net/mlx5e: Add trap entity to ETH driver

Introduce mlx5e_trap which includes a dedicated RQ and NAPI for trapped
packets. Trap-RQ processes packets that were destined to be dropped,
but for debug and visibility sake these packets are trapped and reported
to devlink.
Trap-RQ connects between the HW and the driver and is not a part of a
channel. Open mlx5e_create_rq() and mlx5_core_destroy_rq() as API and
add dedicate RQ handlers which report to devlink of trapped packets.
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlx5/core/Makefile

@@ -27,7 +27,7 @@ mlx5_core-$(CONFIG_MLX5_CORE_EN) += en_main.o en_common.o en_fs.o en_ethtool.o \
 		en_selftest.o en/port.o en/monitor_stats.o en/health.o \
 		en/reporter_tx.o en/reporter_rx.o en/params.o en/xsk/pool.o \
 		en/xsk/setup.o en/xsk/rx.o en/xsk/tx.o en/devlink.o en/ptp.o \
-		en/qos.o
+		en/qos.o en/trap.o
 
 #
 # Netdev extra

drivers/net/ethernet/mellanox/mlx5/core/en.h

@@ -564,6 +564,7 @@ typedef bool (*mlx5e_fp_post_rx_wqes)(struct mlx5e_rq *rq);
 typedef void (*mlx5e_fp_dealloc_wqe)(struct mlx5e_rq*, u16);
 
 int mlx5e_rq_set_handlers(struct mlx5e_rq *rq, struct mlx5e_params *params, bool xsk);
+void mlx5e_rq_set_trap_handlers(struct mlx5e_rq *rq, struct mlx5e_params *params);
 
 enum mlx5e_rq_flag {
 	MLX5E_RQ_FLAG_XDP_XMIT,
@@ -805,6 +806,8 @@ struct mlx5e_htb {
 	u16 defcls;
 };
 
+struct mlx5e_trap;
+
 struct mlx5e_priv {
 	/* priv data path fields - start */
 	/* +1 for port ptp ts */
@@ -844,8 +847,10 @@ struct mlx5e_priv {
 
 	struct mlx5_core_dev      *mdev;
 	struct net_device         *netdev;
+	struct mlx5e_trap         *en_trap;
 	struct mlx5e_stats         stats;
 	struct mlx5e_channel_stats channel_stats[MLX5E_MAX_NUM_CHANNELS];
+	struct mlx5e_channel_stats trap_stats;
 	struct mlx5e_port_ptp_stats port_ptp_stats;
 	u16                        max_nch;
 	u8                         max_opened_tc;
@@ -961,6 +966,8 @@ int mlx5e_open_rq(struct mlx5e_channel *c, struct mlx5e_params *params,
 int mlx5e_wait_for_min_rx_wqes(struct mlx5e_rq *rq, int wait_time);
 void mlx5e_deactivate_rq(struct mlx5e_rq *rq);
 void mlx5e_close_rq(struct mlx5e_rq *rq);
+int mlx5e_create_rq(struct mlx5e_rq *rq, struct mlx5e_rq_param *param);
+void mlx5e_destroy_rq(struct mlx5e_rq *rq);
 
 struct mlx5e_sq_param;
 int mlx5e_open_icosq(struct mlx5e_channel *c, struct mlx5e_params *params,

drivers/net/ethernet/mellanox/mlx5/core/en/trap.h

+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/* Copyright (c) 2020, Mellanox Technologies */
+
+#ifndef __MLX5E_TRAP_H__
+#define __MLX5E_TRAP_H__
+
+#include "../en.h"
+#include "../devlink.h"
+
+struct mlx5e_trap {
+	/* data path */
+	struct mlx5e_rq            rq;
+	struct mlx5e_tir           tir;
+	struct napi_struct         napi;
+	struct device             *pdev;
+	struct net_device         *netdev;
+	__be32                     mkey_be;
+
+	/* data path - accessed per napi poll */
+	struct mlx5e_ch_stats     *stats;
+
+	/* control */
+	struct mlx5e_priv         *priv;
+	struct mlx5_core_dev      *mdev;
+	struct hwtstamp_config    *tstamp;
+	DECLARE_BITMAP(state, MLX5E_CHANNEL_NUM_STATES);
+
+	struct mlx5e_params        params;
+	struct mlx5e_rq_param      rq_param;
+};
+
+void mlx5e_close_trap(struct mlx5e_trap *trap);
+void mlx5e_deactivate_trap(struct mlx5e_priv *priv);
+int mlx5e_handle_trap_event(struct mlx5e_priv *priv, struct mlx5_trap_ctx *trap_ctx);
+#endif

