Signed-off-by: Ilya Maximets <redacted>
---
Version 2:
	* Rebased on top of current master.
	* host's address now checked in meargeable case,
	  because needed refactoring already done.
	* Commit-message changed because old issue with
	  virtio reload accidentially fixed by commit
	  0823c1cb0a73.

 lib/librte_vhost/vhost_rxtx.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
index 15ca956..31e8b58 100644
--- a/lib/librte_vhost/vhost_rxtx.c
+++ b/lib/librte_vhost/vhost_rxtx.c

@@ -147,10 +147,10 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
 
 	desc = &vq->desc[desc_idx];
-	if (unlikely(desc->len < dev->vhost_hlen))
+	desc_addr = gpa_to_vva(dev, desc->addr);
+	if (unlikely(desc->len < dev->vhost_hlen || !desc_addr))
 		return -1;

 
-	desc_addr = gpa_to_vva(dev, desc->addr);
 	rte_prefetch0((void *)(uintptr_t)desc_addr);
 
 	virtio_enqueue_offload(m, &virtio_hdr.hdr);

@@ -182,7 +182,10 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
 				return -1;
 
 			desc = &vq->desc[desc->next];
-			desc_addr   = gpa_to_vva(dev, desc->addr);
+			desc_addr = gpa_to_vva(dev, desc->addr);
+			if (unlikely(!desc_addr))
+				return -1;
+
 			desc_offset = 0;
 			desc_avail  = desc->len;
 		}

@@ -387,10 +390,10 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	LOG_DEBUG(VHOST_DATA, "(%d) current index %d | end index %d\n",
 		dev->vid, cur_idx, end_idx);
 
-	if (buf_vec[vec_idx].buf_len < dev->vhost_hlen)
-		return -1;
-
 	desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr);
+	if (buf_vec[vec_idx].buf_len < dev->vhost_hlen || !desc_addr)
+		return 0;
+
 	rte_prefetch0((void *)(uintptr_t)desc_addr);
 
 	virtio_hdr.num_buffers = end_idx - start_idx;

@@ -425,6 +428,8 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
 
 			vec_idx++;
 			desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr);
+			if (unlikely(!desc_addr))
+				return 0;
 
 			/* Prefetch buffer address. */
 			rte_prefetch0((void *)(uintptr_t)desc_addr);

@@ -507,7 +512,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
 		*(volatile uint16_t *)&vq->used->idx += nr_used;
 		vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 			sizeof(vq->used->idx));
-		vq->last_used_idx = end;
+		vq->last_used_idx += nr_used;