Re: [PATCH v2] virtio_balloon: prime stats vq after virtio_device_ready()

[Michael S. Tsirkin]

On Mon, Jul 06, 2026 at 10:38:18AM +0200, David Hildenbrand (Arm) wrote:
> >>> -		virtqueue_kick(vb->stats_vq);
> >>> +		disable_work(&vb->update_balloon_stats_work);
> >>
> >> That's to stop the stats queue triggering stats_request() I assume?
> > 
> > Yes.
> > 
> >> Is that
> >> valid before we actually added+kicked ourselves?
> > 
> > Why not?
> 
> I was wondering whether the spec would state something about that.

Sorry I do not get the question. Virtio API expects
callers to serialize calls for each VQ. So this just prevents the work
from running and accessing the VQ while probe calls add_buf/kick.
I'll add a comment explaining that.
But it has nothing to do with the spec.

> > 
> >> Also, can't we simply handle that in stats_request(), just ignoring it there?
> > 
> > Then we'd need to maintain a special flag and I dislike that.
> 
> I was hoping that we could use the device-ready indication, but there would be a
> small race window indeed.
> 
> -- 
> Cheers,
> 
> David