Series comparison

The following changes since commit 31ee895047bdcf7387e3570cbd2a473c6f744b08:

Merge remote-tracking branch 'remotes/jasowang/tags/net-pull-request' into staging (2021-01-25 15:56:13 +0000)

are available in the Git repository at:

https://github.com/XanClic/qemu.git tags/pull-block-2021-01-26

for you to fetch changes up to bb24cdc5efee580e81f71c5ff0fd980f2cc179d0:

iotests/178: Pass value to invalid option (2021-01-26 14:36:37 +0100)

----------------------------------------------------------------
Block patches:
- Make backup block jobs use asynchronous requests with the block-copy
  module
- Use COR filter node for stream block jobs
- Make coroutine-sigaltstack’s qemu_coroutine_new() function thread-safe
- Report error string when file locking fails with an unexpected errno
- iotest fixes, additions, and some refactoring

----------------------------------------------------------------
Alberto Garcia (1):
  iotests: Add test for the regression fixed in c8bf9a9169

Andrey Shinkevich (10):
  copy-on-read: support preadv/pwritev_part functions
  block: add API function to insert a node
  copy-on-read: add filter drop function
  qapi: add filter-node-name to block-stream
  qapi: copy-on-read filter: add 'bottom' option
  iotests: add #310 to test bottom node in COR driver
  block: include supported_read_flags into BDS structure
  copy-on-read: skip non-guest reads if no copy needed
  stream: rework backing-file changing
  block: apply COR-filter to block-stream jobs

David Edmondson (1):
  block: report errno when flock fcntl fails

Max Reitz (14):
  iotests.py: Assume a couple of variables as given
  iotests/297: Rewrite in Python and extend reach
  iotests: Move try_remove to iotests.py
  iotests/129: Remove test images in tearDown()
  iotests/129: Do not check @busy
  iotests/129: Use throttle node
  iotests/129: Actually test a commit job
  iotests/129: Limit mirror job's buffer size
  iotests/129: Clean up pylint and mypy complaints
  iotests/300: Clean up pylint and mypy complaints
  coroutine-sigaltstack: Add SIGUSR2 mutex
  iotests/129: Limit backup's max-chunk/max-workers
  iotests/118: Drop 'change' test
  iotests/178: Pass value to invalid option

Vladimir Sementsov-Ogievskiy (27):
  iotests: fix _check_o_direct
  qapi: block-stream: add "bottom" argument
  iotests: 30: prepare to COR filter insertion by stream job
  block/stream: add s->target_bs
  qapi: backup: add perf.use-copy-range parameter
  block/block-copy: More explicit call_state
  block/block-copy: implement block_copy_async
  block/block-copy: add max_chunk and max_workers parameters
  block/block-copy: add list of all call-states
  block/block-copy: add ratelimit to block-copy
  block/block-copy: add block_copy_cancel
  blockjob: add set_speed to BlockJobDriver
  job: call job_enter from job_pause
  qapi: backup: add max-chunk and max-workers to x-perf struct
  iotests: 56: prepare for backup over block-copy
  iotests: 185: prepare for backup over block-copy
  iotests: 219: prepare for backup over block-copy
  iotests: 257: prepare for backup over block-copy
  block/block-copy: make progress_bytes_callback optional
  block/backup: drop extra gotos from backup_run()
  backup: move to block-copy
  qapi: backup: disable copy_range by default
  block/block-copy: drop unused block_copy_set_progress_callback()
  block/block-copy: drop unused argument of block_copy()
  simplebench/bench_block_job: use correct shebang line with python3
  simplebench: bench_block_job: add cmd_options argument
  simplebench: add bench-backup.py

-- 
2.29.2

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

Unfortunately commit "iotests: handle tmpfs" breaks running iotests
with -nbd -nocache, as _check_o_direct tries to create
$TEST_IMG.test_o_direct, but in case of nbd TEST_IMG is something like
nbd+unix:///... , and test fails with message

qemu-img: nbd+unix:///?socket[...]test_o_direct: Protocol driver
    'nbd' does not support image creation, and opening the image
    failed: Failed to connect to '/tmp/tmp.[...]/nbd/test_o_direct': No
    such file or directory

Use TEST_DIR instead.

Fixes: cfdca2b9f9d4ca26bb2b2dfe8de3149092e39170
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201218182012.47607-1-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/qemu-iotests/common.rc | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -XXX,XX +XXX,XX @@ _supported_cache_modes()
 # Check whether the filesystem supports O_DIRECT
 _check_o_direct()
 {
-    $QEMU_IMG create -f raw "$TEST_IMG".test_o_direct 1M > /dev/null
-    out=$($QEMU_IO -f raw -t none -c quit "$TEST_IMG".test_o_direct 2>&1)
-    rm -f "$TEST_IMG".test_o_direct
+    testfile="$TEST_DIR"/_check_o_direct
+    $QEMU_IMG create -f raw "$testfile" 1M > /dev/null
+    out=$($QEMU_IO -f raw -t none -c quit "$testfile" 2>&1)
+    rm -f "$testfile"
 
     [[ "$out" != *"O_DIRECT"* ]]
 }
-- 
2.29.2

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

Add support for the recently introduced functions
bdrv_co_preadv_part()
and
bdrv_co_pwritev_part()
to the COR-filter driver.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201216061703.70908-2-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/copy-on-read.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index XXXXXXX..XXXXXXX 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -XXX,XX +XXX,XX @@ static int64_t cor_getlength(BlockDriverState *bs)
 }
 
 
-static int coroutine_fn cor_co_preadv(BlockDriverState *bs,
-                                      uint64_t offset, uint64_t bytes,
-                                      QEMUIOVector *qiov, int flags)
+static int coroutine_fn cor_co_preadv_part(BlockDriverState *bs,
+                                           uint64_t offset, uint64_t bytes,
+                                           QEMUIOVector *qiov,
+                                           size_t qiov_offset,
+                                           int flags)
 {
-    return bdrv_co_preadv(bs->file, offset, bytes, qiov,
-                          flags | BDRV_REQ_COPY_ON_READ);
+    return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset,
+                               flags | BDRV_REQ_COPY_ON_READ);
 }
 
 
-static int coroutine_fn cor_co_pwritev(BlockDriverState *bs,
-                                       uint64_t offset, uint64_t bytes,
-                                       QEMUIOVector *qiov, int flags)
+static int coroutine_fn cor_co_pwritev_part(BlockDriverState *bs,
+                                            uint64_t offset,
+                                            uint64_t bytes,
+                                            QEMUIOVector *qiov,
+                                            size_t qiov_offset, int flags)
 {
-
-    return bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
+    return bdrv_co_pwritev_part(bs->file, offset, bytes, qiov, qiov_offset,
+                                flags);
 }
 
 
@@ -XXX,XX +XXX,XX @@ static BlockDriver bdrv_copy_on_read = {
 
     .bdrv_getlength                     = cor_getlength,
 
-    .bdrv_co_preadv                     = cor_co_preadv,
-    .bdrv_co_pwritev                    = cor_co_pwritev,
+    .bdrv_co_preadv_part                = cor_co_preadv_part,
+    .bdrv_co_pwritev_part               = cor_co_pwritev_part,
     .bdrv_co_pwrite_zeroes              = cor_co_pwrite_zeroes,
     .bdrv_co_pdiscard                   = cor_co_pdiscard,
     .bdrv_co_pwritev_compressed         = cor_co_pwritev_compressed,
-- 
2.29.2

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

Provide API for insertion a node to backing chain.

Suggested-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20201216061703.70908-3-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block.h |  2 ++
 block.c               | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/include/block/block.h b/include/block/block.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -XXX,XX +XXX,XX @@ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
                  Error **errp);
 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
                        Error **errp);
+BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *node_options,
+                                   int flags, Error **errp);
 
 int bdrv_parse_aio(const char *mode, int *flags);
 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
diff --git a/block.c b/block.c
index XXXXXXX..XXXXXXX 100644
--- a/block.c
+++ b/block.c
@@ -XXX,XX +XXX,XX @@ static void bdrv_delete(BlockDriverState *bs)
     g_free(bs);
 }
 
+BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *node_options,
+                                   int flags, Error **errp)
+{
+    BlockDriverState *new_node_bs;
+    Error *local_err = NULL;
+
+    new_node_bs = bdrv_open(NULL, NULL, node_options, flags, errp);
+    if (new_node_bs == NULL) {
+        error_prepend(errp, "Could not create node: ");
+        return NULL;
+    }
+
+    bdrv_drained_begin(bs);
+    bdrv_replace_node(bs, new_node_bs, &local_err);
+    bdrv_drained_end(bs);
+
+    if (local_err) {
+        bdrv_unref(new_node_bs);
+        error_propagate(errp, local_err);
+        return NULL;
+    }
+
+    return new_node_bs;
+}
+
 /*
  * Run consistency checks on an image
  *
-- 
2.29.2

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

Provide API for the COR-filter removal. Also, drop the filter child
permissions for an inactive state when the filter node is being
removed.
To insert the filter, the block generic layer function
bdrv_insert_node() can be used.
The new function bdrv_cor_filter_drop() may be considered as an
intermediate solution before the QEMU permission update system has
overhauled. Then we are able to implement the API function
bdrv_remove_node() on the block generic layer.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20201216061703.70908-4-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/copy-on-read.h | 32 +++++++++++++++++++++++++
 block/copy-on-read.c | 56 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 block/copy-on-read.h

diff --git a/block/copy-on-read.h b/block/copy-on-read.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/block/copy-on-read.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * Copy-on-read filter block driver
+ *
+ * The filter driver performs Copy-On-Read (COR) operations
+ *
+ * Copyright (c) 2018-2020 Virtuozzo International GmbH.
+ *
+ * Author:
+ *   Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef BLOCK_COPY_ON_READ
+#define BLOCK_COPY_ON_READ
+
+#include "block/block_int.h"
+
+void bdrv_cor_filter_drop(BlockDriverState *cor_filter_bs);
+
+#endif /* BLOCK_COPY_ON_READ */
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index XXXXXXX..XXXXXXX 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu/osdep.h"
 #include "block/block_int.h"
 #include "qemu/module.h"
+#include "qapi/error.h"
+#include "block/copy-on-read.h"
+
+
+typedef struct BDRVStateCOR {
+    bool active;
+} BDRVStateCOR;
 
 
 static int cor_open(BlockDriverState *bs, QDict *options, int flags,
                     Error **errp)
 {
+    BDRVStateCOR *state = bs->opaque;
+
     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
                                BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
                                false, errp);
@@ -XXX,XX +XXX,XX @@ static int cor_open(BlockDriverState *bs, QDict *options, int flags,
         ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
             bs->file->bs->supported_zero_flags);
 
+    state->active = true;
+
+    /*
+     * We don't need to call bdrv_child_refresh_perms() now as the permissions
+     * will be updated later when the filter node gets its parent.
+     */
+
     return 0;
 }
 
@@ -XXX,XX +XXX,XX @@ static void cor_child_perm(BlockDriverState *bs, BdrvChild *c,
                            uint64_t perm, uint64_t shared,
                            uint64_t *nperm, uint64_t *nshared)
 {
+    BDRVStateCOR *s = bs->opaque;
+
+    if (!s->active) {
+        /*
+         * While the filter is being removed
+         */
+        *nperm = 0;
+        *nshared = BLK_PERM_ALL;
+        return;
+    }
+
     *nperm = perm & PERM_PASSTHROUGH;
     *nshared = (shared & PERM_PASSTHROUGH) | PERM_UNCHANGED;
 
@@ -XXX,XX +XXX,XX @@ static void cor_lock_medium(BlockDriverState *bs, bool locked)
 
 static BlockDriver bdrv_copy_on_read = {
     .format_name                        = "copy-on-read",
+    .instance_size                      = sizeof(BDRVStateCOR),
 
     .bdrv_open                          = cor_open,
     .bdrv_child_perm                    = cor_child_perm,
@@ -XXX,XX +XXX,XX @@ static BlockDriver bdrv_copy_on_read = {
     .is_filter                          = true,
 };
 
+
+void bdrv_cor_filter_drop(BlockDriverState *cor_filter_bs)
+{
+    BdrvChild *child;
+    BlockDriverState *bs;
+    BDRVStateCOR *s = cor_filter_bs->opaque;
+
+    child = bdrv_filter_child(cor_filter_bs);
+    if (!child) {
+        return;
+    }
+    bs = child->bs;
+
+    /* Retain the BDS until we complete the graph change. */
+    bdrv_ref(bs);
+    /* Hold a guest back from writing while permissions are being reset. */
+    bdrv_drained_begin(bs);
+    /* Drop permissions before the graph change. */
+    s->active = false;
+    bdrv_child_refresh_perms(cor_filter_bs, child, &error_abort);
+    bdrv_replace_node(cor_filter_bs, bs, &error_abort);
+
+    bdrv_drained_end(bs);
+    bdrv_unref(bs);
+    bdrv_unref(cor_filter_bs);
+}
+
+
 static void bdrv_copy_on_read_init(void)
 {
     bdrv_register(&bdrv_copy_on_read);
-- 
2.29.2

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

Provide the possibility to pass the 'filter-node-name' parameter to the
block-stream job as it is done for the commit block job.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
  [vsementsov: comment indentation, s/Since: 5.2/Since: 6.0/]
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20201216061703.70908-5-vsementsov@virtuozzo.com>
[mreitz: s/commit/stream/]
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 qapi/block-core.json           | 6 ++++++
 include/block/block_int.h      | 7 ++++++-
 block/monitor/block-hmp-cmds.c | 4 ++--
 block/stream.c                 | 4 +++-
 blockdev.c                     | 4 +++-
 5 files changed, 20 insertions(+), 5 deletions(-)

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 @@
 #            'stop' and 'enospc' can only be used if the block device
 #            supports io-status (see BlockInfo).  Since 1.3.
 #
+# @filter-node-name: the node name that should be assigned to the
+#                    filter driver that the stream job inserts into the graph
+#                    above @device. If this option is not given, a node name is
+#                    autogenerated. (Since: 6.0)
+#
 # @auto-finalize: When false, this job will wait in a PENDING state after it has
 #                 finished its work, waiting for @block-job-finalize before
 #                 making any block graph changes.
@@ -XXX,XX +XXX,XX @@
   'data': { '*job-id': 'str', 'device': 'str', '*base': 'str',
             '*base-node': 'str', '*backing-file': 'str', '*speed': 'int',
             '*on-error': 'BlockdevOnError',
+            '*filter-node-name': 'str',
             '*auto-finalize': 'bool', '*auto-dismiss': 'bool' } }
 
 ##
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 @@ int is_windows_drive(const char *filename);
  *                  See @BlockJobCreateFlags
  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
  * @on_error: The action to take upon error.
+ * @filter_node_name: The node name that should be assigned to the filter
+ *                    driver that the stream job inserts into the graph above
+ *                    @bs. NULL means that a node name should be autogenerated.
  * @errp: Error object.
  *
  * Start a streaming operation on @bs.  Clusters that are unallocated
@@ -XXX,XX +XXX,XX @@ int is_windows_drive(const char *filename);
 void stream_start(const char *job_id, BlockDriverState *bs,
                   BlockDriverState *base, const char *backing_file_str,
                   int creation_flags, int64_t speed,
-                  BlockdevOnError on_error, Error **errp);
+                  BlockdevOnError on_error,
+                  const char *filter_node_name,
+                  Error **errp);
 
 /**
  * commit_start:
diff --git a/block/monitor/block-hmp-cmds.c b/block/monitor/block-hmp-cmds.c
index XXXXXXX..XXXXXXX 100644
--- a/block/monitor/block-hmp-cmds.c
+++ b/block/monitor/block-hmp-cmds.c
@@ -XXX,XX +XXX,XX @@ void hmp_block_stream(Monitor *mon, const QDict *qdict)
 
     qmp_block_stream(true, device, device, base != NULL, base, false, NULL,
                      false, NULL, qdict_haskey(qdict, "speed"), speed, true,
-                     BLOCKDEV_ON_ERROR_REPORT, false, false, false, false,
-                     &error);
+                     BLOCKDEV_ON_ERROR_REPORT, false, NULL, false, false, false,
+                     false, &error);
 
     hmp_handle_error(mon, error);
 }
diff --git a/block/stream.c b/block/stream.c
index XXXXXXX..XXXXXXX 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver stream_job_driver = {
 void stream_start(const char *job_id, BlockDriverState *bs,
                   BlockDriverState *base, const char *backing_file_str,
                   int creation_flags, int64_t speed,
-                  BlockdevOnError on_error, Error **errp)
+                  BlockdevOnError on_error,
+                  const char *filter_node_name,
+                  Error **errp)
 {
     StreamBlockJob *s;
     BlockDriverState *iter;
diff --git a/blockdev.c b/blockdev.c
index XXXXXXX..XXXXXXX 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
                       bool has_backing_file, const char *backing_file,
                       bool has_speed, int64_t speed,
                       bool has_on_error, BlockdevOnError on_error,
+                      bool has_filter_node_name, const char *filter_node_name,
                       bool has_auto_finalize, bool auto_finalize,
                       bool has_auto_dismiss, bool auto_dismiss,
                       Error **errp)
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
     }
 
     stream_start(has_job_id ? job_id : NULL, bs, base_bs, base_name,
-                 job_flags, has_speed ? speed : 0, on_error, &local_err);
+                 job_flags, has_speed ? speed : 0, on_error,
+                 filter_node_name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         goto out;
-- 
2.29.2

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

Add an option to limit copy-on-read operations to specified sub-chain
of backing-chain, to make copy-on-read filter useful for block-stream
job.

Suggested-by: Max Reitz <mreitz@redhat.com>
Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
  [vsementsov: change subject, modified to freeze the chain,
   do some fixes]
Message-Id: <20201216061703.70908-6-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 qapi/block-core.json | 20 ++++++++-
 block/copy-on-read.c | 98 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 115 insertions(+), 3 deletions(-)

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 @@
   'data': { 'throttle-group': 'str',
             'file' : 'BlockdevRef'
              } }
+
+##
+# @BlockdevOptionsCor:
+#
+# Driver specific block device options for the copy-on-read driver.
+#
+# @bottom: The name of a non-filter node (allocation-bearing layer) that
+#          limits the COR operations in the backing chain (inclusive), so
+#          that no data below this node will be copied by this filter.
+#          If option is absent, the limit is not applied, so that data
+#          from all backing layers may be copied.
+#
+# Since: 6.0
+##
+{ 'struct': 'BlockdevOptionsCor',
+  'base': 'BlockdevOptionsGenericFormat',
+  'data': { '*bottom': 'str' } }
+
 ##
 # @BlockdevOptions:
 #
@@ -XXX,XX +XXX,XX @@
       'bochs':      'BlockdevOptionsGenericFormat',
       'cloop':      'BlockdevOptionsGenericFormat',
       'compress':   'BlockdevOptionsGenericFormat',
-      'copy-on-read':'BlockdevOptionsGenericFormat',
+      'copy-on-read':'BlockdevOptionsCor',
       'dmg':        'BlockdevOptionsGenericFormat',
       'file':       'BlockdevOptionsFile',
       'ftp':        'BlockdevOptionsCurlFtp',
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index XXXXXXX..XXXXXXX 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -XXX,XX +XXX,XX @@
 #include "block/block_int.h"
 #include "qemu/module.h"
 #include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
 #include "block/copy-on-read.h"
 
 
 typedef struct BDRVStateCOR {
     bool active;
+    BlockDriverState *bottom_bs;
+    bool chain_frozen;
 } BDRVStateCOR;
 
 
 static int cor_open(BlockDriverState *bs, QDict *options, int flags,
                     Error **errp)
 {
+    BlockDriverState *bottom_bs = NULL;
     BDRVStateCOR *state = bs->opaque;
+    /* Find a bottom node name, if any */
+    const char *bottom_node = qdict_get_try_str(options, "bottom");
 
     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
                                BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
@@ -XXX,XX +XXX,XX @@ static int cor_open(BlockDriverState *bs, QDict *options, int flags,
         ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
             bs->file->bs->supported_zero_flags);
 
+    if (bottom_node) {
+        bottom_bs = bdrv_find_node(bottom_node);
+        if (!bottom_bs) {
+            error_setg(errp, "Bottom node '%s' not found", bottom_node);
+            qdict_del(options, "bottom");
+            return -EINVAL;
+        }
+        qdict_del(options, "bottom");
+
+        if (!bottom_bs->drv) {
+            error_setg(errp, "Bottom node '%s' not opened", bottom_node);
+            return -EINVAL;
+        }
+
+        if (bottom_bs->drv->is_filter) {
+            error_setg(errp, "Bottom node '%s' is a filter", bottom_node);
+            return -EINVAL;
+        }
+
+        if (bdrv_freeze_backing_chain(bs, bottom_bs, errp) < 0) {
+            return -EINVAL;
+        }
+        state->chain_frozen = true;
+
+        /*
+         * We do freeze the chain, so it shouldn't be removed. Still, storing a
+         * pointer worth bdrv_ref().
+         */
+        bdrv_ref(bottom_bs);
+    }
     state->active = true;
+    state->bottom_bs = bottom_bs;
 
     /*
      * We don't need to call bdrv_child_refresh_perms() now as the permissions
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn cor_co_preadv_part(BlockDriverState *bs,
                                            size_t qiov_offset,
                                            int flags)
 {
-    return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset,
-                               flags | BDRV_REQ_COPY_ON_READ);
+    int64_t n;
+    int local_flags;
+    int ret;
+    BDRVStateCOR *state = bs->opaque;
+
+    if (!state->bottom_bs) {
+        return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset,
+                                   flags | BDRV_REQ_COPY_ON_READ);
+    }
+
+    while (bytes) {
+        local_flags = flags;
+
+        /* In case of failure, try to copy-on-read anyway */
+        ret = bdrv_is_allocated(bs->file->bs, offset, bytes, &n);
+        if (ret <= 0) {
+            ret = bdrv_is_allocated_above(bdrv_backing_chain_next(bs->file->bs),
+                                          state->bottom_bs, true, offset,
+                                          n, &n);
+            if (ret > 0 || ret < 0) {
+                local_flags |= BDRV_REQ_COPY_ON_READ;
+            }
+            /* Finish earlier if the end of a backing file has been reached */
+            if (n == 0) {
+                break;
+            }
+        }
+
+        ret = bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offset,
+                                  local_flags);
+        if (ret < 0) {
+            return ret;
+        }
+
+        offset += n;
+        qiov_offset += n;
+        bytes -= n;
+    }
+
+    return 0;
 }
 
 
@@ -XXX,XX +XXX,XX @@ static void cor_lock_medium(BlockDriverState *bs, bool locked)
 }
 
 
+static void cor_close(BlockDriverState *bs)
+{
+    BDRVStateCOR *s = bs->opaque;
+
+    if (s->chain_frozen) {
+        s->chain_frozen = false;
+        bdrv_unfreeze_backing_chain(bs, s->bottom_bs);
+    }
+
+    bdrv_unref(s->bottom_bs);
+}
+
+
 static BlockDriver bdrv_copy_on_read = {
     .format_name                        = "copy-on-read",
     .instance_size                      = sizeof(BDRVStateCOR),
 
     .bdrv_open                          = cor_open,
+    .bdrv_close                         = cor_close,
     .bdrv_child_perm                    = cor_child_perm,
 
     .bdrv_getlength                     = cor_getlength,
@@ -XXX,XX +XXX,XX @@ void bdrv_cor_filter_drop(BlockDriverState *cor_filter_bs)
     bdrv_drained_begin(bs);
     /* Drop permissions before the graph change. */
     s->active = false;
+    /* unfreeze, as otherwise bdrv_replace_node() will fail */
+    if (s->chain_frozen) {
+        s->chain_frozen = false;
+        bdrv_unfreeze_backing_chain(cor_filter_bs, s->bottom_bs);
+    }
     bdrv_child_refresh_perms(cor_filter_bs, child, &error_abort);
     bdrv_replace_node(cor_filter_bs, bs, &error_abort);
 
-- 
2.29.2

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

The test case #310 is similar to #216 by Max Reitz. The difference is
that the test #310 involves a bottom node to the COR filter driver.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
  [vsementsov: detach backing to test reads from top, limit to qcow2]
Message-Id: <20201216061703.70908-7-vsementsov@virtuozzo.com>
[mreitz: Add "# group:" line]
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/qemu-iotests/310     | 117 +++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/310.out |  15 +++++
 tests/qemu-iotests/group   |   1 +
 3 files changed, 133 insertions(+)
 create mode 100755 tests/qemu-iotests/310
 create mode 100644 tests/qemu-iotests/310.out

diff --git a/tests/qemu-iotests/310 b/tests/qemu-iotests/310
new file mode 100755
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/tests/qemu-iotests/310
@@ -XXX,XX +XXX,XX @@
+#!/usr/bin/env python3
+# group: rw quick
+#
+# Copy-on-read tests using a COR filter with a bottom node
+#
+# Copyright (C) 2018 Red Hat, Inc.
+# Copyright (c) 2020 Virtuozzo International GmbH
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import iotests
+from iotests import log, qemu_img, qemu_io_silent
+
+# Need backing file support
+iotests.script_initialize(supported_fmts=['qcow2'],
+                          supported_platforms=['linux'])
+
+log('')
+log('=== Copy-on-read across nodes ===')
+log('')
+
+# This test is similar to the 216 one by Max Reitz <mreitz@redhat.com>
+# The difference is that this test case involves a bottom node to the
+# COR filter driver.
+
+with iotests.FilePath('base.img') as base_img_path, \
+     iotests.FilePath('mid.img') as mid_img_path, \
+     iotests.FilePath('top.img') as top_img_path, \
+     iotests.VM() as vm:
+
+    log('--- Setting up images ---')
+    log('')
+
+    assert qemu_img('create', '-f', iotests.imgfmt, base_img_path, '64M') == 0
+    assert qemu_io_silent(base_img_path, '-c', 'write -P 1 0M 1M') == 0
+    assert qemu_io_silent(base_img_path, '-c', 'write -P 1 3M 1M') == 0
+    assert qemu_img('create', '-f', iotests.imgfmt, '-b', base_img_path,
+                    '-F', iotests.imgfmt, mid_img_path) == 0
+    assert qemu_io_silent(mid_img_path,  '-c', 'write -P 3 2M 1M') == 0
+    assert qemu_io_silent(mid_img_path,  '-c', 'write -P 3 4M 1M') == 0
+    assert qemu_img('create', '-f', iotests.imgfmt, '-b', mid_img_path,
+                    '-F', iotests.imgfmt, top_img_path) == 0
+    assert qemu_io_silent(top_img_path,  '-c', 'write -P 2 1M 1M') == 0
+
+#      0 1 2 3 4
+# top    2
+# mid      3   3
+# base 1     1
+
+    log('Done')
+
+    log('')
+    log('--- Doing COR ---')
+    log('')
+
+    vm.launch()
+
+    log(vm.qmp('blockdev-add',
+               node_name='node0',
+               driver='copy-on-read',
+               bottom='node2',
+               file={
+                   'driver': iotests.imgfmt,
+                   'file': {
+                       'driver': 'file',
+                       'filename': top_img_path
+                   },
+                   'backing': {
+                       'node-name': 'node2',
+                       'driver': iotests.imgfmt,
+                       'file': {
+                           'driver': 'file',
+                           'filename': mid_img_path
+                       },
+                       'backing': {
+                           'driver': iotests.imgfmt,
+                           'file': {
+                               'driver': 'file',
+                               'filename': base_img_path
+                           }
+                       },
+                   }
+               }))
+
+    # Trigger COR
+    log(vm.qmp('human-monitor-command',
+               command_line='qemu-io node0 "read 0 5M"'))
+
+    vm.shutdown()
+
+    log('')
+    log('--- Checking COR result ---')
+    log('')
+
+    # Detach backing to check that we can read the data from the top level now
+    assert qemu_img('rebase', '-u', '-b', '', '-f', iotests.imgfmt,
+                    top_img_path) == 0
+
+    assert qemu_io_silent(top_img_path,  '-c', 'read -P 0 0 1M') == 0
+    assert qemu_io_silent(top_img_path,  '-c', 'read -P 2 1M 1M') == 0
+    assert qemu_io_silent(top_img_path,  '-c', 'read -P 3 2M 1M') == 0
+    assert qemu_io_silent(top_img_path,  '-c', 'read -P 0 3M 1M') == 0
+    assert qemu_io_silent(top_img_path,  '-c', 'read -P 3 4M 1M') == 0
+
+    log('Done')
diff --git a/tests/qemu-iotests/310.out b/tests/qemu-iotests/310.out
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/tests/qemu-iotests/310.out
@@ -XXX,XX +XXX,XX @@
+
+=== Copy-on-read across nodes ===
+
+--- Setting up images ---
+
+Done
+
+--- Doing COR ---
+
+{"return": {}}
+{"return": ""}
+
+--- Checking COR result ---
+
+Done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -XXX,XX +XXX,XX @@
 307 rw quick export
 308 rw
 309 rw auto quick
+310 rw quick
 312 rw quick
-- 
2.29.2

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

Add the new member supported_read_flags to the BlockDriverState
structure. It will control the flags set for copy-on-read operations.
Make the block generic layer evaluate supported read flags before they
go to a block driver.

Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
 [vsementsov: use assert instead of abort]
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20201216061703.70908-8-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block_int.h |  4 ++++
 block/io.c                | 10 ++++++++--
 2 files changed, 12 insertions(+), 2 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 BlockDriverState {
     /* I/O Limits */
     BlockLimits bl;
 
+    /*
+     * Flags honored during pread
+     */
+    unsigned int supported_read_flags;
     /* Flags honored during pwrite (so far: BDRV_REQ_FUA,
      * BDRV_REQ_WRITE_UNCHANGED).
      * If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those
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_preadv(BdrvChild *child,
     if (flags & BDRV_REQ_COPY_ON_READ) {
         int64_t pnum;
 
+        /* The flag BDRV_REQ_COPY_ON_READ has reached its addressee */
+        flags &= ~BDRV_REQ_COPY_ON_READ;
+
         ret = bdrv_is_allocated(bs, offset, bytes, &pnum);
         if (ret < 0) {
             goto out;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
         goto out;
     }
 
+    assert(!(flags & ~bs->supported_read_flags));
+
     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, qiov_offset, 0);
+        ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, flags);
         goto out;
     }
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
 
             ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining,
                                      num, qiov,
-                                     qiov_offset + bytes - bytes_remaining, 0);
+                                     qiov_offset + bytes - bytes_remaining,
+                                     flags);
             max_bytes -= num;
         } else {
             num = bytes_remaining;
-- 
2.29.2

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

If the flag BDRV_REQ_PREFETCH was set, skip idling read/write
operations in COR-driver. It can be taken into account for the
COR-algorithms optimization. That check is being made during the
block stream job by the moment.

Add the BDRV_REQ_PREFETCH flag to the supported_read_flags of the
COR-filter.

block: Modify the comment for the flag BDRV_REQ_PREFETCH as we are
going to use it alone and pass it to the COR-filter driver for further
processing.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20201216061703.70908-9-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block.h |  8 +++++---
 block/copy-on-read.c  | 14 ++++++++++----
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/include/block/block.h b/include/block/block.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -XXX,XX +XXX,XX @@ typedef enum {
     BDRV_REQ_NO_FALLBACK        = 0x100,
 
     /*
-     * BDRV_REQ_PREFETCH may be used only together with BDRV_REQ_COPY_ON_READ
-     * on read request and means that caller doesn't really need data to be
-     * written to qiov parameter which may be NULL.
+     * BDRV_REQ_PREFETCH makes sense only in the context of copy-on-read
+     * (i.e., together with the BDRV_REQ_COPY_ON_READ flag or when a COR
+     * filter is involved), in which case it signals that the COR operation
+     * need not read the data into memory (qiov) but only ensure they are
+     * copied to the top layer (i.e., that COR operation is done).
      */
     BDRV_REQ_PREFETCH  = 0x200,
 
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index XXXXXXX..XXXXXXX 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -XXX,XX +XXX,XX @@ static int cor_open(BlockDriverState *bs, QDict *options, int flags,
         return -EINVAL;
     }
 
+    bs->supported_read_flags = BDRV_REQ_PREFETCH;
+
     bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
         (BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn cor_co_preadv_part(BlockDriverState *bs,
             }
         }
 
-        ret = bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offset,
-                                  local_flags);
-        if (ret < 0) {
-            return ret;
+        /* Skip if neither read nor write are needed */
+        if ((local_flags & (BDRV_REQ_PREFETCH | BDRV_REQ_COPY_ON_READ)) !=
+            BDRV_REQ_PREFETCH) {
+            ret = bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offset,
+                                      local_flags);
+            if (ret < 0) {
+                return ret;
+            }
         }
 
         offset += n;
-- 
2.29.2

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

Stream in stream_prepare calls bdrv_change_backing_file() to change
backing-file in the metadata of bs.

It may use either backing-file parameter given by user or just take
filename of base on job start.

Backing file format is determined by base on job finish.

There are some problems with this design, we solve only two by this
patch:

1. Consider scenario with backing-file unset. Current concept of stream
supports changing of the base during the job (we don't freeze link to
the base). So, we should not save base filename at job start,

- let's determine name of the base on job finish.

2. Using direct base to determine filename and format is not very good:
base node may be a filter, so its filename may be JSON, and format_name
is not good for storing into qcow2 metadata as backing file format.

- let's use unfiltered_base

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
  [vsementsov: change commit subject, change logic in stream_prepare]
Message-Id: <20201216061703.70908-10-vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/stream.c | 9 +++++----
 blockdev.c     | 8 +-------
 2 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/block/stream.c b/block/stream.c
index XXXXXXX..XXXXXXX 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -XXX,XX +XXX,XX @@ static int stream_prepare(Job *job)
     BlockDriverState *bs = blk_bs(bjob->blk);
     BlockDriverState *unfiltered_bs = bdrv_skip_filters(bs);
     BlockDriverState *base = bdrv_filter_or_cow_bs(s->above_base);
+    BlockDriverState *unfiltered_base = bdrv_skip_filters(base);
     Error *local_err = NULL;
     int ret = 0;
 
@@ -XXX,XX +XXX,XX @@ static int stream_prepare(Job *job)
 
     if (bdrv_cow_child(unfiltered_bs)) {
         const char *base_id = NULL, *base_fmt = NULL;
-        if (base) {
-            base_id = s->backing_file_str;
-            if (base->drv) {
-                base_fmt = base->drv->format_name;
+        if (unfiltered_base) {
+            base_id = s->backing_file_str ?: unfiltered_base->filename;
+            if (unfiltered_base->drv) {
+                base_fmt = unfiltered_base->drv->format_name;
             }
         }
         bdrv_set_backing_hd(unfiltered_bs, base, &local_err);
diff --git a/blockdev.c b/blockdev.c
index XXXXXXX..XXXXXXX 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
     BlockDriverState *base_bs = NULL;
     AioContext *aio_context;
     Error *local_err = NULL;
-    const char *base_name = NULL;
     int job_flags = JOB_DEFAULT;
 
     if (!has_on_error) {
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
             goto out;
         }
         assert(bdrv_get_aio_context(base_bs) == aio_context);
-        base_name = base;
     }
 
     if (has_base_node) {
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
         }
         assert(bdrv_get_aio_context(base_bs) == aio_context);
         bdrv_refresh_filename(base_bs);
-        base_name = base_bs->filename;
     }
 
     /* Check for op blockers in the whole chain between bs and base */
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
         goto out;
     }
 
-    /* backing_file string overrides base bs filename */
-    base_name = has_backing_file ? backing_file : base_name;
-
     if (has_auto_finalize && !auto_finalize) {
         job_flags |= JOB_MANUAL_FINALIZE;
     }
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
         job_flags |= JOB_MANUAL_DISMISS;
     }
 
-    stream_start(has_job_id ? job_id : NULL, bs, base_bs, base_name,
+    stream_start(has_job_id ? job_id : NULL, bs, base_bs, backing_file,
                  job_flags, has_speed ? speed : 0, on_error,
                  filter_node_name, &local_err);
     if (local_err) {
-- 
2.29.2

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

The code already don't freeze base node and we try to make it prepared
for the situation when base node is changed during the operation. In
other words, block-stream doesn't own base node.

Let's introduce a new interface which should replace the current one,
which will in better relations with the code. Specifying bottom node
instead of base, and requiring it to be non-filter gives us the
following benefits:

- drop difference between above_base and base_overlay, which will be
   renamed to just bottom, when old interface dropped

- clean way to work with parallel streams/commits on the same backing
   chain, which otherwise become a problem when we introduce a filter
   for stream job

- cleaner interface. Nobody will surprised the fact that base node may
   disappear during block-stream, when there is no word about "base" in
   the interface.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201216061703.70908-11-vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 qapi/block-core.json           | 12 ++++---
 include/block/block_int.h      |  1 +
 block/monitor/block-hmp-cmds.c |  3 +-
 block/stream.c                 | 50 +++++++++++++++++++---------
 blockdev.c                     | 59 ++++++++++++++++++++++++++++------
 5 files changed, 94 insertions(+), 31 deletions(-)

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 @@
 # @device: the device or node name of the top image
 #
 # @base: the common backing file name.
-#        It cannot be set if @base-node is also set.
+#        It cannot be set if @base-node or @bottom is also set.
 #
 # @base-node: the node name of the backing file.
-#             It cannot be set if @base is also set. (Since 2.8)
+#             It cannot be set if @base or @bottom is also set. (Since 2.8)
+#
+# @bottom: the last node in the chain that should be streamed into
+#          top. It cannot be set if @base or @base-node is also set.
+#          It cannot be filter node. (Since 6.0)
 #
 # @backing-file: The backing file string to write into the top
 #                image. This filename is not validated.
@@ -XXX,XX +XXX,XX @@
 ##
 { 'command': 'block-stream',
   'data': { '*job-id': 'str', 'device': 'str', '*base': 'str',
-            '*base-node': 'str', '*backing-file': 'str', '*speed': 'int',
-            '*on-error': 'BlockdevOnError',
+            '*base-node': 'str', '*backing-file': 'str', '*bottom': 'str',
+            '*speed': 'int', '*on-error': 'BlockdevOnError',
             '*filter-node-name': 'str',
             '*auto-finalize': 'bool', '*auto-dismiss': 'bool' } }
 
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 @@ int is_windows_drive(const char *filename);
  */
 void stream_start(const char *job_id, BlockDriverState *bs,
                   BlockDriverState *base, const char *backing_file_str,
+                  BlockDriverState *bottom,
                   int creation_flags, int64_t speed,
                   BlockdevOnError on_error,
                   const char *filter_node_name,
diff --git a/block/monitor/block-hmp-cmds.c b/block/monitor/block-hmp-cmds.c
index XXXXXXX..XXXXXXX 100644
--- a/block/monitor/block-hmp-cmds.c
+++ b/block/monitor/block-hmp-cmds.c
@@ -XXX,XX +XXX,XX @@ void hmp_block_stream(Monitor *mon, const QDict *qdict)
     int64_t speed = qdict_get_try_int(qdict, "speed", 0);
 
     qmp_block_stream(true, device, device, base != NULL, base, false, NULL,
-                     false, NULL, qdict_haskey(qdict, "speed"), speed, true,
+                     false, NULL, false, NULL,
+                     qdict_haskey(qdict, "speed"), speed, true,
                      BLOCKDEV_ON_ERROR_REPORT, false, NULL, false, false, false,
                      false, &error);
 
diff --git a/block/stream.c b/block/stream.c
index XXXXXXX..XXXXXXX 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver stream_job_driver = {
 
 void stream_start(const char *job_id, BlockDriverState *bs,
                   BlockDriverState *base, const char *backing_file_str,
+                  BlockDriverState *bottom,
                   int creation_flags, int64_t speed,
                   BlockdevOnError on_error,
                   const char *filter_node_name,
@@ -XXX,XX +XXX,XX @@ void stream_start(const char *job_id, BlockDriverState *bs,
     BlockDriverState *iter;
     bool bs_read_only;
     int basic_flags = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED;
-    BlockDriverState *base_overlay = bdrv_find_overlay(bs, base);
+    BlockDriverState *base_overlay;
     BlockDriverState *above_base;
 
-    if (!base_overlay) {
-        error_setg(errp, "'%s' is not in the backing chain of '%s'",
-                   base->node_name, bs->node_name);
-        return;
-    }
+    assert(!(base && bottom));
+    assert(!(backing_file_str && bottom));
+
+    if (bottom) {
+        /*
+         * New simple interface. The code is written in terms of old interface
+         * with @base parameter (still, it doesn't freeze link to base, so in
+         * this mean old code is correct for new interface). So, for now, just
+         * emulate base_overlay and above_base. Still, when old interface
+         * finally removed, we should refactor code to use only "bottom", but
+         * not "*base*" things.
+         */
+        assert(!bottom->drv->is_filter);
+        base_overlay = above_base = bottom;
+    } else {
+        base_overlay = bdrv_find_overlay(bs, base);
+        if (!base_overlay) {
+            error_setg(errp, "'%s' is not in the backing chain of '%s'",
+                       base->node_name, bs->node_name);
+            return;
+        }
 
-    /*
-     * Find the node directly above @base.  @base_overlay is a COW overlay, so
-     * it must have a bdrv_cow_child(), but it is the immediate overlay of
-     * @base, so between the two there can only be filters.
-     */
-    above_base = base_overlay;
-    if (bdrv_cow_bs(above_base) != base) {
-        above_base = bdrv_cow_bs(above_base);
-        while (bdrv_filter_bs(above_base) != base) {
-            above_base = bdrv_filter_bs(above_base);
+        /*
+         * Find the node directly above @base.  @base_overlay is a COW overlay,
+         * so it must have a bdrv_cow_child(), but it is the immediate overlay
+         * of @base, so between the two there can only be filters.
+         */
+        above_base = base_overlay;
+        if (bdrv_cow_bs(above_base) != base) {
+            above_base = bdrv_cow_bs(above_base);
+            while (bdrv_filter_bs(above_base) != base) {
+                above_base = bdrv_filter_bs(above_base);
+            }
         }
     }
 
diff --git a/blockdev.c b/blockdev.c
index XXXXXXX..XXXXXXX 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
                       bool has_base, const char *base,
                       bool has_base_node, const char *base_node,
                       bool has_backing_file, const char *backing_file,
+                      bool has_bottom, const char *bottom,
                       bool has_speed, int64_t speed,
                       bool has_on_error, BlockdevOnError on_error,
                       bool has_filter_node_name, const char *filter_node_name,
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
                       bool has_auto_dismiss, bool auto_dismiss,
                       Error **errp)
 {
-    BlockDriverState *bs, *iter;
+    BlockDriverState *bs, *iter, *iter_end;
     BlockDriverState *base_bs = NULL;
+    BlockDriverState *bottom_bs = NULL;
     AioContext *aio_context;
     Error *local_err = NULL;
     int job_flags = JOB_DEFAULT;
 
+    if (has_base && has_base_node) {
+        error_setg(errp, "'base' and 'base-node' cannot be specified "
+                   "at the same time");
+        return;
+    }
+
+    if (has_base && has_bottom) {
+        error_setg(errp, "'base' and 'bottom' cannot be specified "
+                   "at the same time");
+        return;
+    }
+
+    if (has_bottom && has_base_node) {
+        error_setg(errp, "'bottom' and 'base-node' cannot be specified "
+                   "at the same time");
+        return;
+    }
+
     if (!has_on_error) {
         on_error = BLOCKDEV_ON_ERROR_REPORT;
     }
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-    if (has_base && has_base_node) {
-        error_setg(errp, "'base' and 'base-node' cannot be specified "
-                   "at the same time");
-        goto out;
-    }
-
     if (has_base) {
         base_bs = bdrv_find_backing_image(bs, base);
         if (base_bs == NULL) {
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
         bdrv_refresh_filename(base_bs);
     }
 
-    /* Check for op blockers in the whole chain between bs and base */
-    for (iter = bs; iter && iter != base_bs;
+    if (has_bottom) {
+        bottom_bs = bdrv_lookup_bs(NULL, bottom, errp);
+        if (!bottom_bs) {
+            goto out;
+        }
+        if (!bottom_bs->drv) {
+            error_setg(errp, "Node '%s' is not open", bottom);
+            goto out;
+        }
+        if (bottom_bs->drv->is_filter) {
+            error_setg(errp, "Node '%s' is a filter, use a non-filter node "
+                       "as 'bottom'", bottom);
+            goto out;
+        }
+        if (!bdrv_chain_contains(bs, bottom_bs)) {
+            error_setg(errp, "Node '%s' is not in a chain starting from '%s'",
+                       bottom, device);
+            goto out;
+        }
+        assert(bdrv_get_aio_context(bottom_bs) == aio_context);
+    }
+
+    /*
+     * Check for op blockers in the whole chain between bs and base (or bottom)
+     */
+    iter_end = has_bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs;
+    for (iter = bs; iter && iter != iter_end;
          iter = bdrv_filter_or_cow_bs(iter))
     {
         if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_STREAM, errp)) {
@@ -XXX,XX +XXX,XX @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
     }
 
     stream_start(has_job_id ? job_id : NULL, bs, base_bs, backing_file,
-                 job_flags, has_speed ? speed : 0, on_error,
+                 bottom_bs, job_flags, has_speed ? speed : 0, on_error,
                  filter_node_name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-- 
2.29.2

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

test_stream_parallel run parallel stream jobs, intersecting so that top
of one is base of another. It's OK now, but it would be a problem if
insert the filter, as one job will want to use another job's filter as
above_base node.

