Re: [Qemu-devel] [PATCH V4 3/3] virtio-blk: only clear VIRTIO_F_ANY_LAYOUT for legacy device

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Mon, 27 Jul 2015 14:22:37 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Mon, Jul 27, 2015 at 12:30:19PM +0200, Paolo Bonzini wrote:
> > 
> > 
> > On 27/07/2015 11:49, Jason Wang wrote:
> > > So this patch only clear VIRTIO_F_LAYOUT for legacy device.
> > > 
> > > Cc: Stefan Hajnoczi <stefanha@redhat.com>
> > > Cc: Kevin Wolf <kwolf@redhat.com>
> > > Cc: qemu-block@nongnu.org
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > > ---
> > >  hw/block/virtio-blk.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> > > index 9acbc3a..1d3f26c 100644
> > > --- a/hw/block/virtio-blk.c
> > > +++ b/hw/block/virtio-blk.c
> > > @@ -731,7 +731,6 @@ static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features,
> > >      virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY);
> > >      virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
> > >      virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
> > > -    virtio_clear_feature(&features, VIRTIO_F_ANY_LAYOUT);
> > >      if (__virtio_has_feature(features, VIRTIO_F_VERSION_1)) {
> > >          if (s->conf.scsi) {
> > >              error_setg(errp, "Virtio 1.0 does not support scsi passthrough!");
> > > @@ -739,6 +738,7 @@ static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features,
> > >          }
> > >          virtio_add_feature(&features, VIRTIO_F_ANY_LAYOUT);
> > >      } else {
> > > +        virtio_clear_feature(&features, VIRTIO_F_ANY_LAYOUT);
> > >          virtio_add_feature(&features, VIRTIO_BLK_F_SCSI);
> > >      }
> > 
> > This patch is unnecessary, since the feature is added back below under
> > "if (__virtio_has_feature(features, VIRTIO_F_VERSION_1))".
> > 
> > Paolo
> 
> It's needed so we can apply
>     virtio: set any_layout in virtio core

So what's the plan on all those virtio feature patches? It's hard to
keep track about what is based upon what, and what the end result looks
like. I don't have a good feeling about doing this that late in the 2.4
cycle.