libblkio 1.1.0 [1] introduces a virtio-blk-vfio-pci driver, which
accesses a virtio-blk PCI device using VFIO. Add a corresponding
BlockDriver.

[1] https://gitlab.com/libblkio/libblkio/-/tree/v1.1.0

Signed-off-by: Alberto Faria <afaria@redhat.com>
---

This is dependent on a pending libblkio fix [2], so we may want to wait
for a new libblkio release before queueing this.

[2] https://gitlab.com/libblkio/libblkio/-/merge_requests/140

 block/blkio.c        |  8 ++++++++
 qapi/block-core.json | 18 ++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/block/blkio.c b/block/blkio.c
index 82f26eedd2..f55eb774b4 100644
--- a/block/blkio.c
+++ b/block/blkio.c
@@ -25,6 +25,7 @@
  */
 #define DRIVER_IO_URING "io_uring"
 #define DRIVER_NVME_IO_URING "nvme-io_uring"
+#define DRIVER_VIRTIO_BLK_VFIO_PCI "virtio-blk-vfio-pci"
 #define DRIVER_VIRTIO_BLK_VHOST_USER "virtio-blk-vhost-user"
 #define DRIVER_VIRTIO_BLK_VHOST_VDPA "virtio-blk-vhost-vdpa"
 
@@ -704,6 +705,8 @@ static int blkio_file_open(BlockDriverState *bs, QDict *options, int flags,
         ret = blkio_io_uring_open(bs, options, flags, errp);
     } else if (strcmp(blkio_driver, DRIVER_NVME_IO_URING) == 0) {
         ret = blkio_nvme_io_uring(bs, options, flags, errp);
+    } else if (strcmp(blkio_driver, DRIVER_VIRTIO_BLK_VFIO_PCI) == 0) {
+        ret = blkio_virtio_blk_common_open(bs, options, flags, errp);
     } else if (strcmp(blkio_driver, DRIVER_VIRTIO_BLK_VHOST_USER) == 0) {
         ret = blkio_virtio_blk_common_open(bs, options, flags, errp);
     } else if (strcmp(blkio_driver, DRIVER_VIRTIO_BLK_VHOST_VDPA) == 0) {
@@ -989,6 +992,10 @@ static BlockDriver bdrv_nvme_io_uring = BLKIO_DRIVER(
     .bdrv_needs_filename = true,
 );
 
+static BlockDriver bdrv_virtio_blk_vfio_pci = BLKIO_DRIVER(
+    DRIVER_VIRTIO_BLK_VFIO_PCI
+);
+
 static BlockDriver bdrv_virtio_blk_vhost_user = BLKIO_DRIVER(
     DRIVER_VIRTIO_BLK_VHOST_USER
 );
@@ -1001,6 +1008,7 @@ static void bdrv_blkio_init(void)
 {
     bdrv_register(&bdrv_io_uring);
     bdrv_register(&bdrv_nvme_io_uring);
+    bdrv_register(&bdrv_virtio_blk_vfio_pci);
     bdrv_register(&bdrv_virtio_blk_vhost_user);
     bdrv_register(&bdrv_virtio_blk_vhost_vdpa);
 }
diff --git a/qapi/block-core.json b/qapi/block-core.json
index cb5079e645..81bbb0b893 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2960,6 +2960,7 @@
             'raw', 'rbd',
             { 'name': 'replication', 'if': 'CONFIG_REPLICATION' },
             'ssh', 'throttle', 'vdi', 'vhdx',
+            { 'name': 'virtio-blk-vfio-pci', 'if': 'CONFIG_BLKIO' },
             { 'name': 'virtio-blk-vhost-user', 'if': 'CONFIG_BLKIO' },
             { 'name': 'virtio-blk-vhost-vdpa', 'if': 'CONFIG_BLKIO' },
             'vmdk', 'vpc', 'vvfat' ] }
@@ -3711,6 +3712,20 @@
   'data': { 'filename': 'str' },
   'if': 'CONFIG_BLKIO' }
 
+##
+# @BlockdevOptionsVirtioBlkVfioPci:
+#
+# Driver specific block device options for the virtio-blk-vfio-pci backend.
+#
+# @path: path to the PCI device's sysfs directory (e.g.
+#        /sys/bus/pci/devices/0000:00:01.0).
+#
+# Since: 7.2
+##
+{ 'struct': 'BlockdevOptionsVirtioBlkVfioPci',
+  'data': { 'path': 'str' },
+  'if': 'CONFIG_BLKIO' }
+
 ##
 # @BlockdevOptionsVirtioBlkVhostUser:
 #
@@ -4390,6 +4405,9 @@
       'throttle':   'BlockdevOptionsThrottle',
       'vdi':        'BlockdevOptionsGenericFormat',
       'vhdx':       'BlockdevOptionsGenericFormat',
+      'virtio-blk-vfio-pci':
+                    { 'type': 'BlockdevOptionsVirtioBlkVfioPci',
+                      'if': 'CONFIG_BLKIO' },
       'virtio-blk-vhost-user':
                     { 'type': 'BlockdevOptionsVirtioBlkVhostUser',
                       'if': 'CONFIG_BLKIO' },
-- 
2.37.3

On Fri, Oct 28, 2022 at 02:16:35PM +0100, Alberto Faria wrote:
> libblkio 1.1.0 [1] introduces a virtio-blk-vfio-pci driver, which
> accesses a virtio-blk PCI device using VFIO. Add a corresponding
> BlockDriver.
> 
> [1] https://gitlab.com/libblkio/libblkio/-/tree/v1.1.0
> 
> Signed-off-by: Alberto Faria <afaria@redhat.com>
> ---
> 
> This is dependent on a pending libblkio fix [2], so we may want to wait
> for a new libblkio release before queueing this.
> 
> [2] https://gitlab.com/libblkio/libblkio/-/merge_requests/140
> 
>  block/blkio.c        |  8 ++++++++
>  qapi/block-core.json | 18 ++++++++++++++++++
>  2 files changed, 26 insertions(+)

Thanks, applied to my block tree:
https://gitlab.com/stefanha/qemu/commits/block

Stefan

On Fri, Oct 28, 2022 at 2:17 PM Alberto Faria <afaria@redhat.com> wrote:
> libblkio 1.1.0 [1] introduces a virtio-blk-vfio-pci driver, which
> accesses a virtio-blk PCI device using VFIO. Add a corresponding
> BlockDriver.
>
> [1] https://gitlab.com/libblkio/libblkio/-/tree/v1.1.0
>
> Signed-off-by: Alberto Faria <afaria@redhat.com>

I forgot to mention this is based on Stefan's block tree:
https://gitlab.com/stefanha/qemu/-/commits/block