RDMA/mlx5: Don't compare mkey tags in DEVX indirect mkey

According to the ib spec:
If the CI supports the Base Memory Management Extensions defined in this
specification, the L_Key format must consist of:
24 bit index in the most significant bits of the R_Key, and
8 bit key in the least significant bits of the R_Key
Through a successful Allocate L_Key verb invocation, the CI must let the
consumer own the key portion of the returned R_Key

Therefore, when creating a mkey using DEVX, the consumer is allowed to
change the key part. The kernel should compare only the index part of a
R_Key to determine equality with another R_Key.

Adding capability in order not to break backward compatibility.

Fixes: 534fd7aa ("IB/mlx5: Manage indirection mkey upon DEVX flow for ODP")
Link: https://lore.kernel.org/r/3d669aacea85a3a15c3b3b953b3eaba3f80ef9be.1659255945.git.leonro@nvidia.comSigned-off-by: Aharon Landau <aharonl@nvidia.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/mlx5/main.c

@@ -1826,6 +1826,9 @@ static int set_ucontext_resp(struct ib_ucontext *uctx,
 	if (MLX5_CAP_GEN(dev->mdev, drain_sigerr))
 		resp->comp_mask |= MLX5_IB_ALLOC_UCONTEXT_RESP_MASK_SQD2RTS;
 
+	resp->comp_mask |=
+		MLX5_IB_ALLOC_UCONTEXT_RESP_MASK_MKEY_UPDATE_TAG;
+
 	return 0;
 }
 

drivers/infiniband/hw/mlx5/odp.c

@@ -795,7 +795,8 @@ static bool mkey_is_eq(struct mlx5_ib_mkey *mmkey, u32 key)
 {
 	if (!mmkey)
 		return false;
-	if (mmkey->type == MLX5_MKEY_MW)
+	if (mmkey->type == MLX5_MKEY_MW ||
+	    mmkey->type == MLX5_MKEY_INDIRECT_DEVX)
 		return mlx5_base_mkey(mmkey->key) == mlx5_base_mkey(key);
 	return mmkey->key == key;
 }

include/uapi/rdma/mlx5-abi.h

@@ -104,6 +104,7 @@ enum mlx5_ib_alloc_ucontext_resp_mask {
 	MLX5_IB_ALLOC_UCONTEXT_RESP_MASK_ECE               = 1UL << 2,
 	MLX5_IB_ALLOC_UCONTEXT_RESP_MASK_SQD2RTS           = 1UL << 3,
 	MLX5_IB_ALLOC_UCONTEXT_RESP_MASK_REAL_TIME_TS	   = 1UL << 4,
+	MLX5_IB_ALLOC_UCONTEXT_RESP_MASK_MKEY_UPDATE_TAG   = 1UL << 5,
 };
 
 enum mlx5_user_cmds_supp_uhw {