From cb2f74685f76388b16f4750faaf5dafed6163dc0 Mon Sep 17 00:00:00 2001 From: Adham Faris Date: Wed, 14 Dec 2022 16:02:57 +0200 Subject: [PATCH] net/mlx5e: Fix hw mtu initializing at XDP SQ allocation [ Upstream commit 1e267ab88dc44c48f556218f7b7f14c76f7aa066 ] Current xdp xmit functions logic (mlx5e_xmit_xdp_frame_mpwqe or mlx5e_xmit_xdp_frame), validates xdp packet length by comparing it to hw mtu (configured at xdp sq allocation) before xmiting it. This check does not account for ethernet fcs length (calculated and filled by the nic). Hence, when we try sending packets with length > (hw-mtu - ethernet-fcs-size), the device port drops it and tx_errors_phy is incremented. Desired behavior is to catch these packets and drop them by the driver. Fix this behavior in XDP SQ allocation function (mlx5e_alloc_xdpsq) by subtracting ethernet FCS header size (4 Bytes) from current hw mtu value, since ethernet FCS is calculated and written to ethernet frames by the nic. Fixes: d8bec2b29a82 ("net/mlx5e: Support bpf_xdp_adjust_head()") Signed-off-by: Adham Faris Reviewed-by: Tariq Toukan Signed-off-by: Saeed Mahameed Signed-off-by: Sasha Levin --- drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index c1c4f38..be19f5c 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -977,7 +977,7 @@ static int mlx5e_alloc_xdpsq(struct mlx5e_channel *c, sq->channel = c; sq->uar_map = mdev->mlx5e_res.hw_objs.bfreg.map; sq->min_inline_mode = params->tx_min_inline_mode; - sq->hw_mtu = MLX5E_SW2HW_MTU(params, params->sw_mtu); + sq->hw_mtu = MLX5E_SW2HW_MTU(params, params->sw_mtu) - ETH_FCS_LEN; sq->xsk_pool = xsk_pool; sq->stats = sq->xsk_pool ? -- 2.7.4