net/mlx5: implement tunnel offload

Tunnel Offload API provides hardware independent, unified model
to offload tunneled traffic. Key model elements are:
 - apply matches to both outer and inner packet headers
   during entire offload procedure;
 - restore outer header of partially offloaded packet;
 - model is implemented as a set of helper functions.

Implementation details:
* tunnel_offload PMD parameter must be set to 1 to enable the feature.
* application cannot use MARK and META flow actions with tunnel.
* offload JUMP action is restricted to steering tunnel rule only.

Signed-off-by: Gregory Etelson <getelson@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

doc/guides/nics/mlx5.rst

@@ -787,6 +787,9 @@ Driver options
     24 bits. The actual supported width can be retrieved in runtime by
     series of rte_flow_validate() trials.
 
+  - 3, this engages tunnel offload mode. In E-Switch configuration, that
+    mode implicitly activates ``dv_xmeta_en=1``.
+
   +------+-----------+-----------+-------------+-------------+
   | Mode | ``MARK``  | ``META``  | ``META`` Tx | FDB/Through |
   +======+===========+===========+=============+=============+

drivers/net/mlx5/linux/mlx5_os.c

@@ -291,6 +291,12 @@ mlx5_alloc_shared_dr(struct mlx5_priv *priv)
 		sh->esw_drop_action = mlx5_glue->dr_create_flow_action_drop();
 	}
 #endif
+	if (!sh->tunnel_hub)
+		err = mlx5_alloc_tunnel_hub(sh);
+	if (err) {
+		DRV_LOG(ERR, "mlx5_alloc_tunnel_hub failed err=%d", err);
+		goto error;
+	}
 	if (priv->config.reclaim_mode == MLX5_RCM_AGGR) {
 		mlx5_glue->dr_reclaim_domain_memory(sh->rx_domain, 1);
 		mlx5_glue->dr_reclaim_domain_memory(sh->tx_domain, 1);
@@ -335,6 +341,10 @@ mlx5_alloc_shared_dr(struct mlx5_priv *priv)
 		mlx5_hlist_destroy(sh->tag_table, NULL, NULL);
 		sh->tag_table = NULL;
 	}
+	if (sh->tunnel_hub) {
+		mlx5_release_tunnel_hub(sh, priv->dev_port);
+		sh->tunnel_hub = NULL;
+	}
 	mlx5_free_table_hash_list(priv);
 	return err;
 }
@@ -391,6 +401,10 @@ mlx5_os_free_shared_dr(struct mlx5_priv *priv)
 		mlx5_hlist_destroy(sh->tag_table, NULL, NULL);
 		sh->tag_table = NULL;
 	}
+	if (sh->tunnel_hub) {
+		mlx5_release_tunnel_hub(sh, priv->dev_port);
+		sh->tunnel_hub = NULL;
+	}
 	mlx5_free_table_hash_list(priv);
 }
 
@@ -733,6 +747,10 @@ mlx5_dev_spawn(struct rte_device *dpdk_dev,
 			strerror(rte_errno));
 		goto error;
 	}
+	if (config->dv_miss_info) {
+		if (switch_info->master || switch_info->representor)
+			config->dv_xmeta_en = MLX5_XMETA_MODE_META16;
+	}
 	mlx5_malloc_mem_select(config->sys_mem_en);
 	sh = mlx5_alloc_shared_dev_ctx(spawn, config);
 	if (!sh)

drivers/net/mlx5/mlx5.c

@@ -1619,13 +1619,17 @@ mlx5_args_check(const char *key, const char *val, void *opaque)
 	} else if (strcmp(MLX5_DV_XMETA_EN, key) == 0) {
 		if (tmp != MLX5_XMETA_MODE_LEGACY &&
 		    tmp != MLX5_XMETA_MODE_META16 &&
-		    tmp != MLX5_XMETA_MODE_META32) {
+		    tmp != MLX5_XMETA_MODE_META32 &&
+		    tmp != MLX5_XMETA_MODE_MISS_INFO) {
 			DRV_LOG(ERR, "invalid extensive "
 				     "metadata parameter");
 			rte_errno = EINVAL;
 			return -rte_errno;
 		}
-		config->dv_xmeta_en = tmp;
+		if (tmp != MLX5_XMETA_MODE_MISS_INFO)
+			config->dv_xmeta_en = tmp;
+		else
+			config->dv_miss_info = 1;
 	} else if (strcmp(MLX5_LACP_BY_USER, key) == 0) {
 		config->lacp_by_user = !!tmp;
 	} else if (strcmp(MLX5_MR_EXT_MEMSEG_EN, key) == 0) {

drivers/net/mlx5/mlx5.h

@@ -208,6 +208,7 @@ struct mlx5_dev_config {
 	unsigned int rt_timestamp:1; /* realtime timestamp format. */
 	unsigned int sys_mem_en:1; /* The default memory allocator. */
 	unsigned int decap_en:1; /* Whether decap will be used or not. */
+	unsigned int dv_miss_info:1; /* restore packet after partial hw miss */
 	struct {
 		unsigned int enabled:1; /* Whether MPRQ is enabled. */
 		unsigned int stride_num_n; /* Number of strides. */
@@ -644,6 +645,7 @@ struct mlx5_dev_ctx_shared {
 	/* UAR same-page access control required in 32bit implementations. */
 #endif
 	struct mlx5_hlist *flow_tbls;
+	struct mlx5_flow_tunnel_hub *tunnel_hub;
 	/* Direct Rules tables for FDB, NIC TX+RX */
 	void *esw_drop_action; /* Pointer to DR E-Switch drop action. */
 	void *pop_vlan_action; /* Pointer to DR pop VLAN action. */

drivers/net/mlx5/mlx5_defs.h

@@ -165,6 +165,8 @@
 #define MLX5_XMETA_MODE_LEGACY 0
 #define MLX5_XMETA_MODE_META16 1
 #define MLX5_XMETA_MODE_META32 2
+/* Provide info on patrial hw miss. Implies MLX5_XMETA_MODE_META16 */
+#define MLX5_XMETA_MODE_MISS_INFO 3
 
 /* MLX5_TX_DB_NC supported values. */
 #define MLX5_TXDB_CACHED 0