On Wed, Feb 12, 2025 at 5:49 PM Konstantin Shkolnyy <k...@linux.ibm.com> wrote:
>
> VDPA didn't work on a big-endian machine due to missing/incorrect
> CPU<->LE data format conversions.
>
Fixes: 10857ec0ad ("vhost: Add VhostShadowVirtqueue")
> Signed-off-by: Konstantin Shkolnyy <k...@linux.ibm.com>
Acked-by: Eugenio Pérez <epere...@redhat.com>
Thanks!
> ---
> 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(-)
>
> diff --git a/hw/virtio/vhost-shadow-virtqueue.c
> b/hw/virtio/vhost-shadow-virtqueue.c
> index 37aca8b431..4af0d7c669 100644
> --- a/hw/virtio/vhost-shadow-virtqueue.c
> +++ b/hw/virtio/vhost-shadow-virtqueue.c
> @@ -165,10 +165,10 @@ static bool
> vhost_svq_vring_write_descs(VhostShadowVirtqueue *svq, hwaddr *sg,
> descs[i].len = cpu_to_le32(iovec[n].iov_len);
>
> last = i;
> - i = cpu_to_le16(svq->desc_next[i]);
> + i = svq->desc_next[i];
> }
>
> - svq->free_head = le16_to_cpu(svq->desc_next[last]);
> + svq->free_head = svq->desc_next[last];
> return true;
> }
>
> @@ -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]));
> 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));
> }
>
> if (!needs_kick) {
> @@ -365,7 +367,7 @@ static bool vhost_svq_more_used(VhostShadowVirtqueue *svq)
> return true;
> }
>
> - svq->shadow_used_idx = cpu_to_le16(*(volatile uint16_t *)used_idx);
> + svq->shadow_used_idx = le16_to_cpu(*(volatile uint16_t *)used_idx);
>
> return svq->last_used_idx != svq->shadow_used_idx;
> }
> @@ -383,7 +385,7 @@ static bool
> vhost_svq_enable_notification(VhostShadowVirtqueue *svq)
> {
> if (virtio_vdev_has_feature(svq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
> uint16_t *used_event = (uint16_t
> *)&svq->vring.avail->ring[svq->vring.num];
> - *used_event = svq->shadow_used_idx;
> + *used_event = cpu_to_le16(svq->shadow_used_idx);
> } else {
> svq->vring.avail->flags &= ~cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT);
> }
> @@ -408,7 +410,7 @@ static uint16_t vhost_svq_last_desc_of_chain(const
> VhostShadowVirtqueue *svq,
> uint16_t num, uint16_t i)
> {
> for (uint16_t j = 0; j < (num - 1); ++j) {
> - i = le16_to_cpu(svq->desc_next[i]);
> + i = svq->desc_next[i];
> }
>
> return i;
> @@ -683,7 +685,7 @@ void vhost_svq_start(VhostShadowVirtqueue *svq,
> VirtIODevice *vdev,
> svq->desc_state = g_new0(SVQDescState, svq->vring.num);
> svq->desc_next = g_new0(uint16_t, svq->vring.num);
> for (unsigned i = 0; i < svq->vring.num - 1; i++) {
> - svq->desc_next[i] = cpu_to_le16(i + 1);
> + svq->desc_next[i] = i + 1;
> }
> }
>
> --
> 2.34.1
>
