-properties-system.c
-@@ -XXX,XX +XXX,XX @@ static inline void *qemu_iovec_buf(QEMUIOVector *qiov)
+@@ -XXX,XX +XXX,XX @@
+ #include "sysemu/blockdev.h"
- void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint);
+ #include "net/net.h"
- void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov);
+ #include "hw/pci/pci.h"
-+void qemu_iovec_init_extended(
++#include "util/block-helpers.h"
-+        QEMUIOVector *qiov,
-+        void *head_buf, size_t head_len,
+ static bool check_prop_still_unset(DeviceState *dev, const char *name,
-+        QEMUIOVector *mid_qiov, size_t mid_offset, size_t mid_len,
+                                    const void *old_val, const char *new_val,
-+        void *tail_buf, size_t tail_len);
+@@ -XXX,XX +XXX,XX @@ const PropertyInfo qdev_prop_losttickpolicy = {
-+void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source,
-+                           size_t offset, size_t len);
+ /* --- blocksize --- */
- void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len);
- void qemu_iovec_concat(QEMUIOVector *dst,
+-/* lower limit is sector size */
-                        QEMUIOVector *src, size_t soffset, size_t sbytes);
+-#define MIN_BLOCK_SIZE          512
-diff --git a/util/iov.c b/util/iov.c
+-#define MIN_BLOCK_SIZE_STR      "512 B"
-index XXXXXXX..XXXXXXX 100644
+-/*
---- a/util/iov.c
+- * upper limit is arbitrary, 2 MiB looks sufficient for all sensible uses, and
-+++ b/util/iov.c
+- * matches qcow2 cluster size limit
-@@ -XXX,XX +XXX,XX @@ void qemu_iovec_concat(QEMUIOVector *dst,
+- */
-     qemu_iovec_concat_iov(dst, src->iov, src->niov, soffset, sbytes);
+-#define MAX_BLOCK_SIZE          (2 * MiB)
 -#define MAX_BLOCK_SIZE_STR      "2 MiB"
 -
  static void set_blocksize(Object *obj, Visitor *v, const char *name,
                            void *opaque, Error **errp)
  {
@@ -XXX,XX +XXX,XX @@ static void set_blocksize(Object *obj, Visitor *v, const char *name,
      Property *prop = opaque;
      uint32_t *ptr = qdev_get_prop_ptr(dev, prop);
      uint64_t value;
 +    Error *local_err = NULL;
      if (dev->realized) {
          qdev_prop_set_after_realize(dev, name, errp);
@@ -XXX,XX +XXX,XX @@ static void set_blocksize(Object *obj, Visitor *v, const char *name,
      if (!visit_type_size(v, name, &value, errp)) {
          return;
      }
 -    /* value of 0 means "unset" */
 -    if (value && (value < MIN_BLOCK_SIZE || value > MAX_BLOCK_SIZE)) {
 -        error_setg(errp,
 -                   "Property %s.%s doesn't take value %" PRIu64
 -                   " (minimum: " MIN_BLOCK_SIZE_STR
 -                   ", maximum: " MAX_BLOCK_SIZE_STR ")",
 -                   dev->id ? : "", name, value);
 +    check_block_size(dev->id ? : "", name, value, &local_err);
 +    if (local_err) {
 +        error_propagate(errp, local_err);
          return;
      }
 -
 -    /* We rely on power-of-2 blocksizes for bitmasks */
 -    if ((value & (value - 1)) != 0) {
 -        error_setg(errp,
 -                  "Property %s.%s doesn't take value '%" PRId64 "', "
 -                  "it's not a power of 2", dev->id ?: "", name, (int64_t)value);
 -        return;
 -    }
 -
      *ptr = value;
  }
+diff --git a/util/block-helpers.c b/util/block-helpers.c
+new file mode 100644
+index XXXXXXX..XXXXXXX
+--- /dev/null
++++ b/util/block-helpers.c
+@@ -XXX,XX +XXX,XX @@
 +/*
-+ * qiov_find_iov
++ * Block utility functions
 + *
-+ * Return pointer to iovec structure, where byte at @offset in original vector
++ * Copyright IBM, Corp. 2011
-+ * @iov exactly is.
++ * Copyright (c) 2020 Coiby Xu <coiby.xu@gmail.com>
-+ * Set @remaining_offset to be offset inside that iovec to the same byte.
++ *
 + * This work is licensed under the terms of the GNU GPL, version 2 or later.
 + * See the COPYING file in the top-level directory.
 + */
-+static struct iovec *iov_skip_offset(struct iovec *iov, size_t offset,
++
-+                                     size_t *remaining_offset)
++#include "qemu/osdep.h"
 +#include "qapi/error.h"
 +#include "qapi/qmp/qerror.h"
 +#include "block-helpers.h"
 +
 +/**
 + * check_block_size:
 + * @id: The unique ID of the object
 + * @name: The name of the property being validated
 + * @value: The block size in bytes
 + * @errp: A pointer to an area to store an error
 + *
 + * This function checks that the block size meets the following conditions:
 + * 1. At least MIN_BLOCK_SIZE
 + * 2. No larger than MAX_BLOCK_SIZE
 + * 3. A power of 2
 + */
 +void check_block_size(const char *id, const char *name, int64_t value,
 +                      Error **errp)
 +{
-+    while (offset > 0 && offset >= iov->iov_len) {
++    /* value of 0 means "unset" */
-+        offset -= iov->iov_len;
++    if (value && (value < MIN_BLOCK_SIZE || value > MAX_BLOCK_SIZE)) {
-+        iov++;
++        error_setg(errp, QERR_PROPERTY_VALUE_OUT_OF_RANGE,
-+    }
++                   id, name, value, MIN_BLOCK_SIZE, MAX_BLOCK_SIZE);
-+    *remaining_offset = offset;
++        return;
 +
 +    return iov;
 +}
 +
 +/*
 + * qiov_slice
 + *
 + * Find subarray of iovec's, containing requested range. @head would
 + * be offset in first iov (returned by the function), @tail would be
 + * count of extra bytes in last iovec (returned iov + @niov - 1).
 + */
 +static struct iovec *qiov_slice(QEMUIOVector *qiov,
 +                                size_t offset, size_t len,
 +                                size_t *head, size_t *tail, int *niov)
 +{
 +    struct iovec *iov, *end_iov;
 +
 +    assert(offset + len <= qiov->size);
 +
 +    iov = iov_skip_offset(qiov->iov, offset, head);
 +    end_iov = iov_skip_offset(iov, *head + len, tail);
 +
 +    if (*tail > 0) {
 +        assert(*tail < end_iov->iov_len);
 +        *tail = end_iov->iov_len - *tail;
 +        end_iov++;
 +    }
 +
-+    *niov = end_iov - iov;
++    /* We rely on power-of-2 blocksizes for bitmasks */
-+
++    if ((value & (value - 1)) != 0) {
-+    return iov;
++        error_setg(errp,
-+}
++                   "Property %s.%s doesn't take value '%" PRId64
-+
++                   "', it's not a power of 2",
-+/*
++                   id, name, value);
-+ * Compile new iovec, combining @head_buf buffer, sub-qiov of @mid_qiov,
++        return;
 + * and @tail_buf buffer into new qiov.
 + */
 +void qemu_iovec_init_extended(
 +        QEMUIOVector *qiov,
 +        void *head_buf, size_t head_len,
 +        QEMUIOVector *mid_qiov, size_t mid_offset, size_t mid_len,
 +        void *tail_buf, size_t tail_len)
 +{
 +    size_t mid_head, mid_tail;
 +    int total_niov, mid_niov = 0;
 +    struct iovec *p, *mid_iov;
 +
 +    if (mid_len) {
 +        mid_iov = qiov_slice(mid_qiov, mid_offset, mid_len,
 +                             &mid_head, &mid_tail, &mid_niov);
 +    }
 +
 +    total_niov = !!head_len + mid_niov + !!tail_len;
 +    if (total_niov == 1) {
 +        qemu_iovec_init_buf(qiov, NULL, 0);
 +        p = &qiov->local_iov;
 +    } else {
 +        qiov->niov = qiov->nalloc = total_niov;
 +        qiov->size = head_len + mid_len + tail_len;
 +        p = qiov->iov = g_new(struct iovec, qiov->niov);
 +    }
 +
 +    if (head_len) {
 +        p->iov_base = head_buf;
 +        p->iov_len = head_len;
 +        p++;
 +    }
 +
 +    if (mid_len) {
 +        memcpy(p, mid_iov, mid_niov * sizeof(*p));
 +        p[0].iov_base = (uint8_t *)p[0].iov_base + mid_head;
 +        p[0].iov_len -= mid_head;
 +        p[mid_niov - 1].iov_len -= mid_tail;
 +        p += mid_niov;
 +    }
 +
 +    if (tail_len) {
 +        p->iov_base = tail_buf;
 +        p->iov_len = tail_len;
 +    }
 +}
-+
+diff --git a/util/meson.build b/util/meson.build
- /*
+index XXXXXXX..XXXXXXX 100644
-  * Check if the contents of the iovecs are all zero
+--- a/util/meson.build
-  */
++++ b/util/meson.build
-@@ -XXX,XX +XXX,XX @@ bool qemu_iovec_is_zero(QEMUIOVector *qiov)
+@@ -XXX,XX +XXX,XX @@ if have_block
-     return true;
+   util_ss.add(files('nvdimm-utils.c'))
- }
+   util_ss.add(files('qemu-coroutine.c', 'qemu-coroutine-lock.c', 'qemu-coroutine-io.c'))
+   util_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-server.c'))
-+void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source,
++  util_ss.add(files('block-helpers.c'))
-+                           size_t offset, size_t len)
+   util_ss.add(files('qemu-coroutine-sleep.c'))
-+{
+   util_ss.add(files('qemu-co-shared-resource.c'))
-+    qemu_iovec_init_extended(qiov, NULL, 0, source, offset, len, NULL, 0);
+   util_ss.add(files('thread-pool.c', 'qemu-timer.c'))
 +}
 +
  void qemu_iovec_destroy(QEMUIOVector *qiov)
  {
 -    assert(qiov->nalloc != -1);
 +    if (qiov->nalloc != -1) {
 +        g_free(qiov->iov);
 +    }
 -    qemu_iovec_reset(qiov);
 -    g_free(qiov->iov);
 -    qiov->nalloc = 0;
 -    qiov->iov = NULL;
 +    memset(qiov, 0, sizeof(*qiov));
  }
  void qemu_iovec_reset(QEMUIOVector *qiov)
 --
-.21.0
+.26.2

-New patch
+[PULL v2 06/28] block/export: vhost-user block device backend server
+From: Coiby Xu <coiby.xu@gmail.com>
+By making use of libvhost-user, block device drive can be shared to
+the connected vhost-user client. Only one client can connect to the
+server one time.
+Since vhost-user-server needs a block drive to be created first, delay
+the creation of this object.
+Suggested-by: Kevin Wolf <kwolf@redhat.com>
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
+Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
+Message-id: 20200918080912.321299-6-coiby.xu@gmail.com
+[Shorten "vhost_user_blk_server" string to "vhost_user_blk" to avoid the
+following compiler warning:
+../block/export/vhost-user-blk-server.c:178:50: error: ‘%s’ directive output truncated writing 21 bytes into a region of size 20 [-Werror=format-truncation=]
+and fix "Invalid size %ld ..." ssize_t format string arguments for
+-bit hosts.
+--Stefan]
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ block/export/vhost-user-blk-server.h |  36 ++
+ block/export/vhost-user-blk-server.c | 661 +++++++++++++++++++++++++++
+ softmmu/vl.c                         |   4 +
+ block/meson.build                    |   1 +
+files changed, 702 insertions(+)
+ create mode 100644 block/export/vhost-user-blk-server.h
+ create mode 100644 block/export/vhost-user-blk-server.c
+diff --git a/block/export/vhost-user-blk-server.h b/block/export/vhost-user-blk-server.h
+new file mode 100644
+index XXXXXXX..XXXXXXX
+--- /dev/null
++++ b/block/export/vhost-user-blk-server.h
+@@ -XXX,XX +XXX,XX @@
++/*
++ * Sharing QEMU block devices via vhost-user protocal
++ *
++ * Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
++ * Copyright (c) 2020 Red Hat, Inc.
++ *
++ * This work is licensed under the terms of the GNU GPL, version 2 or
++ * later.  See the COPYING file in the top-level directory.
++ */
++
++#ifndef VHOST_USER_BLK_SERVER_H
++#define VHOST_USER_BLK_SERVER_H
++#include "util/vhost-user-server.h"
++
++typedef struct VuBlockDev VuBlockDev;
++#define TYPE_VHOST_USER_BLK_SERVER "vhost-user-blk-server"
++#define VHOST_USER_BLK_SERVER(obj) \
++   OBJECT_CHECK(VuBlockDev, obj, TYPE_VHOST_USER_BLK_SERVER)
++
++/* vhost user block device */
++struct VuBlockDev {
++    Object parent_obj;
++    char *node_name;
++    SocketAddress *addr;
++    AioContext *ctx;
++    VuServer vu_server;
++    bool running;
++    uint32_t blk_size;
++    BlockBackend *backend;
++    QIOChannelSocket *sioc;
++    QTAILQ_ENTRY(VuBlockDev) next;
++    struct virtio_blk_config blkcfg;
++    bool writable;
++};
++
++#endif /* VHOST_USER_BLK_SERVER_H */
+diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
+new file mode 100644
+index XXXXXXX..XXXXXXX
+--- /dev/null
++++ b/block/export/vhost-user-blk-server.c
+@@ -XXX,XX +XXX,XX @@
++/*
++ * Sharing QEMU block devices via vhost-user protocal
++ *
++ * Parts of the code based on nbd/server.c.
++ *
++ * Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
++ * Copyright (c) 2020 Red Hat, Inc.
++ *
++ * This work is licensed under the terms of the GNU GPL, version 2 or
++ * later.  See the COPYING file in the top-level directory.
++ */
++#include "qemu/osdep.h"
++#include "block/block.h"
++#include "vhost-user-blk-server.h"
++#include "qapi/error.h"
++#include "qom/object_interfaces.h"
++#include "sysemu/block-backend.h"
++#include "util/block-helpers.h"
++
++enum {
++    VHOST_USER_BLK_MAX_QUEUES = 1,
++};
++struct virtio_blk_inhdr {
++    unsigned char status;
++};
++
++typedef struct VuBlockReq {
++    VuVirtqElement *elem;
++    int64_t sector_num;
++    size_t size;
++    struct virtio_blk_inhdr *in;
++    struct virtio_blk_outhdr out;
++    VuServer *server;
++    struct VuVirtq *vq;
++} VuBlockReq;
++
++static void vu_block_req_complete(VuBlockReq *req)
++{
++    VuDev *vu_dev = &req->server->vu_dev;
++
++    /* IO size with 1 extra status byte */
++    vu_queue_push(vu_dev, req->vq, req->elem, req->size + 1);
++    vu_queue_notify(vu_dev, req->vq);
++
++    if (req->elem) {
++        free(req->elem);
++    }
++
++    g_free(req);
++}
++
++static VuBlockDev *get_vu_block_device_by_server(VuServer *server)
++{
++    return container_of(server, VuBlockDev, vu_server);
++}
++
++static int coroutine_fn
++vu_block_discard_write_zeroes(VuBlockReq *req, struct iovec *iov,
++                              uint32_t iovcnt, uint32_t type)
++{
++    struct virtio_blk_discard_write_zeroes desc;
++    ssize_t size = iov_to_buf(iov, iovcnt, 0, &desc, sizeof(desc));
++    if (unlikely(size != sizeof(desc))) {
++        error_report("Invalid size %zd, expect %zu", size, sizeof(desc));
++        return -EINVAL;
++    }
++
++    VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server);
++    uint64_t range[2] = { le64_to_cpu(desc.sector) << 9,
++                          le32_to_cpu(desc.num_sectors) << 9 };
++    if (type == VIRTIO_BLK_T_DISCARD) {
++        if (blk_co_pdiscard(vdev_blk->backend, range[0], range[1]) == 0) {
++            return 0;
++        }
++    } else if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
++        if (blk_co_pwrite_zeroes(vdev_blk->backend,
++                                 range[0], range[1], 0) == 0) {
++            return 0;
++        }
++    }
++
++    return -EINVAL;
++}
++
++static void coroutine_fn vu_block_flush(VuBlockReq *req)
++{
++    VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server);
++    BlockBackend *backend = vdev_blk->backend;
++    blk_co_flush(backend);
++}
++
++struct req_data {
++    VuServer *server;
++    VuVirtq *vq;
++    VuVirtqElement *elem;
++};
++
++static void coroutine_fn vu_block_virtio_process_req(void *opaque)
++{
++    struct req_data *data = opaque;
++    VuServer *server = data->server;
++    VuVirtq *vq = data->vq;
++    VuVirtqElement *elem = data->elem;
++    uint32_t type;
++    VuBlockReq *req;
++
++    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
++    BlockBackend *backend = vdev_blk->backend;
++
++    struct iovec *in_iov = elem->in_sg;
++    struct iovec *out_iov = elem->out_sg;
++    unsigned in_num = elem->in_num;
++    unsigned out_num = elem->out_num;
++    /* refer to hw/block/virtio_blk.c */
++    if (elem->out_num < 1 || elem->in_num < 1) {
++        error_report("virtio-blk request missing headers");
++        free(elem);
++        return;
++    }
++
++    req = g_new0(VuBlockReq, 1);
++    req->server = server;
++    req->vq = vq;
++    req->elem = elem;
++
++    if (unlikely(iov_to_buf(out_iov, out_num, 0, &req->out,
++                            sizeof(req->out)) != sizeof(req->out))) {
++        error_report("virtio-blk request outhdr too short");
++        goto err;
++    }
++
++    iov_discard_front(&out_iov, &out_num, sizeof(req->out));
++
++    if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) {
++        error_report("virtio-blk request inhdr too short");
++        goto err;
++    }
++
++    /* We always touch the last byte, so just see how big in_iov is.  */
++    req->in = (void *)in_iov[in_num - 1].iov_base
++              + in_iov[in_num - 1].iov_len
++              - sizeof(struct virtio_blk_inhdr);
++    iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr));
++
++    type = le32_to_cpu(req->out.type);
++    switch (type & ~VIRTIO_BLK_T_BARRIER) {
++    case VIRTIO_BLK_T_IN:
++    case VIRTIO_BLK_T_OUT: {
++        ssize_t ret = 0;
++        bool is_write = type & VIRTIO_BLK_T_OUT;
++        req->sector_num = le64_to_cpu(req->out.sector);
++
++        int64_t offset = req->sector_num * vdev_blk->blk_size;
++        QEMUIOVector qiov;
++        if (is_write) {
++            qemu_iovec_init_external(&qiov, out_iov, out_num);
++            ret = blk_co_pwritev(backend, offset, qiov.size,
++                                 &qiov, 0);
++        } else {
++            qemu_iovec_init_external(&qiov, in_iov, in_num);
++            ret = blk_co_preadv(backend, offset, qiov.size,
++                                &qiov, 0);
++        }
++        if (ret >= 0) {
++            req->in->status = VIRTIO_BLK_S_OK;
++        } else {
++            req->in->status = VIRTIO_BLK_S_IOERR;
++        }
++        break;
++    }
++    case VIRTIO_BLK_T_FLUSH:
++        vu_block_flush(req);
++        req->in->status = VIRTIO_BLK_S_OK;
++        break;
++    case VIRTIO_BLK_T_GET_ID: {
++        size_t size = MIN(iov_size(&elem->in_sg[0], in_num),
++                          VIRTIO_BLK_ID_BYTES);
++        snprintf(elem->in_sg[0].iov_base, size, "%s", "vhost_user_blk");
++        req->in->status = VIRTIO_BLK_S_OK;
++        req->size = elem->in_sg[0].iov_len;
++        break;
++    }
++    case VIRTIO_BLK_T_DISCARD:
++    case VIRTIO_BLK_T_WRITE_ZEROES: {
++        int rc;
++        rc = vu_block_discard_write_zeroes(req, &elem->out_sg[1],
++                                           out_num, type);
++        if (rc == 0) {
++            req->in->status = VIRTIO_BLK_S_OK;
++        } else {
++            req->in->status = VIRTIO_BLK_S_IOERR;
++        }
++        break;
++    }
++    default:
++        req->in->status = VIRTIO_BLK_S_UNSUPP;
++        break;
++    }
++
++    vu_block_req_complete(req);
++    return;
++
++err:
++    free(elem);
++    g_free(req);
++    return;
++}
++
++static void vu_block_process_vq(VuDev *vu_dev, int idx)
++{
++    VuServer *server;
++    VuVirtq *vq;
++    struct req_data *req_data;
++
++    server = container_of(vu_dev, VuServer, vu_dev);
++    assert(server);
++
++    vq = vu_get_queue(vu_dev, idx);
++    assert(vq);
++    VuVirtqElement *elem;
++    while (1) {
++        elem = vu_queue_pop(vu_dev, vq, sizeof(VuVirtqElement) +
++                                    sizeof(VuBlockReq));
++        if (elem) {
++            req_data = g_new0(struct req_data, 1);
++            req_data->server = server;
++            req_data->vq = vq;
++            req_data->elem = elem;
++            Coroutine *co = qemu_coroutine_create(vu_block_virtio_process_req,
++                                                  req_data);
++            aio_co_enter(server->ioc->ctx, co);
++        } else {
++            break;
++        }
++    }
++}
++
++static void vu_block_queue_set_started(VuDev *vu_dev, int idx, bool started)
++{
++    VuVirtq *vq;
++
++    assert(vu_dev);
++
++    vq = vu_get_queue(vu_dev, idx);
++    vu_set_queue_handler(vu_dev, vq, started ? vu_block_process_vq : NULL);
++}
++
++static uint64_t vu_block_get_features(VuDev *dev)
++{
++    uint64_t features;
++    VuServer *server = container_of(dev, VuServer, vu_dev);
++    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
++    features = 1ull << VIRTIO_BLK_F_SIZE_MAX |
++               1ull << VIRTIO_BLK_F_SEG_MAX |
++               1ull << VIRTIO_BLK_F_TOPOLOGY |
++               1ull << VIRTIO_BLK_F_BLK_SIZE |
++               1ull << VIRTIO_BLK_F_FLUSH |
++               1ull << VIRTIO_BLK_F_DISCARD |
++               1ull << VIRTIO_BLK_F_WRITE_ZEROES |
++               1ull << VIRTIO_BLK_F_CONFIG_WCE |
++               1ull << VIRTIO_F_VERSION_1 |
++               1ull << VIRTIO_RING_F_INDIRECT_DESC |
++               1ull << VIRTIO_RING_F_EVENT_IDX |
++               1ull << VHOST_USER_F_PROTOCOL_FEATURES;
++
++    if (!vdev_blk->writable) {
++        features |= 1ull << VIRTIO_BLK_F_RO;
++    }
++
++    return features;
++}
++
++static uint64_t vu_block_get_protocol_features(VuDev *dev)
++{
++    return 1ull << VHOST_USER_PROTOCOL_F_CONFIG |
++           1ull << VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD;
++}
++
++static int
++vu_block_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
++{
++    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
++    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
++    memcpy(config, &vdev_blk->blkcfg, len);
++
++    return 0;
++}
++
++static int
++vu_block_set_config(VuDev *vu_dev, const uint8_t *data,
++                    uint32_t offset, uint32_t size, uint32_t flags)
++{
++    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
++    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
++    uint8_t wce;
++
++    /* don't support live migration */
++    if (flags != VHOST_SET_CONFIG_TYPE_MASTER) {
++        return -EINVAL;
++    }
++
++    if (offset != offsetof(struct virtio_blk_config, wce) ||
++        size != 1) {
++        return -EINVAL;
++    }
++
++    wce = *data;
++    vdev_blk->blkcfg.wce = wce;
++    blk_set_enable_write_cache(vdev_blk->backend, wce);
++    return 0;
++}
++
++/*
++ * When the client disconnects, it sends a VHOST_USER_NONE request
++ * and vu_process_message will simple call exit which cause the VM
++ * to exit abruptly.
++ * To avoid this issue,  process VHOST_USER_NONE request ahead
++ * of vu_process_message.
++ *
++ */
++static int vu_block_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
++{
++    if (vmsg->request == VHOST_USER_NONE) {
++        dev->panic(dev, "disconnect");
++        return true;
++    }
++    return false;
++}
++
++static const VuDevIface vu_block_iface = {
++    .get_features          = vu_block_get_features,
++    .queue_set_started     = vu_block_queue_set_started,
++    .get_protocol_features = vu_block_get_protocol_features,
++    .get_config            = vu_block_get_config,
++    .set_config            = vu_block_set_config,
++    .process_msg           = vu_block_process_msg,
++};
++
++static void blk_aio_attached(AioContext *ctx, void *opaque)
++{
++    VuBlockDev *vub_dev = opaque;
++    aio_context_acquire(ctx);
++    vhost_user_server_set_aio_context(&vub_dev->vu_server, ctx);
++    aio_context_release(ctx);
++}
++
++static void blk_aio_detach(void *opaque)
++{
++    VuBlockDev *vub_dev = opaque;
++    AioContext *ctx = vub_dev->vu_server.ctx;
++    aio_context_acquire(ctx);
++    vhost_user_server_set_aio_context(&vub_dev->vu_server, NULL);
++    aio_context_release(ctx);
++}
++
++static void
++vu_block_initialize_config(BlockDriverState *bs,
++                           struct virtio_blk_config *config, uint32_t blk_size)
++{
++    config->capacity = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
++    config->blk_size = blk_size;
++    config->size_max = 0;
++    config->seg_max = 128 - 2;
++    config->min_io_size = 1;
++    config->opt_io_size = 1;
++    config->num_queues = VHOST_USER_BLK_MAX_QUEUES;
++    config->max_discard_sectors = 32768;
++    config->max_discard_seg = 1;
++    config->discard_sector_alignment = config->blk_size >> 9;
++    config->max_write_zeroes_sectors = 32768;
++    config->max_write_zeroes_seg = 1;
++}
++
++static VuBlockDev *vu_block_init(VuBlockDev *vu_block_device, Error **errp)
++{
++
++    BlockBackend *blk;
++    Error *local_error = NULL;
++    const char *node_name = vu_block_device->node_name;
++    bool writable = vu_block_device->writable;
++    uint64_t perm = BLK_PERM_CONSISTENT_READ;
++    int ret;
++
++    AioContext *ctx;
++
++    BlockDriverState *bs = bdrv_lookup_bs(node_name, node_name, &local_error);
++
++    if (!bs) {
++        error_propagate(errp, local_error);
++        return NULL;
++    }
++
++    if (bdrv_is_read_only(bs)) {
++        writable = false;
++    }
++
++    if (writable) {
++        perm |= BLK_PERM_WRITE;
++    }
++
++    ctx = bdrv_get_aio_context(bs);
++    aio_context_acquire(ctx);
++    bdrv_invalidate_cache(bs, NULL);
++    aio_context_release(ctx);
++
++    /*
++     * Don't allow resize while the vhost user server is running,
++     * otherwise we don't care what happens with the node.
++     */
++    blk = blk_new(bdrv_get_aio_context(bs), perm,
++                  BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
++                  BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
++    ret = blk_insert_bs(blk, bs, errp);
++
++    if (ret < 0) {
++        goto fail;
++    }
++
++    blk_set_enable_write_cache(blk, false);
++
++    blk_set_allow_aio_context_change(blk, true);
++
++    vu_block_device->blkcfg.wce = 0;
++    vu_block_device->backend = blk;
++    if (!vu_block_device->blk_size) {
++        vu_block_device->blk_size = BDRV_SECTOR_SIZE;
++    }
++    vu_block_device->blkcfg.blk_size = vu_block_device->blk_size;
++    blk_set_guest_block_size(blk, vu_block_device->blk_size);
++    vu_block_initialize_config(bs, &vu_block_device->blkcfg,
++                                   vu_block_device->blk_size);
++    return vu_block_device;
++
++fail:
++    blk_unref(blk);
++    return NULL;
++}
++
++static void vu_block_deinit(VuBlockDev *vu_block_device)
++{
++    if (vu_block_device->backend) {
++        blk_remove_aio_context_notifier(vu_block_device->backend, blk_aio_attached,
++                                        blk_aio_detach, vu_block_device);
++    }
++
++    blk_unref(vu_block_device->backend);
++}
++
++static void vhost_user_blk_server_stop(VuBlockDev *vu_block_device)
++{
++    vhost_user_server_stop(&vu_block_device->vu_server);
++    vu_block_deinit(vu_block_device);
++}
++
++static void vhost_user_blk_server_start(VuBlockDev *vu_block_device,
++                                        Error **errp)
++{
++    AioContext *ctx;
++    SocketAddress *addr = vu_block_device->addr;
++
++    if (!vu_block_init(vu_block_device, errp)) {
++        return;
++    }
++
++    ctx = bdrv_get_aio_context(blk_bs(vu_block_device->backend));
++
++    if (!vhost_user_server_start(&vu_block_device->vu_server, addr, ctx,
++                                 VHOST_USER_BLK_MAX_QUEUES,
++                                 NULL, &vu_block_iface,
++                                 errp)) {
++        goto error;
++    }
++
++    blk_add_aio_context_notifier(vu_block_device->backend, blk_aio_attached,
++                                 blk_aio_detach, vu_block_device);
++    vu_block_device->running = true;
++    return;
++
++ error:
++    vu_block_deinit(vu_block_device);
++}
++
++static bool vu_prop_modifiable(VuBlockDev *vus, Error **errp)
++{
++    if (vus->running) {
++            error_setg(errp, "The property can't be modified "
++                       "while the server is running");
++            return false;
++    }
++    return true;
++}
++
++static void vu_set_node_name(Object *obj, const char *value, Error **errp)
++{
++    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
++
++    if (!vu_prop_modifiable(vus, errp)) {
++        return;
++    }
++
++    if (vus->node_name) {
++        g_free(vus->node_name);
++    }
++
++    vus->node_name = g_strdup(value);
++}
++
++static char *vu_get_node_name(Object *obj, Error **errp)
++{
++    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
++    return g_strdup(vus->node_name);
++}
++
++static void free_socket_addr(SocketAddress *addr)
++{
++        g_free(addr->u.q_unix.path);
++        g_free(addr);
++}
++
++static void vu_set_unix_socket(Object *obj, const char *value,
++                               Error **errp)
++{
++    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
++
++    if (!vu_prop_modifiable(vus, errp)) {
++        return;
++    }
++
++    if (vus->addr) {
++        free_socket_addr(vus->addr);
++    }
++
++    SocketAddress *addr = g_new0(SocketAddress, 1);
++    addr->type = SOCKET_ADDRESS_TYPE_UNIX;
++    addr->u.q_unix.path = g_strdup(value);
++    vus->addr = addr;
++}
++
++static char *vu_get_unix_socket(Object *obj, Error **errp)
++{
++    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
++    return g_strdup(vus->addr->u.q_unix.path);
++}
++
++static bool vu_get_block_writable(Object *obj, Error **errp)
++{
++    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
++    return vus->writable;
++}
++
++static void vu_set_block_writable(Object *obj, bool value, Error **errp)
++{
++    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
++
++    if (!vu_prop_modifiable(vus, errp)) {
++            return;
++    }
++
++    vus->writable = value;
++}
++
++static void vu_get_blk_size(Object *obj, Visitor *v, const char *name,
++                            void *opaque, Error **errp)
++{
++    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
++    uint32_t value = vus->blk_size;
++
++    visit_type_uint32(v, name, &value, errp);
++}
++
++static void vu_set_blk_size(Object *obj, Visitor *v, const char *name,
++                            void *opaque, Error **errp)
++{
++    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
++
++    Error *local_err = NULL;
++    uint32_t value;
++
++    if (!vu_prop_modifiable(vus, errp)) {
++            return;
++    }
++
++    visit_type_uint32(v, name, &value, &local_err);
++    if (local_err) {
++        goto out;
++    }
++
++    check_block_size(object_get_typename(obj), name, value, &local_err);
++    if (local_err) {
++        goto out;
++    }
++
++    vus->blk_size = value;
++
++out:
++    error_propagate(errp, local_err);
++}
++
++static void vhost_user_blk_server_instance_finalize(Object *obj)
++{
++    VuBlockDev *vub = VHOST_USER_BLK_SERVER(obj);
++
++    vhost_user_blk_server_stop(vub);
++
++    /*
++     * Unlike object_property_add_str, object_class_property_add_str
++     * doesn't have a release method. Thus manual memory freeing is
++     * needed.
++     */
++    free_socket_addr(vub->addr);
++    g_free(vub->node_name);
++}
++
++static void vhost_user_blk_server_complete(UserCreatable *obj, Error **errp)
++{
++    VuBlockDev *vub = VHOST_USER_BLK_SERVER(obj);
++
++    vhost_user_blk_server_start(vub, errp);
++}
++
++static void vhost_user_blk_server_class_init(ObjectClass *klass,
++                                             void *class_data)
++{
++    UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
++    ucc->complete = vhost_user_blk_server_complete;
++
++    object_class_property_add_bool(klass, "writable",
++                                   vu_get_block_writable,
++                                   vu_set_block_writable);
++
++    object_class_property_add_str(klass, "node-name",
++                                  vu_get_node_name,
++                                  vu_set_node_name);
++
++    object_class_property_add_str(klass, "unix-socket",
++                                  vu_get_unix_socket,
++                                  vu_set_unix_socket);
++
++    object_class_property_add(klass, "logical-block-size", "uint32",
++                              vu_get_blk_size, vu_set_blk_size,
++                              NULL, NULL);
++}
++
++static const TypeInfo vhost_user_blk_server_info = {
++    .name = TYPE_VHOST_USER_BLK_SERVER,
++    .parent = TYPE_OBJECT,
++    .instance_size = sizeof(VuBlockDev),
++    .instance_finalize = vhost_user_blk_server_instance_finalize,
++    .class_init = vhost_user_blk_server_class_init,
++    .interfaces = (InterfaceInfo[]) {
++        {TYPE_USER_CREATABLE},
++        {}
++    },
++};
++
++static void vhost_user_blk_server_register_types(void)
++{
++    type_register_static(&vhost_user_blk_server_info);
++}
++
++type_init(vhost_user_blk_server_register_types)
+diff --git a/softmmu/vl.c b/softmmu/vl.c
+index XXXXXXX..XXXXXXX 100644
+--- a/softmmu/vl.c
++++ b/softmmu/vl.c
+@@ -XXX,XX +XXX,XX @@ static bool object_create_initial(const char *type, QemuOpts *opts)
+     }
+ #endif
++    /* Reason: vhost-user-blk-server property "node-name" */
++    if (g_str_equal(type, "vhost-user-blk-server")) {
++        return false;
++    }
+     /*
+      * Reason: filter-* property "netdev" etc.
+      */
+diff --git a/block/meson.build b/block/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/block/meson.build
++++ b/block/meson.build
+@@ -XXX,XX +XXX,XX @@ block_ss.add(when: 'CONFIG_WIN32', if_true: files('file-win32.c', 'win32-aio.c')
+ block_ss.add(when: 'CONFIG_POSIX', if_true: [files('file-posix.c'), coref, iokit])
+ block_ss.add(when: 'CONFIG_LIBISCSI', if_true: files('iscsi-opts.c'))
+ block_ss.add(when: 'CONFIG_LINUX', if_true: files('nvme.c'))
++block_ss.add(when: 'CONFIG_LINUX', if_true: files('export/vhost-user-blk-server.c', '../contrib/libvhost-user/libvhost-user.c'))
+ block_ss.add(when: 'CONFIG_REPLICATION', if_true: files('replication.c'))
+ block_ss.add(when: 'CONFIG_SHEEPDOG', if_true: files('sheepdog.c'))
+ block_ss.add(when: ['CONFIG_LINUX_AIO', libaio], if_true: files('linux-aio.c'))
+--
+.26.2

-New patch
+[PULL v2 07/28] MAINTAINERS: Add vhost-user block device backend server maintainer
+From: Coiby Xu <coiby.xu@gmail.com>
+Suggested-by: Stefano Garzarella <sgarzare@redhat.com>
+Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
+Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
+Message-id: 20200918080912.321299-8-coiby.xu@gmail.com
+[Removed reference to vhost-user-blk-test.c, it will be sent in a
+separate pull request.
+--Stefan]
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ MAINTAINERS | 7 +++++++
+file changed, 7 insertions(+)
+diff --git a/MAINTAINERS b/MAINTAINERS
+index XXXXXXX..XXXXXXX 100644
+--- a/MAINTAINERS
++++ b/MAINTAINERS
+@@ -XXX,XX +XXX,XX @@ L: qemu-block@nongnu.org
+ S: Supported
+ F: tests/image-fuzzer/
++Vhost-user block device backend server
++M: Coiby Xu <Coiby.Xu@gmail.com>
++S: Maintained
++F: block/export/vhost-user-blk-server.c
++F: util/vhost-user-server.c
++F: tests/qtest/libqos/vhost-user-blk.c
++
+ Replication
+ M: Wen Congyang <wencongyang2@huawei.com>
+ M: Xie Changlong <xiechanglong.d@gmail.com>
+--
+.26.2

-New patch
+[PULL v2 08/28] util/vhost-user-server: s/fileds/fields/ typo fix
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200924151549.913737-3-stefanha@redhat.com
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ util/vhost-user-server.c | 2 +-
+file changed, 1 insertion(+), 1 deletion(-)
+diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/util/vhost-user-server.c
++++ b/util/vhost-user-server.c
+@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
+         return false;
+     }
+-    /* zero out unspecified fileds */
++    /* zero out unspecified fields */
+     *server = (VuServer) {
+         .listener              = listener,
+         .vu_iface              = vu_iface,
+--
+.26.2

-New patch
+[PULL v2 09/28] util/vhost-user-server: drop unnecessary QOM cast
+We already have access to the value with the correct type (ioc and sioc
+are the same QIOChannel).
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200924151549.913737-4-stefanha@redhat.com
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ util/vhost-user-server.c | 2 +-
+file changed, 1 insertion(+), 1 deletion(-)
+diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/util/vhost-user-server.c
++++ b/util/vhost-user-server.c
+@@ -XXX,XX +XXX,XX @@ static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
+     server->ioc = QIO_CHANNEL(sioc);
+     object_ref(OBJECT(server->ioc));
+     qio_channel_attach_aio_context(server->ioc, server->ctx);
+-    qio_channel_set_blocking(QIO_CHANNEL(server->sioc), false, NULL);
++    qio_channel_set_blocking(server->ioc, false, NULL);
+     vu_client_start(server);
+ }
+--
+.26.2

-[Qemu-devel] [PULL 03/12] block/io: refactor padding
+[PULL v2 10/28] util/vhost-user-server: drop unnecessary watch deletion
-From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+Explicitly deleting watches is not necessary since libvhost-user calls
 remove_watch() during vu_deinit(). Add an assertion to check this
 though.
-We have similar padding code in bdrv_co_pwritev,
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-bdrv_co_do_pwrite_zeroes and bdrv_co_preadv. Let's combine and unify
+Message-id: 20200924151549.913737-5-stefanha@redhat.com
 it.
 [Squashed in Vladimir's qemu-iotests 077 fix
 --Stefan]
 Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
 Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
 Message-id: 20190604161514.262241-4-vsementsov@virtuozzo.com
 Message-Id: <20190604161514.262241-4-vsementsov@virtuozzo.com>
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- block/io.c | 365 +++++++++++++++++++++++++++++------------------------
+ util/vhost-user-server.c | 19 ++++---------------
-file changed, 200 insertions(+), 165 deletions(-)
+file changed, 4 insertions(+), 15 deletions(-)
-diff --git a/block/io.c b/block/io.c
+diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
 index XXXXXXX..XXXXXXX 100644
---- a/block/io.c
+--- a/util/vhost-user-server.c
-+++ b/block/io.c
++++ b/util/vhost-user-server.c
-@@ -XXX,XX +XXX,XX @@ out:
+@@ -XXX,XX +XXX,XX @@ static void close_client(VuServer *server)
- }
+     /* When this is set vu_client_trip will stop new processing vhost-user message */
+     server->sioc = NULL;
- /*
-- * Handle a read request in coroutine context
+-    VuFdWatch *vu_fd_watch, *next;
-+ * Request padding
+-    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
-+ *
+-        aio_set_fd_handler(server->ioc->ctx, vu_fd_watch->fd, true, NULL,
-+ *  |<---- align ----->|                     |<----- align ---->|
+-                           NULL, NULL, NULL);
 + *  |<- head ->|<------------- bytes ------------->|<-- tail -->|
 + *  |          |       |                     |     |            |
 + * -*----------$-------*-------- ... --------*-----$------------*---
 + *  |          |       |                     |     |            |
 + *  |          offset  |                     |     end          |
 + *  ALIGN_DOWN(offset) ALIGN_UP(offset)      ALIGN_DOWN(end)   ALIGN_UP(end)
 + *  [buf   ... )                             [tail_buf          )
 + *
 + * @buf is an aligned allocation needed to store @head and @tail paddings. @head
 + * is placed at the beginning of @buf and @tail at the @end.
 + *
 + * @tail_buf is a pointer to sub-buffer, corresponding to align-sized chunk
 + * around tail, if tail exists.
 + *
 + * @merge_reads is true for small requests,
 + * if @buf_len == @head + bytes + @tail. In this case it is possible that both
 + * head and tail exist but @buf_len == align and @tail_buf == @buf.
   */
 +typedef struct BdrvRequestPadding {
 +    uint8_t *buf;
 +    size_t buf_len;
 +    uint8_t *tail_buf;
 +    size_t head;
 +    size_t tail;
 +    bool merge_reads;
 +    QEMUIOVector local_qiov;
 +} BdrvRequestPadding;
 +
 +static bool bdrv_init_padding(BlockDriverState *bs,
 +                              int64_t offset, int64_t bytes,
 +                              BdrvRequestPadding *pad)
 +{
 +    uint64_t align = bs->bl.request_alignment;
 +    size_t sum;
 +
 +    memset(pad, 0, sizeof(*pad));
 +
 +    pad->head = offset & (align - 1);
 +    pad->tail = ((offset + bytes) & (align - 1));
 +    if (pad->tail) {
 +        pad->tail = align - pad->tail;
 +    }
 +
 +    if ((!pad->head && !pad->tail) || !bytes) {
 +        return false;
 +    }
 +
 +    sum = pad->head + bytes + pad->tail;
 +    pad->buf_len = (sum > align && pad->head && pad->tail) ? 2 * align : align;
 +    pad->buf = qemu_blockalign(bs, pad->buf_len);
 +    pad->merge_reads = sum == pad->buf_len;
 +    if (pad->tail) {
 +        pad->tail_buf = pad->buf + pad->buf_len - align;
 +    }
 +
 +    return true;
 +}
 +
 +static int bdrv_padding_rmw_read(BdrvChild *child,
 +                                 BdrvTrackedRequest *req,
 +                                 BdrvRequestPadding *pad,
 +                                 bool zero_middle)
 +{
 +    QEMUIOVector local_qiov;
 +    BlockDriverState *bs = child->bs;
 +    uint64_t align = bs->bl.request_alignment;
 +    int ret;
 +
 +    assert(req->serialising && pad->buf);
 +
 +    if (pad->head || pad->merge_reads) {
 +        uint64_t bytes = pad->merge_reads ? pad->buf_len : align;
 +
 +        qemu_iovec_init_buf(&local_qiov, pad->buf, bytes);
 +
 +        if (pad->head) {
 +            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
 +        }
 +        if (pad->merge_reads && pad->tail) {
 +            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
 +        }
 +        ret = bdrv_aligned_preadv(child, req, req->overlap_offset, bytes,
 +                                  align, &local_qiov, 0);
 +        if (ret < 0) {
 +            return ret;
 +        }
 +        if (pad->head) {
 +            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
 +        }
 +        if (pad->merge_reads && pad->tail) {
 +            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
 +        }
 +
 +        if (pad->merge_reads) {
 +            goto zero_mem;
 +        }
 +    }
 +
 +    if (pad->tail) {
 +        qemu_iovec_init_buf(&local_qiov, pad->tail_buf, align);
 +
 +        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
 +        ret = bdrv_aligned_preadv(
 +                child, req,
 +                req->overlap_offset + req->overlap_bytes - align,
 +                align, align, &local_qiov, 0);
 +        if (ret < 0) {
 +            return ret;
 +        }
 +        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
 +    }
 +
 +zero_mem:
 +    if (zero_middle) {
 +        memset(pad->buf + pad->head, 0, pad->buf_len - pad->head - pad->tail);
 +    }
 +
 +    return 0;
 +}
 +
 +static void bdrv_padding_destroy(BdrvRequestPadding *pad)
 +{
 +    if (pad->buf) {
 +        qemu_vfree(pad->buf);
 +        qemu_iovec_destroy(&pad->local_qiov);
 +    }
 +}
 +
 +/*
 + * bdrv_pad_request
 + *
 + * Exchange request parameters with padded request if needed. Don't include RMW
 + * read of padding, bdrv_padding_rmw_read() should be called separately if
 + * needed.
 + *
 + * All parameters except @bs are in-out: they represent original request at
 + * function call and padded (if padding needed) at function finish.
 + *
 + * Function always succeeds.
 + */
 +static bool bdrv_pad_request(BlockDriverState *bs, QEMUIOVector **qiov,
 +                             int64_t *offset, unsigned int *bytes,
 +                             BdrvRequestPadding *pad)
 +{
 +    if (!bdrv_init_padding(bs, *offset, *bytes, pad)) {
 +        return false;
 +    }
 +
 +    qemu_iovec_init_extended(&pad->local_qiov, pad->buf, pad->head,
 +                             *qiov, 0, *bytes,
 +                             pad->buf + pad->buf_len - pad->tail, pad->tail);
 +    *bytes += pad->head + pad->tail;
 +    *offset -= pad->head;
 +    *qiov = &pad->local_qiov;
 +
 +    return true;
 +}
 +
  int coroutine_fn bdrv_co_preadv(BdrvChild *child,
      int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
      BdrvRequestFlags flags)
  {
      BlockDriverState *bs = child->bs;
 -    BlockDriver *drv = bs->drv;
      BdrvTrackedRequest req;
 -
 -    uint64_t align = bs->bl.request_alignment;
 -    uint8_t *head_buf = NULL;
 -    uint8_t *tail_buf = NULL;
 -    QEMUIOVector local_qiov;
 -    bool use_local_qiov = false;
 +    BdrvRequestPadding pad;
      int ret;
 -    trace_bdrv_co_preadv(child->bs, offset, bytes, flags);
 -
 -    if (!drv) {
 -        return -ENOMEDIUM;
 -    }
 +    trace_bdrv_co_preadv(bs, offset, bytes, flags);
      ret = bdrv_check_byte_request(bs, offset, bytes);
      if (ret < 0) {
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child,
          flags |= BDRV_REQ_COPY_ON_READ;
      }
 -    /* Align read if necessary by padding qiov */
 -    if (offset & (align - 1)) {
 -        head_buf = qemu_blockalign(bs, align);
 -        qemu_iovec_init(&local_qiov, qiov->niov + 2);
 -        qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1));
 -        qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
 -        use_local_qiov = true;
 -
 -        bytes += offset & (align - 1);
 -        offset = offset & ~(align - 1);
 -    }
 -
--    if ((offset + bytes) & (align - 1)) {
+-    while (!QTAILQ_EMPTY(&server->vu_fd_watches)) {
--        if (!use_local_qiov) {
+-        QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
--            qemu_iovec_init(&local_qiov, qiov->niov + 1);
+-            if (!vu_fd_watch->processing) {
--            qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
+-                QTAILQ_REMOVE(&server->vu_fd_watches, vu_fd_watch, next);
--            use_local_qiov = true;
+-                g_free(vu_fd_watch);
--        }
+-            }
 -        tail_buf = qemu_blockalign(bs, align);
 -        qemu_iovec_add(&local_qiov, tail_buf,
 -                       align - ((offset + bytes) & (align - 1)));
 -
 -        bytes = ROUND_UP(bytes, align);
 -    }
 +    bdrv_pad_request(bs, &qiov, &offset, &bytes, &pad);
      tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_READ);
 -    ret = bdrv_aligned_preadv(child, &req, offset, bytes, align,
 -                              use_local_qiov ? &local_qiov : qiov,
 -                              flags);
 +    ret = bdrv_aligned_preadv(child, &req, offset, bytes,
 +                              bs->bl.request_alignment,
 +                              qiov, flags);
      tracked_request_end(&req);
      bdrv_dec_in_flight(bs);
 -    if (use_local_qiov) {
 -        qemu_iovec_destroy(&local_qiov);
 -        qemu_vfree(head_buf);
 -        qemu_vfree(tail_buf);
 -    }
 +    bdrv_padding_destroy(&pad);
      return ret;
  }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
                                                  BdrvTrackedRequest *req)
  {
      BlockDriverState *bs = child->bs;
 -    uint8_t *buf = NULL;
      QEMUIOVector local_qiov;
      uint64_t align = bs->bl.request_alignment;
 -    unsigned int head_padding_bytes, tail_padding_bytes;
      int ret = 0;
 +    bool padding;
 +    BdrvRequestPadding pad;
 -    head_padding_bytes = offset & (align - 1);
 -    tail_padding_bytes = (align - (offset + bytes)) & (align - 1);
 -
 -
 -    assert(flags & BDRV_REQ_ZERO_WRITE);
 -    if (head_padding_bytes || tail_padding_bytes) {
 -        buf = qemu_blockalign(bs, align);
 -        qemu_iovec_init_buf(&local_qiov, buf, align);
 -    }
 -    if (head_padding_bytes) {
 -        uint64_t zero_bytes = MIN(bytes, align - head_padding_bytes);
 -
 -        /* RMW the unaligned part before head. */
 +    padding = bdrv_init_padding(bs, offset, bytes, &pad);
 +    if (padding) {
          mark_request_serialising(req, align);
          wait_serialising_requests(req);
 -        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
 -        ret = bdrv_aligned_preadv(child, req, offset & ~(align - 1), align,
 -                                  align, &local_qiov, 0);
 -        if (ret < 0) {
 -            goto fail;
 -        }
 -        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
 -        memset(buf + head_padding_bytes, 0, zero_bytes);
 -        ret = bdrv_aligned_pwritev(child, req, offset & ~(align - 1), align,
 -                                   align, &local_qiov,
 -                                   flags & ~BDRV_REQ_ZERO_WRITE);
 -        if (ret < 0) {
 -            goto fail;
 +        bdrv_padding_rmw_read(child, req, &pad, true);
 +
 +        if (pad.head || pad.merge_reads) {
 +            int64_t aligned_offset = offset & ~(align - 1);
 +            int64_t write_bytes = pad.merge_reads ? pad.buf_len : align;
 +
 +            qemu_iovec_init_buf(&local_qiov, pad.buf, write_bytes);
 +            ret = bdrv_aligned_pwritev(child, req, aligned_offset, write_bytes,
 +                                       align, &local_qiov,
 +                                       flags & ~BDRV_REQ_ZERO_WRITE);
 +            if (ret < 0 || pad.merge_reads) {
 +                /* Error or all work is done */
 +                goto out;
 +            }
 +            offset += write_bytes - pad.head;
 +            bytes -= write_bytes - pad.head;
          }
 -        offset += zero_bytes;
 -        bytes -= zero_bytes;
      }
      assert(!bytes || (offset & (align - 1)) == 0);
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
          ret = bdrv_aligned_pwritev(child, req, offset, aligned_bytes, align,
                                     NULL, flags);
          if (ret < 0) {
 -            goto fail;
 +            goto out;
          }
          bytes -= aligned_bytes;
          offset += aligned_bytes;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
      assert(!bytes || (offset & (align - 1)) == 0);
      if (bytes) {
 -        assert(align == tail_padding_bytes + bytes);
 -        /* RMW the unaligned part after tail. */
 -        mark_request_serialising(req, align);
 -        wait_serialising_requests(req);
 -        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
 -        ret = bdrv_aligned_preadv(child, req, offset, align,
 -                                  align, &local_qiov, 0);
 -        if (ret < 0) {
 -            goto fail;
 -        }
 -        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
 +        assert(align == pad.tail + bytes);
 -        memset(buf, 0, bytes);
 +        qemu_iovec_init_buf(&local_qiov, pad.tail_buf, align);
          ret = bdrv_aligned_pwritev(child, req, offset, align, align,
                                     &local_qiov, flags & ~BDRV_REQ_ZERO_WRITE);
      }
 -fail:
 -    qemu_vfree(buf);
 +
 +out:
 +    bdrv_padding_destroy(&pad);
 +
      return ret;
 -
  }
  /*
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
      BlockDriverState *bs = child->bs;
      BdrvTrackedRequest req;
      uint64_t align = bs->bl.request_alignment;
 -    uint8_t *head_buf = NULL;
 -    uint8_t *tail_buf = NULL;
 -    QEMUIOVector local_qiov;
 -    bool use_local_qiov = false;
 +    BdrvRequestPadding pad;
      int ret;
      trace_bdrv_co_pwritev(child->bs, offset, bytes, flags);
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
          goto out;
      }
 -    if (offset & (align - 1)) {
 -        QEMUIOVector head_qiov;
 -
 +    if (bdrv_pad_request(bs, &qiov, &offset, &bytes, &pad)) {
          mark_request_serialising(&req, align);
          wait_serialising_requests(&req);
 -
 -        head_buf = qemu_blockalign(bs, align);
 -        qemu_iovec_init_buf(&head_qiov, head_buf, align);
 -
 -        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
 -        ret = bdrv_aligned_preadv(child, &req, offset & ~(align - 1), align,
 -                                  align, &head_qiov, 0);
 -        if (ret < 0) {
 -            goto fail;
 -        }
 -        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
 -
 -        qemu_iovec_init(&local_qiov, qiov->niov + 2);
 -        qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1));
 -        qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
 -        use_local_qiov = true;
 -
 -        bytes += offset & (align - 1);
 -        offset = offset & ~(align - 1);
 -
 -        /* We have read the tail already if the request is smaller
 -         * than one aligned block.
 -         */
 -        if (bytes < align) {
 -            qemu_iovec_add(&local_qiov, head_buf + bytes, align - bytes);
 -            bytes = align;
 -        }
 -    }
 -
--    if ((offset + bytes) & (align - 1)) {
+     while (server->processing_msg) {
--        QEMUIOVector tail_qiov;
+         if (server->ioc->read_coroutine) {
--        size_t tail_bytes;
+             server->ioc->read_coroutine = NULL;
--        bool waited;
+@@ -XXX,XX +XXX,XX @@ static void close_client(VuServer *server)
 -
 -        mark_request_serialising(&req, align);
 -        waited = wait_serialising_requests(&req);
 -        assert(!waited || !use_local_qiov);
 -
 -        tail_buf = qemu_blockalign(bs, align);
 -        qemu_iovec_init_buf(&tail_qiov, tail_buf, align);
 -
 -        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
 -        ret = bdrv_aligned_preadv(child, &req, (offset + bytes) & ~(align - 1),
 -                                  align, align, &tail_qiov, 0);
 -        if (ret < 0) {
 -            goto fail;
 -        }
 -        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
 -
 -        if (!use_local_qiov) {
 -            qemu_iovec_init(&local_qiov, qiov->niov + 1);
 -            qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
 -            use_local_qiov = true;
 -        }
 -
 -        tail_bytes = (offset + bytes) & (align - 1);
 -        qemu_iovec_add(&local_qiov, tail_buf + tail_bytes, align - tail_bytes);
 -
 -        bytes = ROUND_UP(bytes, align);
 +        bdrv_padding_rmw_read(child, &req, &pad, false);
      }
-     ret = bdrv_aligned_pwritev(child, &req, offset, bytes, align,
+     vu_deinit(&server->vu_dev);
 -                               use_local_qiov ? &local_qiov : qiov,
 -                               flags);
 +                               qiov, flags);
 -fail:
 +    bdrv_padding_destroy(&pad);
 -    if (use_local_qiov) {
 -        qemu_iovec_destroy(&local_qiov);
 -    }
 -    qemu_vfree(head_buf);
 -    qemu_vfree(tail_buf);
  out:
      tracked_request_end(&req);
      bdrv_dec_in_flight(bs);
 +
-     return ret;
++    /* vu_deinit() should have called remove_watch() */
 +    assert(QTAILQ_EMPTY(&server->vu_fd_watches));
 +
      object_unref(OBJECT(sioc));
      object_unref(OBJECT(server->ioc));
  }
 --
-.21.0
+.26.2

