---
name: "mlx5dv_reg_dmabuf_mr"
section: "3"
platform: "linux"
package: "rdma-core"
version: "65.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/mlx5dv_reg_dmabuf_mr"
---

# mlx5dv\_reg\_dmabuf\_mr(3)

Register a dma-buf based memory region (MR)

## NAME

mlx5dv\_reg\_dmabuf\_mr - Register a dma-buf based memory region (MR)

## SYNOPSIS

-

  ```
  #include <infiniband/mlx5dv.h>
  struct ibv_mr *mlx5dv_reg_dmabuf_mr(struct ibv_pd *pd, uint64_t offset,
                                      size_t length, uint64_t iova, int fd,
                                      int access, int mlx5_access)
  ```

## DESCRIPTION

Register a dma-buf based memory region (MR), it follows the functionality of *ibv\_reg\_dmabuf\_mr()* with the ability to supply specific mlx5 access flags.

## ARGUMENTS

- *pd*

  The associated protection domain.

- *offset*

  The offset of the dma-buf where the MR starts.

- *length*

  -

  ```
    The length of the MR.
  ```

- *iova*

  Specifies the virtual base address of the MR when accessed through a lkey or rkey. It must have the same page offset as *offset* and be aligned with the system page size.

- *fd*

  The file descriptor that the dma-buf is identified by.

- *access*

  The desired memory protection attributes; it is either 0 or the bitwise OR of one or more of *enum ibv\_access\_flags*.

- *mlx5\_access*

  A specific device access flags, it is either 0 or the below.

  *MLX5DV\_REG\_DMABUF\_ACCESS\_DATA\_DIRECT* if set, this MR will be accessed through the Data Direct engine bonded with that RDMA device.

## RETURN VALUE

Upon success returns a pointer to the registered MR, or NULL if the request fails, in that case the value of errno indicates the failure reason.

## SEE ALSO

*ibv\_reg\_dmabuf\_mr(3)*, *[mlx5dv\_get\_data\_direct\_sysfs\_path(3)](/mlx5dv_get_data_direct_sysfs_path/3.md)*

## AUTHOR

Yishai Hadas ⟨yishaih@nvidia.com⟩\\c