Correct thing to do is move to new interface: "bottom" argument instead
of base. This guarantees that jobs don't intersect by their actions.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20201216061703.70908-12-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/qemu-iotests/030 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/030 b/tests/qemu-iotests/030
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/030
+++ b/tests/qemu-iotests/030
@@ -XXX,XX +XXX,XX @@ class TestParallelOps(iotests.QMPTestCase):
             node_name = 'node%d' % i
             job_id = 'stream-%s' % node_name
             pending_jobs.append(job_id)
-            result = self.vm.qmp('block-stream', device=node_name, job_id=job_id, base=self.imgs[i-2], speed=1024)
+            result = self.vm.qmp('block-stream', device=node_name,
+                                 job_id=job_id, bottom=f'node{i-1}',
+                                 speed=1024)
             self.assert_qmp(result, 'return', {})
 
         for job in pending_jobs:
-- 
2.29.2

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

Add a direct link to target bs for convenience and to simplify
following commit which will insert COR filter above target bs.

This is a part of original commit written by Andrey.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20201216061703.70908-13-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/stream.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/block/stream.c b/block/stream.c
index XXXXXXX..XXXXXXX 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -XXX,XX +XXX,XX @@ typedef struct StreamBlockJob {
     BlockJob common;
     BlockDriverState *base_overlay; /* COW overlay (stream from this) */
     BlockDriverState *above_base;   /* Node directly above the base */
+    BlockDriverState *target_bs;
     BlockdevOnError on_error;
     char *backing_file_str;
     bool bs_read_only;
@@ -XXX,XX +XXX,XX @@ static void stream_abort(Job *job)
     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
 
     if (s->chain_frozen) {
-        BlockJob *bjob = &s->common;
-        bdrv_unfreeze_backing_chain(blk_bs(bjob->blk), s->above_base);
+        bdrv_unfreeze_backing_chain(s->target_bs, s->above_base);
     }
 }
 
 static int stream_prepare(Job *job)
 {
     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
-    BlockJob *bjob = &s->common;
-    BlockDriverState *bs = blk_bs(bjob->blk);
-    BlockDriverState *unfiltered_bs = bdrv_skip_filters(bs);
+    BlockDriverState *unfiltered_bs = bdrv_skip_filters(s->target_bs);
     BlockDriverState *base = bdrv_filter_or_cow_bs(s->above_base);
     BlockDriverState *unfiltered_base = bdrv_skip_filters(base);
     Error *local_err = NULL;
     int ret = 0;
 
-    bdrv_unfreeze_backing_chain(bs, s->above_base);
+    bdrv_unfreeze_backing_chain(s->target_bs, s->above_base);
     s->chain_frozen = false;
 
     if (bdrv_cow_child(unfiltered_bs)) {
@@ -XXX,XX +XXX,XX @@ static void stream_clean(Job *job)
 {
     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
     BlockJob *bjob = &s->common;
-    BlockDriverState *bs = blk_bs(bjob->blk);
 
     /* Reopen the image back in read-only mode if necessary */
     if (s->bs_read_only) {
         /* Give up write permissions before making it read-only */
         blk_set_perm(bjob->blk, 0, BLK_PERM_ALL, &error_abort);
-        bdrv_reopen_set_read_only(bs, true, NULL);
+        bdrv_reopen_set_read_only(s->target_bs, true, NULL);
     }
 
     g_free(s->backing_file_str);
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_run(Job *job, Error **errp)
 {
     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
     BlockBackend *blk = s->common.blk;
-    BlockDriverState *bs = blk_bs(blk);
-    BlockDriverState *unfiltered_bs = bdrv_skip_filters(bs);
+    BlockDriverState *unfiltered_bs = bdrv_skip_filters(s->target_bs);
     bool enable_cor = !bdrv_cow_child(s->base_overlay);
     int64_t len;
     int64_t offset = 0;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_run(Job *job, Error **errp)
         return 0;
     }
 
-    len = bdrv_getlength(bs);
+    len = bdrv_getlength(s->target_bs);
     if (len < 0) {
         return len;
     }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_run(Job *job, Error **errp)
      * account.
      */
     if (enable_cor) {
-        bdrv_enable_copy_on_read(bs);
+        bdrv_enable_copy_on_read(s->target_bs);
     }
 
     for ( ; offset < len; offset += n) {
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_run(Job *job, Error **errp)
     }
 
     if (enable_cor) {
-        bdrv_disable_copy_on_read(bs);
+        bdrv_disable_copy_on_read(s->target_bs);
     }
 
     /* Do not remove the backing file if an error was there but ignored. */
@@ -XXX,XX +XXX,XX @@ void stream_start(const char *job_id, BlockDriverState *bs,
     s->base_overlay = base_overlay;
     s->above_base = above_base;
     s->backing_file_str = g_strdup(backing_file_str);
+    s->target_bs = bs;
     s->bs_read_only = bs_read_only;
     s->chain_frozen = true;
 
-- 
2.29.2

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

This patch completes the series with the COR-filter applied to
block-stream operations.

Adding the filter makes it possible in future implement discarding
copied regions in backing files during the block-stream job, to reduce
the disk overuse (we need control on permissions).

Also, the filter now is smart enough to do copy-on-read with specified
base, so we have benefit on guest reads even when doing block-stream of
the part of the backing chain.

Several iotests are slightly modified due to filter insertion.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201216061703.70908-14-vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/stream.c             | 105 ++++++++++++++++++++++---------------
 tests/qemu-iotests/030     |   8 +--
 tests/qemu-iotests/141.out |   2 +-
 tests/qemu-iotests/245     |  20 ++++---
 4 files changed, 80 insertions(+), 55 deletions(-)

diff --git a/block/stream.c b/block/stream.c
index XXXXXXX..XXXXXXX 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -XXX,XX +XXX,XX @@
 #include "block/blockjob_int.h"
 #include "qapi/error.h"
 #include "qapi/qmp/qerror.h"
+#include "qapi/qmp/qdict.h"
 #include "qemu/ratelimit.h"
 #include "sysemu/block-backend.h"
+#include "block/copy-on-read.h"
 
 enum {
     /*
@@ -XXX,XX +XXX,XX @@ typedef struct StreamBlockJob {
     BlockJob common;
     BlockDriverState *base_overlay; /* COW overlay (stream from this) */
     BlockDriverState *above_base;   /* Node directly above the base */
+    BlockDriverState *cor_filter_bs;
     BlockDriverState *target_bs;
     BlockdevOnError on_error;
     char *backing_file_str;
     bool bs_read_only;
-    bool chain_frozen;
 } StreamBlockJob;
 
 static int coroutine_fn stream_populate(BlockBackend *blk,
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_populate(BlockBackend *blk,
 {
     assert(bytes < SIZE_MAX);
 
-    return blk_co_preadv(blk, offset, bytes, NULL,
-                         BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH);
-}
-
-static void stream_abort(Job *job)
-{
-    StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
-
-    if (s->chain_frozen) {
-        bdrv_unfreeze_backing_chain(s->target_bs, s->above_base);
-    }
+    return blk_co_preadv(blk, offset, bytes, NULL, BDRV_REQ_PREFETCH);
 }
 
 static int stream_prepare(Job *job)
@@ -XXX,XX +XXX,XX @@ static int stream_prepare(Job *job)
     Error *local_err = NULL;
     int ret = 0;
 
-    bdrv_unfreeze_backing_chain(s->target_bs, s->above_base);
-    s->chain_frozen = false;
+    /* We should drop filter at this point, as filter hold the backing chain */
+    bdrv_cor_filter_drop(s->cor_filter_bs);
+    s->cor_filter_bs = NULL;
 
     if (bdrv_cow_child(unfiltered_bs)) {
         const char *base_id = NULL, *base_fmt = NULL;
@@ -XXX,XX +XXX,XX @@ static void stream_clean(Job *job)
     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
     BlockJob *bjob = &s->common;
 
+    if (s->cor_filter_bs) {
+        bdrv_cor_filter_drop(s->cor_filter_bs);
+        s->cor_filter_bs = NULL;
+    }
+
     /* Reopen the image back in read-only mode if necessary */
     if (s->bs_read_only) {
         /* Give up write permissions before making it read-only */
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_run(Job *job, Error **errp)
     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
     BlockBackend *blk = s->common.blk;
     BlockDriverState *unfiltered_bs = bdrv_skip_filters(s->target_bs);
-    bool enable_cor = !bdrv_cow_child(s->base_overlay);
     int64_t len;
     int64_t offset = 0;
     uint64_t delay_ns = 0;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_run(Job *job, Error **errp)
     }
     job_progress_set_remaining(&s->common.job, len);
 
-    /* Turn on copy-on-read for the whole block device so that guest read
-     * requests help us make progress.  Only do this when copying the entire
-     * backing chain since the copy-on-read operation does not take base into
-     * account.
-     */
-    if (enable_cor) {
-        bdrv_enable_copy_on_read(s->target_bs);
-    }
-
     for ( ; offset < len; offset += n) {
         bool copy;
         int ret;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_run(Job *job, Error **errp)
         }
     }
 
-    if (enable_cor) {
-        bdrv_disable_copy_on_read(s->target_bs);
-    }
-
     /* Do not remove the backing file if an error was there but ignored. */
     return error;
 }
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver stream_job_driver = {
         .free          = block_job_free,
         .run           = stream_run,
         .prepare       = stream_prepare,
-        .abort         = stream_abort,
         .clean         = stream_clean,
         .user_resume   = block_job_user_resume,
     },
@@ -XXX,XX +XXX,XX @@ void stream_start(const char *job_id, BlockDriverState *bs,
     bool bs_read_only;
     int basic_flags = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED;
     BlockDriverState *base_overlay;
+    BlockDriverState *cor_filter_bs = NULL;
     BlockDriverState *above_base;
+    QDict *opts;
 
     assert(!(base && bottom));
     assert(!(backing_file_str && bottom));
@@ -XXX,XX +XXX,XX @@ void stream_start(const char *job_id, BlockDriverState *bs,
         }
     }
 
-    if (bdrv_freeze_backing_chain(bs, above_base, errp) < 0) {
-        return;
-    }
-
     /* Make sure that the image is opened in read-write mode */
     bs_read_only = bdrv_is_read_only(bs);
     if (bs_read_only) {
-        if (bdrv_reopen_set_read_only(bs, false, errp) != 0) {
-            bs_read_only = false;
-            goto fail;
+        int ret;
+        /* Hold the chain during reopen */
+        if (bdrv_freeze_backing_chain(bs, above_base, errp) < 0) {
+            return;
+        }
+
+        ret = bdrv_reopen_set_read_only(bs, false, errp);
+
+        /* failure, or cor-filter will hold the chain */
+        bdrv_unfreeze_backing_chain(bs, above_base);
+
+        if (ret < 0) {
+            return;
         }
     }
 
-    /* Prevent concurrent jobs trying to modify the graph structure here, we
-     * already have our own plans. Also don't allow resize as the image size is
-     * queried only at the job start and then cached. */
-    s = block_job_create(job_id, &stream_job_driver, NULL, bs,
-                         basic_flags | BLK_PERM_GRAPH_MOD,
+    opts = qdict_new();
+
+    qdict_put_str(opts, "driver", "copy-on-read");
+    qdict_put_str(opts, "file", bdrv_get_node_name(bs));
+    /* Pass the base_overlay node name as 'bottom' to COR driver */
+    qdict_put_str(opts, "bottom", base_overlay->node_name);
+    if (filter_node_name) {
+        qdict_put_str(opts, "node-name", filter_node_name);
+    }
+
+    cor_filter_bs = bdrv_insert_node(bs, opts, BDRV_O_RDWR, errp);
+    if (!cor_filter_bs) {
+        goto fail;
+    }
+
+    if (!filter_node_name) {
+        cor_filter_bs->implicit = true;
+    }
+
+    s = block_job_create(job_id, &stream_job_driver, NULL, cor_filter_bs,
+                         BLK_PERM_CONSISTENT_READ,
                          basic_flags | BLK_PERM_WRITE,
                          speed, creation_flags, NULL, NULL, errp);
     if (!s) {
         goto fail;
     }
 
+    /*
+     * Prevent concurrent jobs trying to modify the graph structure here, we
+     * already have our own plans. Also don't allow resize as the image size is
+     * queried only at the job start and then cached.
+     */
+    if (block_job_add_bdrv(&s->common, "active node", bs, 0,
+                           basic_flags | BLK_PERM_WRITE, &error_abort)) {
+        goto fail;
+    }
+
     /* Block all intermediate nodes between bs and base, because they will
      * disappear from the chain after this operation. The streaming job reads
      * every block only once, assuming that it doesn't change, so forbid writes
@@ -XXX,XX +XXX,XX @@ void stream_start(const char *job_id, BlockDriverState *bs,
     s->base_overlay = base_overlay;
     s->above_base = above_base;
     s->backing_file_str = g_strdup(backing_file_str);
+    s->cor_filter_bs = cor_filter_bs;
     s->target_bs = bs;
     s->bs_read_only = bs_read_only;
-    s->chain_frozen = true;
 
     s->on_error = on_error;
     trace_stream_start(bs, base, s);
@@ -XXX,XX +XXX,XX @@ void stream_start(const char *job_id, BlockDriverState *bs,
     return;
 
 fail:
+    if (cor_filter_bs) {
+        bdrv_cor_filter_drop(cor_filter_bs);
+    }
     if (bs_read_only) {
         bdrv_reopen_set_read_only(bs, true, NULL);
     }
-    bdrv_unfreeze_backing_chain(bs, above_base);
 }
diff --git a/tests/qemu-iotests/030 b/tests/qemu-iotests/030
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/030
+++ b/tests/qemu-iotests/030
@@ -XXX,XX +XXX,XX @@ class TestParallelOps(iotests.QMPTestCase):
         self.assert_no_active_block_jobs()
 
         # Set a speed limit to make sure that this job blocks the rest
-        result = self.vm.qmp('block-stream', device='node4', job_id='stream-node4', base=self.imgs[1], speed=1024*1024)
+        result = self.vm.qmp('block-stream', device='node4',
+                             job_id='stream-node4', base=self.imgs[1],
+                             filter_node_name='stream-filter', speed=1024*1024)
         self.assert_qmp(result, 'return', {})
 
         result = self.vm.qmp('block-stream', device='node5', job_id='stream-node5', base=self.imgs[2])
         self.assert_qmp(result, 'error/desc',
-            "Node 'node4' is busy: block device is in use by block job: stream")
+            "Node 'stream-filter' is busy: block device is in use by block job: stream")
 
         result = self.vm.qmp('block-stream', device='node3', job_id='stream-node3', base=self.imgs[2])
         self.assert_qmp(result, 'error/desc',
@@ -XXX,XX +XXX,XX @@ class TestParallelOps(iotests.QMPTestCase):
         # block-commit should also fail if it touches nodes used by the stream job
         result = self.vm.qmp('block-commit', device='drive0', base=self.imgs[4], job_id='commit-node4')
         self.assert_qmp(result, 'error/desc',
-            "Node 'node4' is busy: block device is in use by block job: stream")
+            "Node 'stream-filter' is busy: block device is in use by block job: stream")
 
         result = self.vm.qmp('block-commit', device='drive0', base=self.imgs[1], top=self.imgs[3], job_id='commit-node1')
         self.assert_qmp(result, 'error/desc',
diff --git a/tests/qemu-iotests/141.out b/tests/qemu-iotests/141.out
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/141.out
+++ b/tests/qemu-iotests/141.out
@@ -XXX,XX +XXX,XX @@ wrote 1048576/1048576 bytes at offset 0
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "job0"}}
 {'execute': 'blockdev-del',
           'arguments': {'node-name': 'drv0'}}
-{"error": {"class": "GenericError", "desc": "Node drv0 is in use"}}
+{"error": {"class": "GenericError", "desc": "Node 'drv0' is busy: block device is in use by block job: stream"}}
 {'execute': 'block-job-cancel',
           'arguments': {'device': 'job0'}}
 {"return": {}}
diff --git a/tests/qemu-iotests/245 b/tests/qemu-iotests/245
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/245
+++ b/tests/qemu-iotests/245
@@ -XXX,XX +XXX,XX @@ class TestBlockdevReopen(iotests.QMPTestCase):
 
         # hd1 <- hd0
         result = self.vm.qmp('block-stream', conv_keys = True, job_id = 'stream0',
-                             device = 'hd1', auto_finalize = False)
+                             device = 'hd1', filter_node_name='cor',
+                             auto_finalize = False)
         self.assert_qmp(result, 'return', {})
 
-        # We can't reopen with the original options because that would
-        # make hd1 read-only and block-stream requires it to be read-write
-        # (Which error message appears depends on whether the stream job is
-        # already done with copying at this point.)
+        # We can't reopen with the original options because there is a filter
+        # inserted by stream job above hd1.
         self.reopen(opts, {},
-            ["Can't set node 'hd1' to r/o with copy-on-read enabled",
-             "Cannot make block node read-only, there is a writer on it"])
+                    "Cannot change the option 'backing.backing.file.node-name'")
+
+        # We can't reopen hd1 to read-only, as block-stream requires it to be
+        # read-write
+        self.reopen(opts['backing'], {'read-only': True},
+                    "Cannot make block node read-only, there is a writer on it")
 
         # We can't remove hd2 while the stream job is ongoing
         opts['backing']['backing'] = None
-        self.reopen(opts, {'backing.read-only': False}, "Cannot change 'backing' link from 'hd1' to 'hd2'")
+        self.reopen(opts['backing'], {'read-only': False},
+                    "Cannot change 'backing' link from 'hd1' to 'hd2'")
 
         # We can detach hd1 from hd0 because it doesn't affect the stream job
         opts['backing'] = None
-- 
2.29.2

There are a couple of environment variables that we fetch with
os.environ.get() without supplying a default.  Clearly they are required
and expected to be set by the ./check script (as evidenced by
execute_setup_common(), which checks for test_dir and
qemu_default_machine to be set, and aborts if they are not).

Using .get() this way has the disadvantage of returning an Optional[str]
type, which mypy will complain about when tests just assume these values
to be str.

Use [] instead, which raises a KeyError for environment variables that
are not set.  When this exception is raised, catch it and move the abort
code from execute_setup_common() there.

Drop the 'assert iotests.sock_dir is not None' from iotest 300, because
that sort of thing is precisely what this patch wants to prevent.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210118105720.14824-2-mreitz@redhat.com>
---
 tests/qemu-iotests/300        |  1 -
 tests/qemu-iotests/iotests.py | 26 +++++++++++++-------------
 2 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/tests/qemu-iotests/300 b/tests/qemu-iotests/300
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/300
+++ b/tests/qemu-iotests/300
@@ -XXX,XX +XXX,XX @@ import qemu
 
 BlockBitmapMapping = List[Dict[str, Union[str, List[Dict[str, str]]]]]
 
-assert iotests.sock_dir is not None
 mig_sock = os.path.join(iotests.sock_dir, 'mig_sock')
 
 
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -XXX,XX +XXX,XX @@ qemu_opts = os.environ.get('QEMU_OPTIONS', '').strip().split(' ')
 
 imgfmt = os.environ.get('IMGFMT', 'raw')
 imgproto = os.environ.get('IMGPROTO', 'file')
-test_dir = os.environ.get('TEST_DIR')
-sock_dir = os.environ.get('SOCK_DIR')
 output_dir = os.environ.get('OUTPUT_DIR', '.')
-cachemode = os.environ.get('CACHEMODE')
-aiomode = os.environ.get('AIOMODE')
-qemu_default_machine = os.environ.get('QEMU_DEFAULT_MACHINE')
+
+try:
+    test_dir = os.environ['TEST_DIR']
+    sock_dir = os.environ['SOCK_DIR']
+    cachemode = os.environ['CACHEMODE']
+    aiomode = os.environ['AIOMODE']
+    qemu_default_machine = os.environ['QEMU_DEFAULT_MACHINE']
+except KeyError:
+    # We are using these variables as proxies to indicate that we're
+    # not being run via "check". There may be other things set up by
+    # "check" that individual test cases rely on.
+    sys.stderr.write('Please run this test via the "check" script\n')
+    sys.exit(os.EX_USAGE)
 
 socket_scm_helper = os.environ.get('SOCKET_SCM_HELPER', 'socket_scm_helper')
 
@@ -XXX,XX +XXX,XX @@ def execute_setup_common(supported_fmts: Sequence[str] = (),
     """
     # Note: Python 3.6 and pylint do not like 'Collection' so use 'Sequence'.
 
-    # We are using TEST_DIR and QEMU_DEFAULT_MACHINE as proxies to
-    # indicate that we're not being run via "check". There may be
-    # other things set up by "check" that individual test cases rely
-    # on.
-    if test_dir is None or qemu_default_machine is None:
-        sys.stderr.write('Please run this test via the "check" script\n')
-        sys.exit(os.EX_USAGE)
-
     debug = '-d' in sys.argv
     if debug:
         sys.argv.remove('-d')
-- 
2.29.2

Instead of checking iotests.py only, check all Python files in the
qemu-iotests/ directory.  Of course, most of them do not pass, so there
is an extensive skip list for now.  (The only files that do pass are
209, 254, 283, and iotests.py.)

(Alternatively, we could have the opposite, i.e. an explicit list of
files that we do want to check, but I think it is better to check files
by default.)

Unless started in debug mode (./check -d), the output has no information
on which files are tested, so we will not have a problem e.g. with
backports, where some files may be missing when compared to upstream.

Besides the technical rewrite, some more things are changed:

- For the pylint invocation, PYTHONPATH is adjusted.  This mirrors
  setting MYPYPATH for mypy.

- Also, MYPYPATH is now derived from PYTHONPATH, so that we include
  paths set by the environment.  Maybe at some point we want to let the
  check script add '../../python/' to PYTHONPATH so that iotests.py does
  not need to do that.

- Passing --notes=FIXME,XXX to pylint suppresses warnings for TODO
  comments.  TODO is fine, we do not need 297 to complain about such
  comments.

- The "Success" line from mypy's output is suppressed, because (A) it
  does not add useful information, and (B) it would leak information
  about the files having been tested to the reference output, which we
  decidedly do not want.

Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210118105720.14824-3-mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 tests/qemu-iotests/297     | 112 +++++++++++++++++++++++++++++--------
 tests/qemu-iotests/297.out |   5 +-
 2 files changed, 92 insertions(+), 25 deletions(-)

diff --git a/tests/qemu-iotests/297 b/tests/qemu-iotests/297
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/297
+++ b/tests/qemu-iotests/297
@@ -XXX,XX +XXX,XX @@
-#!/usr/bin/env bash
+#!/usr/bin/env python3
 # group: meta
 #
 # Copyright (C) 2020 Red Hat, Inc.
@@ -XXX,XX +XXX,XX @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-seq=$(basename $0)
-echo "QA output created by $seq"
+import os
+import re
+import shutil
+import subprocess
+import sys
 
-status=1	# failure is the default!
+import iotests
 
-# get standard environment
-. ./common.rc
 
-if ! type -p "pylint-3" > /dev/null; then
-    _notrun "pylint-3 not found"
-fi
-if ! type -p "mypy" > /dev/null; then
-    _notrun "mypy not found"
-fi
+# TODO: Empty this list!
+SKIP_FILES = (
+    '030', '040', '041', '044', '045', '055', '056', '057', '065', '093',
+    '096', '118', '124', '129', '132', '136', '139', '147', '148', '149',
+    '151', '152', '155', '163', '165', '169', '194', '196', '199', '202',
+    '203', '205', '206', '207', '208', '210', '211', '212', '213', '216',
+    '218', '219', '222', '224', '228', '234', '235', '236', '237', '238',
+    '240', '242', '245', '246', '248', '255', '256', '257', '258', '260',
+    '262', '264', '266', '274', '277', '280', '281', '295', '296', '298',
+    '299', '300', '302', '303', '304', '307',
+    'nbd-fault-injector.py', 'qcow2.py', 'qcow2_format.py', 'qed.py'
+)
 
-pylint-3 --score=n iotests.py
 
-MYPYPATH=../../python/ mypy --warn-unused-configs --disallow-subclassing-any \
-    --disallow-any-generics --disallow-incomplete-defs \
-    --disallow-untyped-decorators --no-implicit-optional \
-    --warn-redundant-casts --warn-unused-ignores \
-    --no-implicit-reexport iotests.py
+def is_python_file(filename):
+    if not os.path.isfile(filename):
+        return False
 
-# success, all done
-echo "*** done"
-rm -f $seq.full
-status=0
+    if filename.endswith('.py'):
+        return True
+
+    with open(filename) as f:
+        try:
+            first_line = f.readline()
+            return re.match('^#!.*python', first_line) is not None
+        except UnicodeDecodeError:  # Ignore binary files
+            return False
+
+
+def run_linters():
+    files = [filename for filename in (set(os.listdir('.')) - set(SKIP_FILES))
+             if is_python_file(filename)]
+
+    iotests.logger.debug('Files to be checked:')
+    iotests.logger.debug(', '.join(sorted(files)))
+
+    print('=== pylint ===')
+    sys.stdout.flush()
+
+    # Todo notes are fine, but fixme's or xxx's should probably just be
+    # fixed (in tests, at least)
+    env = os.environ.copy()
+    qemu_module_path = os.path.join(os.path.dirname(__file__),
+                                    '..', '..', 'python')
+    try:
+        env['PYTHONPATH'] += os.pathsep + qemu_module_path
+    except KeyError:
+        env['PYTHONPATH'] = qemu_module_path
+    subprocess.run(('pylint-3', '--score=n', '--notes=FIXME,XXX', *files),
+                   env=env, check=False)
+
+    print('=== mypy ===')
+    sys.stdout.flush()
+
+    # We have to call mypy separately for each file.  Otherwise, it
+    # will interpret all given files as belonging together (i.e., they
+    # may not both define the same classes, etc.; most notably, they
+    # must not both define the __main__ module).
+    env['MYPYPATH'] = env['PYTHONPATH']
+    for filename in files:
+        p = subprocess.run(('mypy',
+                            '--warn-unused-configs',
+                            '--disallow-subclassing-any',
+                            '--disallow-any-generics',
+                            '--disallow-incomplete-defs',
+                            '--disallow-untyped-decorators',
+                            '--no-implicit-optional',
+                            '--warn-redundant-casts',
+                            '--warn-unused-ignores',
+                            '--no-implicit-reexport',
+                            filename),
+                           env=env,
+                           check=False,
+                           stdout=subprocess.PIPE,
+                           stderr=subprocess.STDOUT,
+                           universal_newlines=True)
+
+        if p.returncode != 0:
+            print(p.stdout)
+
+
+for linter in ('pylint-3', 'mypy'):
+    if shutil.which(linter) is None:
+        iotests.notrun(f'{linter} not found')
+
+iotests.script_main(run_linters)
diff --git a/tests/qemu-iotests/297.out b/tests/qemu-iotests/297.out
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/297.out
+++ b/tests/qemu-iotests/297.out
@@ -XXX,XX +XXX,XX @@
-QA output created by 297
-Success: no issues found in 1 source file
-*** done
+=== pylint ===
+=== mypy ===
-- 
2.29.2

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210118105720.14824-4-mreitz@redhat.com>
---
 tests/qemu-iotests/124        |  8 +-------
 tests/qemu-iotests/iotests.py | 11 +++++++----
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/tests/qemu-iotests/124 b/tests/qemu-iotests/124
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/124
+++ b/tests/qemu-iotests/124
@@ -XXX,XX +XXX,XX @@
 
 import os
 import iotests
+from iotests import try_remove
 
 
 def io_write_patterns(img, patterns):
@@ -XXX,XX +XXX,XX @@ def io_write_patterns(img, patterns):
         iotests.qemu_io('-c', 'write -P%s %s %s' % pattern, img)
 
 
-def try_remove(img):
-    try:
-        os.remove(img)
-    except OSError:
-        pass
-
-
 def transaction_action(action, **kwargs):
     return {
         'type': action,
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -XXX,XX +XXX,XX @@ class FilePath:
         return False
 
 
+def try_remove(img):
+    try:
+        os.remove(img)
+    except OSError:
+        pass
+
 def file_path_remover():
     for path in reversed(file_path_remover.paths):
-        try:
-            os.remove(path)
-        except OSError:
-            pass
+        try_remove(path)
 
 
 def file_path(*names, base_dir=test_dir):
-- 
2.29.2

@busy is false when the job is paused, which happens all the time
because that is how jobs yield (e.g. for mirror at least since commit
565ac01f8d3).

Back when 129 was added (2015), perhaps there was no better way of
checking whether the job was still actually running.  Now we have the
@status field (as of 58b295ba52c, i.e. 2018), which can give us exactly
that information.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210118105720.14824-6-mreitz@redhat.com>
---
 tests/qemu-iotests/129 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/129 b/tests/qemu-iotests/129
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/129
+++ b/tests/qemu-iotests/129
@@ -XXX,XX +XXX,XX @@ class TestStopWithBlockJob(iotests.QMPTestCase):
         result = self.vm.qmp("stop")
         self.assert_qmp(result, 'return', {})
         result = self.vm.qmp("query-block-jobs")
-        self.assert_qmp(result, 'return[0]/busy', True)
+        self.assert_qmp(result, 'return[0]/status', 'running')
         self.assert_qmp(result, 'return[0]/ready', False)
 
     def test_drive_mirror(self):
-- 
2.29.2

Throttling on the BB has not affected block jobs in a while, so it is
possible that one of the jobs in 129 finishes before the VM is stopped.
We can fix that by running the job from a throttle node.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210118105720.14824-7-mreitz@redhat.com>
---
 tests/qemu-iotests/129 | 37 +++++++++++++------------------------
 1 file changed, 13 insertions(+), 24 deletions(-)

diff --git a/tests/qemu-iotests/129 b/tests/qemu-iotests/129
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/129
+++ b/tests/qemu-iotests/129
@@ -XXX,XX +XXX,XX @@ class TestStopWithBlockJob(iotests.QMPTestCase):
         iotests.qemu_img('create', '-f', iotests.imgfmt, self.test_img,
                          "-b", self.base_img, '-F', iotests.imgfmt)
         iotests.qemu_io('-f', iotests.imgfmt, '-c', 'write -P0x5d 1M 128M', self.test_img)
-        self.vm = iotests.VM().add_drive(self.test_img)
+        self.vm = iotests.VM()
+        self.vm.add_object('throttle-group,id=tg0,x-bps-total=1024')
+
+        source_drive = 'driver=throttle,' \
+                       'throttle-group=tg0,' \
+                       f'file.driver={iotests.imgfmt},' \
+                       f'file.file.filename={self.test_img}'
+
+        self.vm.add_drive(None, source_drive)
         self.vm.launch()
 
     def tearDown(self):
-        params = {"device": "drive0",
-                  "bps": 0,
-                  "bps_rd": 0,
-                  "bps_wr": 0,
-                  "iops": 0,
-                  "iops_rd": 0,
-                  "iops_wr": 0,
-                 }
-        result = self.vm.qmp("block_set_io_throttle", conv_keys=False,
-                             **params)
         self.vm.shutdown()
         for img in (self.test_img, self.target_img, self.base_img):
             iotests.try_remove(img)
@@ -XXX,XX +XXX,XX @@ class TestStopWithBlockJob(iotests.QMPTestCase):
     def do_test_stop(self, cmd, **args):
         """Test 'stop' while block job is running on a throttled drive.
         The 'stop' command shouldn't drain the job"""
-        params = {"device": "drive0",
-                  "bps": 1024,
-                  "bps_rd": 0,
-                  "bps_wr": 0,
-                  "iops": 0,
-                  "iops_rd": 0,
-                  "iops_wr": 0,
-                 }
-        result = self.vm.qmp("block_set_io_throttle", conv_keys=False,
-                             **params)
-        self.assert_qmp(result, 'return', {})
         result = self.vm.qmp(cmd, **args)
         self.assert_qmp(result, 'return', {})
+
         result = self.vm.qmp("stop")
         self.assert_qmp(result, 'return', {})
         result = self.vm.qmp("query-block-jobs")
+
         self.assert_qmp(result, 'return[0]/status', 'running')
         self.assert_qmp(result, 'return[0]/ready', False)
 
     def test_drive_mirror(self):
         self.do_test_stop("drive-mirror", device="drive0",
-                          target=self.target_img,
+                          target=self.target_img, format=iotests.imgfmt,
                           sync="full")
 
     def test_drive_backup(self):
         self.do_test_stop("drive-backup", device="drive0",
-                          target=self.target_img,
+                          target=self.target_img, format=iotests.imgfmt,
                           sync="full")
 
     def test_block_commit(self):
-- 
2.29.2

Before this patch, test_block_commit() performs an active commit, which
under the hood is a mirror job.  If we want to test various different
block jobs, we should perhaps run an actual commit job instead.

Doing so requires adding an overlay above the source node before the
commit is done (and then specifying the source node as the top node for
the commit job).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210118105720.14824-8-mreitz@redhat.com>
---
 tests/qemu-iotests/129 | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/tests/qemu-iotests/129 b/tests/qemu-iotests/129
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/129
+++ b/tests/qemu-iotests/129
@@ -XXX,XX +XXX,XX @@ class TestStopWithBlockJob(iotests.QMPTestCase):
     test_img = os.path.join(iotests.test_dir, 'test.img')
     target_img = os.path.join(iotests.test_dir, 'target.img')
     base_img = os.path.join(iotests.test_dir, 'base.img')
+    overlay_img = os.path.join(iotests.test_dir, 'overlay.img')
 
     def setUp(self):
         iotests.qemu_img('create', '-f', iotests.imgfmt, self.base_img, "1G")
@@ -XXX,XX +XXX,XX @@ class TestStopWithBlockJob(iotests.QMPTestCase):
         self.vm.add_object('throttle-group,id=tg0,x-bps-total=1024')
 
         source_drive = 'driver=throttle,' \
+                       'node-name=source,' \
                        'throttle-group=tg0,' \
                        f'file.driver={iotests.imgfmt},' \
                        f'file.file.filename={self.test_img}'
@@ -XXX,XX +XXX,XX @@ class TestStopWithBlockJob(iotests.QMPTestCase):
 
     def tearDown(self):
         self.vm.shutdown()
-        for img in (self.test_img, self.target_img, self.base_img):
+        for img in (self.test_img, self.target_img, self.base_img,
+                    self.overlay_img):
             iotests.try_remove(img)
 
     def do_test_stop(self, cmd, **args):
@@ -XXX,XX +XXX,XX @@ class TestStopWithBlockJob(iotests.QMPTestCase):
                           sync="full")
 
     def test_block_commit(self):
-        self.do_test_stop("block-commit", device="drive0")
+        # Add overlay above the source node so that we actually use a
+        # commit job instead of a mirror job
+
+        iotests.qemu_img('create', '-f', iotests.imgfmt, self.overlay_img,
+                         '1G')
+
+        result = self.vm.qmp('blockdev-add', **{
+                                 'node-name': 'overlay',
+                                 'driver': iotests.imgfmt,
+                                 'file': {
+                                     'driver': 'file',
+                                     'filename': self.overlay_img
+                                 }
+                             })
+        self.assert_qmp(result, 'return', {})
+
+        result = self.vm.qmp('blockdev-snapshot',
+                             node='source', overlay='overlay')
+        self.assert_qmp(result, 'return', {})
+
+        self.do_test_stop('block-commit', device='drive0', top_node='source')
 
 if __name__ == '__main__':
     iotests.main(supported_fmts=["qcow2"],
-- 
2.29.2

Issuing 'stop' on the VM drains all nodes.  If the mirror job has many
large requests in flight, this may lead to significant I/O that looks a
bit like 'stop' would make the job try to complete (which is what 129
should verify not to happen).

We can limit the I/O in flight by limiting the buffer size, so mirror
will make very little progress during the 'stop' drain.

(We do not need to do anything about commit, which has a buffer size of
512 kB by default; or backup, which goes cluster by cluster.  Once we
have asynchronous requests for backup, that will change, but then we can
fine-tune the backup job to only perform a single request on a very
small chunk, too.)

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210118105720.14824-9-mreitz@redhat.com>
---
 tests/qemu-iotests/129 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/129 b/tests/qemu-iotests/129
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/129
+++ b/tests/qemu-iotests/129
@@ -XXX,XX +XXX,XX @@ class TestStopWithBlockJob(iotests.QMPTestCase):
     def test_drive_mirror(self):
         self.do_test_stop("drive-mirror", device="drive0",
                           target=self.target_img, format=iotests.imgfmt,
-                          sync="full")
+                          sync="full", buf_size=65536)
 
     def test_drive_backup(self):
         self.do_test_stop("drive-backup", device="drive0",
-- 
2.29.2

And consequentially drop it from 297's skip list.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210118105720.14824-10-mreitz@redhat.com>
---
 tests/qemu-iotests/129 | 4 ++--
 tests/qemu-iotests/297 | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/qemu-iotests/129 b/tests/qemu-iotests/129
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/129
+++ b/tests/qemu-iotests/129
@@ -XXX,XX +XXX,XX @@
 
 import os
 import iotests
-import time
 
 class TestStopWithBlockJob(iotests.QMPTestCase):
     test_img = os.path.join(iotests.test_dir, 'test.img')
@@ -XXX,XX +XXX,XX @@ class TestStopWithBlockJob(iotests.QMPTestCase):
         iotests.qemu_img('create', '-f', iotests.imgfmt, self.base_img, "1G")
         iotests.qemu_img('create', '-f', iotests.imgfmt, self.test_img,
                          "-b", self.base_img, '-F', iotests.imgfmt)
-        iotests.qemu_io('-f', iotests.imgfmt, '-c', 'write -P0x5d 1M 128M', self.test_img)
+        iotests.qemu_io('-f', iotests.imgfmt, '-c', 'write -P0x5d 1M 128M',
+                        self.test_img)
         self.vm = iotests.VM()
         self.vm.add_object('throttle-group,id=tg0,x-bps-total=1024')
 
diff --git a/tests/qemu-iotests/297 b/tests/qemu-iotests/297
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/297
+++ b/tests/qemu-iotests/297
@@ -XXX,XX +XXX,XX @@ import iotests
 # TODO: Empty this list!
 SKIP_FILES = (
     '030', '040', '041', '044', '045', '055', '056', '057', '065', '093',
-    '096', '118', '124', '129', '132', '136', '139', '147', '148', '149',
+    '096', '118', '124', '132', '136', '139', '147', '148', '149',
     '151', '152', '155', '163', '165', '169', '194', '196', '199', '202',
     '203', '205', '206', '207', '208', '210', '211', '212', '213', '216',
     '218', '219', '222', '224', '228', '234', '235', '236', '237', '238',
-- 
2.29.2

And consequentially drop it from 297's skip list.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210118105720.14824-11-mreitz@redhat.com>
---
 tests/qemu-iotests/297 |  2 +-
 tests/qemu-iotests/300 | 18 +++++++++++++++---
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/tests/qemu-iotests/297 b/tests/qemu-iotests/297
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/297
+++ b/tests/qemu-iotests/297
@@ -XXX,XX +XXX,XX @@ SKIP_FILES = (
     '218', '219', '222', '224', '228', '234', '235', '236', '237', '238',
     '240', '242', '245', '246', '248', '255', '256', '257', '258', '260',
     '262', '264', '266', '274', '277', '280', '281', '295', '296', '298',
-    '299', '300', '302', '303', '304', '307',
+    '299', '302', '303', '304', '307',
     'nbd-fault-injector.py', 'qcow2.py', 'qcow2_format.py', 'qed.py'
 )
 
diff --git a/tests/qemu-iotests/300 b/tests/qemu-iotests/300
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/300
+++ b/tests/qemu-iotests/300
@@ -XXX,XX +XXX,XX @@ import os
 import random
 import re
 from typing import Dict, List, Optional, Union
+
 import iotests
+
+# Import qemu after iotests.py has amended sys.path
+# pylint: disable=wrong-import-order
 import qemu
 
 BlockBitmapMapping = List[Dict[str, Union[str, List[Dict[str, str]]]]]
@@ -XXX,XX +XXX,XX @@ class TestDirtyBitmapMigration(iotests.QMPTestCase):
         If @msg is None, check that there has not been any error.
         """
         self.vm_b.shutdown()
+
+        log = self.vm_b.get_log()
+        assert log is not None  # Loaded after shutdown
+
         if msg is None:
-            self.assertNotIn('qemu-system-', self.vm_b.get_log())
+            self.assertNotIn('qemu-system-', log)
         else:
-            self.assertIn(msg, self.vm_b.get_log())
+            self.assertIn(msg, log)
 
     @staticmethod
     def mapping(node_name: str, node_alias: str,
@@ -XXX,XX +XXX,XX @@ class TestBlockBitmapMappingErrors(TestDirtyBitmapMigration):
 
         # Check for the error in the source's log
         self.vm_a.shutdown()
+
+        log = self.vm_a.get_log()
+        assert log is not None  # Loaded after shutdown
+
         self.assertIn(f"Cannot migrate bitmap '{name}' on node "
                       f"'{self.src_node_name}': Name is longer than 255 bytes",
-                      self.vm_a.get_log())
+                      log)
 
         # Expect abnormal shutdown of the destination VM because of
         # the failed migration
-- 
2.29.2

Disposition (action) for any given signal is global for the process.
When two threads run coroutine-sigaltstack's qemu_coroutine_new()
concurrently, they may interfere with each other: One of them may revert
the SIGUSR2 handler to SIG_DFL, between the other thread (a) setting up
coroutine_trampoline() as the handler and (b) raising SIGUSR2.  That
SIGUSR2 will then terminate the QEMU process abnormally.

We have to ensure that only one thread at a time can modify the
process-global SIGUSR2 handler.  To do so, wrap the whole section where
that is done in a mutex.