-[Qemu-devel] [PULL 02/12] util/iov: improve qemu_iovec_is_zero
+[PULL v2 11/28] block/export: consolidate request structs into VuBlockReq
-From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+Only one struct is needed per request. Drop req_data and the separate
 VuBlockReq instance. Instead let vu_queue_pop() allocate everything at
 once.
-We'll need to check a part of qiov soon, so implement it now.
+This fixes the req_data memory leak in vu_block_virtio_process_req().
-Optimization with align down to 4 * sizeof(long) is dropped due to:
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-. It is strange: it aligns length of the buffer, but where is a
+Message-id: 20200924151549.913737-6-stefanha@redhat.com
    guarantee that buffer pointer is aligned itself?
 . buffer_is_zero() is a better place for optimizations and it has
    them.
 Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
 Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
 Message-id: 20190604161514.262241-3-vsementsov@virtuozzo.com
 Message-Id: <20190604161514.262241-3-vsementsov@virtuozzo.com>
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- include/qemu/iov.h |  2 +-
+ block/export/vhost-user-blk-server.c | 68 +++++++++-------------------
- block/io.c         |  2 +-
+file changed, 21 insertions(+), 47 deletions(-)
  util/iov.c         | 31 +++++++++++++++++++------------
 files changed, 21 insertions(+), 14 deletions(-)
-diff --git a/include/qemu/iov.h b/include/qemu/iov.h
+diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
 index XXXXXXX..XXXXXXX 100644
---- a/include/qemu/iov.h
+--- a/block/export/vhost-user-blk-server.c
-+++ b/include/qemu/iov.h
++++ b/block/export/vhost-user-blk-server.c
-@@ -XXX,XX +XXX,XX @@ void qemu_iovec_concat(QEMUIOVector *dst,
+@@ -XXX,XX +XXX,XX @@ struct virtio_blk_inhdr {
- size_t qemu_iovec_concat_iov(QEMUIOVector *dst,
+ };
-                              struct iovec *src_iov, unsigned int src_cnt,
-                              size_t soffset, size_t sbytes);
+ typedef struct VuBlockReq {
--bool qemu_iovec_is_zero(QEMUIOVector *qiov);
+-    VuVirtqElement *elem;
-+bool qemu_iovec_is_zero(QEMUIOVector *qiov, size_t qiov_offeset, size_t bytes);
++    VuVirtqElement elem;
- void qemu_iovec_destroy(QEMUIOVector *qiov);
+     int64_t sector_num;
- void qemu_iovec_reset(QEMUIOVector *qiov);
+     size_t size;
- size_t qemu_iovec_to_buf(QEMUIOVector *qiov, size_t offset,
+     struct virtio_blk_inhdr *in;
-diff --git a/block/io.c b/block/io.c
+@@ -XXX,XX +XXX,XX @@ static void vu_block_req_complete(VuBlockReq *req)
-index XXXXXXX..XXXXXXX 100644
+     VuDev *vu_dev = &req->server->vu_dev;
---- a/block/io.c
-+++ b/block/io.c
+     /* IO size with 1 extra status byte */
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
+-    vu_queue_push(vu_dev, req->vq, req->elem, req->size + 1);
++    vu_queue_push(vu_dev, req->vq, &req->elem, req->size + 1);
-     if (!ret && bs->detect_zeroes != BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF &&
+     vu_queue_notify(vu_dev, req->vq);
-         !(flags & BDRV_REQ_ZERO_WRITE) && drv->bdrv_co_pwrite_zeroes &&
--        qemu_iovec_is_zero(qiov)) {
+-    if (req->elem) {
-+        qemu_iovec_is_zero(qiov, 0, qiov->size)) {
+-        free(req->elem);
-         flags |= BDRV_REQ_ZERO_WRITE;
+-    }
-         if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) {
+-
-             flags |= BDRV_REQ_MAY_UNMAP;
+-    g_free(req);
-diff --git a/util/iov.c b/util/iov.c
++    free(req);
 index XXXXXXX..XXXXXXX 100644
 --- a/util/iov.c
 +++ b/util/iov.c
@@ -XXX,XX +XXX,XX @@ void qemu_iovec_init_extended(
  }
- /*
+ static VuBlockDev *get_vu_block_device_by_server(VuServer *server)
-- * Check if the contents of the iovecs are all zero
+@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_flush(VuBlockReq *req)
-+ * Check if the contents of subrange of qiov data is all zeroes.
+     blk_co_flush(backend);
-  */
+ }
--bool qemu_iovec_is_zero(QEMUIOVector *qiov)
-+bool qemu_iovec_is_zero(QEMUIOVector *qiov, size_t offset, size_t bytes)
+-struct req_data {
 -    VuServer *server;
 -    VuVirtq *vq;
 -    VuVirtqElement *elem;
 -};
 -
  static void coroutine_fn vu_block_virtio_process_req(void *opaque)
  {
--    int i;
+-    struct req_data *data = opaque;
--    for (i = 0; i < qiov->niov; i++) {
+-    VuServer *server = data->server;
--        size_t offs = QEMU_ALIGN_DOWN(qiov->iov[i].iov_len, 4 * sizeof(long));
+-    VuVirtq *vq = data->vq;
--        uint8_t *ptr = qiov->iov[i].iov_base;
+-    VuVirtqElement *elem = data->elem;
--        if (offs && !buffer_is_zero(qiov->iov[i].iov_base, offs)) {
++    VuBlockReq *req = opaque;
-+    struct iovec *iov;
++    VuServer *server = req->server;
-+    size_t current_offset;
++    VuVirtqElement *elem = &req->elem;
      uint32_t type;
 -    VuBlockReq *req;
      VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
      BlockBackend *backend = vdev_blk->backend;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
      struct iovec *out_iov = elem->out_sg;
      unsigned in_num = elem->in_num;
      unsigned out_num = elem->out_num;
 +
-+    assert(offset + bytes <= qiov->size);
+     /* refer to hw/block/virtio_blk.c */
      if (elem->out_num < 1 || elem->in_num < 1) {
          error_report("virtio-blk request missing headers");
 -        free(elem);
 -        return;
 +        goto err;
      }
 -    req = g_new0(VuBlockReq, 1);
 -    req->server = server;
 -    req->vq = vq;
 -    req->elem = elem;
 -
      if (unlikely(iov_to_buf(out_iov, out_num, 0, &req->out,
                              sizeof(req->out)) != sizeof(req->out))) {
          error_report("virtio-blk request outhdr too short");
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
  err:
      free(elem);
 -    g_free(req);
 -    return;
  }
  static void vu_block_process_vq(VuDev *vu_dev, int idx)
  {
 -    VuServer *server;
 -    VuVirtq *vq;
 -    struct req_data *req_data;
 +    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
 +    VuVirtq *vq = vu_get_queue(vu_dev, idx);
 -    server = container_of(vu_dev, VuServer, vu_dev);
 -    assert(server);
 -
 -    vq = vu_get_queue(vu_dev, idx);
 -    assert(vq);
 -    VuVirtqElement *elem;
      while (1) {
 -        elem = vu_queue_pop(vu_dev, vq, sizeof(VuVirtqElement) +
 -                                    sizeof(VuBlockReq));
 -        if (elem) {
 -            req_data = g_new0(struct req_data, 1);
 -            req_data->server = server;
 -            req_data->vq = vq;
 -            req_data->elem = elem;
 -            Coroutine *co = qemu_coroutine_create(vu_block_virtio_process_req,
 -                                                  req_data);
 -            aio_co_enter(server->ioc->ctx, co);
 -        } else {
 +        VuBlockReq *req;
 +
-+    iov = iov_skip_offset(qiov->iov, offset, &current_offset);
++        req = vu_queue_pop(vu_dev, vq, sizeof(VuBlockReq));
 +        if (!req) {
              break;
          }
 +
-+    while (bytes) {
++        req->server = server;
-+        uint8_t *base = (uint8_t *)iov->iov_base + current_offset;
++        req->vq = vq;
 +        size_t len = MIN(iov->iov_len - current_offset, bytes);
 +
-+        if (!buffer_is_zero(base, len)) {
++        Coroutine *co =
-             return false;
++            qemu_coroutine_create(vu_block_virtio_process_req, req);
-         }
++        qemu_coroutine_enter(co);
 -        for (; offs < qiov->iov[i].iov_len; offs++) {
 -            if (ptr[offs]) {
 -                return false;
 -            }
 -        }
 +
 +        current_offset = 0;
 +        bytes -= len;
 +        iov++;
      }
-+
-     return true;
  }
 --
-.21.0
+.26.2

-New patch
+[PULL v2 12/28] util/vhost-user-server: drop unused DevicePanicNotifier
+The device panic notifier callback is not used. Drop it.
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200924151549.913737-7-stefanha@redhat.com
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ util/vhost-user-server.h             | 3 ---
+ block/export/vhost-user-blk-server.c | 3 +--
+ util/vhost-user-server.c             | 6 ------
+files changed, 1 insertion(+), 11 deletions(-)
+diff --git a/util/vhost-user-server.h b/util/vhost-user-server.h
+index XXXXXXX..XXXXXXX 100644
+--- a/util/vhost-user-server.h
++++ b/util/vhost-user-server.h
+@@ -XXX,XX +XXX,XX @@ typedef struct VuFdWatch {
+ } VuFdWatch;
+ typedef struct VuServer VuServer;
+-typedef void DevicePanicNotifierFn(VuServer *server);
+ struct VuServer {
+     QIONetListener *listener;
+     AioContext *ctx;
+-    DevicePanicNotifierFn *device_panic_notifier;
+     int max_queues;
+     const VuDevIface *vu_iface;
+     VuDev vu_dev;
+@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
+                              SocketAddress *unix_socket,
+                              AioContext *ctx,
+                              uint16_t max_queues,
+-                             DevicePanicNotifierFn *device_panic_notifier,
+                              const VuDevIface *vu_iface,
+                              Error **errp);
+diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/block/export/vhost-user-blk-server.c
++++ b/block/export/vhost-user-blk-server.c
+@@ -XXX,XX +XXX,XX @@ static void vhost_user_blk_server_start(VuBlockDev *vu_block_device,
+     ctx = bdrv_get_aio_context(blk_bs(vu_block_device->backend));
+     if (!vhost_user_server_start(&vu_block_device->vu_server, addr, ctx,
+-                                 VHOST_USER_BLK_MAX_QUEUES,
+-                                 NULL, &vu_block_iface,
++                                 VHOST_USER_BLK_MAX_QUEUES, &vu_block_iface,
+                                  errp)) {
+         goto error;
+     }
+diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/util/vhost-user-server.c
++++ b/util/vhost-user-server.c
+@@ -XXX,XX +XXX,XX @@ static void panic_cb(VuDev *vu_dev, const char *buf)
+         close_client(server);
+     }
+-    if (server->device_panic_notifier) {
+-        server->device_panic_notifier(server);
+-    }
+-
+     /*
+      * Set the callback function for network listener so another
+      * vhost-user client can connect to this server
+@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
+                              SocketAddress *socket_addr,
+                              AioContext *ctx,
+                              uint16_t max_queues,
+-                             DevicePanicNotifierFn *device_panic_notifier,
+                              const VuDevIface *vu_iface,
+                              Error **errp)
+ {
+@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
+         .vu_iface              = vu_iface,
+         .max_queues            = max_queues,
+         .ctx                   = ctx,
+-        .device_panic_notifier = device_panic_notifier,
+     };
+     qio_net_listener_set_name(server->listener, "vhost-user-backend-listener");
+--
+.26.2

-New patch
+[PULL v2 13/28] util/vhost-user-server: fix memory leak in vu_message_read()
+fds[] is leaked when qio_channel_readv_full() fails.
+Use vmsg->fds[] instead of keeping a local fds[] array. Then we can
+reuse goto fail to clean up fds. vmsg->fd_num must be zeroed before the
+loop to make this safe.
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200924151549.913737-8-stefanha@redhat.com
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ util/vhost-user-server.c | 50 ++++++++++++++++++----------------------
+file changed, 23 insertions(+), 27 deletions(-)
+diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/util/vhost-user-server.c
++++ b/util/vhost-user-server.c
+@@ -XXX,XX +XXX,XX @@ vu_message_read(VuDev *vu_dev, int conn_fd, VhostUserMsg *vmsg)
+     };
+     int rc, read_bytes = 0;
+     Error *local_err = NULL;
+-    /*
+-     * Store fds/nfds returned from qio_channel_readv_full into
+-     * temporary variables.
+-     *
+-     * VhostUserMsg is a packed structure, gcc will complain about passing
+-     * pointer to a packed structure member if we pass &VhostUserMsg.fd_num
+-     * and &VhostUserMsg.fds directly when calling qio_channel_readv_full,
+-     * thus two temporary variables nfds and fds are used here.
+-     */
+-    size_t nfds = 0, nfds_t = 0;
+     const size_t max_fds = G_N_ELEMENTS(vmsg->fds);
+-    int *fds_t = NULL;
+     VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+     QIOChannel *ioc = server->ioc;
++    vmsg->fd_num = 0;
+     if (!ioc) {
+         error_report_err(local_err);
+         goto fail;
+@@ -XXX,XX +XXX,XX @@ vu_message_read(VuDev *vu_dev, int conn_fd, VhostUserMsg *vmsg)
+     assert(qemu_in_coroutine());
+     do {
++        size_t nfds = 0;
++        int *fds = NULL;
++
+         /*
+          * qio_channel_readv_full may have short reads, keeping calling it
+          * until getting VHOST_USER_HDR_SIZE or 0 bytes in total
+          */
+-        rc = qio_channel_readv_full(ioc, &iov, 1, &fds_t, &nfds_t, &local_err);
++        rc = qio_channel_readv_full(ioc, &iov, 1, &fds, &nfds, &local_err);
+         if (rc < 0) {
+             if (rc == QIO_CHANNEL_ERR_BLOCK) {
++                assert(local_err == NULL);
+                 qio_channel_yield(ioc, G_IO_IN);
+                 continue;
+             } else {
+                 error_report_err(local_err);
+-                return false;
++                goto fail;
+             }
+         }
+-        read_bytes += rc;
+-        if (nfds_t > 0) {
+-            if (nfds + nfds_t > max_fds) {
++
++        if (nfds > 0) {
++            if (vmsg->fd_num + nfds > max_fds) {
+                 error_report("A maximum of %zu fds are allowed, "
+                              "however got %zu fds now",
+-                             max_fds, nfds + nfds_t);
++                             max_fds, vmsg->fd_num + nfds);
++                g_free(fds);
+                 goto fail;
+             }
+-            memcpy(vmsg->fds + nfds, fds_t,
+-                   nfds_t *sizeof(vmsg->fds[0]));
+-            nfds += nfds_t;
+-            g_free(fds_t);
++            memcpy(vmsg->fds + vmsg->fd_num, fds, nfds * sizeof(vmsg->fds[0]));
++            vmsg->fd_num += nfds;
++            g_free(fds);
+         }
+-        if (read_bytes == VHOST_USER_HDR_SIZE || rc == 0) {
+-            break;
++
++        if (rc == 0) { /* socket closed */
++            goto fail;
+         }
+-        iov.iov_base = (char *)vmsg + read_bytes;
+-        iov.iov_len = VHOST_USER_HDR_SIZE - read_bytes;
+-    } while (true);
+-    vmsg->fd_num = nfds;
++        iov.iov_base += rc;
++        iov.iov_len -= rc;
++        read_bytes += rc;
++    } while (read_bytes != VHOST_USER_HDR_SIZE);
++
+     /* qio_channel_readv_full will make socket fds blocking, unblock them */
+     vmsg_unblock_fds(vmsg);
+     if (vmsg->size > sizeof(vmsg->payload)) {
+--
+.26.2

-New patch
+[PULL v2 14/28] util/vhost-user-server: check EOF when reading payload
+Unexpected EOF is an error that must be reported.
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200924151549.913737-9-stefanha@redhat.com
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ util/vhost-user-server.c | 6 ++++--
+file changed, 4 insertions(+), 2 deletions(-)
+diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/util/vhost-user-server.c
++++ b/util/vhost-user-server.c
+@@ -XXX,XX +XXX,XX @@ vu_message_read(VuDev *vu_dev, int conn_fd, VhostUserMsg *vmsg)
+     };
+     if (vmsg->size) {
+         rc = qio_channel_readv_all_eof(ioc, &iov_payload, 1, &local_err);
+-        if (rc == -1) {
+-            error_report_err(local_err);
++        if (rc != 1) {
++            if (local_err) {
++                error_report_err(local_err);
++            }
+             goto fail;
+         }
+     }
+--
+.26.2

-New patch
+[PULL v2 15/28] util/vhost-user-server: rework vu_client_trip() coroutine lifecycle
+The vu_client_trip() coroutine is leaked during AioContext switching. It
+is also unsafe to destroy the vu_dev in panic_cb() since its callers
+still access it in some cases.
+Rework the lifecycle to solve these safety issues.
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200924151549.913737-10-stefanha@redhat.com
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ util/vhost-user-server.h             |  29 ++--
+ block/export/vhost-user-blk-server.c |   9 +-
+ util/vhost-user-server.c             | 245 +++++++++++++++------------
+files changed, 155 insertions(+), 128 deletions(-)
+diff --git a/util/vhost-user-server.h b/util/vhost-user-server.h
+index XXXXXXX..XXXXXXX 100644
+--- a/util/vhost-user-server.h
++++ b/util/vhost-user-server.h
+@@ -XXX,XX +XXX,XX @@
+ #include "qapi/error.h"
+ #include "standard-headers/linux/virtio_blk.h"
++/* A kick fd that we monitor on behalf of libvhost-user */
+ typedef struct VuFdWatch {
+     VuDev *vu_dev;
+     int fd; /*kick fd*/
+     void *pvt;
+     vu_watch_cb cb;
+-    bool processing;
+     QTAILQ_ENTRY(VuFdWatch) next;
+ } VuFdWatch;
+-typedef struct VuServer VuServer;
+-
+-struct VuServer {
++/**
++ * VuServer:
++ * A vhost-user server instance with user-defined VuDevIface callbacks.
++ * Vhost-user device backends can be implemented using VuServer. VuDevIface
++ * callbacks and virtqueue kicks run in the given AioContext.
++ */
++typedef struct {
+     QIONetListener *listener;
++    QEMUBH *restart_listener_bh;
+     AioContext *ctx;
+     int max_queues;
+     const VuDevIface *vu_iface;
++
++    /* Protected by ctx lock */
+     VuDev vu_dev;
+     QIOChannel *ioc; /* The I/O channel with the client */
+     QIOChannelSocket *sioc; /* The underlying data channel with the client */
+-    /* IOChannel for fd provided via VHOST_USER_SET_SLAVE_REQ_FD */
+-    QIOChannel *ioc_slave;
+-    QIOChannelSocket *sioc_slave;
+-    Coroutine *co_trip; /* coroutine for processing VhostUserMsg */
+     QTAILQ_HEAD(, VuFdWatch) vu_fd_watches;
+-    /* restart coroutine co_trip if AIOContext is changed */
+-    bool aio_context_changed;
+-    bool processing_msg;
+-};
++
++    Coroutine *co_trip; /* coroutine for processing VhostUserMsg */
++} VuServer;
+ bool vhost_user_server_start(VuServer *server,
+                              SocketAddress *unix_socket,
+@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
+ void vhost_user_server_stop(VuServer *server);
+-void vhost_user_server_set_aio_context(VuServer *server, AioContext *ctx);
++void vhost_user_server_attach_aio_context(VuServer *server, AioContext *ctx);
++void vhost_user_server_detach_aio_context(VuServer *server);
+ #endif /* VHOST_USER_SERVER_H */
+diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/block/export/vhost-user-blk-server.c
++++ b/block/export/vhost-user-blk-server.c
+@@ -XXX,XX +XXX,XX @@ static const VuDevIface vu_block_iface = {
+ static void blk_aio_attached(AioContext *ctx, void *opaque)
+ {
+     VuBlockDev *vub_dev = opaque;
+-    aio_context_acquire(ctx);
+-    vhost_user_server_set_aio_context(&vub_dev->vu_server, ctx);
+-    aio_context_release(ctx);
++    vhost_user_server_attach_aio_context(&vub_dev->vu_server, ctx);
+ }
+ static void blk_aio_detach(void *opaque)
+ {
+     VuBlockDev *vub_dev = opaque;
+-    AioContext *ctx = vub_dev->vu_server.ctx;
+-    aio_context_acquire(ctx);
+-    vhost_user_server_set_aio_context(&vub_dev->vu_server, NULL);
+-    aio_context_release(ctx);
++    vhost_user_server_detach_aio_context(&vub_dev->vu_server);
+ }
+ static void
+diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/util/vhost-user-server.c
++++ b/util/vhost-user-server.c
+@@ -XXX,XX +XXX,XX @@
+  */
+ #include "qemu/osdep.h"
+ #include "qemu/main-loop.h"
++#include "block/aio-wait.h"
+ #include "vhost-user-server.h"
++/*
++ * Theory of operation:
++ *
++ * VuServer is started and stopped by vhost_user_server_start() and
++ * vhost_user_server_stop() from the main loop thread. Starting the server
++ * opens a vhost-user UNIX domain socket and listens for incoming connections.
++ * Only one connection is allowed at a time.
++ *
++ * The connection is handled by the vu_client_trip() coroutine in the
++ * VuServer->ctx AioContext. The coroutine consists of a vu_dispatch() loop
++ * where libvhost-user calls vu_message_read() to receive the next vhost-user
++ * protocol messages over the UNIX domain socket.
++ *
++ * When virtqueues are set up libvhost-user calls set_watch() to monitor kick
++ * fds. These fds are also handled in the VuServer->ctx AioContext.
++ *
++ * Both vu_client_trip() and kick fd monitoring can be stopped by shutting down
++ * the socket connection. Shutting down the socket connection causes
++ * vu_message_read() to fail since no more data can be received from the socket.
++ * After vu_dispatch() fails, vu_client_trip() calls vu_deinit() to stop
++ * libvhost-user before terminating the coroutine. vu_deinit() calls
++ * remove_watch() to stop monitoring kick fds and this stops virtqueue
++ * processing.
++ *
++ * When vu_client_trip() has finished cleaning up it schedules a BH in the main
++ * loop thread to accept the next client connection.
++ *
++ * When libvhost-user detects an error it calls panic_cb() and sets the
++ * dev->broken flag. Both vu_client_trip() and kick fd processing stop when
++ * the dev->broken flag is set.
++ *
++ * It is possible to switch AioContexts using
++ * vhost_user_server_detach_aio_context() and
++ * vhost_user_server_attach_aio_context(). They stop monitoring fds in the old
++ * AioContext and resume monitoring in the new AioContext. The vu_client_trip()
++ * coroutine remains in a yielded state during the switch. This is made
++ * possible by QIOChannel's support for spurious coroutine re-entry in
++ * qio_channel_yield(). The coroutine will restart I/O when re-entered from the
++ * new AioContext.
++ */
++
+ static void vmsg_close_fds(VhostUserMsg *vmsg)
+ {
+     int i;
+@@ -XXX,XX +XXX,XX @@ static void vmsg_unblock_fds(VhostUserMsg *vmsg)
+     }
+ }
+-static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
+-                      gpointer opaque);
+-
+-static void close_client(VuServer *server)
+-{
+-    /*
+-     * Before closing the client
+-     *
+-     * 1. Let vu_client_trip stop processing new vhost-user msg
+-     *
+-     * 2. remove kick_handler
+-     *
+-     * 3. wait for the kick handler to be finished
+-     *
+-     * 4. wait for the current vhost-user msg to be finished processing
+-     */
+-
+-    QIOChannelSocket *sioc = server->sioc;
+-    /* When this is set vu_client_trip will stop new processing vhost-user message */
+-    server->sioc = NULL;
+-
+-    while (server->processing_msg) {
+-        if (server->ioc->read_coroutine) {
+-            server->ioc->read_coroutine = NULL;
+-            qio_channel_set_aio_fd_handler(server->ioc, server->ioc->ctx, NULL,
+-                                           NULL, server->ioc);
+-            server->processing_msg = false;
+-        }
+-    }
+-
+-    vu_deinit(&server->vu_dev);
+-
+-    /* vu_deinit() should have called remove_watch() */
+-    assert(QTAILQ_EMPTY(&server->vu_fd_watches));
+-
+-    object_unref(OBJECT(sioc));
+-    object_unref(OBJECT(server->ioc));
+-}
+-
+ static void panic_cb(VuDev *vu_dev, const char *buf)
+ {
+-    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+-
+-    /* avoid while loop in close_client */
+-    server->processing_msg = false;
+-
+-    if (buf) {
+-        error_report("vu_panic: %s", buf);
+-    }
+-
+-    if (server->sioc) {
+-        close_client(server);
+-    }
+-
+-    /*
+-     * Set the callback function for network listener so another
+-     * vhost-user client can connect to this server
+-     */
+-    qio_net_listener_set_client_func(server->listener,
+-                                     vu_accept,
+-                                     server,
+-                                     NULL);
++    error_report("vu_panic: %s", buf);
+ }
+ static bool coroutine_fn
+@@ -XXX,XX +XXX,XX @@ fail:
+     return false;
+ }
+-
+-static void vu_client_start(VuServer *server);
+ static coroutine_fn void vu_client_trip(void *opaque)
+ {
+     VuServer *server = opaque;
++    VuDev *vu_dev = &server->vu_dev;
+-    while (!server->aio_context_changed && server->sioc) {
+-        server->processing_msg = true;
+-        vu_dispatch(&server->vu_dev);
+-        server->processing_msg = false;
++    while (!vu_dev->broken && vu_dispatch(vu_dev)) {
++        /* Keep running */
+     }
+-    if (server->aio_context_changed && server->sioc) {
+-        server->aio_context_changed = false;
+-        vu_client_start(server);
+-    }
+-}
++    vu_deinit(vu_dev);
++
++    /* vu_deinit() should have called remove_watch() */
++    assert(QTAILQ_EMPTY(&server->vu_fd_watches));
++
++    object_unref(OBJECT(server->sioc));
++    server->sioc = NULL;
+-static void vu_client_start(VuServer *server)
+-{
+-    server->co_trip = qemu_coroutine_create(vu_client_trip, server);
+-    aio_co_enter(server->ctx, server->co_trip);
++    object_unref(OBJECT(server->ioc));
++    server->ioc = NULL;
++
++    server->co_trip = NULL;
++    if (server->restart_listener_bh) {
++        qemu_bh_schedule(server->restart_listener_bh);
++    }
++    aio_wait_kick();
+ }
+ /*
+@@ -XXX,XX +XXX,XX @@ static void vu_client_start(VuServer *server)
+ static void kick_handler(void *opaque)
+ {
+     VuFdWatch *vu_fd_watch = opaque;
+-    vu_fd_watch->processing = true;
+-    vu_fd_watch->cb(vu_fd_watch->vu_dev, 0, vu_fd_watch->pvt);
+-    vu_fd_watch->processing = false;
++    VuDev *vu_dev = vu_fd_watch->vu_dev;
++
++    vu_fd_watch->cb(vu_dev, 0, vu_fd_watch->pvt);
++
++    /* Stop vu_client_trip() if an error occurred in vu_fd_watch->cb() */
++    if (vu_dev->broken) {
++        VuServer *server = container_of(vu_dev, VuServer, vu_dev);
++
++        qio_channel_shutdown(server->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
++    }
+ }
+-
+ static VuFdWatch *find_vu_fd_watch(VuServer *server, int fd)
+ {
+@@ -XXX,XX +XXX,XX @@ static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
+     qio_channel_set_name(QIO_CHANNEL(sioc), "vhost-user client");
+     server->ioc = QIO_CHANNEL(sioc);
+     object_ref(OBJECT(server->ioc));
+-    qio_channel_attach_aio_context(server->ioc, server->ctx);
++
++    /* TODO vu_message_write() spins if non-blocking! */
+     qio_channel_set_blocking(server->ioc, false, NULL);
+-    vu_client_start(server);
++
++    server->co_trip = qemu_coroutine_create(vu_client_trip, server);
++
++    aio_context_acquire(server->ctx);
++    vhost_user_server_attach_aio_context(server, server->ctx);
++    aio_context_release(server->ctx);
+ }
+-
+ void vhost_user_server_stop(VuServer *server)
+ {
++    aio_context_acquire(server->ctx);
++
++    qemu_bh_delete(server->restart_listener_bh);
++    server->restart_listener_bh = NULL;
++
+     if (server->sioc) {
+-        close_client(server);
++        VuFdWatch *vu_fd_watch;
++
++        QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
++            aio_set_fd_handler(server->ctx, vu_fd_watch->fd, true,
++                               NULL, NULL, NULL, vu_fd_watch);
++        }
++
++        qio_channel_shutdown(server->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
++
++        AIO_WAIT_WHILE(server->ctx, server->co_trip);
+     }
++    aio_context_release(server->ctx);
++
+     if (server->listener) {
+         qio_net_listener_disconnect(server->listener);
+         object_unref(OBJECT(server->listener));
+     }
++}
++
++/*
++ * Allow the next client to connect to the server. Called from a BH in the main
++ * loop.
++ */
++static void restart_listener_bh(void *opaque)
++{
++    VuServer *server = opaque;
++    qio_net_listener_set_client_func(server->listener, vu_accept, server,
++                                     NULL);
+ }
+-void vhost_user_server_set_aio_context(VuServer *server, AioContext *ctx)
++/* Called with ctx acquired */
++void vhost_user_server_attach_aio_context(VuServer *server, AioContext *ctx)
+ {
+-    VuFdWatch *vu_fd_watch, *next;
+-    void *opaque = NULL;
+-    IOHandler *io_read = NULL;
+-    bool attach;
++    VuFdWatch *vu_fd_watch;
+-    server->ctx = ctx ? ctx : qemu_get_aio_context();
++    server->ctx = ctx;
+     if (!server->sioc) {
+-        /* not yet serving any client*/
+         return;
+     }
+-    if (ctx) {
+-        qio_channel_attach_aio_context(server->ioc, ctx);
+-        server->aio_context_changed = true;
+-        io_read = kick_handler;
+-        attach = true;
+-    } else {
++    qio_channel_attach_aio_context(server->ioc, ctx);
++
++    QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
++        aio_set_fd_handler(ctx, vu_fd_watch->fd, true, kick_handler, NULL,
++                           NULL, vu_fd_watch);
++    }
++
++    aio_co_schedule(ctx, server->co_trip);
++}
++
++/* Called with server->ctx acquired */
++void vhost_user_server_detach_aio_context(VuServer *server)
++{
++    if (server->sioc) {
++        VuFdWatch *vu_fd_watch;
++
++        QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
++            aio_set_fd_handler(server->ctx, vu_fd_watch->fd, true,
++                               NULL, NULL, NULL, vu_fd_watch);
++        }
++
+         qio_channel_detach_aio_context(server->ioc);
+-        /* server->ioc->ctx keeps the old AioConext */
+-        ctx = server->ioc->ctx;
+-        attach = false;
+     }
+-    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
+-        if (vu_fd_watch->cb) {
+-            opaque = attach ? vu_fd_watch : NULL;
+-            aio_set_fd_handler(ctx, vu_fd_watch->fd, true,
+-                               io_read, NULL, NULL,
+-                               opaque);
+-        }
+-    }
++    server->ctx = NULL;
+ }
+-
+ bool vhost_user_server_start(VuServer *server,
+                              SocketAddress *socket_addr,
+                              AioContext *ctx,
+@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
+                              const VuDevIface *vu_iface,
+                              Error **errp)
+ {
++    QEMUBH *bh;
+     QIONetListener *listener = qio_net_listener_new();
+     if (qio_net_listener_open_sync(listener, socket_addr, 1,
+                                    errp) < 0) {
+@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
+         return false;
+     }
++    bh = qemu_bh_new(restart_listener_bh, server);
++
+     /* zero out unspecified fields */
+     *server = (VuServer) {
+         .listener              = listener,
++        .restart_listener_bh   = bh,
+         .vu_iface              = vu_iface,
+         .max_queues            = max_queues,
+         .ctx                   = ctx,
+--
+.26.2

-New patch
+[PULL v2 16/28] block/export: report flush errors
+Propagate the flush return value since errors are possible.
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200924151549.913737-11-stefanha@redhat.com
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ block/export/vhost-user-blk-server.c | 11 +++++++----
+file changed, 7 insertions(+), 4 deletions(-)
+diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/block/export/vhost-user-blk-server.c
++++ b/block/export/vhost-user-blk-server.c
+@@ -XXX,XX +XXX,XX @@ vu_block_discard_write_zeroes(VuBlockReq *req, struct iovec *iov,
+     return -EINVAL;
+ }
+-static void coroutine_fn vu_block_flush(VuBlockReq *req)
++static int coroutine_fn vu_block_flush(VuBlockReq *req)
+ {
+     VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server);
+     BlockBackend *backend = vdev_blk->backend;
+-    blk_co_flush(backend);
++    return blk_co_flush(backend);
+ }
+ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
+@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
+         break;
+     }
+     case VIRTIO_BLK_T_FLUSH:
+-        vu_block_flush(req);
+-        req->in->status = VIRTIO_BLK_S_OK;
++        if (vu_block_flush(req) == 0) {
++            req->in->status = VIRTIO_BLK_S_OK;
++        } else {
++            req->in->status = VIRTIO_BLK_S_IOERR;
++        }
+         break;
+     case VIRTIO_BLK_T_GET_ID: {
+         size_t size = MIN(iov_size(&elem->in_sg[0], in_num),
+--
+.26.2

