Merge branch 'sfc-udp-rss'

Edward Cree says:

====================
sfc: enable 4-tuple UDP RSS hashing

EF10 based NICs have configurable RSS hash fields, and can be made to take the
ports into the hash on UDP (they already do so for TCP).  This patch series
enables this, in order to improve spreading of UDP traffic.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/ef10.c

@@ -2245,6 +2245,86 @@ static void efx_ef10_tx_write(struct efx_tx_queue *tx_queue)
 	}
 }
 
+#define RSS_MODE_HASH_ADDRS	(1 << RSS_MODE_HASH_SRC_ADDR_LBN |\
+				 1 << RSS_MODE_HASH_DST_ADDR_LBN)
+#define RSS_MODE_HASH_PORTS	(1 << RSS_MODE_HASH_SRC_PORT_LBN |\
+				 1 << RSS_MODE_HASH_DST_PORT_LBN)
+#define RSS_CONTEXT_FLAGS_DEFAULT	(1 << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_TOEPLITZ_IPV4_EN_LBN |\
+					 1 << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_TOEPLITZ_TCPV4_EN_LBN |\
+					 1 << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_TOEPLITZ_IPV6_EN_LBN |\
+					 1 << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_TOEPLITZ_TCPV6_EN_LBN |\
+					 (RSS_MODE_HASH_ADDRS | RSS_MODE_HASH_PORTS) << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_TCP_IPV4_RSS_MODE_LBN |\
+					 RSS_MODE_HASH_ADDRS << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_UDP_IPV4_RSS_MODE_LBN |\
+					 RSS_MODE_HASH_ADDRS << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_OTHER_IPV4_RSS_MODE_LBN |\
+					 (RSS_MODE_HASH_ADDRS | RSS_MODE_HASH_PORTS) << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_TCP_IPV6_RSS_MODE_LBN |\
+					 RSS_MODE_HASH_ADDRS << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_UDP_IPV6_RSS_MODE_LBN |\
+					 RSS_MODE_HASH_ADDRS << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_OTHER_IPV6_RSS_MODE_LBN)
+
+static int efx_ef10_get_rss_flags(struct efx_nic *efx, u32 context, u32 *flags)
+{
+	/* Firmware had a bug (sfc bug 61952) where it would not actually
+	 * fill in the flags field in the response to MC_CMD_RSS_CONTEXT_GET_FLAGS.
+	 * This meant that it would always contain whatever was previously
+	 * in the MCDI buffer.  Fortunately, all firmware versions with
+	 * this bug have the same default flags value for a newly-allocated
+	 * RSS context, and the only time we want to get the flags is just
+	 * after allocating.  Moreover, the response has a 32-bit hole
+	 * where the context ID would be in the request, so we can use an
+	 * overlength buffer in the request and pre-fill the flags field
+	 * with what we believe the default to be.  Thus if the firmware
+	 * has the bug, it will leave our pre-filled value in the flags
+	 * field of the response, and we will get the right answer.
+	 *
+	 * However, this does mean that this function should NOT be used if
+	 * the RSS context flags might not be their defaults - it is ONLY
+	 * reliably correct for a newly-allocated RSS context.
+	 */
+	MCDI_DECLARE_BUF(inbuf, MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_LEN);
+	MCDI_DECLARE_BUF(outbuf, MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_LEN);
+	size_t outlen;
+	int rc;
+
+	/* Check we have a hole for the context ID */
+	BUILD_BUG_ON(MC_CMD_RSS_CONTEXT_GET_FLAGS_IN_LEN != MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_FLAGS_OFST);
+	MCDI_SET_DWORD(inbuf, RSS_CONTEXT_GET_FLAGS_IN_RSS_CONTEXT_ID, context);
+	MCDI_SET_DWORD(inbuf, RSS_CONTEXT_GET_FLAGS_OUT_FLAGS,
+		       RSS_CONTEXT_FLAGS_DEFAULT);
+	rc = efx_mcdi_rpc(efx, MC_CMD_RSS_CONTEXT_GET_FLAGS, inbuf,
+			  sizeof(inbuf), outbuf, sizeof(outbuf), &outlen);
+	if (rc == 0) {
+		if (outlen < MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_LEN)
+			rc = -EIO;
+		else
+			*flags = MCDI_DWORD(outbuf, RSS_CONTEXT_GET_FLAGS_OUT_FLAGS);
+	}
+	return rc;
+}
+
+/* Attempt to enable 4-tuple UDP hashing on the specified RSS context.
+ * If we fail, we just leave the RSS context at its default hash settings,
+ * which is safe but may slightly reduce performance.
+ * Defaults are 4-tuple for TCP and 2-tuple for UDP and other-IP, so we
+ * just need to set the UDP ports flags (for both IP versions).
+ */
+static void efx_ef10_set_rss_flags(struct efx_nic *efx, u32 context)
+{
+	MCDI_DECLARE_BUF(inbuf, MC_CMD_RSS_CONTEXT_SET_FLAGS_IN_LEN);
+	u32 flags;
+
+	BUILD_BUG_ON(MC_CMD_RSS_CONTEXT_SET_FLAGS_OUT_LEN != 0);
+
+	if (efx_ef10_get_rss_flags(efx, context, &flags) != 0)
+		return;
+	MCDI_SET_DWORD(inbuf, RSS_CONTEXT_SET_FLAGS_IN_RSS_CONTEXT_ID, context);
+	flags |= RSS_MODE_HASH_PORTS << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_UDP_IPV4_RSS_MODE_LBN;
+	flags |= RSS_MODE_HASH_PORTS << MC_CMD_RSS_CONTEXT_GET_FLAGS_OUT_UDP_IPV6_RSS_MODE_LBN;
+	MCDI_SET_DWORD(inbuf, RSS_CONTEXT_SET_FLAGS_IN_FLAGS, flags);
+	if (!efx_mcdi_rpc(efx, MC_CMD_RSS_CONTEXT_SET_FLAGS, inbuf, sizeof(inbuf),
+			  NULL, 0, NULL))
+		/* Succeeded, so UDP 4-tuple is now enabled */
+		efx->rx_hash_udp_4tuple = true;
+}
+
 static int efx_ef10_alloc_rss_context(struct efx_nic *efx, u32 *context,
 				      bool exclusive, unsigned *context_size)
 {
@@ -2290,6 +2370,10 @@ static int efx_ef10_alloc_rss_context(struct efx_nic *efx, u32 *context,
 	if (context_size)
 		*context_size = rss_spread;
 
