Re: [PATCH v3 2/2] vhost: Fix last vq queue index of devices with no cvq

[Juan Quintela]

Eugenio Pérez <eperezma@redhat.com> wrote:
> The -1 assumes that last index counts all vhost device models as having
> two queues, but they count only the ones that models the data queues.
>
> Because of that, the right change in last_index is to actually add the
> cvq, not to remove the missing one.
>
> This is not a problem to vhost-net, but it is to vhost-vdpa, which
> device model trust to reach the last index to finish starting the
> device.
>
> Tested with vp_vdpa with host's vhost=on and vhost=off, with ctrl_vq=on
> and ctrl_vq=off.
>
> Fixes: 049eb15b5fc9 ("vhost: record the last virtqueue index for the
> virtio device")
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>