-New patch
+[PULL v2 17/28] block/export: convert vhost-user-blk server to block export API
+Use the new QAPI block exports API instead of defining our own QOM
 objects.
 This is a large change because the lifecycle of VuBlockDev needs to
 follow BlockExportDriver. QOM properties are replaced by QAPI options
 objects.
 VuBlockDev is renamed VuBlkExport and contains a BlockExport field.
 Several fields can be dropped since BlockExport already has equivalents.
 The file names and meson build integration will be adjusted in a future
 patch. libvhost-user should probably be built as a static library that
 is linked into QEMU instead of as a .c file that results in duplicate
 compilation.
 The new command-line syntax is:
   $ qemu-storage-daemon \
       --blockdev file,node-name=drive0,filename=test.img \
       --export vhost-user-blk,node-name=drive0,id=export0,unix-socket=/tmp/vhost-user-blk.sock
 Note that unix-socket is optional because we may wish to accept chardevs
 too in the future.
 Markus noted that supported address families are not explicit in the
 QAPI schema. It is unlikely that support for more address families will
 be added since file descriptor passing is required and few address
 families support it. If a new address family needs to be added, then the
 QAPI 'features' syntax can be used to advertize them.
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 Acked-by: Markus Armbruster <armbru@redhat.com>
 Message-id: 20200924151549.913737-12-stefanha@redhat.com
 [Skip test on big-endian host architectures because this device doesn't
 support them yet (as already mentioned in a code comment).
 --Stefan]
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
  qapi/block-export.json               |  21 +-
  block/export/vhost-user-blk-server.h |  23 +-
  block/export/export.c                |   6 +
  block/export/vhost-user-blk-server.c | 452 +++++++--------------------
  util/vhost-user-server.c             |  10 +-
  block/export/meson.build             |   1 +
  block/meson.build                    |   1 -
 files changed, 156 insertions(+), 358 deletions(-)
 diff --git a/qapi/block-export.json b/qapi/block-export.json
 index XXXXXXX..XXXXXXX 100644
 --- a/qapi/block-export.json
 +++ b/qapi/block-export.json
@@ -XXX,XX +XXX,XX @@
    'data': { '*name': 'str', '*description': 'str',
              '*bitmap': 'str' } }
 +##
 +# @BlockExportOptionsVhostUserBlk:
 +#
 +# A vhost-user-blk block export.
 +#
 +# @addr: The vhost-user socket on which to listen. Both 'unix' and 'fd'
 +#        SocketAddress types are supported. Passed fds must be UNIX domain
 +#        sockets.
 +# @logical-block-size: Logical block size in bytes. Defaults to 512 bytes.
 +#
 +# Since: 5.2
 +##
 +{ 'struct': 'BlockExportOptionsVhostUserBlk',
 +  'data': { 'addr': 'SocketAddress', '*logical-block-size': 'size' } }
 +
  ##
  # @NbdServerAddOptions:
  #
@@ -XXX,XX +XXX,XX @@
  # An enumeration of block export types
  #
  # @nbd: NBD export
 +# @vhost-user-blk: vhost-user-blk export (since 5.2)
  #
  # Since: 4.2
  ##
  { 'enum': 'BlockExportType',
 -  'data': [ 'nbd' ] }
 +  'data': [ 'nbd', 'vhost-user-blk' ] }
  ##
  # @BlockExportOptions:
@@ -XXX,XX +XXX,XX @@
              '*writethrough': 'bool' },
    'discriminator': 'type',
    'data': {
 -      'nbd': 'BlockExportOptionsNbd'
 +      'nbd': 'BlockExportOptionsNbd',
 +      'vhost-user-blk': 'BlockExportOptionsVhostUserBlk'
     } }
  ##
 diff --git a/block/export/vhost-user-blk-server.h b/block/export/vhost-user-blk-server.h
 index XXXXXXX..XXXXXXX 100644
 --- a/block/export/vhost-user-blk-server.h
 +++ b/block/export/vhost-user-blk-server.h
@@ -XXX,XX +XXX,XX @@
  #ifndef VHOST_USER_BLK_SERVER_H
  #define VHOST_USER_BLK_SERVER_H
 -#include "util/vhost-user-server.h"
 -typedef struct VuBlockDev VuBlockDev;
 -#define TYPE_VHOST_USER_BLK_SERVER "vhost-user-blk-server"
 -#define VHOST_USER_BLK_SERVER(obj) \
 -   OBJECT_CHECK(VuBlockDev, obj, TYPE_VHOST_USER_BLK_SERVER)
 +#include "block/export.h"
 -/* vhost user block device */
 -struct VuBlockDev {
 -    Object parent_obj;
 -    char *node_name;
 -    SocketAddress *addr;
 -    AioContext *ctx;
 -    VuServer vu_server;
 -    bool running;
 -    uint32_t blk_size;
 -    BlockBackend *backend;
 -    QIOChannelSocket *sioc;
 -    QTAILQ_ENTRY(VuBlockDev) next;
 -    struct virtio_blk_config blkcfg;
 -    bool writable;
 -};
 +/* For block/export/export.c */
 +extern const BlockExportDriver blk_exp_vhost_user_blk;
  #endif /* VHOST_USER_BLK_SERVER_H */
 diff --git a/block/export/export.c b/block/export/export.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/export/export.c
 +++ b/block/export/export.c
@@ -XXX,XX +XXX,XX @@
  #include "sysemu/block-backend.h"
  #include "block/export.h"
  #include "block/nbd.h"
 +#if CONFIG_LINUX
 +#include "block/export/vhost-user-blk-server.h"
 +#endif
  #include "qapi/error.h"
  #include "qapi/qapi-commands-block-export.h"
  #include "qapi/qapi-events-block-export.h"
@@ -XXX,XX +XXX,XX @@
  static const BlockExportDriver *blk_exp_drivers[] = {
      &blk_exp_nbd,
 +#if CONFIG_LINUX
 +    &blk_exp_vhost_user_blk,
 +#endif
  };
  /* Only accessed from the main thread */
 diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/export/vhost-user-blk-server.c
 +++ b/block/export/vhost-user-blk-server.c
@@ -XXX,XX +XXX,XX @@
   */
  #include "qemu/osdep.h"
  #include "block/block.h"
 +#include "contrib/libvhost-user/libvhost-user.h"
 +#include "standard-headers/linux/virtio_blk.h"
 +#include "util/vhost-user-server.h"
  #include "vhost-user-blk-server.h"
  #include "qapi/error.h"
  #include "qom/object_interfaces.h"
@@ -XXX,XX +XXX,XX @@ struct virtio_blk_inhdr {
      unsigned char status;
  };
 -typedef struct VuBlockReq {
 +typedef struct VuBlkReq {
      VuVirtqElement elem;
      int64_t sector_num;
      size_t size;
@@ -XXX,XX +XXX,XX @@ typedef struct VuBlockReq {
      struct virtio_blk_outhdr out;
      VuServer *server;
      struct VuVirtq *vq;
 -} VuBlockReq;
 +} VuBlkReq;
 -static void vu_block_req_complete(VuBlockReq *req)
 +/* vhost user block device */
 +typedef struct {
 +    BlockExport export;
 +    VuServer vu_server;
 +    uint32_t blk_size;
 +    QIOChannelSocket *sioc;
 +    struct virtio_blk_config blkcfg;
 +    bool writable;
 +} VuBlkExport;
 +
 +static void vu_blk_req_complete(VuBlkReq *req)
  {
      VuDev *vu_dev = &req->server->vu_dev;
@@ -XXX,XX +XXX,XX @@ static void vu_block_req_complete(VuBlockReq *req)
      free(req);
  }
 -static VuBlockDev *get_vu_block_device_by_server(VuServer *server)
 -{
 -    return container_of(server, VuBlockDev, vu_server);
 -}
 -
  static int coroutine_fn
 -vu_block_discard_write_zeroes(VuBlockReq *req, struct iovec *iov,
 -                              uint32_t iovcnt, uint32_t type)
 +vu_blk_discard_write_zeroes(BlockBackend *blk, struct iovec *iov,
 +                            uint32_t iovcnt, uint32_t type)
  {
      struct virtio_blk_discard_write_zeroes desc;
      ssize_t size = iov_to_buf(iov, iovcnt, 0, &desc, sizeof(desc));
@@ -XXX,XX +XXX,XX @@ vu_block_discard_write_zeroes(VuBlockReq *req, struct iovec *iov,
          return -EINVAL;
      }
 -    VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server);
      uint64_t range[2] = { le64_to_cpu(desc.sector) << 9,
                            le32_to_cpu(desc.num_sectors) << 9 };
      if (type == VIRTIO_BLK_T_DISCARD) {
 -        if (blk_co_pdiscard(vdev_blk->backend, range[0], range[1]) == 0) {
 +        if (blk_co_pdiscard(blk, range[0], range[1]) == 0) {
              return 0;
          }
      } else if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
 -        if (blk_co_pwrite_zeroes(vdev_blk->backend,
 -                                 range[0], range[1], 0) == 0) {
 +        if (blk_co_pwrite_zeroes(blk, range[0], range[1], 0) == 0) {
              return 0;
          }
      }
@@ -XXX,XX +XXX,XX @@ vu_block_discard_write_zeroes(VuBlockReq *req, struct iovec *iov,
      return -EINVAL;
  }
 -static int coroutine_fn vu_block_flush(VuBlockReq *req)
 +static void coroutine_fn vu_blk_virtio_process_req(void *opaque)
  {
 -    VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server);
 -    BlockBackend *backend = vdev_blk->backend;
 -    return blk_co_flush(backend);
 -}
 -
 -static void coroutine_fn vu_block_virtio_process_req(void *opaque)
 -{
 -    VuBlockReq *req = opaque;
 +    VuBlkReq *req = opaque;
      VuServer *server = req->server;
      VuVirtqElement *elem = &req->elem;
      uint32_t type;
 -    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
 -    BlockBackend *backend = vdev_blk->backend;
 +    VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
 +    BlockBackend *blk = vexp->export.blk;
      struct iovec *in_iov = elem->in_sg;
      struct iovec *out_iov = elem->out_sg;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
          bool is_write = type & VIRTIO_BLK_T_OUT;
          req->sector_num = le64_to_cpu(req->out.sector);
 -        int64_t offset = req->sector_num * vdev_blk->blk_size;
 +        if (is_write && !vexp->writable) {
 +            req->in->status = VIRTIO_BLK_S_IOERR;
 +            break;
 +        }
 +
 +        int64_t offset = req->sector_num * vexp->blk_size;
          QEMUIOVector qiov;
          if (is_write) {
              qemu_iovec_init_external(&qiov, out_iov, out_num);
 -            ret = blk_co_pwritev(backend, offset, qiov.size,
 -                                 &qiov, 0);
 +            ret = blk_co_pwritev(blk, offset, qiov.size, &qiov, 0);
          } else {
              qemu_iovec_init_external(&qiov, in_iov, in_num);
 -            ret = blk_co_preadv(backend, offset, qiov.size,
 -                                &qiov, 0);
 +            ret = blk_co_preadv(blk, offset, qiov.size, &qiov, 0);
          }
          if (ret >= 0) {
              req->in->status = VIRTIO_BLK_S_OK;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
          break;
      }
      case VIRTIO_BLK_T_FLUSH:
 -        if (vu_block_flush(req) == 0) {
 +        if (blk_co_flush(blk) == 0) {
              req->in->status = VIRTIO_BLK_S_OK;
          } else {
              req->in->status = VIRTIO_BLK_S_IOERR;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
      case VIRTIO_BLK_T_DISCARD:
      case VIRTIO_BLK_T_WRITE_ZEROES: {
          int rc;
 -        rc = vu_block_discard_write_zeroes(req, &elem->out_sg[1],
 -                                           out_num, type);
 +
 +        if (!vexp->writable) {
 +            req->in->status = VIRTIO_BLK_S_IOERR;
 +            break;
 +        }
 +
 +        rc = vu_blk_discard_write_zeroes(blk, &elem->out_sg[1], out_num, type);
          if (rc == 0) {
              req->in->status = VIRTIO_BLK_S_OK;
          } else {
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
          break;
      }
 -    vu_block_req_complete(req);
 +    vu_blk_req_complete(req);
      return;
  err:
 -    free(elem);
 +    free(req);
  }
 -static void vu_block_process_vq(VuDev *vu_dev, int idx)
 +static void vu_blk_process_vq(VuDev *vu_dev, int idx)
  {
      VuServer *server = container_of(vu_dev, VuServer, vu_dev);
      VuVirtq *vq = vu_get_queue(vu_dev, idx);
      while (1) {
 -        VuBlockReq *req;
 +        VuBlkReq *req;
 -        req = vu_queue_pop(vu_dev, vq, sizeof(VuBlockReq));
 +        req = vu_queue_pop(vu_dev, vq, sizeof(VuBlkReq));
          if (!req) {
              break;
          }
@@ -XXX,XX +XXX,XX @@ static void vu_block_process_vq(VuDev *vu_dev, int idx)
          req->vq = vq;
          Coroutine *co =
 -            qemu_coroutine_create(vu_block_virtio_process_req, req);
 +            qemu_coroutine_create(vu_blk_virtio_process_req, req);
          qemu_coroutine_enter(co);
      }
  }
 -static void vu_block_queue_set_started(VuDev *vu_dev, int idx, bool started)
 +static void vu_blk_queue_set_started(VuDev *vu_dev, int idx, bool started)
  {
      VuVirtq *vq;
      assert(vu_dev);
      vq = vu_get_queue(vu_dev, idx);
 -    vu_set_queue_handler(vu_dev, vq, started ? vu_block_process_vq : NULL);
 +    vu_set_queue_handler(vu_dev, vq, started ? vu_blk_process_vq : NULL);
  }
 -static uint64_t vu_block_get_features(VuDev *dev)
 +static uint64_t vu_blk_get_features(VuDev *dev)
  {
      uint64_t features;
      VuServer *server = container_of(dev, VuServer, vu_dev);
 -    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
 +    VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
      features = 1ull << VIRTIO_BLK_F_SIZE_MAX |
 ull << VIRTIO_BLK_F_SEG_MAX |
 ull << VIRTIO_BLK_F_TOPOLOGY |
@@ -XXX,XX +XXX,XX @@ static uint64_t vu_block_get_features(VuDev *dev)
 ull << VIRTIO_RING_F_EVENT_IDX |
 ull << VHOST_USER_F_PROTOCOL_FEATURES;
 -    if (!vdev_blk->writable) {
 +    if (!vexp->writable) {
          features |= 1ull << VIRTIO_BLK_F_RO;
      }
      return features;
  }
 -static uint64_t vu_block_get_protocol_features(VuDev *dev)
 +static uint64_t vu_blk_get_protocol_features(VuDev *dev)
  {
      return 1ull << VHOST_USER_PROTOCOL_F_CONFIG |
 ull << VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD;
  }
  static int
 -vu_block_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
 +vu_blk_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
  {
 +    /* TODO blkcfg must be little-endian for VIRTIO 1.0 */
      VuServer *server = container_of(vu_dev, VuServer, vu_dev);
 -    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
 -    memcpy(config, &vdev_blk->blkcfg, len);
 -
 +    VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
 +    memcpy(config, &vexp->blkcfg, len);
      return 0;
  }
  static int
 -vu_block_set_config(VuDev *vu_dev, const uint8_t *data,
 +vu_blk_set_config(VuDev *vu_dev, const uint8_t *data,
                      uint32_t offset, uint32_t size, uint32_t flags)
  {
      VuServer *server = container_of(vu_dev, VuServer, vu_dev);
 -    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
 +    VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
      uint8_t wce;
      /* don't support live migration */
@@ -XXX,XX +XXX,XX @@ vu_block_set_config(VuDev *vu_dev, const uint8_t *data,
      }
      wce = *data;
 -    vdev_blk->blkcfg.wce = wce;
 -    blk_set_enable_write_cache(vdev_blk->backend, wce);
 +    vexp->blkcfg.wce = wce;
 +    blk_set_enable_write_cache(vexp->export.blk, wce);
      return 0;
  }
@@ -XXX,XX +XXX,XX @@ vu_block_set_config(VuDev *vu_dev, const uint8_t *data,
   * of vu_process_message.
   *
   */
 -static int vu_block_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
 +static int vu_blk_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
  {
      if (vmsg->request == VHOST_USER_NONE) {
          dev->panic(dev, "disconnect");
@@ -XXX,XX +XXX,XX @@ static int vu_block_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
      return false;
  }
 -static const VuDevIface vu_block_iface = {
 -    .get_features          = vu_block_get_features,
 -    .queue_set_started     = vu_block_queue_set_started,
 -    .get_protocol_features = vu_block_get_protocol_features,
 -    .get_config            = vu_block_get_config,
 -    .set_config            = vu_block_set_config,
 -    .process_msg           = vu_block_process_msg,
 +static const VuDevIface vu_blk_iface = {
 +    .get_features          = vu_blk_get_features,
 +    .queue_set_started     = vu_blk_queue_set_started,
 +    .get_protocol_features = vu_blk_get_protocol_features,
 +    .get_config            = vu_blk_get_config,
 +    .set_config            = vu_blk_set_config,
 +    .process_msg           = vu_blk_process_msg,
  };
  static void blk_aio_attached(AioContext *ctx, void *opaque)
  {
 -    VuBlockDev *vub_dev = opaque;
 -    vhost_user_server_attach_aio_context(&vub_dev->vu_server, ctx);
 +    VuBlkExport *vexp = opaque;
 +    vhost_user_server_attach_aio_context(&vexp->vu_server, ctx);
  }
  static void blk_aio_detach(void *opaque)
  {
 -    VuBlockDev *vub_dev = opaque;
 -    vhost_user_server_detach_aio_context(&vub_dev->vu_server);
 +    VuBlkExport *vexp = opaque;
 +    vhost_user_server_detach_aio_context(&vexp->vu_server);
  }
  static void
 -vu_block_initialize_config(BlockDriverState *bs,
 +vu_blk_initialize_config(BlockDriverState *bs,
                             struct virtio_blk_config *config, uint32_t blk_size)
  {
      config->capacity = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
@@ -XXX,XX +XXX,XX @@ vu_block_initialize_config(BlockDriverState *bs,
      config->max_write_zeroes_seg = 1;
  }
 -static VuBlockDev *vu_block_init(VuBlockDev *vu_block_device, Error **errp)
 +static void vu_blk_exp_request_shutdown(BlockExport *exp)
  {
 +    VuBlkExport *vexp = container_of(exp, VuBlkExport, export);
 -    BlockBackend *blk;
 -    Error *local_error = NULL;
 -    const char *node_name = vu_block_device->node_name;
 -    bool writable = vu_block_device->writable;
 -    uint64_t perm = BLK_PERM_CONSISTENT_READ;
 -    int ret;
 -
 -    AioContext *ctx;
 -
 -    BlockDriverState *bs = bdrv_lookup_bs(node_name, node_name, &local_error);
 -
 -    if (!bs) {
 -        error_propagate(errp, local_error);
 -        return NULL;
 -    }
 -
 -    if (bdrv_is_read_only(bs)) {
 -        writable = false;
 -    }
 -
 -    if (writable) {
 -        perm |= BLK_PERM_WRITE;
 -    }
 -
 -    ctx = bdrv_get_aio_context(bs);
 -    aio_context_acquire(ctx);
 -    bdrv_invalidate_cache(bs, NULL);
 -    aio_context_release(ctx);
 -
 -    /*
 -     * Don't allow resize while the vhost user server is running,
 -     * otherwise we don't care what happens with the node.
 -     */
 -    blk = blk_new(bdrv_get_aio_context(bs), perm,
 -                  BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
 -                  BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
 -    ret = blk_insert_bs(blk, bs, errp);
 -
 -    if (ret < 0) {
 -        goto fail;
 -    }
 -
 -    blk_set_enable_write_cache(blk, false);
 -
 -    blk_set_allow_aio_context_change(blk, true);
 -
 -    vu_block_device->blkcfg.wce = 0;
 -    vu_block_device->backend = blk;
 -    if (!vu_block_device->blk_size) {
 -        vu_block_device->blk_size = BDRV_SECTOR_SIZE;
 -    }
 -    vu_block_device->blkcfg.blk_size = vu_block_device->blk_size;
 -    blk_set_guest_block_size(blk, vu_block_device->blk_size);
 -    vu_block_initialize_config(bs, &vu_block_device->blkcfg,
 -                                   vu_block_device->blk_size);
 -    return vu_block_device;
 -
 -fail:
 -    blk_unref(blk);
 -    return NULL;
 -}
 -
 -static void vu_block_deinit(VuBlockDev *vu_block_device)
 -{
 -    if (vu_block_device->backend) {
 -        blk_remove_aio_context_notifier(vu_block_device->backend, blk_aio_attached,
 -                                        blk_aio_detach, vu_block_device);
 -    }
 -
 -    blk_unref(vu_block_device->backend);
 -}
 -
 -static void vhost_user_blk_server_stop(VuBlockDev *vu_block_device)
 -{
 -    vhost_user_server_stop(&vu_block_device->vu_server);
 -    vu_block_deinit(vu_block_device);
 -}
 -
 -static void vhost_user_blk_server_start(VuBlockDev *vu_block_device,
 -                                        Error **errp)
 -{
 -    AioContext *ctx;
 -    SocketAddress *addr = vu_block_device->addr;
 -
 -    if (!vu_block_init(vu_block_device, errp)) {
 -        return;
 -    }
 -
 -    ctx = bdrv_get_aio_context(blk_bs(vu_block_device->backend));
 -
 -    if (!vhost_user_server_start(&vu_block_device->vu_server, addr, ctx,
 -                                 VHOST_USER_BLK_MAX_QUEUES, &vu_block_iface,
 -                                 errp)) {
 -        goto error;
 -    }
 -
 -    blk_add_aio_context_notifier(vu_block_device->backend, blk_aio_attached,
 -                                 blk_aio_detach, vu_block_device);
 -    vu_block_device->running = true;
 -    return;
 -
 - error:
 -    vu_block_deinit(vu_block_device);
 -}
 -
 -static bool vu_prop_modifiable(VuBlockDev *vus, Error **errp)
 -{
 -    if (vus->running) {
 -            error_setg(errp, "The property can't be modified "
 -                       "while the server is running");
 -            return false;
 -    }
 -    return true;
 -}
 -
 -static void vu_set_node_name(Object *obj, const char *value, Error **errp)
 -{
 -    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
 -
 -    if (!vu_prop_modifiable(vus, errp)) {
 -        return;
 -    }
 -
 -    if (vus->node_name) {
 -        g_free(vus->node_name);
 -    }
 -
 -    vus->node_name = g_strdup(value);
 -}
 -
 -static char *vu_get_node_name(Object *obj, Error **errp)
 -{
 -    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
 -    return g_strdup(vus->node_name);
 -}
 -
 -static void free_socket_addr(SocketAddress *addr)
 -{
 -        g_free(addr->u.q_unix.path);
 -        g_free(addr);
 -}
 -
 -static void vu_set_unix_socket(Object *obj, const char *value,
 -                               Error **errp)
 -{
 -    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
 -
 -    if (!vu_prop_modifiable(vus, errp)) {
 -        return;
 -    }
 -
 -    if (vus->addr) {
 -        free_socket_addr(vus->addr);
 -    }
 -
 -    SocketAddress *addr = g_new0(SocketAddress, 1);
 -    addr->type = SOCKET_ADDRESS_TYPE_UNIX;
 -    addr->u.q_unix.path = g_strdup(value);
 -    vus->addr = addr;
 +    vhost_user_server_stop(&vexp->vu_server);
  }
 -static char *vu_get_unix_socket(Object *obj, Error **errp)
 +static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
 +                             Error **errp)
  {
 -    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
 -    return g_strdup(vus->addr->u.q_unix.path);
 -}
 -
 -static bool vu_get_block_writable(Object *obj, Error **errp)
 -{
 -    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
 -    return vus->writable;
 -}
 -
 -static void vu_set_block_writable(Object *obj, bool value, Error **errp)
 -{
 -    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
 -
 -    if (!vu_prop_modifiable(vus, errp)) {
 -            return;
 -    }
 -
 -    vus->writable = value;
 -}
 -
 -static void vu_get_blk_size(Object *obj, Visitor *v, const char *name,
 -                            void *opaque, Error **errp)
 -{
 -    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
 -    uint32_t value = vus->blk_size;
 -
 -    visit_type_uint32(v, name, &value, errp);
 -}
 -
 -static void vu_set_blk_size(Object *obj, Visitor *v, const char *name,
 -                            void *opaque, Error **errp)
 -{
 -    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
 -
 +    VuBlkExport *vexp = container_of(exp, VuBlkExport, export);
 +    BlockExportOptionsVhostUserBlk *vu_opts = &opts->u.vhost_user_blk;
      Error *local_err = NULL;
 -    uint32_t value;
 +    uint64_t logical_block_size;
 -    if (!vu_prop_modifiable(vus, errp)) {
 -            return;
 -    }
 +    vexp->writable = opts->writable;
 +    vexp->blkcfg.wce = 0;
 -    visit_type_uint32(v, name, &value, &local_err);
 -    if (local_err) {
 -        goto out;
 +    if (vu_opts->has_logical_block_size) {
 +        logical_block_size = vu_opts->logical_block_size;
 +    } else {
 +        logical_block_size = BDRV_SECTOR_SIZE;
      }
 -
 -    check_block_size(object_get_typename(obj), name, value, &local_err);
 +    check_block_size(exp->id, "logical-block-size", logical_block_size,
 +                     &local_err);
      if (local_err) {
 -        goto out;
 +        error_propagate(errp, local_err);
 +        return -EINVAL;
 +    }
 +    vexp->blk_size = logical_block_size;
 +    blk_set_guest_block_size(exp->blk, logical_block_size);
 +    vu_blk_initialize_config(blk_bs(exp->blk), &vexp->blkcfg,
 +                               logical_block_size);
 +
 +    blk_set_allow_aio_context_change(exp->blk, true);
 +    blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
 +                                 vexp);
 +
 +    if (!vhost_user_server_start(&vexp->vu_server, vu_opts->addr, exp->ctx,
 +                                 VHOST_USER_BLK_MAX_QUEUES, &vu_blk_iface,
 +                                 errp)) {
 +        blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
 +                                        blk_aio_detach, vexp);
 +        return -EADDRNOTAVAIL;
      }
 -    vus->blk_size = value;
 -
 -out:
 -    error_propagate(errp, local_err);
 -}
 -
 -static void vhost_user_blk_server_instance_finalize(Object *obj)
 -{
 -    VuBlockDev *vub = VHOST_USER_BLK_SERVER(obj);
 -
 -    vhost_user_blk_server_stop(vub);
 -
 -    /*
 -     * Unlike object_property_add_str, object_class_property_add_str
 -     * doesn't have a release method. Thus manual memory freeing is
 -     * needed.
 -     */
 -    free_socket_addr(vub->addr);
 -    g_free(vub->node_name);
 -}
 -
 -static void vhost_user_blk_server_complete(UserCreatable *obj, Error **errp)
 -{
 -    VuBlockDev *vub = VHOST_USER_BLK_SERVER(obj);
 -
 -    vhost_user_blk_server_start(vub, errp);
 +    return 0;
  }
 -static void vhost_user_blk_server_class_init(ObjectClass *klass,
 -                                             void *class_data)
 +static void vu_blk_exp_delete(BlockExport *exp)
  {
 -    UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
 -    ucc->complete = vhost_user_blk_server_complete;
 -
 -    object_class_property_add_bool(klass, "writable",
 -                                   vu_get_block_writable,
 -                                   vu_set_block_writable);
 -
 -    object_class_property_add_str(klass, "node-name",
 -                                  vu_get_node_name,
 -                                  vu_set_node_name);
 -
 -    object_class_property_add_str(klass, "unix-socket",
 -                                  vu_get_unix_socket,
 -                                  vu_set_unix_socket);
 +    VuBlkExport *vexp = container_of(exp, VuBlkExport, export);
 -    object_class_property_add(klass, "logical-block-size", "uint32",
 -                              vu_get_blk_size, vu_set_blk_size,
 -                              NULL, NULL);
 +    blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
 +                                    vexp);
  }
 -static const TypeInfo vhost_user_blk_server_info = {
 -    .name = TYPE_VHOST_USER_BLK_SERVER,
 -    .parent = TYPE_OBJECT,
 -    .instance_size = sizeof(VuBlockDev),
 -    .instance_finalize = vhost_user_blk_server_instance_finalize,
 -    .class_init = vhost_user_blk_server_class_init,
 -    .interfaces = (InterfaceInfo[]) {
 -        {TYPE_USER_CREATABLE},
 -        {}
 -    },
 +const BlockExportDriver blk_exp_vhost_user_blk = {
 +    .type               = BLOCK_EXPORT_TYPE_VHOST_USER_BLK,
 +    .instance_size      = sizeof(VuBlkExport),
 +    .create             = vu_blk_exp_create,
 +    .delete             = vu_blk_exp_delete,
 +    .request_shutdown   = vu_blk_exp_request_shutdown,
  };
 -
 -static void vhost_user_blk_server_register_types(void)
 -{
 -    type_register_static(&vhost_user_blk_server_info);
 -}
 -
 -type_init(vhost_user_blk_server_register_types)
 diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/vhost-user-server.c
 +++ b/util/vhost-user-server.c
@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
                               Error **errp)
  {
      QEMUBH *bh;
 -    QIONetListener *listener = qio_net_listener_new();
 +    QIONetListener *listener;
 +
 +    if (socket_addr->type != SOCKET_ADDRESS_TYPE_UNIX &&
 +        socket_addr->type != SOCKET_ADDRESS_TYPE_FD) {
 +        error_setg(errp, "Only socket address types 'unix' and 'fd' are supported");
 +        return false;
 +    }
 +
 +    listener = qio_net_listener_new();
      if (qio_net_listener_open_sync(listener, socket_addr, 1,
                                     errp) < 0) {
          object_unref(OBJECT(listener));
 diff --git a/block/export/meson.build b/block/export/meson.build
 index XXXXXXX..XXXXXXX 100644
 --- a/block/export/meson.build
 +++ b/block/export/meson.build
@@ -1 +1,2 @@
  block_ss.add(files('export.c'))
 +block_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-blk-server.c', '../../contrib/libvhost-user/libvhost-user.c'))
 diff --git a/block/meson.build b/block/meson.build
 index XXXXXXX..XXXXXXX 100644
 --- a/block/meson.build
 +++ b/block/meson.build
@@ -XXX,XX +XXX,XX @@ block_ss.add(when: 'CONFIG_WIN32', if_true: files('file-win32.c', 'win32-aio.c')
  block_ss.add(when: 'CONFIG_POSIX', if_true: [files('file-posix.c'), coref, iokit])
  block_ss.add(when: 'CONFIG_LIBISCSI', if_true: files('iscsi-opts.c'))
  block_ss.add(when: 'CONFIG_LINUX', if_true: files('nvme.c'))
 -block_ss.add(when: 'CONFIG_LINUX', if_true: files('export/vhost-user-blk-server.c', '../contrib/libvhost-user/libvhost-user.c'))
  block_ss.add(when: 'CONFIG_REPLICATION', if_true: files('replication.c'))
  block_ss.add(when: 'CONFIG_SHEEPDOG', if_true: files('sheepdog.c'))
  block_ss.add(when: ['CONFIG_LINUX_AIO', libaio], if_true: files('linux-aio.c'))
 --
 .26.2

-New patch
+[PULL v2 18/28] util/vhost-user-server: move header to include/
+Headers used by other subsystems are located in include/. Also add the
+vhost-user-server and vhost-user-blk-server headers to MAINTAINERS.
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200924151549.913737-13-stefanha@redhat.com
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ MAINTAINERS                                | 4 +++-
+ {util => include/qemu}/vhost-user-server.h | 0
+ block/export/vhost-user-blk-server.c       | 2 +-
+ util/vhost-user-server.c                   | 2 +-
+files changed, 5 insertions(+), 3 deletions(-)
+ rename {util => include/qemu}/vhost-user-server.h (100%)
+diff --git a/MAINTAINERS b/MAINTAINERS
+index XXXXXXX..XXXXXXX 100644
+--- a/MAINTAINERS
++++ b/MAINTAINERS
+@@ -XXX,XX +XXX,XX @@ Vhost-user block device backend server
+ M: Coiby Xu <Coiby.Xu@gmail.com>
+ S: Maintained
+ F: block/export/vhost-user-blk-server.c
+-F: util/vhost-user-server.c
++F: block/export/vhost-user-blk-server.h
++F: include/qemu/vhost-user-server.h
+ F: tests/qtest/libqos/vhost-user-blk.c
++F: util/vhost-user-server.c
+ Replication
+ M: Wen Congyang <wencongyang2@huawei.com>
+diff --git a/util/vhost-user-server.h b/include/qemu/vhost-user-server.h
+similarity index 100%
+rename from util/vhost-user-server.h
+rename to include/qemu/vhost-user-server.h
+diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/block/export/vhost-user-blk-server.c
++++ b/block/export/vhost-user-blk-server.c
+@@ -XXX,XX +XXX,XX @@
+ #include "block/block.h"
+ #include "contrib/libvhost-user/libvhost-user.h"
+ #include "standard-headers/linux/virtio_blk.h"
+-#include "util/vhost-user-server.h"
++#include "qemu/vhost-user-server.h"
+ #include "vhost-user-blk-server.h"
+ #include "qapi/error.h"
+ #include "qom/object_interfaces.h"
+diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/util/vhost-user-server.c
++++ b/util/vhost-user-server.c
+@@ -XXX,XX +XXX,XX @@
+  */
+ #include "qemu/osdep.h"
+ #include "qemu/main-loop.h"
++#include "qemu/vhost-user-server.h"
+ #include "block/aio-wait.h"
+-#include "vhost-user-server.h"
+ /*
+  * Theory of operation:
+--
+.26.2

-New patch
+[PULL v2 19/28] util/vhost-user-server: use static library in meson.build
+Don't compile contrib/libvhost-user/libvhost-user.c again. Instead build
+the static library once and then reuse it throughout QEMU.
+Also switch from CONFIG_LINUX to CONFIG_VHOST_USER, which is what the
+vhost-user tools (vhost-user-gpu, etc) do.
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200924151549.913737-14-stefanha@redhat.com
+[Added CONFIG_LINUX again because libvhost-user doesn't build on macOS.
+--Stefan]
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ block/export/export.c             | 8 ++++----
+ block/export/meson.build          | 2 +-
+ contrib/libvhost-user/meson.build | 1 +
+ meson.build                       | 6 +++++-
+ util/meson.build                  | 4 +++-
+files changed, 14 insertions(+), 7 deletions(-)
+diff --git a/block/export/export.c b/block/export/export.c
+index XXXXXXX..XXXXXXX 100644
+--- a/block/export/export.c
++++ b/block/export/export.c
+@@ -XXX,XX +XXX,XX @@
+ #include "sysemu/block-backend.h"
+ #include "block/export.h"
+ #include "block/nbd.h"
+-#if CONFIG_LINUX
+-#include "block/export/vhost-user-blk-server.h"
+-#endif
+ #include "qapi/error.h"
+ #include "qapi/qapi-commands-block-export.h"
+ #include "qapi/qapi-events-block-export.h"
+ #include "qemu/id.h"
++#ifdef CONFIG_VHOST_USER
++#include "vhost-user-blk-server.h"
++#endif
+ static const BlockExportDriver *blk_exp_drivers[] = {
+     &blk_exp_nbd,
+-#if CONFIG_LINUX
++#ifdef CONFIG_VHOST_USER
+     &blk_exp_vhost_user_blk,
+ #endif
+ };
+diff --git a/block/export/meson.build b/block/export/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/block/export/meson.build
++++ b/block/export/meson.build
+@@ -XXX,XX +XXX,XX @@
+ block_ss.add(files('export.c'))
+-block_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-blk-server.c', '../../contrib/libvhost-user/libvhost-user.c'))
++block_ss.add(when: ['CONFIG_LINUX', 'CONFIG_VHOST_USER'], if_true: files('vhost-user-blk-server.c'))
+diff --git a/contrib/libvhost-user/meson.build b/contrib/libvhost-user/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/contrib/libvhost-user/meson.build
++++ b/contrib/libvhost-user/meson.build
+@@ -XXX,XX +XXX,XX @@
+ libvhost_user = static_library('vhost-user',
+                                files('libvhost-user.c', 'libvhost-user-glib.c'),
+                                build_by_default: false)
++vhost_user = declare_dependency(link_with: libvhost_user)
+diff --git a/meson.build b/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/meson.build
++++ b/meson.build
+@@ -XXX,XX +XXX,XX @@ trace_events_subdirs += [
+   'util',
+ ]
++vhost_user = not_found
++if 'CONFIG_VHOST_USER' in config_host
++  subdir('contrib/libvhost-user')
++endif
++
+ subdir('qapi')
+ subdir('qobject')
+ subdir('stubs')
+@@ -XXX,XX +XXX,XX @@ if have_tools
+              install: true)
+   if 'CONFIG_VHOST_USER' in config_host
+-    subdir('contrib/libvhost-user')
+     subdir('contrib/vhost-user-blk')
+     subdir('contrib/vhost-user-gpu')
+     subdir('contrib/vhost-user-input')
+diff --git a/util/meson.build b/util/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/util/meson.build
++++ b/util/meson.build
+@@ -XXX,XX +XXX,XX @@ if have_block
+   util_ss.add(files('main-loop.c'))
+   util_ss.add(files('nvdimm-utils.c'))
+   util_ss.add(files('qemu-coroutine.c', 'qemu-coroutine-lock.c', 'qemu-coroutine-io.c'))
+-  util_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-server.c'))
++  util_ss.add(when: ['CONFIG_LINUX', 'CONFIG_VHOST_USER'], if_true: [
++    files('vhost-user-server.c'), vhost_user
++  ])
+   util_ss.add(files('block-helpers.c'))
+   util_ss.add(files('qemu-coroutine-sleep.c'))
+   util_ss.add(files('qemu-co-shared-resource.c'))
+--
+.26.2

-[Qemu-devel] [PULL 11/12] block/qcow2: implement .bdrv_co_preadv_part
+[PULL v2 20/28] qemu-storage-daemon: avoid compiling blockdev_ss twice
-From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+Introduce libblkdev.fa to avoid recompiling blockdev_ss twice.
-Implement and use new interface to get rid of hd_qiov.
+Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
+Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
-Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200929125516.186715-3-stefanha@redhat.com
 Message-id: 20190604161514.262241-12-vsementsov@virtuozzo.com
 Message-Id: <20190604161514.262241-12-vsementsov@virtuozzo.com>
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- block/qcow2-cluster.c |  5 +++--
+ meson.build                | 12 ++++++++++--
- block/qcow2.c         | 49 +++++++++++++++++++------------------------
+ storage-daemon/meson.build |  3 +--
-files changed, 25 insertions(+), 29 deletions(-)
+files changed, 11 insertions(+), 4 deletions(-)
-diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
+diff --git a/meson.build b/meson.build
 index XXXXXXX..XXXXXXX 100644
---- a/block/qcow2-cluster.c
+--- a/meson.build
-+++ b/block/qcow2-cluster.c
++++ b/meson.build
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn do_perform_cow_read(BlockDriverState *bs,
+@@ -XXX,XX +XXX,XX @@ blockdev_ss.add(files(
-      * interface.  This avoids double I/O throttling and request tracking,
+ # os-win32.c does not
-      * which can lead to deadlock when block layer copy-on-read is enabled.
+ blockdev_ss.add(when: 'CONFIG_POSIX', if_true: files('os-posix.c'))
-      */
+ softmmu_ss.add(when: 'CONFIG_WIN32', if_true: [files('os-win32.c')])
--    ret = bs->drv->bdrv_co_preadv(bs, src_cluster_offset + offset_in_cluster,
+-softmmu_ss.add_all(blockdev_ss)
--                                  qiov->size, qiov, 0);
-+    ret = bs->drv->bdrv_co_preadv_part(bs,
+ common_ss.add(files('cpus-common.c'))
-+                                       src_cluster_offset + offset_in_cluster,
-+                                       qiov->size, qiov, 0, 0);
+@@ -XXX,XX +XXX,XX @@ block = declare_dependency(link_whole: [libblock],
-     if (ret < 0) {
+                            link_args: '@block.syms',
-         return ret;
+                            dependencies: [crypto, io])
-     }
-diff --git a/block/qcow2.c b/block/qcow2.c
++blockdev_ss = blockdev_ss.apply(config_host, strict: false)
 +libblockdev = static_library('blockdev', blockdev_ss.sources() + genh,
 +                             dependencies: blockdev_ss.dependencies(),
 +                             name_suffix: 'fa',
 +                             build_by_default: false)
 +
 +blockdev = declare_dependency(link_whole: [libblockdev],
 +                              dependencies: [block])
 +
  qmp_ss = qmp_ss.apply(config_host, strict: false)
  libqmp = static_library('qmp', qmp_ss.sources() + genh,
                          dependencies: qmp_ss.dependencies(),
@@ -XXX,XX +XXX,XX @@ foreach m : block_mods + softmmu_mods
                  install_dir: config_host['qemu_moddir'])
  endforeach
 -softmmu_ss.add(authz, block, chardev, crypto, io, qmp)
 +softmmu_ss.add(authz, blockdev, chardev, crypto, io, qmp)
  common_ss.add(qom, qemuutil)
  common_ss.add_all(when: 'CONFIG_SOFTMMU', if_true: [softmmu_ss])
 diff --git a/storage-daemon/meson.build b/storage-daemon/meson.build
 index XXXXXXX..XXXXXXX 100644
---- a/block/qcow2.c
+--- a/storage-daemon/meson.build
-+++ b/block/qcow2.c
++++ b/storage-daemon/meson.build
-@@ -XXX,XX +XXX,XX @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
+@@ -XXX,XX +XXX,XX @@
-                            uint64_t file_cluster_offset,
+ qsd_ss = ss.source_set()
-                            uint64_t offset,
+ qsd_ss.add(files('qemu-storage-daemon.c'))
-                            uint64_t bytes,
+-qsd_ss.add(block, chardev, qmp, qom, qemuutil)
--                           QEMUIOVector *qiov);
+-qsd_ss.add_all(blockdev_ss)
-+                           QEMUIOVector *qiov,
++qsd_ss.add(blockdev, chardev, qmp, qom, qemuutil)
-+                           size_t qiov_offset);
+ subdir('qapi')
  static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
  {
@@ -XXX,XX +XXX,XX @@ out:
      return ret;
  }
 -static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
 -                                        uint64_t bytes, QEMUIOVector *qiov,
 -                                        int flags)
 +static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs,
 +                                             uint64_t offset, uint64_t bytes,
 +                                             QEMUIOVector *qiov,
 +                                             size_t qiov_offset, int flags)
  {
      BDRVQcow2State *s = bs->opaque;
      int offset_in_cluster;
      int ret;
      unsigned int cur_bytes; /* number of bytes in current iteration */
      uint64_t cluster_offset = 0;
 -    uint64_t bytes_done = 0;
 -    QEMUIOVector hd_qiov;
      uint8_t *cluster_data = NULL;
 -    qemu_iovec_init(&hd_qiov, qiov->niov);
 -
      while (bytes != 0) {
          /* prepare next request */
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
          offset_in_cluster = offset_into_cluster(s, offset);
 -        qemu_iovec_reset(&hd_qiov);
 -        qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
 -
          switch (ret) {
          case QCOW2_CLUSTER_UNALLOCATED:
              if (bs->backing) {
                  BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
 -                ret = bdrv_co_preadv(bs->backing, offset, cur_bytes,
 -                                     &hd_qiov, 0);
 +                ret = bdrv_co_preadv_part(bs->backing, offset, cur_bytes,
 +                                          qiov, qiov_offset, 0);
                  if (ret < 0) {
                      goto fail;
                  }
              } else {
                  /* Note: in this case, no need to wait */
 -                qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
 +                qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes);
              }
              break;
          case QCOW2_CLUSTER_ZERO_PLAIN:
          case QCOW2_CLUSTER_ZERO_ALLOC:
 -            qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
 +            qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes);
              break;
          case QCOW2_CLUSTER_COMPRESSED:
              ret = qcow2_co_preadv_compressed(bs, cluster_offset,
                                               offset, cur_bytes,
 -                                             &hd_qiov);
 +                                             qiov, qiov_offset);
              if (ret < 0) {
                  goto fail;
              }
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
                      ret = -EIO;
                      goto fail;
                  }
 -                qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes);
 +                qemu_iovec_from_buf(qiov, qiov_offset, cluster_data, cur_bytes);
              } else {
                  BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
 -                ret = bdrv_co_preadv(s->data_file,
 -                                     cluster_offset + offset_in_cluster,
 -                                     cur_bytes, &hd_qiov, 0);
 +                ret = bdrv_co_preadv_part(s->data_file,
 +                                          cluster_offset + offset_in_cluster,
 +                                          cur_bytes, qiov, qiov_offset, 0);
                  if (ret < 0) {
                      goto fail;
                  }
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
          bytes -= cur_bytes;
          offset += cur_bytes;
 -        bytes_done += cur_bytes;
 +        qiov_offset += cur_bytes;
      }
      ret = 0;
  fail:
 -    qemu_iovec_destroy(&hd_qiov);
      qemu_vfree(cluster_data);
      return ret;
@@ -XXX,XX +XXX,XX @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
                             uint64_t file_cluster_offset,
                             uint64_t offset,
                             uint64_t bytes,
 -                           QEMUIOVector *qiov)
 +                           QEMUIOVector *qiov,
 +                           size_t qiov_offset)
  {
      BDRVQcow2State *s = bs->opaque;
      int ret = 0, csize, nb_csectors;
@@ -XXX,XX +XXX,XX @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
          goto fail;
      }
 -    qemu_iovec_from_buf(qiov, 0, out_buf + offset_in_cluster, bytes);
 +    qemu_iovec_from_buf(qiov, qiov_offset, out_buf + offset_in_cluster, bytes);
  fail:
      qemu_vfree(out_buf);
@@ -XXX,XX +XXX,XX @@ static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
      BDRVQcow2State *s = bs->opaque;
      BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
 -    return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos,
 -                                   qiov->size, qiov, 0);
 +    return bs->drv->bdrv_co_preadv_part(bs, qcow2_vm_state_offset(s) + pos,
 +                                        qiov->size, qiov, 0, 0);
  }
  /*
@@ -XXX,XX +XXX,XX @@ BlockDriver bdrv_qcow2 = {
      .bdrv_has_zero_init_truncate = bdrv_has_zero_init_1,
      .bdrv_co_block_status = qcow2_co_block_status,
 -    .bdrv_co_preadv         = qcow2_co_preadv,
 +    .bdrv_co_preadv_part    = qcow2_co_preadv_part,
      .bdrv_co_pwritev        = qcow2_co_pwritev,
      .bdrv_co_flush_to_os    = qcow2_co_flush_to_os,
 --
-.21.0
+.26.2

-New patch
+[PULL v2 21/28] block: move block exports to libblockdev
+Block exports are used by softmmu, qemu-storage-daemon, and qemu-nbd.
+They are not used by other programs and are not otherwise needed in
+libblock.
+Undo the recent move of blockdev-nbd.c from blockdev_ss into block_ss.
+Since bdrv_close_all() (libblock) calls blk_exp_close_all()
+(libblockdev) a stub function is required..
+Make qemu-nbd.c use signal handling utility functions instead of
+duplicating the code. This helps because os-posix.c is in libblockdev
+and it depends on a qemu_system_killed() symbol that qemu-nbd.c lacks.
+Once we use the signal handling utility functions we also end up
+providing the necessary symbol.
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
+Reviewed-by: Eric Blake <eblake@redhat.com>
+Message-id: 20200929125516.186715-4-stefanha@redhat.com
+[Fixed s/ndb/nbd/ typo in commit description as suggested by Eric Blake
+--Stefan]
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ qemu-nbd.c                | 21 ++++++++-------------
+ stubs/blk-exp-close-all.c |  7 +++++++
+ block/export/meson.build  |  4 ++--
+ meson.build               |  4 ++--
+ nbd/meson.build           |  2 ++
+ stubs/meson.build         |  1 +
+files changed, 22 insertions(+), 17 deletions(-)
+ create mode 100644 stubs/blk-exp-close-all.c
+diff --git a/qemu-nbd.c b/qemu-nbd.c
+index XXXXXXX..XXXXXXX 100644
+--- a/qemu-nbd.c
++++ b/qemu-nbd.c
+@@ -XXX,XX +XXX,XX @@
+ #include "qapi/error.h"
+ #include "qemu/cutils.h"
+ #include "sysemu/block-backend.h"
++#include "sysemu/runstate.h" /* for qemu_system_killed() prototype */
+ #include "block/block_int.h"
+ #include "block/nbd.h"
+ #include "qemu/main-loop.h"
+@@ -XXX,XX +XXX,XX @@ QEMU_COPYRIGHT "\n"
+ }
+ #ifdef CONFIG_POSIX
+-static void termsig_handler(int signum)
++/*
++ * The client thread uses SIGTERM to interrupt the server.  A signal
++ * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
++ */
++void qemu_system_killed(int signum, pid_t pid)
+ {
+     qatomic_cmpxchg(&state, RUNNING, TERMINATE);
+     qemu_notify_event();
+@@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv)
+     BlockExportOptions *export_opts;
+ #ifdef CONFIG_POSIX
+-    /*
+-     * Exit gracefully on various signals, which includes SIGTERM used
+-     * by 'qemu-nbd -v -c'.
+-     */
+-    struct sigaction sa_sigterm;
+-    memset(&sa_sigterm, 0, sizeof(sa_sigterm));
+-    sa_sigterm.sa_handler = termsig_handler;
+-    sigaction(SIGTERM, &sa_sigterm, NULL);
+-    sigaction(SIGINT, &sa_sigterm, NULL);
+-    sigaction(SIGHUP, &sa_sigterm, NULL);
+-
+-    signal(SIGPIPE, SIG_IGN);
++    os_setup_early_signal_handling();
++    os_setup_signal_handling();
+ #endif
+     socket_init();
+diff --git a/stubs/blk-exp-close-all.c b/stubs/blk-exp-close-all.c
+new file mode 100644
+index XXXXXXX..XXXXXXX
+--- /dev/null
++++ b/stubs/blk-exp-close-all.c
+@@ -XXX,XX +XXX,XX @@
++#include "qemu/osdep.h"
++#include "block/export.h"
++
++/* Only used in programs that support block exports (libblockdev.fa) */
++void blk_exp_close_all(void)
++{
++}
+diff --git a/block/export/meson.build b/block/export/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/block/export/meson.build
++++ b/block/export/meson.build
+@@ -XXX,XX +XXX,XX @@
+-block_ss.add(files('export.c'))
+-block_ss.add(when: ['CONFIG_LINUX', 'CONFIG_VHOST_USER'], if_true: files('vhost-user-blk-server.c'))
++blockdev_ss.add(files('export.c'))
++blockdev_ss.add(when: ['CONFIG_LINUX', 'CONFIG_VHOST_USER'], if_true: files('vhost-user-blk-server.c'))
+diff --git a/meson.build b/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/meson.build
++++ b/meson.build
+@@ -XXX,XX +XXX,XX @@ subdir('dump')
+ block_ss.add(files(
+   'block.c',
+-  'blockdev-nbd.c',
+   'blockjob.c',
+   'job.c',
+   'qemu-io-cmds.c',
+@@ -XXX,XX +XXX,XX @@ subdir('block')
+ blockdev_ss.add(files(
+   'blockdev.c',
++  'blockdev-nbd.c',
+   'iothread.c',
+   'job-qmp.c',
+ ))
+@@ -XXX,XX +XXX,XX @@ if have_tools
+   qemu_io = executable('qemu-io', files('qemu-io.c'),
+              dependencies: [block, qemuutil], install: true)
+   qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
+-               dependencies: [block, qemuutil], install: true)
++               dependencies: [blockdev, qemuutil], install: true)
+   subdir('storage-daemon')
+   subdir('contrib/rdmacm-mux')
+diff --git a/nbd/meson.build b/nbd/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/nbd/meson.build
++++ b/nbd/meson.build
+@@ -XXX,XX +XXX,XX @@
+ block_ss.add(files(
+   'client.c',
+   'common.c',
++))
++blockdev_ss.add(files(
+   'server.c',
+ ))
+diff --git a/stubs/meson.build b/stubs/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/stubs/meson.build
++++ b/stubs/meson.build
+@@ -XXX,XX +XXX,XX @@
+ stub_ss.add(files('arch_type.c'))
+ stub_ss.add(files('bdrv-next-monitor-owned.c'))
+ stub_ss.add(files('blk-commit-all.c'))
++stub_ss.add(files('blk-exp-close-all.c'))
+ stub_ss.add(files('blockdev-close-all-bdrv-states.c'))
+ stub_ss.add(files('change-state-handler.c'))
+ stub_ss.add(files('cmos.c'))
+--
+.26.2

-[Qemu-devel] [PULL 08/12] block/io: bdrv_aligned_pwritev: use and support qiov_offset
+[PULL v2 22/28] block/export: add iothread and fixed-iothread options
-From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+Make it possible to specify the iothread where the export will run. By
 default the block node can be moved to other AioContexts later and the
 export will follow. The fixed-iothread option forces strict behavior
 that prevents changing AioContext while the export is active. See the
 QAPI docs for details.
-Use and support new API in bdrv_aligned_pwritev.
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20200929125516.186715-5-stefanha@redhat.com
-Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+[Fix stray '#' character in block-export.json and add missing "(since:
-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
+.2)" as suggested by Eric Blake.
-Message-id: 20190604161514.262241-9-vsementsov@virtuozzo.com
+--Stefan]
 Message-Id: <20190604161514.262241-9-vsementsov@virtuozzo.com>
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- block/io.c | 27 +++++++++++++--------------
+ qapi/block-export.json               | 11 ++++++++++
-file changed, 13 insertions(+), 14 deletions(-)
+ block/export/export.c                | 31 +++++++++++++++++++++++++++-
  block/export/vhost-user-blk-server.c |  5 ++++-
  nbd/server.c                         |  2 --
 files changed, 45 insertions(+), 4 deletions(-)
-diff --git a/block/io.c b/block/io.c
+diff --git a/qapi/block-export.json b/qapi/block-export.json
 index XXXXXXX..XXXXXXX 100644
---- a/block/io.c
+--- a/qapi/block-export.json
-+++ b/block/io.c
++++ b/qapi/block-export.json
-@@ -XXX,XX +XXX,XX @@ bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, uint64_t bytes,
+@@ -XXX,XX +XXX,XX @@
-  */
+ #                export before completion is signalled. (since: 5.2;
- static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
+ #                default: false)
-     BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
+ #
--    int64_t align, QEMUIOVector *qiov, int flags)
++# @iothread: The name of the iothread object where the export will run. The
-+    int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
++#            default is to use the thread currently associated with the
 +#            block node. (since: 5.2)
 +#
 +# @fixed-iothread: True prevents the block node from being moved to another
 +#                  thread while the export is active. If true and @iothread is
 +#                  given, export creation fails if the block node cannot be
 +#                  moved to the iothread. The default is false. (since: 5.2)
 +#
  # Since: 4.2
  ##
  { 'union': 'BlockExportOptions',
    'base': { 'type': 'BlockExportType',
              'id': 'str',
 +        '*fixed-iothread': 'bool',
 +        '*iothread': 'str',
              'node-name': 'str',
              '*writable': 'bool',
              '*writethrough': 'bool' },
 diff --git a/block/export/export.c b/block/export/export.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/export/export.c
 +++ b/block/export/export.c
@@ -XXX,XX +XXX,XX @@
  #include "block/block.h"
  #include "sysemu/block-backend.h"
 +#include "sysemu/iothread.h"
  #include "block/export.h"
  #include "block/nbd.h"
  #include "qapi/error.h"
@@ -XXX,XX +XXX,XX @@ static const BlockExportDriver *blk_exp_find_driver(BlockExportType type)
  BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
  {
-     BlockDriverState *bs = child->bs;
++    bool fixed_iothread = export->has_fixed_iothread && export->fixed_iothread;
-     BlockDriver *drv = bs->drv;
+     const BlockExportDriver *drv;
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
+     BlockExport *exp = NULL;
-     assert(is_power_of_2(align));
+     BlockDriverState *bs;
-     assert((offset & (align - 1)) == 0);
+-    BlockBackend *blk;
-     assert((bytes & (align - 1)) == 0);
++    BlockBackend *blk = NULL;
--    assert(!qiov || bytes == qiov->size);
+     AioContext *ctx;
-+    assert(!qiov || qiov_offset + bytes <= qiov->size);
+     uint64_t perm;
-     max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX),
+     int ret;
-                                    align);
+@@ -XXX,XX +XXX,XX @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
+     ctx = bdrv_get_aio_context(bs);
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
+     aio_context_acquire(ctx);
-     if (!ret && bs->detect_zeroes != BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF &&
++    if (export->has_iothread) {
-         !(flags & BDRV_REQ_ZERO_WRITE) && drv->bdrv_co_pwrite_zeroes &&
++        IOThread *iothread;
--        qemu_iovec_is_zero(qiov, 0, qiov->size)) {
++        AioContext *new_ctx;
-+        qemu_iovec_is_zero(qiov, qiov_offset, bytes)) {
++
-         flags |= BDRV_REQ_ZERO_WRITE;
++        iothread = iothread_by_id(export->iothread);
-         if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) {
++        if (!iothread) {
-             flags |= BDRV_REQ_MAY_UNMAP;
++            error_setg(errp, "iothread \"%s\" not found", export->iothread);
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
++            goto fail;
-         bdrv_debug_event(bs, BLKDBG_PWRITEV_ZERO);
++        }
-         ret = bdrv_co_do_pwrite_zeroes(bs, offset, bytes, flags);
++
-     } else if (flags & BDRV_REQ_WRITE_COMPRESSED) {
++        new_ctx = iothread_get_aio_context(iothread);
--        ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, qiov, 0);
++
-+        ret = bdrv_driver_pwritev_compressed(bs, offset, bytes,
++        ret = bdrv_try_set_aio_context(bs, new_ctx, errp);
-+                                             qiov, qiov_offset);
++        if (ret == 0) {
-     } else if (bytes <= max_transfer) {
++            aio_context_release(ctx);
-         bdrv_debug_event(bs, BLKDBG_PWRITEV);
++            aio_context_acquire(new_ctx);
--        ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, 0, flags);
++            ctx = new_ctx;
-+        ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, qiov_offset, flags);
++        } else if (fixed_iothread) {
-     } else {
++            goto fail;
-         bdrv_debug_event(bs, BLKDBG_PWRITEV);
++        }
-         while (bytes_remaining) {
++    }
-             int num = MIN(bytes_remaining, max_transfer);
++
--            QEMUIOVector local_qiov;
+     /*
-             int local_flags = flags;
+      * Block exports are used for non-shared storage migration. Make sure
+      * that BDRV_O_INACTIVE is cleared and the image is ready for write
-             assert(num);
+@@ -XXX,XX +XXX,XX @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
                   * need to flush on the last iteration */
                  local_flags &= ~BDRV_REQ_FUA;
              }
 -            qemu_iovec_init(&local_qiov, qiov->niov);
 -            qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
              ret = bdrv_driver_pwritev(bs, offset + bytes - bytes_remaining,
 -                                      num, &local_qiov, 0, local_flags);
 -            qemu_iovec_destroy(&local_qiov);
 +                                      num, qiov, bytes - bytes_remaining,
 +                                      local_flags);
              if (ret < 0) {
                  break;
              }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
              qemu_iovec_init_buf(&local_qiov, pad.buf, write_bytes);
              ret = bdrv_aligned_pwritev(child, req, aligned_offset, write_bytes,
 -                                       align, &local_qiov,
 +                                       align, &local_qiov, 0,
                                         flags & ~BDRV_REQ_ZERO_WRITE);
              if (ret < 0 || pad.merge_reads) {
                  /* Error or all work is done */
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
          /* Write the aligned part in the middle. */
          uint64_t aligned_bytes = bytes & ~(align - 1);
          ret = bdrv_aligned_pwritev(child, req, offset, aligned_bytes, align,
 -                                   NULL, flags);
 +                                   NULL, 0, flags);
          if (ret < 0) {
              goto out;
          }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
          qemu_iovec_init_buf(&local_qiov, pad.tail_buf, align);
          ret = bdrv_aligned_pwritev(child, req, offset, align, align,
 -                                   &local_qiov, flags & ~BDRV_REQ_ZERO_WRITE);
 +                                   &local_qiov, 0,
 +                                   flags & ~BDRV_REQ_ZERO_WRITE);
      }
- out:
+     blk = blk_new(ctx, perm, BLK_PERM_ALL);
-@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
++
 +    if (!fixed_iothread) {
 +        blk_set_allow_aio_context_change(blk, true);
 +    }
 +
      ret = blk_insert_bs(blk, bs, errp);
      if (ret < 0) {
          goto fail;
 diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/export/vhost-user-blk-server.c
 +++ b/block/export/vhost-user-blk-server.c
@@ -XXX,XX +XXX,XX @@ static const VuDevIface vu_blk_iface = {
  static void blk_aio_attached(AioContext *ctx, void *opaque)
  {
      VuBlkExport *vexp = opaque;
 +
 +    vexp->export.ctx = ctx;
      vhost_user_server_attach_aio_context(&vexp->vu_server, ctx);
  }
  static void blk_aio_detach(void *opaque)
  {
      VuBlkExport *vexp = opaque;
 +
      vhost_user_server_detach_aio_context(&vexp->vu_server);
 +    vexp->export.ctx = NULL;
  }
  static void
@@ -XXX,XX +XXX,XX @@ static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
      vu_blk_initialize_config(blk_bs(exp->blk), &vexp->blkcfg,
                                 logical_block_size);
 -    blk_set_allow_aio_context_change(exp->blk, true);
      blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
                                   vexp);
 diff --git a/nbd/server.c b/nbd/server.c
 index XXXXXXX..XXXXXXX 100644
 --- a/nbd/server.c
 +++ b/nbd/server.c
@@ -XXX,XX +XXX,XX @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args,
          return ret;
      }
-     ret = bdrv_aligned_pwritev(child, &req, offset, bytes, align,
+-    blk_set_allow_aio_context_change(blk, true);
--                               qiov, flags);
+-
-+                               qiov, 0, flags);
+     QTAILQ_INIT(&exp->clients);
+     exp->name = g_strdup(arg->name);
-     bdrv_padding_destroy(&pad);
+     exp->description = g_strdup(arg->description);
 --
-.21.0
+.26.2

-New patch
+[PULL v2 23/28] block/export: add vhost-user-blk multi-queue support
+Allow the number of queues to be configured using --export
+vhost-user-blk,num-queues=N. This setting should match the QEMU --device
+vhost-user-blk-pci,num-queues=N setting but QEMU vhost-user-blk.c lowers
+its own value if the vhost-user-blk backend offers fewer queues than
+QEMU.
+The vhost-user-blk-server.c code is already capable of multi-queue. All
+virtqueue processing runs in the same AioContext. No new locking is
+needed.
+Add the num-queues=N option and set the VIRTIO_BLK_F_MQ feature bit.
+Note that the feature bit only announces the presence of the num_queues
+configuration space field. It does not promise that there is more than 1
+virtqueue, so we can set it unconditionally.
+I tested multi-queue by running a random read fio test with numjobs=4 on
+an -smp 4 guest. After the benchmark finished the guest /proc/interrupts
+file showed activity on all 4 virtio-blk MSI-X. The /sys/block/vda/mq/
+directory shows that Linux blk-mq has 4 queues configured.
+An automated test is included in the next commit.
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Acked-by: Markus Armbruster <armbru@redhat.com>
+Message-id: 20201001144604.559733-2-stefanha@redhat.com
+[Fixed accidental tab characters as suggested by Markus Armbruster
+--Stefan]
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ qapi/block-export.json               | 10 +++++++---
+ block/export/vhost-user-blk-server.c | 24 ++++++++++++++++++------
+files changed, 25 insertions(+), 9 deletions(-)
+diff --git a/qapi/block-export.json b/qapi/block-export.json
+index XXXXXXX..XXXXXXX 100644
+--- a/qapi/block-export.json
++++ b/qapi/block-export.json
+@@ -XXX,XX +XXX,XX @@
+ #        SocketAddress types are supported. Passed fds must be UNIX domain
+ #        sockets.
+ # @logical-block-size: Logical block size in bytes. Defaults to 512 bytes.
++# @num-queues: Number of request virtqueues. Must be greater than 0. Defaults
++#              to 1.
+ #
+ # Since: 5.2
+ ##
+ { 'struct': 'BlockExportOptionsVhostUserBlk',
+-  'data': { 'addr': 'SocketAddress', '*logical-block-size': 'size' } }
++  'data': { 'addr': 'SocketAddress',
++        '*logical-block-size': 'size',
++            '*num-queues': 'uint16'} }
+ ##
+ # @NbdServerAddOptions:
+@@ -XXX,XX +XXX,XX @@
+ { 'union': 'BlockExportOptions',
+   'base': { 'type': 'BlockExportType',
+             'id': 'str',
+-        '*fixed-iothread': 'bool',
+-        '*iothread': 'str',
++            '*fixed-iothread': 'bool',
++            '*iothread': 'str',
+             'node-name': 'str',
+             '*writable': 'bool',
+             '*writethrough': 'bool' },
+diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
+index XXXXXXX..XXXXXXX 100644
+--- a/block/export/vhost-user-blk-server.c
++++ b/block/export/vhost-user-blk-server.c
+@@ -XXX,XX +XXX,XX @@
+ #include "util/block-helpers.h"
+ enum {
+-    VHOST_USER_BLK_MAX_QUEUES = 1,
++    VHOST_USER_BLK_NUM_QUEUES_DEFAULT = 1,
+ };
+ struct virtio_blk_inhdr {
+     unsigned char status;
+@@ -XXX,XX +XXX,XX @@ static uint64_t vu_blk_get_features(VuDev *dev)
+ull << VIRTIO_BLK_F_DISCARD |
+ull << VIRTIO_BLK_F_WRITE_ZEROES |
+ull << VIRTIO_BLK_F_CONFIG_WCE |
++               1ull << VIRTIO_BLK_F_MQ |
+ull << VIRTIO_F_VERSION_1 |
+ull << VIRTIO_RING_F_INDIRECT_DESC |
+ull << VIRTIO_RING_F_EVENT_IDX |
+@@ -XXX,XX +XXX,XX @@ static void blk_aio_detach(void *opaque)
+ static void
+ vu_blk_initialize_config(BlockDriverState *bs,
+-                           struct virtio_blk_config *config, uint32_t blk_size)
++                         struct virtio_blk_config *config,
++                         uint32_t blk_size,
++                         uint16_t num_queues)
+ {
+     config->capacity = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
+     config->blk_size = blk_size;
+@@ -XXX,XX +XXX,XX @@ vu_blk_initialize_config(BlockDriverState *bs,
+     config->seg_max = 128 - 2;
+     config->min_io_size = 1;
+     config->opt_io_size = 1;
+-    config->num_queues = VHOST_USER_BLK_MAX_QUEUES;
++    config->num_queues = num_queues;
+     config->max_discard_sectors = 32768;
+     config->max_discard_seg = 1;
+     config->discard_sector_alignment = config->blk_size >> 9;
+@@ -XXX,XX +XXX,XX @@ static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
+     BlockExportOptionsVhostUserBlk *vu_opts = &opts->u.vhost_user_blk;
+     Error *local_err = NULL;
+     uint64_t logical_block_size;
++    uint16_t num_queues = VHOST_USER_BLK_NUM_QUEUES_DEFAULT;
+     vexp->writable = opts->writable;
+     vexp->blkcfg.wce = 0;
+@@ -XXX,XX +XXX,XX @@ static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
+     }
+     vexp->blk_size = logical_block_size;
+     blk_set_guest_block_size(exp->blk, logical_block_size);
++
++    if (vu_opts->has_num_queues) {
++        num_queues = vu_opts->num_queues;
++    }
++    if (num_queues == 0) {
++        error_setg(errp, "num-queues must be greater than 0");
++        return -EINVAL;
++    }
++
+     vu_blk_initialize_config(blk_bs(exp->blk), &vexp->blkcfg,
+-                               logical_block_size);
++                             logical_block_size, num_queues);
+     blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
+                                  vexp);
+     if (!vhost_user_server_start(&vexp->vu_server, vu_opts->addr, exp->ctx,
+-                                 VHOST_USER_BLK_MAX_QUEUES, &vu_blk_iface,
+-                                 errp)) {
++                                 num_queues, &vu_blk_iface, errp)) {
+         blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
+                                         blk_aio_detach, vexp);
+         return -EADDRNOTAVAIL;
+--
+.26.2

