[PATCH 0/2] lib/crypto: x86/chacha: Add 16-block AVX-512 implementation

[Antonio Quartulli]

Hi all,

this series adds a 16-block ChaCha implementation for x86 using 512-bit
registers. It is preceded by a KUnit suite and benchmark for
chacha_crypt(), as lib/crypto has none for plain ChaCha yet.

Patch 1 stands on its own and passes with and without patch 2.

On AMD Zen 5, the new code doubles chacha_crypt() throughput for inputs
of 1 KiB and more, from about 5.2 GB/s to about 10.2 GB/s. It came out
of work on the OpenVPN data channel offload driver (ovpn), whose
ChaCha20-Poly1305 throughput is CPU-bound: in a VM benchmark it gained
about 10% at a 1500-byte MTU and 35% at 9000.

iPlease note that I could only measure Zen 5.
The new code is not used on the CPUs setting X86_FEATURE_PREFER_YMM
(Skylake-X, Ice Lake and Tiger Lake), but it is on
Rocket Lake, Sapphire Rapids and later, and on Zen 4, where 512-bit
operations are split into two halves. Numbers from any of those would be
very welcome.

Regards,
	Antonio

Antonio Quartulli (2):
  lib/crypto: tests: Add KUnit tests and benchmark for ChaCha
  lib/crypto: x86/chacha: Add 16-block AVX-512 (zmm) implementation

 lib/crypto/.kunitconfig                 |   1 +
 lib/crypto/tests/Kconfig                |   8 +
 lib/crypto/tests/Makefile               |   1 +
 lib/crypto/tests/chacha_kunit.c         | 269 +++++++++++++++
 lib/crypto/x86/chacha-avx512vl-x86_64.S | 413 +++++++++++++++++++++++-
 lib/crypto/x86/chacha.h                 |  29 +-
 6 files changed, 719 insertions(+), 2 deletions(-)
 create mode 100644 lib/crypto/tests/chacha_kunit.c


base-commit: 20ec6916d8712e84d58e8c688a25cd368ddeb82b
-- 
2.55.0