diff options
| -rw-r--r-- | hw/virtio/virtio.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index efce4b343a..916457966c 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -318,6 +318,10 @@ int virtio_queue_ready(VirtQueue *vq) * Called within rcu_read_lock(). */ static int virtio_queue_empty_rcu(VirtQueue *vq) { + if (unlikely(!vq->vring.avail)) { + return 1; + } + if (vq->shadow_avail_idx != vq->last_avail_idx) { return 0; } @@ -329,6 +333,10 @@ int virtio_queue_empty(VirtQueue *vq) { bool empty; + if (unlikely(!vq->vring.avail)) { + return 1; + } + if (vq->shadow_avail_idx != vq->last_avail_idx) { return 0; } @@ -431,6 +439,10 @@ void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, return; } + if (unlikely(!vq->vring.used)) { + return; + } + idx = (idx + vq->used_idx) % vq->vring.num; uelem.id = elem->index; @@ -448,6 +460,10 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count) return; } + if (unlikely(!vq->vring.used)) { + return; + } + /* Make sure buffer is written before we update index. */ smp_wmb(); trace_virtqueue_flush(vq, count); @@ -546,6 +562,16 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, int64_t len = 0; int rc; + if (unlikely(!vq->vring.desc)) { + if (in_bytes) { + *in_bytes = 0; + } + if (out_bytes) { + *out_bytes = 0; + } + return; + } + rcu_read_lock(); idx = vq->last_avail_idx; total_bufs = in_total = out_total = 0; |