[libvirt PATCH 2/5] qemu: add virtio-blk-vhost-vdpa capability

[Peter Krempa]

On Thu, Jun 08, 2023 at 11:00:03 +0200, Peter Krempa wrote:
> On Tue, Jun 06, 2023 at 16:11:01 -0500, Jonathon Jongsma wrote:
> > Check whether the qemu binary supports the vdpa block driver. We can't
> > rely simply on the existence of the virtio-blk-vhost-vdpa block driver
> > since the first releases of qemu didn't support fd-passing for this
> > driver. So we have to check for the 'fdset' feature on the driver
> > object. This feature will be present in the qemu 8.1.0 release and was
> > merged to qemu in commit 98b126f5.
> > 
> > Signed-off-by: Jonathon Jongsma <jjongsma at redhat.com>
> > ---
> >  src/qemu/qemu_capabilities.c | 2 ++
> >  src/qemu/qemu_capabilities.h | 1 +
> >  2 files changed, 3 insertions(+)
> > 
> > diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> > index cf85d42198..11d5ecd622 100644
> > --- a/src/qemu/qemu_capabilities.c
> > +++ b/src/qemu/qemu_capabilities.c
> > @@ -693,6 +693,7 @@ VIR_ENUM_IMPL(virQEMUCaps,
> >                "virtio-gpu.blob", /* QEMU_CAPS_VIRTIO_GPU_BLOB */
> >                "rbd-encryption-layering", /* QEMU_CAPS_RBD_ENCRYPTION_LAYERING */
> >                "rbd-encryption-luks-any", /* QEMU_CAPS_RBD_ENCRYPTION_LUKS_ANY */
> > +              "virtio-blk-vhost-vdpa", /* QEMU_CAPS_DEVICE_VIRTIO_BLK_VHOST_VDPA */
> >      );
> >  
> >  
> > @@ -1560,6 +1561,7 @@ static struct virQEMUCapsStringFlags virQEMUCapsQMPSchemaQueries[] = {
> >      { "object-add/arg-type/+iothread/thread-pool-max", QEMU_CAPS_IOTHREAD_THREAD_POOL_MAX },
> >      { "query-migrate/ret-type/blocked-reasons", QEMU_CAPS_MIGRATION_BLOCKED_REASONS },
> >      { "screendump/arg-type/format/^png", QEMU_CAPS_SCREENSHOT_FORMAT_PNG },
> > +    { "blockdev-add/arg-type/+virtio-blk-vhost-vdpa/$fdset", QEMU_CAPS_DEVICE_VIRTIO_BLK_VHOST_VDPA},
> 
> Please order this together with other 'blockdev-add' queries at the top
> and add a space before }.
> 
> Also, since I've updated capabilities now, this feature should be
> detected with the 8.1 dump, so please regenerate the output as the flag
> will be present now.

Ah, actually the caps were generated with older libblkio which doesn't
have the FD passing feature yet. I'll update and re-generate them.