[dpdk-dev] [PATCH v2] net/mlx5: set RSS key to NULL to indicate default RSS

[Ophir Munk <ophirmu@mellanox.com>]

Applications which add RSS rules must supply an RSS key and length.
If an application is only interested in default RSS operation it
should not care about the exact RSS key.
By setting the key to NULL - the PMD will use the default RSS key.
In addition if the application does not care about the RSS type it can
set it to 0 and the PMD will use the default type (ETH_RSS_IP).

Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
---
 doc/guides/nics/mlx5.rst           |  1 +
 drivers/net/mlx5/mlx5_flow.c       |  8 +++++++-
 drivers/net/mlx5/mlx5_flow_dv.c    |  8 ++++++--
 drivers/net/mlx5/mlx5_flow_verbs.c |  9 +++++++--
 drivers/net/mlx5/mlx5_rxq.c        | 14 ++++++--------
 lib/librte_ethdev/rte_flow.h       |  2 +-
 6 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index 6769628..de8f15b 100644
--- a/doc/guides/nics/mlx5.rst
+++ b/doc/guides/nics/mlx5.rst
@@ -54,6 +54,7 @@ Features
 - Support for scattered TX and RX frames.
 - IPv4, IPv6, TCPv4, TCPv6, UDPv4 and UDPv6 RSS on any number of queues.
 - Several RSS hash keys, one for each flow type.
+- NULL RSS key indicates default RSS key
 - Configurable RETA table.
 - Support for multiple MAC addresses.
 - VLAN filtering.
diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
index 280af0a..5742989 100644
--- a/drivers/net/mlx5/mlx5_flow.c
+++ b/drivers/net/mlx5/mlx5_flow.c
@@ -912,7 +912,13 @@ uint32_t mlx5_flow_adjust_priority(struct rte_eth_dev *dev, int32_t priority,
 					  RTE_FLOW_ERROR_TYPE_ACTION_CONF,
 					  &rss->level,
 					  "tunnel RSS is not supported");
-	if (rss->key_len < MLX5_RSS_HASH_KEY_LEN)
+	/* allow RSS key_len 0 in case of NULL (default) RSS key */
+	if (rss->key_len == 0 && rss->key != NULL)
+		return rte_flow_error_set(error, ENOTSUP,
+					  RTE_FLOW_ERROR_TYPE_ACTION_CONF,
+					  &rss->key_len,
+					  "RSS hash key length 0");
+	if (rss->key_len > 0 && rss->key_len < MLX5_RSS_HASH_KEY_LEN)
 		return rte_flow_error_set(error, ENOTSUP,
 					  RTE_FLOW_ERROR_TYPE_ACTION_CONF,
 					  &rss->key_len,
diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index 8f729f4..fd52bf4 100644
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -1056,6 +1056,7 @@
 {
 	const struct rte_flow_action_queue *queue;
 	const struct rte_flow_action_rss *rss;
+	uint8_t	*rss_key;
 	int actions_n = dev_flow->dv.actions_n;
 	struct rte_flow *flow = dev_flow->flow;
 
@@ -1094,8 +1095,11 @@
 			memcpy((*flow->queue), rss->queue,
 			       rss->queue_num * sizeof(uint16_t));
 		flow->rss.queue_num = rss->queue_num;
-		memcpy(flow->key, rss->key, MLX5_RSS_HASH_KEY_LEN);
-		flow->rss.types = rss->types;
+		/* NULL RSS key indicates default RSS key */
+		rss_key = (!rss->key) ? rss_hash_default_key : rss->key;
+		memcpy(flow->key, rss_key, MLX5_RSS_HASH_KEY_LEN);
+		/* RSS type 0 indicates default RSS type ETH_RSS_IP */
+		flow->rss.types = !rss->types ? ETH_RSS_IP : rss->types;
 		flow->rss.level = rss->level;
 		/* Added to array only in apply since we need the QP */
 		flow->actions |= MLX5_FLOW_ACTION_RSS;
diff --git a/drivers/net/mlx5/mlx5_flow_verbs.c b/drivers/net/mlx5/mlx5_flow_verbs.c
index 81bc39f..ae9042f 100644
--- a/drivers/net/mlx5/mlx5_flow_verbs.c
+++ b/drivers/net/mlx5/mlx5_flow_verbs.c
@@ -925,14 +925,19 @@
 				struct mlx5_flow *dev_flow)
 {
 	const struct rte_flow_action_rss *rss = action->conf;
+	const uint8_t *rss_key;
 	struct rte_flow *flow = dev_flow->flow;
 
