RDMA/mlx5: Introduce UAPI to query PD attributes

Introduce UAPI to query PD attributes, this can be used to retrieve PD
attributes by having the PD handle of the created one and owning the
command FD for the ucontxet.

Link: https://lore.kernel.org/r/20200630093916.332097-7-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

include/uapi/rdma/mlx5_user_ioctl_cmds.h

@@ -290,4 +290,14 @@ enum mlx5_ib_create_flow_action_create_packet_reformat_attrs {
 	MLX5_IB_ATTR_CREATE_PACKET_REFORMAT_DATA_BUF,
 };
 
+enum mlx5_ib_query_pd_attrs {
+	MLX5_IB_ATTR_QUERY_PD_HANDLE = (1U << UVERBS_ID_NS_SHIFT),
+	MLX5_IB_ATTR_QUERY_PD_RESP_PDN,
+};
+
+enum mlx5_ib_pd_methods {
+	MLX5_IB_METHOD_PD_QUERY = (1U << UVERBS_ID_NS_SHIFT),
+
+};
+
 #endif