libvduse: Fix assignment in vring_set_avail_event

Since the assignment is causing a compiler warning, fix it by using
memcpy instead.

  CC       libvduse.o
libvduse.c: In function ‘vring_set_avail_event’:
libvduse.c:603:7: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasin]
  603 |     *((uint16_t *)&vq->vring.used->ring[vq->vring.num]) = htole16(val);
      |      ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Suggested-by: Xie Yongji <xieyongji@bytedance.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <4a0fe2a6436464473119fdbf0bc4076b36fbb37f.1671741278.git.marcel@holtmann.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/subprojects/libvduse/libvduse.c b/subprojects/libvduse/libvduse.c
index 338ad5e352e74c3a5d0d3634d72969d9a317e7b8..377959a0b4fbd141a11bb8957d43f61ddda8b885 100644 (file)
--- a/subprojects/libvduse/libvduse.c
+++ b/subprojects/libvduse/libvduse.c
@@ -582,7 +582,8 @@ void vduse_queue_notify(VduseVirtq *vq)
 
 static inline void vring_set_avail_event(VduseVirtq *vq, uint16_t val)
 {
-    *((uint16_t *)&vq->vring.used->ring[vq->vring.num]) = htole16(val);
+    uint16_t val_le = htole16(val);
+    memcpy(&vq->vring.used->ring[vq->vring.num], &val_le, sizeof(uint16_t));
 }
 
 static bool vduse_queue_map_single_desc(VduseVirtq *vq, unsigned int *p_num_sg,