mlx5dv_wr_mkey_configure(3) mlx5dv_wr_mkey_configure(3)
NAME
mlx5dv_wr_mkey_configure - Create a work request to configure an MKEY
mlx5dv_wr_set_mkey_access_flags - Set the memory protection attributes
for an MKEY
mlx5dv_wr_set_mkey_layout_list - Set a memory layout for an MKEY based
on SGE list
mlx5dv_wr_set_mkey_layout_interleaved - Set an interleaved memory lay-
out for an MKEY
SYNOPSIS
#include <infiniband/mlx5dv.h>
static inline void mlx5dv_wr_mkey_configure(struct mlx5dv_qp_ex *mqp,
struct mlx5dv_mkey *mkey,
uint8_t num_setters,
struct mlx5dv_mkey_conf_attr *attr);
static inline void mlx5dv_wr_set_mkey_access_flags(struct mlx5dv_qp_ex *mqp,
uint32_t access_flags);
static inline void mlx5dv_wr_set_mkey_layout_list(struct mlx5dv_qp_ex *mqp,
uint16_t num_sges,
const struct ibv_sge *sge);
static inline void mlx5dv_wr_set_mkey_layout_interleaved(struct mlx5dv_qp_ex *mqp,
uint32_t repeat_count,
uint16_t num_interleaved,
const struct mlx5dv_mr_interleaved *data);
DESCRIPTION
The MLX5DV MKEY configure API and the related setters
(mlx5dv_wr_set_mkey*) are an extension of IBV work request API
(ibv_wr*) with specific features for MLX5DV MKEY.
MKEYs allow creation of virtually-contiguous address spaces out of non-
contiguous chunks of memory regions already registered with the hard-
ware. Additionally it provides access to some advanced hardware off-
load features, e.g. signature offload.
These APIs are intended to be used to access additional functionality
beyond what is provided by mlx5dv_wr_mr_list() and mlx5dv_wr_mr_inter-
leaved(). The MKEY features can be optionally enabled using the mkey
configure setters. It allows using different features in the same
MKEY.
USAGE
To use these APIs a QP must be created using mlx5dv_create_qp(3) which
allows setting the MLX5DV_QP_EX_WITH_MKEY_CONFIGURE in send_ops_flags.
The MKEY configuration work request is created by calling
mlx5dv_wr_mkey_configure(), a WR builder function, followed by required
setter functions. num_setters is a number of required setters for the
WR. All setters are optional. num_setters can be zero to apply attr
only. Each setter can be called only once per the WR builder.
The WR configures mkey and applies attr of the builder function and
setter functions’ arguments for it. If mkey is already configured the
WR overrides some mkey properties depends on builder and setter func-
tions’ arguments (see details in setters’ description). To clear con-
figuration of mkey, use ibv_post_send() with IBV_WR_LOCAL_INV opcode or
ibv_wr_local_inv().
Current implementation requires the IBV_SEND_INLINE option to be set in
wr_flags field of ibv_qp_ex structure prior to builder function call.
Non-inline payload is currently not supported by this API. Please note
that inlining here is done for MKEY configuration data, not for user
data referenced by data layouts.
Once MKEY is configured, it may be used in subsequent work requests
(SEND, RDMA_READ, RDMA_WRITE, etc). If these work requests are posted
on the same QP, there is no need to wait for completion of MKEY config-
uration work request. They can be posted immediately after the last
setter (or builder if no setters). Usually there is no need to even
request a completion for MKEY configuration work request.
If completion is requested for MKEY configuration work request it will
be delivered with the IBV_WC_DRIVER1 opcode.
Builder function
mlx5dv_wr_mkey_configure()
Post a work request to configure an existing MKEY. With this
call alone it is possible to configure the MKEY and keep or re-
set signature attributes. This call may be followed by zero or
more optional setters.
mqp The QP to post the work request on.
mkey The MKEY to configure.
num_setters
The number of setters that must be called after this
function.
attr The MKEY configuration attributes
MKEY configuration attributes
MKEY configuration attributes are provided in mlx5dv_mkey_conf_attr
structure.
struct mlx5dv_mkey_conf_attr {
uint32_t conf_flags;
uint64_t comp_mask;
};
conf_flags
Bitwise OR of the following flags:
MLX5DV_MKEY_CONF_FLAG_RESET_SIG_ATTR
Reset the signature attributes of the MKEY. If not set,
previously configured signature attributes will be kept.
comp_mask
Reserved for future extension, must be 0 now.
