net/virtio: fix descriptor addressed in Tx

Previous fix removes usage of rte_pktmbuf_prepend() to get pointer
to virtio net header which changes mbuf data_off and data_len.
Size of virtio net header is added to segment length when Tx descriptor
is composed, but segment address (calculated using data_off) is not
adjusted to take size of virtio net header into account.

Fixes: 1ae55ad38e5e ("net/virtio: fix mbuf data and packet length mismatch")
Cc: stable@dpdk.org
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 701c1cf..b5fc4ec 100644 (file)
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -657,7 +657,8 @@ virtqueue_enqueue_xmit_inorder(struct virtnet_tx *txvq,
                else
                        virtqueue_xmit_offload(hdr, cookies[i], true);
 
-               start_dp[idx].addr  = VIRTIO_MBUF_DATA_DMA_ADDR(cookies[i], vq);
+               start_dp[idx].addr  =
+                       VIRTIO_MBUF_DATA_DMA_ADDR(cookies[i], vq) - head_size;
                start_dp[idx].len   = cookies[i]->data_len + head_size;
                start_dp[idx].flags = 0;
 
@@ -704,7 +705,7 @@ virtqueue_enqueue_xmit_packed_fast(struct virtnet_tx *txvq,
        else
                virtqueue_xmit_offload(hdr, cookie, true);
 
-       dp->addr = VIRTIO_MBUF_DATA_DMA_ADDR(cookie, vq);
+       dp->addr = VIRTIO_MBUF_DATA_DMA_ADDR(cookie, vq) - head_size;
        dp->len  = cookie->data_len + head_size;
        dp->id   = id;
 
@@ -786,6 +787,7 @@ virtqueue_enqueue_xmit_packed(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
                start_dp[idx].addr = VIRTIO_MBUF_DATA_DMA_ADDR(cookie, vq);
                start_dp[idx].len  = cookie->data_len;
                if (prepend_header) {
+                       start_dp[idx].addr -= head_size;
                        start_dp[idx].len += head_size;
                        prepend_header = false;
                }
@@ -889,6 +891,7 @@ virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
                start_dp[idx].addr  = VIRTIO_MBUF_DATA_DMA_ADDR(cookie, vq);
                start_dp[idx].len   = cookie->data_len;
                if (prepend_header) {
+                       start_dp[idx].addr -= head_size;
                        start_dp[idx].len += head_size;
                        prepend_header = false;
                }