Merge branch 'net-mlx5e-ct-add-support-for-hardware-steering'

Tariq Toukan says:

====================
net/mlx5e: CT: Add support for hardware steering

This series start with one more HWS patch by Yevgeny, followed by
patches that add support for connection tracking in hardware steering
mode. It consists of:
- patch Rust-for-Linux#2 hooks up the CT ops for the new mode in the right places.
- patch Rust-for-Linux#3 moves a function into a common file, so it can be reused.
- patch Rust-for-Linux#4 uses the HWS API to implement connection tracking.

The main advantage of hardware steering compared to software steering is
vastly improved performance when adding/removing/updating rules.  Using
the T-Rex traffic generator to initiate multi-million UDP flows per
second, a kernel running with these patches was able to offload ~600K
unique UDP flows per second, a number around ~7x larger than software
steering was able to achieve on the same hardware (256-thread AMD EPYC,
512 GB RAM, ConnectX 7 b2b).
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

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

@@ -60,6 +60,7 @@ mlx5_core-$(CONFIG_MLX5_CLS_ACT)     += en/tc/act/act.o en/tc/act/drop.o en/tc/a
 ifneq ($(CONFIG_MLX5_TC_CT),)
 	mlx5_core-y			     += en/tc_ct.o en/tc/ct_fs_dmfs.o
 	mlx5_core-$(CONFIG_MLX5_SW_STEERING) += en/tc/ct_fs_smfs.o
+	mlx5_core-$(CONFIG_MLX5_HW_STEERING) += en/tc/ct_fs_hmfs.o
 endif
 
 mlx5_core-$(CONFIG_MLX5_TC_SAMPLE)   += en/tc/sample.o

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

@@ -48,4 +48,14 @@ mlx5_ct_fs_smfs_ops_get(void)
 }
 #endif /* IS_ENABLED(CONFIG_MLX5_SW_STEERING) */
 
+#if IS_ENABLED(CONFIG_MLX5_HW_STEERING)
+struct mlx5_ct_fs_ops *mlx5_ct_fs_hmfs_ops_get(void);
+#else
+static inline struct mlx5_ct_fs_ops *
+mlx5_ct_fs_hmfs_ops_get(void)
+{
+	return NULL;
+}
+#endif /* IS_ENABLED(CONFIG_MLX5_SW_STEERING) */
+
 #endif /* __MLX5_EN_TC_CT_FS_H__ */

