RDMA/mlx5: Use UMEM attribute for QP doorbell record

Add an optional mlx5 driver-namespace UMEM attribute on QP
create so userspace can supply the doorbell record umem
explicitly, symmetric to the CQ side. Resolve it inside
mlx5_ib_db_map_user() and use it as a private DBR page when
present; otherwise take the existing UHW share-or-pin path
that preserves per-page DBR sharing across CQ/QP/SRQ in the
same process.

Add mlx5's first UVERBS_OBJECT_QP UAPI definition chain to
attach the new attr.

Link: https://patch.msgid.link/r/20260529134312.2836341-17-jiri@resnulli.us
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 419489bd2199666ec08518c83510d752bd40dc5b..12bfefc91b023c640cfb569da2be820322536498 100644 (file)
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -4456,6 +4456,7 @@ static const struct uapi_definition mlx5_ib_defs[] = {
        UAPI_DEF_CHAIN(mlx5_ib_std_types_defs),
        UAPI_DEF_CHAIN(mlx5_ib_dm_defs),
        UAPI_DEF_CHAIN(mlx5_ib_create_cq_defs),
+       UAPI_DEF_CHAIN(mlx5_ib_create_qp_defs),
 
        UAPI_DEF_CHAIN_OBJ_TREE(UVERBS_OBJECT_DEVICE, &mlx5_ib_query_context),
        UAPI_DEF_CHAIN_OBJ_TREE(UVERBS_OBJECT_MR, &mlx5_ib_reg_dmabuf_mr),

diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 078f281bcdac920e0363cb7c907e24b3df2c94dc..1f03c05b0cbdc994fcc8bbc8b08e9a06cd7a7d68 100644 (file)
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -1511,6 +1511,7 @@ extern const struct uapi_definition mlx5_ib_flow_defs[];
 extern const struct uapi_definition mlx5_ib_qos_defs[];
 extern const struct uapi_definition mlx5_ib_std_types_defs[];
 extern const struct uapi_definition mlx5_ib_create_cq_defs[];
+extern const struct uapi_definition mlx5_ib_create_qp_defs[];
 
 static inline int is_qp1(enum ib_qp_type qp_type)
 {

diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 58997714df700ae0f73ab579f02e509f4cd1d432..e8d34d54b43527e0595ec9e2fb93dc7e9bedba92 100644 (file)
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -44,6 +44,9 @@
 #include "qp.h"
 #include "wr.h"
 
+#define UVERBS_MODULE_NAME mlx5_ib
+#include <rdma/uverbs_named_ioctl.h>
+
 enum {
        MLX5_IB_ACK_REQ_FREQ    = 8,
 };
@@ -1053,7 +1056,9 @@ static int _create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
                resp->bfreg_index = MLX5_IB_INVALID_BFREG;
        qp->bfregn = bfregn;
 
-       err = mlx5_ib_db_map_user(context, NULL, 0, ucmd->db_addr, &qp->db);
+       err = mlx5_ib_db_map_user(context, attrs,
+                                 MLX5_IB_ATTR_CREATE_QP_DBR_BUF_UMEM,
+                                 ucmd->db_addr, &qp->db);
        if (err) {
                mlx5_ib_dbg(dev, "map failed\n");
                goto err_free;
@@ -5877,3 +5882,15 @@ void mlx5_ib_qp_event_cleanup(void)
 {
        destroy_workqueue(mlx5_ib_qp_event_wq);
 }
+
+ADD_UVERBS_ATTRIBUTES_SIMPLE(
+       mlx5_ib_qp_create,
+       UVERBS_OBJECT_QP,
+       UVERBS_METHOD_QP_CREATE,
+       UVERBS_ATTR_UMEM(MLX5_IB_ATTR_CREATE_QP_DBR_BUF_UMEM,
+                        UA_OPTIONAL));
+
+const struct uapi_definition mlx5_ib_create_qp_defs[] = {
+       UAPI_DEF_CHAIN_OBJ_TREE(UVERBS_OBJECT_QP, &mlx5_ib_qp_create),
+       {},
+};

diff --git a/include/uapi/rdma/mlx5_user_ioctl_cmds.h b/include/uapi/rdma/mlx5_user_ioctl_cmds.h
index b63e75034cda2f8b32845e9980c5bfbfc4eb5d1a..ddb898afd813450849836a532a515668edbf2cb0 100644 (file)
--- a/include/uapi/rdma/mlx5_user_ioctl_cmds.h
+++ b/include/uapi/rdma/mlx5_user_ioctl_cmds.h
@@ -277,6 +277,10 @@ enum mlx5_ib_create_cq_attrs {
        MLX5_IB_ATTR_CREATE_CQ_DBR_BUF_UMEM,
 };
 
+enum mlx5_ib_create_qp_attrs {
+       MLX5_IB_ATTR_CREATE_QP_DBR_BUF_UMEM = UVERBS_ID_DRIVER_NS_WITH_UHW,
+};
+
 enum mlx5_ib_reg_dmabuf_mr_attrs {
        MLX5_IB_ATTR_REG_DMABUF_MR_ACCESS_FLAGS = (1U << UVERBS_ID_NS_SHIFT),
 };