[dpdk-dev] [PATCH v4 5/5] net/iavf: fix max mtu size packets with vlan tag cannot be received by default

[SteveX Yang]

testpmd will initialize default max packet length to 1518 which doesn't
include vlan tag size in ether overheader. Once, send the max mtu length
packet with vlan tag, the max packet length will exceed 1518 that will
cause packets dropped directly from NIC hw side.

iavf can support dual vlan tags that need more 8 bytes for max packet size,
so, configures the correct max packet size in dev_config ops.

Fixes: 02d212ca3125 ("net/iavf: rename remaining avf strings")

Signed-off-by: SteveX Yang <stevex.yang at intel.com>
---
 drivers/net/iavf/iavf_ethdev.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/iavf/iavf_ethdev.c b/drivers/net/iavf/iavf_ethdev.c
index a88d53ab0..635d781eb 100644
--- a/drivers/net/iavf/iavf_ethdev.c
+++ b/drivers/net/iavf/iavf_ethdev.c
@@ -258,6 +258,8 @@ iavf_dev_configure(struct rte_eth_dev *dev)
 		IAVF_DEV_PRIVATE_TO_ADAPTER(dev->data->dev_private);
 	struct iavf_info *vf =  IAVF_DEV_PRIVATE_TO_VF(ad);
 	struct rte_eth_conf *dev_conf = &dev->data->dev_conf;
+	uint32_t frame_size = dev->data->mtu + IAVF_ETH_OVERHEAD;
+	int ret;
 
 	ad->rx_bulk_alloc_allowed = true;
 	/* Initialize to TRUE. If any of Rx queues doesn't meet the
@@ -269,6 +271,16 @@ iavf_dev_configure(struct rte_eth_dev *dev)
 	if (dev->data->dev_conf.rxmode.mq_mode & ETH_MQ_RX_RSS_FLAG)
 		dev->data->dev_conf.rxmode.offloads |= DEV_RX_OFFLOAD_RSS_HASH;
 
+	/**
+	 * Considering QinQ packet, max frame size should be equal or
+	 * larger than total size of MTU and Ether overhead.
+	 */
+	if (frame_size > dev->data->dev_conf.rxmode.max_rx_pkt_len) {
+		ret = iavf_dev_mtu_set(dev, dev->data->mtu);
+		if (ret != 0)
+			return ret;
+	}
+
 	/* Vlan stripping setting */
 	if (vf->vf_res->vf_cap_flags & VIRTCHNL_VF_OFFLOAD_VLAN) {
 		if (dev_conf->rxmode.offloads & DEV_RX_OFFLOAD_VLAN_STRIP)
-- 
2.17.1