Alternatively, we could for example have the SIGUSR2 handler always be
coroutine_trampoline(), so there would be no need to invoke sigaction()
in qemu_coroutine_new().  Laszlo has posted a patch to do so here:

https://lists.nongnu.org/archive/html/qemu-devel/2021-01/msg05962.html

However, given that coroutine-sigaltstack is more of a fallback
implementation for platforms that do not support ucontext, that change
may be a bit too invasive to be comfortable with it.  The mutex proposed
here may negatively impact performance, but the change is much simpler.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210125120305.19520-1-mreitz@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 util/coroutine-sigaltstack.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/util/coroutine-sigaltstack.c b/util/coroutine-sigaltstack.c
index XXXXXXX..XXXXXXX 100644
--- a/util/coroutine-sigaltstack.c
+++ b/util/coroutine-sigaltstack.c
@@ -XXX,XX +XXX,XX @@ Coroutine *qemu_coroutine_new(void)
     sigset_t sigs;
     sigset_t osigs;
     sigjmp_buf old_env;
+    static pthread_mutex_t sigusr2_mutex = PTHREAD_MUTEX_INITIALIZER;
 
     /* The way to manipulate stack is with the sigaltstack function. We
      * prepare a stack, with it delivering a signal to ourselves and then
@@ -XXX,XX +XXX,XX @@ Coroutine *qemu_coroutine_new(void)
     sa.sa_handler = coroutine_trampoline;
     sigfillset(&sa.sa_mask);
     sa.sa_flags = SA_ONSTACK;
+
+    /*
+     * sigaction() is a process-global operation.  We must not run
+     * this code in multiple threads at once.
+     */
+    pthread_mutex_lock(&sigusr2_mutex);
     if (sigaction(SIGUSR2, &sa, &osa) != 0) {
         abort();
     }
@@ -XXX,XX +XXX,XX @@ Coroutine *qemu_coroutine_new(void)
      * Restore the old SIGUSR2 signal handler and mask
      */
     sigaction(SIGUSR2, &osa, NULL);
+    pthread_mutex_unlock(&sigusr2_mutex);
+
     pthread_sigmask(SIG_SETMASK, &osigs, NULL);
 
     /*
-- 
2.29.2

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

Experiments show, that copy_range is not always making things faster.
So, to make experimentation simpler, let's add a parameter. Some more
perf parameters will be added soon, so here is a new struct.

For now, add new backup qmp parameter with x- prefix for the following
reasons:

- We are going to add more performance parameters, some will be
   related to the whole block-copy process, some only to background
   copying in backup (ignored for copy-before-write operations).
 - On the other hand, we are going to use block-copy interface in other
   block jobs, which will need performance options as well.. And it
   should be the same structure or at least somehow related.

So, there are too much unclean things about how the interface and now
we need the new options mostly for testing. Let's keep them
experimental for a while.

In do_backup_common() new x-perf parameter handled in a way to
make further options addition simpler.

We add use-copy-range with default=true, and we'll change the default
in further patch, after moving backup to use block-copy.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-2-vsementsov@virtuozzo.com>
[mreitz: s/5\.2/6.0/]
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 qapi/block-core.json       | 17 ++++++++++++++++-
 block/backup-top.h         |  1 +
 include/block/block-copy.h |  2 +-
 include/block/block_int.h  |  3 +++
 block/backup-top.c         |  4 +++-
 block/backup.c             |  6 +++++-
 block/block-copy.c         |  4 ++--
 block/replication.c        |  2 ++
 blockdev.c                 |  8 ++++++++
 9 files changed, 41 insertions(+), 6 deletions(-)

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 @@
 { 'struct': 'BlockdevSnapshot',
   'data': { 'node': 'str', 'overlay': 'str' } }
 
+##
+# @BackupPerf:
+#
+# Optional parameters for backup. These parameters don't affect
+# functionality, but may significantly affect performance.
+#
+# @use-copy-range: Use copy offloading. Default true.
+#
+# Since: 6.0
+##
+{ 'struct': 'BackupPerf',
+  'data': { '*use-copy-range': 'bool' }}
+
 ##
 # @BackupCommon:
 #
@@ -XXX,XX +XXX,XX @@
 #                    above node specified by @drive. If this option is not given,
 #                    a node name is autogenerated. (Since: 4.2)
 #
+# @x-perf: Performance options. (Since 6.0)
+#
 # Note: @on-source-error and @on-target-error only affect background
 #       I/O.  If an error occurs during a guest write request, the device's
 #       rerror/werror actions will be used.
@@ -XXX,XX +XXX,XX @@
             '*on-source-error': 'BlockdevOnError',
             '*on-target-error': 'BlockdevOnError',
             '*auto-finalize': 'bool', '*auto-dismiss': 'bool',
-            '*filter-node-name': 'str' } }
+            '*filter-node-name': 'str', '*x-perf': 'BackupPerf'  } }
 
 ##
 # @DriveBackup:
diff --git a/block/backup-top.h b/block/backup-top.h
index XXXXXXX..XXXXXXX 100644
--- a/block/backup-top.h
+++ b/block/backup-top.h
@@ -XXX,XX +XXX,XX @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
                                          BlockDriverState *target,
                                          const char *filter_node_name,
                                          uint64_t cluster_size,
+                                         BackupPerf *perf,
                                          BdrvRequestFlags write_flags,
                                          BlockCopyState **bcs,
                                          Error **errp);
diff --git a/include/block/block-copy.h b/include/block/block-copy.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/block-copy.h
+++ b/include/block/block-copy.h
@@ -XXX,XX +XXX,XX @@ typedef void (*ProgressBytesCallbackFunc)(int64_t bytes, void *opaque);
 typedef struct BlockCopyState BlockCopyState;
 
 BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
-                                     int64_t cluster_size,
+                                     int64_t cluster_size, bool use_copy_range,
                                      BdrvRequestFlags write_flags,
                                      Error **errp);
 
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 @@ void mirror_start(const char *job_id, BlockDriverState *bs,
  * @sync_mode: What parts of the disk image should be copied to the destination.
  * @sync_bitmap: The dirty bitmap if sync_mode is 'bitmap' or 'incremental'
  * @bitmap_mode: The bitmap synchronization policy to use.
+ * @perf: Performance options. All actual fields assumed to be present,
+ *        all ".has_*" fields are ignored.
  * @on_source_error: The action to take upon error reading from the source.
  * @on_target_error: The action to take upon error writing to the target.
  * @creation_flags: Flags that control the behavior of the Job lifetime.
@@ -XXX,XX +XXX,XX @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
                             BitmapSyncMode bitmap_mode,
                             bool compress,
                             const char *filter_node_name,
+                            BackupPerf *perf,
                             BlockdevOnError on_source_error,
                             BlockdevOnError on_target_error,
                             int creation_flags,
diff --git a/block/backup-top.c b/block/backup-top.c
index XXXXXXX..XXXXXXX 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -XXX,XX +XXX,XX @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
                                          BlockDriverState *target,
                                          const char *filter_node_name,
                                          uint64_t cluster_size,
+                                         BackupPerf *perf,
                                          BdrvRequestFlags write_flags,
                                          BlockCopyState **bcs,
                                          Error **errp)
@@ -XXX,XX +XXX,XX @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
 
     state->cluster_size = cluster_size;
     state->bcs = block_copy_state_new(top->backing, state->target,
-                                      cluster_size, write_flags, &local_err);
+                                      cluster_size, perf->use_copy_range,
+                                      write_flags, &local_err);
     if (local_err) {
         error_prepend(&local_err, "Cannot create block-copy-state: ");
         goto fail;
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 @@ typedef struct BackupBlockJob {
     uint64_t len;
     uint64_t bytes_read;
     int64_t cluster_size;
+    BackupPerf perf;
 
     BlockCopyState *bcs;
 } BackupBlockJob;
@@ -XXX,XX +XXX,XX @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
                   BitmapSyncMode bitmap_mode,
                   bool compress,
                   const char *filter_node_name,
+                  BackupPerf *perf,
                   BlockdevOnError on_source_error,
                   BlockdevOnError on_target_error,
                   int creation_flags,
@@ -XXX,XX +XXX,XX @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
                   (compress ? BDRV_REQ_WRITE_COMPRESSED : 0),
 
     backup_top = bdrv_backup_top_append(bs, target, filter_node_name,
-                                        cluster_size, write_flags, &bcs, errp);
+                                        cluster_size, perf,
+                                        write_flags, &bcs, errp);
     if (!backup_top) {
         goto error;
     }
@@ -XXX,XX +XXX,XX @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
     job->bcs = bcs;
     job->cluster_size = cluster_size;
     job->len = len;
+    job->perf = *perf;
 
     block_copy_set_progress_callback(bcs, backup_progress_bytes_callback, job);
     block_copy_set_progress_meter(bcs, &job->common.job.progress);
diff --git a/block/block-copy.c b/block/block-copy.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -XXX,XX +XXX,XX @@ static uint32_t block_copy_max_transfer(BdrvChild *source, BdrvChild *target)
 }
 
 BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
-                                     int64_t cluster_size,
+                                     int64_t cluster_size, bool use_copy_range,
                                      BdrvRequestFlags write_flags, Error **errp)
 {
     BlockCopyState *s;
@@ -XXX,XX +XXX,XX @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
          * We enable copy-range, but keep small copy_size, until first
          * successful copy_range (look at block_copy_do_copy).
          */
-        s->use_copy_range = true;
+        s->use_copy_range = use_copy_range;
         s->copy_size = MAX(s->cluster_size, BLOCK_COPY_MAX_BUFFER);
     }
 
diff --git a/block/replication.c b/block/replication.c
index XXXXXXX..XXXXXXX 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -XXX,XX +XXX,XX @@ static void replication_start(ReplicationState *rs, ReplicationMode mode,
     int64_t active_length, hidden_length, disk_length;
     AioContext *aio_context;
     Error *local_err = NULL;
+    BackupPerf perf = { .use_copy_range = true };
 
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
@@ -XXX,XX +XXX,XX @@ static void replication_start(ReplicationState *rs, ReplicationMode mode,
         s->backup_job = backup_job_create(
                                 NULL, s->secondary_disk->bs, s->hidden_disk->bs,
                                 0, MIRROR_SYNC_MODE_NONE, NULL, 0, false, NULL,
+                                &perf,
                                 BLOCKDEV_ON_ERROR_REPORT,
                                 BLOCKDEV_ON_ERROR_REPORT, JOB_INTERNAL,
                                 backup_job_completed, bs, NULL, &local_err);
diff --git a/blockdev.c b/blockdev.c
index XXXXXXX..XXXXXXX 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -XXX,XX +XXX,XX @@ static BlockJob *do_backup_common(BackupCommon *backup,
 {
     BlockJob *job = NULL;
     BdrvDirtyBitmap *bmap = NULL;
+    BackupPerf perf = { .use_copy_range = true };
     int job_flags = JOB_DEFAULT;
 
     if (!backup->has_speed) {
@@ -XXX,XX +XXX,XX @@ static BlockJob *do_backup_common(BackupCommon *backup,
         backup->compress = false;
     }
 
+    if (backup->x_perf) {
+        if (backup->x_perf->has_use_copy_range) {
+            perf.use_copy_range = backup->x_perf->use_copy_range;
+        }
+    }
+
     if ((backup->sync == MIRROR_SYNC_MODE_BITMAP) ||
         (backup->sync == MIRROR_SYNC_MODE_INCREMENTAL)) {
         /* done before desugaring 'incremental' to print the right message */
@@ -XXX,XX +XXX,XX @@ static BlockJob *do_backup_common(BackupCommon *backup,
                             backup->sync, bmap, backup->bitmap_mode,
                             backup->compress,
                             backup->filter_node_name,
+                            &perf,
                             backup->on_source_error,
                             backup->on_target_error,
                             job_flags, NULL, NULL, txn, errp);
-- 
2.29.2

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

Refactor common path to use BlockCopyCallState pointer as parameter, to
prepare it for use in asynchronous block-copy (at least, we'll need to
run block-copy in a coroutine, passing the whole parameters as one
pointer).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-3-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/block-copy.c | 51 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 38 insertions(+), 13 deletions(-)

diff --git a/block/block-copy.c b/block/block-copy.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -XXX,XX +XXX,XX @@
 static coroutine_fn int block_copy_task_entry(AioTask *task);
 
 typedef struct BlockCopyCallState {
+    /* IN parameters */
+    BlockCopyState *s;
+    int64_t offset;
+    int64_t bytes;
+
+    /* State */
     bool failed;
+
+    /* OUT parameters */
     bool error_is_read;
 } BlockCopyCallState;
 
@@ -XXX,XX +XXX,XX @@ int64_t block_copy_reset_unallocated(BlockCopyState *s,
  * Returns 1 if dirty clusters found and successfully copied, 0 if no dirty
  * clusters found and -errno on failure.
  */
-static int coroutine_fn block_copy_dirty_clusters(BlockCopyState *s,
-                                                  int64_t offset, int64_t bytes,
-                                                  bool *error_is_read)
+static int coroutine_fn
+block_copy_dirty_clusters(BlockCopyCallState *call_state)
 {
+    BlockCopyState *s = call_state->s;
+    int64_t offset = call_state->offset;
+    int64_t bytes = call_state->bytes;
+
     int ret = 0;
     bool found_dirty = false;
     int64_t end = offset + bytes;
     AioTaskPool *aio = NULL;
-    BlockCopyCallState call_state = {false, false};
 
     /*
      * block_copy() user is responsible for keeping source and target in same
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn block_copy_dirty_clusters(BlockCopyState *s,
         BlockCopyTask *task;
         int64_t status_bytes;
 
-        task = block_copy_task_create(s, &call_state, offset, bytes);
+        task = block_copy_task_create(s, call_state, offset, bytes);
         if (!task) {
             /* No more dirty bits in the bitmap */
             trace_block_copy_skip_range(s, offset, bytes);
@@ -XXX,XX +XXX,XX @@ out:
 
         aio_task_pool_free(aio);
     }
-    if (error_is_read && ret < 0) {
-        *error_is_read = call_state.error_is_read;
-    }
 
     return ret < 0 ? ret : found_dirty;
 }
 
 /*
- * block_copy
+ * block_copy_common
  *
  * Copy requested region, accordingly to dirty bitmap.
  * Collaborate with parallel block_copy requests: if they succeed it will help
@@ -XXX,XX +XXX,XX @@ out:
  * it means that some I/O operation failed in context of _this_ block_copy call,
  * not some parallel operation.
  */
-int coroutine_fn block_copy(BlockCopyState *s, int64_t offset, int64_t bytes,
-                            bool *error_is_read)
+static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
 {
     int ret;
 
     do {
-        ret = block_copy_dirty_clusters(s, offset, bytes, error_is_read);
+        ret = block_copy_dirty_clusters(call_state);
 
         if (ret == 0) {
-            ret = block_copy_wait_one(s, offset, bytes);
+            ret = block_copy_wait_one(call_state->s, call_state->offset,
+                                      call_state->bytes);
         }
 
         /*
@@ -XXX,XX +XXX,XX @@ int coroutine_fn block_copy(BlockCopyState *s, int64_t offset, int64_t bytes,
     return ret;
 }
 
+int coroutine_fn block_copy(BlockCopyState *s, int64_t start, int64_t bytes,
+                            bool *error_is_read)
+{
+    BlockCopyCallState call_state = {
+        .s = s,
+        .offset = start,
+        .bytes = bytes,
+    };
+
+    int ret = block_copy_common(&call_state);
+
+    if (error_is_read && ret < 0) {
+        *error_is_read = call_state.error_is_read;
+    }
+
+    return ret;
+}
+
 BdrvDirtyBitmap *block_copy_dirty_bitmap(BlockCopyState *s)
 {
     return s->copy_bitmap;
-- 
2.29.2

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

We'll need async block-copy invocation to use in backup directly.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-4-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block-copy.h | 29 ++++++++++++++
 block/block-copy.c         | 81 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 106 insertions(+), 4 deletions(-)

diff --git a/include/block/block-copy.h b/include/block/block-copy.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/block-copy.h
+++ b/include/block/block-copy.h
@@ -XXX,XX +XXX,XX @@
 #include "qemu/co-shared-resource.h"
 
 typedef void (*ProgressBytesCallbackFunc)(int64_t bytes, void *opaque);
+typedef void (*BlockCopyAsyncCallbackFunc)(void *opaque);
 typedef struct BlockCopyState BlockCopyState;
+typedef struct BlockCopyCallState BlockCopyCallState;
 
 BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
                                      int64_t cluster_size, bool use_copy_range,
@@ -XXX,XX +XXX,XX @@ int64_t block_copy_reset_unallocated(BlockCopyState *s,
 int coroutine_fn block_copy(BlockCopyState *s, int64_t offset, int64_t bytes,
                             bool *error_is_read);
 
+/*
+ * Run block-copy in a coroutine, create corresponding BlockCopyCallState
+ * object and return pointer to it. Never returns NULL.
+ *
+ * Caller is responsible to call block_copy_call_free() to free
+ * BlockCopyCallState object.
+ */
+BlockCopyCallState *block_copy_async(BlockCopyState *s,
+                                     int64_t offset, int64_t bytes,
+                                     BlockCopyAsyncCallbackFunc cb,
+                                     void *cb_opaque);
+
+/*
+ * Free finished BlockCopyCallState. Trying to free running
+ * block-copy will crash.
+ */
+void block_copy_call_free(BlockCopyCallState *call_state);
+
+/*
+ * Note, that block-copy call is marked finished prior to calling
+ * the callback.
+ */
+bool block_copy_call_finished(BlockCopyCallState *call_state);
+bool block_copy_call_succeeded(BlockCopyCallState *call_state);
+bool block_copy_call_failed(BlockCopyCallState *call_state);
+int block_copy_call_status(BlockCopyCallState *call_state, bool *error_is_read);
+
 BdrvDirtyBitmap *block_copy_dirty_bitmap(BlockCopyState *s);
 void block_copy_set_skip_unallocated(BlockCopyState *s, bool skip);
 
diff --git a/block/block-copy.c b/block/block-copy.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -XXX,XX +XXX,XX @@
 static coroutine_fn int block_copy_task_entry(AioTask *task);
 
 typedef struct BlockCopyCallState {
-    /* IN parameters */
+    /* IN parameters. Initialized in block_copy_async() and never changed. */
     BlockCopyState *s;
     int64_t offset;
     int64_t bytes;
+    BlockCopyAsyncCallbackFunc cb;
+    void *cb_opaque;
+
+    /* Coroutine where async block-copy is running */
+    Coroutine *co;
 
     /* State */
-    bool failed;
+    int ret;
+    bool finished;
 
     /* OUT parameters */
     bool error_is_read;
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int block_copy_task_entry(AioTask *task)
 
     ret = block_copy_do_copy(t->s, t->offset, t->bytes, t->zeroes,
                              &error_is_read);
-    if (ret < 0 && !t->call_state->failed) {
-        t->call_state->failed = true;
+    if (ret < 0 && !t->call_state->ret) {
+        t->call_state->ret = ret;
         t->call_state->error_is_read = error_is_read;
     } else {
         progress_work_done(t->s->progress, t->bytes);
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
          */
     } while (ret > 0);
 
+    call_state->finished = true;
+
+    if (call_state->cb) {
+        call_state->cb(call_state->cb_opaque);
+    }
+
     return ret;
 }
 
@@ -XXX,XX +XXX,XX @@ int coroutine_fn block_copy(BlockCopyState *s, int64_t start, int64_t bytes,
     return ret;
 }
 
+static void coroutine_fn block_copy_async_co_entry(void *opaque)
+{
+    block_copy_common(opaque);
+}
+
+BlockCopyCallState *block_copy_async(BlockCopyState *s,
+                                     int64_t offset, int64_t bytes,
+                                     BlockCopyAsyncCallbackFunc cb,
+                                     void *cb_opaque)
+{
+    BlockCopyCallState *call_state = g_new(BlockCopyCallState, 1);
+
+    *call_state = (BlockCopyCallState) {
+        .s = s,
+        .offset = offset,
+        .bytes = bytes,
+        .cb = cb,
+        .cb_opaque = cb_opaque,
+
+        .co = qemu_coroutine_create(block_copy_async_co_entry, call_state),
+    };
+
+    qemu_coroutine_enter(call_state->co);
+
+    return call_state;
+}
+
+void block_copy_call_free(BlockCopyCallState *call_state)
+{
+    if (!call_state) {
+        return;
+    }
+
+    assert(call_state->finished);
+    g_free(call_state);
+}
+
+bool block_copy_call_finished(BlockCopyCallState *call_state)
+{
+    return call_state->finished;
+}
+
+bool block_copy_call_succeeded(BlockCopyCallState *call_state)
+{
+    return call_state->finished && call_state->ret == 0;
+}
+
+bool block_copy_call_failed(BlockCopyCallState *call_state)
+{
+    return call_state->finished && call_state->ret < 0;
+}
+
+int block_copy_call_status(BlockCopyCallState *call_state, bool *error_is_read)
+{
+    assert(call_state->finished);
+    if (error_is_read) {
+        *error_is_read = call_state->error_is_read;
+    }
+    return call_state->ret;
+}
+
 BdrvDirtyBitmap *block_copy_dirty_bitmap(BlockCopyState *s)
 {
     return s->copy_bitmap;
-- 
2.29.2

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

They will be used for backup.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-5-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block-copy.h |  6 ++++++
 block/block-copy.c         | 11 +++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

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

It simplifies debugging.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-6-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/block-copy.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/block/block-copy.c b/block/block-copy.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -XXX,XX +XXX,XX @@ typedef struct BlockCopyCallState {
     /* Coroutine where async block-copy is running */
     Coroutine *co;
 
+    /* To reference all call states from BlockCopyState */
+    QLIST_ENTRY(BlockCopyCallState) list;
+
     /* State */
     int ret;
     bool finished;
@@ -XXX,XX +XXX,XX @@ typedef struct BlockCopyState {
     bool use_copy_range;
     int64_t copy_size;
     uint64_t len;
-    QLIST_HEAD(, BlockCopyTask) tasks;
+    QLIST_HEAD(, BlockCopyTask) tasks; /* All tasks from all block-copy calls */
+    QLIST_HEAD(, BlockCopyCallState) calls;
 
     BdrvRequestFlags write_flags;
 
@@ -XXX,XX +XXX,XX @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
     }
 
     QLIST_INIT(&s->tasks);
+    QLIST_INIT(&s->calls);
 
     return s;
 }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
 {
     int ret;
 
+    QLIST_INSERT_HEAD(&call_state->s->calls, call_state, list);
+
     do {
         ret = block_copy_dirty_clusters(call_state);
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
         call_state->cb(call_state->cb_opaque);
     }
 
+    QLIST_REMOVE(call_state, list);
+
     return ret;
 }
 
-- 
2.29.2

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

We are going to directly use one async block-copy operation for backup
job, so we need rate limiter.

We want to maintain current backup behavior: only background copying is
limited and copy-before-write operations only participate in limit
calculation. Therefore we need one rate limiter for block-copy state
and boolean flag for block-copy call state for actual limitation.

Note, that we can't just calculate each chunk in limiter after
successful copying: it will not save us from starting a lot of async
sub-requests which will exceed limit too much. Instead let's use the
following scheme on sub-request creation:
1. If at the moment limit is not exceeded, create the request and
account it immediately.
2. If at the moment limit is already exceeded, drop create sub-request
and handle limit instead (by sleep).
With this approach we'll never exceed the limit more than by one
sub-request (which pretty much matches current backup behavior).

Note also, that if there is in-flight block-copy async call,
block_copy_kick() should be used after set-speed to apply new setup
faster. For that block_copy_kick() published in this patch.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-7-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block-copy.h |  5 ++++-
 block/backup-top.c         |  2 +-
 block/backup.c             |  2 +-
 block/block-copy.c         | 46 +++++++++++++++++++++++++++++++++++++-
 4 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/include/block/block-copy.h b/include/block/block-copy.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/block-copy.h
+++ b/include/block/block-copy.h
@@ -XXX,XX +XXX,XX @@ int64_t block_copy_reset_unallocated(BlockCopyState *s,
                                      int64_t offset, int64_t *count);
 
 int coroutine_fn block_copy(BlockCopyState *s, int64_t offset, int64_t bytes,
-                            bool *error_is_read);
+                            bool ignore_ratelimit, bool *error_is_read);
 
 /*
  * Run block-copy in a coroutine, create corresponding BlockCopyCallState
@@ -XXX,XX +XXX,XX @@ bool block_copy_call_succeeded(BlockCopyCallState *call_state);
 bool block_copy_call_failed(BlockCopyCallState *call_state);
 int block_copy_call_status(BlockCopyCallState *call_state, bool *error_is_read);
 
+void block_copy_set_speed(BlockCopyState *s, uint64_t speed);
+void block_copy_kick(BlockCopyCallState *call_state);
+
 BdrvDirtyBitmap *block_copy_dirty_bitmap(BlockCopyState *s);
 void block_copy_set_skip_unallocated(BlockCopyState *s, bool skip);
 
diff --git a/block/backup-top.c b/block/backup-top.c
index XXXXXXX..XXXXXXX 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset,
     off = QEMU_ALIGN_DOWN(offset, s->cluster_size);
     end = QEMU_ALIGN_UP(offset + bytes, s->cluster_size);
 
-    return block_copy(s->bcs, off, end - off, NULL);
+    return block_copy(s->bcs, off, end - off, true, NULL);
 }
 
 static int coroutine_fn backup_top_co_pdiscard(BlockDriverState *bs,
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 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
 
     trace_backup_do_cow_enter(job, start, offset, bytes);
 
-    ret = block_copy(job->bcs, start, end - start, error_is_read);
+    ret = block_copy(job->bcs, start, end - start, true, error_is_read);
 
     trace_backup_do_cow_return(job, offset, bytes, ret);
 
diff --git a/block/block-copy.c b/block/block-copy.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -XXX,XX +XXX,XX @@
 #define BLOCK_COPY_MAX_BUFFER (1 * MiB)
 #define BLOCK_COPY_MAX_MEM (128 * MiB)
 #define BLOCK_COPY_MAX_WORKERS 64
+#define BLOCK_COPY_SLICE_TIME 100000000ULL /* ns */
 
 static coroutine_fn int block_copy_task_entry(AioTask *task);
 
@@ -XXX,XX +XXX,XX @@ typedef struct BlockCopyCallState {
     int64_t bytes;
     int max_workers;
     int64_t max_chunk;
+    bool ignore_ratelimit;
     BlockCopyAsyncCallbackFunc cb;
     void *cb_opaque;
 
@@ -XXX,XX +XXX,XX @@ typedef struct BlockCopyCallState {
     /* State */
     int ret;
     bool finished;
+    QemuCoSleepState *sleep_state;
 
     /* OUT parameters */
     bool error_is_read;
@@ -XXX,XX +XXX,XX @@ typedef struct BlockCopyState {
     void *progress_opaque;
 
     SharedResource *mem;
+
+    uint64_t speed;
+    RateLimit rate_limit;
 } BlockCopyState;
 
 static BlockCopyTask *find_conflicting_task(BlockCopyState *s,
@@ -XXX,XX +XXX,XX @@ block_copy_dirty_clusters(BlockCopyCallState *call_state)
         }
         task->zeroes = ret & BDRV_BLOCK_ZERO;
 
+        if (s->speed) {
+            if (!call_state->ignore_ratelimit) {
+                uint64_t ns = ratelimit_calculate_delay(&s->rate_limit, 0);
+                if (ns > 0) {
+                    block_copy_task_end(task, -EAGAIN);
+                    g_free(task);
+                    qemu_co_sleep_ns_wakeable(QEMU_CLOCK_REALTIME, ns,
+                                              &call_state->sleep_state);
+                    continue;
+                }
+            }
+
+            ratelimit_calculate_delay(&s->rate_limit, task->bytes);
+        }
+
         trace_block_copy_process(s, task->offset);
 
         co_get_from_shres(s->mem, task->bytes);
@@ -XXX,XX +XXX,XX @@ out:
     return ret < 0 ? ret : found_dirty;
 }
 
+void block_copy_kick(BlockCopyCallState *call_state)
+{
+    if (call_state->sleep_state) {
+        qemu_co_sleep_wake(call_state->sleep_state);
+    }
+}
+
 /*
  * block_copy_common
  *
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
 }
 
 int coroutine_fn block_copy(BlockCopyState *s, int64_t start, int64_t bytes,
-                            bool *error_is_read)
+                            bool ignore_ratelimit, bool *error_is_read)
 {
     BlockCopyCallState call_state = {
         .s = s,
         .offset = start,
         .bytes = bytes,
+        .ignore_ratelimit = ignore_ratelimit,
         .max_workers = BLOCK_COPY_MAX_WORKERS,
     };
 
@@ -XXX,XX +XXX,XX @@ void block_copy_set_skip_unallocated(BlockCopyState *s, bool skip)
 {
     s->skip_unallocated = skip;
 }
+
+void block_copy_set_speed(BlockCopyState *s, uint64_t speed)
+{
+    s->speed = speed;
+    if (speed > 0) {
+        ratelimit_set_speed(&s->rate_limit, speed, BLOCK_COPY_SLICE_TIME);
+    }
+
+    /*
+     * Note: it's good to kick all call states from here, but it should be done
+     * only from a coroutine, to not crash if s->calls list changed while
+     * entering one call. So for now, the only user of this function kicks its
+     * only one call_state by hand.
+     */
+}
-- 
2.29.2

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

Add function to cancel running async block-copy call. It will be used
in backup.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-8-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block-copy.h | 13 +++++++++++++
 block/block-copy.c         | 24 +++++++++++++++++++-----
 2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/include/block/block-copy.h b/include/block/block-copy.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/block-copy.h
+++ b/include/block/block-copy.h
@@ -XXX,XX +XXX,XX @@ void block_copy_call_free(BlockCopyCallState *call_state);
 bool block_copy_call_finished(BlockCopyCallState *call_state);
 bool block_copy_call_succeeded(BlockCopyCallState *call_state);
 bool block_copy_call_failed(BlockCopyCallState *call_state);
+bool block_copy_call_cancelled(BlockCopyCallState *call_state);
 int block_copy_call_status(BlockCopyCallState *call_state, bool *error_is_read);
 
 void block_copy_set_speed(BlockCopyState *s, uint64_t speed);
 void block_copy_kick(BlockCopyCallState *call_state);
 
+/*
+ * Cancel running block-copy call.
+ *
+ * Cancel leaves block-copy state valid: dirty bits are correct and you may use
+ * cancel + <run block_copy with same parameters> to emulate pause/resume.
+ *
+ * Note also, that the cancel is async: it only marks block-copy call to be
+ * cancelled. So, the call may be cancelled (block_copy_call_cancelled() reports
+ * true) but not yet finished (block_copy_call_finished() reports false).
+ */
+void block_copy_call_cancel(BlockCopyCallState *call_state);
+
 BdrvDirtyBitmap *block_copy_dirty_bitmap(BlockCopyState *s);
 void block_copy_set_skip_unallocated(BlockCopyState *s, bool skip);
 
diff --git a/block/block-copy.c b/block/block-copy.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -XXX,XX +XXX,XX @@ typedef struct BlockCopyCallState {
     int ret;
     bool finished;
     QemuCoSleepState *sleep_state;
+    bool cancelled;
 
     /* OUT parameters */
     bool error_is_read;
@@ -XXX,XX +XXX,XX @@ block_copy_dirty_clusters(BlockCopyCallState *call_state)
     assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
     assert(QEMU_IS_ALIGNED(bytes, s->cluster_size));
 
-    while (bytes && aio_task_pool_status(aio) == 0) {
+    while (bytes && aio_task_pool_status(aio) == 0 && !call_state->cancelled) {
         BlockCopyTask *task;
         int64_t status_bytes;
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
     do {
         ret = block_copy_dirty_clusters(call_state);
 
-        if (ret == 0) {
+        if (ret == 0 && !call_state->cancelled) {
             ret = block_copy_wait_one(call_state->s, call_state->offset,
                                       call_state->bytes);
         }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
          * 2. We have waited for some intersecting block-copy request
          *    It may have failed and produced new dirty bits.
          */
-    } while (ret > 0);
+    } while (ret > 0 && !call_state->cancelled);
 
     call_state->finished = true;
 
@@ -XXX,XX +XXX,XX @@ bool block_copy_call_finished(BlockCopyCallState *call_state)
 
 bool block_copy_call_succeeded(BlockCopyCallState *call_state)
 {
-    return call_state->finished && call_state->ret == 0;
+    return call_state->finished && !call_state->cancelled &&
+        call_state->ret == 0;
 }
 
 bool block_copy_call_failed(BlockCopyCallState *call_state)
 {
-    return call_state->finished && call_state->ret < 0;
+    return call_state->finished && !call_state->cancelled &&
+        call_state->ret < 0;
+}
+
+bool block_copy_call_cancelled(BlockCopyCallState *call_state)
+{
+    return call_state->cancelled;
 }
 
 int block_copy_call_status(BlockCopyCallState *call_state, bool *error_is_read)
@@ -XXX,XX +XXX,XX @@ int block_copy_call_status(BlockCopyCallState *call_state, bool *error_is_read)
     return call_state->ret;
 }
 
+void block_copy_call_cancel(BlockCopyCallState *call_state)
+{
+    call_state->cancelled = true;
+    block_copy_kick(call_state);
+}
+
 BdrvDirtyBitmap *block_copy_dirty_bitmap(BlockCopyState *s)
 {
     return s->copy_bitmap;
-- 
2.29.2

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

We are going to use async block-copy call in backup, so we'll need to
passthrough setting backup speed to block-copy call.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-9-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/blockjob_int.h | 2 ++
 blockjob.c                   | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/blockjob_int.h
+++ b/include/block/blockjob_int.h
@@ -XXX,XX +XXX,XX @@ struct BlockJobDriver {
      * besides job->blk to the new AioContext.
      */
     void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
+
+    void (*set_speed)(BlockJob *job, int64_t speed);
 };
 
 /**
diff --git a/blockjob.c b/blockjob.c
index XXXXXXX..XXXXXXX 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -XXX,XX +XXX,XX @@ static bool job_timer_pending(Job *job)
 
 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 {
+    const BlockJobDriver *drv = block_job_driver(job);
     int64_t old_speed = job->speed;
 
     if (job_apply_verb(&job->job, JOB_VERB_SET_SPEED, errp)) {
@@ -XXX,XX +XXX,XX @@ void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
     ratelimit_set_speed(&job->limit, speed, BLOCK_JOB_SLICE_TIME);
 
     job->speed = speed;
+
+    if (drv->set_speed) {
+        drv->set_speed(job, speed);
+    }
+
     if (speed && speed <= old_speed) {
         return;
     }
-- 
2.29.2

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

If main job coroutine called job_yield (while some background process
is in progress), we should give it a chance to call job_pause_point().
It will be used in backup, when moved on async block-copy.

Note, that job_user_pause is not enough: we want to handle
child_job_drained_begin() as well, which call job_pause().

Still, if job is already in job_do_yield() in job_pause_point() we
should not enter it.

iotest 109 output is modified: on stop we do bdrv_drain_all() which now
triggers job pause immediately (and pause after ready is standby).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210116214705.822267-10-vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 job.c                      |  3 +++
 tests/qemu-iotests/109.out | 24 ++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/job.c b/job.c
index XXXXXXX..XXXXXXX 100644
--- a/job.c
+++ b/job.c
@@ -XXX,XX +XXX,XX @@ static bool job_timer_not_pending(Job *job)
 void job_pause(Job *job)
 {
     job->pause_count++;
+    if (!job->paused) {
+        job_enter(job);
+    }
 }
 
 void job_resume(Job *job)
diff --git a/tests/qemu-iotests/109.out b/tests/qemu-iotests/109.out
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/109.out
+++ b/tests/qemu-iotests/109.out
@@ -XXX,XX +XXX,XX @@ read 512/512 bytes at offset 0
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 1024, "offset": 1024, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ read 512/512 bytes at offset 0
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 197120, "offset": 197120, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ read 512/512 bytes at offset 0
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 327680, "offset": 327680, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ read 512/512 bytes at offset 0
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 1024, "offset": 1024, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ read 512/512 bytes at offset 0
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ read 512/512 bytes at offset 0
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2560, "offset": 2560, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ read 512/512 bytes at offset 0
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2560, "offset": 2560, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ read 512/512 bytes at offset 0
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 31457280, "offset": 31457280, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ read 512/512 bytes at offset 0
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 327680, "offset": 327680, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ read 512/512 bytes at offset 0
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2048, "offset": 2048, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ WARNING: Image format was not specified for 'TEST_DIR/t.raw' and probing guessed
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 512, "offset": 512, "speed": 0, "type": "mirror"}}
@@ -XXX,XX +XXX,XX @@ Images are identical.
 {"execute":"quit"}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "standby", "id": "src"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "src"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 512, "offset": 512, "speed": 0, "type": "mirror"}}
-- 
2.29.2

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

Add new parameters to configure future backup features. The patch
doesn't introduce aio backup requests (so we actually have only one
worker) neither requests larger than one cluster. Still, formally we
satisfy these maximums anyway, so add the parameters now, to facilitate
further patch which will really change backup job behavior.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-11-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 qapi/block-core.json | 13 ++++++++++++-
 block/backup.c       | 28 +++++++++++++++++++++++-----
 block/replication.c  |  2 +-
 blockdev.c           |  8 +++++++-
 4 files changed, 43 insertions(+), 8 deletions(-)

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 @@
 #
 # @use-copy-range: Use copy offloading. Default true.
 #
+# @max-workers: Maximum number of parallel requests for the sustained background
+#               copying process. Doesn't influence copy-before-write operations.
+#               Default 64.
+#
+# @max-chunk: Maximum request length for the sustained background copying
+#             process. Doesn't influence copy-before-write operations.
+#             0 means unlimited. If max-chunk is non-zero then it should not be
+#             less than job cluster size which is calculated as maximum of
+#             target image cluster size and 64k. Default 0.
+#
 # Since: 6.0
 ##
 { 'struct': 'BackupPerf',
-  'data': { '*use-copy-range': 'bool' }}
+  'data': { '*use-copy-range': 'bool',
+            '*max-workers': 'int', '*max-chunk': 'int64' } }
 
 ##
 # @BackupCommon:
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;
     }
 
+    cluster_size = backup_calculate_cluster_size(target, errp);
+    if (cluster_size < 0) {
+        goto error;
+    }
+
+    if (perf->max_workers < 1) {
+        error_setg(errp, "max-workers must be greater than zero");
+        return NULL;
+    }
+
+    if (perf->max_chunk < 0) {
+        error_setg(errp, "max-chunk must be zero (which means no limit) or "
+                   "positive");
+        return NULL;
+    }
+
+    if (perf->max_chunk && perf->max_chunk < cluster_size) {
+        error_setg(errp, "Required max-chunk (%" PRIi64 ") is less than backup "
+                   "cluster size (%" PRIi64 ")", perf->max_chunk, cluster_size);
+        return NULL;
+    }
+
+
     if (sync_bitmap) {
         /* If we need to write to this bitmap, check that we can: */
         if (bitmap_mode != BITMAP_SYNC_MODE_NEVER &&
@@ -XXX,XX +XXX,XX @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
         goto error;
     }
 
-    cluster_size = backup_calculate_cluster_size(target, errp);
-    if (cluster_size < 0) {
-        goto error;
-    }
-
     /*
      * If source is in backing chain of target assume that target is going to be
      * used for "image fleecing", i.e. it should represent a kind of snapshot of
diff --git a/block/replication.c b/block/replication.c
index XXXXXXX..XXXXXXX 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -XXX,XX +XXX,XX @@ static void replication_start(ReplicationState *rs, ReplicationMode mode,
     int64_t active_length, hidden_length, disk_length;
     AioContext *aio_context;
     Error *local_err = NULL;
-    BackupPerf perf = { .use_copy_range = true };
+    BackupPerf perf = { .use_copy_range = true, .max_workers = 1 };
 
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
diff --git a/blockdev.c b/blockdev.c
index XXXXXXX..XXXXXXX 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -XXX,XX +XXX,XX @@ static BlockJob *do_backup_common(BackupCommon *backup,
 {
     BlockJob *job = NULL;
     BdrvDirtyBitmap *bmap = NULL;
-    BackupPerf perf = { .use_copy_range = true };
+    BackupPerf perf = { .use_copy_range = true, .max_workers = 64 };
     int job_flags = JOB_DEFAULT;
 
     if (!backup->has_speed) {
@@ -XXX,XX +XXX,XX @@ static BlockJob *do_backup_common(BackupCommon *backup,
         if (backup->x_perf->has_use_copy_range) {
             perf.use_copy_range = backup->x_perf->use_copy_range;
         }
+        if (backup->x_perf->has_max_workers) {
+            perf.max_workers = backup->x_perf->max_workers;
+        }
+        if (backup->x_perf->has_max_chunk) {
+            perf.max_chunk = backup->x_perf->max_chunk;
+        }
     }
 
     if ((backup->sync == MIRROR_SYNC_MODE_BITMAP) ||
-- 
2.29.2

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

After introducing parallel async copy requests instead of plain
cluster-by-cluster copying loop, we'll have to wait for paused status,
as we need to wait for several parallel request. So, let's gently wait
instead of just asserting that job already paused.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-12-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/qemu-iotests/056 | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/tests/qemu-iotests/056 b/tests/qemu-iotests/056
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/056
+++ b/tests/qemu-iotests/056
@@ -XXX,XX +XXX,XX @@ class BackupTest(iotests.QMPTestCase):
         event = self.vm.event_wait(name="BLOCK_JOB_ERROR",
                                    match={'data': {'device': 'drive0'}})
         self.assertNotEqual(event, None)
-        # OK, job should be wedged
-        res = self.vm.qmp('query-block-jobs')
+        # OK, job should pause, but it can't do it immediately, as it can't
+        # cancel other parallel requests (which didn't fail)
+        with iotests.Timeout(60, "Timeout waiting for backup actually paused"):
+            while True:
+                res = self.vm.qmp('query-block-jobs')
+                if res['return'][0]['status'] == 'paused':
+                    break
         self.assert_qmp(res, 'return[0]/status', 'paused')
         res = self.vm.qmp('block-job-dismiss', id='drive0')
         self.assert_qmp(res, 'error/desc',
-- 
2.29.2

Right now, this does not change anything, because backup ignores
max-chunk and max-workers.  However, as soon as backup is switched over
to block-copy for the background copying process, we will need it to
keep 129 passing.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210120102043.28346-1-mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 tests/qemu-iotests/129 | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/129 b/tests/qemu-iotests/129
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/129
+++ b/tests/qemu-iotests/129
@@ -XXX,XX +XXX,XX @@ class TestStopWithBlockJob(iotests.QMPTestCase):
                           sync="full", buf_size=65536)
 
     def test_drive_backup(self):
+        # Limit max-chunk and max-workers so that block-copy will not
+        # launch so many workers working on so much data each that
+        # stop's bdrv_drain_all() would finish the job
         self.do_test_stop("drive-backup", device="drive0",
                           target=self.target_img, format=iotests.imgfmt,
-                          sync="full")
+                          sync="full",
+                          x_perf={ 'max-chunk': 65536,
+                                   'max-workers': 8 })
 
     def test_block_commit(self):
         # Add overlay above the source node so that we actually use a
-- 
2.29.2

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

The further change of moving backup to be a one block-copy call will
make copying chunk-size and cluster-size two separate things. So, even
with 64k cluster sized qcow2 image, default chunk would be 1M.
185 test however assumes, that with speed limited to 64K, one iteration
would result in offset=64K. It will change, as first iteration would
result in offset=1M independently of speed.