-[Qemu-devel] [PULL 04/12] block: define .*_part io handlers in BlockDriver
+[PULL v2 24/28] block/io: fix bdrv_co_block_status_above
 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-Add handlers supporting qiov_offset parameter:
+bdrv_co_block_status_above has several design problems with handling
-    bdrv_co_preadv_part
+short backing files:
-    bdrv_co_pwritev_part
-    bdrv_co_pwritev_compressed_part
+. With want_zeros=true, it may return ret with BDRV_BLOCK_ZERO but
-This is used to reduce need of defining local_qiovs and hd_qiovs in all
+without BDRV_BLOCK_ALLOCATED flag, when actually short backing file
-corners of block layer code. The following patches will increase usage
+which produces these after-EOF zeros is inside requested backing
-of this new API part by part.
+sequence.
 . With want_zero=false, it may return pnum=0 prior to actual EOF,
 because of EOF of short backing file.
 Fix these things, making logic about short backing files clearer.
 With fixed bdrv_block_status_above we also have to improve is_zero in
 qcow2 code, otherwise iotest 154 will fail, because with this patch we
 stop to merge zeros of different types (produced by fully unallocated
 in the whole backing chain regions vs produced by short backing files).
 Note also, that this patch leaves for another day the general problem
 around block-status: misuse of BDRV_BLOCK_ALLOCATED as is-fs-allocated
 vs go-to-backing.
 Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
+Reviewed-by: Alberto Garcia <berto@igalia.com>
-Message-id: 20190604161514.262241-5-vsementsov@virtuozzo.com
+Reviewed-by: Eric Blake <eblake@redhat.com>
-Message-Id: <20190604161514.262241-5-vsementsov@virtuozzo.com>
+Message-id: 20200924194003.22080-2-vsementsov@virtuozzo.com
 [Fix s/comes/come/ as suggested by Eric Blake
 --Stefan]
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- include/block/block_int.h | 15 ++++++
+ block/io.c    | 68 ++++++++++++++++++++++++++++++++++++++++-----------
- block/backup.c            |  2 +-
+ block/qcow2.c | 16 ++++++++++--
- block/io.c                | 96 +++++++++++++++++++++++++++++++--------
+files changed, 68 insertions(+), 16 deletions(-)
  qemu-img.c                |  4 +-
 files changed, 95 insertions(+), 22 deletions(-)
-diff --git a/include/block/block_int.h b/include/block/block_int.h
-index XXXXXXX..XXXXXXX 100644
---- a/include/block/block_int.h
-+++ b/include/block/block_int.h
-@@ -XXX,XX +XXX,XX @@ struct BlockDriver {
-      */
-     int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs,
-         uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags);
-+    int coroutine_fn (*bdrv_co_preadv_part)(BlockDriverState *bs,
-+        uint64_t offset, uint64_t bytes,
-+        QEMUIOVector *qiov, size_t qiov_offset, int flags);
-     int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
-         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags);
-     /**
-@@ -XXX,XX +XXX,XX @@ struct BlockDriver {
-      */
-     int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs,
-         uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags);
-+    int coroutine_fn (*bdrv_co_pwritev_part)(BlockDriverState *bs,
-+        uint64_t offset, uint64_t bytes,
-+        QEMUIOVector *qiov, size_t qiov_offset, int flags);
-     /*
-      * Efficiently zero a region of the disk image.  Typically an image format
-@@ -XXX,XX +XXX,XX @@ struct BlockDriver {
-     int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs,
-         uint64_t offset, uint64_t bytes, QEMUIOVector *qiov);
-+    int coroutine_fn (*bdrv_co_pwritev_compressed_part)(BlockDriverState *bs,
-+        uint64_t offset, uint64_t bytes, QEMUIOVector *qiov,
-+        size_t qiov_offset);
-     int (*bdrv_snapshot_create)(BlockDriverState *bs,
-                                 QEMUSnapshotInfo *sn_info);
-@@ -XXX,XX +XXX,XX @@ struct BlockDriver {
-     const char *const *strong_runtime_opts;
- };
-+static inline bool block_driver_can_compress(BlockDriver *drv)
-+{
-+    return drv->bdrv_co_pwritev_compressed ||
-+           drv->bdrv_co_pwritev_compressed_part;
-+}
-+
- typedef struct BlockLimits {
-     /* Alignment requirement, in bytes, for offset/length of I/O
-      * requests. Must be a power of 2 less than INT_MAX; defaults to
-diff --git a/block/backup.c b/block/backup.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/backup.c
-+++ b/block/backup.c
-@@ -XXX,XX +XXX,XX @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
-         return NULL;
-     }
--    if (compress && target->drv->bdrv_co_pwritev_compressed == NULL) {
-+    if (compress && !block_driver_can_compress(target->drv)) {
-         error_setg(errp, "Compression is not supported for this drive %s",
-                    bdrv_get_device_name(target));
-         return NULL;
 diff --git a/block/io.c b/block/io.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/io.c
 +++ b/block/io.c
-@@ -XXX,XX +XXX,XX @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
+@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
+                                   int64_t *map,
-     /* Default alignment based on whether driver has byte interface */
+                                   BlockDriverState **file)
      bs->bl.request_alignment = (drv->bdrv_co_preadv ||
 -                                drv->bdrv_aio_preadv) ? 1 : 512;
 +                                drv->bdrv_aio_preadv ||
 +                                drv->bdrv_co_preadv_part) ? 1 : 512;
      /* Take some limits from the children as a default */
      if (bs->file) {
@@ -XXX,XX +XXX,XX @@ static void bdrv_co_io_em_complete(void *opaque, int ret)
  static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
                                             uint64_t offset, uint64_t bytes,
 -                                           QEMUIOVector *qiov, int flags)
 +                                           QEMUIOVector *qiov,
 +                                           size_t qiov_offset, int flags)
  {
-     BlockDriver *drv = bs->drv;
-     int64_t sector_num;
-     unsigned int nb_sectors;
-+    QEMUIOVector local_qiov;
 +    int ret;
+     BlockDriverState *p;
-     assert(!(flags & ~BDRV_REQ_MASK));
+-    int ret = 0;
-     assert(!(flags & BDRV_REQ_NO_FALLBACK));
+-    bool first = true;
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
++    int64_t eof = 0;
-         return -ENOMEDIUM;
-     }
+     assert(bs != base);
+-    for (p = bs; p != base; p = bdrv_filter_or_cow_bs(p)) {
-+    if (drv->bdrv_co_preadv_part) {
++
-+        return drv->bdrv_co_preadv_part(bs, offset, bytes, qiov, qiov_offset,
++    ret = bdrv_co_block_status(bs, want_zero, offset, bytes, pnum, map, file);
-+                                        flags);
++    if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED) {
 +        return ret;
 +    }
 +
-+    if (qiov_offset > 0 || bytes != qiov->size) {
++    if (ret & BDRV_BLOCK_EOF) {
-+        qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
++        eof = offset + *pnum;
 +        qiov = &local_qiov;
 +    }
 +
-     if (drv->bdrv_co_preadv) {
++    assert(*pnum <= bytes);
--        return drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags);
++    bytes = *pnum;
-+        ret = drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags);
++
-+        goto out;
++    for (p = bdrv_filter_or_cow_bs(bs); p != base;
-     }
++         p = bdrv_filter_or_cow_bs(p))
++    {
-     if (drv->bdrv_aio_preadv) {
+         ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
+                                    file);
-         acb = drv->bdrv_aio_preadv(bs, offset, bytes, qiov, flags,
+         if (ret < 0) {
-                                    bdrv_co_io_em_complete, &co);
+-            break;
-         if (acb == NULL) {
++            return ret;
 -            return -EIO;
 +            ret = -EIO;
 +            goto out;
          } else {
              qemu_coroutine_yield();
 -            return co.ret;
 +            ret = co.ret;
 +            goto out;
          }
-     }
+-        if (ret & BDRV_BLOCK_ZERO && ret & BDRV_BLOCK_EOF && !first) {
++        if (*pnum == 0) {
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
+             /*
-     assert(bytes <= BDRV_REQUEST_MAX_BYTES);
+-             * Reading beyond the end of the file continues to read
-     assert(drv->bdrv_co_readv);
+-             * zeroes, but we can only widen the result to the
+-             * unallocated length we learned from an earlier
--    return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
+-             * iteration.
-+    ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
++             * The top layer deferred to this layer, and because this layer is
 +             * short, any zeroes that we synthesize beyond EOF behave as if they
 +             * were allocated at this layer.
 +             *
 +             * We don't include BDRV_BLOCK_EOF into ret, as upper layer may be
 +             * larger. We'll add BDRV_BLOCK_EOF if needed at function end, see
 +             * below.
               */
 +            assert(ret & BDRV_BLOCK_EOF);
              *pnum = bytes;
 +            if (file) {
 +                *file = p;
 +            }
 +            ret = BDRV_BLOCK_ZERO | BDRV_BLOCK_ALLOCATED;
 +            break;
          }
 -        if (ret & (BDRV_BLOCK_ZERO | BDRV_BLOCK_DATA)) {
 +        if (ret & BDRV_BLOCK_ALLOCATED) {
 +            /*
 +             * We've found the node and the status, we must break.
 +             *
 +             * Drop BDRV_BLOCK_EOF, as it's not for upper layer, which may be
 +             * larger. We'll add BDRV_BLOCK_EOF if needed at function end, see
 +             * below.
 +             */
 +            ret &= ~BDRV_BLOCK_EOF;
              break;
          }
 -        /* [offset, pnum] unallocated on this layer, which could be only
 -         * the first part of [offset, bytes].  */
 -        bytes = MIN(bytes, *pnum);
 -        first = false;
 +
-+out:
++        /*
-+    if (qiov == &local_qiov) {
++         * OK, [offset, offset + *pnum) region is unallocated on this layer,
-+        qemu_iovec_destroy(&local_qiov);
++         * let's continue the diving.
 +         */
 +        assert(*pnum <= bytes);
 +        bytes = *pnum;
 +    }
 +
-+    return ret;
++    if (offset + *pnum == eof) {
- }
++        ret |= BDRV_BLOCK_EOF;
  static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
                                              uint64_t offset, uint64_t bytes,
 -                                            QEMUIOVector *qiov, int flags)
 +                                            QEMUIOVector *qiov,
 +                                            size_t qiov_offset, int flags)
  {
      BlockDriver *drv = bs->drv;
      int64_t sector_num;
      unsigned int nb_sectors;
 +    QEMUIOVector local_qiov;
      int ret;
      assert(!(flags & ~BDRV_REQ_MASK));
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
          return -ENOMEDIUM;
      }
-+    if (drv->bdrv_co_pwritev_part) {
-+        ret = drv->bdrv_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset,
-+                                        flags & bs->supported_write_flags);
-+        flags &= ~bs->supported_write_flags;
-+        goto emulate_flags;
-+    }
-+
-+    if (qiov_offset > 0 || bytes != qiov->size) {
-+        qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
-+        qiov = &local_qiov;
-+    }
-+
-     if (drv->bdrv_co_pwritev) {
-         ret = drv->bdrv_co_pwritev(bs, offset, bytes, qiov,
-                                    flags & bs->supported_write_flags);
-@@ -XXX,XX +XXX,XX @@ emulate_flags:
-         ret = bdrv_co_flush(bs);
-     }
-+    if (qiov == &local_qiov) {
-+        qemu_iovec_destroy(&local_qiov);
-+    }
 +
      return ret;
  }
- static int coroutine_fn
+diff --git a/block/qcow2.c b/block/qcow2.c
- bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
+index XXXXXXX..XXXXXXX 100644
--                               uint64_t bytes, QEMUIOVector *qiov)
+--- a/block/qcow2.c
-+                               uint64_t bytes, QEMUIOVector *qiov,
++++ b/block/qcow2.c
-+                               size_t qiov_offset)
+@@ -XXX,XX +XXX,XX @@ static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)
- {
+     if (!bytes) {
-     BlockDriver *drv = bs->drv;
+         return true;
 +    QEMUIOVector local_qiov;
 +    int ret;
      if (!drv) {
          return -ENOMEDIUM;
      }
+-    res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL);
--    if (!drv->bdrv_co_pwritev_compressed) {
+-    return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes;
 +    if (!block_driver_can_compress(drv)) {
          return -ENOTSUP;
      }
 -    return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov);
 +    if (drv->bdrv_co_pwritev_compressed_part) {
 +        return drv->bdrv_co_pwritev_compressed_part(bs, offset, bytes,
 +                                                    qiov, qiov_offset);
 +    }
 +
-+    if (qiov_offset == 0) {
++    /*
-+        return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov);
++     * bdrv_block_status_above doesn't merge different types of zeros, for
-+    }
++     * example, zeros which come from the region which is unallocated in
 +     * the whole backing chain, and zeros which come because of a short
 +     * backing file. So, we need a loop.
 +     */
 +    do {
 +        res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL);
 +        offset += nr;
 +        bytes -= nr;
 +    } while (res >= 0 && (res & BDRV_BLOCK_ZERO) && nr && bytes);
 +
-+    qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
++    return res >= 0 && (res & BDRV_BLOCK_ZERO) && bytes == 0;
 +    ret = drv->bdrv_co_pwritev_compressed(bs, offset, bytes, &local_qiov);
 +    qemu_iovec_destroy(&local_qiov);
 +
 +    return ret;
  }
- static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
+ static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
              qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);
              ret = bdrv_driver_preadv(bs, cluster_offset, pnum,
 -                                     &local_qiov, 0);
 +                                     &local_qiov, 0, 0);
              if (ret < 0) {
                  goto err;
              }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
                   * necessary to flush even in cache=writethrough mode.
                   */
                  ret = bdrv_driver_pwritev(bs, cluster_offset, pnum,
 -                                          &local_qiov,
 +                                          &local_qiov, 0,
                                            BDRV_REQ_WRITE_UNCHANGED);
              }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
              qemu_iovec_init(&local_qiov, qiov->niov);
              qemu_iovec_concat(&local_qiov, qiov, progress, pnum - skip_bytes);
              ret = bdrv_driver_preadv(bs, offset + progress, local_qiov.size,
 -                                     &local_qiov, 0);
 +                                     &local_qiov, 0, 0);
              qemu_iovec_destroy(&local_qiov);
              if (ret < 0) {
                  goto err;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
      max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
      if (bytes <= max_bytes && bytes <= max_transfer) {
 -        ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0);
 +        ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0, 0);
          goto out;
      }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
              qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
              ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining,
 -                                     num, &local_qiov, 0);
 +                                     num, &local_qiov, 0, 0);
              max_bytes -= num;
              qemu_iovec_destroy(&local_qiov);
          } else {
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
              }
              qemu_iovec_init_buf(&qiov, buf, num);
 -            ret = bdrv_driver_pwritev(bs, offset, num, &qiov, write_flags);
 +            ret = bdrv_driver_pwritev(bs, offset, num, &qiov, 0, write_flags);
              /* Keep bounce buffer around if it is big enough for all
               * all future requests.
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
          bdrv_debug_event(bs, BLKDBG_PWRITEV_ZERO);
          ret = bdrv_co_do_pwrite_zeroes(bs, offset, bytes, flags);
      } else if (flags & BDRV_REQ_WRITE_COMPRESSED) {
 -        ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, qiov);
 +        ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, qiov, 0);
      } else if (bytes <= max_transfer) {
          bdrv_debug_event(bs, BLKDBG_PWRITEV);
 -        ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, flags);
 +        ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, 0, flags);
      } else {
          bdrv_debug_event(bs, BLKDBG_PWRITEV);
          while (bytes_remaining) {
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
              qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
              ret = bdrv_driver_pwritev(bs, offset + bytes - bytes_remaining,
 -                                      num, &local_qiov, local_flags);
 +                                      num, &local_qiov, 0, local_flags);
              qemu_iovec_destroy(&local_qiov);
              if (ret < 0) {
                  break;
 diff --git a/qemu-img.c b/qemu-img.c
 index XXXXXXX..XXXXXXX 100644
 --- a/qemu-img.c
 +++ b/qemu-img.c
@@ -XXX,XX +XXX,XX @@ static int img_convert(int argc, char **argv)
          const char *preallocation =
              qemu_opt_get(opts, BLOCK_OPT_PREALLOC);
 -        if (drv && !drv->bdrv_co_pwritev_compressed) {
 +        if (drv && !block_driver_can_compress(drv)) {
              error_report("Compression not supported for this file format");
              ret = -1;
              goto out;
@@ -XXX,XX +XXX,XX @@ static int img_convert(int argc, char **argv)
      }
      out_bs = blk_bs(s.target);
 -    if (s.compressed && !out_bs->drv->bdrv_co_pwritev_compressed) {
 +    if (s.compressed && !block_driver_can_compress(out_bs->drv)) {
          error_report("Compression not supported for this file format");
          ret = -1;
          goto out;
 --
-.21.0
+.26.2

-[Qemu-devel] [PULL 05/12] block/io: bdrv_co_do_copy_on_readv: use and support qiov_offset
+[PULL v2 25/28] block/io: bdrv_common_block_status_above: support include_base
 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-Use and support new API in bdrv_co_do_copy_on_readv. Note that in case
+In order to reuse bdrv_common_block_status_above in
-of allocated-in-top we need to shrink read size to MIN(..) by hand, as
+bdrv_is_allocated_above, let's support include_base parameter.
 pre-patch this was actually done implicitly by qemu_iovec_concat (and
 we used local_qiov.size).
 Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
+Reviewed-by: Alberto Garcia <berto@igalia.com>
-Message-id: 20190604161514.262241-6-vsementsov@virtuozzo.com
+Reviewed-by: Eric Blake <eblake@redhat.com>
-Message-Id: <20190604161514.262241-6-vsementsov@virtuozzo.com>
+Message-id: 20200924194003.22080-3-vsementsov@virtuozzo.com
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- block/io.c | 18 +++++++++---------
+ block/coroutines.h |  2 ++
-file changed, 9 insertions(+), 9 deletions(-)
+ block/io.c         | 21 ++++++++++++++-------
 files changed, 16 insertions(+), 7 deletions(-)
+diff --git a/block/coroutines.h b/block/coroutines.h
+index XXXXXXX..XXXXXXX 100644
+--- a/block/coroutines.h
++++ b/block/coroutines.h
+@@ -XXX,XX +XXX,XX @@ bdrv_pwritev(BdrvChild *child, int64_t offset, unsigned int bytes,
+ int coroutine_fn
+ bdrv_co_common_block_status_above(BlockDriverState *bs,
+                                   BlockDriverState *base,
++                                  bool include_base,
+                                   bool want_zero,
+                                   int64_t offset,
+                                   int64_t bytes,
+@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
+ int generated_co_wrapper
+ bdrv_common_block_status_above(BlockDriverState *bs,
+                                BlockDriverState *base,
++                               bool include_base,
+                                bool want_zero,
+                                int64_t offset,
+                                int64_t bytes,
 diff --git a/block/io.c b/block/io.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/io.c
 +++ b/block/io.c
-@@ -XXX,XX +XXX,XX @@ bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
+@@ -XXX,XX +XXX,XX @@ early_out:
+ int coroutine_fn
- static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
+ bdrv_co_common_block_status_above(BlockDriverState *bs,
-         int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+                                   BlockDriverState *base,
--        int flags)
++                                  bool include_base,
-+        size_t qiov_offset, int flags)
+                                   bool want_zero,
                                    int64_t offset,
                                    int64_t bytes,
@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
      BlockDriverState *p;
      int64_t eof = 0;
 -    assert(bs != base);
 +    assert(include_base || bs != base);
 +    assert(!include_base || base); /* Can't include NULL base */
      ret = bdrv_co_block_status(bs, want_zero, offset, bytes, pnum, map, file);
 -    if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED) {
 +    if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED || bs == base) {
          return ret;
      }
@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
      assert(*pnum <= bytes);
      bytes = *pnum;
 -    for (p = bdrv_filter_or_cow_bs(bs); p != base;
 +    for (p = bdrv_filter_or_cow_bs(bs); include_base || p != base;
           p = bdrv_filter_or_cow_bs(p))
      {
          ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
              break;
          }
 +        if (p == base) {
 +            assert(include_base);
 +            break;
 +        }
 +
          /*
           * OK, [offset, offset + *pnum) region is unallocated on this layer,
           * let's continue the diving.
@@ -XXX,XX +XXX,XX @@ int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
                              int64_t offset, int64_t bytes, int64_t *pnum,
                              int64_t *map, BlockDriverState **file)
  {
-     BlockDriverState *bs = child->bs;
+-    return bdrv_common_block_status_above(bs, base, true, offset, bytes,
++    return bdrv_common_block_status_above(bs, base, false, true, offset, bytes,
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
+                                           pnum, map, file);
-     void *bounce_buffer;
+ }
-     BlockDriver *drv = bs->drv;
+@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
--    QEMUIOVector local_qiov;
+     int ret;
-     int64_t cluster_offset;
+     int64_t dummy;
-     int64_t cluster_bytes;
-     size_t skip_bytes;
+-    ret = bdrv_common_block_status_above(bs, bdrv_filter_or_cow_bs(bs), false,
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
+-                                         offset, bytes, pnum ? pnum : &dummy,
-         assert(skip_bytes < pnum);
+-                                         NULL, NULL);
++    ret = bdrv_common_block_status_above(bs, bs, true, false, offset,
-         if (ret <= 0) {
++                                         bytes, pnum ? pnum : &dummy, NULL,
-+            QEMUIOVector local_qiov;
++                                         NULL);
-+
+     if (ret < 0) {
-             /* Must copy-on-read; use the bounce buffer */
+         return ret;
-             pnum = MIN(pnum, MAX_BOUNCE_BUFFER);
+     }
              qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
              }
              if (!(flags & BDRV_REQ_PREFETCH)) {
 -                qemu_iovec_from_buf(qiov, progress, bounce_buffer + skip_bytes,
 +                qemu_iovec_from_buf(qiov, qiov_offset + progress,
 +                                    bounce_buffer + skip_bytes,
                                      pnum - skip_bytes);
              }
          } else if (!(flags & BDRV_REQ_PREFETCH)) {
              /* Read directly into the destination */
 -            qemu_iovec_init(&local_qiov, qiov->niov);
 -            qemu_iovec_concat(&local_qiov, qiov, progress, pnum - skip_bytes);
 -            ret = bdrv_driver_preadv(bs, offset + progress, local_qiov.size,
 -                                     &local_qiov, 0, 0);
 -            qemu_iovec_destroy(&local_qiov);
 +            ret = bdrv_driver_preadv(bs, offset + progress,
 +                                     MIN(pnum - skip_bytes, bytes - progress),
 +                                     qiov, qiov_offset + progress, 0);
              if (ret < 0) {
                  goto err;
              }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
          }
          if (!ret || pnum != bytes) {
 -            ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, flags);
 +            ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, 0, flags);
              goto out;
          } else if (flags & BDRV_REQ_PREFETCH) {
              goto out;
 --
-.21.0
+.26.2

-[Qemu-devel] [PULL 06/12] block/io: bdrv_co_do_copy_on_readv: lazy allocation
+[PULL v2 26/28] block/io: bdrv_common_block_status_above: support bs == base
 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-Allocate bounce_buffer only if it is really needed. Also, sub-optimize
+We are going to reuse bdrv_common_block_status_above in
-allocation size (why not?).
+bdrv_is_allocated_above. bdrv_is_allocated_above may be called with
 include_base == false and still bs == base (for ex. from img_rebase()).
 So, support this corner case.
 Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
+Reviewed-by: Kevin Wolf <kwolf@redhat.com>
-Message-id: 20190604161514.262241-7-vsementsov@virtuozzo.com
+Reviewed-by: Eric Blake <eblake@redhat.com>
-Message-Id: <20190604161514.262241-7-vsementsov@virtuozzo.com>
+Reviewed-by: Alberto Garcia <berto@igalia.com>
 Message-id: 20200924194003.22080-4-vsementsov@virtuozzo.com
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- block/io.c | 21 ++++++++++++---------
+ block/io.c | 6 +++++-
-file changed, 12 insertions(+), 9 deletions(-)
+file changed, 5 insertions(+), 1 deletion(-)
 diff --git a/block/io.c b/block/io.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/io.c
 +++ b/block/io.c
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
+@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
-      * modifying the image file.  This is critical for zero-copy guest I/O
+     BlockDriverState *p;
-      * where anything might happen inside guest memory.
+     int64_t eof = 0;
-      */
--    void *bounce_buffer;
+-    assert(include_base || bs != base);
-+    void *bounce_buffer = NULL;
+     assert(!include_base || base); /* Can't include NULL base */
-     BlockDriver *drv = bs->drv;
++    if (!include_base && bs == base) {
-     int64_t cluster_offset;
++        *pnum = bytes;
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
++        return 0;
-     trace_bdrv_co_do_copy_on_readv(bs, offset, bytes,
++    }
                                     cluster_offset, cluster_bytes);
 -    bounce_buffer = qemu_try_blockalign(bs,
 -                                        MIN(MIN(max_transfer, cluster_bytes),
 -                                            MAX_BOUNCE_BUFFER));
 -    if (bounce_buffer == NULL) {
 -        ret = -ENOMEM;
 -        goto err;
 -    }
 -
      while (cluster_bytes) {
          int64_t pnum;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
              /* Must copy-on-read; use the bounce buffer */
              pnum = MIN(pnum, MAX_BOUNCE_BUFFER);
 +            if (!bounce_buffer) {
 +                int64_t max_we_need = MAX(pnum, cluster_bytes - pnum);
 +                int64_t max_allowed = MIN(max_transfer, MAX_BOUNCE_BUFFER);
 +                int64_t bounce_buffer_len = MIN(max_we_need, max_allowed);
 +
-+                bounce_buffer = qemu_try_blockalign(bs, bounce_buffer_len);
+     ret = bdrv_co_block_status(bs, want_zero, offset, bytes, pnum, map, file);
-+                if (!bounce_buffer) {
+     if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED || bs == base) {
-+                    ret = -ENOMEM;
+         return ret;
 +                    goto err;
 +                }
 +            }
              qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);
              ret = bdrv_driver_preadv(bs, cluster_offset, pnum,
 --
-.21.0
+.26.2

-[Qemu-devel] [PULL 07/12] block/io: bdrv_aligned_preadv: use and support qiov_offset
+[PULL v2 27/28] block/io: fix bdrv_is_allocated_above
 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-Use and support new API in bdrv_co_do_copy_on_readv.
+bdrv_is_allocated_above wrongly handles short backing files: it reports
 after-EOF space as UNALLOCATED which is wrong, as on read the data is
 generated on the level of short backing file (if all overlays have
 unallocated areas at that place).
 Reusing bdrv_common_block_status_above fixes the issue and unifies code
 path.
 Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
+Reviewed-by: Eric Blake <eblake@redhat.com>
-Message-id: 20190604161514.262241-8-vsementsov@virtuozzo.com
+Reviewed-by: Alberto Garcia <berto@igalia.com>
-Message-Id: <20190604161514.262241-8-vsementsov@virtuozzo.com>
+Message-id: 20200924194003.22080-5-vsementsov@virtuozzo.com
 [Fix s/has/have/ as suggested by Eric Blake. Fix s/area/areas/.
 --Stefan]
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- block/io.c | 21 ++++++++-------------
+ block/io.c | 43 +++++--------------------------------------
-file changed, 8 insertions(+), 13 deletions(-)
+file changed, 5 insertions(+), 38 deletions(-)
 diff --git a/block/io.c b/block/io.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/io.c
 +++ b/block/io.c
-@@ -XXX,XX +XXX,XX @@ err:
+@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
   * at 'offset + *pnum' may return the same allocation status (in other
   * words, the result is not necessarily the maximum possible range);
   * but 'pnum' will only be 0 when end of file is reached.
 - *
   */
- static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
+ int bdrv_is_allocated_above(BlockDriverState *top,
-     BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
+                             BlockDriverState *base,
--    int64_t align, QEMUIOVector *qiov, int flags)
+                             bool include_base, int64_t offset,
-+    int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
+                             int64_t bytes, int64_t *pnum)
  {
-     BlockDriverState *bs = child->bs;
+-    BlockDriverState *intermediate;
-     int64_t total_bytes, max_bytes;
+-    int ret;
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
+-    int64_t n = bytes;
-     assert(is_power_of_2(align));
+-
-     assert((offset & (align - 1)) == 0);
+-    assert(base || !include_base);
-     assert((bytes & (align - 1)) == 0);
+-
--    assert(!qiov || bytes == qiov->size);
+-    intermediate = top;
-     assert((bs->open_flags & BDRV_O_NO_IO) == 0);
+-    while (include_base || intermediate != base) {
-     max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX),
+-        int64_t pnum_inter;
-                                    align);
+-        int64_t size_inter;
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
+-
-         }
+-        assert(intermediate);
+-        ret = bdrv_is_allocated(intermediate, offset, bytes, &pnum_inter);
-         if (!ret || pnum != bytes) {
+-        if (ret < 0) {
--            ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, 0, flags);
+-            return ret;
-+            ret = bdrv_co_do_copy_on_readv(child, offset, bytes,
+-        }
-+                                           qiov, qiov_offset, flags);
+-        if (ret) {
-             goto out;
+-            *pnum = pnum_inter;
-         } else if (flags & BDRV_REQ_PREFETCH) {
+-            return 1;
-             goto out;
+-        }
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
+-
+-        size_inter = bdrv_getlength(intermediate);
-     max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
+-        if (size_inter < 0) {
-     if (bytes <= max_bytes && bytes <= max_transfer) {
+-            return size_inter;
--        ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0, 0);
+-        }
-+        ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, 0);
+-        if (n > pnum_inter &&
-         goto out;
+-            (intermediate == top || offset + pnum_inter < size_inter)) {
 -            n = pnum_inter;
 -        }
 -
 -        if (intermediate == base) {
 -            break;
 -        }
 -
 -        intermediate = bdrv_filter_or_cow_bs(intermediate);
 +    int ret = bdrv_common_block_status_above(top, base, include_base, false,
 +                                             offset, bytes, pnum, NULL, NULL);
 +    if (ret < 0) {
 +        return ret;
      }
-@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
+-    *pnum = n;
-         int num;
+-    return 0;
++    return !!(ret & BDRV_BLOCK_ALLOCATED);
-         if (max_bytes) {
+ }
--            QEMUIOVector local_qiov;
--
+ int coroutine_fn
              num = MIN(bytes_remaining, MIN(max_bytes, max_transfer));
              assert(num);
 -            qemu_iovec_init(&local_qiov, qiov->niov);
 -            qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
              ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining,
 -                                     num, &local_qiov, 0, 0);
 +                                     num, qiov, bytes - bytes_remaining, 0);
              max_bytes -= num;
 -            qemu_iovec_destroy(&local_qiov);
          } else {
              num = bytes_remaining;
              ret = qemu_iovec_memset(qiov, bytes - bytes_remaining, 0,
@@ -XXX,XX +XXX,XX @@ static int bdrv_padding_rmw_read(BdrvChild *child,
              bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
          }
          ret = bdrv_aligned_preadv(child, req, req->overlap_offset, bytes,
 -                                  align, &local_qiov, 0);
 +                                  align, &local_qiov, 0, 0);
          if (ret < 0) {
              return ret;
          }
@@ -XXX,XX +XXX,XX @@ static int bdrv_padding_rmw_read(BdrvChild *child,
          ret = bdrv_aligned_preadv(
                  child, req,
                  req->overlap_offset + req->overlap_bytes - align,
 -                align, align, &local_qiov, 0);
 +                align, align, &local_qiov, 0, 0);
          if (ret < 0) {
              return ret;
          }
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child,
      tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_READ);
      ret = bdrv_aligned_preadv(child, &req, offset, bytes,
                                bs->bl.request_alignment,
 -                              qiov, flags);
 +                              qiov, 0, flags);
      tracked_request_end(&req);
      bdrv_dec_in_flight(bs);
 --
-.21.0
+.26.2

-[Qemu-devel] [PULL 10/12] block/qcow2: refactor qcow2_co_preadv to use buffer-based io
+[PULL v2 28/28] iotests: add commit top->base cases to 274
 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-Use buffer based io in encrypted case.
+These cases are fixed by previous patches around block_status and
 is_allocated.
 Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
+Reviewed-by: Eric Blake <eblake@redhat.com>
-Message-id: 20190604161514.262241-11-vsementsov@virtuozzo.com
+Reviewed-by: Alberto Garcia <berto@igalia.com>
-Message-Id: <20190604161514.262241-11-vsementsov@virtuozzo.com>
+Message-id: 20200924194003.22080-6-vsementsov@virtuozzo.com
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- block/qcow2.c | 28 ++++++++++++++++------------
+ tests/qemu-iotests/274     | 20 +++++++++++
-file changed, 16 insertions(+), 12 deletions(-)
+ tests/qemu-iotests/274.out | 68 ++++++++++++++++++++++++++++++++++++++
 files changed, 88 insertions(+)
-diff --git a/block/qcow2.c b/block/qcow2.c
+diff --git a/tests/qemu-iotests/274 b/tests/qemu-iotests/274
 index XXXXXXX..XXXXXXX 100755
 --- a/tests/qemu-iotests/274
 +++ b/tests/qemu-iotests/274
@@ -XXX,XX +XXX,XX @@ with iotests.FilePath('base') as base, \
      iotests.qemu_io_log('-c', 'read -P 1 0 %d' % size_short, mid)
      iotests.qemu_io_log('-c', 'read -P 0 %d %d' % (size_short, size_diff), mid)
 +    iotests.log('=== Testing qemu-img commit (top -> base) ===')
 +
 +    create_chain()
 +    iotests.qemu_img_log('commit', '-b', base, top)
 +    iotests.img_info_log(base)
 +    iotests.qemu_io_log('-c', 'read -P 1 0 %d' % size_short, base)
 +    iotests.qemu_io_log('-c', 'read -P 0 %d %d' % (size_short, size_diff), base)
 +
 +    iotests.log('=== Testing QMP active commit (top -> base) ===')
 +
 +    create_chain()
 +    with create_vm() as vm:
 +        vm.launch()
 +        vm.qmp_log('block-commit', device='top', base_node='base',
 +                   job_id='job0', auto_dismiss=False)
 +        vm.run_job('job0', wait=5)
 +
 +    iotests.img_info_log(mid)
 +    iotests.qemu_io_log('-c', 'read -P 1 0 %d' % size_short, base)
 +    iotests.qemu_io_log('-c', 'read -P 0 %d %d' % (size_short, size_diff), base)
      iotests.log('== Resize tests ==')
 diff --git a/tests/qemu-iotests/274.out b/tests/qemu-iotests/274.out
 index XXXXXXX..XXXXXXX 100644
---- a/block/qcow2.c
+--- a/tests/qemu-iotests/274.out
-+++ b/block/qcow2.c
++++ b/tests/qemu-iotests/274.out
-@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
+@@ -XXX,XX +XXX,XX @@ read 1048576/1048576 bytes at offset 0
-                 }
+ read 1048576/1048576 bytes at offset 1048576
+MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-                 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
--                qemu_iovec_reset(&hd_qiov);
++=== Testing qemu-img commit (top -> base) ===
--                qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
++Formatting 'TEST_DIR/PID-base', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 lazy_refcounts=off refcount_bits=16
 -            }
 -            BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
 -            ret = bdrv_co_preadv(s->data_file,
 -                                 cluster_offset + offset_in_cluster,
 -                                 cur_bytes, &hd_qiov, 0);
 -            if (ret < 0) {
 -                goto fail;
 -            }
 -            if (bs->encrypted) {
 -                assert(s->crypto);
 +                BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
 +                ret = bdrv_co_pread(s->data_file,
 +                                    cluster_offset + offset_in_cluster,
 +                                    cur_bytes, cluster_data, 0);
 +                if (ret < 0) {
 +                    goto fail;
 +                }
 +
-                 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
++Formatting 'TEST_DIR/PID-mid', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=1048576 backing_file=TEST_DIR/PID-base backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
-                 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
++
-                 if (qcow2_co_decrypt(bs, cluster_offset, offset,
++Formatting 'TEST_DIR/PID-top', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 backing_file=TEST_DIR/PID-mid backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
-@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
++
-                     goto fail;
++wrote 2097152/2097152 bytes at offset 0
-                 }
++2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-                 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes);
++
-+            } else {
++Image committed.
-+                BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
++
-+                ret = bdrv_co_preadv(s->data_file,
++image: TEST_IMG
-+                                     cluster_offset + offset_in_cluster,
++file format: IMGFMT
-+                                     cur_bytes, &hd_qiov, 0);
++virtual size: 2 MiB (2097152 bytes)
-+                if (ret < 0) {
++cluster_size: 65536
-+                    goto fail;
++Format specific information:
-+                }
++    compat: 1.1
-             }
++    compression type: zlib
-             break;
++    lazy refcounts: false
++    refcount bits: 16
 +    corrupt: false
 +    extended l2: false
 +
 +read 1048576/1048576 bytes at offset 0
 +1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 +
 +read 1048576/1048576 bytes at offset 1048576
 +1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 +
 +=== Testing QMP active commit (top -> base) ===
 +Formatting 'TEST_DIR/PID-base', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 lazy_refcounts=off refcount_bits=16
 +
 +Formatting 'TEST_DIR/PID-mid', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=1048576 backing_file=TEST_DIR/PID-base backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
 +
 +Formatting 'TEST_DIR/PID-top', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 backing_file=TEST_DIR/PID-mid backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
 +
 +wrote 2097152/2097152 bytes at offset 0
 +2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 +
 +{"execute": "block-commit", "arguments": {"auto-dismiss": false, "base-node": "base", "device": "top", "job-id": "job0"}}
 +{"return": {}}
 +{"execute": "job-complete", "arguments": {"id": "job0"}}
 +{"return": {}}
 +{"data": {"device": "job0", "len": 1048576, "offset": 1048576, "speed": 0, "type": "commit"}, "event": "BLOCK_JOB_READY", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 +{"data": {"device": "job0", "len": 1048576, "offset": 1048576, "speed": 0, "type": "commit"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 +{"execute": "job-dismiss", "arguments": {"id": "job0"}}
 +{"return": {}}
 +image: TEST_IMG
 +file format: IMGFMT
 +virtual size: 1 MiB (1048576 bytes)
 +cluster_size: 65536
 +backing file: TEST_DIR/PID-base
 +backing file format: IMGFMT
 +Format specific information:
 +    compat: 1.1
 +    compression type: zlib
 +    lazy refcounts: false
 +    refcount bits: 16
 +    corrupt: false
 +    extended l2: false
 +
 +read 1048576/1048576 bytes at offset 0
 +1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 +
 +read 1048576/1048576 bytes at offset 1048576
 +1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 +
  == Resize tests ==
  === preallocation=off ===
  Formatting 'TEST_DIR/PID-base', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=6442450944 lazy_refcounts=off refcount_bits=16
 --
-.21.0
+.26.2

The following changes since commit dac03af5d5482ec7ee9c23db467bb7230b33c0d9:

Merge remote-tracking branch 'remotes/rth/tags/pull-axp-20190825' into staging (2019-08-27 10:00:51 +0100)

are available in the Git repository at:

https://github.com/stefanha/qemu.git tags/block-pull-request

for you to fetch changes up to 5396234b96a2ac743f48644529771498e036e698:

block/qcow2: implement .bdrv_co_pwritev(_compressed)_part (2019-08-27 14:58:42 +0100)

----------------------------------------------------------------
Pull request

----------------------------------------------------------------

Vladimir Sementsov-Ogievskiy (12):
  util/iov: introduce qemu_iovec_init_extended
  util/iov: improve qemu_iovec_is_zero
  block/io: refactor padding
  block: define .*_part io handlers in BlockDriver
  block/io: bdrv_co_do_copy_on_readv: use and support qiov_offset
  block/io: bdrv_co_do_copy_on_readv: lazy allocation
  block/io: bdrv_aligned_preadv: use and support qiov_offset
  block/io: bdrv_aligned_pwritev: use and support qiov_offset
  block/io: introduce bdrv_co_p{read, write}v_part
  block/qcow2: refactor qcow2_co_preadv to use buffer-based io
  block/qcow2: implement .bdrv_co_preadv_part
  block/qcow2: implement .bdrv_co_pwritev(_compressed)_part

-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Introduce new initialization API, to create requests with padding. Will
be used in the following patch. New API uses qemu_iovec_init_buf if
resulting io vector has only one element, to avoid extra allocations.
So, we need to update qemu_iovec_destroy to support destroying such
QIOVs.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-2-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-2-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/qemu/iov.h |   7 +++
 util/iov.c         | 112 +++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 114 insertions(+), 5 deletions(-)

diff --git a/include/qemu/iov.h b/include/qemu/iov.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/iov.h
+++ b/include/qemu/iov.h
@@ -XXX,XX +XXX,XX @@ static inline void *qemu_iovec_buf(QEMUIOVector *qiov)
 
 void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint);
 void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov);
+void qemu_iovec_init_extended(
+        QEMUIOVector *qiov,
+        void *head_buf, size_t head_len,
+        QEMUIOVector *mid_qiov, size_t mid_offset, size_t mid_len,
+        void *tail_buf, size_t tail_len);
+void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source,
+                           size_t offset, size_t len);
 void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len);
 void qemu_iovec_concat(QEMUIOVector *dst,
                        QEMUIOVector *src, size_t soffset, size_t sbytes);
diff --git a/util/iov.c b/util/iov.c
index XXXXXXX..XXXXXXX 100644
--- a/util/iov.c
+++ b/util/iov.c
@@ -XXX,XX +XXX,XX @@ void qemu_iovec_concat(QEMUIOVector *dst,
     qemu_iovec_concat_iov(dst, src->iov, src->niov, soffset, sbytes);
 }
 
+/*
+ * qiov_find_iov
+ *
+ * Return pointer to iovec structure, where byte at @offset in original vector
+ * @iov exactly is.
+ * Set @remaining_offset to be offset inside that iovec to the same byte.
+ */
+static struct iovec *iov_skip_offset(struct iovec *iov, size_t offset,
+                                     size_t *remaining_offset)
+{
+    while (offset > 0 && offset >= iov->iov_len) {
+        offset -= iov->iov_len;
+        iov++;
+    }
+    *remaining_offset = offset;
+
+    return iov;
+}
+
+/*
+ * qiov_slice
+ *
+ * Find subarray of iovec's, containing requested range. @head would
+ * be offset in first iov (returned by the function), @tail would be
+ * count of extra bytes in last iovec (returned iov + @niov - 1).
+ */
+static struct iovec *qiov_slice(QEMUIOVector *qiov,
+                                size_t offset, size_t len,
+                                size_t *head, size_t *tail, int *niov)
+{
+    struct iovec *iov, *end_iov;
+
+    assert(offset + len <= qiov->size);
+
+    iov = iov_skip_offset(qiov->iov, offset, head);
+    end_iov = iov_skip_offset(iov, *head + len, tail);
+
+    if (*tail > 0) {
+        assert(*tail < end_iov->iov_len);
+        *tail = end_iov->iov_len - *tail;
+        end_iov++;
+    }
+
+    *niov = end_iov - iov;
+
+    return iov;
+}
+
+/*
+ * Compile new iovec, combining @head_buf buffer, sub-qiov of @mid_qiov,
+ * and @tail_buf buffer into new qiov.
+ */
+void qemu_iovec_init_extended(
+        QEMUIOVector *qiov,
+        void *head_buf, size_t head_len,
+        QEMUIOVector *mid_qiov, size_t mid_offset, size_t mid_len,
+        void *tail_buf, size_t tail_len)
+{
+    size_t mid_head, mid_tail;
+    int total_niov, mid_niov = 0;
+    struct iovec *p, *mid_iov;
+
+    if (mid_len) {
+        mid_iov = qiov_slice(mid_qiov, mid_offset, mid_len,
+                             &mid_head, &mid_tail, &mid_niov);
+    }
+
+    total_niov = !!head_len + mid_niov + !!tail_len;
+    if (total_niov == 1) {
+        qemu_iovec_init_buf(qiov, NULL, 0);
+        p = &qiov->local_iov;
+    } else {
+        qiov->niov = qiov->nalloc = total_niov;
+        qiov->size = head_len + mid_len + tail_len;
+        p = qiov->iov = g_new(struct iovec, qiov->niov);
+    }
+
+    if (head_len) {
+        p->iov_base = head_buf;
+        p->iov_len = head_len;
+        p++;
+    }
+
+    if (mid_len) {
+        memcpy(p, mid_iov, mid_niov * sizeof(*p));
+        p[0].iov_base = (uint8_t *)p[0].iov_base + mid_head;
+        p[0].iov_len -= mid_head;
+        p[mid_niov - 1].iov_len -= mid_tail;
+        p += mid_niov;
+    }
+
+    if (tail_len) {
+        p->iov_base = tail_buf;
+        p->iov_len = tail_len;
+    }
+}
+
 /*
  * Check if the contents of the iovecs are all zero
  */
@@ -XXX,XX +XXX,XX @@ bool qemu_iovec_is_zero(QEMUIOVector *qiov)
     return true;
 }
 
+void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source,
+                           size_t offset, size_t len)
+{
+    qemu_iovec_init_extended(qiov, NULL, 0, source, offset, len, NULL, 0);
+}
+
 void qemu_iovec_destroy(QEMUIOVector *qiov)
 {
-    assert(qiov->nalloc != -1);
+    if (qiov->nalloc != -1) {
+        g_free(qiov->iov);
+    }
 
-    qemu_iovec_reset(qiov);
-    g_free(qiov->iov);
-    qiov->nalloc = 0;
-    qiov->iov = NULL;
+    memset(qiov, 0, sizeof(*qiov));
 }
 
 void qemu_iovec_reset(QEMUIOVector *qiov)
-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

We'll need to check a part of qiov soon, so implement it now.

Optimization with align down to 4 * sizeof(long) is dropped due to:
1. It is strange: it aligns length of the buffer, but where is a
   guarantee that buffer pointer is aligned itself?
2. buffer_is_zero() is a better place for optimizations and it has
   them.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-3-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-3-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/qemu/iov.h |  2 +-
 block/io.c         |  2 +-
 util/iov.c         | 31 +++++++++++++++++++------------
 3 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/include/qemu/iov.h b/include/qemu/iov.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/iov.h
+++ b/include/qemu/iov.h
@@ -XXX,XX +XXX,XX @@ void qemu_iovec_concat(QEMUIOVector *dst,
 size_t qemu_iovec_concat_iov(QEMUIOVector *dst,
                              struct iovec *src_iov, unsigned int src_cnt,
                              size_t soffset, size_t sbytes);
-bool qemu_iovec_is_zero(QEMUIOVector *qiov);
+bool qemu_iovec_is_zero(QEMUIOVector *qiov, size_t qiov_offeset, size_t bytes);
 void qemu_iovec_destroy(QEMUIOVector *qiov);
 void qemu_iovec_reset(QEMUIOVector *qiov);
 size_t qemu_iovec_to_buf(QEMUIOVector *qiov, size_t offset,
diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
 
     if (!ret && bs->detect_zeroes != BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF &&
         !(flags & BDRV_REQ_ZERO_WRITE) && drv->bdrv_co_pwrite_zeroes &&
-        qemu_iovec_is_zero(qiov)) {
+        qemu_iovec_is_zero(qiov, 0, qiov->size)) {
         flags |= BDRV_REQ_ZERO_WRITE;
         if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) {
             flags |= BDRV_REQ_MAY_UNMAP;
diff --git a/util/iov.c b/util/iov.c
index XXXXXXX..XXXXXXX 100644
--- a/util/iov.c
+++ b/util/iov.c
@@ -XXX,XX +XXX,XX @@ void qemu_iovec_init_extended(
 }
 
 /*
- * Check if the contents of the iovecs are all zero
+ * Check if the contents of subrange of qiov data is all zeroes.
  */
-bool qemu_iovec_is_zero(QEMUIOVector *qiov)
+bool qemu_iovec_is_zero(QEMUIOVector *qiov, size_t offset, size_t bytes)
 {
-    int i;
-    for (i = 0; i < qiov->niov; i++) {
-        size_t offs = QEMU_ALIGN_DOWN(qiov->iov[i].iov_len, 4 * sizeof(long));
-        uint8_t *ptr = qiov->iov[i].iov_base;
-        if (offs && !buffer_is_zero(qiov->iov[i].iov_base, offs)) {
+    struct iovec *iov;
+    size_t current_offset;
+
+    assert(offset + bytes <= qiov->size);
+
+    iov = iov_skip_offset(qiov->iov, offset, &current_offset);
+
+    while (bytes) {
+        uint8_t *base = (uint8_t *)iov->iov_base + current_offset;
+        size_t len = MIN(iov->iov_len - current_offset, bytes);
+
+        if (!buffer_is_zero(base, len)) {
             return false;
         }
-        for (; offs < qiov->iov[i].iov_len; offs++) {
-            if (ptr[offs]) {
-                return false;
-            }
-        }
+
+        current_offset = 0;
+        bytes -= len;
+        iov++;
     }
+
     return true;
 }
 
-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

We have similar padding code in bdrv_co_pwritev,
bdrv_co_do_pwrite_zeroes and bdrv_co_preadv. Let's combine and unify
it.

