[PATCH v3 5/8] virtio: retrieve hdr_size from hw->vtnet_hdr_size

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

The mergeable virtio net hdr format has been the standard and the
only virtio net hdr format since virtio 1.0. Therefore, we can
not hardcode hdr_size to "sizeof(struct virtio_net_hdr)" any more
at virtio_recv_pkts(), otherwise, there would be a mismatch of
hdr size from rte_vhost_enqueue_burst() and virtio_recv_pkts(),
leading a packet corruption.

Instead, we should retrieve it from hw->vtnet_hdr_size; we will
do proper settings at eth_virtio_dev_init() in later patches.

Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
---

v3: retrieve hdr_size from hw->vtnet_hdr_size for simple rxtx
    code path as well: it should not break anything, as simple
    rx and mergeable rx still will not co-exist.
---
 drivers/net/virtio/virtio_rxtx.c        |  6 ++++--
 drivers/net/virtio/virtio_rxtx_simple.c | 12 ++++++------
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index b7267c0..41a1366 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -560,7 +560,7 @@ virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 	struct rte_mbuf *rcv_pkts[VIRTIO_MBUF_BURST_SZ];
 	int error;
 	uint32_t i, nb_enqueued;
-	const uint32_t hdr_size = sizeof(struct virtio_net_hdr);
+	uint32_t hdr_size;
 
 	nb_used = VIRTQUEUE_NUSED(rxvq);
 
@@ -580,6 +580,7 @@ virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 	hw = rxvq->hw;
 	nb_rx = 0;
 	nb_enqueued = 0;
+	hdr_size = hw->vtnet_hdr_size;
 
 	for (i = 0; i < num ; i++) {
 		rxm = rcv_pkts[i];
@@ -664,7 +665,7 @@ virtio_recv_mergeable_pkts(void *rx_queue,
 	uint32_t seg_num;
 	uint16_t extra_idx;
 	uint32_t seg_res;
-	const uint32_t hdr_size = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	uint32_t hdr_size;
 
 	nb_used = VIRTQUEUE_NUSED(rxvq);
 
@@ -682,6 +683,7 @@ virtio_recv_mergeable_pkts(void *rx_queue,
 	seg_num = 0;
 	extra_idx = 0;
 	seg_res = 0;
+	hdr_size = hw->vtnet_hdr_size;
 
 	while (i < nb_used) {
 		struct virtio_net_hdr_mrg_rxbuf *header;
diff --git a/drivers/net/virtio/virtio_rxtx_simple.c b/drivers/net/virtio/virtio_rxtx_simple.c
index ff3c11a..3e66e8b 100644
--- a/drivers/net/virtio/virtio_rxtx_simple.c
+++ b/drivers/net/virtio/virtio_rxtx_simple.c
@@ -81,9 +81,9 @@ virtqueue_enqueue_recv_refill_simple(struct virtqueue *vq,
 
 	start_dp = vq->vq_ring.desc;
 	start_dp[desc_idx].addr = (uint64_t)((uintptr_t)cookie->buf_physaddr +
-		RTE_PKTMBUF_HEADROOM - sizeof(struct virtio_net_hdr));
+		RTE_PKTMBUF_HEADROOM - vq->hw->vtnet_hdr_size);
 	start_dp[desc_idx].len = cookie->buf_len -
-		RTE_PKTMBUF_HEADROOM + sizeof(struct virtio_net_hdr);
+		RTE_PKTMBUF_HEADROOM + vq->hw->vtnet_hdr_size;
 
 	vq->vq_free_cnt--;
 	vq->vq_avail_idx++;
@@ -120,9 +120,9 @@ virtio_rxq_rearm_vec(struct virtqueue *rxvq)
 
 		start_dp[i].addr =
 			(uint64_t)((uintptr_t)sw_ring[i]->buf_physaddr +
-			RTE_PKTMBUF_HEADROOM - sizeof(struct virtio_net_hdr));
+			RTE_PKTMBUF_HEADROOM - rxvq->hw->vtnet_hdr_size);
 		start_dp[i].len = sw_ring[i]->buf_len -
-			RTE_PKTMBUF_HEADROOM + sizeof(struct virtio_net_hdr);
+			RTE_PKTMBUF_HEADROOM + rxvq->hw->vtnet_hdr_size;
 	}
 
 	rxvq->vq_avail_idx += RTE_VIRTIO_VPMD_RX_REARM_THRESH;
@@ -175,8 +175,8 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 	len_adjust = _mm_set_epi16(
 		0, 0,
 		0,
-		(uint16_t) -sizeof(struct virtio_net_hdr),
-		0, (uint16_t) -sizeof(struct virtio_net_hdr),
+		(uint16_t) -rxvq->hw->vtnet_hdr_size,
+		0, (uint16_t) -rxvq->hw->vtnet_hdr_size,
 		0, 0);
 
 	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
-- 
1.9.0