Re: [PATCH 2/4] vhost: convert byte order on SVQ used event write

[Philippe Mathieu-Daudé]

On 28/10/22 18:02, Eugenio Pérez wrote:

This causes errors on virtio modern devices on big endian hosts

Fixes: 01f8beacea2a ("vhost: toggle device callbacks using used event idx")
Signed-off-by: Eugenio Pérez <epere...@redhat.com>
---
  hw/virtio/vhost-shadow-virtqueue.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c 
b/hw/virtio/vhost-shadow-virtqueue.c
index 70766ea740..467099f5d9 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -382,7 +382,7 @@ static bool 
vhost_svq_enable_notification(VhostShadowVirtqueue *svq)
  {
      if (virtio_vdev_has_feature(svq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
          uint16_t *used_event = &svq->vring.avail->ring[svq->vring.num];
-        *used_event = svq->shadow_used_idx;
+        *used_event = cpu_to_le16(svq->shadow_used_idx);

This looks correct, but what about:

           virtio_stw_p(svq->vdev, used_event, svq->shadow_used_idx);

      } else {
          svq->vring.avail->flags &= ~cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT);
      }