[PATCH] vhost: fix sync dequeue offload

[xuan.ding@intel.com]

From: Xuan Ding <xuan.ding@intel.com>

This patch fixes the missing virtio net header copy in sync
dequeue path caused by refactoring, which affects dequeue
offloading.

Fixes: 6d823bb302c7("vhost: prepare sync for descriptor to mbuf refactoring")

Signed-off-by: Xuan Ding <xuan.ding@intel.com>
---
 lib/vhost/virtio_net.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index 68a26eb17d..d5a9f7c691 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -2635,9 +2635,17 @@ desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
 					   buf_iova + buf_offset, cpy_len, false) < 0)
 				goto error;
 		} else {
-			sync_fill_seg(dev, vq, cur, mbuf_offset,
-				      buf_addr + buf_offset,
-				      buf_iova + buf_offset, cpy_len, false);
+			if (hdr && cur == m) {
+				rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *, mbuf_offset),
+					(void *)((uintptr_t)(buf_addr + buf_offset)),
+					cpy_len);
+				vhost_log_cache_write_iova(dev, vq, buf_iova + buf_offset, cpy_len);
+				PRINT_PACKET(dev, (uintptr_t)(buf_addr + buf_offset), cpy_len, 0);
+			} else {
+				sync_fill_seg(dev, vq, cur, mbuf_offset,
+					buf_addr + buf_offset,
+					buf_iova + buf_offset, cpy_len, false);
+			}
 		}
 
 		mbuf_avail  -= cpy_len;
-- 
2.17.1