IB/mlx5: Add support for RSS on the inner packet

Some user space application would like to do RSS on the inner
packet fields instead on the outer.
When MLX5_RX_HASH_INNER is set with one or more of the other
hash fields, then the RSS will be done using the inner packet.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mlx5/qp.c

@@ -1403,6 +1403,12 @@ static int create_rss_raw_qp_tir(struct mlx5_ib_dev *dev, struct mlx5_ib_qp *qp,
 		return -EOPNOTSUPP;
 	}
 
+	if (ucmd.rx_hash_fields_mask & MLX5_RX_HASH_INNER &&
+	    !(ucmd.flags & MLX5_QP_FLAG_TUNNEL_OFFLOADS)) {
+		mlx5_ib_dbg(dev, "Tunnel offloads must be set for inner RSS\n");
+		return -EOPNOTSUPP;
+	}
+
 	err = ib_copy_to_udata(udata, &resp, min_resp_len);
 	if (err) {
 		mlx5_ib_dbg(dev, "copy failed\n");
@@ -1426,6 +1432,11 @@ static int create_rss_raw_qp_tir(struct mlx5_ib_dev *dev, struct mlx5_ib_qp *qp,
 	if (ucmd.flags & MLX5_QP_FLAG_TUNNEL_OFFLOADS)
 		MLX5_SET(tirc, tirc, tunneled_offload_en, 1);
 
+	if (ucmd.rx_hash_fields_mask & MLX5_RX_HASH_INNER)
+		hfso = MLX5_ADDR_OF(tirc, tirc, rx_hash_field_selector_inner);
+	else
+		hfso = MLX5_ADDR_OF(tirc, tirc, rx_hash_field_selector_outer);
+
 	switch (ucmd.rx_hash_function) {
 	case MLX5_RX_HASH_FUNC_TOEPLITZ:
 	{

include/uapi/rdma/mlx5-abi.h

@@ -303,7 +303,9 @@ enum mlx5_rx_hash_fields {
 	MLX5_RX_HASH_SRC_PORT_TCP	= 1 << 4,
 	MLX5_RX_HASH_DST_PORT_TCP	= 1 << 5,
 	MLX5_RX_HASH_SRC_PORT_UDP	= 1 << 6,
-	MLX5_RX_HASH_DST_PORT_UDP	= 1 << 7
+	MLX5_RX_HASH_DST_PORT_UDP	= 1 << 7,
+	/* Save bits for future fields */
+	MLX5_RX_HASH_INNER		= 1 << 31
 };
 
 struct mlx5_ib_create_qp_rss {