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

[Philippe Mathieu-Daudé]

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 <k...@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));
      }