mlx5dv_wr_set_mkey_sig_block(3) mlx5dv_wr_set_mkey_sig_block(3)
NAME
mlx5dv_wr_set_mkey_sig_block - Configure a MKEY for block signature
(data integrity) operation.
SYNOPSIS
#include <infiniband/mlx5dv.h>
static inline void mlx5dv_wr_set_mkey_sig_block(struct mlx5dv_qp_ex *mqp,
const struct mlx5dv_sig_block_attr *attr)
DESCRIPTION
Configure a MKEY with block-level data protection properties. With
this, the device can add/modify/strip/validate integrity fields per
block when transmitting data from memory to network and when receiving
data from network to memory.
This setter can be optionally called after a MKEY configuration work
request posting has started using mlx5dv_wr_mkey_configure(3). Config-
uring block signature properties to a MKEY is done by describing what
kind of signature is required (or expected) in two domains: the wire
domain and the memory domain.
The MKEY represents a virtually contiguous memory, by configuring a
layout to it. The memory signature domain describes whether data in
this virtually contiguous memory includes integrity fields, and if so,
what kind and what block size.
The wire signature domain describes the same kind of properties for the
data as it is seen on the wire. Now, depending on the actual operation
that happens (TX or RX), the device will do the “right thing” based on
the signature configurations of the two domains.
Example 1:
Memory signature domain is configured for CRC32 every 512B block.
Wire signature domain is configured for no signature.
A SEND is issued using the MKEY as a local key.
Result: device will gather the data with the CRC32 fields from the MKEY
(using whatever layout configured to the MKEY to locate the actual mem-
ory), validate each CRC32 against the previous 512 bytes of data, strip
the CRC32 field, and transmit only 512 bytes of data to the wire.
Example 1.1:
Same as above, but a RECV is issued with the same key, and RX happens.
Result: device will receive the data from the wire, scatter it to the
MKEY (using whatever layout configured to the MKEY to locate the actual
memory), generating and scattering additional CRC32 field after every
512 bytes that are scattered.
Example 2:
Memory signature domain is configured for no signature.
Wire signature domain is configured for T10DIF every 4K block.
The MKEY is sent to a remote node that issues a RDMA_READ to this MKEY.
Result: device will gather the data from the MKEY (using whatever lay-
out configured to the MKEY to locate the actual memory), transmit it to
the wire while generating an additional T10DIF field every 4K of data.
Example 2.1:
Same as above, but remote node issues a RDMA_WRITE to this MKEY.
Result: Device will receive the data from the wire, validate each
T10DIF field against the previous 4K of data, strip the T10DIF field,
and scatter the data alone to the MKEY (using whatever layout config-
ured to the MKEY to locate the actual memory).
ARGUMENTS
mqp
The QP where an MKEY configuration work request was created by
mlx5dv_wr_mkey_configure().
attr Block signature attributes to set for the MKEY.
Block signature attributes
Block signature attributes describe the input and output data struc-
tures in memory and wire domains.
struct mlx5dv_sig_block_attr {
const struct mlx5dv_sig_block_domain *mem;
const struct mlx5dv_sig_block_domain *wire;
uint32_t flags;
uint8_t check_mask;
uint8_t copy_mask;
uint64_t comp_mask;
};
mem A pointer to the signature configuration for the memory domain
or NULL if the domain does not have a signature.
wire A pointer to the signature configuration for the wire domain or
NULL if the domain does not have a signature.
flags A bitwise OR of the various values described below.
MLX5DV_SIG_BLOCK_ATTR_FLAG_COPY_MASK
If the bit is not set then copy_mask is ignored. See de-
tails in the copy_mask description.
check_mask
Each bit of check_mask corresponds to a byte of the signature
field in input domain. Byte of the input signature is checked
if corresponding bit in check_mask is set. Bits not relevant to
the signature type are ignored.
Layout of check_mask.
check_mask 7 6 5 4 3 2 1 0
(bits)
─────────────────────────────────────────────────────────────────────────────────────────────────
T10-DIF (bytes) GUARD[1] GUARD[0] APP[1] APP[0] REF[3] REF[2] REF[1] REF[0]
CRC32C/CRC32 3 2 1 0
(bytes)
CRC64_XP10 7 6 5 4 3 2 1 0
(bytes)
Common used masks are defined in enum mlx5dv_sig_mask. Other
masks are also supported. Follow the above table to define a
custom mask. For example, this can be useful for the applica-
tion tag field of the T10DIF signature. Using the application
tag is out of the scope of the T10DIF specification and depends
on the implementation. check_mask allows validating a part of
the application tag if needed.
copy_mask
A mask to specify what part of the signature is copied from the
source domain to the destination domain. The copy mask is usu-
ally calculated automatically. The signature is copied if the
same signature type is configurted on both domains. The parts
of the T10-DIF are compared and handled independetly.
If MLX5DV_SIG_BLOCK_ATTR_FLAG_COPY_MASK is set the copy_mask at-
tribute overrides the calculated value of the copy mask. Other-
wise, copy_mask is ignored.
Each bit of copy_mask corresponds to a byte of the signature
field. If corresponding bit in copy_mask is set, byte of the
signature is copied from the input domain to the output domain.
Calculation according to the output domain configuration is not
performed in this case. Bits not relevant to the signature type
are ignored. copy_mask may be used only if input and output do-
mains have the same structure, i.e. same block size and signa-
ture type. The MKEY configuration will fail if
MLX5DV_SIG_BLOCK_ATTR_FLAG_COPY_MASK is set but the domains have
different signature structures.