So, let's explicitly specify, what test wants: set max-chunk to 64K, so
that one iteration is 64K. Note, that we don't need to limit
max-workers, as block-copy rate limiter will handle the situation and
wouldn't start new workers when speed limit is obviously reached.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-13-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/qemu-iotests/185     | 3 ++-
 tests/qemu-iotests/185.out | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/tests/qemu-iotests/185 b/tests/qemu-iotests/185
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/185
+++ b/tests/qemu-iotests/185
@@ -XXX,XX +XXX,XX @@ _send_qemu_cmd $h \
                       'target': '$TEST_IMG.copy',
                       'format': '$IMGFMT',
                       'sync': 'full',
-                      'speed': 65536 } }" \
+                      'speed': 65536,
+                      'x-perf': {'max-chunk': 65536} } }" \
     "return"
 
 # If we don't sleep here 'quit' command races with disk I/O
diff --git a/tests/qemu-iotests/185.out b/tests/qemu-iotests/185.out
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/185.out
+++ b/tests/qemu-iotests/185.out
@@ -XXX,XX +XXX,XX @@ Formatting 'TEST_DIR/t.qcow2.copy', fmt=qcow2 cluster_size=65536 extended_l2=off
                       'target': 'TEST_DIR/t.IMGFMT.copy',
                       'format': 'IMGFMT',
                       'sync': 'full',
-                      'speed': 65536 } }
+                      'speed': 65536,
+                      'x-perf': { 'max-chunk': 65536 } } }
 Formatting 'TEST_DIR/t.qcow2.copy', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=67108864 lazy_refcounts=off refcount_bits=16
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "created", "id": "disk"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "disk"}}
-- 
2.29.2

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

The further change of moving backup to be a one block-copy call will
make copying chunk-size and cluster-size two separate things. So, even
with 64k cluster sized qcow2 image, default chunk would be 1M.
Test 219 depends on specified chunk-size. Update it for explicit
chunk-size for backup as for mirror.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-14-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/qemu-iotests/219 | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/tests/qemu-iotests/219 b/tests/qemu-iotests/219
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/219
+++ b/tests/qemu-iotests/219
@@ -XXX,XX +XXX,XX @@ with iotests.FilePath('disk.img') as disk_path, \
     # but related to this also automatic state transitions like job
     # completion), but still get pause points often enough to avoid making this
     # test very slow, it's important to have the right ratio between speed and
-    # buf_size.
+    # copy-chunk-size.
     #
-    # For backup, buf_size is hard-coded to the source image cluster size (64k),
-    # so we'll pick the same for mirror. The slice time, i.e. the granularity
-    # of the rate limiting is 100ms. With a speed of 256k per second, we can
-    # get four pause points per second. This gives us 250ms per iteration,
-    # which should be enough to stay deterministic.
+    # Chose 64k copy-chunk-size both for mirror (by buf_size) and backup (by
+    # x-max-chunk). The slice time, i.e. the granularity of the rate limiting
+    # is 100ms. With a speed of 256k per second, we can get four pause points
+    # per second. This gives us 250ms per iteration, which should be enough to
+    # stay deterministic.
 
     test_job_lifecycle(vm, 'drive-mirror', has_ready=True, job_args={
         'device': 'drive0-node',
@@ -XXX,XX +XXX,XX @@ with iotests.FilePath('disk.img') as disk_path, \
                 'target': copy_path,
                 'sync': 'full',
                 'speed': 262144,
+                'x-perf': {'max-chunk': 65536},
                 'auto-finalize': auto_finalize,
                 'auto-dismiss': auto_dismiss,
             })
-- 
2.29.2

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

Iotest 257 dumps a lot of in-progress information of backup job, such
as offset and bitmap dirtiness. Further commit will move backup to be
one block-copy call, which will introduce async parallel requests
instead of plain cluster-by-cluster copying. To keep things
deterministic, allow only one worker (only one copy request at a time)
for this test.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-15-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/qemu-iotests/257     |   1 +
 tests/qemu-iotests/257.out | 306 ++++++++++++++++++-------------------
 2 files changed, 154 insertions(+), 153 deletions(-)

diff --git a/tests/qemu-iotests/257 b/tests/qemu-iotests/257
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/257
+++ b/tests/qemu-iotests/257
@@ -XXX,XX +XXX,XX @@ def blockdev_backup(vm, device, target, sync, **kwargs):
                         target=target,
                         sync=sync,
                         filter_node_name='backup-top',
+                        x_perf={'max-workers': 1},
                         **kwargs)
     return result
 
diff --git a/tests/qemu-iotests/257.out b/tests/qemu-iotests/257.out
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/257.out
+++ b/tests/qemu-iotests/257.out
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 15 dirty sectors; have 15. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 15 dirty sectors; have 15. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"action": "report", "device": "backup_1", "operation": "read"}, "event": "BLOCK_JOB_ERROR", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"device": "backup_1", "error": "Input/output error", "len": 393216, "offset": 65536, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
@@ -XXX,XX +XXX,XX @@ expecting 14 dirty sectors; have 14. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 14 dirty sectors; have 14. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 15 dirty sectors; have 15. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 15 dirty sectors; have 15. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 15 dirty sectors; have 15. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 15 dirty sectors; have 15. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"action": "report", "device": "backup_1", "operation": "read"}, "event": "BLOCK_JOB_ERROR", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"device": "backup_1", "error": "Input/output error", "len": 393216, "offset": 65536, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
@@ -XXX,XX +XXX,XX @@ expecting 14 dirty sectors; have 14. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 14 dirty sectors; have 14. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"action": "report", "device": "backup_1", "operation": "read"}, "event": "BLOCK_JOB_ERROR", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"device": "backup_1", "error": "Input/output error", "len": 393216, "offset": 65536, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
@@ -XXX,XX +XXX,XX @@ expecting 13 dirty sectors; have 13. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 13 dirty sectors; have 13. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "bitmap", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 15 dirty sectors; have 15. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 15 dirty sectors; have 15. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"action": "report", "device": "backup_1", "operation": "read"}, "event": "BLOCK_JOB_ERROR", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"device": "backup_1", "error": "Input/output error", "len": 67108864, "offset": 983040, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
@@ -XXX,XX +XXX,XX @@ expecting 14 dirty sectors; have 14. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 14 dirty sectors; have 14. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"action": "report", "device": "backup_1", "operation": "read"}, "event": "BLOCK_JOB_ERROR", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"device": "backup_1", "error": "Input/output error", "len": 67108864, "offset": 983040, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
@@ -XXX,XX +XXX,XX @@ expecting 1014 dirty sectors; have 1014. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 1014 dirty sectors; have 1014. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "full", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 15 dirty sectors; have 15. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 15 dirty sectors; have 15. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"action": "report", "device": "backup_1", "operation": "read"}, "event": "BLOCK_JOB_ERROR", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"device": "backup_1", "error": "Input/output error", "len": 458752, "offset": 65536, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
@@ -XXX,XX +XXX,XX @@ expecting 14 dirty sectors; have 14. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 14 dirty sectors; have 14. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"action": "report", "device": "backup_1", "operation": "read"}, "event": "BLOCK_JOB_ERROR", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"device": "backup_1", "error": "Input/output error", "len": 458752, "offset": 65536, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
@@ -XXX,XX +XXX,XX @@ expecting 14 dirty sectors; have 14. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 14 dirty sectors; have 14. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ write -P0x76 0x3ff0000 0x10000
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_0", "sync": "full", "target": "ref_target_0", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_1", "sync": "full", "target": "ref_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 6 dirty sectors; have 6. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_1", "sync": "top", "target": "backup_target_1", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 
 --- Write #2 ---
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "ref_backup_2", "sync": "full", "target": "ref_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"data": {"device": "ref_backup_2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 
@@ -XXX,XX +XXX,XX @@ expecting 12 dirty sectors; have 12. OK!
 {"execute": "job-dismiss", "arguments": {"id": "bdc-fmt-job"}}
 {"return": {}}
 {}
-{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2"}}
+{"execute": "blockdev-backup", "arguments": {"auto-finalize": false, "bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "backup_2", "sync": "bitmap", "target": "backup_target_2", "x-perf": {"max-workers": 1}}}
 {"return": {}}
 {"execute": "job-finalize", "arguments": {"id": "backup_2"}}
 {"return": {}}
@@ -XXX,XX +XXX,XX @@ qemu_img compare "TEST_DIR/PID-img" "TEST_DIR/PID-fbackup2" ==> Identical, OK!
 
 -- Sync mode incremental tests --
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "must provide a valid bitmap name for 'incremental' sync mode"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "must provide a valid bitmap name for 'incremental' sync mode"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "must provide a valid bitmap name for 'incremental' sync mode"}}
 
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "must provide a valid bitmap name for 'incremental' sync mode"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap sync mode must be 'on-success' when using sync mode 'incremental'"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap sync mode must be 'on-success' when using sync mode 'incremental'"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap sync mode must be 'on-success' when using sync mode 'incremental'"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "incremental", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap sync mode must be 'on-success' when using sync mode 'incremental'"}}
 
 -- Sync mode bitmap tests --
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "must provide a valid bitmap name for 'bitmap' sync mode"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "must provide a valid bitmap name for 'bitmap' sync mode"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "must provide a valid bitmap name for 'bitmap' sync mode"}}
 
-{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "must provide a valid bitmap name for 'bitmap' sync mode"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "bitmap", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap sync mode must be given when providing a bitmap"}}
 
 -- Sync mode full tests --
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Cannot specify bitmap sync mode without a bitmap"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Cannot specify bitmap sync mode without a bitmap"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Cannot specify bitmap sync mode without a bitmap"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap sync mode 'never' has no meaningful effect when combined with sync mode 'full'"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "full", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap sync mode must be given when providing a bitmap"}}
 
 -- Sync mode top tests --
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Cannot specify bitmap sync mode without a bitmap"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Cannot specify bitmap sync mode without a bitmap"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Cannot specify bitmap sync mode without a bitmap"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap sync mode 'never' has no meaningful effect when combined with sync mode 'top'"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "top", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap sync mode must be given when providing a bitmap"}}
 
 -- Sync mode none tests --
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Cannot specify bitmap sync mode without a bitmap"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Cannot specify bitmap sync mode without a bitmap"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Cannot specify bitmap sync mode without a bitmap"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap404", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap 'bitmap404' could not be found"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "on-success", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "sync mode 'none' does not produce meaningful bitmap outputs"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "always", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "sync mode 'none' does not produce meaningful bitmap outputs"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "bitmap-mode": "never", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "sync mode 'none' does not produce meaningful bitmap outputs"}}
 
-{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target"}}
+{"execute": "blockdev-backup", "arguments": {"bitmap": "bitmap0", "device": "drive0", "filter-node-name": "backup-top", "job-id": "api_job", "sync": "none", "target": "backup_target", "x-perf": {"max-workers": 1}}}
 {"error": {"class": "GenericError", "desc": "Bitmap sync mode must be given when providing a bitmap"}}
 
-- 
2.29.2

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

We are going to stop use of this callback in the following commit.
Still the callback handling code will be dropped in a separate commit.
So, for now let's make it optional.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-16-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/block-copy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/block-copy.c b/block/block-copy.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int block_copy_task_entry(AioTask *task)
         t->call_state->error_is_read = error_is_read;
     } else {
         progress_work_done(t->s->progress, t->bytes);
-        t->s->progress_bytes_callback(t->bytes, t->s->progress_opaque);
+        if (t->s->progress_bytes_callback) {
+            t->s->progress_bytes_callback(t->bytes, t->s->progress_opaque);
+        }
     }
     co_put_to_shres(t->s->mem, t->bytes);
     block_copy_task_end(t, ret);
-- 
2.29.2

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

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-17-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/backup.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

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 @@ static void backup_init_bcs_bitmap(BackupBlockJob *job)
 static int coroutine_fn backup_run(Job *job, Error **errp)
 {
     BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
-    int ret = 0;
+    int ret;
 
     backup_init_bcs_bitmap(s);
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn backup_run(Job *job, Error **errp)
 
         for (offset = 0; offset < s->len; ) {
             if (yield_and_check(s)) {
-                ret = -ECANCELED;
-                goto out;
+                return -ECANCELED;
             }
 
             ret = block_copy_reset_unallocated(s->bcs, offset, &count);
             if (ret < 0) {
-                goto out;
+                return ret;
             }
 
             offset += count;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn backup_run(Job *job, Error **errp)
             job_yield(job);
         }
     } else {
-        ret = backup_loop(s);
+        return backup_loop(s);
     }
 
- out:
-    return ret;
+    return 0;
 }
 
 static const BlockJobDriver backup_job_driver = {
-- 
2.29.2

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

This brings async request handling and block-status driven chunk sizes
to backup out of the box, which improves backup performance.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-18-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/backup.c | 187 +++++++++++++++++++++++++++++++------------------
 1 file changed, 120 insertions(+), 67 deletions(-)

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 @@
 #include "block/block-copy.h"
 #include "qapi/error.h"
 #include "qapi/qmp/qerror.h"
-#include "qemu/ratelimit.h"
 #include "qemu/cutils.h"
 #include "sysemu/block-backend.h"
 #include "qemu/bitmap.h"
@@ -XXX,XX +XXX,XX @@ typedef struct BackupBlockJob {
     BlockdevOnError on_source_error;
     BlockdevOnError on_target_error;
     uint64_t len;
-    uint64_t bytes_read;
     int64_t cluster_size;
     BackupPerf perf;
 
     BlockCopyState *bcs;
+
+    bool wait;
+    BlockCopyCallState *bg_bcs_call;
 } BackupBlockJob;
 
 static const BlockJobDriver backup_job_driver;
 
-static void backup_progress_bytes_callback(int64_t bytes, void *opaque)
-{
-    BackupBlockJob *s = opaque;
-
-    s->bytes_read += bytes;
-}
-
-static int coroutine_fn backup_do_cow(BackupBlockJob *job,
-                                      int64_t offset, uint64_t bytes,
-                                      bool *error_is_read)
-{
-    int ret = 0;
-    int64_t start, end; /* bytes */
-
-    start = QEMU_ALIGN_DOWN(offset, job->cluster_size);
-    end = QEMU_ALIGN_UP(bytes + offset, job->cluster_size);
-
-    trace_backup_do_cow_enter(job, start, offset, bytes);
-
-    ret = block_copy(job->bcs, start, end - start, true, error_is_read);
-
-    trace_backup_do_cow_return(job, offset, bytes, ret);
-
-    return ret;
-}
-
 static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
 {
     BdrvDirtyBitmap *bm;
@@ -XXX,XX +XXX,XX @@ static BlockErrorAction backup_error_action(BackupBlockJob *job,
     }
 }
 
-static bool coroutine_fn yield_and_check(BackupBlockJob *job)
+static void coroutine_fn backup_block_copy_callback(void *opaque)
 {
-    uint64_t delay_ns;
-
-    if (job_is_cancelled(&job->common.job)) {
-        return true;
-    }
-
-    /*
-     * We need to yield even for delay_ns = 0 so that bdrv_drain_all() can
-     * return. Without a yield, the VM would not reboot.
-     */
-    delay_ns = block_job_ratelimit_get_delay(&job->common, job->bytes_read);
-    job->bytes_read = 0;
-    job_sleep_ns(&job->common.job, delay_ns);
+    BackupBlockJob *s = opaque;
 
-    if (job_is_cancelled(&job->common.job)) {
-        return true;
+    if (s->wait) {
+        s->wait = false;
+        aio_co_wake(s->common.job.co);
+    } else {
+        job_enter(&s->common.job);
     }
-
-    return false;
 }
 
 static int coroutine_fn backup_loop(BackupBlockJob *job)
 {
-    bool error_is_read;
-    int64_t offset;
-    BdrvDirtyBitmapIter *bdbi;
+    BlockCopyCallState *s = NULL;
     int ret = 0;
+    bool error_is_read;
+    BlockErrorAction act;
+
+    while (true) { /* retry loop */
+        job->bg_bcs_call = s = block_copy_async(job->bcs, 0,
+                QEMU_ALIGN_UP(job->len, job->cluster_size),
+                job->perf.max_workers, job->perf.max_chunk,
+                backup_block_copy_callback, job);
+
+        while (!block_copy_call_finished(s) &&
+               !job_is_cancelled(&job->common.job))
+        {
+            job_yield(&job->common.job);
+        }
 
-    bdbi = bdrv_dirty_iter_new(block_copy_dirty_bitmap(job->bcs));
-    while ((offset = bdrv_dirty_iter_next(bdbi)) != -1) {
-        do {
-            if (yield_and_check(job)) {
-                goto out;
-            }
-            ret = backup_do_cow(job, offset, job->cluster_size, &error_is_read);
-            if (ret < 0 && backup_error_action(job, error_is_read, -ret) ==
-                           BLOCK_ERROR_ACTION_REPORT)
-            {
-                goto out;
-            }
-        } while (ret < 0);
+        if (!block_copy_call_finished(s)) {
+            assert(job_is_cancelled(&job->common.job));
+            /*
+             * Note that we can't use job_yield() here, as it doesn't work for
+             * cancelled job.
+             */
+            block_copy_call_cancel(s);
+            job->wait = true;
+            qemu_coroutine_yield();
+            assert(block_copy_call_finished(s));
+            ret = 0;
+            goto out;
+        }
+
+        if (job_is_cancelled(&job->common.job) ||
+            block_copy_call_succeeded(s))
+        {
+            ret = 0;
+            goto out;
+        }
+
+        if (block_copy_call_cancelled(s)) {
+            /*
+             * Job is not cancelled but only block-copy call. This is possible
+             * after job pause. Now the pause is finished, start new block-copy
+             * iteration.
+             */
+            block_copy_call_free(s);
+            continue;
+        }
+
+        /* The only remaining case is failed block-copy call. */
+        assert(block_copy_call_failed(s));
+
+        ret = block_copy_call_status(s, &error_is_read);
+        act = backup_error_action(job, error_is_read, -ret);
+        switch (act) {
+        case BLOCK_ERROR_ACTION_REPORT:
+            goto out;
+        case BLOCK_ERROR_ACTION_STOP:
+            /*
+             * Go to pause prior to starting new block-copy call on the next
+             * iteration.
+             */
+            job_pause_point(&job->common.job);
+            break;
+        case BLOCK_ERROR_ACTION_IGNORE:
+            /* Proceed to new block-copy call to retry. */
+            break;
+        default:
+            abort();
+        }
+
+        block_copy_call_free(s);
     }
 
- out:
-    bdrv_dirty_iter_free(bdbi);
+out:
+    block_copy_call_free(s);
+    job->bg_bcs_call = NULL;
     return ret;
 }
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn backup_run(Job *job, Error **errp)
         int64_t count;
 
         for (offset = 0; offset < s->len; ) {
-            if (yield_and_check(s)) {
+            if (job_is_cancelled(job)) {
+                return -ECANCELED;
+            }
+
+            job_pause_point(job);
+
+            if (job_is_cancelled(job)) {
                 return -ECANCELED;
             }
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn backup_run(Job *job, Error **errp)
     return 0;
 }
 
+static void coroutine_fn backup_pause(Job *job)
+{
+    BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
+
+    if (s->bg_bcs_call && !block_copy_call_finished(s->bg_bcs_call)) {
+        block_copy_call_cancel(s->bg_bcs_call);
+        s->wait = true;
+        qemu_coroutine_yield();
+    }
+}
+
+static void coroutine_fn backup_set_speed(BlockJob *job, int64_t speed)
+{
+    BackupBlockJob *s = container_of(job, BackupBlockJob, common);
+
+    /*
+     * block_job_set_speed() is called first from block_job_create(), when we
+     * don't yet have s->bcs.
+     */
+    if (s->bcs) {
+        block_copy_set_speed(s->bcs, speed);
+        if (s->bg_bcs_call) {
+            block_copy_kick(s->bg_bcs_call);
+        }
+    }
+}
+
 static const BlockJobDriver backup_job_driver = {
     .job_driver = {
         .instance_size          = sizeof(BackupBlockJob),
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver backup_job_driver = {
         .commit                 = backup_commit,
         .abort                  = backup_abort,
         .clean                  = backup_clean,
-    }
+        .pause                  = backup_pause,
+    },
+    .set_speed = backup_set_speed,
 };
 
 static int64_t backup_calculate_cluster_size(BlockDriverState *target,
@@ -XXX,XX +XXX,XX @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
     job->len = len;
     job->perf = *perf;
 
-    block_copy_set_progress_callback(bcs, backup_progress_bytes_callback, job);
     block_copy_set_progress_meter(bcs, &job->common.job.progress);
+    block_copy_set_speed(bcs, speed);
 
     /* Required permissions are already taken by backup-top target */
     block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
-- 
2.29.2

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

Further commit will add a benchmark
(scripts/simplebench/bench-backup.py), which will show that backup
works better with async parallel requests (previous commit) and
disabled copy_range. So, let's disable copy_range by default.

Note: the option was added several commits ago with default to true,
to follow old behavior (the feature was enabled unconditionally), and
only now we are going to change the default behavior.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-19-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 qapi/block-core.json | 2 +-
 blockdev.c           | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

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 @@
 # Optional parameters for backup. These parameters don't affect
 # functionality, but may significantly affect performance.
 #
-# @use-copy-range: Use copy offloading. Default true.
+# @use-copy-range: Use copy offloading. Default false.
 #
 # @max-workers: Maximum number of parallel requests for the sustained background
 #               copying process. Doesn't influence copy-before-write operations.
diff --git a/blockdev.c b/blockdev.c
index XXXXXXX..XXXXXXX 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -XXX,XX +XXX,XX @@ static BlockJob *do_backup_common(BackupCommon *backup,
 {
     BlockJob *job = NULL;
     BdrvDirtyBitmap *bmap = NULL;
-    BackupPerf perf = { .use_copy_range = true, .max_workers = 64 };
+    BackupPerf perf = { .max_workers = 64 };
     int job_flags = JOB_DEFAULT;
 
     if (!backup->has_speed) {
-- 
2.29.2

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

Drop unused code.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-20-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block-copy.h |  6 ------
 block/block-copy.c         | 15 ---------------
 2 files changed, 21 deletions(-)

diff --git a/include/block/block-copy.h b/include/block/block-copy.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/block-copy.h
+++ b/include/block/block-copy.h
@@ -XXX,XX +XXX,XX @@
 #include "block/block.h"
 #include "qemu/co-shared-resource.h"
 
-typedef void (*ProgressBytesCallbackFunc)(int64_t bytes, void *opaque);
 typedef void (*BlockCopyAsyncCallbackFunc)(void *opaque);
 typedef struct BlockCopyState BlockCopyState;
 typedef struct BlockCopyCallState BlockCopyCallState;
@@ -XXX,XX +XXX,XX @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
                                      BdrvRequestFlags write_flags,
                                      Error **errp);
 
-void block_copy_set_progress_callback(
-        BlockCopyState *s,
-        ProgressBytesCallbackFunc progress_bytes_callback,
-        void *progress_opaque);
-
 void block_copy_set_progress_meter(BlockCopyState *s, ProgressMeter *pm);
 
 void block_copy_state_free(BlockCopyState *s);
diff --git a/block/block-copy.c b/block/block-copy.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -XXX,XX +XXX,XX @@ typedef struct BlockCopyState {
     bool skip_unallocated;
 
     ProgressMeter *progress;
-    /* progress_bytes_callback: called when some copying progress is done. */
-    ProgressBytesCallbackFunc progress_bytes_callback;
-    void *progress_opaque;
 
     SharedResource *mem;
 
@@ -XXX,XX +XXX,XX @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
     return s;
 }
 
-void block_copy_set_progress_callback(
-        BlockCopyState *s,
-        ProgressBytesCallbackFunc progress_bytes_callback,
-        void *progress_opaque)
-{
-    s->progress_bytes_callback = progress_bytes_callback;
-    s->progress_opaque = progress_opaque;
-}
-
 void block_copy_set_progress_meter(BlockCopyState *s, ProgressMeter *pm)
 {
     s->progress = pm;
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int block_copy_task_entry(AioTask *task)
         t->call_state->error_is_read = error_is_read;
     } else {
         progress_work_done(t->s->progress, t->bytes);
-        if (t->s->progress_bytes_callback) {
-            t->s->progress_bytes_callback(t->bytes, t->s->progress_opaque);
-        }
     }
     co_put_to_shres(t->s->mem, t->bytes);
     block_copy_task_end(t, ret);
-- 
2.29.2

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

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-21-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block-copy.h |  2 +-
 block/backup-top.c         |  2 +-
 block/block-copy.c         | 10 ++--------
 3 files changed, 4 insertions(+), 10 deletions(-)

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

Add argument to allow additional block-job options.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-23-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 scripts/simplebench/bench-example.py   |  2 +-
 scripts/simplebench/bench_block_job.py | 11 +++++++----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/scripts/simplebench/bench-example.py b/scripts/simplebench/bench-example.py
index XXXXXXX..XXXXXXX 100644
--- a/scripts/simplebench/bench-example.py
+++ b/scripts/simplebench/bench-example.py
@@ -XXX,XX +XXX,XX @@ from bench_block_job import bench_block_copy, drv_file, drv_nbd
 
 def bench_func(env, case):
     """ Handle one "cell" of benchmarking table. """
-    return bench_block_copy(env['qemu_binary'], env['cmd'],
+    return bench_block_copy(env['qemu_binary'], env['cmd'], {}
                             case['source'], case['target'])
 
 
diff --git a/scripts/simplebench/bench_block_job.py b/scripts/simplebench/bench_block_job.py
index XXXXXXX..XXXXXXX 100755
--- a/scripts/simplebench/bench_block_job.py
+++ b/scripts/simplebench/bench_block_job.py
@@ -XXX,XX +XXX,XX @@ def bench_block_job(cmd, cmd_args, qemu_args):
 
 
 # Bench backup or mirror
-def bench_block_copy(qemu_binary, cmd, source, target):
+def bench_block_copy(qemu_binary, cmd, cmd_options, source, target):
     """Helper to run bench_block_job() for mirror or backup"""
     assert cmd in ('blockdev-backup', 'blockdev-mirror')
 
     source['node-name'] = 'source'
     target['node-name'] = 'target'
 
-    return bench_block_job(cmd,
-                           {'job-id': 'job0', 'device': 'source',
-                            'target': 'target', 'sync': 'full'},
+    cmd_options['job-id'] = 'job0'
+    cmd_options['device'] = 'source'
+    cmd_options['target'] = 'target'
+    cmd_options['sync'] = 'full'
+
+    return bench_block_job(cmd, cmd_options,
                            [qemu_binary,
                             '-blockdev', json.dumps(source),
                             '-blockdev', json.dumps(target)])
-- 
2.29.2

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

Add script to benchmark new backup architecture.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210116214705.822267-24-vsementsov@virtuozzo.com>
[mreitz: s/not unsupported/not supported/]
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 scripts/simplebench/bench-backup.py | 167 ++++++++++++++++++++++++++++
 1 file changed, 167 insertions(+)
 create mode 100755 scripts/simplebench/bench-backup.py

diff --git a/scripts/simplebench/bench-backup.py b/scripts/simplebench/bench-backup.py
new file mode 100755
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/scripts/simplebench/bench-backup.py
@@ -XXX,XX +XXX,XX @@
+#!/usr/bin/env python3
+#
+# Bench backup block-job
+#
+# Copyright (c) 2020 Virtuozzo International GmbH.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import argparse
+import json
+
+import simplebench
+from results_to_text import results_to_text
+from bench_block_job import bench_block_copy, drv_file, drv_nbd
+
+
+def bench_func(env, case):
+    """ Handle one "cell" of benchmarking table. """
+    cmd_options = env['cmd-options'] if 'cmd-options' in env else {}
+    return bench_block_copy(env['qemu-binary'], env['cmd'],
+                            cmd_options,
+                            case['source'], case['target'])
+
+
+def bench(args):
+    test_cases = []
+
+    sources = {}
+    targets = {}
+    for d in args.dir:
+        label, path = d.split(':')  # paths with colon not supported
+        sources[label] = drv_file(path + '/test-source')
+        targets[label] = drv_file(path + '/test-target')
+
+    if args.nbd:
+        nbd = args.nbd.split(':')
+        host = nbd[0]
+        port = '10809' if len(nbd) == 1 else nbd[1]
+        drv = drv_nbd(host, port)
+        sources['nbd'] = drv
+        targets['nbd'] = drv
+
+    for t in args.test:
+        src, dst = t.split(':')
+
+        test_cases.append({
+            'id': t,
+            'source': sources[src],
+            'target': targets[dst]
+        })
+
+    binaries = []  # list of (<label>, <path>, [<options>])
+    for i, q in enumerate(args.env):
+        name_path = q.split(':')
+        if len(name_path) == 1:
+            label = f'q{i}'
+            path_opts = name_path[0].split(',')
+        else:
+            assert len(name_path) == 2  # paths with colon not supported
+            label = name_path[0]
+            path_opts = name_path[1].split(',')
+
+        binaries.append((label, path_opts[0], path_opts[1:]))
+
+    test_envs = []
+
+    bin_paths = {}
+    for i, q in enumerate(args.env):
+        opts = q.split(',')
+        label_path = opts[0]
+        opts = opts[1:]
+
+        if ':' in label_path:
+            # path with colon inside is not supported
+            label, path = label_path.split(':')
+            bin_paths[label] = path
+        elif label_path in bin_paths:
+            label = label_path
+            path = bin_paths[label]
+        else:
+            path = label_path
+            label = f'q{i}'
+            bin_paths[label] = path
+
+        x_perf = {}
+        is_mirror = False
+        for opt in opts:
+            if opt == 'mirror':
+                is_mirror = True
+            elif opt == 'copy-range=on':
+                x_perf['use-copy-range'] = True
+            elif opt == 'copy-range=off':
+                x_perf['use-copy-range'] = False
+            elif opt.startswith('max-workers='):
+                x_perf['max-workers'] = int(opt.split('=')[1])
+
+        if is_mirror:
+            assert not x_perf
+            test_envs.append({
+                    'id': f'mirror({label})',
+                    'cmd': 'blockdev-mirror',
+                    'qemu-binary': path
+                })
+        else:
+            test_envs.append({
+                'id': f'backup({label})\n' + '\n'.join(opts),
+                'cmd': 'blockdev-backup',
+                'cmd-options': {'x-perf': x_perf} if x_perf else {},
+                'qemu-binary': path
+            })
+
+    result = simplebench.bench(bench_func, test_envs, test_cases, count=3)
+    with open('results.json', 'w') as f:
+        json.dump(result, f, indent=4)
+    print(results_to_text(result))
+
+
+class ExtendAction(argparse.Action):
+    def __call__(self, parser, namespace, values, option_string=None):
+        items = getattr(namespace, self.dest) or []
+        items.extend(values)
+        setattr(namespace, self.dest, items)
+
+
+if __name__ == '__main__':
+    p = argparse.ArgumentParser('Backup benchmark', epilog='''
+ENV format
+
+    (LABEL:PATH|LABEL|PATH)[,max-workers=N][,use-copy-range=(on|off)][,mirror]
+
+    LABEL                short name for the binary
+    PATH                 path to the binary
+    max-workers          set x-perf.max-workers of backup job
+    use-copy-range       set x-perf.use-copy-range of backup job
+    mirror               use mirror job instead of backup''',
+                                formatter_class=argparse.RawTextHelpFormatter)
+    p.add_argument('--env', nargs='+', help='''\
+Qemu binaries with labels and options, see below
+"ENV format" section''',
+                   action=ExtendAction)
+    p.add_argument('--dir', nargs='+', help='''\
+Directories, each containing "test-source" and/or
+"test-target" files, raw images to used in
+benchmarking. File path with label, like
+label:/path/to/directory''',
+                   action=ExtendAction)
+    p.add_argument('--nbd', help='''\
+host:port for remote NBD image, (or just host, for
+default port 10809). Use it in tests, label is "nbd"
+(but you cannot create test nbd:nbd).''')
+    p.add_argument('--test', nargs='+', help='''\
+Tests, in form source-dir-label:target-dir-label''',
+                   action=ExtendAction)
+
+    bench(p.parse_args())
-- 
2.29.2

From: David Edmondson <david.edmondson@oracle.com>

When a call to fcntl(2) for the purpose of adding file locks fails
with an error other than EAGAIN or EACCES, report the error returned
by fcntl.

EAGAIN or EACCES are elided as they are considered to be common
failures, indicating that a conflicting lock is held by another
process.

No errors are elided when removing file locks.

Signed-off-by: David Edmondson <david.edmondson@oracle.com>
Message-Id: <20210113164447.2545785-1-david.edmondson@oracle.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/file-posix.c | 38 ++++++++++++++++++++++++++++----------
 1 file changed, 28 insertions(+), 10 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index XXXXXXX..XXXXXXX 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -XXX,XX +XXX,XX @@ typedef struct RawPosixAIOData {
 static int cdrom_reopen(BlockDriverState *bs);
 #endif
 
+/*
+ * Elide EAGAIN and EACCES details when failing to lock, as this
+ * indicates that the specified file region is already locked by
+ * another process, which is considered a common scenario.
+ */
+#define raw_lock_error_setg_errno(errp, err, fmt, ...)                  \
+    do {                                                                \
+        if ((err) == EAGAIN || (err) == EACCES) {                       \
+            error_setg((errp), (fmt), ## __VA_ARGS__);                  \
+        } else {                                                        \
+            error_setg_errno((errp), (err), (fmt), ## __VA_ARGS__);     \
+        }                                                               \
+    } while (0)
+
 #if defined(__NetBSD__)
 static int raw_normalize_devicepath(const char **filename, Error **errp)
 {
@@ -XXX,XX +XXX,XX @@ static int raw_apply_lock_bytes(BDRVRawState *s, int fd,
         if ((perm_lock_bits & bit) && !(locked_perm & bit)) {
             ret = qemu_lock_fd(fd, off, 1, false);
             if (ret) {
-                error_setg(errp, "Failed to lock byte %d", off);
+                raw_lock_error_setg_errno(errp, -ret, "Failed to lock byte %d",
+                                          off);
                 return ret;
             } else if (s) {
                 s->locked_perm |= bit;
@@ -XXX,XX +XXX,XX @@ static int raw_apply_lock_bytes(BDRVRawState *s, int fd,
         } else if (unlock && (locked_perm & bit) && !(perm_lock_bits & bit)) {
             ret = qemu_unlock_fd(fd, off, 1);
             if (ret) {
-                error_setg(errp, "Failed to unlock byte %d", off);
+                error_setg_errno(errp, -ret, "Failed to unlock byte %d", off);
                 return ret;
             } else if (s) {
                 s->locked_perm &= ~bit;
@@ -XXX,XX +XXX,XX @@ static int raw_apply_lock_bytes(BDRVRawState *s, int fd,
         if ((shared_perm_lock_bits & bit) && !(locked_shared_perm & bit)) {
             ret = qemu_lock_fd(fd, off, 1, false);
             if (ret) {
-                error_setg(errp, "Failed to lock byte %d", off);
+                raw_lock_error_setg_errno(errp, -ret, "Failed to lock byte %d",
+                                          off);
                 return ret;
             } else if (s) {
                 s->locked_shared_perm |= bit;
@@ -XXX,XX +XXX,XX @@ static int raw_apply_lock_bytes(BDRVRawState *s, int fd,
                    !(shared_perm_lock_bits & bit)) {
             ret = qemu_unlock_fd(fd, off, 1);
             if (ret) {
-                error_setg(errp, "Failed to unlock byte %d", off);
+                error_setg_errno(errp, -ret, "Failed to unlock byte %d", off);
                 return ret;
             } else if (s) {
                 s->locked_shared_perm &= ~bit;
@@ -XXX,XX +XXX,XX @@ static int raw_check_lock_bytes(int fd, uint64_t perm, uint64_t shared_perm,
             ret = qemu_lock_fd_test(fd, off, 1, true);
             if (ret) {
                 char *perm_name = bdrv_perm_names(p);
-                error_setg(errp,
-                           "Failed to get \"%s\" lock",
-                           perm_name);
+
+                raw_lock_error_setg_errno(errp, -ret,
+                                          "Failed to get \"%s\" lock",
+                                          perm_name);
                 g_free(perm_name);
                 return ret;
             }
@@ -XXX,XX +XXX,XX @@ static int raw_check_lock_bytes(int fd, uint64_t perm, uint64_t shared_perm,
             ret = qemu_lock_fd_test(fd, off, 1, true);
             if (ret) {
                 char *perm_name = bdrv_perm_names(p);
-                error_setg(errp,
-                           "Failed to get shared \"%s\" lock",
-                           perm_name);
+
+                raw_lock_error_setg_errno(errp, -ret,
+                                          "Failed to get shared \"%s\" lock",
+                                          perm_name);
                 g_free(perm_name);
                 return ret;
             }
-- 
2.29.2

From: Alberto Garcia <berto@igalia.com>

Signed-off-by: Alberto Garcia <berto@igalia.com>
Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210112170540.2912-1-berto@igalia.com>
[mreitz: Add "# group:" line]
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/qemu-iotests/313     | 104 +++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/313.out |  29 +++++++++++
 tests/qemu-iotests/group   |   1 +
 3 files changed, 134 insertions(+)
 create mode 100755 tests/qemu-iotests/313
 create mode 100644 tests/qemu-iotests/313.out

diff --git a/tests/qemu-iotests/313 b/tests/qemu-iotests/313
new file mode 100755
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/tests/qemu-iotests/313
@@ -XXX,XX +XXX,XX @@
+#!/usr/bin/env bash
+# group: rw auto quick
+#
+# Test for the regression fixed in commit c8bf9a9169
+#
+# Copyright (C) 2020 Igalia, S.L.
+# Author: Alberto Garcia <berto@igalia.com>
+# Based on a test case by Maxim Levitsky <mlevitsk@redhat.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=berto@igalia.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+status=1    # failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+_unsupported_imgopts cluster_size refcount_bits extended_l2 compat=0.10 data_file
+
+# The cluster size must be at least the granularity of the mirror job (4KB)
+# Note that larger cluster sizes will produce very large images (several GBs)
+cluster_size=4096
+refcount_bits=64 # Make it equal to the L2 entry size for convenience
+options="cluster_size=${cluster_size},refcount_bits=${refcount_bits}"
+
+# Number of refcount entries per refcount blocks
+ref_entries=$(( ${cluster_size} * 8 / ${refcount_bits} ))
+
+# Number of data clusters needed to fill a refcount block
+# Equals ${ref_entries} minus two (one L2 table and one refcount block)
+data_clusters_per_refblock=$(( ${ref_entries} - 2 ))
+
+# Number of entries in the refcount cache
+ref_blocks=4
+
+# Write enough data clusters to fill the refcount cache and allocate
+# one more refcount block.
+# Subtract 3 clusters from the total: qcow2 header, refcount table, L1 table
+total_data_clusters=$(( ${data_clusters_per_refblock} * ${ref_blocks} + 1 - 3 ))
+
+# Total size to write in bytes
+total_size=$(( ${total_data_clusters} * ${cluster_size} ))
+
+echo
+echo '### Create the image'
+echo
+TEST_IMG_FILE=$TEST_IMG.base _make_test_img -o $options $total_size | _filter_img_create_size
+
+echo
+echo '### Write data to allocate more refcount blocks than the cache can hold'
+echo
+$QEMU_IO -c "write -P 1 0 $total_size" $TEST_IMG.base | _filter_qemu_io
+
+echo
+echo '### Create an overlay'
+echo
+_make_test_img -F $IMGFMT -b $TEST_IMG.base -o $options | _filter_img_create_size
+
+echo
+echo '### Fill the overlay with zeroes'
+echo
+$QEMU_IO -c "write -z 0 $total_size" $TEST_IMG | _filter_qemu_io
+
+echo
+echo '### Commit changes to the base image'
+echo
+$QEMU_IMG commit $TEST_IMG
+
+echo
+echo '### Check the base image'
+echo
+$QEMU_IMG check $TEST_IMG.base
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/313.out b/tests/qemu-iotests/313.out
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/tests/qemu-iotests/313.out
@@ -XXX,XX +XXX,XX @@
+QA output created by 313
+
+### Create the image
+
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=SIZE
+
+### Write data to allocate more refcount blocks than the cache can hold
+
+wrote 8347648/8347648 bytes at offset 0
+7.961 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+### Create an overlay
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=SIZE backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
+
+### Fill the overlay with zeroes
+
+wrote 8347648/8347648 bytes at offset 0
+7.961 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+### Commit changes to the base image
+
+Image committed.
+
+### Check the base image
+
+No errors were found on the image.
+Image end offset: 8396800
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -XXX,XX +XXX,XX @@
 309 rw auto quick
 310 rw quick
 312 rw quick
+313 rw auto quick
-- 
2.29.2

Commit 0afec75734331 removed the 'change' QMP command, so we can no
longer test it in 118.

Fixes: 0afec75734331a0b52fa3aa4235220eda8c7846f
       ('qmp: remove deprecated "change" command')
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210126104833.57026-1-mreitz@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 tests/qemu-iotests/118     | 20 +-------------------
 tests/qemu-iotests/118.out |  4 ++--
 2 files changed, 3 insertions(+), 21 deletions(-)

diff --git a/tests/qemu-iotests/118 b/tests/qemu-iotests/118
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/118
+++ b/tests/qemu-iotests/118
@@ -XXX,XX +XXX,XX @@
 #!/usr/bin/env python3
 # group: rw
 #
-# Test case for the QMP 'change' command and all other associated
-# commands
+# Test case for media change monitor commands
 #
 # Copyright (C) 2015 Red Hat, Inc.
 #
@@ -XXX,XX +XXX,XX @@ class ChangeBaseClass(iotests.QMPTestCase):
 
 class GeneralChangeTestsBaseClass(ChangeBaseClass):
 
-    def test_change(self):
-        # 'change' requires a drive name, so skip the test for blockdev
-        if not self.use_drive:
-            return
-
-        result = self.vm.qmp('change', device='drive0', target=new_img,
-                                       arg=iotests.imgfmt)
-        self.assert_qmp(result, 'return', {})
-
-        self.wait_for_open()
-        self.wait_for_close()
-
-        result = self.vm.qmp('query-block')
-        if self.has_real_tray:
-            self.assert_qmp(result, 'return[0]/tray_open', False)
-        self.assert_qmp(result, 'return[0]/inserted/image/filename', new_img)
-
     def test_blockdev_change_medium(self):
         result = self.vm.qmp('blockdev-change-medium',
                              id=self.device_name, filename=new_img,
diff --git a/tests/qemu-iotests/118.out b/tests/qemu-iotests/118.out
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/118.out
+++ b/tests/qemu-iotests/118.out
@@ -XXX,XX +XXX,XX @@
-.......................................................................................................................................................................
+...........................................................................................................................................................
 ----------------------------------------------------------------------
-Ran 167 tests
+Ran 155 tests
 
 OK
-- 
2.29.2

ccd3b3b8112 has deprecated short-hand boolean options (i.e., options
with values).  All options without values are interpreted as boolean
options, so this includes the invalid option "snapshot.foo" used in
iotest 178.

So after ccd3b3b8112, 178 fails with:

+qemu-img: warning: short-form boolean option 'snapshot.foo' deprecated
  +Please use snapshot.foo=on instead

Suppress that deprecation warning by passing some value to it (it does
not matter which, because the option is invalid anyway).