Generic setters
mlx5dv_wr_set_mkey_access_flags()
Set the memory protection attributes for the MKEY. If the MKEY
is configured, the setter overrides the previous value. For ex-
ample, two MKEY configuration WRs are posted. The first one
sets IBV_ACCESS_REMOTE_READ. The second one sets IBV_ACCESS_RE-
MOTE_WRITE. In this case, the second WR overrides the memory
protection attributes, and only IBV_ACCESS_REMOTE_WRITE is al-
lowed for the MKEY when the WR is completed.
mqp The QP where an MKEY configuration work request was cre-
ated by mlx5dv_wr_mkey_configure().
access_flags
The desired memory protection attributes; it is either 0
or the bitwise OR of one or more of flags in enum ibv_ac-
cess_flags.
Data layout setters
Data layout setters define how data referenced by the MKEY will be
scattered/gathered in the memory. In order to use MKEY with RDMA oper-
ations it must be configured with a layout.
Not more than one data layout setter may follow builder function. Lay-
out can be updated in the next calls to builder function.
When MKEY is used in RDMA operations, it should be used in a zero-based
mode, i.e. the addr field in ibv_sge structure is an offset in the to-
tal data.
mlx5dv_wr_set_mkey_layout_list()
Set a memory layout for an MKEY based on SGE list. If the MKEY
is configured and the data layout was defined by some data lay-
out setter (not necessary this one), the setter overrides the
previous value.
Default WQE size can fit only 4 SGE entries. To allow more the
QP should be created with a larger WQE size that may fit it.
This should be done using the max_inline_data attribute of
struct ibv_qp_cap upon QP creation.
mqp The QP where an MKEY configuration work request was cre-
ated by mlx5dv_wr_mkey_configure().
num_sges
Number of SGEs in the list.
sge Pointer to the list of ibv_sge structures.
mlx5dv_wr_set_mkey_layout_interleaved()
Set an interleaved memory layout for an MKEY. If the MKEY is
configured and the data layout was defined by some data layout
setter (not necessary this one), the setter overrides the previ-
ous value.
Default WQE size can fit only 3 interleaved entries. To allow
more the QP should be created with a larger WQE size that may
fit it. This should be done using the max_inline_data attribute
of struct ibv_qp_cap upon QP creation.
As one entry will be consumed for strided header, the MKEY
should be created with one more entry than the required num_in-
terleaved.
mqp The QP where an MKEY configuration work request was cre-
ated by mlx5dv_wr_mkey_configure().
repeat_count
The data layout representation is repeated repeat_count
times.
num_interleaved
Number of entries in the data representation.
data Pointer to the list of interleaved data layout descrip-
tions.
Interleaved data layout is described by mlx5dv_mr_interleaved
structure.
struct mlx5dv_mr_interleaved {
uint64_t addr;
uint32_t bytes_count;
uint32_t bytes_skip;
uint32_t lkey;
};
addr Start address of the local memory buffer.
bytes_count
Number of data bytes to put into the buffer.
bytes_skip
Number of bytes to skip in the buffer before the next da-
ta block.
lkey Key of the local Memory Region
Signature setters
The signature attributes of the MKEY allow adding/modifying/strip-
ping/validating integrity fields when transmitting data from memory to
network and when receiving data from network to memory.
Use the signature setters to set/update the signature attributes of the
MKEY. To reset the signature attributes without invalidating the MKEY,
use the MLX5DV_MKEY_CONF_FLAG_RESET_SIG_ATTR flag.
mlx5dv_wr_set_mkey_sig_block()
Set MKEY block signature attributes. If the MKEY is already
configured with the signature attributes, the setter overrides
the previous value. See dedicated man page for
mlx5dv_wr_set_mkey_sig_block(3).
Crypto setter
The crypto attributes of the MKey allow encryption and decryption of
transmitted data from memory to network and when receiving data from
network to memory.
Use the crypto setter to set/update the crypto attributes of the MKey.
When the MKey is created with MLX5DV_MKEY_INIT_ATTR_FLAGS_CRYPTO it
must be configured with crypto attributes before the MKey can be used.
mlx5dv_wr_set_mkey_crypto()
Set MKey crypto attributes. If the MKey is already configured
with crypto attributes, the setter overrides the previous value.
see dedicated man page for mlx5dv_wr_set_mkey_crypto(3).
