net/mlx5e: Support ETH_RSS_HASH_XOR

The ConnectX-4 HW implements inverted XOR8.
To make it act as XOR we re-order the HW RSS indirection table.

Set XOR to be the default RSS hash function and add ethtool API to
control it.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 3d23bd6..61d8433 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -195,6 +195,7 @@ struct mlx5e_params {
        u16 rx_hash_log_tbl_sz;
        bool lro_en;
        u32 lro_wqe_sz;
+       u8  rss_hfunc;
 };
 
 enum {

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
index 3889384..cb28535 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -662,6 +662,43 @@ out:
        return err;
 }
 
+static int mlx5e_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key,
+                         u8 *hfunc)
+{
+       struct mlx5e_priv *priv = netdev_priv(netdev);
+
+       if (hfunc)
+               *hfunc = priv->params.rss_hfunc;
+
+       return 0;
+}
+
+static int mlx5e_set_rxfh(struct net_device *netdev, const u32 *indir,
+                         const u8 *key, const u8 hfunc)
+{
+       struct mlx5e_priv *priv = netdev_priv(netdev);
+       int err = 0;
+
+       if (hfunc == ETH_RSS_HASH_NO_CHANGE)
+               return 0;
+
+       if ((hfunc != ETH_RSS_HASH_XOR) &&
+           (hfunc != ETH_RSS_HASH_TOP))
+               return -EINVAL;
+
+       mutex_lock(&priv->state_lock);
+
+       priv->params.rss_hfunc = hfunc;
+       if (test_bit(MLX5E_STATE_OPENED, &priv->state)) {
+               mlx5e_close_locked(priv->netdev);
+               err = mlx5e_open_locked(priv->netdev);
+       }
+
+       mutex_unlock(&priv->state_lock);
+
+       return err;
+}
+
 const struct ethtool_ops mlx5e_ethtool_ops = {
        .get_drvinfo       = mlx5e_get_drvinfo,
        .get_link          = ethtool_op_get_link,
@@ -676,4 +713,6 @@ const struct ethtool_ops mlx5e_ethtool_ops = {
        .set_coalesce      = mlx5e_set_coalesce,
        .get_settings      = mlx5e_get_settings,
        .set_settings      = mlx5e_set_settings,
+       .get_rxfh          = mlx5e_get_rxfh,
+       .set_rxfh          = mlx5e_set_rxfh,
 };

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 40206da..07d3627 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -1158,6 +1158,24 @@ static void mlx5e_close_tises(struct mlx5e_priv *priv)
                mlx5e_close_tis(priv, tc);
 }
 
+static int mlx5e_rx_hash_fn(int hfunc)
+{
+       return (hfunc == ETH_RSS_HASH_TOP) ?
+              MLX5_RX_HASH_FN_TOEPLITZ :
+              MLX5_RX_HASH_FN_INVERTED_XOR8;
+}
+
+static int mlx5e_bits_invert(unsigned long a, int size)
+{
+       int inv = 0;
+       int i;
+
+       for (i = 0; i < size; i++)
+               inv |= (test_bit(size - i - 1, &a) ? 1 : 0) << i;
+
+       return inv;
+}
+
 static int mlx5e_open_rqt(struct mlx5e_priv *priv)
 {
        struct mlx5_core_dev *mdev = priv->mdev;
@@ -1166,11 +1184,10 @@ static int mlx5e_open_rqt(struct mlx5e_priv *priv)
        void *rqtc;
        int inlen;
        int err;
-       int sz;
+       int log_tbl_sz = priv->params.rx_hash_log_tbl_sz;
+       int sz = 1 << log_tbl_sz;
        int i;
 
-       sz = 1 << priv->params.rx_hash_log_tbl_sz;
-
        inlen = MLX5_ST_SZ_BYTES(create_rqt_in) + sizeof(u32) * sz;
        in = mlx5_vzalloc(inlen);
        if (!in)
@@ -1182,8 +1199,12 @@ static int mlx5e_open_rqt(struct mlx5e_priv *priv)
        MLX5_SET(rqtc, rqtc, rqt_max_size, sz);
 
        for (i = 0; i < sz; i++) {
-               int ix = i % priv->params.num_channels;
+               int ix = i;
+
+               if (priv->params.rss_hfunc == ETH_RSS_HASH_XOR)
+                       ix = mlx5e_bits_invert(i, log_tbl_sz);
 
+               ix = ix % priv->params.num_channels;
                MLX5_SET(rqtc, rqtc, rq_num[i], priv->channel[ix]->rq.rqn);
        }
 
@@ -1254,12 +1275,16 @@ static void mlx5e_build_tir_ctx(struct mlx5e_priv *priv, u32 *tirc, int tt)
                MLX5_SET(tirc, tirc, indirect_table,
                         priv->rqtn);
                MLX5_SET(tirc, tirc, rx_hash_fn,
-                        MLX5_TIRC_RX_HASH_FN_HASH_TOEPLITZ);
-               MLX5_SET(tirc, tirc, rx_hash_symmetric, 1);
-               netdev_rss_key_fill(MLX5_ADDR_OF(tirc, tirc,
-                                                rx_hash_toeplitz_key),
-                                   MLX5_FLD_SZ_BYTES(tirc,
-                                                     rx_hash_toeplitz_key));
+                        mlx5e_rx_hash_fn(priv->params.rss_hfunc));
+               if (priv->params.rss_hfunc == ETH_RSS_HASH_TOP) {
+                       void *rss_key = MLX5_ADDR_OF(tirc, tirc,
+                                                    rx_hash_toeplitz_key);
+                       size_t len = MLX5_FLD_SZ_BYTES(tirc,
+                                                      rx_hash_toeplitz_key);
+
+                       MLX5_SET(tirc, tirc, rx_hash_symmetric, 1);
+                       netdev_rss_key_fill(rss_key, len);
+               }
                break;
        }
 
@@ -1700,6 +1725,7 @@ static void mlx5e_build_netdev_priv(struct mlx5_core_dev *mdev,
                MLX5E_PARAMS_DEFAULT_RX_HASH_LOG_TBL_SZ;
        priv->params.num_tc                = 1;
        priv->params.default_vlan_prio     = 0;
+       priv->params.rss_hfunc             = ETH_RSS_HASH_XOR;
 
        priv->params.lro_en = false && !!MLX5_CAP_ETH(priv->mdev, lro_cap);
        priv->params.lro_wqe_sz            =

diff --git a/include/linux/mlx5/mlx5_ifc.h b/include/linux/mlx5/mlx5_ifc.h
index 6d2f6fe..c60a62b 100644 (file)
--- a/include/linux/mlx5/mlx5_ifc.h
+++ b/include/linux/mlx5/mlx5_ifc.h
@@ -1936,9 +1936,9 @@ enum {
 };
 
 enum {
-       MLX5_TIRC_RX_HASH_FN_HASH_NONE           = 0x0,
-       MLX5_TIRC_RX_HASH_FN_HASH_INVERTED_XOR8  = 0x1,
-       MLX5_TIRC_RX_HASH_FN_HASH_TOEPLITZ       = 0x2,
+       MLX5_RX_HASH_FN_NONE           = 0x0,
+       MLX5_RX_HASH_FN_INVERTED_XOR8  = 0x1,
+       MLX5_RX_HASH_FN_TOEPLITZ       = 0x2,
 };
 
 enum {