mlx5dv_devx_obj_cmlx5dv/devxtobj_createf/ destroy//gmodify(/query / general(3)
NAME
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 inter-
face
SYNOPSIS
#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);
DESCRIPTION
Create / destroy / modify / query a devx object, issue a general com-
mand 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 com-
mand 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 com-
mands 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 in-
cludes 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.
ARGUMENTS
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 asyn-
chronous mode.
RETURN VALUE
Upon success mlx5dv_devx_create_obj will return a new struct mlx5dv_de-
vx_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.
SEE ALSO
mlx5dv_open_device, mlx5dv_devx_create_cmd_comp, mlx5dv_de-
vx_get_async_cmd_comp
#AUTHOR
Yishai Hadas <yishaih@mellanox.com>
mlx5dv_devx_obj_create / destroy / modify /query / general(3)
Generated by dwww version 1.15 on Wed Jun 26 18:09:20 CEST 2024.