net/mlx5e: Set per priority hairpin pairs

As part of the QoS model, on xmit, the HW mandates that all packets going
through a given SQ have the same priority. To align hairpin SQs with that,
we use the priority given as part of the matching for the hairpin hash key.

This ensures that flows/packets mapped to different HW priorities will
go through different hairpin instances. If no priority is given for
matching, we treat that as an 8th priority, this is in order not to
harm cases where priority is specified.

Only the PCP priority trust model is supported.

Signed-off-by: Or Gerlitz <[email protected]>
Signed-off-by: Saeed Mahameed <[email protected]>

Author: ogerlitz

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

@@ -112,6 +112,7 @@ struct mlx5e_hairpin_entry {
 	struct list_head flows;
 
 	u16 peer_vhca_id;
+	u8 prio;
 	struct mlx5e_hairpin *hp;
 };
 
@@ -333,20 +334,63 @@ static void mlx5e_hairpin_destroy(struct mlx5e_hairpin *hp)
 	kvfree(hp);
 }
 
+static inline u32 hash_hairpin_info(u16 peer_vhca_id, u8 prio)
+{
+	return (peer_vhca_id << 16 | prio);
+}
+
 static struct mlx5e_hairpin_entry *mlx5e_hairpin_get(struct mlx5e_priv *priv,
-						     u16 peer_vhca_id)
+						     u16 peer_vhca_id, u8 prio)
 {
 	struct mlx5e_hairpin_entry *hpe;
+	u32 hash_key = hash_hairpin_info(peer_vhca_id, prio);
 
 	hash_for_each_possible(priv->fs.tc.hairpin_tbl, hpe,
-			       hairpin_hlist, peer_vhca_id) {
-		if (hpe->peer_vhca_id == peer_vhca_id)
+			       hairpin_hlist, hash_key) {
+		if (hpe->peer_vhca_id == peer_vhca_id && hpe->prio == prio)
 			return hpe;
 	}
 
 	return NULL;
 }
 
+#define UNKNOWN_MATCH_PRIO 8
+
+static int mlx5e_hairpin_get_prio(struct mlx5e_priv *priv,
+				  struct mlx5_flow_spec *spec, u8 *match_prio)
+{
+	void *headers_c, *headers_v;
+	u8 prio_val, prio_mask = 0;
+	bool vlan_present;
+
+#ifdef CONFIG_MLX5_CORE_EN_DCB
+	if (priv->dcbx_dp.trust_state != MLX5_QPTS_TRUST_PCP) {
+		netdev_warn(priv->netdev,
+			    "only PCP trust state supported for hairpin\n");
+		return -EOPNOTSUPP;
+	}
+#endif
+	headers_c = MLX5_ADDR_OF(fte_match_param, spec->match_criteria, outer_headers);
+	headers_v = MLX5_ADDR_OF(fte_match_param, spec->match_value, outer_headers);
+
+	vlan_present = MLX5_GET(fte_match_set_lyr_2_4, headers_v, cvlan_tag);
+	if (vlan_present) {
+		prio_mask = MLX5_GET(fte_match_set_lyr_2_4, headers_c, first_prio);
+		prio_val = MLX5_GET(fte_match_set_lyr_2_4, headers_v, first_prio);
+	}
+
+	if (!vlan_present || !prio_mask) {
+		prio_val = UNKNOWN_MATCH_PRIO;
+	} else if (prio_mask != 0x7) {
+		netdev_warn(priv->netdev,
+			    "masked priority match not supported for hairpin\n");
+		return -EOPNOTSUPP;
+	}
+
+	*match_prio = prio_val;
+	return 0;
+}
+
 static int mlx5e_hairpin_flow_add(struct mlx5e_priv *priv,
 				  struct mlx5e_tc_flow *flow,
 				  struct mlx5e_tc_flow_parse_attr *parse_attr)
@@ -356,6 +400,7 @@ static int mlx5e_hairpin_flow_add(struct mlx5e_priv *priv,
 	struct mlx5_core_dev *peer_mdev;
 	struct mlx5e_hairpin_entry *hpe;
 	struct mlx5e_hairpin *hp;
+	u8 match_prio;
 	u16 peer_id;
 	int err;
 
@@ -366,7 +411,10 @@ static int mlx5e_hairpin_flow_add(struct mlx5e_priv *priv,
 	}
 
 	peer_id = MLX5_CAP_GEN(peer_mdev, vhca_id);
-	hpe = mlx5e_hairpin_get(priv, peer_id);
+	err = mlx5e_hairpin_get_prio(priv, &parse_attr->spec, &match_prio);
+	if (err)
+		return err;
+	hpe = mlx5e_hairpin_get(priv, peer_id, match_prio);
 	if (hpe)
 		goto attach_flow;
 
@@ -376,6 +424,7 @@ static int mlx5e_hairpin_flow_add(struct mlx5e_priv *priv,
 
 	INIT_LIST_HEAD(&hpe->flows);
 	hpe->peer_vhca_id = peer_id;
+	hpe->prio = match_prio;
 
 	params.log_data_size = 15;
 	params.log_data_size = min_t(u8, params.log_data_size,
@@ -390,12 +439,13 @@ static int mlx5e_hairpin_flow_add(struct mlx5e_priv *priv,
 		goto create_hairpin_err;
 	}
 
-	netdev_dbg(priv->netdev, "add hairpin: tirn %x rqn %x peer %s sqn %x log data size %d\n",
+	netdev_dbg(priv->netdev, "add hairpin: tirn %x rqn %x peer %s sqn %x prio %d log data size %d\n",
 		   hp->tirn, hp->pair->rqn, hp->pair->peer_mdev->priv.name,
-		   hp->pair->sqn, params.log_data_size);
+		   hp->pair->sqn, match_prio, params.log_data_size);
 
 	hpe->hp = hp;
-	hash_add(priv->fs.tc.hairpin_tbl, &hpe->hairpin_hlist, peer_id);
+	hash_add(priv->fs.tc.hairpin_tbl, &hpe->hairpin_hlist,
+		 hash_hairpin_info(peer_id, match_prio));
 
 attach_flow:
 	flow->nic_attr->hairpin_tirn = hpe->hp->tirn;