ethdev: add mbuf RSS update as an offload

Add new Rx offload flag `DEV_RX_OFFLOAD_RSS_HASH` which can be used to
enable/disable PMDs write to `rte_mbuf:#️⃣:rss`.
PMDs notify the validity of `rte_mbuf:#️⃣rss` to the application
by enabling `PKT_RX_RSS_HASH ` flag in `rte_mbuf::ol_flags`.

Also update testpmd rx_offload command to include RSS_HASH

Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>

app/test-pmd/cmdline.c

@@ -18084,7 +18084,7 @@ cmdline_parse_token_string_t cmd_config_per_port_rx_offload_result_offload =
 		 offload, "vlan_strip#ipv4_cksum#udp_cksum#tcp_cksum#tcp_lro#"
 			   "qinq_strip#outer_ipv4_cksum#macsec_strip#"
 			   "header_split#vlan_filter#vlan_extend#jumbo_frame#"
-			   "scatter#timestamp#security#keep_crc");
+			   "scatter#timestamp#security#keep_crc#rss_hash");
 cmdline_parse_token_string_t cmd_config_per_port_rx_offload_result_on_off =
 	TOKEN_STRING_INITIALIZER
 		(struct cmd_config_per_port_rx_offload_result,
@@ -18164,7 +18164,7 @@ cmdline_parse_inst_t cmd_config_per_port_rx_offload = {
 	.help_str = "port config <port_id> rx_offload vlan_strip|ipv4_cksum|"
 		    "udp_cksum|tcp_cksum|tcp_lro|qinq_strip|outer_ipv4_cksum|"
 		    "macsec_strip|header_split|vlan_filter|vlan_extend|"
-		    "jumbo_frame|scatter|timestamp|security|keep_crc "
+		    "jumbo_frame|scatter|timestamp|security|keep_crc|rss_hash "
 		    "on|off",
 	.tokens = {
 		(void *)&cmd_config_per_port_rx_offload_result_port,

doc/guides/nics/features.rst

@@ -274,6 +274,7 @@ Supports RSS hashing on RX.
 
 * **[uses]     user config**: ``dev_conf.rxmode.mq_mode`` = ``ETH_MQ_RX_RSS_FLAG``.
 * **[uses]     user config**: ``dev_conf.rx_adv_conf.rss_conf``.
+* **[uses]     rte_eth_rxconf,rte_eth_rxmode**: ``offloads:DEV_RX_OFFLOAD_RSS_HASH``.
 * **[provides] rte_eth_dev_info**: ``flow_type_rss_offloads``.
 * **[provides] mbuf**: ``mbuf.ol_flags:PKT_RX_RSS_HASH``, ``mbuf.rss``.
 
@@ -286,6 +287,7 @@ Inner RSS
 Supports RX RSS hashing on Inner headers.
 
 * **[uses]    rte_flow_action_rss**: ``level``.
+* **[uses]    rte_eth_rxconf,rte_eth_rxmode**: ``offloads:DEV_RX_OFFLOAD_RSS_HASH``.
 * **[provides] mbuf**: ``mbuf.ol_flags:PKT_RX_RSS_HASH``, ``mbuf.rss``.
 
 

doc/guides/rel_notes/release_19_11.rst

@@ -101,6 +101,13 @@ New Features
   * This scheme will allow PMDs to avoid lookup to internal ptype table on Rx
     and thereby improve Rx performance if application wishes do so.
 
+* **Added Rx offload flag to enable or disable RSS update**
+
+  * Added new Rx offload flag `DEV_RX_OFFLOAD_RSS_HASH` which can be used to
+    enable/disable PMDs write to `rte_mbuf::hash::rss`.
+  * PMDs notify the validity of `rte_mbuf::hash:rss` to the application
+    by enabling `PKT_RX_RSS_HASH ` flag in `rte_mbuf::ol_flags`.
+
 * **Updated the enic driver.**
 
   * Added support for Geneve with options offload.

doc/guides/testpmd_app_ug/testpmd_funcs.rst

@@ -1680,7 +1680,7 @@ Enable or disable a per port Rx offloading on all Rx queues of a port::
                   vlan_strip, ipv4_cksum, udp_cksum, tcp_cksum, tcp_lro,
                   qinq_strip, outer_ipv4_cksum, macsec_strip,
                   header_split, vlan_filter, vlan_extend, jumbo_frame,
-                  scatter, timestamp, security, keep_crc
+                  scatter, timestamp, security, keep_crc, rss_hash
 
 This command should be run when the port is stopped, or else it will fail.
 

lib/librte_ethdev/rte_ethdev.c

@@ -129,6 +129,7 @@ static const struct {
 	RTE_RX_OFFLOAD_BIT2STR(KEEP_CRC),
 	RTE_RX_OFFLOAD_BIT2STR(SCTP_CKSUM),
 	RTE_RX_OFFLOAD_BIT2STR(OUTER_UDP_CKSUM),
+	RTE_RX_OFFLOAD_BIT2STR(RSS_HASH),
 };
 
 #undef RTE_RX_OFFLOAD_BIT2STR
@@ -1305,6 +1306,17 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
 		goto rollback;
 	}
 
+	/* Check if Rx RSS distribution is disabled but RSS hash is enabled. */
+	if (((dev_conf->rxmode.mq_mode & ETH_MQ_RX_RSS_FLAG) == 0) &&
+	    (dev_conf->rxmode.offloads & DEV_RX_OFFLOAD_RSS_HASH)) {
+		RTE_ETHDEV_LOG(ERR,
+			"Ethdev port_id=%u config invalid Rx mq_mode without RSS but %s offload is requested",
+			port_id,
+			rte_eth_dev_rx_offload_name(DEV_RX_OFFLOAD_RSS_HASH));
+		ret = -EINVAL;
+		goto rollback;
+	}
+
 	/*
 	 * Setup new number of RX/TX queues and reconfigure device.
 	 */

lib/librte_ethdev/rte_ethdev.h

@@ -1088,6 +1088,7 @@ struct rte_eth_conf {
 #define DEV_RX_OFFLOAD_KEEP_CRC		0x00010000
 #define DEV_RX_OFFLOAD_SCTP_CKSUM	0x00020000
 #define DEV_RX_OFFLOAD_OUTER_UDP_CKSUM  0x00040000
+#define DEV_RX_OFFLOAD_RSS_HASH		0x00080000
 
 #define DEV_RX_OFFLOAD_CHECKSUM (DEV_RX_OFFLOAD_IPV4_CKSUM | \
 				 DEV_RX_OFFLOAD_UDP_CKSUM | \