Fixes: ccd3b3b8112b670fdccf8a392b8419b173ffccb4
       ("qemu-option: warn for short-form boolean options")
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210126123834.115915-1-mreitz@redhat.com>
---
 tests/qemu-iotests/178           | 2 +-
 tests/qemu-iotests/178.out.qcow2 | 2 +-
 tests/qemu-iotests/178.out.raw   | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/qemu-iotests/178 b/tests/qemu-iotests/178
index XXXXXXX..XXXXXXX 100755
--- a/tests/qemu-iotests/178
+++ b/tests/qemu-iotests/178
@@ -XXX,XX +XXX,XX @@ $QEMU_IMG measure --image-opts # missing filename
 $QEMU_IMG measure -f qcow2 # missing filename
 $QEMU_IMG measure -l snap1 # missing filename
 $QEMU_IMG measure -o , # invalid option list
-$QEMU_IMG measure -l snapshot.foo # invalid snapshot option
+$QEMU_IMG measure -l snapshot.foo=bar # invalid snapshot option
 $QEMU_IMG measure --output foo # invalid output format
 $QEMU_IMG measure --size -1 # invalid image size
 $QEMU_IMG measure -O foo "$TEST_IMG" # unknown image file format
diff --git a/tests/qemu-iotests/178.out.qcow2 b/tests/qemu-iotests/178.out.qcow2
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/178.out.qcow2
+++ b/tests/qemu-iotests/178.out.qcow2
@@ -XXX,XX +XXX,XX @@ qemu-img: --image-opts, -f, and -l require a filename argument.
 qemu-img: --image-opts, -f, and -l require a filename argument.
 qemu-img: Invalid option list: ,
 qemu-img: Invalid parameter 'snapshot.foo'
-qemu-img: Failed in parsing snapshot param 'snapshot.foo'
+qemu-img: Failed in parsing snapshot param 'snapshot.foo=bar'
 qemu-img: --output must be used with human or json as argument.
 qemu-img: Invalid image size specified. Must be between 0 and 9223372036854775807.
 qemu-img: Unknown file format 'foo'
diff --git a/tests/qemu-iotests/178.out.raw b/tests/qemu-iotests/178.out.raw
index XXXXXXX..XXXXXXX 100644
--- a/tests/qemu-iotests/178.out.raw
+++ b/tests/qemu-iotests/178.out.raw
@@ -XXX,XX +XXX,XX @@ qemu-img: --image-opts, -f, and -l require a filename argument.
 qemu-img: --image-opts, -f, and -l require a filename argument.
 qemu-img: Invalid option list: ,
 qemu-img: Invalid parameter 'snapshot.foo'
-qemu-img: Failed in parsing snapshot param 'snapshot.foo'
+qemu-img: Failed in parsing snapshot param 'snapshot.foo=bar'
 qemu-img: --output must be used with human or json as argument.
 qemu-img: Invalid image size specified. Must be between 0 and 9223372036854775807.
 qemu-img: Unknown file format 'foo'
-- 
2.29.2

The following changes since commit 1214d55d1c41fbab3a9973a05085b8760647e411:

Merge remote-tracking branch 'remotes/nvme/tags/nvme-next-pull-request' into staging (2021-02-09 13:24:37 +0000)

are available in the Git repository at:

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

for you to fetch changes up to eb847c42296497978942f738cd41dc29a35a49b2:

docs: fix Parallels Image "dirty bitmap" section (2021-02-10 09:23:28 +0000)

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

v4:
 * Add PCI_EXPRESS Kconfig dependency to fix s390x in "multi-process: setup PCI
   host bridge for remote device" [Philippe and Thomas]

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

Denis V. Lunev (1):
  docs: fix Parallels Image "dirty bitmap" section

Elena Ufimtseva (8):
  multi-process: add configure and usage information
  io: add qio_channel_writev_full_all helper
  io: add qio_channel_readv_full_all_eof & qio_channel_readv_full_all
    helpers
  multi-process: define MPQemuMsg format and transmission functions
  multi-process: introduce proxy object
  multi-process: add proxy communication functions
  multi-process: Forward PCI config space acceses to the remote process
  multi-process: perform device reset in the remote process

Jagannathan Raman (11):
  memory: alloc RAM from file at offset
  multi-process: Add config option for multi-process QEMU
  multi-process: setup PCI host bridge for remote device
  multi-process: setup a machine object for remote device process
  multi-process: Initialize message handler in remote device
  multi-process: Associate fd of a PCIDevice with its object
  multi-process: setup memory manager for remote device
  multi-process: PCI BAR read/write handling for proxy & remote
    endpoints
  multi-process: Synchronize remote memory
  multi-process: create IOHUB object to handle irq
  multi-process: Retrieve PCI info from remote process

John G Johnson (1):
  multi-process: add the concept description to
    docs/devel/qemu-multiprocess

Stefan Hajnoczi (6):
  .github: point Repo Lockdown bot to GitLab repo
  gitmodules: use GitLab repos instead of qemu.org
  gitlab-ci: remove redundant GitLab repo URL command
  docs: update README to use GitLab repo URLs
  pc-bios: update mirror URLs to GitLab
  get_maintainer: update repo URL to GitLab

MAINTAINERS                               |  24 +
 README.rst                                |   4 +-
 docs/devel/index.rst                      |   1 +
 docs/devel/multi-process.rst              | 966 ++++++++++++++++++++++
 docs/system/index.rst                     |   1 +
 docs/system/multi-process.rst             |  64 ++
 docs/interop/parallels.txt                |   2 +-
 configure                                 |  10 +
 meson.build                               |   5 +-
 hw/remote/trace.h                         |   1 +
 include/exec/memory.h                     |   2 +
 include/exec/ram_addr.h                   |   4 +-
 include/hw/pci-host/remote.h              |  30 +
 include/hw/pci/pci_ids.h                  |   3 +
 include/hw/remote/iohub.h                 |  42 +
 include/hw/remote/machine.h               |  38 +
 include/hw/remote/memory.h                |  19 +
 include/hw/remote/mpqemu-link.h           |  99 +++
 include/hw/remote/proxy-memory-listener.h |  28 +
 include/hw/remote/proxy.h                 |  48 ++
 include/io/channel.h                      |  78 ++
 include/qemu/mmap-alloc.h                 |   4 +-
 include/sysemu/iothread.h                 |   6 +
 backends/hostmem-memfd.c                  |   2 +-
 hw/misc/ivshmem.c                         |   3 +-
 hw/pci-host/remote.c                      |  75 ++
 hw/remote/iohub.c                         | 119 +++
 hw/remote/machine.c                       |  80 ++
 hw/remote/memory.c                        |  65 ++
 hw/remote/message.c                       | 230 ++++++
 hw/remote/mpqemu-link.c                   | 267 ++++++
 hw/remote/proxy-memory-listener.c         | 227 +++++
 hw/remote/proxy.c                         | 379 +++++++++
 hw/remote/remote-obj.c                    | 203 +++++
 io/channel.c                              | 116 ++-
 iothread.c                                |   6 +
 softmmu/memory.c                          |   3 +-
 softmmu/physmem.c                         |  12 +-
 util/mmap-alloc.c                         |   8 +-
 util/oslib-posix.c                        |   2 +-
 .github/lockdown.yml                      |   8 +-
 .gitlab-ci.yml                            |   1 -
 .gitmodules                               |  44 +-
 Kconfig.host                              |   4 +
 hw/Kconfig                                |   1 +
 hw/meson.build                            |   1 +
 hw/pci-host/Kconfig                       |   3 +
 hw/pci-host/meson.build                   |   1 +
 hw/remote/Kconfig                         |   4 +
 hw/remote/meson.build                     |  13 +
 hw/remote/trace-events                    |   4 +
 pc-bios/README                            |   4 +-
 scripts/get_maintainer.pl                 |   2 +-
 53 files changed, 3296 insertions(+), 70 deletions(-)
 create mode 100644 docs/devel/multi-process.rst
 create mode 100644 docs/system/multi-process.rst
 create mode 100644 hw/remote/trace.h
 create mode 100644 include/hw/pci-host/remote.h
 create mode 100644 include/hw/remote/iohub.h
 create mode 100644 include/hw/remote/machine.h
 create mode 100644 include/hw/remote/memory.h
 create mode 100644 include/hw/remote/mpqemu-link.h
 create mode 100644 include/hw/remote/proxy-memory-listener.h
 create mode 100644 include/hw/remote/proxy.h
 create mode 100644 hw/pci-host/remote.c
 create mode 100644 hw/remote/iohub.c
 create mode 100644 hw/remote/machine.c
 create mode 100644 hw/remote/memory.c
 create mode 100644 hw/remote/message.c
 create mode 100644 hw/remote/mpqemu-link.c
 create mode 100644 hw/remote/proxy-memory-listener.c
 create mode 100644 hw/remote/proxy.c
 create mode 100644 hw/remote/remote-obj.c
 create mode 100644 hw/remote/Kconfig
 create mode 100644 hw/remote/meson.build
 create mode 100644 hw/remote/trace-events

-- 
2.29.2

Use the GitLab repo URL as the main repo location in order to reduce
load on qemu.org.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-id: 20210111115017.156802-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 .github/lockdown.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/lockdown.yml b/.github/lockdown.yml
index XXXXXXX..XXXXXXX 100644
--- a/.github/lockdown.yml
+++ b/.github/lockdown.yml
@@ -XXX,XX +XXX,XX @@ issues:
   comment: |
     Thank you for your interest in the QEMU project.
 
-    This repository is a read-only mirror of the project's master
-    repostories hosted on https://git.qemu.org/git/qemu.git.
+    This repository is a read-only mirror of the project's repostories hosted
+    at https://gitlab.com/qemu-project/qemu.git.
     The project does not process issues filed on GitHub.
 
     The project issues are tracked on Launchpad:
@@ -XXX,XX +XXX,XX @@ pulls:
   comment: |
     Thank you for your interest in the QEMU project.
 
-    This repository is a read-only mirror of the project's master
-    repostories hosted on https://git.qemu.org/git/qemu.git.
+    This repository is a read-only mirror of the project's repostories hosted
+    on https://gitlab.com/qemu-project/qemu.git.
     The project does not process merge requests filed on GitHub.
 
     QEMU welcomes contributions of code (either fixing bugs or adding new
-- 
2.29.2

qemu.org is running out of bandwidth and the QEMU project is moving
towards a gating CI on GitLab. Use the GitLab repos instead of qemu.org
(they will become mirrors).

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210111115017.156802-3-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 .gitmodules | 44 ++++++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/.gitmodules b/.gitmodules
index XXXXXXX..XXXXXXX 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -XXX,XX +XXX,XX @@
 [submodule "roms/seabios"]
 	path = roms/seabios
-	url = https://git.qemu.org/git/seabios.git/
+	url = https://gitlab.com/qemu-project/seabios.git/
 [submodule "roms/SLOF"]
 	path = roms/SLOF
-	url = https://git.qemu.org/git/SLOF.git
+	url = https://gitlab.com/qemu-project/SLOF.git
 [submodule "roms/ipxe"]
 	path = roms/ipxe
-	url = https://git.qemu.org/git/ipxe.git
+	url = https://gitlab.com/qemu-project/ipxe.git
 [submodule "roms/openbios"]
 	path = roms/openbios
-	url = https://git.qemu.org/git/openbios.git
+	url = https://gitlab.com/qemu-project/openbios.git
 [submodule "roms/qemu-palcode"]
 	path = roms/qemu-palcode
-	url = https://git.qemu.org/git/qemu-palcode.git
+	url = https://gitlab.com/qemu-project/qemu-palcode.git
 [submodule "roms/sgabios"]
 	path = roms/sgabios
-	url = https://git.qemu.org/git/sgabios.git
+	url = https://gitlab.com/qemu-project/sgabios.git
 [submodule "dtc"]
 	path = dtc
-	url = https://git.qemu.org/git/dtc.git
+	url = https://gitlab.com/qemu-project/dtc.git
 [submodule "roms/u-boot"]
 	path = roms/u-boot
-	url = https://git.qemu.org/git/u-boot.git
+	url = https://gitlab.com/qemu-project/u-boot.git
 [submodule "roms/skiboot"]
 	path = roms/skiboot
-	url = https://git.qemu.org/git/skiboot.git
+	url = https://gitlab.com/qemu-project/skiboot.git
 [submodule "roms/QemuMacDrivers"]
 	path = roms/QemuMacDrivers
-	url = https://git.qemu.org/git/QemuMacDrivers.git
+	url = https://gitlab.com/qemu-project/QemuMacDrivers.git
 [submodule "ui/keycodemapdb"]
 	path = ui/keycodemapdb
-	url = https://git.qemu.org/git/keycodemapdb.git
+	url = https://gitlab.com/qemu-project/keycodemapdb.git
 [submodule "capstone"]
 	path = capstone
-	url = https://git.qemu.org/git/capstone.git
+	url = https://gitlab.com/qemu-project/capstone.git
 [submodule "roms/seabios-hppa"]
 	path = roms/seabios-hppa
-	url = https://git.qemu.org/git/seabios-hppa.git
+	url = https://gitlab.com/qemu-project/seabios-hppa.git
 [submodule "roms/u-boot-sam460ex"]
 	path = roms/u-boot-sam460ex
-	url = https://git.qemu.org/git/u-boot-sam460ex.git
+	url = https://gitlab.com/qemu-project/u-boot-sam460ex.git
 [submodule "tests/fp/berkeley-testfloat-3"]
 	path = tests/fp/berkeley-testfloat-3
-	url = https://git.qemu.org/git/berkeley-testfloat-3.git
+	url = https://gitlab.com/qemu-project/berkeley-testfloat-3.git
 [submodule "tests/fp/berkeley-softfloat-3"]
 	path = tests/fp/berkeley-softfloat-3
-	url = https://git.qemu.org/git/berkeley-softfloat-3.git
+	url = https://gitlab.com/qemu-project/berkeley-softfloat-3.git
 [submodule "roms/edk2"]
 	path = roms/edk2
-	url = https://git.qemu.org/git/edk2.git
+	url = https://gitlab.com/qemu-project/edk2.git
 [submodule "slirp"]
 	path = slirp
-	url = https://git.qemu.org/git/libslirp.git
+	url = https://gitlab.com/qemu-project/libslirp.git
 [submodule "roms/opensbi"]
 	path = roms/opensbi
-	url = 	https://git.qemu.org/git/opensbi.git
+	url = 	https://gitlab.com/qemu-project/opensbi.git
 [submodule "roms/qboot"]
 	path = roms/qboot
-	url = https://git.qemu.org/git/qboot.git
+	url = https://gitlab.com/qemu-project/qboot.git
 [submodule "meson"]
 	path = meson
-	url = https://git.qemu.org/git/meson.git
+	url = https://gitlab.com/qemu-project/meson.git
 [submodule "roms/vbootrom"]
 	path = roms/vbootrom
-	url = https://git.qemu.org/git/vbootrom.git
+	url = https://gitlab.com/qemu-project/vbootrom.git
-- 
2.29.2

qemu.org is running out of bandwidth and the QEMU project is moving
towards a gating CI on GitLab. Use the GitLab repos instead of qemu.org
(they will become mirrors).

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210111115017.156802-5-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 README.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/README.rst b/README.rst
index XXXXXXX..XXXXXXX 100644
--- a/README.rst
+++ b/README.rst
@@ -XXX,XX +XXX,XX @@ The QEMU source code is maintained under the GIT version control system.
 
 .. code-block:: shell
 
-   git clone https://git.qemu.org/git/qemu.git
+   git clone https://gitlab.com/qemu-project/qemu.git
 
 When submitting patches, one common approach is to use 'git
 format-patch' and/or 'git send-email' to format & send the mail to the
@@ -XXX,XX +XXX,XX @@ The QEMU website is also maintained under source control.
 
 .. code-block:: shell
 
-  git clone https://git.qemu.org/git/qemu-web.git
+  git clone https://gitlab.com/qemu-project/qemu-web.git
 
 * `<https://www.qemu.org/2017/02/04/the-new-qemu-website-is-up/>`_
 
-- 
2.29.2

qemu.org is running out of bandwidth and the QEMU project is moving
towards a gating CI on GitLab. Use the GitLab repos instead of qemu.org
(they will become mirrors).

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210111115017.156802-6-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 pc-bios/README | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pc-bios/README b/pc-bios/README
index XXXXXXX..XXXXXXX 100644
--- a/pc-bios/README
+++ b/pc-bios/README
@@ -XXX,XX +XXX,XX @@
   legacy x86 software to communicate with an attached serial console as
   if a video card were attached.  The master sources reside in a subversion
   repository at http://sgabios.googlecode.com/svn/trunk.  A git mirror is
-  available at https://git.qemu.org/git/sgabios.git.
+  available at https://gitlab.com/qemu-project/sgabios.git.
 
 - The PXE roms come from the iPXE project. Built with BANNER_TIME 0.
   Sources available at http://ipxe.org.  Vendor:Device ID -> ROM mapping:
@@ -XXX,XX +XXX,XX @@
 
 - The u-boot binary for e500 comes from the upstream denx u-boot project where
   it was compiled using the qemu-ppce500 target.
-  A git mirror is available at: https://git.qemu.org/git/u-boot.git
+  A git mirror is available at: https://gitlab.com/qemu-project/u-boot.git
   The hash used to compile the current version is: 2072e72
 
 - Skiboot (https://github.com/open-power/skiboot/) is an OPAL
-- 
2.29.2

qemu.org is running out of bandwidth and the QEMU project is moving
towards a gating CI on GitLab. Use the GitLab repos instead of qemu.org
(they will become mirrors).

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210111115017.156802-7-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 scripts/get_maintainer.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/get_maintainer.pl b/scripts/get_maintainer.pl
index XXXXXXX..XXXXXXX 100755
--- a/scripts/get_maintainer.pl
+++ b/scripts/get_maintainer.pl
@@ -XXX,XX +XXX,XX @@ sub vcs_exists {
 	warn("$P: No supported VCS found.  Add --nogit to options?\n");
 	warn("Using a git repository produces better results.\n");
 	warn("Try latest git repository using:\n");
-	warn("git clone https://git.qemu.org/git/qemu.git\n");
+	warn("git clone https://gitlab.com/qemu-project/qemu.git\n");
 	$printed_novcs = 1;
     }
     return 0;
-- 
2.29.2

From: John G Johnson <john.g.johnson@oracle.com>

Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 02a68adef99f5df6a380bf8fd7b90948777e411c.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS                  |   7 +
 docs/devel/index.rst         |   1 +
 docs/devel/multi-process.rst | 966 +++++++++++++++++++++++++++++++++++
 3 files changed, 974 insertions(+)
 create mode 100644 docs/devel/multi-process.rst

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ S: Maintained
 F: hw/semihosting/
 F: include/hw/semihosting/
 
+Multi-process QEMU
+M: Elena Ufimtseva <elena.ufimtseva@oracle.com>
+M: Jagannathan Raman <jag.raman@oracle.com>
+M: John G Johnson <john.g.johnson@oracle.com>
+S: Maintained
+F: docs/devel/multi-process.rst
+
 Build and test automation
 -------------------------
 Build and test automation
diff --git a/docs/devel/index.rst b/docs/devel/index.rst
index XXXXXXX..XXXXXXX 100644
--- a/docs/devel/index.rst
+++ b/docs/devel/index.rst
@@ -XXX,XX +XXX,XX @@ Contents:
    clocks
    qom
    block-coroutine-wrapper
+   multi-process
diff --git a/docs/devel/multi-process.rst b/docs/devel/multi-process.rst
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/docs/devel/multi-process.rst
@@ -XXX,XX +XXX,XX @@
+This is the design document for multi-process QEMU. It does not
+necessarily reflect the status of the current implementation, which
+may lack features or be considerably different from what is described
+in this document. This document is still useful as a description of
+the goals and general direction of this feature.
+
+Please refer to the following wiki for latest details:
+https://wiki.qemu.org/Features/MultiProcessQEMU
+
+Multi-process QEMU
+===================
+
+QEMU is often used as the hypervisor for virtual machines running in the
+Oracle cloud. Since one of the advantages of cloud computing is the
+ability to run many VMs from different tenants in the same cloud
+infrastructure, a guest that compromised its hypervisor could
+potentially use the hypervisor's access privileges to access data it is
+not authorized for.
+
+QEMU can be susceptible to security attacks because it is a large,
+monolithic program that provides many features to the VMs it services.
+Many of these features can be configured out of QEMU, but even a reduced
+configuration QEMU has a large amount of code a guest can potentially
+attack. Separating QEMU reduces the attack surface by aiding to
+limit each component in the system to only access the resources that
+it needs to perform its job.
+
+QEMU services
+-------------
+
+QEMU can be broadly described as providing three main services. One is a
+VM control point, where VMs can be created, migrated, re-configured, and
+destroyed. A second is to emulate the CPU instructions within the VM,
+often accelerated by HW virtualization features such as Intel's VT
+extensions. Finally, it provides IO services to the VM by emulating HW
+IO devices, such as disk and network devices.
+
+A multi-process QEMU
+~~~~~~~~~~~~~~~~~~~~
+
+A multi-process QEMU involves separating QEMU services into separate
+host processes. Each of these processes can be given only the privileges
+it needs to provide its service, e.g., a disk service could be given
+access only to the disk images it provides, and not be allowed to
+access other files, or any network devices. An attacker who compromised
+this service would not be able to use this exploit to access files or
+devices beyond what the disk service was given access to.
+
+A QEMU control process would remain, but in multi-process mode, will
+have no direct interfaces to the VM. During VM execution, it would still
+provide the user interface to hot-plug devices or live migrate the VM.
+
+A first step in creating a multi-process QEMU is to separate IO services
+from the main QEMU program, which would continue to provide CPU
+emulation. i.e., the control process would also be the CPU emulation
+process. In a later phase, CPU emulation could be separated from the
+control process.
+
+Separating IO services
+----------------------
+
+Separating IO services into individual host processes is a good place to
+begin for a couple of reasons. One is the sheer number of IO devices QEMU
+can emulate provides a large surface of interfaces which could potentially
+be exploited, and, indeed, have been a source of exploits in the past.
+Another is the modular nature of QEMU device emulation code provides
+interface points where the QEMU functions that perform device emulation
+can be separated from the QEMU functions that manage the emulation of
+guest CPU instructions. The devices emulated in the separate process are
+referred to as remote devices.
+
+QEMU device emulation
+~~~~~~~~~~~~~~~~~~~~~
+
+QEMU uses an object oriented SW architecture for device emulation code.
+Configured objects are all compiled into the QEMU binary, then objects
+are instantiated by name when used by the guest VM. For example, the
+code to emulate a device named "foo" is always present in QEMU, but its
+instantiation code is only run when the device is included in the target
+VM. (e.g., via the QEMU command line as *-device foo*)
+
+The object model is hierarchical, so device emulation code names its
+parent object (such as "pci-device" for a PCI device) and QEMU will
+instantiate a parent object before calling the device's instantiation
+code.
+
+Current separation models
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In order to separate the device emulation code from the CPU emulation
+code, the device object code must run in a different process. There are
+a couple of existing QEMU features that can run emulation code
+separately from the main QEMU process. These are examined below.
+
+vhost user model
+^^^^^^^^^^^^^^^^
+
+Virtio guest device drivers can be connected to vhost user applications
+in order to perform their IO operations. This model uses special virtio
+device drivers in the guest and vhost user device objects in QEMU, but
+once the QEMU vhost user code has configured the vhost user application,
+mission-mode IO is performed by the application. The vhost user
+application is a daemon process that can be contacted via a known UNIX
+domain socket.
+
+vhost socket
+''''''''''''
+
+As mentioned above, one of the tasks of the vhost device object within
+QEMU is to contact the vhost application and send it configuration
+information about this device instance. As part of the configuration
+process, the application can also be sent other file descriptors over
+the socket, which then can be used by the vhost user application in
+various ways, some of which are described below.
+
+vhost MMIO store acceleration
+'''''''''''''''''''''''''''''
+
+VMs are often run using HW virtualization features via the KVM kernel
+driver. This driver allows QEMU to accelerate the emulation of guest CPU
+instructions by running the guest in a virtual HW mode. When the guest
+executes instructions that cannot be executed by virtual HW mode,
+execution returns to the KVM driver so it can inform QEMU to emulate the
+instructions in SW.
+
+One of the events that can cause a return to QEMU is when a guest device
+driver accesses an IO location. QEMU then dispatches the memory
+operation to the corresponding QEMU device object. In the case of a
+vhost user device, the memory operation would need to be sent over a
+socket to the vhost application. This path is accelerated by the QEMU
+virtio code by setting up an eventfd file descriptor that the vhost
+application can directly receive MMIO store notifications from the KVM
+driver, instead of needing them to be sent to the QEMU process first.
+
+vhost interrupt acceleration
+''''''''''''''''''''''''''''
+
+Another optimization used by the vhost application is the ability to
+directly inject interrupts into the VM via the KVM driver, again,
+bypassing the need to send the interrupt back to the QEMU process first.
+The QEMU virtio setup code configures the KVM driver with an eventfd
+that triggers the device interrupt in the guest when the eventfd is
+written. This irqfd file descriptor is then passed to the vhost user
+application program.
+
+vhost access to guest memory
+''''''''''''''''''''''''''''
+
+The vhost application is also allowed to directly access guest memory,
+instead of needing to send the data as messages to QEMU. This is also
+done with file descriptors sent to the vhost user application by QEMU.
+These descriptors can be passed to ``mmap()`` by the vhost application
+to map the guest address space into the vhost application.
+
+IOMMUs introduce another level of complexity, since the address given to
+the guest virtio device to DMA to or from is not a guest physical
+address. This case is handled by having vhost code within QEMU register
+as a listener for IOMMU mapping changes. The vhost application maintains
+a cache of IOMMMU translations: sending translation requests back to
+QEMU on cache misses, and in turn receiving flush requests from QEMU
+when mappings are purged.
+
+applicability to device separation
+''''''''''''''''''''''''''''''''''
+
+Much of the vhost model can be re-used by separated device emulation. In
+particular, the ideas of using a socket between QEMU and the device
+emulation application, using a file descriptor to inject interrupts into
+the VM via KVM, and allowing the application to ``mmap()`` the guest
+should be re used.
+
+There are, however, some notable differences between how a vhost
+application works and the needs of separated device emulation. The most
+basic is that vhost uses custom virtio device drivers which always
+trigger IO with MMIO stores. A separated device emulation model must
+work with existing IO device models and guest device drivers. MMIO loads
+break vhost store acceleration since they are synchronous - guest
+progress cannot continue until the load has been emulated. By contrast,
+stores are asynchronous, the guest can continue after the store event
+has been sent to the vhost application.
+
+Another difference is that in the vhost user model, a single daemon can
+support multiple QEMU instances. This is contrary to the security regime
+desired, in which the emulation application should only be allowed to
+access the files or devices the VM it's running on behalf of can access.
+#### qemu-io model
+
+Qemu-io is a test harness used to test changes to the QEMU block backend
+object code. (e.g., the code that implements disk images for disk driver
+emulation) Qemu-io is not a device emulation application per se, but it
+does compile the QEMU block objects into a separate binary from the main
+QEMU one. This could be useful for disk device emulation, since its
+emulation applications will need to include the QEMU block objects.
+
+New separation model based on proxy objects
+-------------------------------------------
+
+A different model based on proxy objects in the QEMU program
+communicating with remote emulation programs could provide separation
+while minimizing the changes needed to the device emulation code. The
+rest of this section is a discussion of how a proxy object model would
+work.
+
+Remote emulation processes
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The remote emulation process will run the QEMU object hierarchy without
+modification. The device emulation objects will be also be based on the
+QEMU code, because for anything but the simplest device, it would not be
+a tractable to re-implement both the object model and the many device
+backends that QEMU has.
+
+The processes will communicate with the QEMU process over UNIX domain
+sockets. The processes can be executed either as standalone processes,
+or be executed by QEMU. In both cases, the host backends the emulation
+processes will provide are specified on its command line, as they would
+be for QEMU. For example:
+
+::
+
+    disk-proc -blockdev driver=file,node-name=file0,filename=disk-file0  \
+    -blockdev driver=qcow2,node-name=drive0,file=file0
+
+would indicate process *disk-proc* uses a qcow2 emulated disk named
+*file0* as its backend.
+
+Emulation processes may emulate more than one guest controller. A common
+configuration might be to put all controllers of the same device class
+(e.g., disk, network, etc.) in a single process, so that all backends of
+the same type can be managed by a single QMP monitor.
+
+communication with QEMU
+^^^^^^^^^^^^^^^^^^^^^^^
+
+The first argument to the remote emulation process will be a Unix domain
+socket that connects with the Proxy object. This is a required argument.
+
+::
+
+    disk-proc <socket number> <backend list>
+
+remote process QMP monitor
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Remote emulation processes can be monitored via QMP, similar to QEMU
+itself. The QMP monitor socket is specified the same as for a QEMU
+process:
+
+::
+
+    disk-proc -qmp unix:/tmp/disk-mon,server
+
+can be monitored over the UNIX socket path */tmp/disk-mon*.
+
+QEMU command line
+~~~~~~~~~~~~~~~~~
+
+Each remote device emulated in a remote process on the host is
+represented as a *-device* of type *pci-proxy-dev*. A socket
+sub-option to this option specifies the Unix socket that connects
+to the remote process. An *id* sub-option is required, and it should
+be the same id as used in the remote process.
+
+::
+
+    qemu-system-x86_64 ... -device pci-proxy-dev,id=lsi0,socket=3
+
+can be used to add a device emulated in a remote process
+
+
+QEMU management of remote processes
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+QEMU is not aware of the type of type of the remote PCI device. It is
+a pass through device as far as QEMU is concerned.
+
+communication with emulation process
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+primary channel
+'''''''''''''''
+
+The primary channel (referred to as com in the code) is used to bootstrap
+the remote process. It is also used to pass on device-agnostic commands
+like reset.
+
+per-device channels
+'''''''''''''''''''
+
+Each remote device communicates with QEMU using a dedicated communication
+channel. The proxy object sets up this channel using the primary
+channel during its initialization.
+
+QEMU device proxy objects
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+QEMU has an object model based on sub-classes inherited from the
+"object" super-class. The sub-classes that are of interest here are the
+"device" and "bus" sub-classes whose child sub-classes make up the
+device tree of a QEMU emulated system.
+
+The proxy object model will use device proxy objects to replace the
+device emulation code within the QEMU process. These objects will live
+in the same place in the object and bus hierarchies as the objects they
+replace. i.e., the proxy object for an LSI SCSI controller will be a
+sub-class of the "pci-device" class, and will have the same PCI bus
+parent and the same SCSI bus child objects as the LSI controller object
+it replaces.
+
+It is worth noting that the same proxy object is used to mediate with
+all types of remote PCI devices.
+
+object initialization
+^^^^^^^^^^^^^^^^^^^^^
+
+The Proxy device objects are initialized in the exact same manner in
+which any other QEMU device would be initialized.
+
+In addition, the Proxy objects perform the following two tasks:
+- Parses the "socket" sub option and connects to the remote process
+using this channel
+- Uses the "id" sub-option to connect to the emulated device on the
+separate process
+
+class\_init
+'''''''''''
+
+The ``class_init()`` method of a proxy object will, in general behave
+similarly to the object it replaces, including setting any static
+properties and methods needed by the proxy.
+
+instance\_init / realize
+''''''''''''''''''''''''
+
+The ``instance_init()`` and ``realize()`` functions would only need to
+perform tasks related to being a proxy, such are registering its own
+MMIO handlers, or creating a child bus that other proxy devices can be
+attached to later.
+
+Other tasks will be device-specific. For example, PCI device objects
+will initialize the PCI config space in order to make a valid PCI device
+tree within the QEMU process.
+
+address space registration
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Most devices are driven by guest device driver accesses to IO addresses
+or ports. The QEMU device emulation code uses QEMU's memory region
+function calls (such as ``memory_region_init_io()``) to add callback
+functions that QEMU will invoke when the guest accesses the device's
+areas of the IO address space. When a guest driver does access the
+device, the VM will exit HW virtualization mode and return to QEMU,
+which will then lookup and execute the corresponding callback function.
+
+A proxy object would need to mirror the memory region calls the actual
+device emulator would perform in its initialization code, but with its
+own callbacks. When invoked by QEMU as a result of a guest IO operation,
+they will forward the operation to the device emulation process.
+
+PCI config space
+^^^^^^^^^^^^^^^^
+
+PCI devices also have a configuration space that can be accessed by the
+guest driver. Guest accesses to this space is not handled by the device
+emulation object, but by its PCI parent object. Much of this space is
+read-only, but certain registers (especially BAR and MSI-related ones)
+need to be propagated to the emulation process.
+
+PCI parent proxy
+''''''''''''''''
+
+One way to propagate guest PCI config accesses is to create a
+"pci-device-proxy" class that can serve as the parent of a PCI device
+proxy object. This class's parent would be "pci-device" and it would
+override the PCI parent's ``config_read()`` and ``config_write()``
+methods with ones that forward these operations to the emulation
+program.
+
+interrupt receipt
+^^^^^^^^^^^^^^^^^
+
+A proxy for a device that generates interrupts will need to create a
+socket to receive interrupt indications from the emulation process. An
+incoming interrupt indication would then be sent up to its bus parent to
+be injected into the guest. For example, a PCI device object may use
+``pci_set_irq()``.
+
+live migration
+^^^^^^^^^^^^^^
+
+The proxy will register to save and restore any *vmstate* it needs over
+a live migration event. The device proxy does not need to manage the
+remote device's *vmstate*; that will be handled by the remote process
+proxy (see below).
+
+QEMU remote device operation
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Generic device operations, such as DMA, will be performed by the remote
+process proxy by sending messages to the remote process.
+
+DMA operations
+^^^^^^^^^^^^^^
+
+DMA operations would be handled much like vhost applications do. One of
+the initial messages sent to the emulation process is a guest memory
+table. Each entry in this table consists of a file descriptor and size
+that the emulation process can ``mmap()`` to directly access guest
+memory, similar to ``vhost_user_set_mem_table()``. Note guest memory
+must be backed by file descriptors, such as when QEMU is given the
+*-mem-path* command line option.
+
+IOMMU operations
+^^^^^^^^^^^^^^^^
+
+When the emulated system includes an IOMMU, the remote process proxy in
+QEMU will need to create a socket for IOMMU requests from the emulation
+process. It will handle those requests with an
+``address_space_get_iotlb_entry()`` call. In order to handle IOMMU
+unmaps, the remote process proxy will also register as a listener on the
+device's DMA address space. When an IOMMU memory region is created
+within the DMA address space, an IOMMU notifier for unmaps will be added
+to the memory region that will forward unmaps to the emulation process
+over the IOMMU socket.
+
+device hot-plug via QMP
+^^^^^^^^^^^^^^^^^^^^^^^
+
+An QMP "device\_add" command can add a device emulated by a remote
+process. It will also have "rid" option to the command, just as the
+*-device* command line option does. The remote process may either be one
+started at QEMU startup, or be one added by the "add-process" QMP
+command described above. In either case, the remote process proxy will
+forward the new device's JSON description to the corresponding emulation
+process.
+
+live migration
+^^^^^^^^^^^^^^
+
+The remote process proxy will also register for live migration
+notifications with ``vmstate_register()``. When called to save state,
+the proxy will send the remote process a secondary socket file
+descriptor to save the remote process's device *vmstate* over. The
+incoming byte stream length and data will be saved as the proxy's
+*vmstate*. When the proxy is resumed on its new host, this *vmstate*
+will be extracted, and a secondary socket file descriptor will be sent
+to the new remote process through which it receives the *vmstate* in
+order to restore the devices there.
+
+device emulation in remote process
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The parts of QEMU that the emulation program will need include the
+object model; the memory emulation objects; the device emulation objects
+of the targeted device, and any dependent devices; and, the device's
+backends. It will also need code to setup the machine environment,
+handle requests from the QEMU process, and route machine-level requests
+(such as interrupts or IOMMU mappings) back to the QEMU process.
+
+initialization
+^^^^^^^^^^^^^^
+
+The process initialization sequence will follow the same sequence
+followed by QEMU. It will first initialize the backend objects, then
+device emulation objects. The JSON descriptions sent by the QEMU process
+will drive which objects need to be created.
+
+-  address spaces
+
+Before the device objects are created, the initial address spaces and
+memory regions must be configured with ``memory_map_init()``. This
+creates a RAM memory region object (*system\_memory*) and an IO memory
+region object (*system\_io*).
+
+-  RAM
+
+RAM memory region creation will follow how ``pc_memory_init()`` creates
+them, but must use ``memory_region_init_ram_from_fd()`` instead of
+``memory_region_allocate_system_memory()``. The file descriptors needed
+will be supplied by the guest memory table from above. Those RAM regions
+would then be added to the *system\_memory* memory region with
+``memory_region_add_subregion()``.
+
+-  PCI
+
+IO initialization will be driven by the JSON descriptions sent from the
+QEMU process. For a PCI device, a PCI bus will need to be created with
+``pci_root_bus_new()``, and a PCI memory region will need to be created
+and added to the *system\_memory* memory region with
+``memory_region_add_subregion_overlap()``. The overlap version is
+required for architectures where PCI memory overlaps with RAM memory.
+
+MMIO handling
+^^^^^^^^^^^^^
+
+The device emulation objects will use ``memory_region_init_io()`` to
+install their MMIO handlers, and ``pci_register_bar()`` to associate
+those handlers with a PCI BAR, as they do within QEMU currently.
+
+In order to use ``address_space_rw()`` in the emulation process to
+handle MMIO requests from QEMU, the PCI physical addresses must be the
+same in the QEMU process and the device emulation process. In order to
+accomplish that, guest BAR programming must also be forwarded from QEMU
+to the emulation process.
+
+interrupt injection
+^^^^^^^^^^^^^^^^^^^
+
+When device emulation wants to inject an interrupt into the VM, the
+request climbs the device's bus object hierarchy until the point where a
+bus object knows how to signal the interrupt to the guest. The details
+depend on the type of interrupt being raised.
+
+-  PCI pin interrupts
+
+On x86 systems, there is an emulated IOAPIC object attached to the root
+PCI bus object, and the root PCI object forwards interrupt requests to
+it. The IOAPIC object, in turn, calls the KVM driver to inject the
+corresponding interrupt into the VM. The simplest way to handle this in
+an emulation process would be to setup the root PCI bus driver (via
+``pci_bus_irqs()``) to send a interrupt request back to the QEMU
+process, and have the device proxy object reflect it up the PCI tree
+there.
+
+-  PCI MSI/X interrupts
+
+PCI MSI/X interrupts are implemented in HW as DMA writes to a
+CPU-specific PCI address. In QEMU on x86, a KVM APIC object receives
+these DMA writes, then calls into the KVM driver to inject the interrupt
+into the VM. A simple emulation process implementation would be to send
+the MSI DMA address from QEMU as a message at initialization, then
+install an address space handler at that address which forwards the MSI
+message back to QEMU.
+
+DMA operations
+^^^^^^^^^^^^^^
+
+When a emulation object wants to DMA into or out of guest memory, it
+first must use dma\_memory\_map() to convert the DMA address to a local
+virtual address. The emulation process memory region objects setup above
+will be used to translate the DMA address to a local virtual address the
+device emulation code can access.
+
+IOMMU
+^^^^^
+
+When an IOMMU is in use in QEMU, DMA translation uses IOMMU memory
+regions to translate the DMA address to a guest physical address before
+that physical address can be translated to a local virtual address. The
+emulation process will need similar functionality.
+
+-  IOTLB cache
+
+The emulation process will maintain a cache of recent IOMMU translations
+(the IOTLB). When the translate() callback of an IOMMU memory region is
+invoked, the IOTLB cache will be searched for an entry that will map the
+DMA address to a guest PA. On a cache miss, a message will be sent back
+to QEMU requesting the corresponding translation entry, which be both be
+used to return a guest address and be added to the cache.
+
+-  IOTLB purge
+
+The IOMMU emulation will also need to act on unmap requests from QEMU.
+These happen when the guest IOMMU driver purges an entry from the
+guest's translation table.
+
+live migration
+^^^^^^^^^^^^^^
+
+When a remote process receives a live migration indication from QEMU, it
+will set up a channel using the received file descriptor with
+``qio_channel_socket_new_fd()``. This channel will be used to create a
+*QEMUfile* that can be passed to ``qemu_save_device_state()`` to send
+the process's device state back to QEMU. This method will be reversed on
+restore - the channel will be passed to ``qemu_loadvm_state()`` to
+restore the device state.
+
+Accelerating device emulation
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The messages that are required to be sent between QEMU and the emulation
+process can add considerable latency to IO operations. The optimizations
+described below attempt to ameliorate this effect by allowing the
+emulation process to communicate directly with the kernel KVM driver.
+The KVM file descriptors created would be passed to the emulation process
+via initialization messages, much like the guest memory table is done.
+#### MMIO acceleration
+
+Vhost user applications can receive guest virtio driver stores directly
+from KVM. The issue with the eventfd mechanism used by vhost user is
+that it does not pass any data with the event indication, so it cannot
+handle guest loads or guest stores that carry store data. This concept
+could, however, be expanded to cover more cases.
+
+The expanded idea would require a new type of KVM device:
+*KVM\_DEV\_TYPE\_USER*. This device has two file descriptors: a master
+descriptor that QEMU can use for configuration, and a slave descriptor
+that the emulation process can use to receive MMIO notifications. QEMU
+would create both descriptors using the KVM driver, and pass the slave
+descriptor to the emulation process via an initialization message.
+
+data structures
+^^^^^^^^^^^^^^^
+
+-  guest physical range
+
+The guest physical range structure describes the address range that a
+device will respond to. It includes the base and length of the range, as
+well as which bus the range resides on (e.g., on an x86machine, it can
+specify whether the range refers to memory or IO addresses).
+
+A device can have multiple physical address ranges it responds to (e.g.,
+a PCI device can have multiple BARs), so the structure will also include
+an enumerated identifier to specify which of the device's ranges is
+being referred to.
+
++--------+----------------------------+
+| Name   | Description                |
++========+============================+
+| addr   | range base address         |
++--------+----------------------------+
+| len    | range length               |
++--------+----------------------------+
+| bus    | addr type (memory or IO)   |
++--------+----------------------------+
+| id     | range ID (e.g., PCI BAR)   |
++--------+----------------------------+
+
+-  MMIO request structure
+
+This structure describes an MMIO operation. It includes which guest
+physical range the MMIO was within, the offset within that range, the
+MMIO type (e.g., load or store), and its length and data. It also
+includes a sequence number that can be used to reply to the MMIO, and
+the CPU that issued the MMIO.
+
++----------+------------------------+
+| Name     | Description            |
++==========+========================+
+| rid      | range MMIO is within   |
++----------+------------------------+
+| offset   | offset withing *rid*   |
++----------+------------------------+
+| type     | e.g., load or store    |
++----------+------------------------+
+| len      | MMIO length            |
++----------+------------------------+
+| data     | store data             |
++----------+------------------------+
+| seq      | sequence ID            |
++----------+------------------------+
+
+-  MMIO request queues
+
+MMIO request queues are FIFO arrays of MMIO request structures. There
+are two queues: pending queue is for MMIOs that haven't been read by the
+emulation program, and the sent queue is for MMIOs that haven't been
+acknowledged. The main use of the second queue is to validate MMIO
+replies from the emulation program.
+
+-  scoreboard
+
+Each CPU in the VM is emulated in QEMU by a separate thread, so multiple
+MMIOs may be waiting to be consumed by an emulation program and multiple
+threads may be waiting for MMIO replies. The scoreboard would contain a
+wait queue and sequence number for the per-CPU threads, allowing them to
+be individually woken when the MMIO reply is received from the emulation
+program. It also tracks the number of posted MMIO stores to the device
+that haven't been replied to, in order to satisfy the PCI constraint
+that a load to a device will not complete until all previous stores to
+that device have been completed.
+
+-  device shadow memory
+
+Some MMIO loads do not have device side-effects. These MMIOs can be
+completed without sending a MMIO request to the emulation program if the
+emulation program shares a shadow image of the device's memory image
+with the KVM driver.
+
+The emulation program will ask the KVM driver to allocate memory for the
+shadow image, and will then use ``mmap()`` to directly access it. The
+emulation program can control KVM access to the shadow image by sending
+KVM an access map telling it which areas of the image have no
+side-effects (and can be completed immediately), and which require a
+MMIO request to the emulation program. The access map can also inform
+the KVM drive which size accesses are allowed to the image.
+
+master descriptor
+^^^^^^^^^^^^^^^^^
+
+The master descriptor is used by QEMU to configure the new KVM device.
+The descriptor would be returned by the KVM driver when QEMU issues a
+*KVM\_CREATE\_DEVICE* ``ioctl()`` with a *KVM\_DEV\_TYPE\_USER* type.
+
+KVM\_DEV\_TYPE\_USER device ops
+
+
+The *KVM\_DEV\_TYPE\_USER* operations vector will be registered by a
+``kvm_register_device_ops()`` call when the KVM system in initialized by
+``kvm_init()``. These device ops are called by the KVM driver when QEMU
+executes certain ``ioctl()`` operations on its KVM file descriptor. They
+include:
+
+-  create
+
+This routine is called when QEMU issues a *KVM\_CREATE\_DEVICE*
+``ioctl()`` on its per-VM file descriptor. It will allocate and
+initialize a KVM user device specific data structure, and assign the
+*kvm\_device* private field to it.
+
+-  ioctl
+
+This routine is invoked when QEMU issues an ``ioctl()`` on the master
+descriptor. The ``ioctl()`` commands supported are defined by the KVM
+device type. *KVM\_DEV\_TYPE\_USER* ones will need several commands:
+
+*KVM\_DEV\_USER\_SLAVE\_FD* creates the slave file descriptor that will
+be passed to the device emulation program. Only one slave can be created
+by each master descriptor. The file operations performed by this
+descriptor are described below.
+
+The *KVM\_DEV\_USER\_PA\_RANGE* command configures a guest physical
+address range that the slave descriptor will receive MMIO notifications
+for. The range is specified by a guest physical range structure
+argument. For buses that assign addresses to devices dynamically, this
+command can be executed while the guest is running, such as the case
+when a guest changes a device's PCI BAR registers.
+
+*KVM\_DEV\_USER\_PA\_RANGE* will use ``kvm_io_bus_register_dev()`` to
+register *kvm\_io\_device\_ops* callbacks to be invoked when the guest
+performs a MMIO operation within the range. When a range is changed,
+``kvm_io_bus_unregister_dev()`` is used to remove the previous
+instantiation.
+
+*KVM\_DEV\_USER\_TIMEOUT* will configure a timeout value that specifies
+how long KVM will wait for the emulation process to respond to a MMIO
+indication.
+
+-  destroy
+
+This routine is called when the VM instance is destroyed. It will need
+to destroy the slave descriptor; and free any memory allocated by the
+driver, as well as the *kvm\_device* structure itself.
+
+slave descriptor
+^^^^^^^^^^^^^^^^
+
+The slave descriptor will have its own file operations vector, which
+responds to system calls on the descriptor performed by the device
+emulation program.
+
+-  read
+
+A read returns any pending MMIO requests from the KVM driver as MMIO
+request structures. Multiple structures can be returned if there are
+multiple MMIO operations pending. The MMIO requests are moved from the
+pending queue to the sent queue, and if there are threads waiting for
+space in the pending to add new MMIO operations, they will be woken
+here.
+
+-  write
+
+A write also consists of a set of MMIO requests. They are compared to
+the MMIO requests in the sent queue. Matches are removed from the sent
+queue, and any threads waiting for the reply are woken. If a store is
+removed, then the number of posted stores in the per-CPU scoreboard is
+decremented. When the number is zero, and a non side-effect load was
+waiting for posted stores to complete, the load is continued.
+
+-  ioctl
+
+There are several ioctl()s that can be performed on the slave
+descriptor.
+
+A *KVM\_DEV\_USER\_SHADOW\_SIZE* ``ioctl()`` causes the KVM driver to
+allocate memory for the shadow image. This memory can later be
+``mmap()``\ ed by the emulation process to share the emulation's view of
+device memory with the KVM driver.
+
+A *KVM\_DEV\_USER\_SHADOW\_CTRL* ``ioctl()`` controls access to the
+shadow image. It will send the KVM driver a shadow control map, which
+specifies which areas of the image can complete guest loads without
+sending the load request to the emulation program. It will also specify
+the size of load operations that are allowed.
+
+-  poll
+
+An emulation program will use the ``poll()`` call with a *POLLIN* flag
+to determine if there are MMIO requests waiting to be read. It will
+return if the pending MMIO request queue is not empty.
+
+-  mmap
+
+This call allows the emulation program to directly access the shadow
+image allocated by the KVM driver. As device emulation updates device
+memory, changes with no side-effects will be reflected in the shadow,
+and the KVM driver can satisfy guest loads from the shadow image without
+needing to wait for the emulation program.
+
+kvm\_io\_device ops
+^^^^^^^^^^^^^^^^^^^
+
+Each KVM per-CPU thread can handle MMIO operation on behalf of the guest
+VM. KVM will use the MMIO's guest physical address to search for a
+matching *kvm\_io\_device* to see if the MMIO can be handled by the KVM
+driver instead of exiting back to QEMU. If a match is found, the
+corresponding callback will be invoked.
+
+-  read
+
+This callback is invoked when the guest performs a load to the device.
+Loads with side-effects must be handled synchronously, with the KVM
+driver putting the QEMU thread to sleep waiting for the emulation
+process reply before re-starting the guest. Loads that do not have
+side-effects may be optimized by satisfying them from the shadow image,
+if there are no outstanding stores to the device by this CPU. PCI memory
+ordering demands that a load cannot complete before all older stores to
+the same device have been completed.
+
+-  write
+
+Stores can be handled asynchronously unless the pending MMIO request
+queue is full. In this case, the QEMU thread must sleep waiting for
+space in the queue. Stores will increment the number of posted stores in
+the per-CPU scoreboard, in order to implement the PCI ordering
+constraint above.
+
+interrupt acceleration
+^^^^^^^^^^^^^^^^^^^^^^
+
+This performance optimization would work much like a vhost user
+application does, where the QEMU process sets up *eventfds* that cause
+the device's corresponding interrupt to be triggered by the KVM driver.
+These irq file descriptors are sent to the emulation process at
+initialization, and are used when the emulation code raises a device
+interrupt.
+
+intx acceleration
+'''''''''''''''''
+
+Traditional PCI pin interrupts are level based, so, in addition to an
+irq file descriptor, a re-sampling file descriptor needs to be sent to
+the emulation program. This second file descriptor allows multiple
+devices sharing an irq to be notified when the interrupt has been
+acknowledged by the guest, so they can re-trigger the interrupt if their
+device has not de-asserted its interrupt.
+
+intx irq descriptor
+
+
+The irq descriptors are created by the proxy object
+``using event_notifier_init()`` to create the irq and re-sampling
+*eventds*, and ``kvm_vm_ioctl(KVM_IRQFD)`` to bind them to an interrupt.
+The interrupt route can be found with
+``pci_device_route_intx_to_irq()``.
+
+intx routing changes
+
+
+Intx routing can be changed when the guest programs the APIC the device
+pin is connected to. The proxy object in QEMU will use
+``pci_device_set_intx_routing_notifier()`` to be informed of any guest
+changes to the route. This handler will broadly follow the VFIO
+interrupt logic to change the route: de-assigning the existing irq
+descriptor from its route, then assigning it the new route. (see
+``vfio_intx_update()``)
+
+MSI/X acceleration
+''''''''''''''''''
+
+MSI/X interrupts are sent as DMA transactions to the host. The interrupt
+data contains a vector that is programmed by the guest, A device may have
+multiple MSI interrupts associated with it, so multiple irq descriptors
+may need to be sent to the emulation program.
+
+MSI/X irq descriptor
+
+
+This case will also follow the VFIO example. For each MSI/X interrupt,
+an *eventfd* is created, a virtual interrupt is allocated by
+``kvm_irqchip_add_msi_route()``, and the virtual interrupt is bound to
+the eventfd with ``kvm_irqchip_add_irqfd_notifier()``.
+
+MSI/X config space changes
+
+
+The guest may dynamically update several MSI-related tables in the
+device's PCI config space. These include per-MSI interrupt enables and
+vector data. Additionally, MSIX tables exist in device memory space, not
+config space. Much like the BAR case above, the proxy object must look
+at guest config space programming to keep the MSI interrupt state
+consistent between QEMU and the emulation program.
+
+--------------
+
+Disaggregated CPU emulation
+---------------------------
+
+After IO services have been disaggregated, a second phase would be to
+separate a process to handle CPU instruction emulation from the main
+QEMU control function. There are no object separation points for this
+code, so the first task would be to create one.
+
+Host access controls
+--------------------
+
+Separating QEMU relies on the host OS's access restriction mechanisms to
+enforce that the differing processes can only access the objects they
+are entitled to. There are a couple types of mechanisms usually provided
+by general purpose OSs.
+
+Discretionary access control
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Discretionary access control allows each user to control who can access
+their files. In Linux, this type of control is usually too coarse for
+QEMU separation, since it only provides three separate access controls:
+one for the same user ID, the second for users IDs with the same group
+ID, and the third for all other user IDs. Each device instance would
+need a separate user ID to provide access control, which is likely to be
+unwieldy for dynamically created VMs.
+
+Mandatory access control
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Mandatory access control allows the OS to add an additional set of
+controls on top of discretionary access for the OS to control. It also
+adds other attributes to processes and files such as types, roles, and
+categories, and can establish rules for how processes and files can
+interact.
+
+Type enforcement
+^^^^^^^^^^^^^^^^
+
+Type enforcement assigns a *type* attribute to processes and files, and
+allows rules to be written on what operations a process with a given
+type can perform on a file with a given type. QEMU separation could take
+advantage of type enforcement by running the emulation processes with
+different types, both from the main QEMU process, and from the emulation
+processes of different classes of devices.
+
+For example, guest disk images and disk emulation processes could have
+types separate from the main QEMU process and non-disk emulation
+processes, and the type rules could prevent processes other than disk
+emulation ones from accessing guest disk images. Similarly, network
+emulation processes can have a type separate from the main QEMU process
+and non-network emulation process, and only that type can access the
+host tun/tap device used to provide guest networking.
+
+Category enforcement
+^^^^^^^^^^^^^^^^^^^^
+
+Category enforcement assigns a set of numbers within a given range to
+the process or file. The process is granted access to the file if the
+process's set is a superset of the file's set. This enforcement can be
+used to separate multiple instances of devices in the same class.
+
+For example, if there are multiple disk devices provides to a guest,
+each device emulation process could be provisioned with a separate
+category. The different device emulation processes would not be able to
+access each other's backing disk images.
+
+Alternatively, categories could be used in lieu of the type enforcement
+scheme described above. In this scenario, different categories would be
+used to prevent device emulation processes in different classes from
+accessing resources assigned to other classes.
-- 
2.29.2

