iavf sets LIBIE_MAX_MTU as netdev->max_mtu, ignoring vf_res->max_mtu from PF [1]. This allows setting an MTU beyond the actual hardware limit, causing TX queue timeouts [2]. Set correct netdev->max_mtu using vf_res->max_mtu from the PF. Note that currently PF drivers such as ice/i40e set the frame size in vf_res->max_mtu, not MTU. Convert vf_res->max_mtu to MTU before setting netdev->max_mtu. [1] # ip -j -d link show $DEV | jq '.[0].max_mtu' 16356 [2] iavf 0000:00:05.0 enp0s5: NETDEV WATCHDOG: CPU: 1: transmit queue 0 timed out 5692 ms iavf 0000:00:05.0 enp0s5: NIC Link is Up Speed is 10 Gbps Full Duplex iavf 0000:00:05.0 enp0s5: NETDEV WATCHDOG: CPU: 6: transmit queue 3 timed out 5312 ms iavf 0000:00:05.0 enp0s5: NIC Link is Up Speed is 10 Gbps Full Duplex ... Fixes: 5fa4caff59f2 ("iavf: switch to Page Pool") Signed-off-by: Kohei Enju --- Ideally we may fix ice/i40e to set max MTU (not frame size) in vf_res->max_mtu on the PF side, but this would break PF/VF API compatibility between different kernel versions and would need modifications on code that treats vf_res->max_mtu as the frame size. If it's acceptable to change the PF/VF API, this patch would be simply: netdev->max_mtu = min_not_zero(adapter->vf_res->max_mtu, LIBIE_MAX_MTU); --- drivers/net/ethernet/intel/iavf/iavf_main.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c index b625ce00b836..d911c634596a 100644 --- a/drivers/net/ethernet/intel/iavf/iavf_main.c +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c @@ -2772,7 +2772,22 @@ static void iavf_init_config_adapter(struct iavf_adapter *adapter) netdev->watchdog_timeo = 5 * HZ; netdev->min_mtu = ETH_MIN_MTU; - netdev->max_mtu = LIBIE_MAX_MTU; + + /* PF/VF API: vf_res->max_mtu is max frame size (not MTU). + * Convert to MTU. + */ + if (!adapter->vf_res->max_mtu) { + netdev->max_mtu = LIBIE_MAX_MTU; + } else if (adapter->vf_res->max_mtu < LIBETH_RX_LL_LEN + ETH_MIN_MTU || + adapter->vf_res->max_mtu > + LIBETH_RX_LL_LEN + LIBIE_MAX_MTU) { + netdev_warn_once(adapter->netdev, + "invalid max frame size %d from PF, using default MTU %d", + adapter->vf_res->max_mtu, LIBIE_MAX_MTU); + netdev->max_mtu = LIBIE_MAX_MTU; + } else { + netdev->max_mtu = adapter->vf_res->max_mtu - LIBETH_RX_LL_LEN; + } if (!is_valid_ether_addr(adapter->hw.mac.addr)) { dev_info(&pdev->dev, "Invalid MAC address %pM, using random\n", -- 2.51.0