drivers/net/ethernet/mellanox/mlx5/core/en/tc/ct_fs_hmfs.c

@@ -0,0 +1,292 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/* Copyright (c) 2025, NVIDIA CORPORATION & AFFILIATES. */
+
+#include "en_tc.h"
+#include "en/tc_ct.h"
+#include "en/tc_priv.h"
+#include "en/tc/ct_fs.h"
+#include "fs_core.h"
+#include "steering/hws/fs_hws_pools.h"
+#include "steering/hws/mlx5hws.h"
+#include "steering/hws/table.h"
+
+struct mlx5_ct_fs_hmfs_matcher {
+	struct mlx5hws_bwc_matcher *hws_bwc_matcher;
+	refcount_t ref;
+};
+
+/* We need {ipv4, ipv6} x {tcp, udp, gre}  matchers. */
+#define NUM_MATCHERS (2 * 3)
+
+struct mlx5_ct_fs_hmfs {
+	struct mlx5hws_table *ct_tbl;
+	struct mlx5hws_table *ct_nat_tbl;
+	struct mlx5_flow_table *ct_nat;
+	struct mlx5hws_action *fwd_action;
+	struct mlx5hws_action *last_action;
+	struct mlx5hws_context *ctx;
+	struct mutex lock;   /* Guards matchers */
+	struct mlx5_ct_fs_hmfs_matcher matchers[NUM_MATCHERS];
+	struct mlx5_ct_fs_hmfs_matcher matchers_nat[NUM_MATCHERS];
+};
+
+struct mlx5_ct_fs_hmfs_rule {
+	struct mlx5_ct_fs_rule fs_rule;
+	struct mlx5hws_bwc_rule *hws_bwc_rule;
+	struct mlx5_ct_fs_hmfs_matcher *hmfs_matcher;
+	struct mlx5_fc *counter;
+};
+
+static u32 get_matcher_idx(bool ipv4, bool tcp, bool gre)
+{
+	return ipv4 * 3 + tcp * 2 + gre;
+}
+
+static int mlx5_ct_fs_hmfs_init(struct mlx5_ct_fs *fs, struct mlx5_flow_table *ct,
+				struct mlx5_flow_table *ct_nat, struct mlx5_flow_table *post_ct)
+{
+	u32 flags = MLX5HWS_ACTION_FLAG_HWS_FDB | MLX5HWS_ACTION_FLAG_SHARED;
+	struct mlx5hws_table *ct_tbl, *ct_nat_tbl, *post_ct_tbl;
+	struct mlx5_ct_fs_hmfs *fs_hmfs = mlx5_ct_fs_priv(fs);
+
+	ct_tbl = ct->fs_hws_table.hws_table;
+	ct_nat_tbl = ct_nat->fs_hws_table.hws_table;
+	post_ct_tbl = post_ct->fs_hws_table.hws_table;
+	fs_hmfs->ct_nat = ct_nat;
+
+	if (!ct_tbl || !ct_nat_tbl || !post_ct_tbl) {
+		netdev_warn(fs->netdev, "ct_fs_hmfs: failed to init, missing backing hws tables");
+		return -EOPNOTSUPP;
+	}
+
+	netdev_dbg(fs->netdev, "using hmfs steering");
+
+	fs_hmfs->ct_tbl = ct_tbl;
+	fs_hmfs->ct_nat_tbl = ct_nat_tbl;
+	fs_hmfs->ctx = ct_tbl->ctx;
+	mutex_init(&fs_hmfs->lock);
+
+	fs_hmfs->fwd_action = mlx5hws_action_create_dest_table(ct_tbl->ctx, post_ct_tbl, flags);
+	if (!fs_hmfs->fwd_action) {
+		netdev_warn(fs->netdev, "ct_fs_hmfs: failed to create fwd action\n");
+		return -EINVAL;
+	}
+	fs_hmfs->last_action = mlx5hws_action_create_last(ct_tbl->ctx, flags);
+	if (!fs_hmfs->last_action) {
+		netdev_warn(fs->netdev, "ct_fs_hmfs: failed to create last action\n");
+		mlx5hws_action_destroy(fs_hmfs->fwd_action);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void mlx5_ct_fs_hmfs_destroy(struct mlx5_ct_fs *fs)
+{
+	struct mlx5_ct_fs_hmfs *fs_hmfs = mlx5_ct_fs_priv(fs);
+
+	mlx5hws_action_destroy(fs_hmfs->last_action);
+	mlx5hws_action_destroy(fs_hmfs->fwd_action);
+}
+
+static struct mlx5hws_bwc_matcher *
+mlx5_ct_fs_hmfs_matcher_create(struct mlx5_ct_fs *fs, struct mlx5hws_table *tbl,
+			       struct mlx5_flow_spec *spec, bool ipv4, bool tcp, bool gre)
+{
+	u8 match_criteria_enable = MLX5_MATCH_MISC_PARAMETERS_2 | MLX5_MATCH_OUTER_HEADERS;
+	struct mlx5hws_match_parameters mask = {
