[dpdk-dev] [PATCH v5 4/5] net/i40e: fix max mtu size packets with vlan tag cannot be received by default

[SteveX Yang]

when application presets the max rx packet length and expected mtu at
the same time, driver need identify if the preset max frame size can
hold mtu data and Ether overhead completely.

if not, adjust the max frame size via mtu_set ops within dev_configure.

Fixes: ff8282f4bbcd ("net/i40e: consider QinQ when setting MTU")

Signed-off-by: SteveX Yang <stevex.yang at intel.com>
---
 drivers/net/i40e/i40e_ethdev.c    | 11 +++++++++++
 drivers/net/i40e/i40e_ethdev_vf.c | 13 ++++++++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
index 943cfe71d..272cfc7ca 100644
--- a/drivers/net/i40e/i40e_ethdev.c
+++ b/drivers/net/i40e/i40e_ethdev.c
@@ -1911,6 +1911,7 @@ i40e_dev_configure(struct rte_eth_dev *dev)
 	struct i40e_pf *pf = I40E_DEV_PRIVATE_TO_PF(dev->data->dev_private);
 	struct i40e_hw *hw = I40E_DEV_PRIVATE_TO_HW(dev->data->dev_private);
 	enum rte_eth_rx_mq_mode mq_mode = dev->data->dev_conf.rxmode.mq_mode;
+	uint32_t frame_size = dev->data->mtu + I40E_ETH_OVERHEAD;
 	int i, ret;
 
 	ret = i40e_dev_sync_phy_type(hw);
@@ -1925,6 +1926,16 @@ i40e_dev_configure(struct rte_eth_dev *dev)
 	ad->tx_simple_allowed = true;
 	ad->tx_vec_allowed = true;
 
+	/**
+	 * Reset the max frame size via mtu_set ops if preset max frame
+	 * cannot hold MTU data and Ether overhead.
+	 */
+	if (frame_size > dev->data->dev_conf.rxmode.max_rx_pkt_len) {
+		ret = i40e_dev_mtu_set(dev, dev->data->mtu);
+		if (ret != 0)
+			return ret;
+	}
+
 	if (dev->data->dev_conf.rxmode.mq_mode & ETH_MQ_RX_RSS_FLAG)
 		dev->data->dev_conf.rxmode.offloads |= DEV_RX_OFFLOAD_RSS_HASH;
 
diff --git a/drivers/net/i40e/i40e_ethdev_vf.c b/drivers/net/i40e/i40e_ethdev_vf.c
index 4d6510d1f..686f3c627 100644
--- a/drivers/net/i40e/i40e_ethdev_vf.c
+++ b/drivers/net/i40e/i40e_ethdev_vf.c
@@ -1664,6 +1664,8 @@ i40evf_dev_configure(struct rte_eth_dev *dev)
 		I40E_DEV_PRIVATE_TO_ADAPTER(dev->data->dev_private);
 	uint16_t num_queue_pairs = RTE_MAX(dev->data->nb_rx_queues,
 				dev->data->nb_tx_queues);
+	uint32_t frame_size = dev->data->mtu + I40E_ETH_OVERHEAD;
+	int ret;
 
 	/* Initialize to TRUE. If any of Rx queues doesn't meet the bulk
 	 * allocation or vector Rx preconditions we will reset it.
@@ -1676,9 +1678,18 @@ i40evf_dev_configure(struct rte_eth_dev *dev)
 	dev->data->dev_conf.intr_conf.lsc =
 		!!(dev->data->dev_flags & RTE_ETH_DEV_INTR_LSC);
 
+	/**
+	 * Reset the max frame size via mtu_set ops if preset max frame
+	 * cannot hold MTU data and Ether overhead.
+	 */
+	if (frame_size > dev->data->dev_conf.rxmode.max_rx_pkt_len) {
+		ret = i40evf_dev_mtu_set(dev, dev->data->mtu);
+		if (ret != 0)
+			return ret;
+	}
+
 	if (num_queue_pairs > vf->vsi_res->num_queue_pairs) {
 		struct i40e_hw *hw;
-		int ret;
 
 		if (rte_eal_process_type() != RTE_PROC_PRIMARY) {
 			PMD_DRV_LOG(ERR,
-- 
2.17.1