diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 5828ed14df..22bd1ac34e 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -796,13 +796,13 @@ static void virtqueue_undo_map_desc(unsigned int out_num, unsigned int in_num,
 }
 
 static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg,
-                                hwaddr *addr, unsigned int *num_sg,
+                                hwaddr *addr, unsigned int num_sg,
                                 int is_write)
 {
     unsigned int i;
     hwaddr len;
 
-    for (i = 0; i < *num_sg; i++) {
+    for (i = 0; i < num_sg; i++) {
         len = sg[i].iov_len;
         sg[i].iov_base = dma_memory_map(vdev->dma_as,
                                         addr[i], &len, is_write ?
@@ -821,8 +821,8 @@ static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg,
 
 void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem)
 {
-    virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, &elem->in_num, 1);
-    virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, &elem->out_num, 0);
+    virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, elem->in_num, 1);
+    virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, elem->out_num, 0);
 }
 
 static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num)