sfc: enable 4-tuple RSS hashing for UDP

This improves UDP spreading, and also slightly improves GRO performance
of encapsulated TCP on 7000 series NICs.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index 00279da6a1e8b4adfd40df76da7d41da325ea6d2..9f6d7690bc0a2c3d66d5c93b6313d40d38061e81 100644 (file)
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -2245,6 +2245,84 @@ 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);
+       efx_mcdi_rpc(efx, MC_CMD_RSS_CONTEXT_SET_FLAGS, inbuf, sizeof(inbuf),
+                    NULL, 0, NULL);
+}
+
 static int efx_ef10_alloc_rss_context(struct efx_nic *efx, u32 *context,
                                      bool exclusive, unsigned *context_size)
 {
@@ -2290,6 +2368,10 @@ 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;
 }