The predefined masks are available in enum mlx5dv_sig_mask. It
is also supported to specify a user-defined mask. Follow the
table in check_mask description to define a custom mask.
copy_mask can be useful when some bytes of the signature are not
known in advance, hence can’t be checked, but shall be pre-
served. In this case corresponding bits should be cleared in
check_mask and set in copy_mask.
comp_mask
Reserved for future extension, must be 0 now.
Block signature domain
struct mlx5dv_sig_block_domain {
enum mlx5dv_sig_type sig_type;
union {
const struct mlx5dv_sig_t10dif *dif;
const struct mlx5dv_sig_crc *crc;
} sig;
enum mlx5dv_block_size block_size;
uint64_t comp_mask;
};
sig_type
The signature type for this domain, one of the following
MLX5DV_SIG_TYPE_T10DIF
The block-level data protection defined in the T10 speci-
fications (T10 SBC-3).
MLX5DV_SIG_TYPE_CRC
The block-level data protection based on cyclic redundan-
cy check (CRC). The specific type of CRC is defined in
sig.
sig Depending on sig_type, this is the per signature type specific
configuration.
block_size
The block size for this domain, one of enum
mlx5dv_sig_block_size.
comp_mask
Reserved for future extension, must be 0 now.
CRC signature
struct mlx5dv_sig_crc {
enum mlx5dv_sig_crc_type type;
uint64_t seed;
};
type The specific CRC type, one of the following.
MLX5DV_SIG_CRC_TYPE_CRC32
CRC32 signature is created by calculating a 32-bit CRC
defined in Fibre Channel Physical and Signaling Interface
(FC-PH), ANSI X3.230:1994.
MLX5DV_SIG_CRC_TYPE_CRC32C
CRC32C signature is created by calculating a 32-bit CRC
called the Castagnoli CRC, defined in the Internet Small
Computer Systems Interface (iSCSI) rfc3720.
MLX5DV_SIG_CRC_TYPE_CRC64_XP10
CRC64_XP10 signature is created by calculating a 64-bit
CRC defined in Microsoft XP10 compression standard.
seed A seed for the CRC calculation per block. Bits not relevant to
the CRC type are ignored. For example, all bits are used for
CRC64_XP10, but only the 32 least significant bits are used for
CRC32/CRC32C.
Only the following values are supported as a seed: CRC32/CRC32C
- 0, 0xFFFFFFFF(UINT32_MAX); CRC64_XP10 - 0,
0xFFFFFFFFFFFFFFFF(UINT64_MAX).
T10DIF signature
T10DIF signature is defined in the T10 specifications (T10 SBC-3) for
block-level data protection. The size of data block protected by
T10DIF must be modulo 8bytes as required in the T10DIF specifications.
Note that when setting the initial LBA value to ref_tag, it should be
the value of the first block to be transmitted.
struct mlx5dv_sig_t10dif {
enum mlx5dv_sig_t10dif_bg_type bg_type;
uint16_t bg;
uint16_t app_tag;
uint32_t ref_tag;
uint16_t flags;
};
bg_type
The block guard type to be used, one of the following.
MLX5DV_SIG_T10DIF_CRC
Use CRC in the block guard field as required in the
T10DIF specifications.
MLX5DV_SIG_T10DIF_CSUM
Use IP checksum instead of CRC in the block guard field.
bg A seed for the block guard calculation per block.
The following values are supported as a seed: 0,
0xFFFF(UINT16_MAX).
app_tag
An application tag to generate or validate.
ref_tag
A reference tag to generate or validate.
flags Flags for the T10DIF attributes, one of the following.
MLX5DV_SIG_T10DIF_FLAG_REF_REMAP
Increment reference tag per block.
MLX5DV_SIG_T10DIF_FLAG_APP_ESCAPE
Do not check block guard if application tag is 0xFFFF.
MLX5DV_SIG_T10DIF_FLAG_APP_REF_ESCAPE
Do not check block guard if application tag is 0xFFFF and
reference tag is 0xFFFFFFFF.
RETURN VALUE
This function does not return a value.
In case of error, user will be notified later when completing the DV
WRs chain.
Notes
A DEVX context should be opened by using mlx5dv_open_device(3).
MKEY must be created with MLX5DV_MKEY_INIT_ATTR_FLAGS_BLOCK_SIGNATURE
flag.
The last operation posted on the supplied QP should be
mlx5dv_wr_mkey_configure(3), or one of its related setters, and the op-
eration must still be open (no doorbell issued).
In case of ibv_wr_complete() failure or calling to ibv_wr_abort(), the
MKey may be left in an unknown state. The next configuration of it
should not assume any previous state of the MKey, i.e. signature/crypto
should be re-configured or reset, as required. For example, assuming
mlx5dv_wr_set_mkey_sig_block() and then ibv_wr_abort() were called,
then on the next configuration of the MKey, if signature is not needed,
it should be reset using MLX5DV_MKEY_CONF_FLAG_RESET_SIG_ATTR.
SEE ALSO
mlx5dv_wr_mkey_configure(3), mlx5dv_create_mkey(3), mlx5dv_de-
stroy_mkey(3)
AUTHORS
Oren Duer <oren@nvidia.com>
Sergey Gorenko <sergeygo@nvidia.com>
mlx5dv_wr_set_mkey_sig_block(3)
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