Power9 processor supports Virtual Accelerator Switchboard (VAS) which
allows kernel and userspace to send compression requests to Nest
Accelerator (NX) directly. The NX unit comprises of 2 842 compression
engines and 1 GZIP engine. Linux kernel already has 842 compression
support on kernel. This patch series adds GZIP compression support
from user space. The GZIP Compression engine implements the ZLIB and
GZIP compression algorithms. No plans of adding NX-GZIP compression
support in kernel right now.
Applications can send requests to NX directly with COPY/PASTE
instructions. But kernel has to establish channel / window on NX-GZIP
device for the userspace. So userspace access to the GZIP engine is
provided through /dev/crypto/nx-gzip device with several operations.
An application must open the this device to obtain a file descriptor (fd).
Using the fd, application should issue the VAS_TX_WIN_OPEN ioctl to
establish a connection to the engine. Once window is opened, should use
mmap() system call to map the hardware address of engine's request queue
into the application's virtual address space. Then user space forms the
request as co-processor Request Block (CRB) and paste this CRB on the
mapped HW address using COPY/PASTE instructions. Application can poll
on status flags (part of CRB) with timeout for request completion.
For VAS_TX_WIN_OPEN ioctl, if user space passes vas_id = -1 (struct
vas_tx_win_open_attr), kernel determines the VAS instance on the
corresponding chip based on the CPU on which the process is executing.
Otherwise, the specified VAS instance is used if application passes the
proper VAS instance (vas_id listed in /proc/device-tree/vas@*/ibm,vas_id).
Process can open multiple windows with different FDs or can send several
requests to NX on the same window at the same time.
A userspace library libnxz is available:
https://github.com/abalib/power-gzip
Applications that use inflate/deflate calls can link with libNXz and use
NX GZIP compression without any modification.
Tested the available 842 compression on power8 and power9 system to make
sure no regression and tested GZIP compression on power9 with tests
available in the above link.
Thanks to Bulent Abali for nxz library and tests development.
Changelog:
V2:
- Move user space API code to powerpc as suggested. Also this API
can be extended to any other coprocessor type that VAS can support
in future. Example: Fast thread wakeup feature from VAS
- Rebased to 5.6-rc3
V3:
- Fix sparse warnings (patches 3&6)
V4:
- Remove unused coproc_instid and add only window address in
fp->private_data.
- Add NX User's manual and Copy/paste links in VAS API documentation
in patch and other changes as Daniel Axtens suggested
V5:
- Added "NX Fault handling" section in VAS API documentation as Nick
suggested.
- Dcoumentation: mmap size should be PAGE_SIZE as Daniel Axtens pointed.
Haren Myneni (9):
powerpc/vas: Initialize window attributes for GZIP coprocessor type
powerpc/vas: Define VAS_TX_WIN_OPEN ioctl API
powerpc/vas: Add VAS user space API
crypto/nx: Initialize coproc entry with kzalloc
crypto/nx: Rename nx-842-powernv file name to nx-common-powernv
crypto/nx: Make enable code generic to add new GZIP compression type
crypto/nx: Enable and setup GZIP compresstion type
crypto/nx: Remove 'pid' in vas_tx_win_attr struct
Documentation/powerpc: VAS API
Documentation/powerpc/index.rst | 1 +
Documentation/powerpc/vas-api.rst | 292 +++++
Documentation/userspace-api/ioctl/ioctl-number.rst | 1 +
arch/powerpc/include/asm/vas.h | 12 +-
arch/powerpc/include/uapi/asm/vas-api.h | 22 +
arch/powerpc/platforms/powernv/Makefile | 2 +-
arch/powerpc/platforms/powernv/vas-api.c | 257 +++++
arch/powerpc/platforms/powernv/vas-window.c | 23 +-
arch/powerpc/platforms/powernv/vas.h | 2 +
drivers/crypto/nx/Makefile | 2 +-
drivers/crypto/nx/nx-842-powernv.c | 1062 ------------------
drivers/crypto/nx/nx-common-powernv.c | 1133 ++++++++++++++++++++
12 files changed, 1736 insertions(+), 1073 deletions(-)
create mode 100644 Documentation/powerpc/vas-api.rst
create mode 100644 arch/powerpc/include/uapi/asm/vas-api.h
create mode 100644 arch/powerpc/platforms/powernv/vas-api.c
delete mode 100644 drivers/crypto/nx/nx-842-powernv.c
create mode 100644 drivers/crypto/nx/nx-common-powernv.c
--
1.8.3.1
