This patchset Introduces Verbs level support for signature handover
feature. Siganture is intended to implement end-to-end data integrity
on a transactional basis in a completely offloaded manner.
There are several end-to-end data integrity methods used today in various
applications and/or upper layer protocols such as T10-DIF defined by SCSI
specifications (SBC), CRC32, XOR8 and more. This patchset adds verbs
support only for T10-DIF. The proposed framework allows adding more
signature methods in the future.
In T10-DIF, when a series of 512-byte data blocks are transferred, each
block is followed by an 8-byte guard. The guard consists of CRC that
protects the integrity of the data in the block, and some other tags
that protects against mis-directed IOs.
Data can be protected when transferred over the wire, but can also be
protected in the memory of the sender/receiver. This allows true end-
to-end protection against bits flipping either over the wire, through
gateways, in memory, over PCI, etc.
While T10-DIF clearly defines that over the wire protection guards are
interleaved into the data stream (each 512-Byte block followed by 8-byte
guard), when in memory, the protection guards may reside in a buffer
separated from the data. Depending on the application, it is usually
easier to handle the data when it is contiguous. In this case the data
buffer will be of size 512xN and the protection buffer will be of size
8xN (where N is the number of blocks in the transaction).
There are 3 kinds of signature handover operation:
1. Take unprotected data (from wire or memory) and ADD protection
guards.
2. Take protetected data (from wire or memory), validate the data
integrity against the protection guards and STRIP the protection
guards.
3. Take protected data (from wire or memory), validate the data
integrity against the protection guards and PASS the data with
the guards as-is.
This translates to defining to the HCA how/if data protection exists
in memory domain, and how/if data protection exists is wire domain.
The way that data integrity is performed is by using a new kind of
memory region: signature-enabled MR, and a new kind of work request:
REG_SIG_MR. The REG_SIG_MR WR operates on the signature-enabled MR,
and defines all the needed information for the signature handover
(data buffer, protection buffer if needed and signature attributes).
The result is an MR that can be used for data transfer as usual,
that will also add/validate/strip/pass protection guards.
When the data transfer is successfully completed, it does not mean
that there are no integrity errors. The user must afterwards check
the signature status of the handover operation using a new light-weight
verb.
This feature shall be used in storage upper layer protocols iSER/SRP
implementing end-to-end data integrity T10-DIF. Following this patchset,
we will soon submit krping patches which will demonstrate the usage of
these signature verbs.
Patchset summary:
- Intoduce verbs for create/destroy memory regions supporting signature.
- Introduce IB core signature verbs API.
- Implement mr create/destroy verbs in mlx5 driver.
- Preperation patches for signature support in mlx5 driver.
- Implement signature handover work request in mlx5 driver.
- Implement signature error collection and handling in mlx5 driver.
Changes from v1:
- IB/core: Reduced sizeof ib_send_wr by using wr->sg_list for data
and dedicated ib_sge for protection guards buffer.
Currently sig_handover extension does not increase sizeof ib_send_wr
- IB/core: Change enum to int for container variables.
- IB/mlx5: Validate wr->num_sge=1 for REG_SIG_MR work request.
Changes from v0:
- Commit messages: Added more detailed explanation for signature work request.
- IB/core: Remove indirect memory registration enablement from create_mr.
Keep only signature enablement.
- IB/mlx5: Changed signature error processing via MR radix lookup.
Sagi Grimberg (10):
IB/core: Introduce protected memory regions
IB/core: Introduce Signature Verbs API
IB/mlx5, mlx5_core: Support for create_mr and destroy_mr
IB/mlx5: Initialize mlx5_ib_qp signature related
IB/mlx5: Break wqe handling to begin & finish routines
IB/mlx5: remove MTT access mode from umr flags helper function
IB/mlx5: Keep mlx5 MRs in a radix tree under device
IB/mlx5: Support IB_WR_REG_SIG_MR
IB/mlx5: Collect signature error completion
IB/mlx5: Publish support in signature feature
drivers/infiniband/core/verbs.c | 47 +++
drivers/infiniband/hw/mlx5/cq.c | 53 +++
drivers/infiniband/hw/mlx5/main.c | 12 +
drivers/infiniband/hw/mlx5/mlx5_ib.h | 14 +
drivers/infiniband/hw/mlx5/mr.c | 138 +++++++
drivers/infiniband/hw/mlx5/qp.c | 525 ++++++++++++++++++++++--
drivers/net/ethernet/mellanox/mlx5/core/main.c | 1 +
drivers/net/ethernet/mellanox/mlx5/core/mr.c | 84 ++++
include/linux/mlx5/cq.h | 1 +
include/linux/mlx5/device.h | 43 ++
include/linux/mlx5/driver.h | 35 ++
include/linux/mlx5/qp.h | 62 +++
include/rdma/ib_verbs.h | 165 ++++++++-
13 files changed, 1141 insertions(+), 39 deletions(-)
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