Re: [PATCH v2] vdpa: Fix endian bugs in shadow virtqueue

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 12/2/25 17:49, Konstantin Shkolnyy wrote:
> VDPA didn't work on a big-endian machine due to missing/incorrect
> CPU<->LE data format conversions.
> 
> Signed-off-by: Konstantin Shkolnyy <kshk@linux.ibm.com>
> ---
> Changes in v2: Change desc_next[] from LE format to "CPU".
> 
>   hw/virtio/vhost-shadow-virtqueue.c | 18 ++++++++++--------
>   1 file changed, 10 insertions(+), 8 deletions(-)


> @@ -228,10 +228,12 @@ static void vhost_svq_kick(VhostShadowVirtqueue *svq)
>       smp_mb();
>   
>       if (virtio_vdev_has_feature(svq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
> -        uint16_t avail_event = *(uint16_t *)(&svq->vring.used->ring[svq->vring.num]);
> +        uint16_t avail_event = le16_to_cpu(
> +                *(uint16_t *)(&svq->vring.used->ring[svq->vring.num]));

Nitpicking, sometimes using the ld/st API is cleaner (here lduw_le_p).

>           needs_kick = vring_need_event(avail_event, svq->shadow_avail_idx, svq->shadow_avail_idx - 1);
>       } else {
> -        needs_kick = !(svq->vring.used->flags & VRING_USED_F_NO_NOTIFY);
> +        needs_kick =
> +                !(svq->vring.used->flags & cpu_to_le16(VRING_USED_F_NO_NOTIFY));
>       }