+	if (nic_data->datapath_caps &
+	    1 << MC_CMD_GET_CAPABILITIES_OUT_ADDITIONAL_RSS_MODES_LBN)
+		efx_ef10_set_rss_flags(efx, *context);
+
 	return 0;
 }
 

drivers/net/ethernet/sfc/ethtool.c

@@ -968,20 +968,24 @@ efx_ethtool_get_rxnfc(struct net_device *net_dev,
 
 		info->data = 0;
 		switch (info->flow_type) {
+		case UDP_V4_FLOW:
+			if (efx->rx_hash_udp_4tuple)
+				/* fall through */
 		case TCP_V4_FLOW:
-			info->data |= RXH_L4_B_0_1 | RXH_L4_B_2_3;
+				info->data |= RXH_L4_B_0_1 | RXH_L4_B_2_3;
 			/* fall through */
-		case UDP_V4_FLOW:
 		case SCTP_V4_FLOW:
 		case AH_ESP_V4_FLOW:
 		case IPV4_FLOW:
 			info->data |= RXH_IP_SRC | RXH_IP_DST;
 			min_revision = EFX_REV_FALCON_B0;
 			break;
+		case UDP_V6_FLOW:
+			if (efx->rx_hash_udp_4tuple)
+				/* fall through */
 		case TCP_V6_FLOW:
-			info->data |= RXH_L4_B_0_1 | RXH_L4_B_2_3;
+				info->data |= RXH_L4_B_0_1 | RXH_L4_B_2_3;
 			/* fall through */
-		case UDP_V6_FLOW:
 		case SCTP_V6_FLOW:
 		case AH_ESP_V6_FLOW:
 		case IPV6_FLOW:

drivers/net/ethernet/sfc/net_driver.h

@@ -853,6 +853,7 @@ struct vfdi_status;
  * @rx_hash_key: Toeplitz hash key for RSS
  * @rx_indir_table: Indirection table for RSS
  * @rx_scatter: Scatter mode enabled for receives
+ * @rx_hash_udp_4tuple: UDP 4-tuple hashing enabled
  * @int_error_count: Number of internal errors seen recently
  * @int_error_expire: Time at which error count will be expired
  * @irq_soft_enabled: Are IRQs soft-enabled? If not, IRQ handler will
@@ -990,6 +991,7 @@ struct efx_nic {
 	u8 rx_hash_key[40];
 	u32 rx_indir_table[128];
 	bool rx_scatter;
+	bool rx_hash_udp_4tuple;
 
 	unsigned int_error_count;
 	unsigned long int_error_expire;