[Squashed in Vladimir's qemu-iotests 077 fix
--Stefan]

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-4-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-4-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/io.c | 365 +++++++++++++++++++++++++++++------------------------
 1 file changed, 200 insertions(+), 165 deletions(-)

diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ out:
 }
 
 /*
- * Handle a read request in coroutine context
+ * Request padding
+ *
+ *  |<---- align ----->|                     |<----- align ---->|
+ *  |<- head ->|<------------- bytes ------------->|<-- tail -->|
+ *  |          |       |                     |     |            |
+ * -*----------$-------*-------- ... --------*-----$------------*---
+ *  |          |       |                     |     |            |
+ *  |          offset  |                     |     end          |
+ *  ALIGN_DOWN(offset) ALIGN_UP(offset)      ALIGN_DOWN(end)   ALIGN_UP(end)
+ *  [buf   ... )                             [tail_buf          )
+ *
+ * @buf is an aligned allocation needed to store @head and @tail paddings. @head
+ * is placed at the beginning of @buf and @tail at the @end.
+ *
+ * @tail_buf is a pointer to sub-buffer, corresponding to align-sized chunk
+ * around tail, if tail exists.
+ *
+ * @merge_reads is true for small requests,
+ * if @buf_len == @head + bytes + @tail. In this case it is possible that both
+ * head and tail exist but @buf_len == align and @tail_buf == @buf.
  */
+typedef struct BdrvRequestPadding {
+    uint8_t *buf;
+    size_t buf_len;
+    uint8_t *tail_buf;
+    size_t head;
+    size_t tail;
+    bool merge_reads;
+    QEMUIOVector local_qiov;
+} BdrvRequestPadding;
+
+static bool bdrv_init_padding(BlockDriverState *bs,
+                              int64_t offset, int64_t bytes,
+                              BdrvRequestPadding *pad)
+{
+    uint64_t align = bs->bl.request_alignment;
+    size_t sum;
+
+    memset(pad, 0, sizeof(*pad));
+
+    pad->head = offset & (align - 1);
+    pad->tail = ((offset + bytes) & (align - 1));
+    if (pad->tail) {
+        pad->tail = align - pad->tail;
+    }
+
+    if ((!pad->head && !pad->tail) || !bytes) {
+        return false;
+    }
+
+    sum = pad->head + bytes + pad->tail;
+    pad->buf_len = (sum > align && pad->head && pad->tail) ? 2 * align : align;
+    pad->buf = qemu_blockalign(bs, pad->buf_len);
+    pad->merge_reads = sum == pad->buf_len;
+    if (pad->tail) {
+        pad->tail_buf = pad->buf + pad->buf_len - align;
+    }
+
+    return true;
+}
+
+static int bdrv_padding_rmw_read(BdrvChild *child,
+                                 BdrvTrackedRequest *req,
+                                 BdrvRequestPadding *pad,
+                                 bool zero_middle)
+{
+    QEMUIOVector local_qiov;
+    BlockDriverState *bs = child->bs;
+    uint64_t align = bs->bl.request_alignment;
+    int ret;
+
+    assert(req->serialising && pad->buf);
+
+    if (pad->head || pad->merge_reads) {
+        uint64_t bytes = pad->merge_reads ? pad->buf_len : align;
+
+        qemu_iovec_init_buf(&local_qiov, pad->buf, bytes);
+
+        if (pad->head) {
+            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
+        }
+        if (pad->merge_reads && pad->tail) {
+            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
+        }
+        ret = bdrv_aligned_preadv(child, req, req->overlap_offset, bytes,
+                                  align, &local_qiov, 0);
+        if (ret < 0) {
+            return ret;
+        }
+        if (pad->head) {
+            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
+        }
+        if (pad->merge_reads && pad->tail) {
+            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
+        }
+
+        if (pad->merge_reads) {
+            goto zero_mem;
+        }
+    }
+
+    if (pad->tail) {
+        qemu_iovec_init_buf(&local_qiov, pad->tail_buf, align);
+
+        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
+        ret = bdrv_aligned_preadv(
+                child, req,
+                req->overlap_offset + req->overlap_bytes - align,
+                align, align, &local_qiov, 0);
+        if (ret < 0) {
+            return ret;
+        }
+        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
+    }
+
+zero_mem:
+    if (zero_middle) {
+        memset(pad->buf + pad->head, 0, pad->buf_len - pad->head - pad->tail);
+    }
+
+    return 0;
+}
+
+static void bdrv_padding_destroy(BdrvRequestPadding *pad)
+{
+    if (pad->buf) {
+        qemu_vfree(pad->buf);
+        qemu_iovec_destroy(&pad->local_qiov);
+    }
+}
+
+/*
+ * bdrv_pad_request
+ *
+ * Exchange request parameters with padded request if needed. Don't include RMW
+ * read of padding, bdrv_padding_rmw_read() should be called separately if
+ * needed.
+ *
+ * All parameters except @bs are in-out: they represent original request at
+ * function call and padded (if padding needed) at function finish.
+ *
+ * Function always succeeds.
+ */
+static bool bdrv_pad_request(BlockDriverState *bs, QEMUIOVector **qiov,
+                             int64_t *offset, unsigned int *bytes,
+                             BdrvRequestPadding *pad)
+{
+    if (!bdrv_init_padding(bs, *offset, *bytes, pad)) {
+        return false;
+    }
+
+    qemu_iovec_init_extended(&pad->local_qiov, pad->buf, pad->head,
+                             *qiov, 0, *bytes,
+                             pad->buf + pad->buf_len - pad->tail, pad->tail);
+    *bytes += pad->head + pad->tail;
+    *offset -= pad->head;
+    *qiov = &pad->local_qiov;
+
+    return true;
+}
+
 int coroutine_fn bdrv_co_preadv(BdrvChild *child,
     int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
     BdrvRequestFlags flags)
 {
     BlockDriverState *bs = child->bs;
-    BlockDriver *drv = bs->drv;
     BdrvTrackedRequest req;
-
-    uint64_t align = bs->bl.request_alignment;
-    uint8_t *head_buf = NULL;
-    uint8_t *tail_buf = NULL;
-    QEMUIOVector local_qiov;
-    bool use_local_qiov = false;
+    BdrvRequestPadding pad;
     int ret;
 
-    trace_bdrv_co_preadv(child->bs, offset, bytes, flags);
-
-    if (!drv) {
-        return -ENOMEDIUM;
-    }
+    trace_bdrv_co_preadv(bs, offset, bytes, flags);
 
     ret = bdrv_check_byte_request(bs, offset, bytes);
     if (ret < 0) {
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child,
         flags |= BDRV_REQ_COPY_ON_READ;
     }
 
-    /* Align read if necessary by padding qiov */
-    if (offset & (align - 1)) {
-        head_buf = qemu_blockalign(bs, align);
-        qemu_iovec_init(&local_qiov, qiov->niov + 2);
-        qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1));
-        qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
-        use_local_qiov = true;
-
-        bytes += offset & (align - 1);
-        offset = offset & ~(align - 1);
-    }
-
-    if ((offset + bytes) & (align - 1)) {
-        if (!use_local_qiov) {
-            qemu_iovec_init(&local_qiov, qiov->niov + 1);
-            qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
-            use_local_qiov = true;
-        }
-        tail_buf = qemu_blockalign(bs, align);
-        qemu_iovec_add(&local_qiov, tail_buf,
-                       align - ((offset + bytes) & (align - 1)));
-
-        bytes = ROUND_UP(bytes, align);
-    }
+    bdrv_pad_request(bs, &qiov, &offset, &bytes, &pad);
 
     tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_READ);
-    ret = bdrv_aligned_preadv(child, &req, offset, bytes, align,
-                              use_local_qiov ? &local_qiov : qiov,
-                              flags);
+    ret = bdrv_aligned_preadv(child, &req, offset, bytes,
+                              bs->bl.request_alignment,
+                              qiov, flags);
     tracked_request_end(&req);
     bdrv_dec_in_flight(bs);
 
-    if (use_local_qiov) {
-        qemu_iovec_destroy(&local_qiov);
-        qemu_vfree(head_buf);
-        qemu_vfree(tail_buf);
-    }
+    bdrv_padding_destroy(&pad);
 
     return ret;
 }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
                                                 BdrvTrackedRequest *req)
 {
     BlockDriverState *bs = child->bs;
-    uint8_t *buf = NULL;
     QEMUIOVector local_qiov;
     uint64_t align = bs->bl.request_alignment;
-    unsigned int head_padding_bytes, tail_padding_bytes;
     int ret = 0;
+    bool padding;
+    BdrvRequestPadding pad;
 
-    head_padding_bytes = offset & (align - 1);
-    tail_padding_bytes = (align - (offset + bytes)) & (align - 1);
-
-
-    assert(flags & BDRV_REQ_ZERO_WRITE);
-    if (head_padding_bytes || tail_padding_bytes) {
-        buf = qemu_blockalign(bs, align);
-        qemu_iovec_init_buf(&local_qiov, buf, align);
-    }
-    if (head_padding_bytes) {
-        uint64_t zero_bytes = MIN(bytes, align - head_padding_bytes);
-
-        /* RMW the unaligned part before head. */
+    padding = bdrv_init_padding(bs, offset, bytes, &pad);
+    if (padding) {
         mark_request_serialising(req, align);
         wait_serialising_requests(req);
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
-        ret = bdrv_aligned_preadv(child, req, offset & ~(align - 1), align,
-                                  align, &local_qiov, 0);
-        if (ret < 0) {
-            goto fail;
-        }
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
 
-        memset(buf + head_padding_bytes, 0, zero_bytes);
-        ret = bdrv_aligned_pwritev(child, req, offset & ~(align - 1), align,
-                                   align, &local_qiov,
-                                   flags & ~BDRV_REQ_ZERO_WRITE);
-        if (ret < 0) {
-            goto fail;
+        bdrv_padding_rmw_read(child, req, &pad, true);
+
+        if (pad.head || pad.merge_reads) {
+            int64_t aligned_offset = offset & ~(align - 1);
+            int64_t write_bytes = pad.merge_reads ? pad.buf_len : align;
+
+            qemu_iovec_init_buf(&local_qiov, pad.buf, write_bytes);
+            ret = bdrv_aligned_pwritev(child, req, aligned_offset, write_bytes,
+                                       align, &local_qiov,
+                                       flags & ~BDRV_REQ_ZERO_WRITE);
+            if (ret < 0 || pad.merge_reads) {
+                /* Error or all work is done */
+                goto out;
+            }
+            offset += write_bytes - pad.head;
+            bytes -= write_bytes - pad.head;
         }
-        offset += zero_bytes;
-        bytes -= zero_bytes;
     }
 
     assert(!bytes || (offset & (align - 1)) == 0);
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
         ret = bdrv_aligned_pwritev(child, req, offset, aligned_bytes, align,
                                    NULL, flags);
         if (ret < 0) {
-            goto fail;
+            goto out;
         }
         bytes -= aligned_bytes;
         offset += aligned_bytes;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
 
     assert(!bytes || (offset & (align - 1)) == 0);
     if (bytes) {
-        assert(align == tail_padding_bytes + bytes);
-        /* RMW the unaligned part after tail. */
-        mark_request_serialising(req, align);
-        wait_serialising_requests(req);
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
-        ret = bdrv_aligned_preadv(child, req, offset, align,
-                                  align, &local_qiov, 0);
-        if (ret < 0) {
-            goto fail;
-        }
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
+        assert(align == pad.tail + bytes);
 
-        memset(buf, 0, bytes);
+        qemu_iovec_init_buf(&local_qiov, pad.tail_buf, align);
         ret = bdrv_aligned_pwritev(child, req, offset, align, align,
                                    &local_qiov, flags & ~BDRV_REQ_ZERO_WRITE);
     }
-fail:
-    qemu_vfree(buf);
+
+out:
+    bdrv_padding_destroy(&pad);
+
     return ret;
-
 }
 
 /*
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
     BlockDriverState *bs = child->bs;
     BdrvTrackedRequest req;
     uint64_t align = bs->bl.request_alignment;
-    uint8_t *head_buf = NULL;
-    uint8_t *tail_buf = NULL;
-    QEMUIOVector local_qiov;
-    bool use_local_qiov = false;
+    BdrvRequestPadding pad;
     int ret;
 
     trace_bdrv_co_pwritev(child->bs, offset, bytes, flags);
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
         goto out;
     }
 
-    if (offset & (align - 1)) {
-        QEMUIOVector head_qiov;
-
+    if (bdrv_pad_request(bs, &qiov, &offset, &bytes, &pad)) {
         mark_request_serialising(&req, align);
         wait_serialising_requests(&req);
-
-        head_buf = qemu_blockalign(bs, align);
-        qemu_iovec_init_buf(&head_qiov, head_buf, align);
-
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
-        ret = bdrv_aligned_preadv(child, &req, offset & ~(align - 1), align,
-                                  align, &head_qiov, 0);
-        if (ret < 0) {
-            goto fail;
-        }
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
-
-        qemu_iovec_init(&local_qiov, qiov->niov + 2);
-        qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1));
-        qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
-        use_local_qiov = true;
-
-        bytes += offset & (align - 1);
-        offset = offset & ~(align - 1);
-
-        /* We have read the tail already if the request is smaller
-         * than one aligned block.
-         */
-        if (bytes < align) {
-            qemu_iovec_add(&local_qiov, head_buf + bytes, align - bytes);
-            bytes = align;
-        }
-    }
-
-    if ((offset + bytes) & (align - 1)) {
-        QEMUIOVector tail_qiov;
-        size_t tail_bytes;
-        bool waited;
-
-        mark_request_serialising(&req, align);
-        waited = wait_serialising_requests(&req);
-        assert(!waited || !use_local_qiov);
-
-        tail_buf = qemu_blockalign(bs, align);
-        qemu_iovec_init_buf(&tail_qiov, tail_buf, align);
-
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
-        ret = bdrv_aligned_preadv(child, &req, (offset + bytes) & ~(align - 1),
-                                  align, align, &tail_qiov, 0);
-        if (ret < 0) {
-            goto fail;
-        }
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
-
-        if (!use_local_qiov) {
-            qemu_iovec_init(&local_qiov, qiov->niov + 1);
-            qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
-            use_local_qiov = true;
-        }
-
-        tail_bytes = (offset + bytes) & (align - 1);
-        qemu_iovec_add(&local_qiov, tail_buf + tail_bytes, align - tail_bytes);
-
-        bytes = ROUND_UP(bytes, align);
+        bdrv_padding_rmw_read(child, &req, &pad, false);
     }
 
     ret = bdrv_aligned_pwritev(child, &req, offset, bytes, align,
-                               use_local_qiov ? &local_qiov : qiov,
-                               flags);
+                               qiov, flags);
 
-fail:
+    bdrv_padding_destroy(&pad);
 
-    if (use_local_qiov) {
-        qemu_iovec_destroy(&local_qiov);
-    }
-    qemu_vfree(head_buf);
-    qemu_vfree(tail_buf);
 out:
     tracked_request_end(&req);
     bdrv_dec_in_flight(bs);
+
     return ret;
 }
 
-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Add handlers supporting qiov_offset parameter:
    bdrv_co_preadv_part
    bdrv_co_pwritev_part
    bdrv_co_pwritev_compressed_part
This is used to reduce need of defining local_qiovs and hd_qiovs in all
corners of block layer code. The following patches will increase usage
of this new API part by part.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-5-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-5-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/block/block_int.h | 15 ++++++
 block/backup.c            |  2 +-
 block/io.c                | 96 +++++++++++++++++++++++++++++++--------
 qemu-img.c                |  4 +-
 4 files changed, 95 insertions(+), 22 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -XXX,XX +XXX,XX @@ struct BlockDriver {
      */
     int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs,
         uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags);
+    int coroutine_fn (*bdrv_co_preadv_part)(BlockDriverState *bs,
+        uint64_t offset, uint64_t bytes,
+        QEMUIOVector *qiov, size_t qiov_offset, int flags);
     int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags);
     /**
@@ -XXX,XX +XXX,XX @@ struct BlockDriver {
      */
     int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs,
         uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags);
+    int coroutine_fn (*bdrv_co_pwritev_part)(BlockDriverState *bs,
+        uint64_t offset, uint64_t bytes,
+        QEMUIOVector *qiov, size_t qiov_offset, int flags);
 
     /*
      * Efficiently zero a region of the disk image.  Typically an image format
@@ -XXX,XX +XXX,XX @@ struct BlockDriver {
 
     int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs,
         uint64_t offset, uint64_t bytes, QEMUIOVector *qiov);
+    int coroutine_fn (*bdrv_co_pwritev_compressed_part)(BlockDriverState *bs,
+        uint64_t offset, uint64_t bytes, QEMUIOVector *qiov,
+        size_t qiov_offset);
 
     int (*bdrv_snapshot_create)(BlockDriverState *bs,
                                 QEMUSnapshotInfo *sn_info);
@@ -XXX,XX +XXX,XX @@ struct BlockDriver {
     const char *const *strong_runtime_opts;
 };
 
+static inline bool block_driver_can_compress(BlockDriver *drv)
+{
+    return drv->bdrv_co_pwritev_compressed ||
+           drv->bdrv_co_pwritev_compressed_part;
+}
+
 typedef struct BlockLimits {
     /* Alignment requirement, in bytes, for offset/length of I/O
      * requests. Must be a power of 2 less than INT_MAX; defaults to
diff --git a/block/backup.c b/block/backup.c
index XXXXXXX..XXXXXXX 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -XXX,XX +XXX,XX @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
         return NULL;
     }
 
-    if (compress && target->drv->bdrv_co_pwritev_compressed == NULL) {
+    if (compress && !block_driver_can_compress(target->drv)) {
         error_setg(errp, "Compression is not supported for this drive %s",
                    bdrv_get_device_name(target));
         return NULL;
diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
 
     /* Default alignment based on whether driver has byte interface */
     bs->bl.request_alignment = (drv->bdrv_co_preadv ||
-                                drv->bdrv_aio_preadv) ? 1 : 512;
+                                drv->bdrv_aio_preadv ||
+                                drv->bdrv_co_preadv_part) ? 1 : 512;
 
     /* Take some limits from the children as a default */
     if (bs->file) {
@@ -XXX,XX +XXX,XX @@ static void bdrv_co_io_em_complete(void *opaque, int ret)
 
 static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
                                            uint64_t offset, uint64_t bytes,
-                                           QEMUIOVector *qiov, int flags)
+                                           QEMUIOVector *qiov,
+                                           size_t qiov_offset, int flags)
 {
     BlockDriver *drv = bs->drv;
     int64_t sector_num;
     unsigned int nb_sectors;
+    QEMUIOVector local_qiov;
+    int ret;
 
     assert(!(flags & ~BDRV_REQ_MASK));
     assert(!(flags & BDRV_REQ_NO_FALLBACK));
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
         return -ENOMEDIUM;
     }
 
+    if (drv->bdrv_co_preadv_part) {
+        return drv->bdrv_co_preadv_part(bs, offset, bytes, qiov, qiov_offset,
+                                        flags);
+    }
+
+    if (qiov_offset > 0 || bytes != qiov->size) {
+        qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
+        qiov = &local_qiov;
+    }
+
     if (drv->bdrv_co_preadv) {
-        return drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags);
+        ret = drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags);
+        goto out;
     }
 
     if (drv->bdrv_aio_preadv) {
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
         acb = drv->bdrv_aio_preadv(bs, offset, bytes, qiov, flags,
                                    bdrv_co_io_em_complete, &co);
         if (acb == NULL) {
-            return -EIO;
+            ret = -EIO;
+            goto out;
         } else {
             qemu_coroutine_yield();
-            return co.ret;
+            ret = co.ret;
+            goto out;
         }
     }
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
     assert(bytes <= BDRV_REQUEST_MAX_BYTES);
     assert(drv->bdrv_co_readv);
 
-    return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
+    ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
+
+out:
+    if (qiov == &local_qiov) {
+        qemu_iovec_destroy(&local_qiov);
+    }
+
+    return ret;
 }
 
 static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
                                             uint64_t offset, uint64_t bytes,
-                                            QEMUIOVector *qiov, int flags)
+                                            QEMUIOVector *qiov,
+                                            size_t qiov_offset, int flags)
 {
     BlockDriver *drv = bs->drv;
     int64_t sector_num;
     unsigned int nb_sectors;
+    QEMUIOVector local_qiov;
     int ret;
 
     assert(!(flags & ~BDRV_REQ_MASK));
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
         return -ENOMEDIUM;
     }
 
+    if (drv->bdrv_co_pwritev_part) {
+        ret = drv->bdrv_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset,
+                                        flags & bs->supported_write_flags);
+        flags &= ~bs->supported_write_flags;
+        goto emulate_flags;
+    }
+
+    if (qiov_offset > 0 || bytes != qiov->size) {
+        qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
+        qiov = &local_qiov;
+    }
+
     if (drv->bdrv_co_pwritev) {
         ret = drv->bdrv_co_pwritev(bs, offset, bytes, qiov,
                                    flags & bs->supported_write_flags);
@@ -XXX,XX +XXX,XX @@ emulate_flags:
         ret = bdrv_co_flush(bs);
     }
 
+    if (qiov == &local_qiov) {
+        qemu_iovec_destroy(&local_qiov);
+    }
+
     return ret;
 }
 
 static int coroutine_fn
 bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
-                               uint64_t bytes, QEMUIOVector *qiov)
+                               uint64_t bytes, QEMUIOVector *qiov,
+                               size_t qiov_offset)
 {
     BlockDriver *drv = bs->drv;
+    QEMUIOVector local_qiov;
+    int ret;
 
     if (!drv) {
         return -ENOMEDIUM;
     }
 
-    if (!drv->bdrv_co_pwritev_compressed) {
+    if (!block_driver_can_compress(drv)) {
         return -ENOTSUP;
     }
 
-    return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov);
+    if (drv->bdrv_co_pwritev_compressed_part) {
+        return drv->bdrv_co_pwritev_compressed_part(bs, offset, bytes,
+                                                    qiov, qiov_offset);
+    }
+
+    if (qiov_offset == 0) {
+        return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov);
+    }
+
+    qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
+    ret = drv->bdrv_co_pwritev_compressed(bs, offset, bytes, &local_qiov);
+    qemu_iovec_destroy(&local_qiov);
+
+    return ret;
 }
 
 static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
             qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);
 
             ret = bdrv_driver_preadv(bs, cluster_offset, pnum,
-                                     &local_qiov, 0);
+                                     &local_qiov, 0, 0);
             if (ret < 0) {
                 goto err;
             }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
                  * necessary to flush even in cache=writethrough mode.
                  */
                 ret = bdrv_driver_pwritev(bs, cluster_offset, pnum,
-                                          &local_qiov,
+                                          &local_qiov, 0,
                                           BDRV_REQ_WRITE_UNCHANGED);
             }
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
             qemu_iovec_init(&local_qiov, qiov->niov);
             qemu_iovec_concat(&local_qiov, qiov, progress, pnum - skip_bytes);
             ret = bdrv_driver_preadv(bs, offset + progress, local_qiov.size,
-                                     &local_qiov, 0);
+                                     &local_qiov, 0, 0);
             qemu_iovec_destroy(&local_qiov);
             if (ret < 0) {
                 goto err;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
 
     max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
     if (bytes <= max_bytes && bytes <= max_transfer) {
-        ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0);
+        ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0, 0);
         goto out;
     }
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
             qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
 
             ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining,
-                                     num, &local_qiov, 0);
+                                     num, &local_qiov, 0, 0);
             max_bytes -= num;
             qemu_iovec_destroy(&local_qiov);
         } else {
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
             }
             qemu_iovec_init_buf(&qiov, buf, num);
 
-            ret = bdrv_driver_pwritev(bs, offset, num, &qiov, write_flags);
+            ret = bdrv_driver_pwritev(bs, offset, num, &qiov, 0, write_flags);
 
             /* Keep bounce buffer around if it is big enough for all
              * all future requests.
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
         bdrv_debug_event(bs, BLKDBG_PWRITEV_ZERO);
         ret = bdrv_co_do_pwrite_zeroes(bs, offset, bytes, flags);
     } else if (flags & BDRV_REQ_WRITE_COMPRESSED) {
-        ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, qiov);
+        ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, qiov, 0);
     } else if (bytes <= max_transfer) {
         bdrv_debug_event(bs, BLKDBG_PWRITEV);
-        ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, flags);
+        ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, 0, flags);
     } else {
         bdrv_debug_event(bs, BLKDBG_PWRITEV);
         while (bytes_remaining) {
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
             qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
 
             ret = bdrv_driver_pwritev(bs, offset + bytes - bytes_remaining,
-                                      num, &local_qiov, local_flags);
+                                      num, &local_qiov, 0, local_flags);
             qemu_iovec_destroy(&local_qiov);
             if (ret < 0) {
                 break;
diff --git a/qemu-img.c b/qemu-img.c
index XXXXXXX..XXXXXXX 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -XXX,XX +XXX,XX @@ static int img_convert(int argc, char **argv)
         const char *preallocation =
             qemu_opt_get(opts, BLOCK_OPT_PREALLOC);
 
-        if (drv && !drv->bdrv_co_pwritev_compressed) {
+        if (drv && !block_driver_can_compress(drv)) {
             error_report("Compression not supported for this file format");
             ret = -1;
             goto out;
@@ -XXX,XX +XXX,XX @@ static int img_convert(int argc, char **argv)
     }
     out_bs = blk_bs(s.target);
 
-    if (s.compressed && !out_bs->drv->bdrv_co_pwritev_compressed) {
+    if (s.compressed && !block_driver_can_compress(out_bs->drv)) {
         error_report("Compression not supported for this file format");
         ret = -1;
         goto out;
-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Use and support new API in bdrv_co_do_copy_on_readv. Note that in case
of allocated-in-top we need to shrink read size to MIN(..) by hand, as
pre-patch this was actually done implicitly by qemu_iovec_concat (and
we used local_qiov.size).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-6-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-6-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/io.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
 
 static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
         int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
-        int flags)
+        size_t qiov_offset, int flags)
 {
     BlockDriverState *bs = child->bs;
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
     void *bounce_buffer;
 
     BlockDriver *drv = bs->drv;
-    QEMUIOVector local_qiov;
     int64_t cluster_offset;
     int64_t cluster_bytes;
     size_t skip_bytes;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
         assert(skip_bytes < pnum);
 
         if (ret <= 0) {
+            QEMUIOVector local_qiov;
+
             /* Must copy-on-read; use the bounce buffer */
             pnum = MIN(pnum, MAX_BOUNCE_BUFFER);
             qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
             }
 
             if (!(flags & BDRV_REQ_PREFETCH)) {
-                qemu_iovec_from_buf(qiov, progress, bounce_buffer + skip_bytes,
+                qemu_iovec_from_buf(qiov, qiov_offset + progress,
+                                    bounce_buffer + skip_bytes,
                                     pnum - skip_bytes);
             }
         } else if (!(flags & BDRV_REQ_PREFETCH)) {
             /* Read directly into the destination */
-            qemu_iovec_init(&local_qiov, qiov->niov);
-            qemu_iovec_concat(&local_qiov, qiov, progress, pnum - skip_bytes);
-            ret = bdrv_driver_preadv(bs, offset + progress, local_qiov.size,
-                                     &local_qiov, 0, 0);
-            qemu_iovec_destroy(&local_qiov);
+            ret = bdrv_driver_preadv(bs, offset + progress,
+                                     MIN(pnum - skip_bytes, bytes - progress),
+                                     qiov, qiov_offset + progress, 0);
             if (ret < 0) {
                 goto err;
             }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
         }
 
         if (!ret || pnum != bytes) {
-            ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, flags);
+            ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, 0, flags);
             goto out;
         } else if (flags & BDRV_REQ_PREFETCH) {
             goto out;
-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Allocate bounce_buffer only if it is really needed. Also, sub-optimize
allocation size (why not?).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-7-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-7-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/io.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
      * modifying the image file.  This is critical for zero-copy guest I/O
      * where anything might happen inside guest memory.
      */
-    void *bounce_buffer;
+    void *bounce_buffer = NULL;
 
     BlockDriver *drv = bs->drv;
     int64_t cluster_offset;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
     trace_bdrv_co_do_copy_on_readv(bs, offset, bytes,
                                    cluster_offset, cluster_bytes);
 
-    bounce_buffer = qemu_try_blockalign(bs,
-                                        MIN(MIN(max_transfer, cluster_bytes),
-                                            MAX_BOUNCE_BUFFER));
-    if (bounce_buffer == NULL) {
-        ret = -ENOMEM;
-        goto err;
-    }
-
     while (cluster_bytes) {
         int64_t pnum;
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
 
             /* Must copy-on-read; use the bounce buffer */
             pnum = MIN(pnum, MAX_BOUNCE_BUFFER);
+            if (!bounce_buffer) {
+                int64_t max_we_need = MAX(pnum, cluster_bytes - pnum);
+                int64_t max_allowed = MIN(max_transfer, MAX_BOUNCE_BUFFER);
+                int64_t bounce_buffer_len = MIN(max_we_need, max_allowed);
+
+                bounce_buffer = qemu_try_blockalign(bs, bounce_buffer_len);
+                if (!bounce_buffer) {
+                    ret = -ENOMEM;
+                    goto err;
+                }
+            }
             qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);
 
             ret = bdrv_driver_preadv(bs, cluster_offset, pnum,
-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Use and support new API in bdrv_co_do_copy_on_readv.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-8-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-8-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/io.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ err:
  */
 static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
     BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
-    int64_t align, QEMUIOVector *qiov, int flags)
+    int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
 {
     BlockDriverState *bs = child->bs;
     int64_t total_bytes, max_bytes;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
     assert(is_power_of_2(align));
     assert((offset & (align - 1)) == 0);
     assert((bytes & (align - 1)) == 0);
-    assert(!qiov || bytes == qiov->size);
     assert((bs->open_flags & BDRV_O_NO_IO) == 0);
     max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX),
                                    align);
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
         }
 
         if (!ret || pnum != bytes) {
-            ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, 0, flags);
+            ret = bdrv_co_do_copy_on_readv(child, offset, bytes,
+                                           qiov, qiov_offset, flags);
             goto out;
         } else if (flags & BDRV_REQ_PREFETCH) {
             goto out;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
 
     max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
     if (bytes <= max_bytes && bytes <= max_transfer) {
-        ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0, 0);
+        ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, 0);
         goto out;
     }
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
         int num;
 
         if (max_bytes) {
-            QEMUIOVector local_qiov;
-
             num = MIN(bytes_remaining, MIN(max_bytes, max_transfer));
             assert(num);
-            qemu_iovec_init(&local_qiov, qiov->niov);
-            qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
 
             ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining,
-                                     num, &local_qiov, 0, 0);
+                                     num, qiov, bytes - bytes_remaining, 0);
             max_bytes -= num;
-            qemu_iovec_destroy(&local_qiov);
         } else {
             num = bytes_remaining;
             ret = qemu_iovec_memset(qiov, bytes - bytes_remaining, 0,
@@ -XXX,XX +XXX,XX @@ static int bdrv_padding_rmw_read(BdrvChild *child,
             bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
         }
         ret = bdrv_aligned_preadv(child, req, req->overlap_offset, bytes,
-                                  align, &local_qiov, 0);
+                                  align, &local_qiov, 0, 0);
         if (ret < 0) {
             return ret;
         }
@@ -XXX,XX +XXX,XX @@ static int bdrv_padding_rmw_read(BdrvChild *child,
         ret = bdrv_aligned_preadv(
                 child, req,
                 req->overlap_offset + req->overlap_bytes - align,
-                align, align, &local_qiov, 0);
+                align, align, &local_qiov, 0, 0);
         if (ret < 0) {
             return ret;
         }
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child,
     tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_READ);
     ret = bdrv_aligned_preadv(child, &req, offset, bytes,
                               bs->bl.request_alignment,
-                              qiov, flags);
+                              qiov, 0, flags);
     tracked_request_end(&req);
     bdrv_dec_in_flight(bs);
 
-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Use and support new API in bdrv_aligned_pwritev.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-9-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-9-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/io.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, uint64_t bytes,
  */
 static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
     BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
-    int64_t align, QEMUIOVector *qiov, int flags)
+    int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
 {
     BlockDriverState *bs = child->bs;
     BlockDriver *drv = bs->drv;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
     assert(is_power_of_2(align));
     assert((offset & (align - 1)) == 0);
     assert((bytes & (align - 1)) == 0);
-    assert(!qiov || bytes == qiov->size);
+    assert(!qiov || qiov_offset + bytes <= qiov->size);
     max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX),
                                    align);
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
 
     if (!ret && bs->detect_zeroes != BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF &&
         !(flags & BDRV_REQ_ZERO_WRITE) && drv->bdrv_co_pwrite_zeroes &&
-        qemu_iovec_is_zero(qiov, 0, qiov->size)) {
+        qemu_iovec_is_zero(qiov, qiov_offset, bytes)) {
         flags |= BDRV_REQ_ZERO_WRITE;
         if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) {
             flags |= BDRV_REQ_MAY_UNMAP;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
         bdrv_debug_event(bs, BLKDBG_PWRITEV_ZERO);
         ret = bdrv_co_do_pwrite_zeroes(bs, offset, bytes, flags);
     } else if (flags & BDRV_REQ_WRITE_COMPRESSED) {
-        ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, qiov, 0);
+        ret = bdrv_driver_pwritev_compressed(bs, offset, bytes,
+                                             qiov, qiov_offset);
     } else if (bytes <= max_transfer) {
         bdrv_debug_event(bs, BLKDBG_PWRITEV);
-        ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, 0, flags);
+        ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, qiov_offset, flags);
     } else {
         bdrv_debug_event(bs, BLKDBG_PWRITEV);
         while (bytes_remaining) {
             int num = MIN(bytes_remaining, max_transfer);
-            QEMUIOVector local_qiov;
             int local_flags = flags;
 
             assert(num);
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
                  * need to flush on the last iteration */
                 local_flags &= ~BDRV_REQ_FUA;
             }
-            qemu_iovec_init(&local_qiov, qiov->niov);
-            qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
 
             ret = bdrv_driver_pwritev(bs, offset + bytes - bytes_remaining,
-                                      num, &local_qiov, 0, local_flags);
-            qemu_iovec_destroy(&local_qiov);
+                                      num, qiov, bytes - bytes_remaining,
+                                      local_flags);
             if (ret < 0) {
                 break;
             }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
 
             qemu_iovec_init_buf(&local_qiov, pad.buf, write_bytes);
             ret = bdrv_aligned_pwritev(child, req, aligned_offset, write_bytes,
-                                       align, &local_qiov,
+                                       align, &local_qiov, 0,
                                        flags & ~BDRV_REQ_ZERO_WRITE);
             if (ret < 0 || pad.merge_reads) {
                 /* Error or all work is done */
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
         /* Write the aligned part in the middle. */
         uint64_t aligned_bytes = bytes & ~(align - 1);
         ret = bdrv_aligned_pwritev(child, req, offset, aligned_bytes, align,
-                                   NULL, flags);
+                                   NULL, 0, flags);
         if (ret < 0) {
             goto out;
         }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
 
         qemu_iovec_init_buf(&local_qiov, pad.tail_buf, align);
         ret = bdrv_aligned_pwritev(child, req, offset, align, align,
-                                   &local_qiov, flags & ~BDRV_REQ_ZERO_WRITE);
+                                   &local_qiov, 0,
+                                   flags & ~BDRV_REQ_ZERO_WRITE);
     }
 
 out:
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
     }
 
     ret = bdrv_aligned_pwritev(child, &req, offset, bytes, align,
-                               qiov, flags);
+                               qiov, 0, flags);
 
     bdrv_padding_destroy(&pad);
 
-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Introduce extended variants of bdrv_co_preadv and bdrv_co_pwritev
with qiov_offset parameter.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-10-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-10-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/block/block_int.h |  6 ++++++
 block/io.c                | 29 +++++++++++++++++++++++------
 2 files changed, 29 insertions(+), 6 deletions(-)

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Use buffer based io in encrypted case.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-11-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-11-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/qcow2.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
                 }
 
                 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
-                qemu_iovec_reset(&hd_qiov);
-                qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
-            }
 
-            BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
-            ret = bdrv_co_preadv(s->data_file,
-                                 cluster_offset + offset_in_cluster,
-                                 cur_bytes, &hd_qiov, 0);
-            if (ret < 0) {
-                goto fail;
-            }
-            if (bs->encrypted) {
-                assert(s->crypto);
+                BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
+                ret = bdrv_co_pread(s->data_file,
+                                    cluster_offset + offset_in_cluster,
+                                    cur_bytes, cluster_data, 0);
+                if (ret < 0) {
+                    goto fail;
+                }
+
                 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
                 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
                 if (qcow2_co_decrypt(bs, cluster_offset, offset,
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
                     goto fail;
                 }
                 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes);
+            } else {
+                BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
+                ret = bdrv_co_preadv(s->data_file,
+                                     cluster_offset + offset_in_cluster,
+                                     cur_bytes, &hd_qiov, 0);
+                if (ret < 0) {
+                    goto fail;
+                }
             }
             break;
 
-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Implement and use new interface to get rid of hd_qiov.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-12-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-12-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/qcow2-cluster.c |  5 +++--
 block/qcow2.c         | 49 +++++++++++++++++++------------------------
 2 files changed, 25 insertions(+), 29 deletions(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn do_perform_cow_read(BlockDriverState *bs,
      * interface.  This avoids double I/O throttling and request tracking,
      * which can lead to deadlock when block layer copy-on-read is enabled.
      */
-    ret = bs->drv->bdrv_co_preadv(bs, src_cluster_offset + offset_in_cluster,
-                                  qiov->size, qiov, 0);
+    ret = bs->drv->bdrv_co_preadv_part(bs,
+                                       src_cluster_offset + offset_in_cluster,
+                                       qiov->size, qiov, 0, 0);
     if (ret < 0) {
         return ret;
     }
diff --git a/block/qcow2.c b/block/qcow2.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -XXX,XX +XXX,XX @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
                            uint64_t file_cluster_offset,
                            uint64_t offset,
                            uint64_t bytes,
-                           QEMUIOVector *qiov);
+                           QEMUIOVector *qiov,
+                           size_t qiov_offset);
 
 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
 {
@@ -XXX,XX +XXX,XX @@ out:
     return ret;
 }
 
-static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
-                                        uint64_t bytes, QEMUIOVector *qiov,
-                                        int flags)
+static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs,
+                                             uint64_t offset, uint64_t bytes,
+                                             QEMUIOVector *qiov,
+                                             size_t qiov_offset, int flags)
 {
     BDRVQcow2State *s = bs->opaque;
     int offset_in_cluster;
     int ret;
     unsigned int cur_bytes; /* number of bytes in current iteration */
     uint64_t cluster_offset = 0;
-    uint64_t bytes_done = 0;
-    QEMUIOVector hd_qiov;
     uint8_t *cluster_data = NULL;
 
-    qemu_iovec_init(&hd_qiov, qiov->niov);
-
     while (bytes != 0) {
 
         /* prepare next request */
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
 
         offset_in_cluster = offset_into_cluster(s, offset);
 
-        qemu_iovec_reset(&hd_qiov);
-        qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
-
         switch (ret) {
         case QCOW2_CLUSTER_UNALLOCATED:
 
             if (bs->backing) {
                 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
-                ret = bdrv_co_preadv(bs->backing, offset, cur_bytes,
-                                     &hd_qiov, 0);
+                ret = bdrv_co_preadv_part(bs->backing, offset, cur_bytes,
+                                          qiov, qiov_offset, 0);
                 if (ret < 0) {
                     goto fail;
                 }
             } else {
                 /* Note: in this case, no need to wait */
-                qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
+                qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes);
             }
             break;
 
         case QCOW2_CLUSTER_ZERO_PLAIN:
         case QCOW2_CLUSTER_ZERO_ALLOC:
-            qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
+            qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes);
             break;
 
         case QCOW2_CLUSTER_COMPRESSED:
             ret = qcow2_co_preadv_compressed(bs, cluster_offset,
                                              offset, cur_bytes,
-                                             &hd_qiov);
+                                             qiov, qiov_offset);
             if (ret < 0) {
                 goto fail;
             }
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
                     ret = -EIO;
                     goto fail;
                 }
-                qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes);
+                qemu_iovec_from_buf(qiov, qiov_offset, cluster_data, cur_bytes);
             } else {
                 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
-                ret = bdrv_co_preadv(s->data_file,
-                                     cluster_offset + offset_in_cluster,
-                                     cur_bytes, &hd_qiov, 0);
+                ret = bdrv_co_preadv_part(s->data_file,
+                                          cluster_offset + offset_in_cluster,
+                                          cur_bytes, qiov, qiov_offset, 0);
                 if (ret < 0) {
                     goto fail;
                 }
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
 
         bytes -= cur_bytes;
         offset += cur_bytes;
-        bytes_done += cur_bytes;
+        qiov_offset += cur_bytes;
     }
     ret = 0;
 
 fail:
-    qemu_iovec_destroy(&hd_qiov);
     qemu_vfree(cluster_data);
 
     return ret;
@@ -XXX,XX +XXX,XX @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
                            uint64_t file_cluster_offset,
                            uint64_t offset,
                            uint64_t bytes,
-                           QEMUIOVector *qiov)
+                           QEMUIOVector *qiov,
+                           size_t qiov_offset)
 {
     BDRVQcow2State *s = bs->opaque;
     int ret = 0, csize, nb_csectors;
@@ -XXX,XX +XXX,XX @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
         goto fail;
     }
 
-    qemu_iovec_from_buf(qiov, 0, out_buf + offset_in_cluster, bytes);
+    qemu_iovec_from_buf(qiov, qiov_offset, out_buf + offset_in_cluster, bytes);
 
 fail:
     qemu_vfree(out_buf);
@@ -XXX,XX +XXX,XX @@ static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
     BDRVQcow2State *s = bs->opaque;
 
     BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
-    return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos,
-                                   qiov->size, qiov, 0);
+    return bs->drv->bdrv_co_preadv_part(bs, qcow2_vm_state_offset(s) + pos,
+                                        qiov->size, qiov, 0, 0);
 }
 
 /*
@@ -XXX,XX +XXX,XX @@ BlockDriver bdrv_qcow2 = {
     .bdrv_has_zero_init_truncate = bdrv_has_zero_init_1,
     .bdrv_co_block_status = qcow2_co_block_status,
 
-    .bdrv_co_preadv         = qcow2_co_preadv,
+    .bdrv_co_preadv_part    = qcow2_co_preadv_part,
     .bdrv_co_pwritev        = qcow2_co_pwritev,
     .bdrv_co_flush_to_os    = qcow2_co_flush_to_os,
 
-- 
2.21.0

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Implement and use new interface to get rid of hd_qiov.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-13-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-13-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/qcow2.h         |  1 +
 include/qemu/iov.h    |  1 +
 block/qcow2-cluster.c |  9 ++++---
 block/qcow2.c         | 60 +++++++++++++++++++++----------------------
 util/iov.c            | 10 ++++++++
 5 files changed, 48 insertions(+), 33 deletions(-)

diff --git a/block/qcow2.h b/block/qcow2.h
index XXXXXXX..XXXXXXX 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -XXX,XX +XXX,XX @@ typedef struct QCowL2Meta
      * from @cow_start and @cow_end into one single write operation.
      */
     QEMUIOVector *data_qiov;
+    size_t data_qiov_offset;
 
     /** Pointer to next L2Meta of the same write request */
     struct QCowL2Meta *next;
diff --git a/include/qemu/iov.h b/include/qemu/iov.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/iov.h
+++ b/include/qemu/iov.h
@@ -XXX,XX +XXX,XX @@ void qemu_iovec_init_extended(
         void *tail_buf, size_t tail_len);
 void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source,
                            size_t offset, size_t len);
+int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len);
 void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len);
 void qemu_iovec_concat(QEMUIOVector *dst,
                        QEMUIOVector *src, size_t soffset, size_t sbytes);
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -XXX,XX +XXX,XX @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m)
     assert(start->nb_bytes <= UINT_MAX - end->nb_bytes);
     assert(start->nb_bytes + end->nb_bytes <= UINT_MAX - data_bytes);
     assert(start->offset + start->nb_bytes <= end->offset);
-    assert(!m->data_qiov || m->data_qiov->size == data_bytes);
 
     if ((start->nb_bytes == 0 && end->nb_bytes == 0) || m->skip_cow) {
         return 0;
@@ -XXX,XX +XXX,XX @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m)
     /* The part of the buffer where the end region is located */
     end_buffer = start_buffer + buffer_size - end->nb_bytes;
 
-    qemu_iovec_init(&qiov, 2 + (m->data_qiov ? m->data_qiov->niov : 0));
+    qemu_iovec_init(&qiov, 2 + (m->data_qiov ?
+                                qemu_iovec_subvec_niov(m->data_qiov,
+                                                       m->data_qiov_offset,
+                                                       data_bytes)
+                                : 0));
 
     qemu_co_mutex_unlock(&s->lock);
     /* First we read the existing data from both COW regions. We
@@ -XXX,XX +XXX,XX @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m)
         if (start->nb_bytes) {
             qemu_iovec_add(&qiov, start_buffer, start->nb_bytes);
         }
-        qemu_iovec_concat(&qiov, m->data_qiov, 0, data_bytes);
+        qemu_iovec_concat(&qiov, m->data_qiov, m->data_qiov_offset, data_bytes);
         if (end->nb_bytes) {
             qemu_iovec_add(&qiov, end_buffer, end->nb_bytes);
         }
diff --git a/block/qcow2.c b/block/qcow2.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -XXX,XX +XXX,XX @@ fail:
 /* Check if it's possible to merge a write request with the writing of
  * the data from the COW regions */
 static bool merge_cow(uint64_t offset, unsigned bytes,
-                      QEMUIOVector *hd_qiov, QCowL2Meta *l2meta)
+                      QEMUIOVector *qiov, size_t qiov_offset,
+                      QCowL2Meta *l2meta)
 {
     QCowL2Meta *m;
 
@@ -XXX,XX +XXX,XX @@ static bool merge_cow(uint64_t offset, unsigned bytes,
 
         /* Make sure that adding both COW regions to the QEMUIOVector
          * does not exceed IOV_MAX */
-        if (hd_qiov->niov > IOV_MAX - 2) {
+        if (qemu_iovec_subvec_niov(qiov, qiov_offset, bytes) > IOV_MAX - 2) {
             continue;
         }
 
-        m->data_qiov = hd_qiov;
+        m->data_qiov = qiov;
+        m->data_qiov_offset = qiov_offset;
         return true;
     }
 
@@ -XXX,XX +XXX,XX @@ static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta)
     return 0;
 }
 
-static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
-                                         uint64_t bytes, QEMUIOVector *qiov,
-                                         int flags)
+static coroutine_fn int qcow2_co_pwritev_part(
+        BlockDriverState *bs, uint64_t offset, uint64_t bytes,
+        QEMUIOVector *qiov, size_t qiov_offset, int flags)
 {
     BDRVQcow2State *s = bs->opaque;
     int offset_in_cluster;
     int ret;
     unsigned int cur_bytes; /* number of sectors in current iteration */
     uint64_t cluster_offset;
-    QEMUIOVector hd_qiov;
+    QEMUIOVector encrypted_qiov;
     uint64_t bytes_done = 0;
     uint8_t *cluster_data = NULL;
     QCowL2Meta *l2meta = NULL;
 
     trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes);
 
-    qemu_iovec_init(&hd_qiov, qiov->niov);
-
     qemu_co_mutex_lock(&s->lock);
 
     while (bytes != 0) {
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
 
         qemu_co_mutex_unlock(&s->lock);
 
-        qemu_iovec_reset(&hd_qiov);
-        qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
-
         if (bs->encrypted) {
             assert(s->crypto);
             if (!cluster_data) {
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
                 }
             }
 
-            assert(hd_qiov.size <=
-                   QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
-            qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);
+            assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
+            qemu_iovec_to_buf(qiov, qiov_offset + bytes_done,
+                              cluster_data, cur_bytes);
 
             if (qcow2_co_encrypt(bs, cluster_offset, offset,
                                  cluster_data, cur_bytes) < 0) {
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
                 goto out_unlocked;
             }
 
-            qemu_iovec_reset(&hd_qiov);
-            qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
+            qemu_iovec_init_buf(&encrypted_qiov, cluster_data, cur_bytes);
         }
 
         /* Try to efficiently initialize the physical space with zeroes */
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
          * writing of the guest data together with that of the COW regions.
          * If it's not possible (or not necessary) then write the
          * guest data now. */
-        if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) {
+        if (!merge_cow(offset, cur_bytes,
+                       bs->encrypted ? &encrypted_qiov : qiov,
+                       bs->encrypted ? 0 : qiov_offset + bytes_done, l2meta))
+        {
             BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
             trace_qcow2_writev_data(qemu_coroutine_self(),
                                     cluster_offset + offset_in_cluster);
-            ret = bdrv_co_pwritev(s->data_file,
-                                  cluster_offset + offset_in_cluster,
-                                  cur_bytes, &hd_qiov, 0);
+            ret = bdrv_co_pwritev_part(
+                    s->data_file, cluster_offset + offset_in_cluster, cur_bytes,
+                    bs->encrypted ? &encrypted_qiov : qiov,
+                    bs->encrypted ? 0 : qiov_offset + bytes_done, 0);
             if (ret < 0) {
                 goto out_unlocked;
             }
@@ -XXX,XX +XXX,XX @@ out_locked:
 
     qemu_co_mutex_unlock(&s->lock);
 
-    qemu_iovec_destroy(&hd_qiov);
     qemu_vfree(cluster_data);
     trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
 
@@ -XXX,XX +XXX,XX @@ fail:
 /* XXX: put compressed sectors first, then all the cluster aligned
    tables to avoid losing bytes in alignment */
 static coroutine_fn int
-qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
-                            uint64_t bytes, QEMUIOVector *qiov)
+qcow2_co_pwritev_compressed_part(BlockDriverState *bs,
+                                 uint64_t offset, uint64_t bytes,
+                                 QEMUIOVector *qiov, size_t qiov_offset)
 {
     BDRVQcow2State *s = bs->opaque;
     int ret;
@@ -XXX,XX +XXX,XX @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
         /* Zero-pad last write if image size is not cluster aligned */
         memset(buf + bytes, 0, s->cluster_size - bytes);
     }
-    qemu_iovec_to_buf(qiov, 0, buf, bytes);
+    qemu_iovec_to_buf(qiov, qiov_offset, buf, bytes);
 
     out_buf = g_malloc(s->cluster_size);
 
@@ -XXX,XX +XXX,XX @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
                                 buf, s->cluster_size);
     if (out_len == -ENOMEM) {
         /* could not compress: write normal cluster */
-        ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0);
+        ret = qcow2_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset, 0);
         if (ret < 0) {
             goto fail;
         }
@@ -XXX,XX +XXX,XX @@ static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
     BDRVQcow2State *s = bs->opaque;
 
     BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
-    return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos,
-                                    qiov->size, qiov, 0);
+    return bs->drv->bdrv_co_pwritev_part(bs, qcow2_vm_state_offset(s) + pos,
+                                         qiov->size, qiov, 0, 0);
 }
 
 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
@@ -XXX,XX +XXX,XX @@ BlockDriver bdrv_qcow2 = {
     .bdrv_co_block_status = qcow2_co_block_status,
 
     .bdrv_co_preadv_part    = qcow2_co_preadv_part,
-    .bdrv_co_pwritev        = qcow2_co_pwritev,
+    .bdrv_co_pwritev_part   = qcow2_co_pwritev_part,
     .bdrv_co_flush_to_os    = qcow2_co_flush_to_os,
 
     .bdrv_co_pwrite_zeroes  = qcow2_co_pwrite_zeroes,
@@ -XXX,XX +XXX,XX @@ BlockDriver bdrv_qcow2 = {
     .bdrv_co_copy_range_from = qcow2_co_copy_range_from,
     .bdrv_co_copy_range_to  = qcow2_co_copy_range_to,
     .bdrv_co_truncate       = qcow2_co_truncate,
-    .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed,
+    .bdrv_co_pwritev_compressed_part = qcow2_co_pwritev_compressed_part,
     .bdrv_make_empty        = qcow2_make_empty,
 
     .bdrv_snapshot_create   = qcow2_snapshot_create,
diff --git a/util/iov.c b/util/iov.c
index XXXXXXX..XXXXXXX 100644
--- a/util/iov.c
+++ b/util/iov.c
@@ -XXX,XX +XXX,XX @@ static struct iovec *qiov_slice(QEMUIOVector *qiov,
     return iov;
 }
 
+int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len)
+{
+    size_t head, tail;
+    int niov;
+
+    qiov_slice(qiov, offset, len, &head, &tail, &niov);
+
+    return niov;
+}
+
 /*
  * Compile new iovec, combining @head_buf buffer, sub-qiov of @mid_qiov,
  * and @tail_buf buffer into new qiov.
-- 
2.21.0

The following changes since commit ac793156f650ae2d77834932d72224175ee69086:

Merge remote-tracking branch 'remotes/pmaydell/tags/pull-target-arm-20201020-1' into staging (2020-10-20 21:11:35 +0100)

are available in the Git repository at:

https://gitlab.com/stefanha/qemu.git tags/block-pull-request

for you to fetch changes up to 32a3fd65e7e3551337fd26bfc0e2f899d70c028c:

iotests: add commit top->base cases to 274 (2020-10-22 09:55:39 +0100)

----------------------------------------------------------------
Pull request

v2:
 * Fix format string issues on 32-bit hosts [Peter]
 * Fix qemu-nbd.c CONFIG_POSIX ifdef issue [Eric]
 * Fix missing eventfd.h header on macOS [Peter]
 * Drop unreliable vhost-user-blk test (will send a new patch when ready) [Peter]

This pull request contains the vhost-user-blk server by Coiby Xu along with my
additions, block/nvme.c alignment and hardware error statistics by Philippe
Mathieu-Daudé, and bdrv_co_block_status_above() fixes by Vladimir
Sementsov-Ogievskiy.

----------------------------------------------------------------

Coiby Xu (6):
  libvhost-user: Allow vu_message_read to be replaced
  libvhost-user: remove watch for kick_fd when de-initialize vu-dev
  util/vhost-user-server: generic vhost user server
  block: move logical block size check function to a common utility
    function
  block/export: vhost-user block device backend server
  MAINTAINERS: Add vhost-user block device backend server maintainer

Philippe Mathieu-Daudé (1):
  block/nvme: Add driver statistics for access alignment and hw errors

Stefan Hajnoczi (16):
  util/vhost-user-server: s/fileds/fields/ typo fix
  util/vhost-user-server: drop unnecessary QOM cast
  util/vhost-user-server: drop unnecessary watch deletion
  block/export: consolidate request structs into VuBlockReq
  util/vhost-user-server: drop unused DevicePanicNotifier
  util/vhost-user-server: fix memory leak in vu_message_read()
  util/vhost-user-server: check EOF when reading payload
  util/vhost-user-server: rework vu_client_trip() coroutine lifecycle
  block/export: report flush errors
  block/export: convert vhost-user-blk server to block export API
  util/vhost-user-server: move header to include/
  util/vhost-user-server: use static library in meson.build
  qemu-storage-daemon: avoid compiling blockdev_ss twice
  block: move block exports to libblockdev
  block/export: add iothread and fixed-iothread options
  block/export: add vhost-user-blk multi-queue support

Vladimir Sementsov-Ogievskiy (5):
  block/io: fix bdrv_co_block_status_above
  block/io: bdrv_common_block_status_above: support include_base
  block/io: bdrv_common_block_status_above: support bs == base
  block/io: fix bdrv_is_allocated_above
  iotests: add commit top->base cases to 274

-- 
2.26.2

From: Philippe Mathieu-Daudé <philmd@redhat.com>

Keep statistics of some hardware errors, and number of
aligned/unaligned I/O accesses.