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

@@ -649,8 +649,7 @@ static void mlx5e_free_rq(struct mlx5e_rq *rq)
 	mlx5_wq_destroy(&rq->wq_ctrl);
 }
 
-static int mlx5e_create_rq(struct mlx5e_rq *rq,
-			   struct mlx5e_rq_param *param)
+int mlx5e_create_rq(struct mlx5e_rq *rq, struct mlx5e_rq_param *param)
 {
 	struct mlx5_core_dev *mdev = rq->mdev;
 
@@ -773,7 +772,7 @@ static int mlx5e_modify_rq_vsd(struct mlx5e_rq *rq, bool vsd)
 	return err;
 }
 
-static void mlx5e_destroy_rq(struct mlx5e_rq *rq)
+void mlx5e_destroy_rq(struct mlx5e_rq *rq)
 {
 	mlx5_core_destroy_rq(rq->mdev, rq->rqn);
 }

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

@@ -52,6 +52,7 @@
 #include "en/xsk/rx.h"
 #include "en/health.h"
 #include "en/params.h"
+#include "devlink.h"
 
 static struct sk_buff *
 mlx5e_skb_from_cqe_mpwrq_linear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *wi,
@@ -1815,3 +1816,48 @@ int mlx5e_rq_set_handlers(struct mlx5e_rq *rq, struct mlx5e_params *params, bool
 
 	return 0;
 }
+
+static void mlx5e_trap_handle_rx_cqe(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe)
+{
+	struct mlx5e_priv *priv = netdev_priv(rq->netdev);
+	struct mlx5_wq_cyc *wq = &rq->wqe.wq;
+	struct mlx5e_wqe_frag_info *wi;
+	struct sk_buff *skb;
+	u32 cqe_bcnt;
+	u16 trap_id;
+	u16 ci;
+
+	trap_id  = get_cqe_flow_tag(cqe);
+	ci       = mlx5_wq_cyc_ctr2ix(wq, be16_to_cpu(cqe->wqe_counter));
+	wi       = get_frag(rq, ci);
+	cqe_bcnt = be32_to_cpu(cqe->byte_cnt);
+
+	if (unlikely(MLX5E_RX_ERR_CQE(cqe))) {
+		rq->stats->wqe_err++;
+		goto free_wqe;
+	}
+
+	skb = mlx5e_skb_from_cqe_nonlinear(rq, cqe, wi, cqe_bcnt);
+	if (!skb)
+		goto free_wqe;
+
+	mlx5e_complete_rx_cqe(rq, cqe, cqe_bcnt, skb);
+	skb_push(skb, ETH_HLEN);
+
+	mlx5_devlink_trap_report(rq->mdev, trap_id, skb, &priv->dl_port);
+	dev_kfree_skb_any(skb);
+
+free_wqe:
+	mlx5e_free_rx_wqe(rq, wi, false);
+	mlx5_wq_cyc_pop(wq);
+}
+
+void mlx5e_rq_set_trap_handlers(struct mlx5e_rq *rq, struct mlx5e_params *params)
+{
+	rq->wqe.skb_from_cqe = mlx5e_rx_is_linear_skb(params, NULL) ?
+			       mlx5e_skb_from_cqe_linear :
+			       mlx5e_skb_from_cqe_nonlinear;
+	rq->post_wqes = mlx5e_post_rx_wqes;
+	rq->dealloc_wqe = mlx5e_dealloc_rx_wqe;
+	rq->handle_rx_cqe = mlx5e_trap_handle_rx_cqe;
+}

include/linux/mlx5/device.h

@@ -903,6 +903,11 @@ static inline u64 get_cqe_ts(struct mlx5_cqe64 *cqe)
 	return (u64)lo | ((u64)hi << 32);
 }
 
+static inline u16 get_cqe_flow_tag(struct mlx5_cqe64 *cqe)
+{
+	return be32_to_cpu(cqe->sop_drop_qpn) & 0xFFF;
+}
+
 #define MLX5_MPWQE_LOG_NUM_STRIDES_BASE	(9)
 #define MLX5_MPWQE_LOG_STRIDE_SZ_BASE	(6)