From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

Adds documentation explaining the command-line arguments needed
to use multi-process.

[Move orphan docs/multi-process.rst document into docs/system/ and add
it to index.rst to prevent Sphinx "document isn't included in any
toctree" error.
--Stefan]

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS                   |  1 +
 docs/system/index.rst         |  1 +
 docs/system/multi-process.rst | 64 +++++++++++++++++++++++++++++++++++
 3 files changed, 66 insertions(+)
 create mode 100644 docs/system/multi-process.rst

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ M: Jagannathan Raman <jag.raman@oracle.com>
 M: John G Johnson <john.g.johnson@oracle.com>
 S: Maintained
 F: docs/devel/multi-process.rst
+F: docs/system/multi-process.rst
 
 Build and test automation
 -------------------------
diff --git a/docs/system/index.rst b/docs/system/index.rst
index XXXXXXX..XXXXXXX 100644
--- a/docs/system/index.rst
+++ b/docs/system/index.rst
@@ -XXX,XX +XXX,XX @@ Contents:
    pr-manager
    targets
    security
+   multi-process
    deprecated
    removed-features
    build-platforms
diff --git a/docs/system/multi-process.rst b/docs/system/multi-process.rst
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/docs/system/multi-process.rst
@@ -XXX,XX +XXX,XX @@
+Multi-process QEMU
+==================
+
+This document describes how to configure and use multi-process qemu.
+For the design document refer to docs/devel/qemu-multiprocess.
+
+1) Configuration
+----------------
+
+multi-process is enabled by default for targets that enable KVM
+
+
+2) Usage
+--------
+
+Multi-process QEMU requires an orchestrator to launch.
+
+Following is a description of command-line used to launch mpqemu.
+
+* Orchestrator:
+
+  - The Orchestrator creates a unix socketpair
+
+  - It launches the remote process and passes one of the
+    sockets to it via command-line.
+
+  - It then launches QEMU and specifies the other socket as an option
+    to the Proxy device object
+
+* Remote Process:
+
+  - QEMU can enter remote process mode by using the "remote" machine
+    option.
+
+  - The orchestrator creates a "remote-object" with details about
+    the device and the file descriptor for the device
+
+  - The remaining options are no different from how one launches QEMU with
+    devices.
+
+  - Example command-line for the remote process is as follows:
+
+      /usr/bin/qemu-system-x86_64                                        \
+      -machine x-remote                                                  \
+      -device lsi53c895a,id=lsi0                                         \
+      -drive id=drive_image2,file=/build/ol7-nvme-test-1.qcow2           \
+      -device scsi-hd,id=drive2,drive=drive_image2,bus=lsi0.0,scsi-id=0  \
+      -object x-remote-object,id=robj1,devid=lsi1,fd=4,
+
+* QEMU:
+
+  - Since parts of the RAM are shared between QEMU & remote process, a
+    memory-backend-memfd is required to facilitate this, as follows:
+
+    -object memory-backend-memfd,id=mem,size=2G
+
+  - A "x-pci-proxy-dev" device is created for each of the PCI devices emulated
+    in the remote process. A "socket" sub-option specifies the other end of
+    unix channel created by orchestrator. The "id" sub-option must be specified
+    and should be the same as the "id" specified for the remote PCI device
+
+  - Example commandline for QEMU is as follows:
+
+      -device x-pci-proxy-dev,id=lsi0,socket=3
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

Allow RAM MemoryRegion to be created from an offset in a file, instead
of allocating at offset of 0 by default. This is needed to synchronize
RAM between QEMU & remote process.

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 609996697ad8617e3b01df38accc5c208c24d74e.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/exec/memory.h     |  2 ++
 include/exec/ram_addr.h   |  4 ++--
 include/qemu/mmap-alloc.h |  4 +++-
 backends/hostmem-memfd.c  |  2 +-
 hw/misc/ivshmem.c         |  3 ++-
 softmmu/memory.c          |  3 ++-
 softmmu/physmem.c         | 12 +++++++-----
 util/mmap-alloc.c         |  8 +++++---
 util/oslib-posix.c        |  2 +-
 9 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index XXXXXXX..XXXXXXX 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -XXX,XX +XXX,XX @@ void memory_region_init_ram_from_file(MemoryRegion *mr,
  * @size: size of the region.
  * @share: %true if memory must be mmaped with the MAP_SHARED flag
  * @fd: the fd to mmap.
+ * @offset: offset within the file referenced by fd
  * @errp: pointer to Error*, to store an error if it happens.
  *
  * Note that this function does not do anything to cause the data in the
@@ -XXX,XX +XXX,XX @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,
                                     uint64_t size,
                                     bool share,
                                     int fd,
+                                    ram_addr_t offset,
                                     Error **errp);
 #endif
 
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index XXXXXXX..XXXXXXX 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -XXX,XX +XXX,XX @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
                                    uint32_t ram_flags, const char *mem_path,
                                    bool readonly, Error **errp);
 RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
-                                 uint32_t ram_flags, int fd, bool readonly,
-                                 Error **errp);
+                                 uint32_t ram_flags, int fd, off_t offset,
+                                 bool readonly, Error **errp);
 
 RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
                                   MemoryRegion *mr, Error **errp);
diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/mmap-alloc.h
+++ b/include/qemu/mmap-alloc.h
@@ -XXX,XX +XXX,XX @@ size_t qemu_mempath_getpagesize(const char *mem_path);
  *  @readonly: true for a read-only mapping, false for read/write.
  *  @shared: map has RAM_SHARED flag.
  *  @is_pmem: map has RAM_PMEM flag.
+ *  @map_offset: map starts at offset of map_offset from the start of fd
  *
  * Return:
  *  On success, return a pointer to the mapped area.
@@ -XXX,XX +XXX,XX @@ void *qemu_ram_mmap(int fd,
                     size_t align,
                     bool readonly,
                     bool shared,
-                    bool is_pmem);
+                    bool is_pmem,
+                    off_t map_offset);
 
 void qemu_ram_munmap(int fd, void *ptr, size_t size);
 
diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c
index XXXXXXX..XXXXXXX 100644
--- a/backends/hostmem-memfd.c
+++ b/backends/hostmem-memfd.c
@@ -XXX,XX +XXX,XX @@ memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
     name = host_memory_backend_get_name(backend);
     memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend),
                                    name, backend->size,
-                                   backend->share, fd, errp);
+                                   backend->share, fd, 0, errp);
     g_free(name);
 }
 
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -XXX,XX +XXX,XX @@ static void process_msg_shmem(IVShmemState *s, int fd, Error **errp)
 
     /* mmap the region and map into the BAR2 */
     memory_region_init_ram_from_fd(&s->server_bar2, OBJECT(s),
-                                   "ivshmem.bar2", size, true, fd, &local_err);
+                                   "ivshmem.bar2", size, true, fd, 0,
+                                   &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return;
diff --git a/softmmu/memory.c b/softmmu/memory.c
index XXXXXXX..XXXXXXX 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -XXX,XX +XXX,XX @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,
                                     uint64_t size,
                                     bool share,
                                     int fd,
+                                    ram_addr_t offset,
                                     Error **errp)
 {
     Error *err = NULL;
@@ -XXX,XX +XXX,XX @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,
     mr->destructor = memory_region_destructor_ram;
     mr->ram_block = qemu_ram_alloc_from_fd(size, mr,
                                            share ? RAM_SHARED : 0,
-                                           fd, false, &err);
+                                           fd, offset, false, &err);
     if (err) {
         mr->size = int128_zero();
         object_unparent(OBJECT(mr));
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index XXXXXXX..XXXXXXX 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -XXX,XX +XXX,XX @@ static void *file_ram_alloc(RAMBlock *block,
                             int fd,
                             bool readonly,
                             bool truncate,
+                            off_t offset,
                             Error **errp)
 {
     void *area;
@@ -XXX,XX +XXX,XX @@ static void *file_ram_alloc(RAMBlock *block,
     }
 
     area = qemu_ram_mmap(fd, memory, block->mr->align, readonly,
-                         block->flags & RAM_SHARED, block->flags & RAM_PMEM);
+                         block->flags & RAM_SHARED, block->flags & RAM_PMEM,
+                         offset);
     if (area == MAP_FAILED) {
         error_setg_errno(errp, errno,
                          "unable to map backing store for guest RAM");
@@ -XXX,XX +XXX,XX @@ static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared)
 
 #ifdef CONFIG_POSIX
 RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
-                                 uint32_t ram_flags, int fd, bool readonly,
-                                 Error **errp)
+                                 uint32_t ram_flags, int fd, off_t offset,
+                                 bool readonly, Error **errp)
 {
     RAMBlock *new_block;
     Error *local_err = NULL;
@@ -XXX,XX +XXX,XX @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
     new_block->max_length = size;
     new_block->flags = ram_flags;
     new_block->host = file_ram_alloc(new_block, size, fd, readonly,
-                                     !file_size, errp);
+                                     !file_size, offset, errp);
     if (!new_block->host) {
         g_free(new_block);
         return NULL;
@@ -XXX,XX +XXX,XX @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
         return NULL;
     }
 
-    block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, readonly, errp);
+    block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, 0, readonly, errp);
     if (!block) {
         if (created) {
             unlink(mem_path);
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index XXXXXXX..XXXXXXX 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -XXX,XX +XXX,XX @@ void *qemu_ram_mmap(int fd,
                     size_t align,
                     bool readonly,
                     bool shared,
-                    bool is_pmem)
+                    bool is_pmem,
+                    off_t map_offset)
 {
     int prot;
     int flags;
@@ -XXX,XX +XXX,XX @@ void *qemu_ram_mmap(int fd,
 
     prot = PROT_READ | (readonly ? 0 : PROT_WRITE);
 
-    ptr = mmap(guardptr + offset, size, prot, flags | map_sync_flags, fd, 0);
+    ptr = mmap(guardptr + offset, size, prot,
+               flags | map_sync_flags, fd, map_offset);
 
     if (ptr == MAP_FAILED && map_sync_flags) {
         if (errno == ENOTSUP) {
@@ -XXX,XX +XXX,XX @@ void *qemu_ram_mmap(int fd,
          * if map failed with MAP_SHARED_VALIDATE | MAP_SYNC,
          * we will remove these flags to handle compatibility.
          */
-        ptr = mmap(guardptr + offset, size, prot, flags, fd, 0);
+        ptr = mmap(guardptr + offset, size, prot, flags, fd, map_offset);
     }
 
     if (ptr == MAP_FAILED) {
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index XXXXXXX..XXXXXXX 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -XXX,XX +XXX,XX @@ void *qemu_memalign(size_t alignment, size_t size)
 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
 {
     size_t align = QEMU_VMALLOC_ALIGN;
-    void *ptr = qemu_ram_mmap(-1, size, align, false, shared, false);
+    void *ptr = qemu_ram_mmap(-1, size, align, false, shared, false, 0);
 
     if (ptr == MAP_FAILED) {
         return NULL;
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

Add configuration options to enable or disable multiprocess QEMU code

diff --git a/configure b/configure
index XXXXXXX..XXXXXXX 100755
--- a/configure
+++ b/configure
@@ -XXX,XX +XXX,XX @@ skip_meson=no
 gettext="auto"
 fuse="auto"
 fuse_lseek="auto"
+multiprocess="no"
 
 malloc_trim="auto"
 
@@ -XXX,XX +XXX,XX @@ Linux)
   linux="yes"
   linux_user="yes"
   vhost_user=${default_feature:-yes}
+  multiprocess=${default_feature:-yes}
 ;;
 esac
 
@@ -XXX,XX +XXX,XX @@ for opt do
   ;;
   --disable-fuse-lseek) fuse_lseek="disabled"
   ;;
+  --enable-multiprocess) multiprocess="yes"
+  ;;
+  --disable-multiprocess) multiprocess="no"
+  ;;
   *)
       echo "ERROR: unknown option $opt"
       echo "Try '$0 --help' for more information"
@@ -XXX,XX +XXX,XX @@ disabled with --disable-FEATURE, default is enabled if available
   libdaxctl       libdaxctl support
   fuse            FUSE block device export
   fuse-lseek      SEEK_HOLE/SEEK_DATA support for FUSE exports
+  multiprocess    Multiprocess QEMU support
 
 NOTE: The object files are built at the place where configure is launched
 EOF
@@ -XXX,XX +XXX,XX @@ fi
 if test "$have_mlockall" = "yes" ; then
   echo "HAVE_MLOCKALL=y" >> $config_host_mak
 fi
+if test "$multiprocess" = "yes" ; then
+  echo "CONFIG_MULTIPROCESS_ALLOWED=y" >> $config_host_mak
+fi
 if test "$fuzzing" = "yes" ; then
   # If LIB_FUZZING_ENGINE is set, assume we are running on OSS-Fuzz, and the
   # needed CFLAGS have already been provided
diff --git a/meson.build b/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/meson.build
+++ b/meson.build
@@ -XXX,XX +XXX,XX @@ host_kconfig = \
   ('CONFIG_VHOST_KERNEL' in config_host ? ['CONFIG_VHOST_KERNEL=y'] : []) + \
   (have_virtfs ? ['CONFIG_VIRTFS=y'] : []) + \
   ('CONFIG_LINUX' in config_host ? ['CONFIG_LINUX=y'] : []) + \
-  ('CONFIG_PVRDMA' in config_host ? ['CONFIG_PVRDMA=y'] : [])
+  ('CONFIG_PVRDMA' in config_host ? ['CONFIG_PVRDMA=y'] : []) + \
+  ('CONFIG_MULTIPROCESS_ALLOWED' in config_host ? ['CONFIG_MULTIPROCESS_ALLOWED=y'] : [])
 
 ignored = [ 'TARGET_XML_FILES', 'TARGET_ABI_DIR', 'TARGET_ARCH' ]
 
@@ -XXX,XX +XXX,XX @@ summary_info += {'libpmem support':   config_host.has_key('CONFIG_LIBPMEM')}
 summary_info += {'libdaxctl support': config_host.has_key('CONFIG_LIBDAXCTL')}
 summary_info += {'libudev':           libudev.found()}
 summary_info += {'FUSE lseek':        fuse_lseek.found()}
+summary_info += {'Multiprocess QEMU': config_host.has_key('CONFIG_MULTIPROCESS_ALLOWED')}
 summary(summary_info, bool_yn: true, section: 'Dependencies')
 
 if not supported_cpus.contains(cpu)
diff --git a/Kconfig.host b/Kconfig.host
index XXXXXXX..XXXXXXX 100644
--- a/Kconfig.host
+++ b/Kconfig.host
@@ -XXX,XX +XXX,XX @@ config VIRTFS
 
 config PVRDMA
     bool
+
+config MULTIPROCESS_ALLOWED
+    bool
+    imply MULTIPROCESS
diff --git a/hw/Kconfig b/hw/Kconfig
index XXXXXXX..XXXXXXX 100644
--- a/hw/Kconfig
+++ b/hw/Kconfig
@@ -XXX,XX +XXX,XX @@ source pci-host/Kconfig
 source pcmcia/Kconfig
 source pci/Kconfig
 source rdma/Kconfig
+source remote/Kconfig
 source rtc/Kconfig
 source scsi/Kconfig
 source sd/Kconfig
diff --git a/hw/remote/Kconfig b/hw/remote/Kconfig
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/Kconfig
@@ -XXX,XX +XXX,XX @@
+config MULTIPROCESS
+    bool
+    depends on PCI && KVM
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

PCI host bridge is setup for the remote device process. It is
implemented using remote-pcihost object. It is an extension of the PCI
host bridge setup by QEMU.
Remote-pcihost configures a PCI bus which could be used by the remote
PCI device to latch on to.

[Added PCI_EXPRESS condition in hw/remote/Kconfig since remote-pcihost
needs PCIe. This solves "make check" failure on s390x. Fix suggested by
Philippe Mathieu-Daudé <philmd@redhat.com> and Thomas Huth
<thuth@redhat.com>.
--Stefan]

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS                  |  2 +
 include/hw/pci-host/remote.h | 29 ++++++++++++++
 hw/pci-host/remote.c         | 75 ++++++++++++++++++++++++++++++++++++
 hw/pci-host/Kconfig          |  3 ++
 hw/pci-host/meson.build      |  1 +
 hw/remote/Kconfig            |  3 +-
 6 files changed, 112 insertions(+), 1 deletion(-)
 create mode 100644 include/hw/pci-host/remote.h
 create mode 100644 hw/pci-host/remote.c

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ M: John G Johnson <john.g.johnson@oracle.com>
 S: Maintained
 F: docs/devel/multi-process.rst
 F: docs/system/multi-process.rst
+F: hw/pci-host/remote.c
+F: include/hw/pci-host/remote.h
 
 Build and test automation
 -------------------------
diff --git a/include/hw/pci-host/remote.h b/include/hw/pci-host/remote.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/include/hw/pci-host/remote.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * PCI Host for remote device
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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 REMOTE_PCIHOST_H
+#define REMOTE_PCIHOST_H
+
+#include "exec/memory.h"
+#include "hw/pci/pcie_host.h"
+
+#define TYPE_REMOTE_PCIHOST "remote-pcihost"
+OBJECT_DECLARE_SIMPLE_TYPE(RemotePCIHost, REMOTE_PCIHOST)
+
+struct RemotePCIHost {
+    /*< private >*/
+    PCIExpressHost parent_obj;
+    /*< public >*/
+
+    MemoryRegion *mr_pci_mem;
+    MemoryRegion *mr_sys_io;
+};
+
+#endif
diff --git a/hw/pci-host/remote.c b/hw/pci-host/remote.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/pci-host/remote.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Remote PCI host device
+ *
+ * Unlike PCI host devices that model physical hardware, the purpose
+ * of this PCI host is to host multi-process QEMU devices.
+ *
+ * Multi-process QEMU extends the PCI host of a QEMU machine into a
+ * remote process. Any PCI device attached to the remote process is
+ * visible in the QEMU guest. This allows existing QEMU device models
+ * to be reused in the remote process.
+ *
+ * This PCI host is purely a container for PCI devices. It's fake in the
+ * sense that the guest never sees this PCI host and has no way of
+ * accessing it. Its job is just to provide the environment that QEMU
+ * PCI device models need when running in a remote process.
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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-common.h"
+
+#include "hw/pci/pci.h"
+#include "hw/pci/pci_host.h"
+#include "hw/pci/pcie_host.h"
+#include "hw/qdev-properties.h"
+#include "hw/pci-host/remote.h"
+#include "exec/memory.h"
+
+static const char *remote_pcihost_root_bus_path(PCIHostState *host_bridge,
+                                                PCIBus *rootbus)
+{
+    return "0000:00";
+}
+
+static void remote_pcihost_realize(DeviceState *dev, Error **errp)
+{
+    PCIHostState *pci = PCI_HOST_BRIDGE(dev);
+    RemotePCIHost *s = REMOTE_PCIHOST(dev);
+
+    pci->bus = pci_root_bus_new(DEVICE(s), "remote-pci",
+                                s->mr_pci_mem, s->mr_sys_io,
+                                0, TYPE_PCIE_BUS);
+}
+
+static void remote_pcihost_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    PCIHostBridgeClass *hc = PCI_HOST_BRIDGE_CLASS(klass);
+
+    hc->root_bus_path = remote_pcihost_root_bus_path;
+    dc->realize = remote_pcihost_realize;
+
+    dc->user_creatable = false;
+    set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
+    dc->fw_name = "pci";
+}
+
+static const TypeInfo remote_pcihost_info = {
+    .name = TYPE_REMOTE_PCIHOST,
+    .parent = TYPE_PCIE_HOST_BRIDGE,
+    .instance_size = sizeof(RemotePCIHost),
+    .class_init = remote_pcihost_class_init,
+};
+
+static void remote_pcihost_register(void)
+{
+    type_register_static(&remote_pcihost_info);
+}
+
+type_init(remote_pcihost_register)
diff --git a/hw/pci-host/Kconfig b/hw/pci-host/Kconfig
index XXXXXXX..XXXXXXX 100644
--- a/hw/pci-host/Kconfig
+++ b/hw/pci-host/Kconfig
@@ -XXX,XX +XXX,XX @@ config PCI_POWERNV
     select PCI_EXPRESS
     select MSI_NONBROKEN
     select PCIE_PORT
+
+config REMOTE_PCIHOST
+    bool
diff --git a/hw/pci-host/meson.build b/hw/pci-host/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/pci-host/meson.build
+++ b/hw/pci-host/meson.build
@@ -XXX,XX +XXX,XX @@ pci_ss.add(when: 'CONFIG_PCI_EXPRESS_XILINX', if_true: files('xilinx-pcie.c'))
 pci_ss.add(when: 'CONFIG_PCI_I440FX', if_true: files('i440fx.c'))
 pci_ss.add(when: 'CONFIG_PCI_SABRE', if_true: files('sabre.c'))
 pci_ss.add(when: 'CONFIG_XEN_IGD_PASSTHROUGH', if_true: files('xen_igd_pt.c'))
+pci_ss.add(when: 'CONFIG_REMOTE_PCIHOST', if_true: files('remote.c'))
 
 # PPC devices
 pci_ss.add(when: 'CONFIG_PREP_PCI', if_true: files('prep.c'))
diff --git a/hw/remote/Kconfig b/hw/remote/Kconfig
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/Kconfig
+++ b/hw/remote/Kconfig
@@ -XXX,XX +XXX,XX @@
 config MULTIPROCESS
     bool
-    depends on PCI && KVM
+    depends on PCI && PCI_EXPRESS && KVM
+    select REMOTE_PCIHOST
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

x-remote-machine object sets up various subsystems of the remote
device process. Instantiate PCI host bridge object and initialize RAM, IO &
PCI memory regions.

Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: c537f38d17f90453ca610c6b70cf3480274e0ba1.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS                  |  2 ++
 include/hw/pci-host/remote.h |  1 +
 include/hw/remote/machine.h  | 27 ++++++++++++++
 hw/remote/machine.c          | 70 ++++++++++++++++++++++++++++++++++++
 hw/meson.build               |  1 +
 hw/remote/meson.build        |  5 +++
 6 files changed, 106 insertions(+)
 create mode 100644 include/hw/remote/machine.h
 create mode 100644 hw/remote/machine.c
 create mode 100644 hw/remote/meson.build

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ F: docs/devel/multi-process.rst
 F: docs/system/multi-process.rst
 F: hw/pci-host/remote.c
 F: include/hw/pci-host/remote.h
+F: hw/remote/machine.c
+F: include/hw/remote/machine.h
 
 Build and test automation
 -------------------------
diff --git a/include/hw/pci-host/remote.h b/include/hw/pci-host/remote.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/pci-host/remote.h
+++ b/include/hw/pci-host/remote.h
@@ -XXX,XX +XXX,XX @@ struct RemotePCIHost {
 
     MemoryRegion *mr_pci_mem;
     MemoryRegion *mr_sys_io;
+    MemoryRegion *mr_sys_mem;
 };
 
 #endif
diff --git a/include/hw/remote/machine.h b/include/hw/remote/machine.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/include/hw/remote/machine.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * Remote machine configuration
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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 REMOTE_MACHINE_H
+#define REMOTE_MACHINE_H
+
+#include "qom/object.h"
+#include "hw/boards.h"
+#include "hw/pci-host/remote.h"
+
+struct RemoteMachineState {
+    MachineState parent_obj;
+
+    RemotePCIHost *host;
+};
+
+#define TYPE_REMOTE_MACHINE "x-remote-machine"
+OBJECT_DECLARE_SIMPLE_TYPE(RemoteMachineState, REMOTE_MACHINE)
+
+#endif
diff --git a/hw/remote/machine.c b/hw/remote/machine.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/machine.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Machine for remote device
+ *
+ *  This machine type is used by the remote device process in multi-process
+ *  QEMU. QEMU device models depend on parent busses, interrupt controllers,
+ *  memory regions, etc. The remote machine type offers this environment so
+ *  that QEMU device models can be used as remote devices.
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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-common.h"
+
+#include "hw/remote/machine.h"
+#include "exec/address-spaces.h"
+#include "exec/memory.h"
+#include "qapi/error.h"
+
+static void remote_machine_init(MachineState *machine)
+{
+    MemoryRegion *system_memory, *system_io, *pci_memory;
+    RemoteMachineState *s = REMOTE_MACHINE(machine);
+    RemotePCIHost *rem_host;
+
+    system_memory = get_system_memory();
+    system_io = get_system_io();
+
+    pci_memory = g_new(MemoryRegion, 1);
+    memory_region_init(pci_memory, NULL, "pci", UINT64_MAX);
+
+    rem_host = REMOTE_PCIHOST(qdev_new(TYPE_REMOTE_PCIHOST));
+
+    rem_host->mr_pci_mem = pci_memory;
+    rem_host->mr_sys_mem = system_memory;
+    rem_host->mr_sys_io = system_io;
+
+    s->host = rem_host;
+
+    object_property_add_child(OBJECT(s), "remote-pcihost", OBJECT(rem_host));
+    memory_region_add_subregion_overlap(system_memory, 0x0, pci_memory, -1);
+
+    qdev_realize(DEVICE(rem_host), sysbus_get_default(), &error_fatal);
+}
+
+static void remote_machine_class_init(ObjectClass *oc, void *data)
+{
+    MachineClass *mc = MACHINE_CLASS(oc);
+
+    mc->init = remote_machine_init;
+    mc->desc = "Experimental remote machine";
+}
+
+static const TypeInfo remote_machine = {
+    .name = TYPE_REMOTE_MACHINE,
+    .parent = TYPE_MACHINE,
+    .instance_size = sizeof(RemoteMachineState),
+    .class_init = remote_machine_class_init,
+};
+
+static void remote_machine_register_types(void)
+{
+    type_register_static(&remote_machine);
+}
+
+type_init(remote_machine_register_types);
diff --git a/hw/meson.build b/hw/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/meson.build
+++ b/hw/meson.build
@@ -XXX,XX +XXX,XX @@ subdir('moxie')
 subdir('nios2')
 subdir('openrisc')
 subdir('ppc')
+subdir('remote')
 subdir('riscv')
 subdir('rx')
 subdir('s390x')
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/meson.build
@@ -XXX,XX +XXX,XX @@
+remote_ss = ss.source_set()
+
+remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('machine.c'))
+
+softmmu_ss.add_all(when: 'CONFIG_MULTIPROCESS', if_true: remote_ss)
-- 
2.29.2

From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

Adds qio_channel_writev_full_all() to transmit both data and FDs.
Refactors existing code to use this helper.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 480fbf1fe4152495d60596c9b665124549b426a5.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/io/channel.h | 25 +++++++++++++++++++++++++
 io/channel.c         | 15 ++++++++++++++-
 2 files changed, 39 insertions(+), 1 deletion(-)

From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

Adds qio_channel_readv_full_all_eof() and qio_channel_readv_full_all()
to read both data and FDs. Refactors existing code to use these helpers.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: b059c4cc0fb741e794d644c144cc21372cad877d.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/io/channel.h |  53 +++++++++++++++++++++++
 io/channel.c         | 101 ++++++++++++++++++++++++++++++++++---------
 2 files changed, 134 insertions(+), 20 deletions(-)

diff --git a/include/io/channel.h b/include/io/channel.h
index XXXXXXX..XXXXXXX 100644
--- a/include/io/channel.h
+++ b/include/io/channel.h
@@ -XXX,XX +XXX,XX @@ void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
                                     IOHandler *io_write,
                                     void *opaque);
 
+/**
+ * qio_channel_readv_full_all_eof:
+ * @ioc: the channel object
+ * @iov: the array of memory regions to read data to
+ * @niov: the length of the @iov array
+ * @fds: an array of file handles to read
+ * @nfds: number of file handles in @fds
+ * @errp: pointer to a NULL-initialized error object
+ *
+ *
+ * Performs same function as qio_channel_readv_all_eof.
+ * Additionally, attempts to read file descriptors shared
+ * over the channel. The function will wait for all
+ * requested data to be read, yielding from the current
+ * coroutine if required. data refers to both file
+ * descriptors and the iovs.
+ *
+ * Returns: 1 if all bytes were read, 0 if end-of-file
+ *          occurs without data, or -1 on error
+ */
+
+int qio_channel_readv_full_all_eof(QIOChannel *ioc,
+                                   const struct iovec *iov,
+                                   size_t niov,
+                                   int **fds, size_t *nfds,
+                                   Error **errp);
+
+/**
+ * qio_channel_readv_full_all:
+ * @ioc: the channel object
+ * @iov: the array of memory regions to read data to
+ * @niov: the length of the @iov array
+ * @fds: an array of file handles to read
+ * @nfds: number of file handles in @fds
+ * @errp: pointer to a NULL-initialized error object
+ *
+ *
+ * Performs same function as qio_channel_readv_all_eof.
+ * Additionally, attempts to read file descriptors shared
+ * over the channel. The function will wait for all
+ * requested data to be read, yielding from the current
+ * coroutine if required. data refers to both file
+ * descriptors and the iovs.
+ *
+ * Returns: 0 if all bytes were read, or -1 on error
+ */
+
+int qio_channel_readv_full_all(QIOChannel *ioc,
+                               const struct iovec *iov,
+                               size_t niov,
+                               int **fds, size_t *nfds,
+                               Error **errp);
+
 /**
  * qio_channel_writev_full_all:
  * @ioc: the channel object
diff --git a/io/channel.c b/io/channel.c
index XXXXXXX..XXXXXXX 100644
--- a/io/channel.c
+++ b/io/channel.c
@@ -XXX,XX +XXX,XX @@ int qio_channel_readv_all_eof(QIOChannel *ioc,
                               const struct iovec *iov,
                               size_t niov,
                               Error **errp)
+{
+    return qio_channel_readv_full_all_eof(ioc, iov, niov, NULL, NULL, errp);
+}
+
+int qio_channel_readv_all(QIOChannel *ioc,
+                          const struct iovec *iov,
+                          size_t niov,
+                          Error **errp)
+{
+    return qio_channel_readv_full_all(ioc, iov, niov, NULL, NULL, errp);
+}
+
+int qio_channel_readv_full_all_eof(QIOChannel *ioc,
+                                   const struct iovec *iov,
+                                   size_t niov,
+                                   int **fds, size_t *nfds,
+                                   Error **errp)
 {
     int ret = -1;
     struct iovec *local_iov = g_new(struct iovec, niov);
     struct iovec *local_iov_head = local_iov;
     unsigned int nlocal_iov = niov;
+    int **local_fds = fds;
+    size_t *local_nfds = nfds;
     bool partial = false;
 
+    if (nfds) {
+        *nfds = 0;
+    }
+
+    if (fds) {
+        *fds = NULL;
+    }
+
     nlocal_iov = iov_copy(local_iov, nlocal_iov,
                           iov, niov,
                           0, iov_size(iov, niov));
 
-    while (nlocal_iov > 0) {
+    while ((nlocal_iov > 0) || local_fds) {
         ssize_t len;
-        len = qio_channel_readv(ioc, local_iov, nlocal_iov, errp);
+        len = qio_channel_readv_full(ioc, local_iov, nlocal_iov, local_fds,
+                                     local_nfds, errp);
         if (len == QIO_CHANNEL_ERR_BLOCK) {
             if (qemu_in_coroutine()) {
                 qio_channel_yield(ioc, G_IO_IN);
@@ -XXX,XX +XXX,XX @@ int qio_channel_readv_all_eof(QIOChannel *ioc,
                 qio_channel_wait(ioc, G_IO_IN);
             }
             continue;
-        } else if (len < 0) {
-            goto cleanup;
-        } else if (len == 0) {
-            if (partial) {
-                error_setg(errp,
-                           "Unexpected end-of-file before all bytes were read");
-            } else {
+        }
+
+        if (len == 0) {
+            if (local_nfds && *local_nfds) {
+                /*
+                 * Got some FDs, but no data yet. This isn't an EOF
+                 * scenario (yet), so carry on to try to read data
+                 * on next loop iteration
+                 */
+                goto next_iter;
+            } else if (!partial) {
+                /* No fds and no data - EOF before any data read */
                 ret = 0;
+                goto cleanup;
+            } else {
+                len = -1;
+                error_setg(errp,
+                           "Unexpected end-of-file before all data were read");
+                /* Fallthrough into len < 0 handling */
+            }
+        }
+
+        if (len < 0) {
+            /* Close any FDs we previously received */
+            if (nfds && fds) {
+                size_t i;
+                for (i = 0; i < (*nfds); i++) {
+                    close((*fds)[i]);
+                }
+                g_free(*fds);
+                *fds = NULL;
+                *nfds = 0;
             }
             goto cleanup;
         }
 
+        if (nlocal_iov) {
+            iov_discard_front(&local_iov, &nlocal_iov, len);
+        }
+
+next_iter:
         partial = true;
-        iov_discard_front(&local_iov, &nlocal_iov, len);
+        local_fds = NULL;
+        local_nfds = NULL;
     }
 
     ret = 1;
@@ -XXX,XX +XXX,XX @@ int qio_channel_readv_all_eof(QIOChannel *ioc,
     return ret;
 }
 
-int qio_channel_readv_all(QIOChannel *ioc,
-                          const struct iovec *iov,
-                          size_t niov,
-                          Error **errp)
+int qio_channel_readv_full_all(QIOChannel *ioc,
+                               const struct iovec *iov,
+                               size_t niov,
+                               int **fds, size_t *nfds,
+                               Error **errp)
 {
-    int ret = qio_channel_readv_all_eof(ioc, iov, niov, errp);
+    int ret = qio_channel_readv_full_all_eof(ioc, iov, niov, fds, nfds, errp);
 
     if (ret == 0) {
-        ret = -1;
-        error_setg(errp,
-                   "Unexpected end-of-file before all bytes were read");
-    } else if (ret == 1) {
-        ret = 0;
+        error_prepend(errp,
+                      "Unexpected end-of-file before all data were read.");
+        return -1;
     }
+    if (ret == 1) {
+        return 0;
+    }
+
     return ret;
 }
 
-- 
2.29.2

From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

Defines MPQemuMsg, which is the message that is sent to the remote
process. This message is sent over QIOChannel and is used to
command the remote process to perform various tasks.
Define transmission functions used by proxy and by remote.