QMP example booting a full RHEL 8.3 aarch64 guest:

{ "execute": "query-blockstats" }
{
    "return": [
        {
            "device": "",
            "node-name": "drive0",
            "stats": {
                "flush_total_time_ns": 6026948,
                "wr_highest_offset": 3383991230464,
                "wr_total_time_ns": 807450995,
                "failed_wr_operations": 0,
                "failed_rd_operations": 0,
                "wr_merged": 3,
                "wr_bytes": 50133504,
                "failed_unmap_operations": 0,
                "failed_flush_operations": 0,
                "account_invalid": false,
                "rd_total_time_ns": 1846979900,
                "flush_operations": 130,
                "wr_operations": 659,
                "rd_merged": 1192,
                "rd_bytes": 218244096,
                "account_failed": false,
                "idle_time_ns": 2678641497,
                "rd_operations": 7406,
            },
            "driver-specific": {
                "driver": "nvme",
                "completion-errors": 0,
                "unaligned-accesses": 2959,
                "aligned-accesses": 4477
            },
            "qdev": "/machine/peripheral-anon/device[0]/virtio-backend"
        }
    ]
}

Suggested-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20201001162939.1567915-1-philmd@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 qapi/block-core.json | 24 +++++++++++++++++++++++-
 block/nvme.c         | 27 +++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/qapi/block-core.json b/qapi/block-core.json
index XXXXXXX..XXXXXXX 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -XXX,XX +XXX,XX @@
       'discard-nb-failed': 'uint64',
       'discard-bytes-ok': 'uint64' } }
 
+##
+# @BlockStatsSpecificNvme:
+#
+# NVMe driver statistics
+#
+# @completion-errors: The number of completion errors.
+#
+# @aligned-accesses: The number of aligned accesses performed by
+#                    the driver.
+#
+# @unaligned-accesses: The number of unaligned accesses performed by
+#                      the driver.
+#
+# Since: 5.2
+##
+{ 'struct': 'BlockStatsSpecificNvme',
+  'data': {
+      'completion-errors': 'uint64',
+      'aligned-accesses': 'uint64',
+      'unaligned-accesses': 'uint64' } }
+
 ##
 # @BlockStatsSpecific:
 #
@@ -XXX,XX +XXX,XX @@
   'discriminator': 'driver',
   'data': {
       'file': 'BlockStatsSpecificFile',
-      'host_device': 'BlockStatsSpecificFile' } }
+      'host_device': 'BlockStatsSpecificFile',
+      'nvme': 'BlockStatsSpecificNvme' } }
 
 ##
 # @BlockStats:
diff --git a/block/nvme.c b/block/nvme.c
index XXXXXXX..XXXXXXX 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -XXX,XX +XXX,XX @@ struct BDRVNVMeState {
 
     /* PCI address (required for nvme_refresh_filename()) */
     char *device;
+
+    struct {
+        uint64_t completion_errors;
+        uint64_t aligned_accesses;
+        uint64_t unaligned_accesses;
+    } stats;
 };
 
 #define NVME_BLOCK_OPT_DEVICE "device"
@@ -XXX,XX +XXX,XX @@ static bool nvme_process_completion(NVMeQueuePair *q)
             break;
         }
         ret = nvme_translate_error(c);
+        if (ret) {
+            s->stats.completion_errors++;
+        }
         q->cq.head = (q->cq.head + 1) % NVME_QUEUE_SIZE;
         if (!q->cq.head) {
             q->cq_phase = !q->cq_phase;
@@ -XXX,XX +XXX,XX @@ static int nvme_co_prw(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
     assert(QEMU_IS_ALIGNED(bytes, s->page_size));
     assert(bytes <= s->max_transfer);
     if (nvme_qiov_aligned(bs, qiov)) {
+        s->stats.aligned_accesses++;
         return nvme_co_prw_aligned(bs, offset, bytes, qiov, is_write, flags);
     }
+    s->stats.unaligned_accesses++;
     trace_nvme_prw_buffered(s, offset, bytes, qiov->niov, is_write);
     buf = qemu_try_memalign(s->page_size, bytes);
 
@@ -XXX,XX +XXX,XX @@ static void nvme_unregister_buf(BlockDriverState *bs, void *host)
     qemu_vfio_dma_unmap(s->vfio, host);
 }
 
+static BlockStatsSpecific *nvme_get_specific_stats(BlockDriverState *bs)
+{
+    BlockStatsSpecific *stats = g_new(BlockStatsSpecific, 1);
+    BDRVNVMeState *s = bs->opaque;
+
+    stats->driver = BLOCKDEV_DRIVER_NVME;
+    stats->u.nvme = (BlockStatsSpecificNvme) {
+        .completion_errors = s->stats.completion_errors,
+        .aligned_accesses = s->stats.aligned_accesses,
+        .unaligned_accesses = s->stats.unaligned_accesses,
+    };
+
+    return stats;
+}
+
 static const char *const nvme_strong_runtime_opts[] = {
     NVME_BLOCK_OPT_DEVICE,
     NVME_BLOCK_OPT_NAMESPACE,
@@ -XXX,XX +XXX,XX @@ static BlockDriver bdrv_nvme = {
     .bdrv_refresh_filename    = nvme_refresh_filename,
     .bdrv_refresh_limits      = nvme_refresh_limits,
     .strong_runtime_opts      = nvme_strong_runtime_opts,
+    .bdrv_get_specific_stats  = nvme_get_specific_stats,
 
     .bdrv_detach_aio_context  = nvme_detach_aio_context,
     .bdrv_attach_aio_context  = nvme_attach_aio_context,
-- 
2.26.2

From: Coiby Xu <coiby.xu@gmail.com>

Allow vu_message_read to be replaced by one which will make use of the
QIOChannel functions. Thus reading vhost-user message won't stall the
guest. For slave channel, we still use the default vu_message_read.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200918080912.321299-2-coiby.xu@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 contrib/libvhost-user/libvhost-user.h      | 21 +++++++++++++++++++++
 contrib/libvhost-user/libvhost-user-glib.c |  2 +-
 contrib/libvhost-user/libvhost-user.c      | 14 +++++++-------
 tests/vhost-user-bridge.c                  |  2 ++
 tools/virtiofsd/fuse_virtio.c              |  4 ++--
 5 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h
index XXXXXXX..XXXXXXX 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -XXX,XX +XXX,XX @@
  */
 #define VHOST_USER_MAX_RAM_SLOTS 32
 
+#define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
+
 typedef enum VhostSetConfigType {
     VHOST_SET_CONFIG_TYPE_MASTER = 0,
     VHOST_SET_CONFIG_TYPE_MIGRATION = 1,
@@ -XXX,XX +XXX,XX @@ typedef uint64_t (*vu_get_features_cb) (VuDev *dev);
 typedef void (*vu_set_features_cb) (VuDev *dev, uint64_t features);
 typedef int (*vu_process_msg_cb) (VuDev *dev, VhostUserMsg *vmsg,
                                   int *do_reply);
+typedef bool (*vu_read_msg_cb) (VuDev *dev, int sock, VhostUserMsg *vmsg);
 typedef void (*vu_queue_set_started_cb) (VuDev *dev, int qidx, bool started);
 typedef bool (*vu_queue_is_processed_in_order_cb) (VuDev *dev, int qidx);
 typedef int (*vu_get_config_cb) (VuDev *dev, uint8_t *config, uint32_t len);
@@ -XXX,XX +XXX,XX @@ struct VuDev {
     bool broken;
     uint16_t max_queues;
 
+    /* @read_msg: custom method to read vhost-user message
+     *
+     * Read data from vhost_user socket fd and fill up
+     * the passed VhostUserMsg *vmsg struct.
+     *
+     * If reading fails, it should close the received set of file
+     * descriptors as socket message's auxiliary data.
+     *
+     * For the details, please refer to vu_message_read in libvhost-user.c
+     * which will be used by default if not custom method is provided when
+     * calling vu_init
+     *
+     * Returns: true if vhost-user message successfully received,
+     *          otherwise return false.
+     *
+     */
+    vu_read_msg_cb read_msg;
     /* @set_watch: add or update the given fd to the watch set,
      * call cb when condition is met */
     vu_set_watch_cb set_watch;
@@ -XXX,XX +XXX,XX @@ bool vu_init(VuDev *dev,
              uint16_t max_queues,
              int socket,
              vu_panic_cb panic,
+             vu_read_msg_cb read_msg,
              vu_set_watch_cb set_watch,
              vu_remove_watch_cb remove_watch,
              const VuDevIface *iface);
diff --git a/contrib/libvhost-user/libvhost-user-glib.c b/contrib/libvhost-user/libvhost-user-glib.c
index XXXXXXX..XXXXXXX 100644
--- a/contrib/libvhost-user/libvhost-user-glib.c
+++ b/contrib/libvhost-user/libvhost-user-glib.c
@@ -XXX,XX +XXX,XX @@ vug_init(VugDev *dev, uint16_t max_queues, int socket,
     g_assert(dev);
     g_assert(iface);
 
-    if (!vu_init(&dev->parent, max_queues, socket, panic, set_watch,
+    if (!vu_init(&dev->parent, max_queues, socket, panic, NULL, set_watch,
                  remove_watch, iface)) {
         return false;
     }
diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
index XXXXXXX..XXXXXXX 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -XXX,XX +XXX,XX @@
 /* The version of inflight buffer */
 #define INFLIGHT_VERSION 1
 
-#define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
-
 /* The version of the protocol we support */
 #define VHOST_USER_VERSION 1
 #define LIBVHOST_USER_DEBUG 0
@@ -XXX,XX +XXX,XX @@ have_userfault(void)
 }
 
 static bool
-vu_message_read(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
+vu_message_read_default(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
 {
     char control[CMSG_SPACE(VHOST_MEMORY_BASELINE_NREGIONS * sizeof(int))] = {};
     struct iovec iov = {
@@ -XXX,XX +XXX,XX @@ vu_process_message_reply(VuDev *dev, const VhostUserMsg *vmsg)
         goto out;
     }
 
-    if (!vu_message_read(dev, dev->slave_fd, &msg_reply)) {
+    if (!vu_message_read_default(dev, dev->slave_fd, &msg_reply)) {
         goto out;
     }
 
@@ -XXX,XX +XXX,XX @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
     /* Wait for QEMU to confirm that it's registered the handler for the
      * faults.
      */
-    if (!vu_message_read(dev, dev->sock, vmsg) ||
+    if (!dev->read_msg(dev, dev->sock, vmsg) ||
         vmsg->size != sizeof(vmsg->payload.u64) ||
         vmsg->payload.u64 != 0) {
         vu_panic(dev, "failed to receive valid ack for postcopy set-mem-table");
@@ -XXX,XX +XXX,XX @@ vu_dispatch(VuDev *dev)
     int reply_requested;
     bool need_reply, success = false;
 
-    if (!vu_message_read(dev, dev->sock, &vmsg)) {
+    if (!dev->read_msg(dev, dev->sock, &vmsg)) {
         goto end;
     }
 
@@ -XXX,XX +XXX,XX @@ vu_init(VuDev *dev,
         uint16_t max_queues,
         int socket,
         vu_panic_cb panic,
+        vu_read_msg_cb read_msg,
         vu_set_watch_cb set_watch,
         vu_remove_watch_cb remove_watch,
         const VuDevIface *iface)
@@ -XXX,XX +XXX,XX @@ vu_init(VuDev *dev,
 
     dev->sock = socket;
     dev->panic = panic;
+    dev->read_msg = read_msg ? read_msg : vu_message_read_default;
     dev->set_watch = set_watch;
     dev->remove_watch = remove_watch;
     dev->iface = iface;
@@ -XXX,XX +XXX,XX @@ static void _vu_queue_notify(VuDev *dev, VuVirtq *vq, bool sync)
 
         vu_message_write(dev, dev->slave_fd, &vmsg);
         if (ack) {
-            vu_message_read(dev, dev->slave_fd, &vmsg);
+            vu_message_read_default(dev, dev->slave_fd, &vmsg);
         }
         return;
     }
diff --git a/tests/vhost-user-bridge.c b/tests/vhost-user-bridge.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/vhost-user-bridge.c
+++ b/tests/vhost-user-bridge.c
@@ -XXX,XX +XXX,XX @@ vubr_accept_cb(int sock, void *ctx)
                  VHOST_USER_BRIDGE_MAX_QUEUES,
                  conn_fd,
                  vubr_panic,
+                 NULL,
                  vubr_set_watch,
                  vubr_remove_watch,
                  &vuiface)) {
@@ -XXX,XX +XXX,XX @@ vubr_new(const char *path, bool client)
                      VHOST_USER_BRIDGE_MAX_QUEUES,
                      dev->sock,
                      vubr_panic,
+                     NULL,
                      vubr_set_watch,
                      vubr_remove_watch,
                      &vuiface)) {
diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index XXXXXXX..XXXXXXX 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -XXX,XX +XXX,XX @@ int virtio_session_mount(struct fuse_session *se)
     se->vu_socketfd = data_sock;
     se->virtio_dev->se = se;
     pthread_rwlock_init(&se->virtio_dev->vu_dispatch_rwlock, NULL);
-    vu_init(&se->virtio_dev->dev, 2, se->vu_socketfd, fv_panic, fv_set_watch,
-            fv_remove_watch, &fv_iface);
+    vu_init(&se->virtio_dev->dev, 2, se->vu_socketfd, fv_panic, NULL,
+            fv_set_watch, fv_remove_watch, &fv_iface);
 
     return 0;
 }
-- 
2.26.2

From: Coiby Xu <coiby.xu@gmail.com>

Sharing QEMU devices via vhost-user protocol.

Only one vhost-user client can connect to the server one time.

diff --git a/util/vhost-user-server.h b/util/vhost-user-server.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/util/vhost-user-server.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * Sharing QEMU devices via vhost-user protocol
+ *
+ * Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
+ * Copyright (c) 2020 Red Hat, Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+
+#ifndef VHOST_USER_SERVER_H
+#define VHOST_USER_SERVER_H
+
+#include "contrib/libvhost-user/libvhost-user.h"
+#include "io/channel-socket.h"
+#include "io/channel-file.h"
+#include "io/net-listener.h"
+#include "qemu/error-report.h"
+#include "qapi/error.h"
+#include "standard-headers/linux/virtio_blk.h"
+
+typedef struct VuFdWatch {
+    VuDev *vu_dev;
+    int fd; /*kick fd*/
+    void *pvt;
+    vu_watch_cb cb;
+    bool processing;
+    QTAILQ_ENTRY(VuFdWatch) next;
+} VuFdWatch;
+
+typedef struct VuServer VuServer;
+typedef void DevicePanicNotifierFn(VuServer *server);
+
+struct VuServer {
+    QIONetListener *listener;
+    AioContext *ctx;
+    DevicePanicNotifierFn *device_panic_notifier;
+    int max_queues;
+    const VuDevIface *vu_iface;
+    VuDev vu_dev;
+    QIOChannel *ioc; /* The I/O channel with the client */
+    QIOChannelSocket *sioc; /* The underlying data channel with the client */
+    /* IOChannel for fd provided via VHOST_USER_SET_SLAVE_REQ_FD */
+    QIOChannel *ioc_slave;
+    QIOChannelSocket *sioc_slave;
+    Coroutine *co_trip; /* coroutine for processing VhostUserMsg */
+    QTAILQ_HEAD(, VuFdWatch) vu_fd_watches;
+    /* restart coroutine co_trip if AIOContext is changed */
+    bool aio_context_changed;
+    bool processing_msg;
+};
+
+bool vhost_user_server_start(VuServer *server,
+                             SocketAddress *unix_socket,
+                             AioContext *ctx,
+                             uint16_t max_queues,
+                             DevicePanicNotifierFn *device_panic_notifier,
+                             const VuDevIface *vu_iface,
+                             Error **errp);
+
+void vhost_user_server_stop(VuServer *server);
+
+void vhost_user_server_set_aio_context(VuServer *server, AioContext *ctx);
+
+#endif /* VHOST_USER_SERVER_H */
diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/util/vhost-user-server.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Sharing QEMU devices via vhost-user protocol
+ *
+ * Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
+ * Copyright (c) 2020 Red Hat, Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+#include "qemu/osdep.h"
+#include "qemu/main-loop.h"
+#include "vhost-user-server.h"
+
+static void vmsg_close_fds(VhostUserMsg *vmsg)
+{
+    int i;
+    for (i = 0; i < vmsg->fd_num; i++) {
+        close(vmsg->fds[i]);
+    }
+}
+
+static void vmsg_unblock_fds(VhostUserMsg *vmsg)
+{
+    int i;
+    for (i = 0; i < vmsg->fd_num; i++) {
+        qemu_set_nonblock(vmsg->fds[i]);
+    }
+}
+
+static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
+                      gpointer opaque);
+
+static void close_client(VuServer *server)
+{
+    /*
+     * Before closing the client
+     *
+     * 1. Let vu_client_trip stop processing new vhost-user msg
+     *
+     * 2. remove kick_handler
+     *
+     * 3. wait for the kick handler to be finished
+     *
+     * 4. wait for the current vhost-user msg to be finished processing
+     */
+
+    QIOChannelSocket *sioc = server->sioc;
+    /* When this is set vu_client_trip will stop new processing vhost-user message */
+    server->sioc = NULL;
+
+    VuFdWatch *vu_fd_watch, *next;
+    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
+        aio_set_fd_handler(server->ioc->ctx, vu_fd_watch->fd, true, NULL,
+                           NULL, NULL, NULL);
+    }
+
+    while (!QTAILQ_EMPTY(&server->vu_fd_watches)) {
+        QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
+            if (!vu_fd_watch->processing) {
+                QTAILQ_REMOVE(&server->vu_fd_watches, vu_fd_watch, next);
+                g_free(vu_fd_watch);
+            }
+        }
+    }
+
+    while (server->processing_msg) {
+        if (server->ioc->read_coroutine) {
+            server->ioc->read_coroutine = NULL;
+            qio_channel_set_aio_fd_handler(server->ioc, server->ioc->ctx, NULL,
+                                           NULL, server->ioc);
+            server->processing_msg = false;
+        }
+    }
+
+    vu_deinit(&server->vu_dev);
+    object_unref(OBJECT(sioc));
+    object_unref(OBJECT(server->ioc));
+}
+
+static void panic_cb(VuDev *vu_dev, const char *buf)
+{
+    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+
+    /* avoid while loop in close_client */
+    server->processing_msg = false;
+
+    if (buf) {
+        error_report("vu_panic: %s", buf);
+    }
+
+    if (server->sioc) {
+        close_client(server);
+    }
+
+    if (server->device_panic_notifier) {
+        server->device_panic_notifier(server);
+    }
+
+    /*
+     * Set the callback function for network listener so another
+     * vhost-user client can connect to this server
+     */
+    qio_net_listener_set_client_func(server->listener,
+                                     vu_accept,
+                                     server,
+                                     NULL);
+}
+
+static bool coroutine_fn
+vu_message_read(VuDev *vu_dev, int conn_fd, VhostUserMsg *vmsg)
+{
+    struct iovec iov = {
+        .iov_base = (char *)vmsg,
+        .iov_len = VHOST_USER_HDR_SIZE,
+    };
+    int rc, read_bytes = 0;
+    Error *local_err = NULL;
+    /*
+     * Store fds/nfds returned from qio_channel_readv_full into
+     * temporary variables.
+     *
+     * VhostUserMsg is a packed structure, gcc will complain about passing
+     * pointer to a packed structure member if we pass &VhostUserMsg.fd_num
+     * and &VhostUserMsg.fds directly when calling qio_channel_readv_full,
+     * thus two temporary variables nfds and fds are used here.
+     */
+    size_t nfds = 0, nfds_t = 0;
+    const size_t max_fds = G_N_ELEMENTS(vmsg->fds);
+    int *fds_t = NULL;
+    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+    QIOChannel *ioc = server->ioc;
+
+    if (!ioc) {
+        error_report_err(local_err);
+        goto fail;
+    }
+
+    assert(qemu_in_coroutine());
+    do {
+        /*
+         * qio_channel_readv_full may have short reads, keeping calling it
+         * until getting VHOST_USER_HDR_SIZE or 0 bytes in total
+         */
+        rc = qio_channel_readv_full(ioc, &iov, 1, &fds_t, &nfds_t, &local_err);
+        if (rc < 0) {
+            if (rc == QIO_CHANNEL_ERR_BLOCK) {
+                qio_channel_yield(ioc, G_IO_IN);
+                continue;
+            } else {
+                error_report_err(local_err);
+                return false;
+            }
+        }
+        read_bytes += rc;
+        if (nfds_t > 0) {
+            if (nfds + nfds_t > max_fds) {
+                error_report("A maximum of %zu fds are allowed, "
+                             "however got %zu fds now",
+                             max_fds, nfds + nfds_t);
+                goto fail;
+            }
+            memcpy(vmsg->fds + nfds, fds_t,
+                   nfds_t *sizeof(vmsg->fds[0]));
+            nfds += nfds_t;
+            g_free(fds_t);
+        }
+        if (read_bytes == VHOST_USER_HDR_SIZE || rc == 0) {
+            break;
+        }
+        iov.iov_base = (char *)vmsg + read_bytes;
+        iov.iov_len = VHOST_USER_HDR_SIZE - read_bytes;
+    } while (true);
+
+    vmsg->fd_num = nfds;
+    /* qio_channel_readv_full will make socket fds blocking, unblock them */
+    vmsg_unblock_fds(vmsg);
+    if (vmsg->size > sizeof(vmsg->payload)) {
+        error_report("Error: too big message request: %d, "
+                     "size: vmsg->size: %u, "
+                     "while sizeof(vmsg->payload) = %zu",
+                     vmsg->request, vmsg->size, sizeof(vmsg->payload));
+        goto fail;
+    }
+
+    struct iovec iov_payload = {
+        .iov_base = (char *)&vmsg->payload,
+        .iov_len = vmsg->size,
+    };
+    if (vmsg->size) {
+        rc = qio_channel_readv_all_eof(ioc, &iov_payload, 1, &local_err);
+        if (rc == -1) {
+            error_report_err(local_err);
+            goto fail;
+        }
+    }
+
+    return true;
+
+fail:
+    vmsg_close_fds(vmsg);
+
+    return false;
+}
+
+
+static void vu_client_start(VuServer *server);
+static coroutine_fn void vu_client_trip(void *opaque)
+{
+    VuServer *server = opaque;
+
+    while (!server->aio_context_changed && server->sioc) {
+        server->processing_msg = true;
+        vu_dispatch(&server->vu_dev);
+        server->processing_msg = false;
+    }
+
+    if (server->aio_context_changed && server->sioc) {
+        server->aio_context_changed = false;
+        vu_client_start(server);
+    }
+}
+
+static void vu_client_start(VuServer *server)
+{
+    server->co_trip = qemu_coroutine_create(vu_client_trip, server);
+    aio_co_enter(server->ctx, server->co_trip);
+}
+
+/*
+ * a wrapper for vu_kick_cb
+ *
+ * since aio_dispatch can only pass one user data pointer to the
+ * callback function, pack VuDev and pvt into a struct. Then unpack it
+ * and pass them to vu_kick_cb
+ */
+static void kick_handler(void *opaque)
+{
+    VuFdWatch *vu_fd_watch = opaque;
+    vu_fd_watch->processing = true;
+    vu_fd_watch->cb(vu_fd_watch->vu_dev, 0, vu_fd_watch->pvt);
+    vu_fd_watch->processing = false;
+}
+
+
+static VuFdWatch *find_vu_fd_watch(VuServer *server, int fd)
+{
+
+    VuFdWatch *vu_fd_watch, *next;
+    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
+        if (vu_fd_watch->fd == fd) {
+            return vu_fd_watch;
+        }
+    }
+    return NULL;
+}
+
+static void
+set_watch(VuDev *vu_dev, int fd, int vu_evt,
+          vu_watch_cb cb, void *pvt)
+{
+
+    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+    g_assert(vu_dev);
+    g_assert(fd >= 0);
+    g_assert(cb);
+
+    VuFdWatch *vu_fd_watch = find_vu_fd_watch(server, fd);
+
+    if (!vu_fd_watch) {
+        VuFdWatch *vu_fd_watch = g_new0(VuFdWatch, 1);
+
+        QTAILQ_INSERT_TAIL(&server->vu_fd_watches, vu_fd_watch, next);
+
+        vu_fd_watch->fd = fd;
+        vu_fd_watch->cb = cb;
+        qemu_set_nonblock(fd);
+        aio_set_fd_handler(server->ioc->ctx, fd, true, kick_handler,
+                           NULL, NULL, vu_fd_watch);
+        vu_fd_watch->vu_dev = vu_dev;
+        vu_fd_watch->pvt = pvt;
+    }
+}
+
+
+static void remove_watch(VuDev *vu_dev, int fd)
+{
+    VuServer *server;
+    g_assert(vu_dev);
+    g_assert(fd >= 0);
+
+    server = container_of(vu_dev, VuServer, vu_dev);
+
+    VuFdWatch *vu_fd_watch = find_vu_fd_watch(server, fd);
+
+    if (!vu_fd_watch) {
+        return;
+    }
+    aio_set_fd_handler(server->ioc->ctx, fd, true, NULL, NULL, NULL, NULL);
+
+    QTAILQ_REMOVE(&server->vu_fd_watches, vu_fd_watch, next);
+    g_free(vu_fd_watch);
+}
+
+
+static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
+                      gpointer opaque)
+{
+    VuServer *server = opaque;
+
+    if (server->sioc) {
+        warn_report("Only one vhost-user client is allowed to "
+                    "connect the server one time");
+        return;
+    }
+
+    if (!vu_init(&server->vu_dev, server->max_queues, sioc->fd, panic_cb,
+                 vu_message_read, set_watch, remove_watch, server->vu_iface)) {
+        error_report("Failed to initialize libvhost-user");
+        return;
+    }
+
+    /*
+     * Unset the callback function for network listener to make another
+     * vhost-user client keeping waiting until this client disconnects
+     */
+    qio_net_listener_set_client_func(server->listener,
+                                     NULL,
+                                     NULL,
+                                     NULL);
+    server->sioc = sioc;
+    /*
+     * Increase the object reference, so sioc will not freed by
+     * qio_net_listener_channel_func which will call object_unref(OBJECT(sioc))
+     */
+    object_ref(OBJECT(server->sioc));
+    qio_channel_set_name(QIO_CHANNEL(sioc), "vhost-user client");
+    server->ioc = QIO_CHANNEL(sioc);
+    object_ref(OBJECT(server->ioc));
+    qio_channel_attach_aio_context(server->ioc, server->ctx);
+    qio_channel_set_blocking(QIO_CHANNEL(server->sioc), false, NULL);
+    vu_client_start(server);
+}
+
+
+void vhost_user_server_stop(VuServer *server)
+{
+    if (server->sioc) {
+        close_client(server);
+    }
+
+    if (server->listener) {
+        qio_net_listener_disconnect(server->listener);
+        object_unref(OBJECT(server->listener));
+    }
+
+}
+
+void vhost_user_server_set_aio_context(VuServer *server, AioContext *ctx)
+{
+    VuFdWatch *vu_fd_watch, *next;
+    void *opaque = NULL;
+    IOHandler *io_read = NULL;
+    bool attach;
+
+    server->ctx = ctx ? ctx : qemu_get_aio_context();
+
+    if (!server->sioc) {
+        /* not yet serving any client*/
+        return;
+    }
+
+    if (ctx) {
+        qio_channel_attach_aio_context(server->ioc, ctx);
+        server->aio_context_changed = true;
+        io_read = kick_handler;
+        attach = true;
+    } else {
+        qio_channel_detach_aio_context(server->ioc);
+        /* server->ioc->ctx keeps the old AioConext */
+        ctx = server->ioc->ctx;
+        attach = false;
+    }
+
+    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
+        if (vu_fd_watch->cb) {
+            opaque = attach ? vu_fd_watch : NULL;
+            aio_set_fd_handler(ctx, vu_fd_watch->fd, true,
+                               io_read, NULL, NULL,
+                               opaque);
+        }
+    }
+}
+
+
+bool vhost_user_server_start(VuServer *server,
+                             SocketAddress *socket_addr,
+                             AioContext *ctx,
+                             uint16_t max_queues,
+                             DevicePanicNotifierFn *device_panic_notifier,
+                             const VuDevIface *vu_iface,
+                             Error **errp)
+{
+    QIONetListener *listener = qio_net_listener_new();
+    if (qio_net_listener_open_sync(listener, socket_addr, 1,
+                                   errp) < 0) {
+        object_unref(OBJECT(listener));
+        return false;
+    }
+
+    /* zero out unspecified fileds */
+    *server = (VuServer) {
+        .listener              = listener,
+        .vu_iface              = vu_iface,
+        .max_queues            = max_queues,
+        .ctx                   = ctx,
+        .device_panic_notifier = device_panic_notifier,
+    };
+
+    qio_net_listener_set_name(server->listener, "vhost-user-backend-listener");
+
+    qio_net_listener_set_client_func(server->listener,
+                                     vu_accept,
+                                     server,
+                                     NULL);
+
+    QTAILQ_INIT(&server->vu_fd_watches);
+    return true;
+}
diff --git a/util/meson.build b/util/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/util/meson.build
+++ b/util/meson.build
@@ -XXX,XX +XXX,XX @@ if have_block
   util_ss.add(files('main-loop.c'))
   util_ss.add(files('nvdimm-utils.c'))
   util_ss.add(files('qemu-coroutine.c', 'qemu-coroutine-lock.c', 'qemu-coroutine-io.c'))
+  util_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-server.c'))
   util_ss.add(files('qemu-coroutine-sleep.c'))
   util_ss.add(files('qemu-co-shared-resource.c'))
   util_ss.add(files('thread-pool.c', 'qemu-timer.c'))
-- 
2.26.2

From: Coiby Xu <coiby.xu@gmail.com>

Move the constants from hw/core/qdev-properties.c to
util/block-helpers.h so that knowledge of the min/max values is

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Message-id: 20200918080912.321299-5-coiby.xu@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 util/block-helpers.h             | 19 +++++++++++++
 hw/core/qdev-properties-system.c | 31 ++++-----------------
 util/block-helpers.c             | 46 ++++++++++++++++++++++++++++++++
 util/meson.build                 |  1 +
 4 files changed, 71 insertions(+), 26 deletions(-)
 create mode 100644 util/block-helpers.h
 create mode 100644 util/block-helpers.c

diff --git a/util/block-helpers.h b/util/block-helpers.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/util/block-helpers.h
@@ -XXX,XX +XXX,XX @@
+#ifndef BLOCK_HELPERS_H
+#define BLOCK_HELPERS_H
+
+#include "qemu/units.h"
+
+/* lower limit is sector size */
+#define MIN_BLOCK_SIZE          INT64_C(512)
+#define MIN_BLOCK_SIZE_STR      "512 B"
+/*
+ * upper limit is arbitrary, 2 MiB looks sufficient for all sensible uses, and
+ * matches qcow2 cluster size limit
+ */
+#define MAX_BLOCK_SIZE          (2 * MiB)
+#define MAX_BLOCK_SIZE_STR      "2 MiB"
+
+void check_block_size(const char *id, const char *name, int64_t value,
+                      Error **errp);
+
+#endif /* BLOCK_HELPERS_H */
diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -XXX,XX +XXX,XX @@
 #include "sysemu/blockdev.h"
 #include "net/net.h"
 #include "hw/pci/pci.h"
+#include "util/block-helpers.h"
 
 static bool check_prop_still_unset(DeviceState *dev, const char *name,
                                    const void *old_val, const char *new_val,
@@ -XXX,XX +XXX,XX @@ const PropertyInfo qdev_prop_losttickpolicy = {
 
 /* --- blocksize --- */
 
-/* lower limit is sector size */
-#define MIN_BLOCK_SIZE          512
-#define MIN_BLOCK_SIZE_STR      "512 B"
-/*
- * upper limit is arbitrary, 2 MiB looks sufficient for all sensible uses, and
- * matches qcow2 cluster size limit
- */
-#define MAX_BLOCK_SIZE          (2 * MiB)
-#define MAX_BLOCK_SIZE_STR      "2 MiB"
-
 static void set_blocksize(Object *obj, Visitor *v, const char *name,
                           void *opaque, Error **errp)
 {
@@ -XXX,XX +XXX,XX @@ static void set_blocksize(Object *obj, Visitor *v, const char *name,
     Property *prop = opaque;
     uint32_t *ptr = qdev_get_prop_ptr(dev, prop);
     uint64_t value;
+    Error *local_err = NULL;
 
     if (dev->realized) {
         qdev_prop_set_after_realize(dev, name, errp);
@@ -XXX,XX +XXX,XX @@ static void set_blocksize(Object *obj, Visitor *v, const char *name,
     if (!visit_type_size(v, name, &value, errp)) {
         return;
     }
-    /* value of 0 means "unset" */
-    if (value && (value < MIN_BLOCK_SIZE || value > MAX_BLOCK_SIZE)) {
-        error_setg(errp,
-                   "Property %s.%s doesn't take value %" PRIu64
-                   " (minimum: " MIN_BLOCK_SIZE_STR
-                   ", maximum: " MAX_BLOCK_SIZE_STR ")",
-                   dev->id ? : "", name, value);
+    check_block_size(dev->id ? : "", name, value, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
         return;
     }
-
-    /* We rely on power-of-2 blocksizes for bitmasks */
-    if ((value & (value - 1)) != 0) {
-        error_setg(errp,
-                  "Property %s.%s doesn't take value '%" PRId64 "', "
-                  "it's not a power of 2", dev->id ?: "", name, (int64_t)value);
-        return;
-    }
-
     *ptr = value;
 }
 
diff --git a/util/block-helpers.c b/util/block-helpers.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/util/block-helpers.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Block utility functions
+ *
+ * Copyright IBM, Corp. 2011
+ * Copyright (c) 2020 Coiby Xu <coiby.xu@gmail.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qerror.h"
+#include "block-helpers.h"
+
+/**
+ * check_block_size:
+ * @id: The unique ID of the object
+ * @name: The name of the property being validated
+ * @value: The block size in bytes
+ * @errp: A pointer to an area to store an error
+ *
+ * This function checks that the block size meets the following conditions:
+ * 1. At least MIN_BLOCK_SIZE
+ * 2. No larger than MAX_BLOCK_SIZE
+ * 3. A power of 2
+ */
+void check_block_size(const char *id, const char *name, int64_t value,
+                      Error **errp)
+{
+    /* value of 0 means "unset" */
+    if (value && (value < MIN_BLOCK_SIZE || value > MAX_BLOCK_SIZE)) {
+        error_setg(errp, QERR_PROPERTY_VALUE_OUT_OF_RANGE,
+                   id, name, value, MIN_BLOCK_SIZE, MAX_BLOCK_SIZE);
+        return;
+    }
+
+    /* We rely on power-of-2 blocksizes for bitmasks */
+    if ((value & (value - 1)) != 0) {
+        error_setg(errp,
+                   "Property %s.%s doesn't take value '%" PRId64
+                   "', it's not a power of 2",
+                   id, name, value);
+        return;
+    }
+}
diff --git a/util/meson.build b/util/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/util/meson.build
+++ b/util/meson.build
@@ -XXX,XX +XXX,XX @@ if have_block
   util_ss.add(files('nvdimm-utils.c'))
   util_ss.add(files('qemu-coroutine.c', 'qemu-coroutine-lock.c', 'qemu-coroutine-io.c'))
   util_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-server.c'))
+  util_ss.add(files('block-helpers.c'))
   util_ss.add(files('qemu-coroutine-sleep.c'))
   util_ss.add(files('qemu-co-shared-resource.c'))
   util_ss.add(files('thread-pool.c', 'qemu-timer.c'))
-- 
2.26.2

From: Coiby Xu <coiby.xu@gmail.com>

By making use of libvhost-user, block device drive can be shared to
the connected vhost-user client. Only one client can connect to the
server one time.

Since vhost-user-server needs a block drive to be created first, delay
the creation of this object.

Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20200918080912.321299-6-coiby.xu@gmail.com
[Shorten "vhost_user_blk_server" string to "vhost_user_blk" to avoid the
following compiler warning:
../block/export/vhost-user-blk-server.c:178:50: error: ‘%s’ directive output truncated writing 21 bytes into a region of size 20 [-Werror=format-truncation=]
and fix "Invalid size %ld ..." ssize_t format string arguments for
32-bit hosts.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/export/vhost-user-blk-server.h |  36 ++
 block/export/vhost-user-blk-server.c | 661 +++++++++++++++++++++++++++
 softmmu/vl.c                         |   4 +
 block/meson.build                    |   1 +
 4 files changed, 702 insertions(+)
 create mode 100644 block/export/vhost-user-blk-server.h
 create mode 100644 block/export/vhost-user-blk-server.c

diff --git a/block/export/vhost-user-blk-server.h b/block/export/vhost-user-blk-server.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/block/export/vhost-user-blk-server.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * Sharing QEMU block devices via vhost-user protocal
+ *
+ * Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
+ * Copyright (c) 2020 Red Hat, Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+
+#ifndef VHOST_USER_BLK_SERVER_H
+#define VHOST_USER_BLK_SERVER_H
+#include "util/vhost-user-server.h"
+
+typedef struct VuBlockDev VuBlockDev;
+#define TYPE_VHOST_USER_BLK_SERVER "vhost-user-blk-server"
+#define VHOST_USER_BLK_SERVER(obj) \
+   OBJECT_CHECK(VuBlockDev, obj, TYPE_VHOST_USER_BLK_SERVER)
+
+/* vhost user block device */
+struct VuBlockDev {
+    Object parent_obj;
+    char *node_name;
+    SocketAddress *addr;
+    AioContext *ctx;
+    VuServer vu_server;
+    bool running;
+    uint32_t blk_size;
+    BlockBackend *backend;
+    QIOChannelSocket *sioc;
+    QTAILQ_ENTRY(VuBlockDev) next;
+    struct virtio_blk_config blkcfg;
+    bool writable;
+};
+
+#endif /* VHOST_USER_BLK_SERVER_H */
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/block/export/vhost-user-blk-server.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Sharing QEMU block devices via vhost-user protocal
+ *
+ * Parts of the code based on nbd/server.c.
+ *
+ * Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
+ * Copyright (c) 2020 Red Hat, Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+#include "qemu/osdep.h"
+#include "block/block.h"
+#include "vhost-user-blk-server.h"
+#include "qapi/error.h"
+#include "qom/object_interfaces.h"
+#include "sysemu/block-backend.h"
+#include "util/block-helpers.h"
+
+enum {
+    VHOST_USER_BLK_MAX_QUEUES = 1,
+};
+struct virtio_blk_inhdr {
+    unsigned char status;
+};
+
+typedef struct VuBlockReq {
+    VuVirtqElement *elem;
+    int64_t sector_num;
+    size_t size;
+    struct virtio_blk_inhdr *in;
+    struct virtio_blk_outhdr out;
+    VuServer *server;
+    struct VuVirtq *vq;
+} VuBlockReq;
+
+static void vu_block_req_complete(VuBlockReq *req)
+{
+    VuDev *vu_dev = &req->server->vu_dev;
+
+    /* IO size with 1 extra status byte */
+    vu_queue_push(vu_dev, req->vq, req->elem, req->size + 1);
+    vu_queue_notify(vu_dev, req->vq);
+
+    if (req->elem) {
+        free(req->elem);
+    }
+
+    g_free(req);
+}
+
+static VuBlockDev *get_vu_block_device_by_server(VuServer *server)
+{
+    return container_of(server, VuBlockDev, vu_server);
+}
+
+static int coroutine_fn
+vu_block_discard_write_zeroes(VuBlockReq *req, struct iovec *iov,
+                              uint32_t iovcnt, uint32_t type)
+{
+    struct virtio_blk_discard_write_zeroes desc;
+    ssize_t size = iov_to_buf(iov, iovcnt, 0, &desc, sizeof(desc));
+    if (unlikely(size != sizeof(desc))) {
+        error_report("Invalid size %zd, expect %zu", size, sizeof(desc));
+        return -EINVAL;
+    }
+
+    VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server);
+    uint64_t range[2] = { le64_to_cpu(desc.sector) << 9,
+                          le32_to_cpu(desc.num_sectors) << 9 };
+    if (type == VIRTIO_BLK_T_DISCARD) {
+        if (blk_co_pdiscard(vdev_blk->backend, range[0], range[1]) == 0) {
+            return 0;
+        }
+    } else if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
+        if (blk_co_pwrite_zeroes(vdev_blk->backend,
+                                 range[0], range[1], 0) == 0) {
+            return 0;
+        }
+    }
+
+    return -EINVAL;
+}
+
+static void coroutine_fn vu_block_flush(VuBlockReq *req)
+{
+    VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server);
+    BlockBackend *backend = vdev_blk->backend;
+    blk_co_flush(backend);
+}
+
+struct req_data {
+    VuServer *server;
+    VuVirtq *vq;
+    VuVirtqElement *elem;
+};
+
+static void coroutine_fn vu_block_virtio_process_req(void *opaque)
+{
+    struct req_data *data = opaque;
+    VuServer *server = data->server;
+    VuVirtq *vq = data->vq;
+    VuVirtqElement *elem = data->elem;
+    uint32_t type;
+    VuBlockReq *req;
+
+    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
+    BlockBackend *backend = vdev_blk->backend;
+
+    struct iovec *in_iov = elem->in_sg;
+    struct iovec *out_iov = elem->out_sg;
+    unsigned in_num = elem->in_num;
+    unsigned out_num = elem->out_num;
+    /* refer to hw/block/virtio_blk.c */
+    if (elem->out_num < 1 || elem->in_num < 1) {
+        error_report("virtio-blk request missing headers");
+        free(elem);
+        return;
+    }
+
+    req = g_new0(VuBlockReq, 1);
+    req->server = server;
+    req->vq = vq;
+    req->elem = elem;
+
+    if (unlikely(iov_to_buf(out_iov, out_num, 0, &req->out,
+                            sizeof(req->out)) != sizeof(req->out))) {
+        error_report("virtio-blk request outhdr too short");
+        goto err;
+    }
+
+    iov_discard_front(&out_iov, &out_num, sizeof(req->out));
+
+    if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) {
+        error_report("virtio-blk request inhdr too short");
+        goto err;
+    }
+
+    /* We always touch the last byte, so just see how big in_iov is.  */
+    req->in = (void *)in_iov[in_num - 1].iov_base
+              + in_iov[in_num - 1].iov_len
+              - sizeof(struct virtio_blk_inhdr);
+    iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr));
+
+    type = le32_to_cpu(req->out.type);
+    switch (type & ~VIRTIO_BLK_T_BARRIER) {
+    case VIRTIO_BLK_T_IN:
+    case VIRTIO_BLK_T_OUT: {
+        ssize_t ret = 0;
+        bool is_write = type & VIRTIO_BLK_T_OUT;
+        req->sector_num = le64_to_cpu(req->out.sector);
+
+        int64_t offset = req->sector_num * vdev_blk->blk_size;
+        QEMUIOVector qiov;
+        if (is_write) {
+            qemu_iovec_init_external(&qiov, out_iov, out_num);
+            ret = blk_co_pwritev(backend, offset, qiov.size,
+                                 &qiov, 0);
+        } else {
+            qemu_iovec_init_external(&qiov, in_iov, in_num);
+            ret = blk_co_preadv(backend, offset, qiov.size,
+                                &qiov, 0);
+        }
+        if (ret >= 0) {
+            req->in->status = VIRTIO_BLK_S_OK;
+        } else {
+            req->in->status = VIRTIO_BLK_S_IOERR;
+        }
+        break;
+    }
+    case VIRTIO_BLK_T_FLUSH:
+        vu_block_flush(req);
+        req->in->status = VIRTIO_BLK_S_OK;
+        break;
+    case VIRTIO_BLK_T_GET_ID: {
+        size_t size = MIN(iov_size(&elem->in_sg[0], in_num),
+                          VIRTIO_BLK_ID_BYTES);
+        snprintf(elem->in_sg[0].iov_base, size, "%s", "vhost_user_blk");
+        req->in->status = VIRTIO_BLK_S_OK;
+        req->size = elem->in_sg[0].iov_len;
+        break;
+    }
+    case VIRTIO_BLK_T_DISCARD:
+    case VIRTIO_BLK_T_WRITE_ZEROES: {
+        int rc;
+        rc = vu_block_discard_write_zeroes(req, &elem->out_sg[1],
+                                           out_num, type);
+        if (rc == 0) {
+            req->in->status = VIRTIO_BLK_S_OK;
+        } else {
+            req->in->status = VIRTIO_BLK_S_IOERR;
+        }
+        break;
+    }
+    default:
+        req->in->status = VIRTIO_BLK_S_UNSUPP;
+        break;
+    }
+
+    vu_block_req_complete(req);
+    return;
+
+err:
+    free(elem);
+    g_free(req);
+    return;
+}
+
+static void vu_block_process_vq(VuDev *vu_dev, int idx)
+{
+    VuServer *server;
+    VuVirtq *vq;
+    struct req_data *req_data;
+
+    server = container_of(vu_dev, VuServer, vu_dev);
+    assert(server);
+
+    vq = vu_get_queue(vu_dev, idx);
+    assert(vq);
+    VuVirtqElement *elem;
+    while (1) {
+        elem = vu_queue_pop(vu_dev, vq, sizeof(VuVirtqElement) +
+                                    sizeof(VuBlockReq));
+        if (elem) {
+            req_data = g_new0(struct req_data, 1);
+            req_data->server = server;
+            req_data->vq = vq;
+            req_data->elem = elem;
+            Coroutine *co = qemu_coroutine_create(vu_block_virtio_process_req,
+                                                  req_data);
+            aio_co_enter(server->ioc->ctx, co);
+        } else {
+            break;
+        }
+    }
+}
+
+static void vu_block_queue_set_started(VuDev *vu_dev, int idx, bool started)
+{
+    VuVirtq *vq;
+
+    assert(vu_dev);
+
+    vq = vu_get_queue(vu_dev, idx);
+    vu_set_queue_handler(vu_dev, vq, started ? vu_block_process_vq : NULL);
+}
+
+static uint64_t vu_block_get_features(VuDev *dev)
+{
+    uint64_t features;
+    VuServer *server = container_of(dev, VuServer, vu_dev);
+    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
+    features = 1ull << VIRTIO_BLK_F_SIZE_MAX |
+               1ull << VIRTIO_BLK_F_SEG_MAX |
+               1ull << VIRTIO_BLK_F_TOPOLOGY |
+               1ull << VIRTIO_BLK_F_BLK_SIZE |
+               1ull << VIRTIO_BLK_F_FLUSH |
+               1ull << VIRTIO_BLK_F_DISCARD |
+               1ull << VIRTIO_BLK_F_WRITE_ZEROES |
+               1ull << VIRTIO_BLK_F_CONFIG_WCE |
+               1ull << VIRTIO_F_VERSION_1 |
+               1ull << VIRTIO_RING_F_INDIRECT_DESC |
+               1ull << VIRTIO_RING_F_EVENT_IDX |
+               1ull << VHOST_USER_F_PROTOCOL_FEATURES;
+
+    if (!vdev_blk->writable) {
+        features |= 1ull << VIRTIO_BLK_F_RO;
+    }
+
+    return features;
+}
+
+static uint64_t vu_block_get_protocol_features(VuDev *dev)
+{
+    return 1ull << VHOST_USER_PROTOCOL_F_CONFIG |
+           1ull << VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD;
+}
+
+static int
+vu_block_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
+{
+    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
+    memcpy(config, &vdev_blk->blkcfg, len);
+
+    return 0;
+}
+
+static int
+vu_block_set_config(VuDev *vu_dev, const uint8_t *data,
+                    uint32_t offset, uint32_t size, uint32_t flags)
+{
+    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
+    uint8_t wce;
+
+    /* don't support live migration */
+    if (flags != VHOST_SET_CONFIG_TYPE_MASTER) {
+        return -EINVAL;
+    }
+
+    if (offset != offsetof(struct virtio_blk_config, wce) ||
+        size != 1) {
+        return -EINVAL;
+    }
+
+    wce = *data;
+    vdev_blk->blkcfg.wce = wce;
+    blk_set_enable_write_cache(vdev_blk->backend, wce);
+    return 0;
+}
+
+/*
+ * When the client disconnects, it sends a VHOST_USER_NONE request
+ * and vu_process_message will simple call exit which cause the VM
+ * to exit abruptly.
+ * To avoid this issue,  process VHOST_USER_NONE request ahead
+ * of vu_process_message.
+ *
+ */
+static int vu_block_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
+{
+    if (vmsg->request == VHOST_USER_NONE) {
+        dev->panic(dev, "disconnect");
+        return true;
+    }
+    return false;
+}
+
+static const VuDevIface vu_block_iface = {
+    .get_features          = vu_block_get_features,
+    .queue_set_started     = vu_block_queue_set_started,
+    .get_protocol_features = vu_block_get_protocol_features,
+    .get_config            = vu_block_get_config,
+    .set_config            = vu_block_set_config,
+    .process_msg           = vu_block_process_msg,
+};
+
+static void blk_aio_attached(AioContext *ctx, void *opaque)
+{
+    VuBlockDev *vub_dev = opaque;
+    aio_context_acquire(ctx);
+    vhost_user_server_set_aio_context(&vub_dev->vu_server, ctx);
+    aio_context_release(ctx);
+}
+
+static void blk_aio_detach(void *opaque)
+{
+    VuBlockDev *vub_dev = opaque;
+    AioContext *ctx = vub_dev->vu_server.ctx;
+    aio_context_acquire(ctx);
+    vhost_user_server_set_aio_context(&vub_dev->vu_server, NULL);
+    aio_context_release(ctx);
+}
+
+static void
+vu_block_initialize_config(BlockDriverState *bs,
+                           struct virtio_blk_config *config, uint32_t blk_size)
+{
+    config->capacity = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
+    config->blk_size = blk_size;
+    config->size_max = 0;
+    config->seg_max = 128 - 2;
+    config->min_io_size = 1;
+    config->opt_io_size = 1;
+    config->num_queues = VHOST_USER_BLK_MAX_QUEUES;
+    config->max_discard_sectors = 32768;
+    config->max_discard_seg = 1;
+    config->discard_sector_alignment = config->blk_size >> 9;
+    config->max_write_zeroes_sectors = 32768;
+    config->max_write_zeroes_seg = 1;
+}
+
+static VuBlockDev *vu_block_init(VuBlockDev *vu_block_device, Error **errp)
+{
+
+    BlockBackend *blk;
+    Error *local_error = NULL;
+    const char *node_name = vu_block_device->node_name;
+    bool writable = vu_block_device->writable;
+    uint64_t perm = BLK_PERM_CONSISTENT_READ;
+    int ret;
+
+    AioContext *ctx;
+
+    BlockDriverState *bs = bdrv_lookup_bs(node_name, node_name, &local_error);
+
+    if (!bs) {
+        error_propagate(errp, local_error);
+        return NULL;
+    }
+
+    if (bdrv_is_read_only(bs)) {
+        writable = false;
+    }
+
+    if (writable) {
+        perm |= BLK_PERM_WRITE;
+    }
+
+    ctx = bdrv_get_aio_context(bs);
+    aio_context_acquire(ctx);
+    bdrv_invalidate_cache(bs, NULL);
+    aio_context_release(ctx);
+
+    /*
+     * Don't allow resize while the vhost user server is running,
+     * otherwise we don't care what happens with the node.
+     */
+    blk = blk_new(bdrv_get_aio_context(bs), perm,
+                  BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
+                  BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
+    ret = blk_insert_bs(blk, bs, errp);
+
+    if (ret < 0) {
+        goto fail;
+    }
+
+    blk_set_enable_write_cache(blk, false);
+
+    blk_set_allow_aio_context_change(blk, true);
+
+    vu_block_device->blkcfg.wce = 0;
+    vu_block_device->backend = blk;
+    if (!vu_block_device->blk_size) {
+        vu_block_device->blk_size = BDRV_SECTOR_SIZE;
+    }
+    vu_block_device->blkcfg.blk_size = vu_block_device->blk_size;
+    blk_set_guest_block_size(blk, vu_block_device->blk_size);
+    vu_block_initialize_config(bs, &vu_block_device->blkcfg,
+                                   vu_block_device->blk_size);
+    return vu_block_device;
+
+fail:
+    blk_unref(blk);
+    return NULL;
+}
+
+static void vu_block_deinit(VuBlockDev *vu_block_device)
+{
+    if (vu_block_device->backend) {
+        blk_remove_aio_context_notifier(vu_block_device->backend, blk_aio_attached,
+                                        blk_aio_detach, vu_block_device);
+    }
+
+    blk_unref(vu_block_device->backend);
+}
+
+static void vhost_user_blk_server_stop(VuBlockDev *vu_block_device)
+{
+    vhost_user_server_stop(&vu_block_device->vu_server);
+    vu_block_deinit(vu_block_device);
+}
+
+static void vhost_user_blk_server_start(VuBlockDev *vu_block_device,
+                                        Error **errp)
+{
+    AioContext *ctx;
+    SocketAddress *addr = vu_block_device->addr;
+
+    if (!vu_block_init(vu_block_device, errp)) {
+        return;
+    }
+
+    ctx = bdrv_get_aio_context(blk_bs(vu_block_device->backend));
+
+    if (!vhost_user_server_start(&vu_block_device->vu_server, addr, ctx,
+                                 VHOST_USER_BLK_MAX_QUEUES,
+                                 NULL, &vu_block_iface,
+                                 errp)) {
+        goto error;
+    }
+
+    blk_add_aio_context_notifier(vu_block_device->backend, blk_aio_attached,
+                                 blk_aio_detach, vu_block_device);
+    vu_block_device->running = true;
+    return;
+
+ error:
+    vu_block_deinit(vu_block_device);
+}
+
+static bool vu_prop_modifiable(VuBlockDev *vus, Error **errp)
+{
+    if (vus->running) {
+            error_setg(errp, "The property can't be modified "
+                       "while the server is running");
+            return false;
+    }
+    return true;
+}
+
+static void vu_set_node_name(Object *obj, const char *value, Error **errp)
+{
+    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
+
+    if (!vu_prop_modifiable(vus, errp)) {
+        return;
+    }
+
+    if (vus->node_name) {
+        g_free(vus->node_name);
+    }
+
+    vus->node_name = g_strdup(value);
+}
+
+static char *vu_get_node_name(Object *obj, Error **errp)
+{
+    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
+    return g_strdup(vus->node_name);
+}
+
+static void free_socket_addr(SocketAddress *addr)
+{
+        g_free(addr->u.q_unix.path);
+        g_free(addr);
+}
+
+static void vu_set_unix_socket(Object *obj, const char *value,
+                               Error **errp)
+{
+    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
+
+    if (!vu_prop_modifiable(vus, errp)) {
+        return;
+    }
+
+    if (vus->addr) {
+        free_socket_addr(vus->addr);
+    }
+
+    SocketAddress *addr = g_new0(SocketAddress, 1);
+    addr->type = SOCKET_ADDRESS_TYPE_UNIX;
+    addr->u.q_unix.path = g_strdup(value);
+    vus->addr = addr;
+}
+
+static char *vu_get_unix_socket(Object *obj, Error **errp)
+{
+    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
+    return g_strdup(vus->addr->u.q_unix.path);
+}
+
+static bool vu_get_block_writable(Object *obj, Error **errp)
+{
+    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
+    return vus->writable;
+}
+
+static void vu_set_block_writable(Object *obj, bool value, Error **errp)
+{
+    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
+
+    if (!vu_prop_modifiable(vus, errp)) {
+            return;
+    }
+
+    vus->writable = value;
+}
+
+static void vu_get_blk_size(Object *obj, Visitor *v, const char *name,
+                            void *opaque, Error **errp)
+{
+    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
+    uint32_t value = vus->blk_size;
+
+    visit_type_uint32(v, name, &value, errp);
+}
+
+static void vu_set_blk_size(Object *obj, Visitor *v, const char *name,
+                            void *opaque, Error **errp)
+{
+    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
+
+    Error *local_err = NULL;
+    uint32_t value;
+
+    if (!vu_prop_modifiable(vus, errp)) {
+            return;
+    }
+
+    visit_type_uint32(v, name, &value, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    check_block_size(object_get_typename(obj), name, value, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    vus->blk_size = value;
+
+out:
+    error_propagate(errp, local_err);
+}
+
+static void vhost_user_blk_server_instance_finalize(Object *obj)
+{
+    VuBlockDev *vub = VHOST_USER_BLK_SERVER(obj);
+
+    vhost_user_blk_server_stop(vub);
+
+    /*
+     * Unlike object_property_add_str, object_class_property_add_str
+     * doesn't have a release method. Thus manual memory freeing is
+     * needed.
+     */
+    free_socket_addr(vub->addr);
+    g_free(vub->node_name);
+}
+
+static void vhost_user_blk_server_complete(UserCreatable *obj, Error **errp)
+{
+    VuBlockDev *vub = VHOST_USER_BLK_SERVER(obj);
+
+    vhost_user_blk_server_start(vub, errp);
+}
+
+static void vhost_user_blk_server_class_init(ObjectClass *klass,
+                                             void *class_data)
+{
+    UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
+    ucc->complete = vhost_user_blk_server_complete;
+
+    object_class_property_add_bool(klass, "writable",
+                                   vu_get_block_writable,
+                                   vu_set_block_writable);
+
+    object_class_property_add_str(klass, "node-name",
+                                  vu_get_node_name,
+                                  vu_set_node_name);
+
+    object_class_property_add_str(klass, "unix-socket",
+                                  vu_get_unix_socket,
+                                  vu_set_unix_socket);
+
+    object_class_property_add(klass, "logical-block-size", "uint32",
+                              vu_get_blk_size, vu_set_blk_size,
+                              NULL, NULL);
+}
+
+static const TypeInfo vhost_user_blk_server_info = {
+    .name = TYPE_VHOST_USER_BLK_SERVER,
+    .parent = TYPE_OBJECT,
+    .instance_size = sizeof(VuBlockDev),
+    .instance_finalize = vhost_user_blk_server_instance_finalize,
+    .class_init = vhost_user_blk_server_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        {TYPE_USER_CREATABLE},
+        {}
+    },
+};
+
+static void vhost_user_blk_server_register_types(void)
+{
+    type_register_static(&vhost_user_blk_server_info);
+}
+
+type_init(vhost_user_blk_server_register_types)
diff --git a/softmmu/vl.c b/softmmu/vl.c
index XXXXXXX..XXXXXXX 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -XXX,XX +XXX,XX @@ static bool object_create_initial(const char *type, QemuOpts *opts)
     }
 #endif
 