+		.match_buf = spec->match_criteria,
+		.match_sz = sizeof(spec->match_criteria),
+	};
+	u32 priority = get_matcher_idx(ipv4, tcp, gre);  /* Static priority based on params. */
+	struct mlx5hws_bwc_matcher *hws_bwc_matcher;
+
+	hws_bwc_matcher = mlx5hws_bwc_matcher_create(tbl, priority, match_criteria_enable, &mask);
+	if (!hws_bwc_matcher)
+		return ERR_PTR(-EINVAL);
+
+	return hws_bwc_matcher;
+}
+
+static struct mlx5_ct_fs_hmfs_matcher *
+mlx5_ct_fs_hmfs_matcher_get(struct mlx5_ct_fs *fs, struct mlx5_flow_spec *spec,
+			    bool nat, bool ipv4, bool tcp, bool gre)
+{
+	struct mlx5_ct_fs_hmfs *fs_hmfs = mlx5_ct_fs_priv(fs);
+	u32 matcher_idx = get_matcher_idx(ipv4, tcp, gre);
+	struct mlx5_ct_fs_hmfs_matcher *hmfs_matcher;
+	struct mlx5hws_bwc_matcher *hws_bwc_matcher;
+	struct mlx5hws_table *tbl;
+
+	hmfs_matcher = nat ?
+		(fs_hmfs->matchers_nat + matcher_idx) :
+		(fs_hmfs->matchers + matcher_idx);
+
+	if (refcount_inc_not_zero(&hmfs_matcher->ref))
+		return hmfs_matcher;
+
+	mutex_lock(&fs_hmfs->lock);
+
+	/* Retry with lock, as the matcher might be already created by another cpu. */
+	if (refcount_inc_not_zero(&hmfs_matcher->ref))
+		goto out_unlock;
+
+	tbl = nat ? fs_hmfs->ct_nat_tbl : fs_hmfs->ct_tbl;
+
+	hws_bwc_matcher = mlx5_ct_fs_hmfs_matcher_create(fs, tbl, spec, ipv4, tcp, gre);
+	if (IS_ERR(hws_bwc_matcher)) {
+		netdev_warn(fs->netdev,
+			    "ct_fs_hmfs: failed to create bwc matcher (nat %d, ipv4 %d, tcp %d, gre %d), err: %ld\n",
+			    nat, ipv4, tcp, gre, PTR_ERR(hws_bwc_matcher));
+
+		hmfs_matcher = ERR_CAST(hws_bwc_matcher);
+		goto out_unlock;
+	}
+
+	hmfs_matcher->hws_bwc_matcher = hws_bwc_matcher;
+	refcount_set(&hmfs_matcher->ref, 1);
+
+out_unlock:
+	mutex_unlock(&fs_hmfs->lock);
+	return hmfs_matcher;
+}
+
+static void
+mlx5_ct_fs_hmfs_matcher_put(struct mlx5_ct_fs *fs, struct mlx5_ct_fs_hmfs_matcher *hmfs_matcher)
+{
+	struct mlx5_ct_fs_hmfs *fs_hmfs = mlx5_ct_fs_priv(fs);
+
+	if (!refcount_dec_and_mutex_lock(&hmfs_matcher->ref, &fs_hmfs->lock))
+		return;
+
+	mlx5hws_bwc_matcher_destroy(hmfs_matcher->hws_bwc_matcher);
+	mutex_unlock(&fs_hmfs->lock);
+}
+
+#define NUM_CT_HMFS_RULES 4
+
+static void mlx5_ct_fs_hmfs_fill_rule_actions(struct mlx5_ct_fs_hmfs *fs_hmfs,
+					      struct mlx5_flow_attr *attr,
+					      struct mlx5hws_rule_action *rule_actions)
+{
+	struct mlx5_fs_hws_action *mh_action = &attr->modify_hdr->fs_hws_action;
+
+	memset(rule_actions, 0, NUM_CT_HMFS_RULES * sizeof(*rule_actions));
+	rule_actions[0].action = mlx5_fc_get_hws_action(fs_hmfs->ctx, attr->counter);
+	/* Modify header is special, it may require extra arguments outside the action itself. */
+	if (mh_action->mh_data) {
+		rule_actions[1].modify_header.offset = mh_action->mh_data->offset;
+		rule_actions[1].modify_header.data = mh_action->mh_data->data;
+	}
+	rule_actions[1].action = mh_action->hws_action;
+	rule_actions[2].action = fs_hmfs->fwd_action;
+	rule_actions[3].action = fs_hmfs->last_action;
+}
+
+static struct mlx5_ct_fs_rule *
+mlx5_ct_fs_hmfs_ct_rule_add(struct mlx5_ct_fs *fs, struct mlx5_flow_spec *spec,
+			    struct mlx5_flow_attr *attr, struct flow_rule *flow_rule)
+{
+	struct mlx5hws_rule_action rule_actions[NUM_CT_HMFS_RULES];
