Re: [Qemu-devel] [PULL v3 26/28] vhost: drop legacy vring layout bits

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Nov 15, 2016 at 09:35:34PM +0100, Greg Kurz wrote:
> On Tue, 15 Nov 2016 21:22:31 +0200
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > From: Greg Kurz <groug@kaod.org>
> > 
> > The legacy vring layout is not used anymore as we use the separate
> > mappings even for legacy devices.
> > This patch simply removes it.
> > 
> > This also fixes a bug with virtio 1 devices when the vring descriptor table
> > is mapped at a higher address than the used vring because the following
> > function may return an insanely great value:
> > 
> > hwaddr virtio_queue_get_ring_size(VirtIODevice *vdev, int n)
> > {
> >     return vdev->vq[n].vring.used - vdev->vq[n].vring.desc +
> >            virtio_queue_get_used_size(vdev, n);
> > }
> > 
> > and the mapping fails.
> > 
> 
> Michael,
> 
> I see the "vhost: adapt vhost_verify_ring_mappings() to virtio  1 ring layout"
> patch got Cc'ed to stable... any reason for not doing the same with this patch
> since it fixes the bug which motivated the whole series ?
> 
> Cheers.
> 
> --
> Greg

Not really, I just forgot. Pls go ahead and CC stable.

-- 
MST