[Replace struct iovec send[2] = {0} with {} to make clang happy as
suggested by Peter Maydell <peter.maydell@linaro.org>.
--Stefan]

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS                     |   2 +
 meson.build                     |   1 +
 hw/remote/trace.h               |   1 +
 include/hw/remote/mpqemu-link.h |  63 ++++++++++
 include/sysemu/iothread.h       |   6 +
 hw/remote/mpqemu-link.c         | 205 ++++++++++++++++++++++++++++++++
 iothread.c                      |   6 +
 hw/remote/meson.build           |   1 +
 hw/remote/trace-events          |   4 +
 9 files changed, 289 insertions(+)
 create mode 100644 hw/remote/trace.h
 create mode 100644 include/hw/remote/mpqemu-link.h
 create mode 100644 hw/remote/mpqemu-link.c
 create mode 100644 hw/remote/trace-events

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ F: hw/pci-host/remote.c
 F: include/hw/pci-host/remote.h
 F: hw/remote/machine.c
 F: include/hw/remote/machine.h
+F: hw/remote/mpqemu-link.c
+F: include/hw/remote/mpqemu-link.h
 
 Build and test automation
 -------------------------
diff --git a/meson.build b/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/meson.build
+++ b/meson.build
@@ -XXX,XX +XXX,XX @@ if have_system
     'net',
     'softmmu',
     'ui',
+    'hw/remote',
   ]
 endif
 if have_system or have_user
diff --git a/hw/remote/trace.h b/hw/remote/trace.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/trace.h
@@ -0,0 +1 @@
+#include "trace/trace-hw_remote.h"
diff --git a/include/hw/remote/mpqemu-link.h b/include/hw/remote/mpqemu-link.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/include/hw/remote/mpqemu-link.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * Communication channel between QEMU and remote device process
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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 MPQEMU_LINK_H
+#define MPQEMU_LINK_H
+
+#include "qom/object.h"
+#include "qemu/thread.h"
+#include "io/channel.h"
+
+#define REMOTE_MAX_FDS 8
+
+#define MPQEMU_MSG_HDR_SIZE offsetof(MPQemuMsg, data.u64)
+
+/**
+ * MPQemuCmd:
+ *
+ * MPQemuCmd enum type to specify the command to be executed on the remote
+ * device.
+ *
+ * This uses a private protocol between QEMU and the remote process. vfio-user
+ * protocol would supersede this in the future.
+ *
+ */
+typedef enum {
+    MPQEMU_CMD_MAX,
+} MPQemuCmd;
+
+/**
+ * MPQemuMsg:
+ * @cmd: The remote command
+ * @size: Size of the data to be shared
+ * @data: Structured data
+ * @fds: File descriptors to be shared with remote device
+ *
+ * MPQemuMsg Format of the message sent to the remote device from QEMU.
+ *
+ */
+typedef struct {
+    int cmd;
+    size_t size;
+
+    union {
+        uint64_t u64;
+    } data;
+
+    int fds[REMOTE_MAX_FDS];
+    int num_fds;
+} MPQemuMsg;
+
+bool mpqemu_msg_send(MPQemuMsg *msg, QIOChannel *ioc, Error **errp);
+bool mpqemu_msg_recv(MPQemuMsg *msg, QIOChannel *ioc, Error **errp);
+
+bool mpqemu_msg_valid(MPQemuMsg *msg);
+
+#endif
diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
index XXXXXXX..XXXXXXX 100644
--- a/include/sysemu/iothread.h
+++ b/include/sysemu/iothread.h
@@ -XXX,XX +XXX,XX @@ IOThread *iothread_create(const char *id, Error **errp);
 void iothread_stop(IOThread *iothread);
 void iothread_destroy(IOThread *iothread);
 
+/*
+ * Returns true if executing withing IOThread context,
+ * false otherwise.
+ */
+bool qemu_in_iothread(void);
+
 #endif /* IOTHREAD_H */
diff --git a/hw/remote/mpqemu-link.c b/hw/remote/mpqemu-link.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/mpqemu-link.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Communication channel between QEMU and remote device process
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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-common.h"
+
+#include "qemu/module.h"
+#include "hw/remote/mpqemu-link.h"
+#include "qapi/error.h"
+#include "qemu/iov.h"
+#include "qemu/error-report.h"
+#include "qemu/main-loop.h"
+#include "io/channel.h"
+#include "sysemu/iothread.h"
+#include "trace.h"
+
+/*
+ * Send message over the ioc QIOChannel.
+ * This function is safe to call from:
+ * - main loop in co-routine context. Will block the main loop if not in
+ *   co-routine context;
+ * - vCPU thread with no co-routine context and if the channel is not part
+ *   of the main loop handling;
+ * - IOThread within co-routine context, outside of co-routine context
+ *   will block IOThread;
+ * Returns true if no errors were encountered, false otherwise.
+ */
+bool mpqemu_msg_send(MPQemuMsg *msg, QIOChannel *ioc, Error **errp)
+{
+    ERRP_GUARD();
+    bool iolock = qemu_mutex_iothread_locked();
+    bool iothread = qemu_in_iothread();
+    struct iovec send[2] = {};
+    int *fds = NULL;
+    size_t nfds = 0;
+    bool ret = false;
+
+    send[0].iov_base = msg;
+    send[0].iov_len = MPQEMU_MSG_HDR_SIZE;
+
+    send[1].iov_base = (void *)&msg->data;
+    send[1].iov_len = msg->size;
+
+    if (msg->num_fds) {
+        nfds = msg->num_fds;
+        fds = msg->fds;
+    }
+
+    /*
+     * Dont use in IOThread out of co-routine context as
+     * it will block IOThread.
+     */
+    assert(qemu_in_coroutine() || !iothread);
+
+    /*
+     * Skip unlocking/locking iothread lock when the IOThread is running
+     * in co-routine context. Co-routine context is asserted above
+     * for IOThread case.
+     * Also skip lock handling while in a co-routine in the main context.
+     */
+    if (iolock && !iothread && !qemu_in_coroutine()) {
+        qemu_mutex_unlock_iothread();
+    }
+
+    if (!qio_channel_writev_full_all(ioc, send, G_N_ELEMENTS(send),
+                                    fds, nfds, errp)) {
+        ret = true;
+    } else {
+        trace_mpqemu_send_io_error(msg->cmd, msg->size, nfds);
+    }
+
+    if (iolock && !iothread && !qemu_in_coroutine()) {
+        /* See above comment why skip locking here. */
+        qemu_mutex_lock_iothread();
+    }
+
+    return ret;
+}
+
+/*
+ * Read message from the ioc QIOChannel.
+ * This function is safe to call from:
+ * - From main loop in co-routine context. Will block the main loop if not in
+ *   co-routine context;
+ * - From vCPU thread with no co-routine context and if the channel is not part
+ *   of the main loop handling;
+ * - From IOThread within co-routine context, outside of co-routine context
+ *   will block IOThread;
+ */
+static ssize_t mpqemu_read(QIOChannel *ioc, void *buf, size_t len, int **fds,
+                           size_t *nfds, Error **errp)
+{
+    ERRP_GUARD();
+    struct iovec iov = { .iov_base = buf, .iov_len = len };
+    bool iolock = qemu_mutex_iothread_locked();
+    bool iothread = qemu_in_iothread();
+    int ret = -1;
+
+    /*
+     * Dont use in IOThread out of co-routine context as
+     * it will block IOThread.
+     */
+    assert(qemu_in_coroutine() || !iothread);
+
+    if (iolock && !iothread && !qemu_in_coroutine()) {
+        qemu_mutex_unlock_iothread();
+    }
+
+    ret = qio_channel_readv_full_all_eof(ioc, &iov, 1, fds, nfds, errp);
+
+    if (iolock && !iothread && !qemu_in_coroutine()) {
+        qemu_mutex_lock_iothread();
+    }
+
+    return (ret <= 0) ? ret : iov.iov_len;
+}
+
+bool mpqemu_msg_recv(MPQemuMsg *msg, QIOChannel *ioc, Error **errp)
+{
+    ERRP_GUARD();
+    g_autofree int *fds = NULL;
+    size_t nfds = 0;
+    ssize_t len;
+    bool ret = false;
+
+    len = mpqemu_read(ioc, msg, MPQEMU_MSG_HDR_SIZE, &fds, &nfds, errp);
+    if (len <= 0) {
+        goto fail;
+    } else if (len != MPQEMU_MSG_HDR_SIZE) {
+        error_setg(errp, "Message header corrupted");
+        goto fail;
+    }
+
+    if (msg->size > sizeof(msg->data)) {
+        error_setg(errp, "Invalid size for message");
+        goto fail;
+    }
+
+    if (!msg->size) {
+        goto copy_fds;
+    }
+
+    len = mpqemu_read(ioc, &msg->data, msg->size, NULL, NULL, errp);
+    if (len <= 0) {
+        goto fail;
+    }
+    if (len != msg->size) {
+        error_setg(errp, "Unable to read full message");
+        goto fail;
+    }
+
+copy_fds:
+    msg->num_fds = nfds;
+    if (nfds > G_N_ELEMENTS(msg->fds)) {
+        error_setg(errp,
+                   "Overflow error: received %zu fds, more than max of %d fds",
+                   nfds, REMOTE_MAX_FDS);
+        goto fail;
+    }
+    if (nfds) {
+        memcpy(msg->fds, fds, nfds * sizeof(int));
+    }
+
+    ret = true;
+
+fail:
+    if (*errp) {
+        trace_mpqemu_recv_io_error(msg->cmd, msg->size, nfds);
+    }
+    while (*errp && nfds) {
+        close(fds[nfds - 1]);
+        nfds--;
+    }
+
+    return ret;
+}
+
+bool mpqemu_msg_valid(MPQemuMsg *msg)
+{
+    if (msg->cmd >= MPQEMU_CMD_MAX && msg->cmd < 0) {
+        return false;
+    }
+
+    /* Verify FDs. */
+    if (msg->num_fds >= REMOTE_MAX_FDS) {
+        return false;
+    }
+
+    if (msg->num_fds > 0) {
+        for (int i = 0; i < msg->num_fds; i++) {
+            if (fcntl(msg->fds[i], F_GETFL) == -1) {
+                return false;
+            }
+        }
+    }
+
+    return true;
+}
diff --git a/iothread.c b/iothread.c
index XXXXXXX..XXXXXXX 100644
--- a/iothread.c
+++ b/iothread.c
@@ -XXX,XX +XXX,XX @@ IOThread *iothread_by_id(const char *id)
 {
     return IOTHREAD(object_resolve_path_type(id, TYPE_IOTHREAD, NULL));
 }
+
+bool qemu_in_iothread(void)
+{
+    return qemu_get_current_aio_context() == qemu_get_aio_context() ?
+                    false : true;
+}
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/meson.build
+++ b/hw/remote/meson.build
@@ -XXX,XX +XXX,XX @@
 remote_ss = ss.source_set()
 
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('machine.c'))
+remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('mpqemu-link.c'))
 
 softmmu_ss.add_all(when: 'CONFIG_MULTIPROCESS', if_true: remote_ss)
diff --git a/hw/remote/trace-events b/hw/remote/trace-events
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/trace-events
@@ -XXX,XX +XXX,XX @@
+# multi-process trace events
+
+mpqemu_send_io_error(int cmd, int size, int nfds) "send command %d size %d, %d file descriptors to remote process"
+mpqemu_recv_io_error(int cmd, int size, int nfds) "failed to receive %d size %d, %d file descriptors to remote process"
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

Initializes the message handler function in the remote process. It is
called whenever there's an event pending on QIOChannel that registers
this function.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 99d38d8b93753a6409ac2340e858858cda59ab1b.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS                 |  1 +
 include/hw/remote/machine.h |  9 ++++++
 hw/remote/message.c         | 57 +++++++++++++++++++++++++++++++++++++
 hw/remote/meson.build       |  1 +
 4 files changed, 68 insertions(+)
 create mode 100644 hw/remote/message.c

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ F: hw/remote/machine.c
 F: include/hw/remote/machine.h
 F: hw/remote/mpqemu-link.c
 F: include/hw/remote/mpqemu-link.h
+F: hw/remote/message.c
 
 Build and test automation
 -------------------------
diff --git a/include/hw/remote/machine.h b/include/hw/remote/machine.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/remote/machine.h
+++ b/include/hw/remote/machine.h
@@ -XXX,XX +XXX,XX @@
 #include "qom/object.h"
 #include "hw/boards.h"
 #include "hw/pci-host/remote.h"
+#include "io/channel.h"
 
 struct RemoteMachineState {
     MachineState parent_obj;
@@ -XXX,XX +XXX,XX @@ struct RemoteMachineState {
     RemotePCIHost *host;
 };
 
+/* Used to pass to co-routine device and ioc. */
+typedef struct RemoteCommDev {
+    PCIDevice *dev;
+    QIOChannel *ioc;
+} RemoteCommDev;
+
 #define TYPE_REMOTE_MACHINE "x-remote-machine"
 OBJECT_DECLARE_SIMPLE_TYPE(RemoteMachineState, REMOTE_MACHINE)
 
+void coroutine_fn mpqemu_remote_msg_loop_co(void *data);
+
 #endif
diff --git a/hw/remote/message.c b/hw/remote/message.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/message.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Copyright © 2020, 2021 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL-v2, version 2 or later.
+ *
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+
+#include "hw/remote/machine.h"
+#include "io/channel.h"
+#include "hw/remote/mpqemu-link.h"
+#include "qapi/error.h"
+#include "sysemu/runstate.h"
+
+void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
+{
+    g_autofree RemoteCommDev *com = (RemoteCommDev *)data;
+    PCIDevice *pci_dev = NULL;
+    Error *local_err = NULL;
+
+    assert(com->ioc);
+
+    pci_dev = com->dev;
+    for (; !local_err;) {
+        MPQemuMsg msg = {0};
+
+        if (!mpqemu_msg_recv(&msg, com->ioc, &local_err)) {
+            break;
+        }
+
+        if (!mpqemu_msg_valid(&msg)) {
+            error_setg(&local_err, "Received invalid message from proxy"
+                                   "in remote process pid="FMT_pid"",
+                                   getpid());
+            break;
+        }
+
+        switch (msg.cmd) {
+        default:
+            error_setg(&local_err,
+                       "Unknown command (%d) received for device %s"
+                       " (pid="FMT_pid")",
+                       msg.cmd, DEVICE(pci_dev)->id, getpid());
+        }
+    }
+
+    if (local_err) {
+        error_report_err(local_err);
+        qemu_system_shutdown_request(SHUTDOWN_CAUSE_HOST_ERROR);
+    } else {
+        qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
+    }
+}
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/meson.build
+++ b/hw/remote/meson.build
@@ -XXX,XX +XXX,XX @@ remote_ss = ss.source_set()
 
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('machine.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('mpqemu-link.c'))
+remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('message.c'))
 
 softmmu_ss.add_all(when: 'CONFIG_MULTIPROCESS', if_true: remote_ss)
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

Associate the file descriptor for a PCIDevice in remote process with
DeviceState object.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: f405a2ed5d7518b87bea7c59cfdf334d67e5ee51.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS            |   1 +
 hw/remote/remote-obj.c | 203 +++++++++++++++++++++++++++++++++++++++++
 hw/remote/meson.build  |   1 +
 3 files changed, 205 insertions(+)
 create mode 100644 hw/remote/remote-obj.c

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ F: include/hw/remote/machine.h
 F: hw/remote/mpqemu-link.c
 F: include/hw/remote/mpqemu-link.h
 F: hw/remote/message.c
+F: hw/remote/remote-obj.c
 
 Build and test automation
 -------------------------
diff --git a/hw/remote/remote-obj.c b/hw/remote/remote-obj.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/remote-obj.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Copyright © 2020, 2021 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL-v2, version 2 or later.
+ *
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+
+#include "qemu/error-report.h"
+#include "qemu/notify.h"
+#include "qom/object_interfaces.h"
+#include "hw/qdev-core.h"
+#include "io/channel.h"
+#include "hw/qdev-core.h"
+#include "hw/remote/machine.h"
+#include "io/channel-util.h"
+#include "qapi/error.h"
+#include "sysemu/sysemu.h"
+#include "hw/pci/pci.h"
+#include "qemu/sockets.h"
+#include "monitor/monitor.h"
+
+#define TYPE_REMOTE_OBJECT "x-remote-object"
+OBJECT_DECLARE_TYPE(RemoteObject, RemoteObjectClass, REMOTE_OBJECT)
+
+struct RemoteObjectClass {
+    ObjectClass parent_class;
+
+    unsigned int nr_devs;
+    unsigned int max_devs;
+};
+
+struct RemoteObject {
+    /* private */
+    Object parent;
+
+    Notifier machine_done;
+
+    int32_t fd;
+    char *devid;
+
+    QIOChannel *ioc;
+
+    DeviceState *dev;
+    DeviceListener listener;
+};
+
+static void remote_object_set_fd(Object *obj, const char *str, Error **errp)
+{
+    RemoteObject *o = REMOTE_OBJECT(obj);
+    int fd = -1;
+
+    fd = monitor_fd_param(monitor_cur(), str, errp);
+    if (fd == -1) {
+        error_prepend(errp, "Could not parse remote object fd %s:", str);
+        return;
+    }
+
+    if (!fd_is_socket(fd)) {
+        error_setg(errp, "File descriptor '%s' is not a socket", str);
+        close(fd);
+        return;
+    }
+
+    o->fd = fd;
+}
+
+static void remote_object_set_devid(Object *obj, const char *str, Error **errp)
+{
+    RemoteObject *o = REMOTE_OBJECT(obj);
+
+    g_free(o->devid);
+
+    o->devid = g_strdup(str);
+}
+
+static void remote_object_unrealize_listener(DeviceListener *listener,
+                                             DeviceState *dev)
+{
+    RemoteObject *o = container_of(listener, RemoteObject, listener);
+
+    if (o->dev == dev) {
+        object_unref(OBJECT(o));
+    }
+}
+
+static void remote_object_machine_done(Notifier *notifier, void *data)
+{
+    RemoteObject *o = container_of(notifier, RemoteObject, machine_done);
+    DeviceState *dev = NULL;
+    QIOChannel *ioc = NULL;
+    Coroutine *co = NULL;
+    RemoteCommDev *comdev = NULL;
+    Error *err = NULL;
+
+    dev = qdev_find_recursive(sysbus_get_default(), o->devid);
+    if (!dev || !object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
+        error_report("%s is not a PCI device", o->devid);
+        return;
+    }
+
+    ioc = qio_channel_new_fd(o->fd, &err);
+    if (!ioc) {
+        error_report_err(err);
+        return;
+    }
+    qio_channel_set_blocking(ioc, false, NULL);
+
+    o->dev = dev;
+
+    o->listener.unrealize = remote_object_unrealize_listener;
+    device_listener_register(&o->listener);
+
+    /* co-routine should free this. */
+    comdev = g_new0(RemoteCommDev, 1);
+    *comdev = (RemoteCommDev) {
+        .ioc = ioc,
+        .dev = PCI_DEVICE(dev),
+    };
+
+    co = qemu_coroutine_create(mpqemu_remote_msg_loop_co, comdev);
+    qemu_coroutine_enter(co);
+}
+
+static void remote_object_init(Object *obj)
+{
+    RemoteObjectClass *k = REMOTE_OBJECT_GET_CLASS(obj);
+    RemoteObject *o = REMOTE_OBJECT(obj);
+
+    if (k->nr_devs >= k->max_devs) {
+        error_report("Reached maximum number of devices: %u", k->max_devs);
+        return;
+    }
+
+    o->ioc = NULL;
+    o->fd = -1;
+    o->devid = NULL;
+
+    k->nr_devs++;
+
+    o->machine_done.notify = remote_object_machine_done;
+    qemu_add_machine_init_done_notifier(&o->machine_done);
+}
+
+static void remote_object_finalize(Object *obj)
+{
+    RemoteObjectClass *k = REMOTE_OBJECT_GET_CLASS(obj);
+    RemoteObject *o = REMOTE_OBJECT(obj);
+
+    device_listener_unregister(&o->listener);
+
+    if (o->ioc) {
+        qio_channel_shutdown(o->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
+        qio_channel_close(o->ioc, NULL);
+    }
+
+    object_unref(OBJECT(o->ioc));
+
+    k->nr_devs--;
+    g_free(o->devid);
+}
+
+static void remote_object_class_init(ObjectClass *klass, void *data)
+{
+    RemoteObjectClass *k = REMOTE_OBJECT_CLASS(klass);
+
+    /*
+     * Limit number of supported devices to 1. This is done to avoid devices
+     * from one VM accessing the RAM of another VM. This is done until we
+     * start using separate address spaces for individual devices.
+     */
+    k->max_devs = 1;
+    k->nr_devs = 0;
+
+    object_class_property_add_str(klass, "fd", NULL, remote_object_set_fd);
+    object_class_property_add_str(klass, "devid", NULL,
+                                  remote_object_set_devid);
+}
+
+static const TypeInfo remote_object_info = {
+    .name = TYPE_REMOTE_OBJECT,
+    .parent = TYPE_OBJECT,
+    .instance_size = sizeof(RemoteObject),
+    .instance_init = remote_object_init,
+    .instance_finalize = remote_object_finalize,
+    .class_size = sizeof(RemoteObjectClass),
+    .class_init = remote_object_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_USER_CREATABLE },
+        { }
+    }
+};
+
+static void register_types(void)
+{
+    type_register_static(&remote_object_info);
+}
+
+type_init(register_types);
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/meson.build
+++ b/hw/remote/meson.build
@@ -XXX,XX +XXX,XX @@ remote_ss = ss.source_set()
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('machine.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('mpqemu-link.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('message.c'))
+remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('remote-obj.c'))
 
 softmmu_ss.add_all(when: 'CONFIG_MULTIPROCESS', if_true: remote_ss)
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

SyncSysMemMsg message format is defined. It is used to send
file descriptors of the RAM regions to remote device.
RAM on the remote device is configured with a set of file descriptors.
Old RAM regions are deleted and new regions, each with an fd, is
added to the RAM.

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 7d2d1831d812e85f681e7a8ab99e032cf4704689.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS                     |  2 +
 include/hw/remote/memory.h      | 19 ++++++++++
 include/hw/remote/mpqemu-link.h | 10 +++++
 hw/remote/memory.c              | 65 +++++++++++++++++++++++++++++++++
 hw/remote/mpqemu-link.c         | 11 ++++++
 hw/remote/meson.build           |  2 +
 6 files changed, 109 insertions(+)
 create mode 100644 include/hw/remote/memory.h
 create mode 100644 hw/remote/memory.c

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ F: hw/remote/mpqemu-link.c
 F: include/hw/remote/mpqemu-link.h
 F: hw/remote/message.c
 F: hw/remote/remote-obj.c
+F: include/hw/remote/memory.h
+F: hw/remote/memory.c
 
 Build and test automation
 -------------------------
diff --git a/include/hw/remote/memory.h b/include/hw/remote/memory.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/include/hw/remote/memory.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * Memory manager for remote device
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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 REMOTE_MEMORY_H
+#define REMOTE_MEMORY_H
+
+#include "exec/hwaddr.h"
+#include "hw/remote/mpqemu-link.h"
+
+void remote_sysmem_reconfig(MPQemuMsg *msg, Error **errp);
+
+#endif
diff --git a/include/hw/remote/mpqemu-link.h b/include/hw/remote/mpqemu-link.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/remote/mpqemu-link.h
+++ b/include/hw/remote/mpqemu-link.h
@@ -XXX,XX +XXX,XX @@
 #include "qom/object.h"
 #include "qemu/thread.h"
 #include "io/channel.h"
+#include "exec/hwaddr.h"
 
 #define REMOTE_MAX_FDS 8
 
@@ -XXX,XX +XXX,XX @@
  *
  */
 typedef enum {
+    MPQEMU_CMD_SYNC_SYSMEM,
     MPQEMU_CMD_MAX,
 } MPQemuCmd;
 
+typedef struct {
+    hwaddr gpas[REMOTE_MAX_FDS];
+    uint64_t sizes[REMOTE_MAX_FDS];
+    off_t offsets[REMOTE_MAX_FDS];
+} SyncSysmemMsg;
+
 /**
  * MPQemuMsg:
  * @cmd: The remote command
@@ -XXX,XX +XXX,XX @@ typedef enum {
  * MPQemuMsg Format of the message sent to the remote device from QEMU.
  *
  */
+
 typedef struct {
     int cmd;
     size_t size;
 
     union {
         uint64_t u64;
+        SyncSysmemMsg sync_sysmem;
     } data;
 
     int fds[REMOTE_MAX_FDS];
diff --git a/hw/remote/memory.c b/hw/remote/memory.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/memory.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Memory manager for remote device
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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-common.h"
+
+#include "hw/remote/memory.h"
+#include "exec/address-spaces.h"
+#include "exec/ram_addr.h"
+#include "qapi/error.h"
+
+static void remote_sysmem_reset(void)
+{
+    MemoryRegion *sysmem, *subregion, *next;
+
+    sysmem = get_system_memory();
+
+    QTAILQ_FOREACH_SAFE(subregion, &sysmem->subregions, subregions_link, next) {
+        if (subregion->ram) {
+            memory_region_del_subregion(sysmem, subregion);
+            object_unparent(OBJECT(subregion));
+        }
+    }
+}
+
+void remote_sysmem_reconfig(MPQemuMsg *msg, Error **errp)
+{
+    ERRP_GUARD();
+    SyncSysmemMsg *sysmem_info = &msg->data.sync_sysmem;
+    MemoryRegion *sysmem, *subregion;
+    static unsigned int suffix;
+    int region;
+
+    sysmem = get_system_memory();
+
+    remote_sysmem_reset();
+
+    for (region = 0; region < msg->num_fds; region++) {
+        g_autofree char *name;
+        subregion = g_new(MemoryRegion, 1);
+        name = g_strdup_printf("remote-mem-%u", suffix++);
+        memory_region_init_ram_from_fd(subregion, NULL,
+                                       name, sysmem_info->sizes[region],
+                                       true, msg->fds[region],
+                                       sysmem_info->offsets[region],
+                                       errp);
+
+        if (*errp) {
+            g_free(subregion);
+            remote_sysmem_reset();
+            return;
+        }
+
+        memory_region_add_subregion(sysmem, sysmem_info->gpas[region],
+                                    subregion);
+
+    }
+}
diff --git a/hw/remote/mpqemu-link.c b/hw/remote/mpqemu-link.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/mpqemu-link.c
+++ b/hw/remote/mpqemu-link.c
@@ -XXX,XX +XXX,XX @@ bool mpqemu_msg_valid(MPQemuMsg *msg)
         }
     }
 
+     /* Verify message specific fields. */
+    switch (msg->cmd) {
+    case MPQEMU_CMD_SYNC_SYSMEM:
+        if (msg->num_fds == 0 || msg->size != sizeof(SyncSysmemMsg)) {
+            return false;
+        }
+        break;
+    default:
+        break;
+    }
+
     return true;
 }
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/meson.build
+++ b/hw/remote/meson.build
@@ -XXX,XX +XXX,XX @@ remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('mpqemu-link.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('message.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('remote-obj.c'))
 
+specific_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('memory.c'))
+
 softmmu_ss.add_all(when: 'CONFIG_MULTIPROCESS', if_true: remote_ss)
-- 
2.29.2

From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

Defines a PCI Device proxy object as a child of TYPE_PCI_DEVICE.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: b5186ebfedf8e557044d09a768846c59230ad3a7.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS               |  2 +
 include/hw/remote/proxy.h | 33 +++++++++++++
 hw/remote/proxy.c         | 99 +++++++++++++++++++++++++++++++++++++++
 hw/remote/meson.build     |  1 +
 4 files changed, 135 insertions(+)
 create mode 100644 include/hw/remote/proxy.h
 create mode 100644 hw/remote/proxy.c

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ F: hw/remote/message.c
 F: hw/remote/remote-obj.c
 F: include/hw/remote/memory.h
 F: hw/remote/memory.c
+F: hw/remote/proxy.c
+F: include/hw/remote/proxy.h
 
 Build and test automation
 -------------------------
diff --git a/include/hw/remote/proxy.h b/include/hw/remote/proxy.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/include/hw/remote/proxy.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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 PROXY_H
+#define PROXY_H
+
+#include "hw/pci/pci.h"
+#include "io/channel.h"
+
+#define TYPE_PCI_PROXY_DEV "x-pci-proxy-dev"
+OBJECT_DECLARE_SIMPLE_TYPE(PCIProxyDev, PCI_PROXY_DEV)
+
+struct PCIProxyDev {
+    PCIDevice parent_dev;
+    char *fd;
+
+    /*
+     * Mutex used to protect the QIOChannel fd from
+     * the concurrent access by the VCPUs since proxy
+     * blocks while awaiting for the replies from the
+     * process remote.
+     */
+    QemuMutex io_mutex;
+    QIOChannel *ioc;
+    Error *migration_blocker;
+};
+
+#endif /* PROXY_H */
diff --git a/hw/remote/proxy.c b/hw/remote/proxy.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/proxy.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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-common.h"
+
+#include "hw/remote/proxy.h"
+#include "hw/pci/pci.h"
+#include "qapi/error.h"
+#include "io/channel-util.h"
+#include "hw/qdev-properties.h"
+#include "monitor/monitor.h"
+#include "migration/blocker.h"
+#include "qemu/sockets.h"
+
+static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
+{
+    ERRP_GUARD();
+    PCIProxyDev *dev = PCI_PROXY_DEV(device);
+    int fd;
+
+    if (!dev->fd) {
+        error_setg(errp, "fd parameter not specified for %s",
+                   DEVICE(device)->id);
+        return;
+    }
+
+    fd = monitor_fd_param(monitor_cur(), dev->fd, errp);
+    if (fd == -1) {
+        error_prepend(errp, "proxy: unable to parse fd %s: ", dev->fd);
+        return;
+    }
+
+    if (!fd_is_socket(fd)) {
+        error_setg(errp, "proxy: fd %d is not a socket", fd);
+        close(fd);
+        return;
+    }
+
+    dev->ioc = qio_channel_new_fd(fd, errp);
+
+    error_setg(&dev->migration_blocker, "%s does not support migration",
+               TYPE_PCI_PROXY_DEV);
+    migrate_add_blocker(dev->migration_blocker, errp);
+
+    qemu_mutex_init(&dev->io_mutex);
+    qio_channel_set_blocking(dev->ioc, true, NULL);
+}
+
+static void pci_proxy_dev_exit(PCIDevice *pdev)
+{
+    PCIProxyDev *dev = PCI_PROXY_DEV(pdev);
+
+    if (dev->ioc) {
+        qio_channel_close(dev->ioc, NULL);
+    }
+
+    migrate_del_blocker(dev->migration_blocker);
+
+    error_free(dev->migration_blocker);
+}
+
+static Property proxy_properties[] = {
+    DEFINE_PROP_STRING("fd", PCIProxyDev, fd),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void pci_proxy_dev_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+
+    k->realize = pci_proxy_dev_realize;
+    k->exit = pci_proxy_dev_exit;
+    device_class_set_props(dc, proxy_properties);
+}
+
+static const TypeInfo pci_proxy_dev_type_info = {
+    .name          = TYPE_PCI_PROXY_DEV,
+    .parent        = TYPE_PCI_DEVICE,
+    .instance_size = sizeof(PCIProxyDev),
+    .class_init    = pci_proxy_dev_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { INTERFACE_CONVENTIONAL_PCI_DEVICE },
+        { },
+    },
+};
+
+static void pci_proxy_dev_register_types(void)
+{
+    type_register_static(&pci_proxy_dev_type_info);
+}
+
+type_init(pci_proxy_dev_register_types)
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/meson.build
+++ b/hw/remote/meson.build
@@ -XXX,XX +XXX,XX @@ remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('machine.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('mpqemu-link.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('message.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('remote-obj.c'))
+remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('proxy.c'))
 
 specific_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('memory.c'))
 
-- 
2.29.2

From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: d54edb4176361eed86b903e8f27058363b6c83b3.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/hw/remote/mpqemu-link.h |  4 ++++
 hw/remote/mpqemu-link.c         | 34 +++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/include/hw/remote/mpqemu-link.h b/include/hw/remote/mpqemu-link.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/remote/mpqemu-link.h
+++ b/include/hw/remote/mpqemu-link.h
@@ -XXX,XX +XXX,XX @@
 #include "qemu/thread.h"
 #include "io/channel.h"
 #include "exec/hwaddr.h"
+#include "io/channel-socket.h"
+#include "hw/remote/proxy.h"
 
 #define REMOTE_MAX_FDS 8
 
@@ -XXX,XX +XXX,XX @@ typedef struct {
 bool mpqemu_msg_send(MPQemuMsg *msg, QIOChannel *ioc, Error **errp);
 bool mpqemu_msg_recv(MPQemuMsg *msg, QIOChannel *ioc, Error **errp);
 
+uint64_t mpqemu_msg_send_and_await_reply(MPQemuMsg *msg, PCIProxyDev *pdev,
+                                         Error **errp);
 bool mpqemu_msg_valid(MPQemuMsg *msg);
 
 #endif
diff --git a/hw/remote/mpqemu-link.c b/hw/remote/mpqemu-link.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/mpqemu-link.c
+++ b/hw/remote/mpqemu-link.c
@@ -XXX,XX +XXX,XX @@ fail:
     return ret;
 }
 
+/*
+ * Send msg and wait for a reply with command code RET_MSG.
+ * Returns the message received of size u64 or UINT64_MAX
+ * on error.
+ * Called from VCPU thread in non-coroutine context.
+ * Used by the Proxy object to communicate to remote processes.
+ */
+uint64_t mpqemu_msg_send_and_await_reply(MPQemuMsg *msg, PCIProxyDev *pdev,
+                                         Error **errp)
+{
+    ERRP_GUARD();
+    MPQemuMsg msg_reply = {0};
+    uint64_t ret = UINT64_MAX;
+
+    assert(!qemu_in_coroutine());
+
+    QEMU_LOCK_GUARD(&pdev->io_mutex);
+    if (!mpqemu_msg_send(msg, pdev->ioc, errp)) {
+        return ret;
+    }
+
+    if (!mpqemu_msg_recv(&msg_reply, pdev->ioc, errp)) {
+        return ret;
+    }
+
+    if (!mpqemu_msg_valid(&msg_reply)) {
+        error_setg(errp, "ERROR: Invalid reply received for command %d",
+                         msg->cmd);
+        return ret;
+    }
+
+    return msg_reply.data.u64;
+}
+
 bool mpqemu_msg_valid(MPQemuMsg *msg)
 {
     if (msg->cmd >= MPQEMU_CMD_MAX && msg->cmd < 0) {
-- 
2.29.2

From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

The Proxy Object sends the PCI config space accesses as messages
to the remote process over the communication channel

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: d3c94f4618813234655356c60e6f0d0362ff42d6.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/hw/remote/mpqemu-link.h | 10 ++++++
 hw/remote/message.c             | 60 +++++++++++++++++++++++++++++++++
 hw/remote/mpqemu-link.c         |  8 ++++-
 hw/remote/proxy.c               | 55 ++++++++++++++++++++++++++++++
 4 files changed, 132 insertions(+), 1 deletion(-)

diff --git a/include/hw/remote/mpqemu-link.h b/include/hw/remote/mpqemu-link.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/remote/mpqemu-link.h
+++ b/include/hw/remote/mpqemu-link.h
@@ -XXX,XX +XXX,XX @@
  */
 typedef enum {
     MPQEMU_CMD_SYNC_SYSMEM,
+    MPQEMU_CMD_RET,
+    MPQEMU_CMD_PCI_CFGWRITE,
+    MPQEMU_CMD_PCI_CFGREAD,
     MPQEMU_CMD_MAX,
 } MPQemuCmd;
 
@@ -XXX,XX +XXX,XX @@ typedef struct {
     off_t offsets[REMOTE_MAX_FDS];
 } SyncSysmemMsg;
 
+typedef struct {
+    uint32_t addr;
+    uint32_t val;
+    int len;
+} PciConfDataMsg;
+
 /**
  * MPQemuMsg:
  * @cmd: The remote command
@@ -XXX,XX +XXX,XX @@ typedef struct {
 
     union {
         uint64_t u64;
+        PciConfDataMsg pci_conf_data;
         SyncSysmemMsg sync_sysmem;
     } data;
 
diff --git a/hw/remote/message.c b/hw/remote/message.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/message.c
+++ b/hw/remote/message.c
@@ -XXX,XX +XXX,XX @@
 #include "hw/remote/mpqemu-link.h"
 #include "qapi/error.h"
 #include "sysemu/runstate.h"
+#include "hw/pci/pci.h"
+
+static void process_config_write(QIOChannel *ioc, PCIDevice *dev,
+                                 MPQemuMsg *msg, Error **errp);
+static void process_config_read(QIOChannel *ioc, PCIDevice *dev,
+                                MPQemuMsg *msg, Error **errp);
 
 void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
 {
@@ -XXX,XX +XXX,XX @@ void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
         }
 
         switch (msg.cmd) {
+        case MPQEMU_CMD_PCI_CFGWRITE:
+            process_config_write(com->ioc, pci_dev, &msg, &local_err);
+            break;
+        case MPQEMU_CMD_PCI_CFGREAD:
+            process_config_read(com->ioc, pci_dev, &msg, &local_err);
+            break;
         default:
             error_setg(&local_err,
                        "Unknown command (%d) received for device %s"
@@ -XXX,XX +XXX,XX @@ void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
         qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
     }
 }
+
+static void process_config_write(QIOChannel *ioc, PCIDevice *dev,
+                                 MPQemuMsg *msg, Error **errp)
+{
+    ERRP_GUARD();
+    PciConfDataMsg *conf = (PciConfDataMsg *)&msg->data.pci_conf_data;
+    MPQemuMsg ret = { 0 };
+
+    if ((conf->addr + sizeof(conf->val)) > pci_config_size(dev)) {
+        error_setg(errp, "Bad address for PCI config write, pid "FMT_pid".",
+                   getpid());
+        ret.data.u64 = UINT64_MAX;
+    } else {
+        pci_default_write_config(dev, conf->addr, conf->val, conf->len);
+    }
+
+    ret.cmd = MPQEMU_CMD_RET;
+    ret.size = sizeof(ret.data.u64);
+
+    if (!mpqemu_msg_send(&ret, ioc, NULL)) {
+        error_prepend(errp, "Error returning code to proxy, pid "FMT_pid": ",
+                      getpid());
+    }
+}
+
+static void process_config_read(QIOChannel *ioc, PCIDevice *dev,
+                                MPQemuMsg *msg, Error **errp)
+{
+    ERRP_GUARD();
+    PciConfDataMsg *conf = (PciConfDataMsg *)&msg->data.pci_conf_data;
+    MPQemuMsg ret = { 0 };
+
+    if ((conf->addr + sizeof(conf->val)) > pci_config_size(dev)) {
+        error_setg(errp, "Bad address for PCI config read, pid "FMT_pid".",
+                   getpid());
+        ret.data.u64 = UINT64_MAX;
+    } else {
+        ret.data.u64 = pci_default_read_config(dev, conf->addr, conf->len);
+    }
+
+    ret.cmd = MPQEMU_CMD_RET;
+    ret.size = sizeof(ret.data.u64);
+
+    if (!mpqemu_msg_send(&ret, ioc, NULL)) {
+        error_prepend(errp, "Error returning code to proxy, pid "FMT_pid": ",
+                      getpid());
+    }
+}
diff --git a/hw/remote/mpqemu-link.c b/hw/remote/mpqemu-link.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/mpqemu-link.c
+++ b/hw/remote/mpqemu-link.c
@@ -XXX,XX +XXX,XX @@ uint64_t mpqemu_msg_send_and_await_reply(MPQemuMsg *msg, PCIProxyDev *pdev,
         return ret;
     }
 
-    if (!mpqemu_msg_valid(&msg_reply)) {
+    if (!mpqemu_msg_valid(&msg_reply) || msg_reply.cmd != MPQEMU_CMD_RET) {
         error_setg(errp, "ERROR: Invalid reply received for command %d",
                          msg->cmd);
         return ret;
@@ -XXX,XX +XXX,XX @@ bool mpqemu_msg_valid(MPQemuMsg *msg)
             return false;
         }
         break;
+    case MPQEMU_CMD_PCI_CFGWRITE:
+    case MPQEMU_CMD_PCI_CFGREAD:
+        if (msg->size != sizeof(PciConfDataMsg)) {
+            return false;
+        }
+        break;
     default:
         break;
     }
diff --git a/hw/remote/proxy.c b/hw/remote/proxy.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/proxy.c
+++ b/hw/remote/proxy.c
@@ -XXX,XX +XXX,XX @@
 #include "monitor/monitor.h"
 #include "migration/blocker.h"
 #include "qemu/sockets.h"
+#include "hw/remote/mpqemu-link.h"
+#include "qemu/error-report.h"
 
 static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
 {
@@ -XXX,XX +XXX,XX @@ static void pci_proxy_dev_exit(PCIDevice *pdev)
     error_free(dev->migration_blocker);
 }
 
+static void config_op_send(PCIProxyDev *pdev, uint32_t addr, uint32_t *val,
+                           int len, unsigned int op)
+{
+    MPQemuMsg msg = { 0 };
+    uint64_t ret = -EINVAL;
+    Error *local_err = NULL;
+
+    msg.cmd = op;
+    msg.data.pci_conf_data.addr = addr;
+    msg.data.pci_conf_data.val = (op == MPQEMU_CMD_PCI_CFGWRITE) ? *val : 0;
+    msg.data.pci_conf_data.len = len;
+    msg.size = sizeof(PciConfDataMsg);
+
+    ret = mpqemu_msg_send_and_await_reply(&msg, pdev, &local_err);
+    if (local_err) {
+        error_report_err(local_err);
+    }
+
+    if (ret == UINT64_MAX) {
+        error_report("Failed to perform PCI config %s operation",
+                     (op == MPQEMU_CMD_PCI_CFGREAD) ? "READ" : "WRITE");
+    }
+
+    if (op == MPQEMU_CMD_PCI_CFGREAD) {
+        *val = (uint32_t)ret;
+    }
+}
+
+static uint32_t pci_proxy_read_config(PCIDevice *d, uint32_t addr, int len)
+{
+    uint32_t val;
+
+    config_op_send(PCI_PROXY_DEV(d), addr, &val, len, MPQEMU_CMD_PCI_CFGREAD);
+
+    return val;
+}
+
+static void pci_proxy_write_config(PCIDevice *d, uint32_t addr, uint32_t val,
+                                   int len)
+{
+    /*
+     * Some of the functions access the copy of remote device's PCI config
+     * space which is cached in the proxy device. Therefore, maintain
+     * it updated.
+     */
+    pci_default_write_config(d, addr, val, len);
+
+    config_op_send(PCI_PROXY_DEV(d), addr, &val, len, MPQEMU_CMD_PCI_CFGWRITE);
+}
+
 static Property proxy_properties[] = {
     DEFINE_PROP_STRING("fd", PCIProxyDev, fd),
     DEFINE_PROP_END_OF_LIST(),
@@ -XXX,XX +XXX,XX @@ static void pci_proxy_dev_class_init(ObjectClass *klass, void *data)
 
     k->realize = pci_proxy_dev_realize;
     k->exit = pci_proxy_dev_exit;
+    k->config_read = pci_proxy_read_config;
+    k->config_write = pci_proxy_write_config;
+
     device_class_set_props(dc, proxy_properties);
 }
 
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

Proxy device object implements handler for PCI BAR writes and reads.
The handler uses BAR_WRITE/BAR_READ message to communicate to the
remote process with the BAR address and value to be written/read.
The remote process implements handler for BAR_WRITE/BAR_READ
message.

