net/mlx5e: Add tc chains offload support for nic flows

Allow adding nic tc flow rules with goto chain action.

Connecting the nic flows to the mlx5 chains infrastructure in previous
patches allows us to support the creation of chained flow tables and
rules that direct to another chain for further packet processing.
This is a required preparation to support CT offloads for nic tc flows.

We allow the creation of 256 different chains for nic flows since we
have 8 bits available for the chain restore tag in case of a miss.
Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

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

@@ -1260,6 +1260,11 @@ static void mlx5e_handle_rx_cqe(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe)
 	}
 
 	mlx5e_complete_rx_cqe(rq, cqe, cqe_bcnt, skb);
+
+	if (mlx5e_cqe_regb_chain(cqe))
+		if (!mlx5e_tc_update_skb(cqe, skb))
+			goto free_wqe;
+
 	napi_gro_receive(rq->cq.napi, skb);
 
 free_wqe:
@@ -1521,6 +1526,11 @@ static void mlx5e_handle_rx_cqe_mpwrq(struct mlx5e_rq *rq, struct mlx5_cqe64 *cq
 		goto mpwrq_cqe_out;
 
 	mlx5e_complete_rx_cqe(rq, cqe, cqe_bcnt, skb);
+
+	if (mlx5e_cqe_regb_chain(cqe))
+		if (!mlx5e_tc_update_skb(cqe, skb))
+			goto mpwrq_cqe_out;
+
 	napi_gro_receive(rq->cq.napi, skb);
 
 mpwrq_cqe_out:

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

@@ -77,6 +77,9 @@ struct mlx5_flow_attr {
 	};
 };
 
+#define MLX5E_TC_TABLE_CHAIN_TAG_BITS 16
+#define MLX5E_TC_TABLE_CHAIN_TAG_MASK GENMASK(MLX5E_TC_TABLE_CHAIN_TAG_BITS - 1, 0)
+
 #if IS_ENABLED(CONFIG_MLX5_CLS_ACT)
 
 struct tunnel_match_key {
@@ -164,6 +167,7 @@ enum mlx5e_tc_attr_to_reg {
 	MARK_TO_REG,
 	LABELS_TO_REG,
 	FTEID_TO_REG,
+	NIC_CHAIN_TO_REG,
 };
 
 struct mlx5e_tc_attr_to_reg_mapping {
@@ -217,13 +221,16 @@ mlx5e_add_offloaded_nic_rule(struct mlx5e_priv *priv,
 			     struct mlx5_flow_spec *spec,
 			     struct mlx5_flow_attr *attr);
 void mlx5e_del_offloaded_nic_rule(struct mlx5e_priv *priv,
-				  struct mlx5_flow_handle *rule);
+				  struct mlx5_flow_handle *rule,
+				  struct mlx5_flow_attr *attr);
+
 #else /* CONFIG_MLX5_CLS_ACT */
 static inline int  mlx5e_tc_nic_init(struct mlx5e_priv *priv) { return 0; }
 static inline void mlx5e_tc_nic_cleanup(struct mlx5e_priv *priv) {}
 static inline int
 mlx5e_setup_tc_block_cb(enum tc_setup_type type, void *type_data, void *cb_priv)
 { return -EOPNOTSUPP; }
+
 #endif /* CONFIG_MLX5_CLS_ACT */
 
 struct mlx5_flow_attr *mlx5_alloc_flow_attr(enum mlx5_flow_namespace_type type);
@@ -242,4 +249,29 @@ mlx5e_setup_tc_block_cb(enum tc_setup_type type, void *type_data, void *cb_priv)
 { return -EOPNOTSUPP; }
 #endif
 
+#if IS_ENABLED(CONFIG_MLX5_CLS_ACT)
+static inline bool mlx5e_cqe_regb_chain(struct mlx5_cqe64 *cqe)
+{
+#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
+	u32 chain, reg_b;
+
+	reg_b = be32_to_cpu(cqe->ft_metadata);
+
+	chain = reg_b & MLX5E_TC_TABLE_CHAIN_TAG_MASK;
+	if (chain)
+		return true;
+#endif
+
+	return false;
+}
+
+bool mlx5e_tc_update_skb(struct mlx5_cqe64 *cqe, struct sk_buff *skb);
+#else /* CONFIG_MLX5_CLS_ACT */
+static inline bool mlx5e_cqe_regb_chain(struct mlx5_cqe64 *cqe)
+{ return false; }
+static inline bool
+mlx5e_tc_update_skb(struct mlx5_cqe64 *cqe, struct sk_buff *skb)
+{ return true; }
+#endif
+
 #endif /* __MLX5_EN_TC_H__ */

drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c

@@ -330,6 +330,12 @@ create_chain_restore(struct fs_chain *chain)
 			err = PTR_ERR(chain->restore_rule);
 			goto err_rule;
 		}
+	} else if (chains->ns == MLX5_FLOW_NAMESPACE_KERNEL) {
+		/* For NIC RX we don't need a restore rule
+		 * since we write the metadata to reg_b
+		 * that is passed to SW directly.
+		 */
+		chain_to_reg = NIC_CHAIN_TO_REG;
 	} else {
 		err = -EINVAL;
 		goto err_rule;
@@ -447,7 +453,10 @@ mlx5_chains_add_miss_rule(struct fs_chain *chain,
 	struct mlx5_flow_destination dest = {};
 	struct mlx5_flow_act act = {};
 
-	act.flags  = FLOW_ACT_IGNORE_FLOW_LEVEL | FLOW_ACT_NO_APPEND;
+	act.flags  = FLOW_ACT_NO_APPEND;
+	if (mlx5_chains_ignore_flow_level_supported(chain->chains))
+		act.flags |= FLOW_ACT_IGNORE_FLOW_LEVEL;
+
 	act.action = MLX5_FLOW_CONTEXT_ACTION_FWD_DEST;
 	dest.type  = MLX5_FLOW_DESTINATION_TYPE_FLOW_TABLE;
 	dest.ft = next_ft;