+	struct mlx5_ct_fs_hmfs *fs_hmfs = mlx5_ct_fs_priv(fs);
+	struct mlx5hws_match_parameters match_params = {
+		.match_buf = spec->match_value,
+		.match_sz = ARRAY_SIZE(spec->match_value),
+	};
+	struct mlx5_ct_fs_hmfs_matcher *hmfs_matcher;
+	struct mlx5_ct_fs_hmfs_rule *hmfs_rule;
+	bool nat, tcp, ipv4, gre;
+	int err;
+
+	if (!mlx5e_tc_ct_is_valid_flow_rule(fs->netdev, flow_rule))
+		return ERR_PTR(-EOPNOTSUPP);
+
+	hmfs_rule = kzalloc(sizeof(*hmfs_rule), GFP_KERNEL);
+	if (!hmfs_rule)
+		return ERR_PTR(-ENOMEM);
+
+	nat = (attr->ft == fs_hmfs->ct_nat);
+	ipv4 = mlx5e_tc_get_ip_version(spec, true) == 4;
+	tcp = MLX5_GET(fte_match_param, spec->match_value,
+		       outer_headers.ip_protocol) == IPPROTO_TCP;
+	gre = MLX5_GET(fte_match_param, spec->match_value,
+		       outer_headers.ip_protocol) == IPPROTO_GRE;
+
+	hmfs_matcher = mlx5_ct_fs_hmfs_matcher_get(fs, spec, nat, ipv4, tcp, gre);
+	if (IS_ERR(hmfs_matcher)) {
+		err = PTR_ERR(hmfs_matcher);
+		goto err_free_rule;
+	}
+	hmfs_rule->hmfs_matcher = hmfs_matcher;
+
+	mlx5_ct_fs_hmfs_fill_rule_actions(fs_hmfs, attr, rule_actions);
+	hmfs_rule->counter = attr->counter;
+
+	hmfs_rule->hws_bwc_rule =
+		mlx5hws_bwc_rule_create(hmfs_matcher->hws_bwc_matcher, &match_params,
+					spec->flow_context.flow_source, rule_actions);
+	if (!hmfs_rule->hws_bwc_rule) {
+		err = -EINVAL;
+		goto err_put_matcher;
+	}
+
+	return &hmfs_rule->fs_rule;
+
+err_put_matcher:
+	mlx5_fc_put_hws_action(hmfs_rule->counter);
+	mlx5_ct_fs_hmfs_matcher_put(fs, hmfs_matcher);
+err_free_rule:
+	kfree(hmfs_rule);
+	return ERR_PTR(err);
+}
+
+static void mlx5_ct_fs_hmfs_ct_rule_del(struct mlx5_ct_fs *fs, struct mlx5_ct_fs_rule *fs_rule)
+{
+	struct mlx5_ct_fs_hmfs_rule *hmfs_rule = container_of(fs_rule,
+							      struct mlx5_ct_fs_hmfs_rule,
+							      fs_rule);
+	mlx5hws_bwc_rule_destroy(hmfs_rule->hws_bwc_rule);
+	mlx5_fc_put_hws_action(hmfs_rule->counter);
+	mlx5_ct_fs_hmfs_matcher_put(fs, hmfs_rule->hmfs_matcher);
+	kfree(hmfs_rule);
+}
+
+static int mlx5_ct_fs_hmfs_ct_rule_update(struct mlx5_ct_fs *fs, struct mlx5_ct_fs_rule *fs_rule,
+					  struct mlx5_flow_spec *spec, struct mlx5_flow_attr *attr)
+{
+	struct mlx5_ct_fs_hmfs_rule *hmfs_rule = container_of(fs_rule,
+							      struct mlx5_ct_fs_hmfs_rule,
+							      fs_rule);
+	struct mlx5hws_rule_action rule_actions[NUM_CT_HMFS_RULES];
+	struct mlx5_ct_fs_hmfs *fs_hmfs = mlx5_ct_fs_priv(fs);
+	int err;
+
+	mlx5_ct_fs_hmfs_fill_rule_actions(fs_hmfs, attr, rule_actions);
+
+	err = mlx5hws_bwc_rule_action_update(hmfs_rule->hws_bwc_rule, rule_actions);
+	if (err) {
+		mlx5_fc_put_hws_action(attr->counter);
+		return err;
+	}
+
+	mlx5_fc_put_hws_action(hmfs_rule->counter);
+	hmfs_rule->counter = attr->counter;
+
+	return 0;
+}
+
+static struct mlx5_ct_fs_ops hmfs_ops = {
+	.ct_rule_add = mlx5_ct_fs_hmfs_ct_rule_add,
+	.ct_rule_del = mlx5_ct_fs_hmfs_ct_rule_del,
+	.ct_rule_update = mlx5_ct_fs_hmfs_ct_rule_update,
+
+	.init = mlx5_ct_fs_hmfs_init,
+	.destroy = mlx5_ct_fs_hmfs_destroy,
+
+	.priv_size = sizeof(struct mlx5_ct_fs_hmfs),
+};
+
+struct mlx5_ct_fs_ops *mlx5_ct_fs_hmfs_ops_get(void)
+{
+	return &hmfs_ops;
+}