|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
NAME | SYNOPSIS | DESCRIPTION | ARGUMENTS | RETURN VALUE | SEE ALSO | COLOPHON |
|
|
|
mlx5dv_devx_obj...query / general(3) mlx5dv_devx_obj...query / general(3)
mlx5dv_devx_obj_create - Creates a devx object
mlx5dv_devx_obj_destroy - Destroys a devx object
mlx5dv_devx_obj_modify - Modifies a devx object
mlx5dv_devx_obj_query - Queries a devx object
mlx5dv_devx_obj_query_async - Queries a devx object in an
asynchronous mode
mlx5dv_devx_general_cmd - Issues a general command over the devx
interface
#include <infiniband/mlx5dv.h>
struct mlx5dv_devx_obj *
mlx5dv_devx_obj_create(struct ibv_context *context, const void *in, size_t inlen,
void *out, size_t outlen);
int mlx5dv_devx_obj_query(struct mlx5dv_devx_obj *obj, const void *in, size_t inlen,
void *out, size_t outlen);
int mlx5dv_devx_obj_query_async(struct mlx5dv_devx_obj *obj, const void *in,
size_t inlen, size_t outlen,
uint64_t wr_id,
struct mlx5dv_devx_cmd_comp *cmd_comp);
int mlx5dv_devx_obj_modify(struct mlx5dv_devx_obj *obj, const void *in, size_t inlen,
void *out, size_t outlen);
int mlx5dv_devx_obj_destroy(struct mlx5dv_devx_obj *obj);
int mlx5dv_devx_general_cmd(struct ibv_context *context, const void *in, size_t inlen,
void *out, size_t outlen);
Create / destroy / modify / query a devx object, issue a general
command over the devx interface.
The DEVX API enables direct access from the user space area to the
mlx5 device driver by using the KABI mechanism. The main purpose
is to make the user space driver as independent as possible from
the kernel so that future device functionality and commands can be
activated with minimal to none kernel changes.
A DEVX object represents some underlay firmware object, the input
command to create it is some raw data given by the user
application which should match the device specification. Upon
successful creation the output buffer includes the raw data from
the device according to its specification, this data can be used
as part of related firmware commands to this object.
Once the DEVX object is created it can be
queried/modified/destroyed by the matching mlx5dv_devx_obj_xxx()
API. Both the input and the output for those APIs need to match
the device specification as well.
The mlx5dv_devx_general_cmd() API enables issuing some general
command which is not related to an object such as query device
capabilities.
The mlx5dv_devx_obj_query_async() API is similar to the query
object API, however, it runs asynchronously without blocking. The
input includes an mlx5dv_devx_cmd_comp object and an identifier
named `wr_id' for this command. The response should be read upon
success with the mlx5dv_devx_get_async_cmd_comp() API. The
`wr_id' that was supplied as an input is returned as part of the
response to let application knows for which command the response
is related to.
An application can gradually migrate to use DEVX according to its
needs, it is not all or nothing. For example it can create an
ibv_cq via ibv_create_cq() verb and then use the returned cqn to
create a DEVX QP object by the mlx5dv_devx_obj_create() API which
needs that cqn.
The above example can enable an application to create a QP with
some driver specific attributes that are not exposed in the
ibv_create_qp() API, in that case no user or kernel change may be
needed at all as the command input reaches directly to the
firmware.
The expected users for the DEVX APIs are application that use the
mlx5 DV APIs and are familiar with the device specification in
both control and data path.
To successfully create a DEVX object and work on, a DEVX context
must be created, this is done by the mlx5dv_open_device() API with
the MLX5DV_CONTEXT_FLAGS_DEVX flag.
context
RDMA device context to create the action on.
in A buffer which contains the command’s input data provided
in a device specification format.
inlen The size of in buffer in bytes.
out A buffer which contains the command’s output data according
to the device specification format.
outlen The size of out buffer in bytes.
obj For query, modify, destroy: the devx object to work on.
wr_id The command identifier when working in asynchronous mode.
cmd_comp
The command completion object to read the response from in
asynchronous mode.
Upon success mlx5dv_devx_create_obj will return a new struct
mlx5dv_devx_obj on error NULL will be returned and errno will be
set.
Upon success query, modify, destroy, general commands, 0 is
returned or the value of errno on a failure.
If the error value is EREMOTEIO, outbox.status and outbox.syndrome
will contain the command failure details.
mlx5dv_open_device, mlx5dv_devx_create_cmd_comp,
mlx5dv_devx_get_async_cmd_comp
#AUTHOR
Yishai Hadas ⟨yishaih@mellanox.com⟩
This page is part of the rdma-core (RDMA Core Userspace Libraries
and Daemons) project. Information about the project can be found
at ⟨https://github.com/linux-rdma/rdma-core⟩. If you have a bug
report for this manual page, send it to
linux-rdma@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨https://github.com/linux-rdma/rdma-core.git⟩ on 2025-08-11. (At
that time, the date of the most recent commit that was found in
the repository was 2025-08-04.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
mlx5dv_devx_obj...query / general(3)
|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|