Re: [PATCH 4/4] vhost: convert byte order on avail_event read

[Philippe Mathieu-Daudé]

On 28/10/22 18:02, Eugenio Pérez wrote:
> This causes errors on virtio modern devices on big endian hosts
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
>   hw/virtio/vhost-shadow-virtqueue.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/hw/virtio/vhost-shadow-virtqueue.c 
> b/hw/virtio/vhost-shadow-virtqueue.c
> index 18a49e1ecb..3131903edd 100644
> --- a/hw/virtio/vhost-shadow-virtqueue.c
> +++ b/hw/virtio/vhost-shadow-virtqueue.c
> @@ -231,7 +231,8 @@ static void vhost_svq_kick(VhostShadowVirtqueue *svq)
>           size_t num = svq->vring.num;
>           uint16_t *avail_event = (uint16_t *)&svq->vring.used->ring[num];
>   

  uint16_t avail_event = virtio_lduw_p(svq->vdev,
                                       &svq->vring.used->ring[num]);
  needs_kick = vring_need_event(avail_event,
                                svq->shadow_avail_idx,
                                svq->shadow_avail_idx - 1);

> -        needs_kick = vring_need_event(*avail_event, svq->shadow_avail_idx,
> +        needs_kick = vring_need_event(le16_to_cpu(*avail_event),
> +                                      svq->shadow_avail_idx,
>                                         svq->shadow_avail_idx - 1);
>       } else {
>           needs_kick = !(svq->vring.used->flags & VRING_USED_F_NO_NOTIFY);