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-rw-r--r--hw/virtio/virtio.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 1af2de2714..e37641a9c9 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -92,7 +92,7 @@ struct VirtQueue
uint16_t queue_index;
- int inuse;
+ unsigned int inuse;
uint16_t vector;
VirtIOHandleOutput handle_output;
@@ -1855,9 +1855,11 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
/*
* Some devices migrate VirtQueueElements that have been popped
* from the avail ring but not yet returned to the used ring.
+ * Since max ring size < UINT16_MAX it's safe to use modulo
+ * UINT16_MAX + 1 subtraction.
*/
- vdev->vq[i].inuse = vdev->vq[i].last_avail_idx -
- vdev->vq[i].used_idx;
+ vdev->vq[i].inuse = (uint16_t)(vdev->vq[i].last_avail_idx -
+ vdev->vq[i].used_idx);
if (vdev->vq[i].inuse > vdev->vq[i].vring.num) {
error_report("VQ %d size 0x%x < last_avail_idx 0x%x - "
"used_idx 0x%x",