+    /* Reason: vhost-user-blk-server property "node-name" */
+    if (g_str_equal(type, "vhost-user-blk-server")) {
+        return false;
+    }
     /*
      * Reason: filter-* property "netdev" etc.
      */
diff --git a/block/meson.build b/block/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/block/meson.build
+++ b/block/meson.build
@@ -XXX,XX +XXX,XX @@ block_ss.add(when: 'CONFIG_WIN32', if_true: files('file-win32.c', 'win32-aio.c')
 block_ss.add(when: 'CONFIG_POSIX', if_true: [files('file-posix.c'), coref, iokit])
 block_ss.add(when: 'CONFIG_LIBISCSI', if_true: files('iscsi-opts.c'))
 block_ss.add(when: 'CONFIG_LINUX', if_true: files('nvme.c'))
+block_ss.add(when: 'CONFIG_LINUX', if_true: files('export/vhost-user-blk-server.c', '../contrib/libvhost-user/libvhost-user.c'))
 block_ss.add(when: 'CONFIG_REPLICATION', if_true: files('replication.c'))
 block_ss.add(when: 'CONFIG_SHEEPDOG', if_true: files('sheepdog.c'))
 block_ss.add(when: ['CONFIG_LINUX_AIO', libaio], if_true: files('linux-aio.c'))
-- 
2.26.2

From: Coiby Xu <coiby.xu@gmail.com>

Suggested-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20200918080912.321299-8-coiby.xu@gmail.com
[Removed reference to vhost-user-blk-test.c, it will be sent in a
separate pull request.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ L: qemu-block@nongnu.org
 S: Supported
 F: tests/image-fuzzer/
 
+Vhost-user block device backend server
+M: Coiby Xu <Coiby.Xu@gmail.com>
+S: Maintained
+F: block/export/vhost-user-blk-server.c
+F: util/vhost-user-server.c
+F: tests/qtest/libqos/vhost-user-blk.c
+
 Replication
 M: Wen Congyang <wencongyang2@huawei.com>
 M: Xie Changlong <xiechanglong.d@gmail.com>
-- 
2.26.2

Explicitly deleting watches is not necessary since libvhost-user calls
remove_watch() during vu_deinit(). Add an assertion to check this
though.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200924151549.913737-5-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 util/vhost-user-server.c | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
index XXXXXXX..XXXXXXX 100644
--- a/util/vhost-user-server.c
+++ b/util/vhost-user-server.c
@@ -XXX,XX +XXX,XX @@ static void close_client(VuServer *server)
     /* When this is set vu_client_trip will stop new processing vhost-user message */
     server->sioc = NULL;
 
-    VuFdWatch *vu_fd_watch, *next;
-    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
-        aio_set_fd_handler(server->ioc->ctx, vu_fd_watch->fd, true, NULL,
-                           NULL, NULL, NULL);
-    }
-
-    while (!QTAILQ_EMPTY(&server->vu_fd_watches)) {
-        QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
-            if (!vu_fd_watch->processing) {
-                QTAILQ_REMOVE(&server->vu_fd_watches, vu_fd_watch, next);
-                g_free(vu_fd_watch);
-            }
-        }
-    }
-
     while (server->processing_msg) {
         if (server->ioc->read_coroutine) {
             server->ioc->read_coroutine = NULL;
@@ -XXX,XX +XXX,XX @@ static void close_client(VuServer *server)
     }
 
     vu_deinit(&server->vu_dev);
+
+    /* vu_deinit() should have called remove_watch() */
+    assert(QTAILQ_EMPTY(&server->vu_fd_watches));
+
     object_unref(OBJECT(sioc));
     object_unref(OBJECT(server->ioc));
 }
-- 
2.26.2

Only one struct is needed per request. Drop req_data and the separate
VuBlockReq instance. Instead let vu_queue_pop() allocate everything at
once.

This fixes the req_data memory leak in vu_block_virtio_process_req().

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200924151549.913737-6-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/export/vhost-user-blk-server.c | 68 +++++++++-------------------
 1 file changed, 21 insertions(+), 47 deletions(-)

diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index XXXXXXX..XXXXXXX 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -XXX,XX +XXX,XX @@ struct virtio_blk_inhdr {
 };
 
 typedef struct VuBlockReq {
-    VuVirtqElement *elem;
+    VuVirtqElement elem;
     int64_t sector_num;
     size_t size;
     struct virtio_blk_inhdr *in;
@@ -XXX,XX +XXX,XX @@ static void vu_block_req_complete(VuBlockReq *req)
     VuDev *vu_dev = &req->server->vu_dev;
 
     /* IO size with 1 extra status byte */
-    vu_queue_push(vu_dev, req->vq, req->elem, req->size + 1);
+    vu_queue_push(vu_dev, req->vq, &req->elem, req->size + 1);
     vu_queue_notify(vu_dev, req->vq);
 
-    if (req->elem) {
-        free(req->elem);
-    }
-
-    g_free(req);
+    free(req);
 }
 
 static VuBlockDev *get_vu_block_device_by_server(VuServer *server)
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_flush(VuBlockReq *req)
     blk_co_flush(backend);
 }
 
-struct req_data {
-    VuServer *server;
-    VuVirtq *vq;
-    VuVirtqElement *elem;
-};
-
 static void coroutine_fn vu_block_virtio_process_req(void *opaque)
 {
-    struct req_data *data = opaque;
-    VuServer *server = data->server;
-    VuVirtq *vq = data->vq;
-    VuVirtqElement *elem = data->elem;
+    VuBlockReq *req = opaque;
+    VuServer *server = req->server;
+    VuVirtqElement *elem = &req->elem;
     uint32_t type;
-    VuBlockReq *req;
 
     VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
     BlockBackend *backend = vdev_blk->backend;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
     struct iovec *out_iov = elem->out_sg;
     unsigned in_num = elem->in_num;
     unsigned out_num = elem->out_num;
+
     /* refer to hw/block/virtio_blk.c */
     if (elem->out_num < 1 || elem->in_num < 1) {
         error_report("virtio-blk request missing headers");
-        free(elem);
-        return;
+        goto err;
     }
 
-    req = g_new0(VuBlockReq, 1);
-    req->server = server;
-    req->vq = vq;
-    req->elem = elem;
-
     if (unlikely(iov_to_buf(out_iov, out_num, 0, &req->out,
                             sizeof(req->out)) != sizeof(req->out))) {
         error_report("virtio-blk request outhdr too short");
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
 
 err:
     free(elem);
-    g_free(req);
-    return;
 }
 
 static void vu_block_process_vq(VuDev *vu_dev, int idx)
 {
-    VuServer *server;
-    VuVirtq *vq;
-    struct req_data *req_data;
+    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+    VuVirtq *vq = vu_get_queue(vu_dev, idx);
 
-    server = container_of(vu_dev, VuServer, vu_dev);
-    assert(server);
-
-    vq = vu_get_queue(vu_dev, idx);
-    assert(vq);
-    VuVirtqElement *elem;
     while (1) {
-        elem = vu_queue_pop(vu_dev, vq, sizeof(VuVirtqElement) +
-                                    sizeof(VuBlockReq));
-        if (elem) {
-            req_data = g_new0(struct req_data, 1);
-            req_data->server = server;
-            req_data->vq = vq;
-            req_data->elem = elem;
-            Coroutine *co = qemu_coroutine_create(vu_block_virtio_process_req,
-                                                  req_data);
-            aio_co_enter(server->ioc->ctx, co);
-        } else {
+        VuBlockReq *req;
+
+        req = vu_queue_pop(vu_dev, vq, sizeof(VuBlockReq));
+        if (!req) {
             break;
         }
+
+        req->server = server;
+        req->vq = vq;
+
+        Coroutine *co =
+            qemu_coroutine_create(vu_block_virtio_process_req, req);
+        qemu_coroutine_enter(co);
     }
 }
 
-- 
2.26.2

The device panic notifier callback is not used. Drop it.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200924151549.913737-7-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 util/vhost-user-server.h             | 3 ---
 block/export/vhost-user-blk-server.c | 3 +--
 util/vhost-user-server.c             | 6 ------
 3 files changed, 1 insertion(+), 11 deletions(-)

diff --git a/util/vhost-user-server.h b/util/vhost-user-server.h
index XXXXXXX..XXXXXXX 100644
--- a/util/vhost-user-server.h
+++ b/util/vhost-user-server.h
@@ -XXX,XX +XXX,XX @@ typedef struct VuFdWatch {
 } VuFdWatch;
 
 typedef struct VuServer VuServer;
-typedef void DevicePanicNotifierFn(VuServer *server);
 
 struct VuServer {
     QIONetListener *listener;
     AioContext *ctx;
-    DevicePanicNotifierFn *device_panic_notifier;
     int max_queues;
     const VuDevIface *vu_iface;
     VuDev vu_dev;
@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
                              SocketAddress *unix_socket,
                              AioContext *ctx,
                              uint16_t max_queues,
-                             DevicePanicNotifierFn *device_panic_notifier,
                              const VuDevIface *vu_iface,
                              Error **errp);
 
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index XXXXXXX..XXXXXXX 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -XXX,XX +XXX,XX @@ static void vhost_user_blk_server_start(VuBlockDev *vu_block_device,
     ctx = bdrv_get_aio_context(blk_bs(vu_block_device->backend));
 
     if (!vhost_user_server_start(&vu_block_device->vu_server, addr, ctx,
-                                 VHOST_USER_BLK_MAX_QUEUES,
-                                 NULL, &vu_block_iface,
+                                 VHOST_USER_BLK_MAX_QUEUES, &vu_block_iface,
                                  errp)) {
         goto error;
     }
diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
index XXXXXXX..XXXXXXX 100644
--- a/util/vhost-user-server.c
+++ b/util/vhost-user-server.c
@@ -XXX,XX +XXX,XX @@ static void panic_cb(VuDev *vu_dev, const char *buf)
         close_client(server);
     }
 
-    if (server->device_panic_notifier) {
-        server->device_panic_notifier(server);
-    }
-
     /*
      * Set the callback function for network listener so another
      * vhost-user client can connect to this server
@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
                              SocketAddress *socket_addr,
                              AioContext *ctx,
                              uint16_t max_queues,
-                             DevicePanicNotifierFn *device_panic_notifier,
                              const VuDevIface *vu_iface,
                              Error **errp)
 {
@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
         .vu_iface              = vu_iface,
         .max_queues            = max_queues,
         .ctx                   = ctx,
-        .device_panic_notifier = device_panic_notifier,
     };
 
     qio_net_listener_set_name(server->listener, "vhost-user-backend-listener");
-- 
2.26.2

fds[] is leaked when qio_channel_readv_full() fails.

Use vmsg->fds[] instead of keeping a local fds[] array. Then we can
reuse goto fail to clean up fds. vmsg->fd_num must be zeroed before the
loop to make this safe.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200924151549.913737-8-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 util/vhost-user-server.c | 50 ++++++++++++++++++----------------------
 1 file changed, 23 insertions(+), 27 deletions(-)

diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
index XXXXXXX..XXXXXXX 100644
--- a/util/vhost-user-server.c
+++ b/util/vhost-user-server.c
@@ -XXX,XX +XXX,XX @@ vu_message_read(VuDev *vu_dev, int conn_fd, VhostUserMsg *vmsg)
     };
     int rc, read_bytes = 0;
     Error *local_err = NULL;
-    /*
-     * Store fds/nfds returned from qio_channel_readv_full into
-     * temporary variables.
-     *
-     * VhostUserMsg is a packed structure, gcc will complain about passing
-     * pointer to a packed structure member if we pass &VhostUserMsg.fd_num
-     * and &VhostUserMsg.fds directly when calling qio_channel_readv_full,
-     * thus two temporary variables nfds and fds are used here.
-     */
-    size_t nfds = 0, nfds_t = 0;
     const size_t max_fds = G_N_ELEMENTS(vmsg->fds);
-    int *fds_t = NULL;
     VuServer *server = container_of(vu_dev, VuServer, vu_dev);
     QIOChannel *ioc = server->ioc;
 
+    vmsg->fd_num = 0;
     if (!ioc) {
         error_report_err(local_err);
         goto fail;
@@ -XXX,XX +XXX,XX @@ vu_message_read(VuDev *vu_dev, int conn_fd, VhostUserMsg *vmsg)
 
     assert(qemu_in_coroutine());
     do {
+        size_t nfds = 0;
+        int *fds = NULL;
+
         /*
          * qio_channel_readv_full may have short reads, keeping calling it
          * until getting VHOST_USER_HDR_SIZE or 0 bytes in total
          */
-        rc = qio_channel_readv_full(ioc, &iov, 1, &fds_t, &nfds_t, &local_err);
+        rc = qio_channel_readv_full(ioc, &iov, 1, &fds, &nfds, &local_err);
         if (rc < 0) {
             if (rc == QIO_CHANNEL_ERR_BLOCK) {
+                assert(local_err == NULL);
                 qio_channel_yield(ioc, G_IO_IN);
                 continue;
             } else {
                 error_report_err(local_err);
-                return false;
+                goto fail;
             }
         }
-        read_bytes += rc;
-        if (nfds_t > 0) {
-            if (nfds + nfds_t > max_fds) {
+
+        if (nfds > 0) {
+            if (vmsg->fd_num + nfds > max_fds) {
                 error_report("A maximum of %zu fds are allowed, "
                              "however got %zu fds now",
-                             max_fds, nfds + nfds_t);
+                             max_fds, vmsg->fd_num + nfds);
+                g_free(fds);
                 goto fail;
             }
-            memcpy(vmsg->fds + nfds, fds_t,
-                   nfds_t *sizeof(vmsg->fds[0]));
-            nfds += nfds_t;
-            g_free(fds_t);
+            memcpy(vmsg->fds + vmsg->fd_num, fds, nfds * sizeof(vmsg->fds[0]));
+            vmsg->fd_num += nfds;
+            g_free(fds);
         }
-        if (read_bytes == VHOST_USER_HDR_SIZE || rc == 0) {
-            break;
+
+        if (rc == 0) { /* socket closed */
+            goto fail;
         }
-        iov.iov_base = (char *)vmsg + read_bytes;
-        iov.iov_len = VHOST_USER_HDR_SIZE - read_bytes;
-    } while (true);
 
-    vmsg->fd_num = nfds;
+        iov.iov_base += rc;
+        iov.iov_len -= rc;
+        read_bytes += rc;
+    } while (read_bytes != VHOST_USER_HDR_SIZE);
+
     /* qio_channel_readv_full will make socket fds blocking, unblock them */
     vmsg_unblock_fds(vmsg);
     if (vmsg->size > sizeof(vmsg->payload)) {
-- 
2.26.2

The vu_client_trip() coroutine is leaked during AioContext switching. It
is also unsafe to destroy the vu_dev in panic_cb() since its callers
still access it in some cases.

Rework the lifecycle to solve these safety issues.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200924151549.913737-10-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 util/vhost-user-server.h             |  29 ++--
 block/export/vhost-user-blk-server.c |   9 +-
 util/vhost-user-server.c             | 245 +++++++++++++++------------
 3 files changed, 155 insertions(+), 128 deletions(-)

diff --git a/util/vhost-user-server.h b/util/vhost-user-server.h
index XXXXXXX..XXXXXXX 100644
--- a/util/vhost-user-server.h
+++ b/util/vhost-user-server.h
@@ -XXX,XX +XXX,XX @@
 #include "qapi/error.h"
 #include "standard-headers/linux/virtio_blk.h"
 
+/* A kick fd that we monitor on behalf of libvhost-user */
 typedef struct VuFdWatch {
     VuDev *vu_dev;
     int fd; /*kick fd*/
     void *pvt;
     vu_watch_cb cb;
-    bool processing;
     QTAILQ_ENTRY(VuFdWatch) next;
 } VuFdWatch;
 
-typedef struct VuServer VuServer;
-
-struct VuServer {
+/**
+ * VuServer:
+ * A vhost-user server instance with user-defined VuDevIface callbacks.
+ * Vhost-user device backends can be implemented using VuServer. VuDevIface
+ * callbacks and virtqueue kicks run in the given AioContext.
+ */
+typedef struct {
     QIONetListener *listener;
+    QEMUBH *restart_listener_bh;
     AioContext *ctx;
     int max_queues;
     const VuDevIface *vu_iface;
+
+    /* Protected by ctx lock */
     VuDev vu_dev;
     QIOChannel *ioc; /* The I/O channel with the client */
     QIOChannelSocket *sioc; /* The underlying data channel with the client */
-    /* IOChannel for fd provided via VHOST_USER_SET_SLAVE_REQ_FD */
-    QIOChannel *ioc_slave;
-    QIOChannelSocket *sioc_slave;
-    Coroutine *co_trip; /* coroutine for processing VhostUserMsg */
     QTAILQ_HEAD(, VuFdWatch) vu_fd_watches;
-    /* restart coroutine co_trip if AIOContext is changed */
-    bool aio_context_changed;
-    bool processing_msg;
-};
+
+    Coroutine *co_trip; /* coroutine for processing VhostUserMsg */
+} VuServer;
 
 bool vhost_user_server_start(VuServer *server,
                              SocketAddress *unix_socket,
@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
 
 void vhost_user_server_stop(VuServer *server);
 
-void vhost_user_server_set_aio_context(VuServer *server, AioContext *ctx);
+void vhost_user_server_attach_aio_context(VuServer *server, AioContext *ctx);
+void vhost_user_server_detach_aio_context(VuServer *server);
 
 #endif /* VHOST_USER_SERVER_H */
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index XXXXXXX..XXXXXXX 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -XXX,XX +XXX,XX @@ static const VuDevIface vu_block_iface = {
 static void blk_aio_attached(AioContext *ctx, void *opaque)
 {
     VuBlockDev *vub_dev = opaque;
-    aio_context_acquire(ctx);
-    vhost_user_server_set_aio_context(&vub_dev->vu_server, ctx);
-    aio_context_release(ctx);
+    vhost_user_server_attach_aio_context(&vub_dev->vu_server, ctx);
 }
 
 static void blk_aio_detach(void *opaque)
 {
     VuBlockDev *vub_dev = opaque;
-    AioContext *ctx = vub_dev->vu_server.ctx;
-    aio_context_acquire(ctx);
-    vhost_user_server_set_aio_context(&vub_dev->vu_server, NULL);
-    aio_context_release(ctx);
+    vhost_user_server_detach_aio_context(&vub_dev->vu_server);
 }
 
 static void
diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
index XXXXXXX..XXXXXXX 100644
--- a/util/vhost-user-server.c
+++ b/util/vhost-user-server.c
@@ -XXX,XX +XXX,XX @@
  */
 #include "qemu/osdep.h"
 #include "qemu/main-loop.h"
+#include "block/aio-wait.h"
 #include "vhost-user-server.h"
 
+/*
+ * Theory of operation:
+ *
+ * VuServer is started and stopped by vhost_user_server_start() and
+ * vhost_user_server_stop() from the main loop thread. Starting the server
+ * opens a vhost-user UNIX domain socket and listens for incoming connections.
+ * Only one connection is allowed at a time.
+ *
+ * The connection is handled by the vu_client_trip() coroutine in the
+ * VuServer->ctx AioContext. The coroutine consists of a vu_dispatch() loop
+ * where libvhost-user calls vu_message_read() to receive the next vhost-user
+ * protocol messages over the UNIX domain socket.
+ *
+ * When virtqueues are set up libvhost-user calls set_watch() to monitor kick
+ * fds. These fds are also handled in the VuServer->ctx AioContext.
+ *
+ * Both vu_client_trip() and kick fd monitoring can be stopped by shutting down
+ * the socket connection. Shutting down the socket connection causes
+ * vu_message_read() to fail since no more data can be received from the socket.
+ * After vu_dispatch() fails, vu_client_trip() calls vu_deinit() to stop
+ * libvhost-user before terminating the coroutine. vu_deinit() calls
+ * remove_watch() to stop monitoring kick fds and this stops virtqueue
+ * processing.
+ *
+ * When vu_client_trip() has finished cleaning up it schedules a BH in the main
+ * loop thread to accept the next client connection.
+ *
+ * When libvhost-user detects an error it calls panic_cb() and sets the
+ * dev->broken flag. Both vu_client_trip() and kick fd processing stop when
+ * the dev->broken flag is set.
+ *
+ * It is possible to switch AioContexts using
+ * vhost_user_server_detach_aio_context() and
+ * vhost_user_server_attach_aio_context(). They stop monitoring fds in the old
+ * AioContext and resume monitoring in the new AioContext. The vu_client_trip()
+ * coroutine remains in a yielded state during the switch. This is made
+ * possible by QIOChannel's support for spurious coroutine re-entry in
+ * qio_channel_yield(). The coroutine will restart I/O when re-entered from the
+ * new AioContext.
+ */
+
 static void vmsg_close_fds(VhostUserMsg *vmsg)
 {
     int i;
@@ -XXX,XX +XXX,XX @@ static void vmsg_unblock_fds(VhostUserMsg *vmsg)
     }
 }
 
-static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
-                      gpointer opaque);
-
-static void close_client(VuServer *server)
-{
-    /*
-     * Before closing the client
-     *
-     * 1. Let vu_client_trip stop processing new vhost-user msg
-     *
-     * 2. remove kick_handler
-     *
-     * 3. wait for the kick handler to be finished
-     *
-     * 4. wait for the current vhost-user msg to be finished processing
-     */
-
-    QIOChannelSocket *sioc = server->sioc;
-    /* When this is set vu_client_trip will stop new processing vhost-user message */
-    server->sioc = NULL;
-
-    while (server->processing_msg) {
-        if (server->ioc->read_coroutine) {
-            server->ioc->read_coroutine = NULL;
-            qio_channel_set_aio_fd_handler(server->ioc, server->ioc->ctx, NULL,
-                                           NULL, server->ioc);
-            server->processing_msg = false;
-        }
-    }
-
-    vu_deinit(&server->vu_dev);
-
-    /* vu_deinit() should have called remove_watch() */
-    assert(QTAILQ_EMPTY(&server->vu_fd_watches));
-
-    object_unref(OBJECT(sioc));
-    object_unref(OBJECT(server->ioc));
-}
-
 static void panic_cb(VuDev *vu_dev, const char *buf)
 {
-    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
-
-    /* avoid while loop in close_client */
-    server->processing_msg = false;
-
-    if (buf) {
-        error_report("vu_panic: %s", buf);
-    }
-
-    if (server->sioc) {
-        close_client(server);
-    }
-
-    /*
-     * Set the callback function for network listener so another
-     * vhost-user client can connect to this server
-     */
-    qio_net_listener_set_client_func(server->listener,
-                                     vu_accept,
-                                     server,
-                                     NULL);
+    error_report("vu_panic: %s", buf);
 }
 
 static bool coroutine_fn
@@ -XXX,XX +XXX,XX @@ fail:
     return false;
 }
 
-
-static void vu_client_start(VuServer *server);
 static coroutine_fn void vu_client_trip(void *opaque)
 {
     VuServer *server = opaque;
+    VuDev *vu_dev = &server->vu_dev;
 
-    while (!server->aio_context_changed && server->sioc) {
-        server->processing_msg = true;
-        vu_dispatch(&server->vu_dev);
-        server->processing_msg = false;
+    while (!vu_dev->broken && vu_dispatch(vu_dev)) {
+        /* Keep running */
     }
 
-    if (server->aio_context_changed && server->sioc) {
-        server->aio_context_changed = false;
-        vu_client_start(server);
-    }
-}
+    vu_deinit(vu_dev);
+
+    /* vu_deinit() should have called remove_watch() */
+    assert(QTAILQ_EMPTY(&server->vu_fd_watches));
+
+    object_unref(OBJECT(server->sioc));
+    server->sioc = NULL;
 
-static void vu_client_start(VuServer *server)
-{
-    server->co_trip = qemu_coroutine_create(vu_client_trip, server);
-    aio_co_enter(server->ctx, server->co_trip);
+    object_unref(OBJECT(server->ioc));
+    server->ioc = NULL;
+
+    server->co_trip = NULL;
+    if (server->restart_listener_bh) {
+        qemu_bh_schedule(server->restart_listener_bh);
+    }
+    aio_wait_kick();
 }
 
 /*
@@ -XXX,XX +XXX,XX @@ static void vu_client_start(VuServer *server)
 static void kick_handler(void *opaque)
 {
     VuFdWatch *vu_fd_watch = opaque;
-    vu_fd_watch->processing = true;
-    vu_fd_watch->cb(vu_fd_watch->vu_dev, 0, vu_fd_watch->pvt);
-    vu_fd_watch->processing = false;
+    VuDev *vu_dev = vu_fd_watch->vu_dev;
+
+    vu_fd_watch->cb(vu_dev, 0, vu_fd_watch->pvt);
+
+    /* Stop vu_client_trip() if an error occurred in vu_fd_watch->cb() */
+    if (vu_dev->broken) {
+        VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+
+        qio_channel_shutdown(server->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
+    }
 }
 
-
 static VuFdWatch *find_vu_fd_watch(VuServer *server, int fd)
 {
 
@@ -XXX,XX +XXX,XX @@ static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
     qio_channel_set_name(QIO_CHANNEL(sioc), "vhost-user client");
     server->ioc = QIO_CHANNEL(sioc);
     object_ref(OBJECT(server->ioc));
-    qio_channel_attach_aio_context(server->ioc, server->ctx);
+
+    /* TODO vu_message_write() spins if non-blocking! */
     qio_channel_set_blocking(server->ioc, false, NULL);
-    vu_client_start(server);
+
+    server->co_trip = qemu_coroutine_create(vu_client_trip, server);
+
+    aio_context_acquire(server->ctx);
+    vhost_user_server_attach_aio_context(server, server->ctx);
+    aio_context_release(server->ctx);
 }
 
-
 void vhost_user_server_stop(VuServer *server)
 {
+    aio_context_acquire(server->ctx);
+
+    qemu_bh_delete(server->restart_listener_bh);
+    server->restart_listener_bh = NULL;
+
     if (server->sioc) {
-        close_client(server);
+        VuFdWatch *vu_fd_watch;
+
+        QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
+            aio_set_fd_handler(server->ctx, vu_fd_watch->fd, true,
+                               NULL, NULL, NULL, vu_fd_watch);
+        }
+
+        qio_channel_shutdown(server->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
+
+        AIO_WAIT_WHILE(server->ctx, server->co_trip);
     }
 
+    aio_context_release(server->ctx);
+
     if (server->listener) {
         qio_net_listener_disconnect(server->listener);
         object_unref(OBJECT(server->listener));
     }
+}
+
+/*
+ * Allow the next client to connect to the server. Called from a BH in the main
+ * loop.
+ */
+static void restart_listener_bh(void *opaque)
+{
+    VuServer *server = opaque;
 
+    qio_net_listener_set_client_func(server->listener, vu_accept, server,
+                                     NULL);
 }
 
-void vhost_user_server_set_aio_context(VuServer *server, AioContext *ctx)
+/* Called with ctx acquired */
+void vhost_user_server_attach_aio_context(VuServer *server, AioContext *ctx)
 {
-    VuFdWatch *vu_fd_watch, *next;
-    void *opaque = NULL;
-    IOHandler *io_read = NULL;
-    bool attach;
+    VuFdWatch *vu_fd_watch;
 
-    server->ctx = ctx ? ctx : qemu_get_aio_context();
+    server->ctx = ctx;
 
     if (!server->sioc) {
-        /* not yet serving any client*/
         return;
     }
 
-    if (ctx) {
-        qio_channel_attach_aio_context(server->ioc, ctx);
-        server->aio_context_changed = true;
-        io_read = kick_handler;
-        attach = true;
-    } else {
+    qio_channel_attach_aio_context(server->ioc, ctx);
+
+    QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
+        aio_set_fd_handler(ctx, vu_fd_watch->fd, true, kick_handler, NULL,
+                           NULL, vu_fd_watch);
+    }
+
+    aio_co_schedule(ctx, server->co_trip);
+}
+
+/* Called with server->ctx acquired */
+void vhost_user_server_detach_aio_context(VuServer *server)
+{
+    if (server->sioc) {
+        VuFdWatch *vu_fd_watch;
+
+        QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
+            aio_set_fd_handler(server->ctx, vu_fd_watch->fd, true,
+                               NULL, NULL, NULL, vu_fd_watch);
+        }
+
         qio_channel_detach_aio_context(server->ioc);
-        /* server->ioc->ctx keeps the old AioConext */
-        ctx = server->ioc->ctx;
-        attach = false;
     }
 
-    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
-        if (vu_fd_watch->cb) {
-            opaque = attach ? vu_fd_watch : NULL;
-            aio_set_fd_handler(ctx, vu_fd_watch->fd, true,
-                               io_read, NULL, NULL,
-                               opaque);
-        }
-    }
+    server->ctx = NULL;
 }
 
-
 bool vhost_user_server_start(VuServer *server,
                              SocketAddress *socket_addr,
                              AioContext *ctx,
@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
                              const VuDevIface *vu_iface,
                              Error **errp)
 {
+    QEMUBH *bh;
     QIONetListener *listener = qio_net_listener_new();
     if (qio_net_listener_open_sync(listener, socket_addr, 1,
                                    errp) < 0) {
@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
         return false;
     }
 
+    bh = qemu_bh_new(restart_listener_bh, server);
+
     /* zero out unspecified fields */
     *server = (VuServer) {
         .listener              = listener,
+        .restart_listener_bh   = bh,
         .vu_iface              = vu_iface,
         .max_queues            = max_queues,
         .ctx                   = ctx,
-- 
2.26.2

Propagate the flush return value since errors are possible.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200924151549.913737-11-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/export/vhost-user-blk-server.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

Use the new QAPI block exports API instead of defining our own QOM
objects.

This is a large change because the lifecycle of VuBlockDev needs to
follow BlockExportDriver. QOM properties are replaced by QAPI options
objects.

VuBlockDev is renamed VuBlkExport and contains a BlockExport field.
Several fields can be dropped since BlockExport already has equivalents.

The file names and meson build integration will be adjusted in a future
patch. libvhost-user should probably be built as a static library that
is linked into QEMU instead of as a .c file that results in duplicate
compilation.

The new command-line syntax is:

$ qemu-storage-daemon \
      --blockdev file,node-name=drive0,filename=test.img \
      --export vhost-user-blk,node-name=drive0,id=export0,unix-socket=/tmp/vhost-user-blk.sock

Note that unix-socket is optional because we may wish to accept chardevs
too in the future.

Markus noted that supported address families are not explicit in the
QAPI schema. It is unlikely that support for more address families will
be added since file descriptor passing is required and few address
families support it. If a new address family needs to be added, then the
QAPI 'features' syntax can be used to advertize them.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20200924151549.913737-12-stefanha@redhat.com
[Skip test on big-endian host architectures because this device doesn't
support them yet (as already mentioned in a code comment).
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 qapi/block-export.json               |  21 +-
 block/export/vhost-user-blk-server.h |  23 +-
 block/export/export.c                |   6 +
 block/export/vhost-user-blk-server.c | 452 +++++++--------------------
 util/vhost-user-server.c             |  10 +-
 block/export/meson.build             |   1 +
 block/meson.build                    |   1 -
 7 files changed, 156 insertions(+), 358 deletions(-)

diff --git a/qapi/block-export.json b/qapi/block-export.json
index XXXXXXX..XXXXXXX 100644
--- a/qapi/block-export.json
+++ b/qapi/block-export.json
@@ -XXX,XX +XXX,XX @@
   'data': { '*name': 'str', '*description': 'str',
             '*bitmap': 'str' } }
 
+##
+# @BlockExportOptionsVhostUserBlk:
+#
+# A vhost-user-blk block export.
+#
+# @addr: The vhost-user socket on which to listen. Both 'unix' and 'fd'
+#        SocketAddress types are supported. Passed fds must be UNIX domain
+#        sockets.
+# @logical-block-size: Logical block size in bytes. Defaults to 512 bytes.
+#
+# Since: 5.2
+##
+{ 'struct': 'BlockExportOptionsVhostUserBlk',
+  'data': { 'addr': 'SocketAddress', '*logical-block-size': 'size' } }
+
 ##
 # @NbdServerAddOptions:
 #
@@ -XXX,XX +XXX,XX @@
 # An enumeration of block export types
 #
 # @nbd: NBD export
+# @vhost-user-blk: vhost-user-blk export (since 5.2)
 #
 # Since: 4.2
 ##
 { 'enum': 'BlockExportType',
-  'data': [ 'nbd' ] }
+  'data': [ 'nbd', 'vhost-user-blk' ] }
 
 ##
 # @BlockExportOptions:
@@ -XXX,XX +XXX,XX @@
             '*writethrough': 'bool' },
   'discriminator': 'type',
   'data': {
-      'nbd': 'BlockExportOptionsNbd'
+      'nbd': 'BlockExportOptionsNbd',
+      'vhost-user-blk': 'BlockExportOptionsVhostUserBlk'
    } }
 
 ##
diff --git a/block/export/vhost-user-blk-server.h b/block/export/vhost-user-blk-server.h
index XXXXXXX..XXXXXXX 100644
--- a/block/export/vhost-user-blk-server.h
+++ b/block/export/vhost-user-blk-server.h
@@ -XXX,XX +XXX,XX @@
 
 #ifndef VHOST_USER_BLK_SERVER_H
 #define VHOST_USER_BLK_SERVER_H
-#include "util/vhost-user-server.h"
 
-typedef struct VuBlockDev VuBlockDev;
-#define TYPE_VHOST_USER_BLK_SERVER "vhost-user-blk-server"
-#define VHOST_USER_BLK_SERVER(obj) \
-   OBJECT_CHECK(VuBlockDev, obj, TYPE_VHOST_USER_BLK_SERVER)
+#include "block/export.h"
 
-/* vhost user block device */
-struct VuBlockDev {
-    Object parent_obj;
-    char *node_name;
-    SocketAddress *addr;
-    AioContext *ctx;
-    VuServer vu_server;
-    bool running;
-    uint32_t blk_size;
-    BlockBackend *backend;
-    QIOChannelSocket *sioc;
-    QTAILQ_ENTRY(VuBlockDev) next;
-    struct virtio_blk_config blkcfg;
-    bool writable;
-};
+/* For block/export/export.c */
+extern const BlockExportDriver blk_exp_vhost_user_blk;
 
 #endif /* VHOST_USER_BLK_SERVER_H */
diff --git a/block/export/export.c b/block/export/export.c
index XXXXXXX..XXXXXXX 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -XXX,XX +XXX,XX @@
 #include "sysemu/block-backend.h"
 #include "block/export.h"
 #include "block/nbd.h"
+#if CONFIG_LINUX
+#include "block/export/vhost-user-blk-server.h"
+#endif
 #include "qapi/error.h"
 #include "qapi/qapi-commands-block-export.h"
 #include "qapi/qapi-events-block-export.h"
@@ -XXX,XX +XXX,XX @@
 
 static const BlockExportDriver *blk_exp_drivers[] = {
     &blk_exp_nbd,
+#if CONFIG_LINUX
+    &blk_exp_vhost_user_blk,
+#endif
 };
 
 /* Only accessed from the main thread */
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index XXXXXXX..XXXXXXX 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -XXX,XX +XXX,XX @@
  */
 #include "qemu/osdep.h"
 #include "block/block.h"
+#include "contrib/libvhost-user/libvhost-user.h"
+#include "standard-headers/linux/virtio_blk.h"
+#include "util/vhost-user-server.h"
 #include "vhost-user-blk-server.h"
 #include "qapi/error.h"
 #include "qom/object_interfaces.h"
@@ -XXX,XX +XXX,XX @@ struct virtio_blk_inhdr {
     unsigned char status;
 };
 
-typedef struct VuBlockReq {
+typedef struct VuBlkReq {
     VuVirtqElement elem;
     int64_t sector_num;
     size_t size;
@@ -XXX,XX +XXX,XX @@ typedef struct VuBlockReq {
     struct virtio_blk_outhdr out;
     VuServer *server;
     struct VuVirtq *vq;
-} VuBlockReq;
+} VuBlkReq;
 
-static void vu_block_req_complete(VuBlockReq *req)
+/* vhost user block device */
+typedef struct {
+    BlockExport export;
+    VuServer vu_server;
+    uint32_t blk_size;
+    QIOChannelSocket *sioc;
+    struct virtio_blk_config blkcfg;
+    bool writable;
+} VuBlkExport;
+
+static void vu_blk_req_complete(VuBlkReq *req)
 {
     VuDev *vu_dev = &req->server->vu_dev;
 
@@ -XXX,XX +XXX,XX @@ static void vu_block_req_complete(VuBlockReq *req)
     free(req);
 }
 
-static VuBlockDev *get_vu_block_device_by_server(VuServer *server)
-{
-    return container_of(server, VuBlockDev, vu_server);
-}
-
 static int coroutine_fn
-vu_block_discard_write_zeroes(VuBlockReq *req, struct iovec *iov,
-                              uint32_t iovcnt, uint32_t type)
+vu_blk_discard_write_zeroes(BlockBackend *blk, struct iovec *iov,
+                            uint32_t iovcnt, uint32_t type)
 {
     struct virtio_blk_discard_write_zeroes desc;
     ssize_t size = iov_to_buf(iov, iovcnt, 0, &desc, sizeof(desc));
@@ -XXX,XX +XXX,XX @@ vu_block_discard_write_zeroes(VuBlockReq *req, struct iovec *iov,
         return -EINVAL;
     }
 
-    VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server);
     uint64_t range[2] = { le64_to_cpu(desc.sector) << 9,
                           le32_to_cpu(desc.num_sectors) << 9 };
     if (type == VIRTIO_BLK_T_DISCARD) {
-        if (blk_co_pdiscard(vdev_blk->backend, range[0], range[1]) == 0) {
+        if (blk_co_pdiscard(blk, range[0], range[1]) == 0) {
             return 0;
         }
     } else if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
-        if (blk_co_pwrite_zeroes(vdev_blk->backend,
-                                 range[0], range[1], 0) == 0) {
+        if (blk_co_pwrite_zeroes(blk, range[0], range[1], 0) == 0) {
             return 0;
         }
     }
@@ -XXX,XX +XXX,XX @@ vu_block_discard_write_zeroes(VuBlockReq *req, struct iovec *iov,
     return -EINVAL;
 }
 
-static int coroutine_fn vu_block_flush(VuBlockReq *req)
+static void coroutine_fn vu_blk_virtio_process_req(void *opaque)
 {
-    VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server);
-    BlockBackend *backend = vdev_blk->backend;
-    return blk_co_flush(backend);
-}
-
-static void coroutine_fn vu_block_virtio_process_req(void *opaque)
-{
-    VuBlockReq *req = opaque;
+    VuBlkReq *req = opaque;
     VuServer *server = req->server;
     VuVirtqElement *elem = &req->elem;
     uint32_t type;
 
-    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
-    BlockBackend *backend = vdev_blk->backend;
+    VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
+    BlockBackend *blk = vexp->export.blk;
 
     struct iovec *in_iov = elem->in_sg;
     struct iovec *out_iov = elem->out_sg;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
         bool is_write = type & VIRTIO_BLK_T_OUT;
         req->sector_num = le64_to_cpu(req->out.sector);
 
-        int64_t offset = req->sector_num * vdev_blk->blk_size;
+        if (is_write && !vexp->writable) {
+            req->in->status = VIRTIO_BLK_S_IOERR;
+            break;
+        }
+
+        int64_t offset = req->sector_num * vexp->blk_size;
         QEMUIOVector qiov;
         if (is_write) {
             qemu_iovec_init_external(&qiov, out_iov, out_num);
-            ret = blk_co_pwritev(backend, offset, qiov.size,
-                                 &qiov, 0);
+            ret = blk_co_pwritev(blk, offset, qiov.size, &qiov, 0);
         } else {
             qemu_iovec_init_external(&qiov, in_iov, in_num);
-            ret = blk_co_preadv(backend, offset, qiov.size,
-                                &qiov, 0);
+            ret = blk_co_preadv(blk, offset, qiov.size, &qiov, 0);
         }
         if (ret >= 0) {
             req->in->status = VIRTIO_BLK_S_OK;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
         break;
     }
     case VIRTIO_BLK_T_FLUSH:
-        if (vu_block_flush(req) == 0) {
+        if (blk_co_flush(blk) == 0) {
             req->in->status = VIRTIO_BLK_S_OK;
         } else {
             req->in->status = VIRTIO_BLK_S_IOERR;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
     case VIRTIO_BLK_T_DISCARD:
     case VIRTIO_BLK_T_WRITE_ZEROES: {
         int rc;
-        rc = vu_block_discard_write_zeroes(req, &elem->out_sg[1],
-                                           out_num, type);
+
+        if (!vexp->writable) {
+            req->in->status = VIRTIO_BLK_S_IOERR;
+            break;
+        }
+
+        rc = vu_blk_discard_write_zeroes(blk, &elem->out_sg[1], out_num, type);
         if (rc == 0) {
             req->in->status = VIRTIO_BLK_S_OK;
         } else {
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn vu_block_virtio_process_req(void *opaque)
         break;
     }
 
-    vu_block_req_complete(req);
+    vu_blk_req_complete(req);
     return;
 
 err:
-    free(elem);
+    free(req);
 }
 
-static void vu_block_process_vq(VuDev *vu_dev, int idx)
+static void vu_blk_process_vq(VuDev *vu_dev, int idx)
 {
     VuServer *server = container_of(vu_dev, VuServer, vu_dev);
     VuVirtq *vq = vu_get_queue(vu_dev, idx);
 
     while (1) {
-        VuBlockReq *req;
+        VuBlkReq *req;
 
-        req = vu_queue_pop(vu_dev, vq, sizeof(VuBlockReq));
+        req = vu_queue_pop(vu_dev, vq, sizeof(VuBlkReq));
         if (!req) {
             break;
         }
@@ -XXX,XX +XXX,XX @@ static void vu_block_process_vq(VuDev *vu_dev, int idx)
         req->vq = vq;
 
         Coroutine *co =
-            qemu_coroutine_create(vu_block_virtio_process_req, req);
+            qemu_coroutine_create(vu_blk_virtio_process_req, req);
         qemu_coroutine_enter(co);
     }
 }
 
-static void vu_block_queue_set_started(VuDev *vu_dev, int idx, bool started)
+static void vu_blk_queue_set_started(VuDev *vu_dev, int idx, bool started)
 {
     VuVirtq *vq;
 
     assert(vu_dev);
 
     vq = vu_get_queue(vu_dev, idx);
-    vu_set_queue_handler(vu_dev, vq, started ? vu_block_process_vq : NULL);
+    vu_set_queue_handler(vu_dev, vq, started ? vu_blk_process_vq : NULL);
 }
 
-static uint64_t vu_block_get_features(VuDev *dev)
+static uint64_t vu_blk_get_features(VuDev *dev)
 {
     uint64_t features;
     VuServer *server = container_of(dev, VuServer, vu_dev);
-    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
+    VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
     features = 1ull << VIRTIO_BLK_F_SIZE_MAX |
                1ull << VIRTIO_BLK_F_SEG_MAX |
                1ull << VIRTIO_BLK_F_TOPOLOGY |
@@ -XXX,XX +XXX,XX @@ static uint64_t vu_block_get_features(VuDev *dev)
                1ull << VIRTIO_RING_F_EVENT_IDX |
                1ull << VHOST_USER_F_PROTOCOL_FEATURES;
 
-    if (!vdev_blk->writable) {
+    if (!vexp->writable) {
         features |= 1ull << VIRTIO_BLK_F_RO;
     }
 
     return features;
 }
 
-static uint64_t vu_block_get_protocol_features(VuDev *dev)
+static uint64_t vu_blk_get_protocol_features(VuDev *dev)
 {
     return 1ull << VHOST_USER_PROTOCOL_F_CONFIG |
            1ull << VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD;
 }
 
 static int
-vu_block_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
+vu_blk_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
 {
+    /* TODO blkcfg must be little-endian for VIRTIO 1.0 */
     VuServer *server = container_of(vu_dev, VuServer, vu_dev);
-    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
-    memcpy(config, &vdev_blk->blkcfg, len);
-
+    VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
+    memcpy(config, &vexp->blkcfg, len);
     return 0;
 }
 
 static int
-vu_block_set_config(VuDev *vu_dev, const uint8_t *data,
+vu_blk_set_config(VuDev *vu_dev, const uint8_t *data,
                     uint32_t offset, uint32_t size, uint32_t flags)
 {
     VuServer *server = container_of(vu_dev, VuServer, vu_dev);
-    VuBlockDev *vdev_blk = get_vu_block_device_by_server(server);
+    VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
     uint8_t wce;
 
     /* don't support live migration */
@@ -XXX,XX +XXX,XX @@ vu_block_set_config(VuDev *vu_dev, const uint8_t *data,
     }
 
     wce = *data;
-    vdev_blk->blkcfg.wce = wce;
-    blk_set_enable_write_cache(vdev_blk->backend, wce);
+    vexp->blkcfg.wce = wce;
+    blk_set_enable_write_cache(vexp->export.blk, wce);
     return 0;
 }
 
@@ -XXX,XX +XXX,XX @@ vu_block_set_config(VuDev *vu_dev, const uint8_t *data,
  * of vu_process_message.
  *
  */
-static int vu_block_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
+static int vu_blk_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
 {
     if (vmsg->request == VHOST_USER_NONE) {
         dev->panic(dev, "disconnect");
@@ -XXX,XX +XXX,XX @@ static int vu_block_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
     return false;
 }
 
-static const VuDevIface vu_block_iface = {
-    .get_features          = vu_block_get_features,
-    .queue_set_started     = vu_block_queue_set_started,
-    .get_protocol_features = vu_block_get_protocol_features,
-    .get_config            = vu_block_get_config,
-    .set_config            = vu_block_set_config,
-    .process_msg           = vu_block_process_msg,
+static const VuDevIface vu_blk_iface = {
+    .get_features          = vu_blk_get_features,
+    .queue_set_started     = vu_blk_queue_set_started,
+    .get_protocol_features = vu_blk_get_protocol_features,
+    .get_config            = vu_blk_get_config,
+    .set_config            = vu_blk_set_config,
+    .process_msg           = vu_blk_process_msg,
 };
 
 static void blk_aio_attached(AioContext *ctx, void *opaque)
 {
-    VuBlockDev *vub_dev = opaque;
-    vhost_user_server_attach_aio_context(&vub_dev->vu_server, ctx);
+    VuBlkExport *vexp = opaque;
+    vhost_user_server_attach_aio_context(&vexp->vu_server, ctx);
 }
 
 static void blk_aio_detach(void *opaque)
 {
-    VuBlockDev *vub_dev = opaque;
-    vhost_user_server_detach_aio_context(&vub_dev->vu_server);
+    VuBlkExport *vexp = opaque;
+    vhost_user_server_detach_aio_context(&vexp->vu_server);
 }
 
 static void
-vu_block_initialize_config(BlockDriverState *bs,
+vu_blk_initialize_config(BlockDriverState *bs,
                            struct virtio_blk_config *config, uint32_t blk_size)
 {
     config->capacity = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
@@ -XXX,XX +XXX,XX @@ vu_block_initialize_config(BlockDriverState *bs,
     config->max_write_zeroes_seg = 1;
 }
 
