On Thu, Jul 20, 2023 at 2:56 PM Michal Prívozník <mprivozn@redhat.com> wrote:
On 7/20/23 08:22, Han Han wrote:
> These two attributes are supported for vhost-user-blk as well.
>
> Signed-off-by: Han Han <hhan@redhat.com>
> ---
>  docs/formatdomain.rst | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
> index 4af0b82569..447ab32c01 100644
> --- a/docs/formatdomain.rst
> +++ b/docs/formatdomain.rst
> @@ -3275,9 +3275,9 @@ paravirtualized driver is specified via the ``disk`` element.
>        "virtio" ``bus`` and "pci" or "ccw" ``address`` types. :since:`Since 1.2.8
>        (QEMU 2.1)`
>     -  The optional ``queues`` attribute specifies the number of virt queues for
> -      virtio-blk. ( :since:`Since 3.9.0` )
> +      virtio-blk or vhost-user-blk. ( :since:`Since 3.9.0` )

This doesn't feel right. The vhost-user-blk disk was introduced fairly
recently and 3.9.0 is just ancient. Digging into commits, vhost-user-blk
disk was introduced in v7.1.0 and I didn't check whether it supported
the attribute from the very beginning.

Thank you for pointing this out.  It looks libvirt allows the user to set the queues for
all the bus=='virtio': 
https://gitlab.com/libvirt/libvirt/-/blob/v7.1.0/src/conf/domain_validate.c#L465

So vhost-user-blk could use the queues at the beginning.
I think if we want to document the attribute then we should probably do
it like this:

The optional ``queues`` attribute specifies the number of virt queues
for virtio-blk ( :sinnce:`Since 3.9.0) or vhost-user-blk ( :since:`Since
X.Y.Z` ).

>     -  The optional ``queue_size`` attribute specifies the size of each virt
> -      queue for virtio-blk. ( :since:`Since 7.8.0` )
> +      queue for virtio-blk or vhost-user-blk. ( :since:`Since 7.8.0` )
>     -  For virtio disks, `Virtio-related options`_ can also
>        be set. ( :since:`Since 3.5.0` )
>     -  The optional ``metadata_cache`` subelement controls aspects related to the

I have not checked this later hunk.

Michal