[dpdk-dev] [PATCH v1 5/5] net/i40e: fix max mtu size packets with vlan tag cannot be received by default

[Ananyev, Konstantin]

> testpmd will initialize default max packet length to 1518 which does'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. But for i40e/i40evf,
> they should support dual vlan tags that need more 8 bytes for max packet
> size, so, configure the correct max packet size in dev_config ops.
> 
> 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    | 10 ++++++++++
>  drivers/net/i40e/i40e_ethdev_vf.c | 11 +++++++++++
>  2 files changed, 21 insertions(+)
> 
> diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
> index 841447228..787ff61c0 100644
> --- a/drivers/net/i40e/i40e_ethdev.c
> +++ b/drivers/net/i40e/i40e_ethdev.c
> @@ -1917,6 +1917,7 @@ i40e_dev_configure(struct rte_eth_dev *dev)
>  	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;
>  	int i, ret;
> +	struct rte_eth_rxmode *rxmode = &dev->data->dev_conf.rxmode;
> 
>  	ret = i40e_dev_sync_phy_type(hw);
>  	if (ret)
> @@ -1930,6 +1931,15 @@ i40e_dev_configure(struct rte_eth_dev *dev)
>  	ad->tx_simple_allowed = true;
>  	ad->tx_vec_allowed = true;
> 
> +	/* Considering QinQ packet, max frame size should be MTU and
> +	 * corresponding ether overhead.
> +	 */
> +	if (dev->data->mtu == RTE_ETHER_MTU &&
> +		rxmode->max_rx_pkt_len == RTE_ETHER_MAX_LEN) {

Wonder why that particular max_rx_pkt_len and mtu values are important?
Shouldn't we always do here same calculations as we do in i40e_dev_mtu_set()?


> +		rxmode->max_rx_pkt_len = RTE_ETHER_MTU + I40E_ETH_OVERHEAD;
> +		rxmode->offloads |= DEV_RX_OFFLOAD_JUMBO_FRAME;
> +	}
> +
>  	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 b755350cd..7410563db 100644
> --- a/drivers/net/i40e/i40e_ethdev_vf.c
> +++ b/drivers/net/i40e/i40e_ethdev_vf.c
> @@ -1669,6 +1669,7 @@ 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);
> +	struct rte_eth_rxmode *rxmode = &dev->data->dev_conf.rxmode;
> 
>  	/* Initialize to TRUE. If any of Rx queues doesn't meet the bulk
>  	 * allocation or vector Rx preconditions we will reset it.
> @@ -1681,6 +1682,16 @@ i40evf_dev_configure(struct rte_eth_dev *dev)
>  	dev->data->dev_conf.intr_conf.lsc =
>  		!!(dev->data->dev_flags & RTE_ETH_DEV_INTR_LSC);
> 
> +
> +	/* Considering QinQ packet, max frame size should be MTU and
> +	 * corresponding ether overhead.
> +	 */
> +	if (dev->data->mtu == RTE_ETHER_MTU &&
> +		rxmode->max_rx_pkt_len == RTE_ETHER_MAX_LEN) {
> +		rxmode->max_rx_pkt_len = RTE_ETHER_MTU + I40E_ETH_OVERHEAD;
> +		rxmode->offloads |= DEV_RX_OFFLOAD_JUMBO_FRAME;
> +	}
> +
>  	if (num_queue_pairs > vf->vsi_res->num_queue_pairs) {
>  		struct i40e_hw *hw;
>  		int ret;
> --
> 2.17.1