-static VuBlockDev *vu_block_init(VuBlockDev *vu_block_device, Error **errp)
+static void vu_blk_exp_request_shutdown(BlockExport *exp)
 {
+    VuBlkExport *vexp = container_of(exp, VuBlkExport, export);
 
-    BlockBackend *blk;
-    Error *local_error = NULL;
-    const char *node_name = vu_block_device->node_name;
-    bool writable = vu_block_device->writable;
-    uint64_t perm = BLK_PERM_CONSISTENT_READ;
-    int ret;
-
-    AioContext *ctx;
-
-    BlockDriverState *bs = bdrv_lookup_bs(node_name, node_name, &local_error);
-
-    if (!bs) {
-        error_propagate(errp, local_error);
-        return NULL;
-    }
-
-    if (bdrv_is_read_only(bs)) {
-        writable = false;
-    }
-
-    if (writable) {
-        perm |= BLK_PERM_WRITE;
-    }
-
-    ctx = bdrv_get_aio_context(bs);
-    aio_context_acquire(ctx);
-    bdrv_invalidate_cache(bs, NULL);
-    aio_context_release(ctx);
-
-    /*
-     * Don't allow resize while the vhost user server is running,
-     * otherwise we don't care what happens with the node.
-     */
-    blk = blk_new(bdrv_get_aio_context(bs), perm,
-                  BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
-                  BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
-    ret = blk_insert_bs(blk, bs, errp);
-
-    if (ret < 0) {
-        goto fail;
-    }
-
-    blk_set_enable_write_cache(blk, false);
-
-    blk_set_allow_aio_context_change(blk, true);
-
-    vu_block_device->blkcfg.wce = 0;
-    vu_block_device->backend = blk;
-    if (!vu_block_device->blk_size) {
-        vu_block_device->blk_size = BDRV_SECTOR_SIZE;
-    }
-    vu_block_device->blkcfg.blk_size = vu_block_device->blk_size;
-    blk_set_guest_block_size(blk, vu_block_device->blk_size);
-    vu_block_initialize_config(bs, &vu_block_device->blkcfg,
-                                   vu_block_device->blk_size);
-    return vu_block_device;
-
-fail:
-    blk_unref(blk);
-    return NULL;
-}
-
-static void vu_block_deinit(VuBlockDev *vu_block_device)
-{
-    if (vu_block_device->backend) {
-        blk_remove_aio_context_notifier(vu_block_device->backend, blk_aio_attached,
-                                        blk_aio_detach, vu_block_device);
-    }
-
-    blk_unref(vu_block_device->backend);
-}
-
-static void vhost_user_blk_server_stop(VuBlockDev *vu_block_device)
-{
-    vhost_user_server_stop(&vu_block_device->vu_server);
-    vu_block_deinit(vu_block_device);
-}
-
-static void vhost_user_blk_server_start(VuBlockDev *vu_block_device,
-                                        Error **errp)
-{
-    AioContext *ctx;
-    SocketAddress *addr = vu_block_device->addr;
-
-    if (!vu_block_init(vu_block_device, errp)) {
-        return;
-    }
-
-    ctx = bdrv_get_aio_context(blk_bs(vu_block_device->backend));
-
-    if (!vhost_user_server_start(&vu_block_device->vu_server, addr, ctx,
-                                 VHOST_USER_BLK_MAX_QUEUES, &vu_block_iface,
-                                 errp)) {
-        goto error;
-    }
-
-    blk_add_aio_context_notifier(vu_block_device->backend, blk_aio_attached,
-                                 blk_aio_detach, vu_block_device);
-    vu_block_device->running = true;
-    return;
-
- error:
-    vu_block_deinit(vu_block_device);
-}
-
-static bool vu_prop_modifiable(VuBlockDev *vus, Error **errp)
-{
-    if (vus->running) {
-            error_setg(errp, "The property can't be modified "
-                       "while the server is running");
-            return false;
-    }
-    return true;
-}
-
-static void vu_set_node_name(Object *obj, const char *value, Error **errp)
-{
-    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
-
-    if (!vu_prop_modifiable(vus, errp)) {
-        return;
-    }
-
-    if (vus->node_name) {
-        g_free(vus->node_name);
-    }
-
-    vus->node_name = g_strdup(value);
-}
-
-static char *vu_get_node_name(Object *obj, Error **errp)
-{
-    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
-    return g_strdup(vus->node_name);
-}
-
-static void free_socket_addr(SocketAddress *addr)
-{
-        g_free(addr->u.q_unix.path);
-        g_free(addr);
-}
-
-static void vu_set_unix_socket(Object *obj, const char *value,
-                               Error **errp)
-{
-    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
-
-    if (!vu_prop_modifiable(vus, errp)) {
-        return;
-    }
-
-    if (vus->addr) {
-        free_socket_addr(vus->addr);
-    }
-
-    SocketAddress *addr = g_new0(SocketAddress, 1);
-    addr->type = SOCKET_ADDRESS_TYPE_UNIX;
-    addr->u.q_unix.path = g_strdup(value);
-    vus->addr = addr;
+    vhost_user_server_stop(&vexp->vu_server);
 }
 
-static char *vu_get_unix_socket(Object *obj, Error **errp)
+static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
+                             Error **errp)
 {
-    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
-    return g_strdup(vus->addr->u.q_unix.path);
-}
-
-static bool vu_get_block_writable(Object *obj, Error **errp)
-{
-    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
-    return vus->writable;
-}
-
-static void vu_set_block_writable(Object *obj, bool value, Error **errp)
-{
-    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
-
-    if (!vu_prop_modifiable(vus, errp)) {
-            return;
-    }
-
-    vus->writable = value;
-}
-
-static void vu_get_blk_size(Object *obj, Visitor *v, const char *name,
-                            void *opaque, Error **errp)
-{
-    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
-    uint32_t value = vus->blk_size;
-
-    visit_type_uint32(v, name, &value, errp);
-}
-
-static void vu_set_blk_size(Object *obj, Visitor *v, const char *name,
-                            void *opaque, Error **errp)
-{
-    VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj);
-
+    VuBlkExport *vexp = container_of(exp, VuBlkExport, export);
+    BlockExportOptionsVhostUserBlk *vu_opts = &opts->u.vhost_user_blk;
     Error *local_err = NULL;
-    uint32_t value;
+    uint64_t logical_block_size;
 
-    if (!vu_prop_modifiable(vus, errp)) {
-            return;
-    }
+    vexp->writable = opts->writable;
+    vexp->blkcfg.wce = 0;
 
-    visit_type_uint32(v, name, &value, &local_err);
-    if (local_err) {
-        goto out;
+    if (vu_opts->has_logical_block_size) {
+        logical_block_size = vu_opts->logical_block_size;
+    } else {
+        logical_block_size = BDRV_SECTOR_SIZE;
     }
-
-    check_block_size(object_get_typename(obj), name, value, &local_err);
+    check_block_size(exp->id, "logical-block-size", logical_block_size,
+                     &local_err);
     if (local_err) {
-        goto out;
+        error_propagate(errp, local_err);
+        return -EINVAL;
+    }
+    vexp->blk_size = logical_block_size;
+    blk_set_guest_block_size(exp->blk, logical_block_size);
+    vu_blk_initialize_config(blk_bs(exp->blk), &vexp->blkcfg,
+                               logical_block_size);
+
+    blk_set_allow_aio_context_change(exp->blk, true);
+    blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
+                                 vexp);
+
+    if (!vhost_user_server_start(&vexp->vu_server, vu_opts->addr, exp->ctx,
+                                 VHOST_USER_BLK_MAX_QUEUES, &vu_blk_iface,
+                                 errp)) {
+        blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
+                                        blk_aio_detach, vexp);
+        return -EADDRNOTAVAIL;
     }
 
-    vus->blk_size = value;
-
-out:
-    error_propagate(errp, local_err);
-}
-
-static void vhost_user_blk_server_instance_finalize(Object *obj)
-{
-    VuBlockDev *vub = VHOST_USER_BLK_SERVER(obj);
-
-    vhost_user_blk_server_stop(vub);
-
-    /*
-     * Unlike object_property_add_str, object_class_property_add_str
-     * doesn't have a release method. Thus manual memory freeing is
-     * needed.
-     */
-    free_socket_addr(vub->addr);
-    g_free(vub->node_name);
-}
-
-static void vhost_user_blk_server_complete(UserCreatable *obj, Error **errp)
-{
-    VuBlockDev *vub = VHOST_USER_BLK_SERVER(obj);
-
-    vhost_user_blk_server_start(vub, errp);
+    return 0;
 }
 
-static void vhost_user_blk_server_class_init(ObjectClass *klass,
-                                             void *class_data)
+static void vu_blk_exp_delete(BlockExport *exp)
 {
-    UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
-    ucc->complete = vhost_user_blk_server_complete;
-
-    object_class_property_add_bool(klass, "writable",
-                                   vu_get_block_writable,
-                                   vu_set_block_writable);
-
-    object_class_property_add_str(klass, "node-name",
-                                  vu_get_node_name,
-                                  vu_set_node_name);
-
-    object_class_property_add_str(klass, "unix-socket",
-                                  vu_get_unix_socket,
-                                  vu_set_unix_socket);
+    VuBlkExport *vexp = container_of(exp, VuBlkExport, export);
 
-    object_class_property_add(klass, "logical-block-size", "uint32",
-                              vu_get_blk_size, vu_set_blk_size,
-                              NULL, NULL);
+    blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
+                                    vexp);
 }
 
-static const TypeInfo vhost_user_blk_server_info = {
-    .name = TYPE_VHOST_USER_BLK_SERVER,
-    .parent = TYPE_OBJECT,
-    .instance_size = sizeof(VuBlockDev),
-    .instance_finalize = vhost_user_blk_server_instance_finalize,
-    .class_init = vhost_user_blk_server_class_init,
-    .interfaces = (InterfaceInfo[]) {
-        {TYPE_USER_CREATABLE},
-        {}
-    },
+const BlockExportDriver blk_exp_vhost_user_blk = {
+    .type               = BLOCK_EXPORT_TYPE_VHOST_USER_BLK,
+    .instance_size      = sizeof(VuBlkExport),
+    .create             = vu_blk_exp_create,
+    .delete             = vu_blk_exp_delete,
+    .request_shutdown   = vu_blk_exp_request_shutdown,
 };
-
-static void vhost_user_blk_server_register_types(void)
-{
-    type_register_static(&vhost_user_blk_server_info);
-}
-
-type_init(vhost_user_blk_server_register_types)
diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
index XXXXXXX..XXXXXXX 100644
--- a/util/vhost-user-server.c
+++ b/util/vhost-user-server.c
@@ -XXX,XX +XXX,XX @@ bool vhost_user_server_start(VuServer *server,
                              Error **errp)
 {
     QEMUBH *bh;
-    QIONetListener *listener = qio_net_listener_new();
+    QIONetListener *listener;
+
+    if (socket_addr->type != SOCKET_ADDRESS_TYPE_UNIX &&
+        socket_addr->type != SOCKET_ADDRESS_TYPE_FD) {
+        error_setg(errp, "Only socket address types 'unix' and 'fd' are supported");
+        return false;
+    }
+
+    listener = qio_net_listener_new();
     if (qio_net_listener_open_sync(listener, socket_addr, 1,
                                    errp) < 0) {
         object_unref(OBJECT(listener));
diff --git a/block/export/meson.build b/block/export/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/block/export/meson.build
+++ b/block/export/meson.build
@@ -1 +1,2 @@
 block_ss.add(files('export.c'))
+block_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-blk-server.c', '../../contrib/libvhost-user/libvhost-user.c'))
diff --git a/block/meson.build b/block/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/block/meson.build
+++ b/block/meson.build
@@ -XXX,XX +XXX,XX @@ block_ss.add(when: 'CONFIG_WIN32', if_true: files('file-win32.c', 'win32-aio.c')
 block_ss.add(when: 'CONFIG_POSIX', if_true: [files('file-posix.c'), coref, iokit])
 block_ss.add(when: 'CONFIG_LIBISCSI', if_true: files('iscsi-opts.c'))
 block_ss.add(when: 'CONFIG_LINUX', if_true: files('nvme.c'))
-block_ss.add(when: 'CONFIG_LINUX', if_true: files('export/vhost-user-blk-server.c', '../contrib/libvhost-user/libvhost-user.c'))
 block_ss.add(when: 'CONFIG_REPLICATION', if_true: files('replication.c'))
 block_ss.add(when: 'CONFIG_SHEEPDOG', if_true: files('sheepdog.c'))
 block_ss.add(when: ['CONFIG_LINUX_AIO', libaio], if_true: files('linux-aio.c'))
-- 
2.26.2

Headers used by other subsystems are located in include/. Also add the
vhost-user-server and vhost-user-blk-server headers to MAINTAINERS.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200924151549.913737-13-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS                                | 4 +++-
 {util => include/qemu}/vhost-user-server.h | 0
 block/export/vhost-user-blk-server.c       | 2 +-
 util/vhost-user-server.c                   | 2 +-
 4 files changed, 5 insertions(+), 3 deletions(-)
 rename {util => include/qemu}/vhost-user-server.h (100%)

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ Vhost-user block device backend server
 M: Coiby Xu <Coiby.Xu@gmail.com>
 S: Maintained
 F: block/export/vhost-user-blk-server.c
-F: util/vhost-user-server.c
+F: block/export/vhost-user-blk-server.h
+F: include/qemu/vhost-user-server.h
 F: tests/qtest/libqos/vhost-user-blk.c
+F: util/vhost-user-server.c
 
 Replication
 M: Wen Congyang <wencongyang2@huawei.com>
diff --git a/util/vhost-user-server.h b/include/qemu/vhost-user-server.h
similarity index 100%
rename from util/vhost-user-server.h
rename to include/qemu/vhost-user-server.h
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index XXXXXXX..XXXXXXX 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -XXX,XX +XXX,XX @@
 #include "block/block.h"
 #include "contrib/libvhost-user/libvhost-user.h"
 #include "standard-headers/linux/virtio_blk.h"
-#include "util/vhost-user-server.h"
+#include "qemu/vhost-user-server.h"
 #include "vhost-user-blk-server.h"
 #include "qapi/error.h"
 #include "qom/object_interfaces.h"
diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
index XXXXXXX..XXXXXXX 100644
--- a/util/vhost-user-server.c
+++ b/util/vhost-user-server.c
@@ -XXX,XX +XXX,XX @@
  */
 #include "qemu/osdep.h"
 #include "qemu/main-loop.h"
+#include "qemu/vhost-user-server.h"
 #include "block/aio-wait.h"
-#include "vhost-user-server.h"
 
 /*
  * Theory of operation:
-- 
2.26.2

Don't compile contrib/libvhost-user/libvhost-user.c again. Instead build
the static library once and then reuse it throughout QEMU.

Also switch from CONFIG_LINUX to CONFIG_VHOST_USER, which is what the
vhost-user tools (vhost-user-gpu, etc) do.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200924151549.913737-14-stefanha@redhat.com
[Added CONFIG_LINUX again because libvhost-user doesn't build on macOS.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/export/export.c             | 8 ++++----
 block/export/meson.build          | 2 +-
 contrib/libvhost-user/meson.build | 1 +
 meson.build                       | 6 +++++-
 util/meson.build                  | 4 +++-
 5 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/block/export/export.c b/block/export/export.c
index XXXXXXX..XXXXXXX 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -XXX,XX +XXX,XX @@
 #include "sysemu/block-backend.h"
 #include "block/export.h"
 #include "block/nbd.h"
-#if CONFIG_LINUX
-#include "block/export/vhost-user-blk-server.h"
-#endif
 #include "qapi/error.h"
 #include "qapi/qapi-commands-block-export.h"
 #include "qapi/qapi-events-block-export.h"
 #include "qemu/id.h"
+#ifdef CONFIG_VHOST_USER
+#include "vhost-user-blk-server.h"
+#endif
 
 static const BlockExportDriver *blk_exp_drivers[] = {
     &blk_exp_nbd,
-#if CONFIG_LINUX
+#ifdef CONFIG_VHOST_USER
     &blk_exp_vhost_user_blk,
 #endif
 };
diff --git a/block/export/meson.build b/block/export/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/block/export/meson.build
+++ b/block/export/meson.build
@@ -XXX,XX +XXX,XX @@
 block_ss.add(files('export.c'))
-block_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-blk-server.c', '../../contrib/libvhost-user/libvhost-user.c'))
+block_ss.add(when: ['CONFIG_LINUX', 'CONFIG_VHOST_USER'], if_true: files('vhost-user-blk-server.c'))
diff --git a/contrib/libvhost-user/meson.build b/contrib/libvhost-user/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/contrib/libvhost-user/meson.build
+++ b/contrib/libvhost-user/meson.build
@@ -XXX,XX +XXX,XX @@
 libvhost_user = static_library('vhost-user',
                                files('libvhost-user.c', 'libvhost-user-glib.c'),
                                build_by_default: false)
+vhost_user = declare_dependency(link_with: libvhost_user)
diff --git a/meson.build b/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/meson.build
+++ b/meson.build
@@ -XXX,XX +XXX,XX @@ trace_events_subdirs += [
   'util',
 ]
 
+vhost_user = not_found
+if 'CONFIG_VHOST_USER' in config_host
+  subdir('contrib/libvhost-user')
+endif
+
 subdir('qapi')
 subdir('qobject')
 subdir('stubs')
@@ -XXX,XX +XXX,XX @@ if have_tools
              install: true)
 
   if 'CONFIG_VHOST_USER' in config_host
-    subdir('contrib/libvhost-user')
     subdir('contrib/vhost-user-blk')
     subdir('contrib/vhost-user-gpu')
     subdir('contrib/vhost-user-input')
diff --git a/util/meson.build b/util/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/util/meson.build
+++ b/util/meson.build
@@ -XXX,XX +XXX,XX @@ if have_block
   util_ss.add(files('main-loop.c'))
   util_ss.add(files('nvdimm-utils.c'))
   util_ss.add(files('qemu-coroutine.c', 'qemu-coroutine-lock.c', 'qemu-coroutine-io.c'))
-  util_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-server.c'))
+  util_ss.add(when: ['CONFIG_LINUX', 'CONFIG_VHOST_USER'], if_true: [
+    files('vhost-user-server.c'), vhost_user
+  ])
   util_ss.add(files('block-helpers.c'))
   util_ss.add(files('qemu-coroutine-sleep.c'))
   util_ss.add(files('qemu-co-shared-resource.c'))
-- 
2.26.2

Introduce libblkdev.fa to avoid recompiling blockdev_ss twice.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200929125516.186715-3-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 meson.build                | 12 ++++++++++--
 storage-daemon/meson.build |  3 +--
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/meson.build b/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/meson.build
+++ b/meson.build
@@ -XXX,XX +XXX,XX @@ blockdev_ss.add(files(
 # os-win32.c does not
 blockdev_ss.add(when: 'CONFIG_POSIX', if_true: files('os-posix.c'))
 softmmu_ss.add(when: 'CONFIG_WIN32', if_true: [files('os-win32.c')])
-softmmu_ss.add_all(blockdev_ss)
 
 common_ss.add(files('cpus-common.c'))
 
@@ -XXX,XX +XXX,XX @@ block = declare_dependency(link_whole: [libblock],
                            link_args: '@block.syms',
                            dependencies: [crypto, io])
 
+blockdev_ss = blockdev_ss.apply(config_host, strict: false)
+libblockdev = static_library('blockdev', blockdev_ss.sources() + genh,
+                             dependencies: blockdev_ss.dependencies(),
+                             name_suffix: 'fa',
+                             build_by_default: false)
+
+blockdev = declare_dependency(link_whole: [libblockdev],
+                              dependencies: [block])
+
 qmp_ss = qmp_ss.apply(config_host, strict: false)
 libqmp = static_library('qmp', qmp_ss.sources() + genh,
                         dependencies: qmp_ss.dependencies(),
@@ -XXX,XX +XXX,XX @@ foreach m : block_mods + softmmu_mods
                 install_dir: config_host['qemu_moddir'])
 endforeach
 
-softmmu_ss.add(authz, block, chardev, crypto, io, qmp)
+softmmu_ss.add(authz, blockdev, chardev, crypto, io, qmp)
 common_ss.add(qom, qemuutil)
 
 common_ss.add_all(when: 'CONFIG_SOFTMMU', if_true: [softmmu_ss])
diff --git a/storage-daemon/meson.build b/storage-daemon/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/storage-daemon/meson.build
+++ b/storage-daemon/meson.build
@@ -XXX,XX +XXX,XX @@
 qsd_ss = ss.source_set()
 qsd_ss.add(files('qemu-storage-daemon.c'))
-qsd_ss.add(block, chardev, qmp, qom, qemuutil)
-qsd_ss.add_all(blockdev_ss)
+qsd_ss.add(blockdev, chardev, qmp, qom, qemuutil)
 
 subdir('qapi')
 
-- 
2.26.2

Block exports are used by softmmu, qemu-storage-daemon, and qemu-nbd.
They are not used by other programs and are not otherwise needed in
libblock.

Undo the recent move of blockdev-nbd.c from blockdev_ss into block_ss.
Since bdrv_close_all() (libblock) calls blk_exp_close_all()
(libblockdev) a stub function is required..

Make qemu-nbd.c use signal handling utility functions instead of
duplicating the code. This helps because os-posix.c is in libblockdev
and it depends on a qemu_system_killed() symbol that qemu-nbd.c lacks.
Once we use the signal handling utility functions we also end up
providing the necessary symbol.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20200929125516.186715-4-stefanha@redhat.com
[Fixed s/ndb/nbd/ typo in commit description as suggested by Eric Blake
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 qemu-nbd.c                | 21 ++++++++-------------
 stubs/blk-exp-close-all.c |  7 +++++++
 block/export/meson.build  |  4 ++--
 meson.build               |  4 ++--
 nbd/meson.build           |  2 ++
 stubs/meson.build         |  1 +
 6 files changed, 22 insertions(+), 17 deletions(-)
 create mode 100644 stubs/blk-exp-close-all.c

diff --git a/qemu-nbd.c b/qemu-nbd.c
index XXXXXXX..XXXXXXX 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -XXX,XX +XXX,XX @@
 #include "qapi/error.h"
 #include "qemu/cutils.h"
 #include "sysemu/block-backend.h"
+#include "sysemu/runstate.h" /* for qemu_system_killed() prototype */
 #include "block/block_int.h"
 #include "block/nbd.h"
 #include "qemu/main-loop.h"
@@ -XXX,XX +XXX,XX @@ QEMU_COPYRIGHT "\n"
 }
 
 #ifdef CONFIG_POSIX
-static void termsig_handler(int signum)
+/*
+ * The client thread uses SIGTERM to interrupt the server.  A signal
+ * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
+ */
+void qemu_system_killed(int signum, pid_t pid)
 {
     qatomic_cmpxchg(&state, RUNNING, TERMINATE);
     qemu_notify_event();
@@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv)
     BlockExportOptions *export_opts;
 
 #ifdef CONFIG_POSIX
-    /*
-     * Exit gracefully on various signals, which includes SIGTERM used
-     * by 'qemu-nbd -v -c'.
-     */
-    struct sigaction sa_sigterm;
-    memset(&sa_sigterm, 0, sizeof(sa_sigterm));
-    sa_sigterm.sa_handler = termsig_handler;
-    sigaction(SIGTERM, &sa_sigterm, NULL);
-    sigaction(SIGINT, &sa_sigterm, NULL);
-    sigaction(SIGHUP, &sa_sigterm, NULL);
-
-    signal(SIGPIPE, SIG_IGN);
+    os_setup_early_signal_handling();
+    os_setup_signal_handling();
 #endif
 
     socket_init();
diff --git a/stubs/blk-exp-close-all.c b/stubs/blk-exp-close-all.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/stubs/blk-exp-close-all.c
@@ -XXX,XX +XXX,XX @@
+#include "qemu/osdep.h"
+#include "block/export.h"
+
+/* Only used in programs that support block exports (libblockdev.fa) */
+void blk_exp_close_all(void)
+{
+}
diff --git a/block/export/meson.build b/block/export/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/block/export/meson.build
+++ b/block/export/meson.build
@@ -XXX,XX +XXX,XX @@
-block_ss.add(files('export.c'))
-block_ss.add(when: ['CONFIG_LINUX', 'CONFIG_VHOST_USER'], if_true: files('vhost-user-blk-server.c'))
+blockdev_ss.add(files('export.c'))
+blockdev_ss.add(when: ['CONFIG_LINUX', 'CONFIG_VHOST_USER'], if_true: files('vhost-user-blk-server.c'))
diff --git a/meson.build b/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/meson.build
+++ b/meson.build
@@ -XXX,XX +XXX,XX @@ subdir('dump')
 
 block_ss.add(files(
   'block.c',
-  'blockdev-nbd.c',
   'blockjob.c',
   'job.c',
   'qemu-io-cmds.c',
@@ -XXX,XX +XXX,XX @@ subdir('block')
 
 blockdev_ss.add(files(
   'blockdev.c',
+  'blockdev-nbd.c',
   'iothread.c',
   'job-qmp.c',
 ))
@@ -XXX,XX +XXX,XX @@ if have_tools
   qemu_io = executable('qemu-io', files('qemu-io.c'),
              dependencies: [block, qemuutil], install: true)
   qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
-               dependencies: [block, qemuutil], install: true)
+               dependencies: [blockdev, qemuutil], install: true)
 
   subdir('storage-daemon')
   subdir('contrib/rdmacm-mux')
diff --git a/nbd/meson.build b/nbd/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/nbd/meson.build
+++ b/nbd/meson.build
@@ -XXX,XX +XXX,XX @@
 block_ss.add(files(
   'client.c',
   'common.c',
+))
+blockdev_ss.add(files(
   'server.c',
 ))
diff --git a/stubs/meson.build b/stubs/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/stubs/meson.build
+++ b/stubs/meson.build
@@ -XXX,XX +XXX,XX @@
 stub_ss.add(files('arch_type.c'))
 stub_ss.add(files('bdrv-next-monitor-owned.c'))
 stub_ss.add(files('blk-commit-all.c'))
+stub_ss.add(files('blk-exp-close-all.c'))
 stub_ss.add(files('blockdev-close-all-bdrv-states.c'))
 stub_ss.add(files('change-state-handler.c'))
 stub_ss.add(files('cmos.c'))
-- 
2.26.2

Make it possible to specify the iothread where the export will run. By
default the block node can be moved to other AioContexts later and the
export will follow. The fixed-iothread option forces strict behavior
that prevents changing AioContext while the export is active. See the
QAPI docs for details.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200929125516.186715-5-stefanha@redhat.com
[Fix stray '#' character in block-export.json and add missing "(since:
5.2)" as suggested by Eric Blake.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 qapi/block-export.json               | 11 ++++++++++
 block/export/export.c                | 31 +++++++++++++++++++++++++++-
 block/export/vhost-user-blk-server.c |  5 ++++-
 nbd/server.c                         |  2 --
 4 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/qapi/block-export.json b/qapi/block-export.json
index XXXXXXX..XXXXXXX 100644
--- a/qapi/block-export.json
+++ b/qapi/block-export.json
@@ -XXX,XX +XXX,XX @@
 #                export before completion is signalled. (since: 5.2;
 #                default: false)
 #
+# @iothread: The name of the iothread object where the export will run. The
+#            default is to use the thread currently associated with the
+#            block node. (since: 5.2)
+#
+# @fixed-iothread: True prevents the block node from being moved to another
+#                  thread while the export is active. If true and @iothread is
+#                  given, export creation fails if the block node cannot be
+#                  moved to the iothread. The default is false. (since: 5.2)
+#
 # Since: 4.2
 ##
 { 'union': 'BlockExportOptions',
   'base': { 'type': 'BlockExportType',
             'id': 'str',
+	    '*fixed-iothread': 'bool',
+	    '*iothread': 'str',
             'node-name': 'str',
             '*writable': 'bool',
             '*writethrough': 'bool' },
diff --git a/block/export/export.c b/block/export/export.c
index XXXXXXX..XXXXXXX 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -XXX,XX +XXX,XX @@
 
 #include "block/block.h"
 #include "sysemu/block-backend.h"
+#include "sysemu/iothread.h"
 #include "block/export.h"
 #include "block/nbd.h"
 #include "qapi/error.h"
@@ -XXX,XX +XXX,XX @@ static const BlockExportDriver *blk_exp_find_driver(BlockExportType type)
 
 BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
 {
+    bool fixed_iothread = export->has_fixed_iothread && export->fixed_iothread;
     const BlockExportDriver *drv;
     BlockExport *exp = NULL;
     BlockDriverState *bs;
-    BlockBackend *blk;
+    BlockBackend *blk = NULL;
     AioContext *ctx;
     uint64_t perm;
     int ret;
@@ -XXX,XX +XXX,XX @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
     ctx = bdrv_get_aio_context(bs);
     aio_context_acquire(ctx);
 
+    if (export->has_iothread) {
+        IOThread *iothread;
+        AioContext *new_ctx;
+
+        iothread = iothread_by_id(export->iothread);
+        if (!iothread) {
+            error_setg(errp, "iothread \"%s\" not found", export->iothread);
+            goto fail;
+        }
+
+        new_ctx = iothread_get_aio_context(iothread);
+
+        ret = bdrv_try_set_aio_context(bs, new_ctx, errp);
+        if (ret == 0) {
+            aio_context_release(ctx);
+            aio_context_acquire(new_ctx);
+            ctx = new_ctx;
+        } else if (fixed_iothread) {
+            goto fail;
+        }
+    }
+
     /*
      * Block exports are used for non-shared storage migration. Make sure
      * that BDRV_O_INACTIVE is cleared and the image is ready for write
@@ -XXX,XX +XXX,XX @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
     }
 
     blk = blk_new(ctx, perm, BLK_PERM_ALL);
+
+    if (!fixed_iothread) {
+        blk_set_allow_aio_context_change(blk, true);
+    }
+
     ret = blk_insert_bs(blk, bs, errp);
     if (ret < 0) {
         goto fail;
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index XXXXXXX..XXXXXXX 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -XXX,XX +XXX,XX @@ static const VuDevIface vu_blk_iface = {
 static void blk_aio_attached(AioContext *ctx, void *opaque)
 {
     VuBlkExport *vexp = opaque;
+
+    vexp->export.ctx = ctx;
     vhost_user_server_attach_aio_context(&vexp->vu_server, ctx);
 }
 
 static void blk_aio_detach(void *opaque)
 {
     VuBlkExport *vexp = opaque;
+
     vhost_user_server_detach_aio_context(&vexp->vu_server);
+    vexp->export.ctx = NULL;
 }
 
 static void
@@ -XXX,XX +XXX,XX @@ static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
     vu_blk_initialize_config(blk_bs(exp->blk), &vexp->blkcfg,
                                logical_block_size);
 
-    blk_set_allow_aio_context_change(exp->blk, true);
     blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
                                  vexp);
 
diff --git a/nbd/server.c b/nbd/server.c
index XXXXXXX..XXXXXXX 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -XXX,XX +XXX,XX @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args,
         return ret;
     }
 
-    blk_set_allow_aio_context_change(blk, true);
-
     QTAILQ_INIT(&exp->clients);
     exp->name = g_strdup(arg->name);
     exp->description = g_strdup(arg->description);
-- 
2.26.2

Allow the number of queues to be configured using --export
vhost-user-blk,num-queues=N. This setting should match the QEMU --device
vhost-user-blk-pci,num-queues=N setting but QEMU vhost-user-blk.c lowers
its own value if the vhost-user-blk backend offers fewer queues than
QEMU.

The vhost-user-blk-server.c code is already capable of multi-queue. All
virtqueue processing runs in the same AioContext. No new locking is
needed.

Add the num-queues=N option and set the VIRTIO_BLK_F_MQ feature bit.
Note that the feature bit only announces the presence of the num_queues
configuration space field. It does not promise that there is more than 1
virtqueue, so we can set it unconditionally.

I tested multi-queue by running a random read fio test with numjobs=4 on
an -smp 4 guest. After the benchmark finished the guest /proc/interrupts
file showed activity on all 4 virtio-blk MSI-X. The /sys/block/vda/mq/
directory shows that Linux blk-mq has 4 queues configured.

An automated test is included in the next commit.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20201001144604.559733-2-stefanha@redhat.com
[Fixed accidental tab characters as suggested by Markus Armbruster
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 qapi/block-export.json               | 10 +++++++---
 block/export/vhost-user-blk-server.c | 24 ++++++++++++++++++------
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/qapi/block-export.json b/qapi/block-export.json
index XXXXXXX..XXXXXXX 100644
--- a/qapi/block-export.json
+++ b/qapi/block-export.json
@@ -XXX,XX +XXX,XX @@
 #        SocketAddress types are supported. Passed fds must be UNIX domain
 #        sockets.
 # @logical-block-size: Logical block size in bytes. Defaults to 512 bytes.
+# @num-queues: Number of request virtqueues. Must be greater than 0. Defaults
+#              to 1.
 #
 # Since: 5.2
 ##
 { 'struct': 'BlockExportOptionsVhostUserBlk',
-  'data': { 'addr': 'SocketAddress', '*logical-block-size': 'size' } }
+  'data': { 'addr': 'SocketAddress',
+	    '*logical-block-size': 'size',
+            '*num-queues': 'uint16'} }
 
 ##
 # @NbdServerAddOptions:
@@ -XXX,XX +XXX,XX @@
 { 'union': 'BlockExportOptions',
   'base': { 'type': 'BlockExportType',
             'id': 'str',
-	    '*fixed-iothread': 'bool',
-	    '*iothread': 'str',
+            '*fixed-iothread': 'bool',
+            '*iothread': 'str',
             'node-name': 'str',
             '*writable': 'bool',
             '*writethrough': 'bool' },
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index XXXXXXX..XXXXXXX 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -XXX,XX +XXX,XX @@
 #include "util/block-helpers.h"
 
 enum {
-    VHOST_USER_BLK_MAX_QUEUES = 1,
+    VHOST_USER_BLK_NUM_QUEUES_DEFAULT = 1,
 };
 struct virtio_blk_inhdr {
     unsigned char status;
@@ -XXX,XX +XXX,XX @@ static uint64_t vu_blk_get_features(VuDev *dev)
                1ull << VIRTIO_BLK_F_DISCARD |
                1ull << VIRTIO_BLK_F_WRITE_ZEROES |
                1ull << VIRTIO_BLK_F_CONFIG_WCE |
+               1ull << VIRTIO_BLK_F_MQ |
                1ull << VIRTIO_F_VERSION_1 |
                1ull << VIRTIO_RING_F_INDIRECT_DESC |
                1ull << VIRTIO_RING_F_EVENT_IDX |
@@ -XXX,XX +XXX,XX @@ static void blk_aio_detach(void *opaque)
 
 static void
 vu_blk_initialize_config(BlockDriverState *bs,
-                           struct virtio_blk_config *config, uint32_t blk_size)
+                         struct virtio_blk_config *config,
+                         uint32_t blk_size,
+                         uint16_t num_queues)
 {
     config->capacity = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
     config->blk_size = blk_size;
@@ -XXX,XX +XXX,XX @@ vu_blk_initialize_config(BlockDriverState *bs,
     config->seg_max = 128 - 2;
     config->min_io_size = 1;
     config->opt_io_size = 1;
-    config->num_queues = VHOST_USER_BLK_MAX_QUEUES;
+    config->num_queues = num_queues;
     config->max_discard_sectors = 32768;
     config->max_discard_seg = 1;
     config->discard_sector_alignment = config->blk_size >> 9;
@@ -XXX,XX +XXX,XX @@ static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
     BlockExportOptionsVhostUserBlk *vu_opts = &opts->u.vhost_user_blk;
     Error *local_err = NULL;
     uint64_t logical_block_size;
+    uint16_t num_queues = VHOST_USER_BLK_NUM_QUEUES_DEFAULT;
 
     vexp->writable = opts->writable;
     vexp->blkcfg.wce = 0;
@@ -XXX,XX +XXX,XX @@ static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
     }
     vexp->blk_size = logical_block_size;
     blk_set_guest_block_size(exp->blk, logical_block_size);
+
+    if (vu_opts->has_num_queues) {
+        num_queues = vu_opts->num_queues;
+    }
+    if (num_queues == 0) {
+        error_setg(errp, "num-queues must be greater than 0");
+        return -EINVAL;
+    }
+
     vu_blk_initialize_config(blk_bs(exp->blk), &vexp->blkcfg,
-                               logical_block_size);
+                             logical_block_size, num_queues);
 
     blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
                                  vexp);
 
     if (!vhost_user_server_start(&vexp->vu_server, vu_opts->addr, exp->ctx,
-                                 VHOST_USER_BLK_MAX_QUEUES, &vu_blk_iface,
-                                 errp)) {
+                                 num_queues, &vu_blk_iface, errp)) {
         blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
                                         blk_aio_detach, vexp);
         return -EADDRNOTAVAIL;
-- 
2.26.2

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

bdrv_co_block_status_above has several design problems with handling
short backing files:

1. With want_zeros=true, it may return ret with BDRV_BLOCK_ZERO but
without BDRV_BLOCK_ALLOCATED flag, when actually short backing file
which produces these after-EOF zeros is inside requested backing
sequence.

2. With want_zero=false, it may return pnum=0 prior to actual EOF,
because of EOF of short backing file.

Fix these things, making logic about short backing files clearer.

With fixed bdrv_block_status_above we also have to improve is_zero in
qcow2 code, otherwise iotest 154 will fail, because with this patch we
stop to merge zeros of different types (produced by fully unallocated
in the whole backing chain regions vs produced by short backing files).

Note also, that this patch leaves for another day the general problem
around block-status: misuse of BDRV_BLOCK_ALLOCATED as is-fs-allocated
vs go-to-backing.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20200924194003.22080-2-vsementsov@virtuozzo.com
[Fix s/comes/come/ as suggested by Eric Blake
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/io.c    | 68 ++++++++++++++++++++++++++++++++++++++++-----------
 block/qcow2.c | 16 ++++++++++--
 2 files changed, 68 insertions(+), 16 deletions(-)

diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
                                   int64_t *map,
                                   BlockDriverState **file)
 {
+    int ret;
     BlockDriverState *p;
-    int ret = 0;
-    bool first = true;
+    int64_t eof = 0;
 
     assert(bs != base);
-    for (p = bs; p != base; p = bdrv_filter_or_cow_bs(p)) {
+
+    ret = bdrv_co_block_status(bs, want_zero, offset, bytes, pnum, map, file);
+    if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED) {
+        return ret;
+    }
+
+    if (ret & BDRV_BLOCK_EOF) {
+        eof = offset + *pnum;
+    }
+
+    assert(*pnum <= bytes);
+    bytes = *pnum;
+
+    for (p = bdrv_filter_or_cow_bs(bs); p != base;
+         p = bdrv_filter_or_cow_bs(p))
+    {
         ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
                                    file);
         if (ret < 0) {
-            break;
+            return ret;
         }
-        if (ret & BDRV_BLOCK_ZERO && ret & BDRV_BLOCK_EOF && !first) {
+        if (*pnum == 0) {
             /*
-             * Reading beyond the end of the file continues to read
-             * zeroes, but we can only widen the result to the
-             * unallocated length we learned from an earlier
-             * iteration.
+             * The top layer deferred to this layer, and because this layer is
+             * short, any zeroes that we synthesize beyond EOF behave as if they
+             * were allocated at this layer.
+             *
+             * We don't include BDRV_BLOCK_EOF into ret, as upper layer may be
+             * larger. We'll add BDRV_BLOCK_EOF if needed at function end, see
+             * below.
              */
+            assert(ret & BDRV_BLOCK_EOF);
             *pnum = bytes;
+            if (file) {
+                *file = p;
+            }
+            ret = BDRV_BLOCK_ZERO | BDRV_BLOCK_ALLOCATED;
+            break;
         }
-        if (ret & (BDRV_BLOCK_ZERO | BDRV_BLOCK_DATA)) {
+        if (ret & BDRV_BLOCK_ALLOCATED) {
+            /*
+             * We've found the node and the status, we must break.
+             *
+             * Drop BDRV_BLOCK_EOF, as it's not for upper layer, which may be
+             * larger. We'll add BDRV_BLOCK_EOF if needed at function end, see
+             * below.
+             */
+            ret &= ~BDRV_BLOCK_EOF;
             break;
         }
-        /* [offset, pnum] unallocated on this layer, which could be only
-         * the first part of [offset, bytes].  */
-        bytes = MIN(bytes, *pnum);
-        first = false;
+
+        /*
+         * OK, [offset, offset + *pnum) region is unallocated on this layer,
+         * let's continue the diving.
+         */
+        assert(*pnum <= bytes);
+        bytes = *pnum;
+    }
+
+    if (offset + *pnum == eof) {
+        ret |= BDRV_BLOCK_EOF;
     }
+
     return ret;
 }
 
diff --git a/block/qcow2.c b/block/qcow2.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -XXX,XX +XXX,XX @@ static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)
     if (!bytes) {
         return true;
     }
-    res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL);
-    return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes;
+
+    /*
+     * bdrv_block_status_above doesn't merge different types of zeros, for
+     * example, zeros which come from the region which is unallocated in
+     * the whole backing chain, and zeros which come because of a short
+     * backing file. So, we need a loop.
+     */
+    do {
+        res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL);
+        offset += nr;
+        bytes -= nr;
+    } while (res >= 0 && (res & BDRV_BLOCK_ZERO) && nr && bytes);
+
+    return res >= 0 && (res & BDRV_BLOCK_ZERO) && bytes == 0;
 }
 
 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
-- 
2.26.2

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

In order to reuse bdrv_common_block_status_above in
bdrv_is_allocated_above, let's support include_base parameter.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20200924194003.22080-3-vsementsov@virtuozzo.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/coroutines.h |  2 ++
 block/io.c         | 21 ++++++++++++++-------
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/block/coroutines.h b/block/coroutines.h
index XXXXXXX..XXXXXXX 100644
--- a/block/coroutines.h
+++ b/block/coroutines.h
@@ -XXX,XX +XXX,XX @@ bdrv_pwritev(BdrvChild *child, int64_t offset, unsigned int bytes,
 int coroutine_fn
 bdrv_co_common_block_status_above(BlockDriverState *bs,
                                   BlockDriverState *base,
+                                  bool include_base,
                                   bool want_zero,
                                   int64_t offset,
                                   int64_t bytes,
@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
 int generated_co_wrapper
 bdrv_common_block_status_above(BlockDriverState *bs,
                                BlockDriverState *base,
+                               bool include_base,
                                bool want_zero,
                                int64_t offset,
                                int64_t bytes,
diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ early_out:
 int coroutine_fn
 bdrv_co_common_block_status_above(BlockDriverState *bs,
                                   BlockDriverState *base,
+                                  bool include_base,
                                   bool want_zero,
                                   int64_t offset,
                                   int64_t bytes,
@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
     BlockDriverState *p;
     int64_t eof = 0;
 
-    assert(bs != base);
+    assert(include_base || bs != base);
+    assert(!include_base || base); /* Can't include NULL base */
 
     ret = bdrv_co_block_status(bs, want_zero, offset, bytes, pnum, map, file);
-    if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED) {
+    if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED || bs == base) {
         return ret;
     }
 
@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
     assert(*pnum <= bytes);
     bytes = *pnum;
 
-    for (p = bdrv_filter_or_cow_bs(bs); p != base;
+    for (p = bdrv_filter_or_cow_bs(bs); include_base || p != base;
          p = bdrv_filter_or_cow_bs(p))
     {
         ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
             break;
         }
 
+        if (p == base) {
+            assert(include_base);
+            break;
+        }
+
         /*
          * OK, [offset, offset + *pnum) region is unallocated on this layer,
          * let's continue the diving.
@@ -XXX,XX +XXX,XX @@ int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
                             int64_t offset, int64_t bytes, int64_t *pnum,
                             int64_t *map, BlockDriverState **file)
 {
-    return bdrv_common_block_status_above(bs, base, true, offset, bytes,
+    return bdrv_common_block_status_above(bs, base, false, true, offset, bytes,
                                           pnum, map, file);
 }
 
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
     int ret;
     int64_t dummy;
 
-    ret = bdrv_common_block_status_above(bs, bdrv_filter_or_cow_bs(bs), false,
-                                         offset, bytes, pnum ? pnum : &dummy,
-                                         NULL, NULL);
+    ret = bdrv_common_block_status_above(bs, bs, true, false, offset,
+                                         bytes, pnum ? pnum : &dummy, NULL,
+                                         NULL);
     if (ret < 0) {
         return ret;
     }
-- 
2.26.2

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

We are going to reuse bdrv_common_block_status_above in
bdrv_is_allocated_above. bdrv_is_allocated_above may be called with
include_base == false and still bs == base (for ex. from img_rebase()).

So, support this corner case.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20200924194003.22080-4-vsementsov@virtuozzo.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/io.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
     BlockDriverState *p;
     int64_t eof = 0;
 
-    assert(include_base || bs != base);
     assert(!include_base || base); /* Can't include NULL base */
 
+    if (!include_base && bs == base) {
+        *pnum = bytes;
+        return 0;
+    }
+
     ret = bdrv_co_block_status(bs, want_zero, offset, bytes, pnum, map, file);
     if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED || bs == base) {
         return ret;
-- 
2.26.2

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

bdrv_is_allocated_above wrongly handles short backing files: it reports
after-EOF space as UNALLOCATED which is wrong, as on read the data is
generated on the level of short backing file (if all overlays have
unallocated areas at that place).

Reusing bdrv_common_block_status_above fixes the issue and unifies code
path.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20200924194003.22080-5-vsementsov@virtuozzo.com
[Fix s/has/have/ as suggested by Eric Blake. Fix s/area/areas/.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/io.c | 43 +++++--------------------------------------
 1 file changed, 5 insertions(+), 38 deletions(-)

diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
  * at 'offset + *pnum' may return the same allocation status (in other
  * words, the result is not necessarily the maximum possible range);
  * but 'pnum' will only be 0 when end of file is reached.
- *
  */
 int bdrv_is_allocated_above(BlockDriverState *top,
                             BlockDriverState *base,
                             bool include_base, int64_t offset,
                             int64_t bytes, int64_t *pnum)
 {
-    BlockDriverState *intermediate;
-    int ret;
-    int64_t n = bytes;
-
-    assert(base || !include_base);
-
-    intermediate = top;
-    while (include_base || intermediate != base) {
-        int64_t pnum_inter;
-        int64_t size_inter;
-
-        assert(intermediate);
-        ret = bdrv_is_allocated(intermediate, offset, bytes, &pnum_inter);
-        if (ret < 0) {
-            return ret;
-        }
-        if (ret) {
-            *pnum = pnum_inter;
-            return 1;
-        }
-
-        size_inter = bdrv_getlength(intermediate);
-        if (size_inter < 0) {
-            return size_inter;
-        }
-        if (n > pnum_inter &&
-            (intermediate == top || offset + pnum_inter < size_inter)) {
-            n = pnum_inter;
-        }
-
-        if (intermediate == base) {
-            break;
-        }
-
-        intermediate = bdrv_filter_or_cow_bs(intermediate);
+    int ret = bdrv_common_block_status_above(top, base, include_base, false,
+                                             offset, bytes, pnum, NULL, NULL);
+    if (ret < 0) {
+        return ret;
     }
 
-    *pnum = n;
-    return 0;
+    return !!(ret & BDRV_BLOCK_ALLOCATED);
 }
 
 int coroutine_fn
-- 
2.26.2

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

These cases are fixed by previous patches around block_status and
is_allocated.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20200924194003.22080-6-vsementsov@virtuozzo.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/qemu-iotests/274     | 20 +++++++++++
 tests/qemu-iotests/274.out | 68 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+)

diff --git a/tests/qemu-iotests/274 b/tests/qemu-iotests/274
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/274
+++ b/tests/qemu-iotests/274
@@ -XXX,XX +XXX,XX @@ with iotests.FilePath('base') as base, \
     iotests.qemu_io_log('-c', 'read -P 1 0 %d' % size_short, mid)
     iotests.qemu_io_log('-c', 'read -P 0 %d %d' % (size_short, size_diff), mid)
 
+    iotests.log('=== Testing qemu-img commit (top -> base) ===')
+
+    create_chain()
+    iotests.qemu_img_log('commit', '-b', base, top)
+    iotests.img_info_log(base)
+    iotests.qemu_io_log('-c', 'read -P 1 0 %d' % size_short, base)
+    iotests.qemu_io_log('-c', 'read -P 0 %d %d' % (size_short, size_diff), base)
+
+    iotests.log('=== Testing QMP active commit (top -> base) ===')
+
+    create_chain()
+    with create_vm() as vm:
+        vm.launch()
+        vm.qmp_log('block-commit', device='top', base_node='base',
+                   job_id='job0', auto_dismiss=False)
+        vm.run_job('job0', wait=5)
+
+    iotests.img_info_log(mid)
+    iotests.qemu_io_log('-c', 'read -P 1 0 %d' % size_short, base)
+    iotests.qemu_io_log('-c', 'read -P 0 %d %d' % (size_short, size_diff), base)
 
     iotests.log('== Resize tests ==')
 
diff --git a/tests/qemu-iotests/274.out b/tests/qemu-iotests/274.out
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/274.out
+++ b/tests/qemu-iotests/274.out
@@ -XXX,XX +XXX,XX @@ read 1048576/1048576 bytes at offset 0
 read 1048576/1048576 bytes at offset 1048576
 1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
+=== Testing qemu-img commit (top -> base) ===
+Formatting 'TEST_DIR/PID-base', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 lazy_refcounts=off refcount_bits=16
+
+Formatting 'TEST_DIR/PID-mid', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=1048576 backing_file=TEST_DIR/PID-base backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
+
+Formatting 'TEST_DIR/PID-top', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 backing_file=TEST_DIR/PID-mid backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
+
+wrote 2097152/2097152 bytes at offset 0
+2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+Image committed.
+
+image: TEST_IMG
+file format: IMGFMT
+virtual size: 2 MiB (2097152 bytes)
+cluster_size: 65536
+Format specific information:
+    compat: 1.1
+    compression type: zlib
+    lazy refcounts: false
+    refcount bits: 16
+    corrupt: false
+    extended l2: false
+
+read 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+read 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+=== Testing QMP active commit (top -> base) ===
+Formatting 'TEST_DIR/PID-base', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 lazy_refcounts=off refcount_bits=16
+
+Formatting 'TEST_DIR/PID-mid', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=1048576 backing_file=TEST_DIR/PID-base backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
+
+Formatting 'TEST_DIR/PID-top', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 backing_file=TEST_DIR/PID-mid backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
+
+wrote 2097152/2097152 bytes at offset 0
+2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+{"execute": "block-commit", "arguments": {"auto-dismiss": false, "base-node": "base", "device": "top", "job-id": "job0"}}
+{"return": {}}
+{"execute": "job-complete", "arguments": {"id": "job0"}}
+{"return": {}}
+{"data": {"device": "job0", "len": 1048576, "offset": 1048576, "speed": 0, "type": "commit"}, "event": "BLOCK_JOB_READY", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"data": {"device": "job0", "len": 1048576, "offset": 1048576, "speed": 0, "type": "commit"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"execute": "job-dismiss", "arguments": {"id": "job0"}}
+{"return": {}}
+image: TEST_IMG
+file format: IMGFMT
+virtual size: 1 MiB (1048576 bytes)
+cluster_size: 65536
+backing file: TEST_DIR/PID-base
+backing file format: IMGFMT
+Format specific information:
+    compat: 1.1
+    compression type: zlib
+    lazy refcounts: false
+    refcount bits: 16
+    corrupt: false
+    extended l2: false
+
+read 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+read 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
 == Resize tests ==
 === preallocation=off ===
 Formatting 'TEST_DIR/PID-base', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=6442450944 lazy_refcounts=off refcount_bits=16
-- 
2.26.2