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: a8b76714a9688be5552c4c92d089bc9e8a4707ff.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/hw/remote/mpqemu-link.h | 10 ++++
 include/hw/remote/proxy.h       |  9 ++++
 hw/remote/message.c             | 83 +++++++++++++++++++++++++++++++++
 hw/remote/mpqemu-link.c         |  6 +++
 hw/remote/proxy.c               | 60 ++++++++++++++++++++++++
 5 files changed, 168 insertions(+)

diff --git a/include/hw/remote/mpqemu-link.h b/include/hw/remote/mpqemu-link.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/remote/mpqemu-link.h
+++ b/include/hw/remote/mpqemu-link.h
@@ -XXX,XX +XXX,XX @@ typedef enum {
     MPQEMU_CMD_RET,
     MPQEMU_CMD_PCI_CFGWRITE,
     MPQEMU_CMD_PCI_CFGREAD,
+    MPQEMU_CMD_BAR_WRITE,
+    MPQEMU_CMD_BAR_READ,
     MPQEMU_CMD_MAX,
 } MPQemuCmd;
 
@@ -XXX,XX +XXX,XX @@ typedef struct {
     int len;
 } PciConfDataMsg;
 
+typedef struct {
+    hwaddr addr;
+    uint64_t val;
+    unsigned size;
+    bool memory;
+} BarAccessMsg;
+
 /**
  * MPQemuMsg:
  * @cmd: The remote command
@@ -XXX,XX +XXX,XX @@ typedef struct {
         uint64_t u64;
         PciConfDataMsg pci_conf_data;
         SyncSysmemMsg sync_sysmem;
+        BarAccessMsg bar_access;
     } data;
 
     int fds[REMOTE_MAX_FDS];
diff --git a/include/hw/remote/proxy.h b/include/hw/remote/proxy.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/remote/proxy.h
+++ b/include/hw/remote/proxy.h
@@ -XXX,XX +XXX,XX @@
 #define TYPE_PCI_PROXY_DEV "x-pci-proxy-dev"
 OBJECT_DECLARE_SIMPLE_TYPE(PCIProxyDev, PCI_PROXY_DEV)
 
+typedef struct ProxyMemoryRegion {
+    PCIProxyDev *dev;
+    MemoryRegion mr;
+    bool memory;
+    bool present;
+    uint8_t type;
+} ProxyMemoryRegion;
+
 struct PCIProxyDev {
     PCIDevice parent_dev;
     char *fd;
@@ -XXX,XX +XXX,XX @@ struct PCIProxyDev {
     QemuMutex io_mutex;
     QIOChannel *ioc;
     Error *migration_blocker;
+    ProxyMemoryRegion region[PCI_NUM_REGIONS];
 };
 
 #endif /* PROXY_H */
diff --git a/hw/remote/message.c b/hw/remote/message.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/message.c
+++ b/hw/remote/message.c
@@ -XXX,XX +XXX,XX @@
 #include "qapi/error.h"
 #include "sysemu/runstate.h"
 #include "hw/pci/pci.h"
+#include "exec/memattrs.h"
 
 static void process_config_write(QIOChannel *ioc, PCIDevice *dev,
                                  MPQemuMsg *msg, Error **errp);
 static void process_config_read(QIOChannel *ioc, PCIDevice *dev,
                                 MPQemuMsg *msg, Error **errp);
+static void process_bar_write(QIOChannel *ioc, MPQemuMsg *msg, Error **errp);
+static void process_bar_read(QIOChannel *ioc, MPQemuMsg *msg, Error **errp);
 
 void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
 {
@@ -XXX,XX +XXX,XX @@ void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
         case MPQEMU_CMD_PCI_CFGREAD:
             process_config_read(com->ioc, pci_dev, &msg, &local_err);
             break;
+        case MPQEMU_CMD_BAR_WRITE:
+            process_bar_write(com->ioc, &msg, &local_err);
+            break;
+        case MPQEMU_CMD_BAR_READ:
+            process_bar_read(com->ioc, &msg, &local_err);
+            break;
         default:
             error_setg(&local_err,
                        "Unknown command (%d) received for device %s"
@@ -XXX,XX +XXX,XX @@ static void process_config_read(QIOChannel *ioc, PCIDevice *dev,
                       getpid());
     }
 }
+
+static void process_bar_write(QIOChannel *ioc, MPQemuMsg *msg, Error **errp)
+{
+    ERRP_GUARD();
+    BarAccessMsg *bar_access = &msg->data.bar_access;
+    AddressSpace *as =
+        bar_access->memory ? &address_space_memory : &address_space_io;
+    MPQemuMsg ret = { 0 };
+    MemTxResult res;
+    uint64_t val;
+
+    if (!is_power_of_2(bar_access->size) ||
+       (bar_access->size > sizeof(uint64_t))) {
+        ret.data.u64 = UINT64_MAX;
+        goto fail;
+    }
+
+    val = cpu_to_le64(bar_access->val);
+
+    res = address_space_rw(as, bar_access->addr, MEMTXATTRS_UNSPECIFIED,
+                           (void *)&val, bar_access->size, true);
+
+    if (res != MEMTX_OK) {
+        error_setg(errp, "Bad address %"PRIx64" for mem write, pid "FMT_pid".",
+                   bar_access->addr, getpid());
+        ret.data.u64 = -1;
+    }
+
+fail:
+    ret.cmd = MPQEMU_CMD_RET;
+    ret.size = sizeof(ret.data.u64);
+
+    if (!mpqemu_msg_send(&ret, ioc, NULL)) {
+        error_prepend(errp, "Error returning code to proxy, pid "FMT_pid": ",
+                      getpid());
+    }
+}
+
+static void process_bar_read(QIOChannel *ioc, MPQemuMsg *msg, Error **errp)
+{
+    ERRP_GUARD();
+    BarAccessMsg *bar_access = &msg->data.bar_access;
+    MPQemuMsg ret = { 0 };
+    AddressSpace *as;
+    MemTxResult res;
+    uint64_t val = 0;
+
+    as = bar_access->memory ? &address_space_memory : &address_space_io;
+
+    if (!is_power_of_2(bar_access->size) ||
+       (bar_access->size > sizeof(uint64_t))) {
+        val = UINT64_MAX;
+        goto fail;
+    }
+
+    res = address_space_rw(as, bar_access->addr, MEMTXATTRS_UNSPECIFIED,
+                           (void *)&val, bar_access->size, false);
+
+    if (res != MEMTX_OK) {
+        error_setg(errp, "Bad address %"PRIx64" for mem read, pid "FMT_pid".",
+                   bar_access->addr, getpid());
+        val = UINT64_MAX;
+    }
+
+fail:
+    ret.cmd = MPQEMU_CMD_RET;
+    ret.data.u64 = le64_to_cpu(val);
+    ret.size = sizeof(ret.data.u64);
+
+    if (!mpqemu_msg_send(&ret, ioc, NULL)) {
+        error_prepend(errp, "Error returning code to proxy, pid "FMT_pid": ",
+                      getpid());
+    }
+}
diff --git a/hw/remote/mpqemu-link.c b/hw/remote/mpqemu-link.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/mpqemu-link.c
+++ b/hw/remote/mpqemu-link.c
@@ -XXX,XX +XXX,XX @@ bool mpqemu_msg_valid(MPQemuMsg *msg)
             return false;
         }
         break;
+    case MPQEMU_CMD_BAR_WRITE:
+    case MPQEMU_CMD_BAR_READ:
+        if ((msg->size != sizeof(BarAccessMsg)) || (msg->num_fds != 0)) {
+            return false;
+        }
+        break;
     default:
         break;
     }
diff --git a/hw/remote/proxy.c b/hw/remote/proxy.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/proxy.c
+++ b/hw/remote/proxy.c
@@ -XXX,XX +XXX,XX @@ static void pci_proxy_dev_register_types(void)
 }
 
 type_init(pci_proxy_dev_register_types)
+
+static void send_bar_access_msg(PCIProxyDev *pdev, MemoryRegion *mr,
+                                bool write, hwaddr addr, uint64_t *val,
+                                unsigned size, bool memory)
+{
+    MPQemuMsg msg = { 0 };
+    long ret = -EINVAL;
+    Error *local_err = NULL;
+
+    msg.size = sizeof(BarAccessMsg);
+    msg.data.bar_access.addr = mr->addr + addr;
+    msg.data.bar_access.size = size;
+    msg.data.bar_access.memory = memory;
+
+    if (write) {
+        msg.cmd = MPQEMU_CMD_BAR_WRITE;
+        msg.data.bar_access.val = *val;
+    } else {
+        msg.cmd = MPQEMU_CMD_BAR_READ;
+    }
+
+    ret = mpqemu_msg_send_and_await_reply(&msg, pdev, &local_err);
+    if (local_err) {
+        error_report_err(local_err);
+    }
+
+    if (!write) {
+        *val = ret;
+    }
+}
+
+static void proxy_bar_write(void *opaque, hwaddr addr, uint64_t val,
+                            unsigned size)
+{
+    ProxyMemoryRegion *pmr = opaque;
+
+    send_bar_access_msg(pmr->dev, &pmr->mr, true, addr, &val, size,
+                        pmr->memory);
+}
+
+static uint64_t proxy_bar_read(void *opaque, hwaddr addr, unsigned size)
+{
+    ProxyMemoryRegion *pmr = opaque;
+    uint64_t val;
+
+    send_bar_access_msg(pmr->dev, &pmr->mr, false, addr, &val, size,
+                        pmr->memory);
+
+    return val;
+}
+
+const MemoryRegionOps proxy_mr_ops = {
+    .read = proxy_bar_read,
+    .write = proxy_bar_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 8,
+    },
+};
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

Add ProxyMemoryListener object which is used to keep the view of the RAM
in sync between QEMU and remote process.
A MemoryListener is registered for system-memory AddressSpace. The
listener sends SYNC_SYSMEM message to the remote process when memory
listener commits the changes to memory, the remote process receives
the message and processes it in the handler for SYNC_SYSMEM message.

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 04fe4e6a9ca90d4f11ab6f59be7652f5b086a071.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS                               |   2 +
 include/hw/remote/proxy-memory-listener.h |  28 +++
 include/hw/remote/proxy.h                 |   2 +
 hw/remote/message.c                       |   4 +
 hw/remote/proxy-memory-listener.c         | 227 ++++++++++++++++++++++
 hw/remote/proxy.c                         |   6 +
 hw/remote/meson.build                     |   1 +
 7 files changed, 270 insertions(+)
 create mode 100644 include/hw/remote/proxy-memory-listener.h
 create mode 100644 hw/remote/proxy-memory-listener.c

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ F: include/hw/remote/memory.h
 F: hw/remote/memory.c
 F: hw/remote/proxy.c
 F: include/hw/remote/proxy.h
+F: hw/remote/proxy-memory-listener.c
+F: include/hw/remote/proxy-memory-listener.h
 
 Build and test automation
 -------------------------
diff --git a/include/hw/remote/proxy-memory-listener.h b/include/hw/remote/proxy-memory-listener.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/include/hw/remote/proxy-memory-listener.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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 PROXY_MEMORY_LISTENER_H
+#define PROXY_MEMORY_LISTENER_H
+
+#include "exec/memory.h"
+#include "io/channel.h"
+
+typedef struct ProxyMemoryListener {
+    MemoryListener listener;
+
+    int n_mr_sections;
+    MemoryRegionSection *mr_sections;
+
+    QIOChannel *ioc;
+} ProxyMemoryListener;
+
+void proxy_memory_listener_configure(ProxyMemoryListener *proxy_listener,
+                                     QIOChannel *ioc);
+void proxy_memory_listener_deconfigure(ProxyMemoryListener *proxy_listener);
+
+#endif
diff --git a/include/hw/remote/proxy.h b/include/hw/remote/proxy.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/remote/proxy.h
+++ b/include/hw/remote/proxy.h
@@ -XXX,XX +XXX,XX @@
 
 #include "hw/pci/pci.h"
 #include "io/channel.h"
+#include "hw/remote/proxy-memory-listener.h"
 
 #define TYPE_PCI_PROXY_DEV "x-pci-proxy-dev"
 OBJECT_DECLARE_SIMPLE_TYPE(PCIProxyDev, PCI_PROXY_DEV)
@@ -XXX,XX +XXX,XX @@ struct PCIProxyDev {
     QemuMutex io_mutex;
     QIOChannel *ioc;
     Error *migration_blocker;
+    ProxyMemoryListener proxy_listener;
     ProxyMemoryRegion region[PCI_NUM_REGIONS];
 };
 
diff --git a/hw/remote/message.c b/hw/remote/message.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/message.c
+++ b/hw/remote/message.c
@@ -XXX,XX +XXX,XX @@
 #include "sysemu/runstate.h"
 #include "hw/pci/pci.h"
 #include "exec/memattrs.h"
+#include "hw/remote/memory.h"
 
 static void process_config_write(QIOChannel *ioc, PCIDevice *dev,
                                  MPQemuMsg *msg, Error **errp);
@@ -XXX,XX +XXX,XX @@ void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
         case MPQEMU_CMD_BAR_READ:
             process_bar_read(com->ioc, &msg, &local_err);
             break;
+        case MPQEMU_CMD_SYNC_SYSMEM:
+            remote_sysmem_reconfig(&msg, &local_err);
+            break;
         default:
             error_setg(&local_err,
                        "Unknown command (%d) received for device %s"
diff --git a/hw/remote/proxy-memory-listener.c b/hw/remote/proxy-memory-listener.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/proxy-memory-listener.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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-common.h"
+
+#include "qemu/compiler.h"
+#include "qemu/int128.h"
+#include "qemu/range.h"
+#include "exec/memory.h"
+#include "exec/cpu-common.h"
+#include "cpu.h"
+#include "exec/ram_addr.h"
+#include "exec/address-spaces.h"
+#include "qapi/error.h"
+#include "hw/remote/mpqemu-link.h"
+#include "hw/remote/proxy-memory-listener.h"
+
+/*
+ * TODO: get_fd_from_hostaddr(), proxy_mrs_can_merge() and
+ * proxy_memory_listener_commit() defined below perform tasks similar to the
+ * functions defined in vhost-user.c. These functions are good candidates
+ * for refactoring.
+ *
+ */
+
+static void proxy_memory_listener_reset(MemoryListener *listener)
+{
+    ProxyMemoryListener *proxy_listener = container_of(listener,
+                                                       ProxyMemoryListener,
+                                                       listener);
+    int mrs;
+
+    for (mrs = 0; mrs < proxy_listener->n_mr_sections; mrs++) {
+        memory_region_unref(proxy_listener->mr_sections[mrs].mr);
+    }
+
+    g_free(proxy_listener->mr_sections);
+    proxy_listener->mr_sections = NULL;
+    proxy_listener->n_mr_sections = 0;
+}
+
+static int get_fd_from_hostaddr(uint64_t host, ram_addr_t *offset)
+{
+    MemoryRegion *mr;
+    ram_addr_t off;
+
+    /**
+     * Assumes that the host address is a valid address as it's
+     * coming from the MemoryListener system. In the case host
+     * address is not valid, the following call would return
+     * the default subregion of "system_memory" region, and
+     * not NULL. So it's not possible to check for NULL here.
+     */
+    mr = memory_region_from_host((void *)(uintptr_t)host, &off);
+
+    if (offset) {
+        *offset = off;
+    }
+
+    return memory_region_get_fd(mr);
+}
+
+static bool proxy_mrs_can_merge(uint64_t host, uint64_t prev_host, size_t size)
+{
+    if (((prev_host + size) != host)) {
+        return false;
+    }
+
+    if (get_fd_from_hostaddr(host, NULL) !=
+            get_fd_from_hostaddr(prev_host, NULL)) {
+        return false;
+    }
+
+    return true;
+}
+
+static bool try_merge(ProxyMemoryListener *proxy_listener,
+                      MemoryRegionSection *section)
+{
+    uint64_t mrs_size, mrs_gpa, mrs_page;
+    MemoryRegionSection *prev_sec;
+    bool merged = false;
+    uintptr_t mrs_host;
+    RAMBlock *mrs_rb;
+
+    if (!proxy_listener->n_mr_sections) {
+        return false;
+    }
+
+    mrs_rb = section->mr->ram_block;
+    mrs_page = (uint64_t)qemu_ram_pagesize(mrs_rb);
+    mrs_size = int128_get64(section->size);
+    mrs_gpa = section->offset_within_address_space;
+    mrs_host = (uintptr_t)memory_region_get_ram_ptr(section->mr) +
+               section->offset_within_region;
+
+    if (get_fd_from_hostaddr(mrs_host, NULL) < 0) {
+        return true;
+    }
+
+    mrs_host = mrs_host & ~(mrs_page - 1);
+    mrs_gpa = mrs_gpa & ~(mrs_page - 1);
+    mrs_size = ROUND_UP(mrs_size, mrs_page);
+
+    prev_sec = proxy_listener->mr_sections +
+               (proxy_listener->n_mr_sections - 1);
+    uint64_t prev_gpa_start = prev_sec->offset_within_address_space;
+    uint64_t prev_size = int128_get64(prev_sec->size);
+    uint64_t prev_gpa_end   = range_get_last(prev_gpa_start, prev_size);
+    uint64_t prev_host_start =
+        (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr) +
+        prev_sec->offset_within_region;
+    uint64_t prev_host_end = range_get_last(prev_host_start, prev_size);
+
+    if (mrs_gpa <= (prev_gpa_end + 1)) {
+        g_assert(mrs_gpa > prev_gpa_start);
+
+        if ((section->mr == prev_sec->mr) &&
+            proxy_mrs_can_merge(mrs_host, prev_host_start,
+                                (mrs_gpa - prev_gpa_start))) {
+            uint64_t max_end = MAX(prev_host_end, mrs_host + mrs_size);
+            merged = true;
+            prev_sec->offset_within_address_space =
+                MIN(prev_gpa_start, mrs_gpa);
+            prev_sec->offset_within_region =
+                MIN(prev_host_start, mrs_host) -
+                (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr);
+            prev_sec->size = int128_make64(max_end - MIN(prev_host_start,
+                                                         mrs_host));
+        }
+    }
+
+    return merged;
+}
+
+static void proxy_memory_listener_region_addnop(MemoryListener *listener,
+                                                MemoryRegionSection *section)
+{
+    ProxyMemoryListener *proxy_listener = container_of(listener,
+                                                       ProxyMemoryListener,
+                                                       listener);
+
+    if (!memory_region_is_ram(section->mr) ||
+            memory_region_is_rom(section->mr)) {
+        return;
+    }
+
+    if (try_merge(proxy_listener, section)) {
+        return;
+    }
+
+    ++proxy_listener->n_mr_sections;
+    proxy_listener->mr_sections = g_renew(MemoryRegionSection,
+                                          proxy_listener->mr_sections,
+                                          proxy_listener->n_mr_sections);
+    proxy_listener->mr_sections[proxy_listener->n_mr_sections - 1] = *section;
+    proxy_listener->mr_sections[proxy_listener->n_mr_sections - 1].fv = NULL;
+    memory_region_ref(section->mr);
+}
+
+static void proxy_memory_listener_commit(MemoryListener *listener)
+{
+    ProxyMemoryListener *proxy_listener = container_of(listener,
+                                                       ProxyMemoryListener,
+                                                       listener);
+    MPQemuMsg msg;
+    MemoryRegionSection *section;
+    ram_addr_t offset;
+    uintptr_t host_addr;
+    int region;
+    Error *local_err = NULL;
+
+    memset(&msg, 0, sizeof(MPQemuMsg));
+
+    msg.cmd = MPQEMU_CMD_SYNC_SYSMEM;
+    msg.num_fds = proxy_listener->n_mr_sections;
+    msg.size = sizeof(SyncSysmemMsg);
+    if (msg.num_fds > REMOTE_MAX_FDS) {
+        error_report("Number of fds is more than %d", REMOTE_MAX_FDS);
+        return;
+    }
+
+    for (region = 0; region < proxy_listener->n_mr_sections; region++) {
+        section = &proxy_listener->mr_sections[region];
+        msg.data.sync_sysmem.gpas[region] =
+            section->offset_within_address_space;
+        msg.data.sync_sysmem.sizes[region] = int128_get64(section->size);
+        host_addr = (uintptr_t)memory_region_get_ram_ptr(section->mr) +
+                    section->offset_within_region;
+        msg.fds[region] = get_fd_from_hostaddr(host_addr, &offset);
+        msg.data.sync_sysmem.offsets[region] = offset;
+    }
+    if (!mpqemu_msg_send(&msg, proxy_listener->ioc, &local_err)) {
+        error_report_err(local_err);
+    }
+}
+
+void proxy_memory_listener_deconfigure(ProxyMemoryListener *proxy_listener)
+{
+    memory_listener_unregister(&proxy_listener->listener);
+
+    proxy_memory_listener_reset(&proxy_listener->listener);
+}
+
+void proxy_memory_listener_configure(ProxyMemoryListener *proxy_listener,
+                                     QIOChannel *ioc)
+{
+    proxy_listener->n_mr_sections = 0;
+    proxy_listener->mr_sections = NULL;
+
+    proxy_listener->ioc = ioc;
+
+    proxy_listener->listener.begin = proxy_memory_listener_reset;
+    proxy_listener->listener.commit = proxy_memory_listener_commit;
+    proxy_listener->listener.region_add = proxy_memory_listener_region_addnop;
+    proxy_listener->listener.region_nop = proxy_memory_listener_region_addnop;
+    proxy_listener->listener.priority = 10;
+
+    memory_listener_register(&proxy_listener->listener,
+                             &address_space_memory);
+}
diff --git a/hw/remote/proxy.c b/hw/remote/proxy.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/proxy.c
+++ b/hw/remote/proxy.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu/sockets.h"
 #include "hw/remote/mpqemu-link.h"
 #include "qemu/error-report.h"
+#include "hw/remote/proxy-memory-listener.h"
+#include "qom/object.h"
 
 static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
 {
@@ -XXX,XX +XXX,XX @@ static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
 
     qemu_mutex_init(&dev->io_mutex);
     qio_channel_set_blocking(dev->ioc, true, NULL);
+
+    proxy_memory_listener_configure(&dev->proxy_listener, dev->ioc);
 }
 
 static void pci_proxy_dev_exit(PCIDevice *pdev)
@@ -XXX,XX +XXX,XX @@ static void pci_proxy_dev_exit(PCIDevice *pdev)
     migrate_del_blocker(dev->migration_blocker);
 
     error_free(dev->migration_blocker);
+
+    proxy_memory_listener_deconfigure(&dev->proxy_listener);
 }
 
 static void config_op_send(PCIProxyDev *pdev, uint32_t addr, uint32_t *val,
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/meson.build
+++ b/hw/remote/meson.build
@@ -XXX,XX +XXX,XX @@ remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('remote-obj.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('proxy.c'))
 
 specific_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('memory.c'))
+specific_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('proxy-memory-listener.c'))
 
 softmmu_ss.add_all(when: 'CONFIG_MULTIPROCESS', if_true: remote_ss)
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

IOHUB object is added to manage PCI IRQs. It uses KVM_IRQFD
ioctl to create irqfd to injecting PCI interrupts to the guest.
IOHUB object forwards the irqfd to the remote process. Remote process
uses this fd to directly send interrupts to the guest, bypassing QEMU.

Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 51d5c3d54e28a68b002e3875c59599c9f5a424a1.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS                     |   2 +
 include/hw/pci/pci_ids.h        |   3 +
 include/hw/remote/iohub.h       |  42 +++++++++++
 include/hw/remote/machine.h     |   2 +
 include/hw/remote/mpqemu-link.h |   1 +
 include/hw/remote/proxy.h       |   4 ++
 hw/remote/iohub.c               | 119 ++++++++++++++++++++++++++++++++
 hw/remote/machine.c             |  10 +++
 hw/remote/message.c             |   4 ++
 hw/remote/mpqemu-link.c         |   5 ++
 hw/remote/proxy.c               |  56 +++++++++++++++
 hw/remote/meson.build           |   1 +
 12 files changed, 249 insertions(+)
 create mode 100644 include/hw/remote/iohub.h
 create mode 100644 hw/remote/iohub.c

diff --git a/MAINTAINERS b/MAINTAINERS
index XXXXXXX..XXXXXXX 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -XXX,XX +XXX,XX @@ F: hw/remote/proxy.c
 F: include/hw/remote/proxy.h
 F: hw/remote/proxy-memory-listener.c
 F: include/hw/remote/proxy-memory-listener.h
+F: hw/remote/iohub.c
+F: include/hw/remote/iohub.h
 
 Build and test automation
 -------------------------
diff --git a/include/hw/pci/pci_ids.h b/include/hw/pci/pci_ids.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/pci/pci_ids.h
+++ b/include/hw/pci/pci_ids.h
@@ -XXX,XX +XXX,XX @@
 #define PCI_DEVICE_ID_SUN_SIMBA          0x5000
 #define PCI_DEVICE_ID_SUN_SABRE          0xa000
 
+#define PCI_VENDOR_ID_ORACLE             0x108e
+#define PCI_DEVICE_ID_REMOTE_IOHUB       0xb000
+
 #define PCI_VENDOR_ID_CMD                0x1095
 #define PCI_DEVICE_ID_CMD_646            0x0646
 
diff --git a/include/hw/remote/iohub.h b/include/hw/remote/iohub.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/include/hw/remote/iohub.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * IO Hub for remote device
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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 REMOTE_IOHUB_H
+#define REMOTE_IOHUB_H
+
+#include "hw/pci/pci.h"
+#include "qemu/event_notifier.h"
+#include "qemu/thread-posix.h"
+#include "hw/remote/mpqemu-link.h"
+
+#define REMOTE_IOHUB_NB_PIRQS    PCI_DEVFN_MAX
+
+typedef struct ResampleToken {
+    void *iohub;
+    int pirq;
+} ResampleToken;
+
+typedef struct RemoteIOHubState {
+    PCIDevice d;
+    EventNotifier irqfds[REMOTE_IOHUB_NB_PIRQS];
+    EventNotifier resamplefds[REMOTE_IOHUB_NB_PIRQS];
+    unsigned int irq_level[REMOTE_IOHUB_NB_PIRQS];
+    ResampleToken token[REMOTE_IOHUB_NB_PIRQS];
+    QemuMutex irq_level_lock[REMOTE_IOHUB_NB_PIRQS];
+} RemoteIOHubState;
+
+int remote_iohub_map_irq(PCIDevice *pci_dev, int intx);
+void remote_iohub_set_irq(void *opaque, int pirq, int level);
+void process_set_irqfd_msg(PCIDevice *pci_dev, MPQemuMsg *msg);
+
+void remote_iohub_init(RemoteIOHubState *iohub);
+void remote_iohub_finalize(RemoteIOHubState *iohub);
+
+#endif
diff --git a/include/hw/remote/machine.h b/include/hw/remote/machine.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/remote/machine.h
+++ b/include/hw/remote/machine.h
@@ -XXX,XX +XXX,XX @@
 #include "hw/boards.h"
 #include "hw/pci-host/remote.h"
 #include "io/channel.h"
+#include "hw/remote/iohub.h"
 
 struct RemoteMachineState {
     MachineState parent_obj;
 
     RemotePCIHost *host;
+    RemoteIOHubState iohub;
 };
 
 /* Used to pass to co-routine device and ioc. */
diff --git a/include/hw/remote/mpqemu-link.h b/include/hw/remote/mpqemu-link.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/remote/mpqemu-link.h
+++ b/include/hw/remote/mpqemu-link.h
@@ -XXX,XX +XXX,XX @@ typedef enum {
     MPQEMU_CMD_PCI_CFGREAD,
     MPQEMU_CMD_BAR_WRITE,
     MPQEMU_CMD_BAR_READ,
+    MPQEMU_CMD_SET_IRQFD,
     MPQEMU_CMD_MAX,
 } MPQemuCmd;
 
diff --git a/include/hw/remote/proxy.h b/include/hw/remote/proxy.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/remote/proxy.h
+++ b/include/hw/remote/proxy.h
@@ -XXX,XX +XXX,XX @@
 #include "hw/pci/pci.h"
 #include "io/channel.h"
 #include "hw/remote/proxy-memory-listener.h"
+#include "qemu/event_notifier.h"
 
 #define TYPE_PCI_PROXY_DEV "x-pci-proxy-dev"
 OBJECT_DECLARE_SIMPLE_TYPE(PCIProxyDev, PCI_PROXY_DEV)
@@ -XXX,XX +XXX,XX @@ struct PCIProxyDev {
     QIOChannel *ioc;
     Error *migration_blocker;
     ProxyMemoryListener proxy_listener;
+    int virq;
+    EventNotifier intr;
+    EventNotifier resample;
     ProxyMemoryRegion region[PCI_NUM_REGIONS];
 };
 
diff --git a/hw/remote/iohub.c b/hw/remote/iohub.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/remote/iohub.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Remote IO Hub
+ *
+ * Copyright © 2018, 2021 Oracle and/or its affiliates.
+ *
+ * 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-common.h"
+
+#include "hw/pci/pci.h"
+#include "hw/pci/pci_ids.h"
+#include "hw/pci/pci_bus.h"
+#include "qemu/thread.h"
+#include "hw/boards.h"
+#include "hw/remote/machine.h"
+#include "hw/remote/iohub.h"
+#include "qemu/main-loop.h"
+
+void remote_iohub_init(RemoteIOHubState *iohub)
+{
+    int pirq;
+
+    memset(&iohub->irqfds, 0, sizeof(iohub->irqfds));
+    memset(&iohub->resamplefds, 0, sizeof(iohub->resamplefds));
+
+    for (pirq = 0; pirq < REMOTE_IOHUB_NB_PIRQS; pirq++) {
+        qemu_mutex_init(&iohub->irq_level_lock[pirq]);
+        iohub->irq_level[pirq] = 0;
+        event_notifier_init_fd(&iohub->irqfds[pirq], -1);
+        event_notifier_init_fd(&iohub->resamplefds[pirq], -1);
+    }
+}
+
+void remote_iohub_finalize(RemoteIOHubState *iohub)
+{
+    int pirq;
+
+    for (pirq = 0; pirq < REMOTE_IOHUB_NB_PIRQS; pirq++) {
+        qemu_set_fd_handler(event_notifier_get_fd(&iohub->resamplefds[pirq]),
+                            NULL, NULL, NULL);
+        event_notifier_cleanup(&iohub->irqfds[pirq]);
+        event_notifier_cleanup(&iohub->resamplefds[pirq]);
+        qemu_mutex_destroy(&iohub->irq_level_lock[pirq]);
+    }
+}
+
+int remote_iohub_map_irq(PCIDevice *pci_dev, int intx)
+{
+    return pci_dev->devfn;
+}
+
+void remote_iohub_set_irq(void *opaque, int pirq, int level)
+{
+    RemoteIOHubState *iohub = opaque;
+
+    assert(pirq >= 0);
+    assert(pirq < PCI_DEVFN_MAX);
+
+    QEMU_LOCK_GUARD(&iohub->irq_level_lock[pirq]);
+
+    if (level) {
+        if (++iohub->irq_level[pirq] == 1) {
+            event_notifier_set(&iohub->irqfds[pirq]);
+        }
+    } else if (iohub->irq_level[pirq] > 0) {
+        iohub->irq_level[pirq]--;
+    }
+}
+
+static void intr_resample_handler(void *opaque)
+{
+    ResampleToken *token = opaque;
+    RemoteIOHubState *iohub = token->iohub;
+    int pirq, s;
+
+    pirq = token->pirq;
+
+    s = event_notifier_test_and_clear(&iohub->resamplefds[pirq]);
+
+    assert(s >= 0);
+
+    QEMU_LOCK_GUARD(&iohub->irq_level_lock[pirq]);
+
+    if (iohub->irq_level[pirq]) {
+        event_notifier_set(&iohub->irqfds[pirq]);
+    }
+}
+
+void process_set_irqfd_msg(PCIDevice *pci_dev, MPQemuMsg *msg)
+{
+    RemoteMachineState *machine = REMOTE_MACHINE(current_machine);
+    RemoteIOHubState *iohub = &machine->iohub;
+    int pirq, intx;
+
+    intx = pci_get_byte(pci_dev->config + PCI_INTERRUPT_PIN) - 1;
+
+    pirq = remote_iohub_map_irq(pci_dev, intx);
+
+    if (event_notifier_get_fd(&iohub->irqfds[pirq]) != -1) {
+        qemu_set_fd_handler(event_notifier_get_fd(&iohub->resamplefds[pirq]),
+                            NULL, NULL, NULL);
+        event_notifier_cleanup(&iohub->irqfds[pirq]);
+        event_notifier_cleanup(&iohub->resamplefds[pirq]);
+        memset(&iohub->token[pirq], 0, sizeof(ResampleToken));
+    }
+
+    event_notifier_init_fd(&iohub->irqfds[pirq], msg->fds[0]);
+    event_notifier_init_fd(&iohub->resamplefds[pirq], msg->fds[1]);
+
+    iohub->token[pirq].iohub = iohub;
+    iohub->token[pirq].pirq = pirq;
+
+    qemu_set_fd_handler(msg->fds[1], intr_resample_handler, NULL,
+                        &iohub->token[pirq]);
+}
diff --git a/hw/remote/machine.c b/hw/remote/machine.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/machine.c
+++ b/hw/remote/machine.c
@@ -XXX,XX +XXX,XX @@
 #include "exec/address-spaces.h"
 #include "exec/memory.h"
 #include "qapi/error.h"
+#include "hw/pci/pci_host.h"
+#include "hw/remote/iohub.h"
 
 static void remote_machine_init(MachineState *machine)
 {
     MemoryRegion *system_memory, *system_io, *pci_memory;
     RemoteMachineState *s = REMOTE_MACHINE(machine);
     RemotePCIHost *rem_host;
+    PCIHostState *pci_host;
 
     system_memory = get_system_memory();
     system_io = get_system_io();
@@ -XXX,XX +XXX,XX @@ static void remote_machine_init(MachineState *machine)
     memory_region_add_subregion_overlap(system_memory, 0x0, pci_memory, -1);
 
     qdev_realize(DEVICE(rem_host), sysbus_get_default(), &error_fatal);
+
+    pci_host = PCI_HOST_BRIDGE(rem_host);
+
+    remote_iohub_init(&s->iohub);
+
+    pci_bus_irqs(pci_host->bus, remote_iohub_set_irq, remote_iohub_map_irq,
+                 &s->iohub, REMOTE_IOHUB_NB_PIRQS);
 }
 
 static void remote_machine_class_init(ObjectClass *oc, void *data)
diff --git a/hw/remote/message.c b/hw/remote/message.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/message.c
+++ b/hw/remote/message.c
@@ -XXX,XX +XXX,XX @@
 #include "hw/pci/pci.h"
 #include "exec/memattrs.h"
 #include "hw/remote/memory.h"
+#include "hw/remote/iohub.h"
 
 static void process_config_write(QIOChannel *ioc, PCIDevice *dev,
                                  MPQemuMsg *msg, Error **errp);
@@ -XXX,XX +XXX,XX @@ void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
         case MPQEMU_CMD_SYNC_SYSMEM:
             remote_sysmem_reconfig(&msg, &local_err);
             break;
+        case MPQEMU_CMD_SET_IRQFD:
+            process_set_irqfd_msg(pci_dev, &msg);
+            break;
         default:
             error_setg(&local_err,
                        "Unknown command (%d) received for device %s"
diff --git a/hw/remote/mpqemu-link.c b/hw/remote/mpqemu-link.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/mpqemu-link.c
+++ b/hw/remote/mpqemu-link.c
@@ -XXX,XX +XXX,XX @@ bool mpqemu_msg_valid(MPQemuMsg *msg)
             return false;
         }
         break;
+    case MPQEMU_CMD_SET_IRQFD:
+        if (msg->size || (msg->num_fds != 2)) {
+            return false;
+        }
+        break;
     default:
         break;
     }
diff --git a/hw/remote/proxy.c b/hw/remote/proxy.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/proxy.c
+++ b/hw/remote/proxy.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu/error-report.h"
 #include "hw/remote/proxy-memory-listener.h"
 #include "qom/object.h"
+#include "qemu/event_notifier.h"
+#include "sysemu/kvm.h"
+#include "util/event_notifier-posix.c"
+
+static void proxy_intx_update(PCIDevice *pci_dev)
+{
+    PCIProxyDev *dev = PCI_PROXY_DEV(pci_dev);
+    PCIINTxRoute route;
+    int pin = pci_get_byte(pci_dev->config + PCI_INTERRUPT_PIN) - 1;
+
+    if (dev->virq != -1) {
+        kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, &dev->intr, dev->virq);
+        dev->virq = -1;
+    }
+
+    route = pci_device_route_intx_to_irq(pci_dev, pin);
+
+    dev->virq = route.irq;
+
+    if (dev->virq != -1) {
+        kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, &dev->intr,
+                                           &dev->resample, dev->virq);
+    }
+}
+
+static void setup_irqfd(PCIProxyDev *dev)
+{
+    PCIDevice *pci_dev = PCI_DEVICE(dev);
+    MPQemuMsg msg;
+    Error *local_err = NULL;
+
+    event_notifier_init(&dev->intr, 0);
+    event_notifier_init(&dev->resample, 0);
+
+    memset(&msg, 0, sizeof(MPQemuMsg));
+    msg.cmd = MPQEMU_CMD_SET_IRQFD;
+    msg.num_fds = 2;
+    msg.fds[0] = event_notifier_get_fd(&dev->intr);
+    msg.fds[1] = event_notifier_get_fd(&dev->resample);
+    msg.size = 0;
+
+    if (!mpqemu_msg_send(&msg, dev->ioc, &local_err)) {
+        error_report_err(local_err);
+    }
+
+    dev->virq = -1;
+
+    proxy_intx_update(pci_dev);
+
+    pci_device_set_intx_routing_notifier(pci_dev, proxy_intx_update);
+}
 
 static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
 {
@@ -XXX,XX +XXX,XX @@ static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
     qio_channel_set_blocking(dev->ioc, true, NULL);
 
     proxy_memory_listener_configure(&dev->proxy_listener, dev->ioc);
+
+    setup_irqfd(dev);
 }
 
 static void pci_proxy_dev_exit(PCIDevice *pdev)
@@ -XXX,XX +XXX,XX @@ static void pci_proxy_dev_exit(PCIDevice *pdev)
     error_free(dev->migration_blocker);
 
     proxy_memory_listener_deconfigure(&dev->proxy_listener);
+
+    event_notifier_cleanup(&dev->intr);
+    event_notifier_cleanup(&dev->resample);
 }
 
 static void config_op_send(PCIProxyDev *pdev, uint32_t addr, uint32_t *val,
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/meson.build
+++ b/hw/remote/meson.build
@@ -XXX,XX +XXX,XX @@ remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('mpqemu-link.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('message.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('remote-obj.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('proxy.c'))
+remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('iohub.c'))
 
 specific_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('memory.c'))
 specific_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('proxy-memory-listener.c'))
-- 
2.29.2

From: Jagannathan Raman <jag.raman@oracle.com>

Retrieve PCI configuration info about the remote device and
configure the Proxy PCI object based on the returned information

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 85ee367bbb993aa23699b44cfedd83b4ea6d5221.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/remote/proxy.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/hw/remote/proxy.c b/hw/remote/proxy.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/remote/proxy.c
+++ b/hw/remote/proxy.c
@@ -XXX,XX +XXX,XX @@
 #include "sysemu/kvm.h"
 #include "util/event_notifier-posix.c"
 
+static void probe_pci_info(PCIDevice *dev, Error **errp);
+
 static void proxy_intx_update(PCIDevice *pci_dev)
 {
     PCIProxyDev *dev = PCI_PROXY_DEV(pci_dev);
@@ -XXX,XX +XXX,XX @@ static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
 {
     ERRP_GUARD();
     PCIProxyDev *dev = PCI_PROXY_DEV(device);
+    uint8_t *pci_conf = device->config;
     int fd;
 
     if (!dev->fd) {
@@ -XXX,XX +XXX,XX @@ static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
     qemu_mutex_init(&dev->io_mutex);
     qio_channel_set_blocking(dev->ioc, true, NULL);
 
+    pci_conf[PCI_LATENCY_TIMER] = 0xff;
+    pci_conf[PCI_INTERRUPT_PIN] = 0x01;
+
     proxy_memory_listener_configure(&dev->proxy_listener, dev->ioc);
 
     setup_irqfd(dev);
+
+    probe_pci_info(PCI_DEVICE(dev), errp);
 }
 
 static void pci_proxy_dev_exit(PCIDevice *pdev)
@@ -XXX,XX +XXX,XX @@ const MemoryRegionOps proxy_mr_ops = {
         .max_access_size = 8,
     },
 };
+
+static void probe_pci_info(PCIDevice *dev, Error **errp)
+{
+    PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(dev);
+    uint32_t orig_val, new_val, base_class, val;
+    PCIProxyDev *pdev = PCI_PROXY_DEV(dev);
+    DeviceClass *dc = DEVICE_CLASS(pc);
+    uint8_t type;
+    int i, size;
+
+    config_op_send(pdev, PCI_VENDOR_ID, &val, 2, MPQEMU_CMD_PCI_CFGREAD);
+    pc->vendor_id = (uint16_t)val;
+
+    config_op_send(pdev, PCI_DEVICE_ID, &val, 2, MPQEMU_CMD_PCI_CFGREAD);
+    pc->device_id = (uint16_t)val;
+
+    config_op_send(pdev, PCI_CLASS_DEVICE, &val, 2, MPQEMU_CMD_PCI_CFGREAD);
+    pc->class_id = (uint16_t)val;
+
+    config_op_send(pdev, PCI_SUBSYSTEM_ID, &val, 2, MPQEMU_CMD_PCI_CFGREAD);
+    pc->subsystem_id = (uint16_t)val;
+
+    base_class = pc->class_id >> 4;
+    switch (base_class) {
+    case PCI_BASE_CLASS_BRIDGE:
+        set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
+        break;
+    case PCI_BASE_CLASS_STORAGE:
+        set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
+        break;
+    case PCI_BASE_CLASS_NETWORK:
+        set_bit(DEVICE_CATEGORY_NETWORK, dc->categories);
+        break;
+    case PCI_BASE_CLASS_INPUT:
+        set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
+        break;
+    case PCI_BASE_CLASS_DISPLAY:
+        set_bit(DEVICE_CATEGORY_DISPLAY, dc->categories);
+        break;
+    case PCI_BASE_CLASS_PROCESSOR:
+        set_bit(DEVICE_CATEGORY_CPU, dc->categories);
+        break;
+    default:
+        set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+        break;
+    }
+
+    for (i = 0; i < PCI_NUM_REGIONS; i++) {
+        config_op_send(pdev, PCI_BASE_ADDRESS_0 + (4 * i), &orig_val, 4,
+                       MPQEMU_CMD_PCI_CFGREAD);
+        new_val = 0xffffffff;
+        config_op_send(pdev, PCI_BASE_ADDRESS_0 + (4 * i), &new_val, 4,
+                       MPQEMU_CMD_PCI_CFGWRITE);
+        config_op_send(pdev, PCI_BASE_ADDRESS_0 + (4 * i), &new_val, 4,
+                       MPQEMU_CMD_PCI_CFGREAD);
+        size = (~(new_val & 0xFFFFFFF0)) + 1;
+        config_op_send(pdev, PCI_BASE_ADDRESS_0 + (4 * i), &orig_val, 4,
+                       MPQEMU_CMD_PCI_CFGWRITE);
+        type = (new_val & 0x1) ?
+                   PCI_BASE_ADDRESS_SPACE_IO : PCI_BASE_ADDRESS_SPACE_MEMORY;
+
+        if (size) {
+            g_autofree char *name;
+            pdev->region[i].dev = pdev;
+            pdev->region[i].present = true;
+            if (type == PCI_BASE_ADDRESS_SPACE_MEMORY) {
+                pdev->region[i].memory = true;
+            }
+            name = g_strdup_printf("bar-region-%d", i);
+            memory_region_init_io(&pdev->region[i].mr, OBJECT(pdev),
+                                  &proxy_mr_ops, &pdev->region[i],
+                                  name, size);
+            pci_register_bar(dev, i, type, &pdev->region[i].mr);
+        }
+    }
+}
-- 
2.29.2

From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

Perform device reset in the remote process when QEMU performs
device reset. This is required to reset the internal state
(like registers, etc...) of emulated devices

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 7cb220a51f565dc0817bd76e2f540e89c2d2b850.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/hw/remote/mpqemu-link.h |  1 +
 hw/remote/message.c             | 22 ++++++++++++++++++++++
 hw/remote/proxy.c               | 19 +++++++++++++++++++
 3 files changed, 42 insertions(+)

From: "Denis V. Lunev" <den@openvz.org>

Original specification says that l1 table size if 64 * l1_size, which
is obviously wrong. The size of the l1 entry is 64 _bits_, not bytes.
Thus 64 is to be replaces with 8 as specification says about bytes.

There is also minor tweak, field name is renamed from l1 to l1_table,
which matches with the later text.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20210128171313.2210947-1-den@openvz.org
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

[Replace the original commit message "docs: fix mistake in dirty bitmap
feature description" as suggested by Eric Blake.
--Stefan]

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 docs/interop/parallels.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/interop/parallels.txt b/docs/interop/parallels.txt
index XXXXXXX..XXXXXXX 100644
--- a/docs/interop/parallels.txt
+++ b/docs/interop/parallels.txt
@@ -XXX,XX +XXX,XX @@ of its data area are:
   28 - 31:    l1_size
               The number of entries in the L1 table of the bitmap.
 
-  variable:   l1 (64 * l1_size bytes)
+  variable:   l1_table (8 * l1_size bytes)
               L1 offset table (in bytes)
 
 A dirty bitmap is stored using a one-level structure for the mapping to host
-- 
2.29.2