Re: [Qemu-devel] [PATCH v4 4/6] vhost: move virtio 1.0 check to cross-endian helper

[Laurent Vivier <lvivier@redhat.com>]

On 05/02/2016 11:45, 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.
> 
> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>

Reviewed-by: Laurent Vivier <lvivier@redhat.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 6fea07c8ae15..bb17177f5e7e 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -751,6 +751,9 @@ 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);
> @@ -812,8 +815,7 @@ 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);
> @@ -909,8 +911,7 @@ 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);
> 
>