Re: [Qemu-devel] [PATCH 5/6] vhost: move virtio 1.0 check to cross-endian helper

[Greg Kurz <gkurz@linux.vnet.ibm.com>]

On Thu, 7 Jan 2016 21:07:26 +0100
Laurent Vivier <lvivier@redhat.com> wrote:

> 
> 
> On 07/01/2016 12:32, Greg Kurz wrote:
> > Indeed vhost doesn't need to ask for vring endian fixing if the device is
> > virtio 1.0, since it is already handled by the in-kernel vhost driver. This
> > patch simply consolidates the logic into the existing helper.
> > 
> > Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> > Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> > ---
> >  hw/virtio/vhost.c |    9 +++++----
> >  1 file changed, 5 insertions(+), 4 deletions(-)
> > 
> > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> > index 2e1e792d599e..aef750df22ad 100644
> > --- a/hw/virtio/vhost.c
> > +++ b/hw/virtio/vhost.c
> > @@ -750,6 +750,9 @@ static void vhost_log_stop(MemoryListener *listener,
> >  
> >  static inline bool vhost_needs_vring_endian(VirtIODevice *vdev)
> >  {
> > +    if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
> > +        return false;
> > +    }
> >  #ifdef TARGET_IS_BIENDIAN
> >  #ifdef HOST_WORDS_BIGENDIAN
> >      return !virtio_is_big_endian(vdev);
> > @@ -811,8 +814,7 @@ static int vhost_virtqueue_start(struct vhost_dev *dev,
> >          return -errno;
> >      }
> >  
> > -    if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1) &&
> > -        vhost_needs_vring_endian(vdev)) {
> > +    if (vhost_needs_vring_endian(vdev)) {
> >          r = vhost_virtqueue_set_vring_endian_legacy(dev,
> >                                                      virtio_is_big_endian(vdev),
> >                                                      vhost_vq_index);
> > @@ -908,8 +910,7 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev,
> >      /* In the cross-endian case, we need to reset the vring endianness to
> >       * native as legacy devices expect so by default.
> >       */
> > -    if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1) &&
> > -        vhost_needs_vring_endian(vdev)) {
> > +    if (vhost_needs_vring_endian(vdev)) {
> >          r = vhost_virtqueue_set_vring_endian_legacy(dev,
> >                                                      !virtio_is_big_endian(vdev),
> >                                                      vhost_vq_index);
> > 
> > 
> 
> IMHO, I think 4/6 and 5/6 can be merged as there is no change in the
> behavior and they are only consolidating code.
> 

Maybe but I'm not sure it is really needed to help acceptance.
FWIW Cornelia already reviewed both patches.