EXAMPLES
Create QP and MKEY
Code below creates a QP with MKEY configure operation support and an
indirect mkey.
/* Create QP with MKEY configure support */
struct ibv_qp_init_attr_ex attr_ex = {};
attr_ex.comp_mask |= IBV_QP_INIT_ATTR_SEND_OPS_FLAGS;
attr_ex.send_ops_flags |= IBV_QP_EX_WITH_RDMA_WRITE;
struct mlx5dv_qp_init_attr attr_dv = {};
attr_dv.comp_mask |= MLX5DV_QP_INIT_ATTR_MASK_SEND_OPS_FLAGS;
attr_dv.send_ops_flags = MLX5DV_QP_EX_WITH_MKEY_CONFIGURE;
ibv_qp *qp = mlx5dv_create_qp(ctx, attr_ex, attr_dv);
ibv_qp_ex *qpx = ibv_qp_to_qp_ex(qp);
mlx5dv_qp_ex *mqpx = mlx5dv_qp_ex_from_ibv_qp_ex(qpx);
mkey_attr.create_flags = MLX5DV_MKEY_INIT_ATTR_FLAGS_INDIRECT;
struct mlx5dv_mkey *mkey = mlx5dv_create_mkey(&mkey_attr);
List data layout configuration
Code below configures an MKEY which allows remote access for read and
write and is based on SGE list layout with two entries. When this MKEY
is used in RDMA write operation, data will be scattered between two
memory regions. The first 64 bytes will go to memory referenced by
mr1. The next 4096 bytes will go to memory referenced by mr2.
ibv_wr_start(qpx);
qpx->wr_id = my_wr_id_1;
qpx->wr_flags = IBV_SEND_INLINE;
struct mlx5dv_mkey_conf_attr mkey_attr = {};
mlx5dv_wr_mkey_configure(mqpx, mkey, 2, &mkey_attr);
mlx5dv_wr_set_mkey_access_flags(mqpx, IBV_ACCESS_REMOTE_READ | IBV_ACCESS_REMOTE_WRITE);
struct ibv_sge sgl[2];
sgl[0].addr = mr1->addr;
sgl[0].length = 64;
sgl[0].lkey = mr1->lkey;
sgl[1].addr = mr2->addr;
sgl[1].length = 4096;
sgl[1].lkey = mr2->lkey;
mlx5dv_wr_set_mkey_layout_list(mqpx, 2, sgl);
ret = ibv_wr_complete(qpx);
Interleaved data layout configuration
Code below configures an MKEY which allows remote access for read and
write and is based on interleaved data layout with two entries and re-
peat count of two. When this MKEY is used in RDMA write operation, da-
ta will be scattered between two memory regions. The first 512 bytes
will go to memory referenced by mr1 at offset 0. The next 8 bytes will
go to memory referenced by mr2 at offset 0. The next 512 bytes will go
to memory referenced by mr1 at offset 516. The next 8 bytes will go to
memory referenced by mr2 at offset 8.
ibv_wr_start(qpx);
qpx->wr_id = my_wr_id_1;
qpx->wr_flags = IBV_SEND_INLINE;
struct mlx5dv_mkey_conf_attr mkey_attr = {};
mlx5dv_wr_mkey_configure(mqpx, mkey, 2, &mkey_attr);
mlx5dv_wr_set_mkey_access_flags(mqpx, IBV_ACCESS_REMOTE_READ | IBV_ACCESS_REMOTE_WRITE);
struct mlx5dv_mr_interleaved data[2];
data[0].addr = mr1->addr;
data[0].bytes_count = 512;
data[0].bytes_skip = 4;
data[0].lkey = mr1->lkey;
data[1].addr = mr2->addr;
data[1].bytes_count = 8;
data[1].bytes_skip = 0;
data[1].lkey = mr2->lkey;
mlx5dv_wr_set_mkey_layout_interleaved(mqpx, 2, 2, &data);
ret = ibv_wr_complete(qpx);
NOTES
A DEVX context should be opened by using mlx5dv_open_device(3).
SEE ALSO
mlx5dv_create_mkey(3), mlx5dv_create_qp(3),
mlx5dv_wr_set_mkey_sig_block(3), mlx5dv_wr_set_mkey_crypto(3)
AUTHORS
Oren Duer <oren@nvidia.com>
Sergey Gorenko <sergeygo@nvidia.com>
Evgenii Kochetov <evgeniik@nvidia.com>
mlx5dv_wr_mkey_configure(3)
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