 	if (flow->queue)
 		memcpy((*flow->queue), rss->queue,
 		       rss->queue_num * sizeof(uint16_t));
 	flow->rss.queue_num = rss->queue_num;
-	memcpy(flow->key, rss->key, MLX5_RSS_HASH_KEY_LEN);
-	flow->rss.types = rss->types;
+
+	/* NULL RSS key indicates default RSS key */
+	rss_key = !rss->key ? rss_hash_default_key : rss->key;
+	memcpy(flow->key, rss_key, MLX5_RSS_HASH_KEY_LEN);
+	/* RSS type 0 indicates default RSS type (ETH_RSS_IP) */
+	flow->rss.types = !rss->types ? ETH_RSS_IP : rss->types;
 	flow->rss.level = rss->level;
 	*action_flags |= MLX5_FLOW_ACTION_RSS;
 }
diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index ed993ea..36fc202 100644
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -1783,10 +1783,6 @@ struct mlx5_hrxq *
 		rte_errno = ENOMEM;
 		return NULL;
 	}
-	if (!rss_key_len) {
-		rss_key_len = MLX5_RSS_HASH_KEY_LEN;
-		rss_key = rss_hash_default_key;
-	}
 #ifdef HAVE_IBV_DEVICE_TUNNEL_SUPPORT
 	qp = mlx5_glue->dv_create_qp
 		(priv->ctx,
@@ -1798,8 +1794,7 @@ struct mlx5_hrxq *
 				IBV_QP_INIT_ATTR_RX_HASH,
 			.rx_hash_conf = (struct ibv_rx_hash_conf){
 				.rx_hash_function = IBV_RX_HASH_FUNC_TOEPLITZ,
-				.rx_hash_key_len = rss_key_len ? rss_key_len :
-						   MLX5_RSS_HASH_KEY_LEN,
+				.rx_hash_key_len = rss_key_len,
 				.rx_hash_key = rss_key ?
 					       (void *)(uintptr_t)rss_key :
 					       rss_hash_default_key,
@@ -1824,8 +1819,7 @@ struct mlx5_hrxq *
 				IBV_QP_INIT_ATTR_RX_HASH,
 			.rx_hash_conf = (struct ibv_rx_hash_conf){
 				.rx_hash_function = IBV_RX_HASH_FUNC_TOEPLITZ,
-				.rx_hash_key_len = rss_key_len ? rss_key_len :
-						   MLX5_RSS_HASH_KEY_LEN,
+				.rx_hash_key_len = rss_key_len,
 				.rx_hash_key = rss_key ?
 					       (void *)(uintptr_t)rss_key :
 					       rss_hash_default_key,
@@ -1888,8 +1882,12 @@ struct mlx5_hrxq *
 	LIST_FOREACH(hrxq, &priv->hrxqs, next) {
 		struct mlx5_ind_table_ibv *ind_tbl;
 
+		if (!rss_key_len)
+			rss_key_len = MLX5_RSS_HASH_KEY_LEN;
 		if (hrxq->rss_key_len != rss_key_len)
 			continue;
+		if (!rss_key)
+			rss_key = rss_hash_default_key;
 		if (memcmp(hrxq->rss_key, rss_key, rss_key_len))
 			continue;
 		if (hrxq->hash_fields != hash_fields)
diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
index c0fe879..6cc72ab 100644
--- a/lib/librte_ethdev/rte_flow.h
+++ b/lib/librte_ethdev/rte_flow.h
@@ -1785,7 +1785,7 @@ struct rte_flow_action_rss {
 	uint64_t types; /**< Specific RSS hash types (see ETH_RSS_*). */
 	uint32_t key_len; /**< Hash key length in bytes. */
 	uint32_t queue_num; /**< Number of entries in @p queue. */
-	const uint8_t *key; /**< Hash key. */
+	const uint8_t *key; /**< Hash key. NULL should indicate default key */
 	const uint16_t *queue; /**< Queue indices to use. */
 };
 
-- 
1.8.3.1