[PATCH 0/6] crypto: x86_64 optimized XChaCha and NHPoly1305 (for Adiantum)

From: Eric Biggers
Date: Wed Nov 28 2018 - 01:48:00 EST


This series optimizes the Adiantum encryption mode for x86_64 by adding
SSE2 and AVX2 accelerated implementations of NHPoly1305, specifically
the NH part; and by modifying the existing x86_64 SSSE3/AVX2 ChaCha20
implementation to support XChaCha20 and XChaCha12.

This greatly improves Adiantum performance on x86_64. For example, with
a 4096-byte input size on a Zen-based processor, which supports AVX2:

Before After
-------- ---------
adiantum(xchacha12,aes) 505 MB/s 1250 MB/s
adiantum(xchacha20,aes) 387 MB/s 989 MB/s

Encryption and decryption are the same speed.

The biggest benefit comes from accelerating XChaCha. Accelerating NH
gives a somewhat smaller, but still significant benefit.

Performance on 512-byte inputs is also improved, though that is much
slower in the first place. When Adiantium is used with dm-crypt (or
cryptsetup), we recommend using a 4096-byte sector size.

For comparison, AES-256-XTS is 4140 MB/s on the same processor, but it
has the benefit of direct AES-NI hardware support for AES whereas
Adiantum is implemented entirely with general-purpose instructions
(scalar and SIMD). The corresponding C implementation of AES-256-XTS is
only 288 MB/s, and AES isn't particularly well-suited for optimizing
with general-purpose SIMD instructions. Also unlike Adiantum, XTS isn't
a super-pseudorandom permutation over the entire sector.

Note that XChaCha20 and XChaCha12 can be used for other purposes too.

Eric Biggers (6):
crypto: x86/nhpoly1305 - add SSE2 accelerated NHPoly1305
crypto: x86/nhpoly1305 - add AVX2 accelerated NHPoly1305
crypto: x86/chacha20 - limit the preemption-disabled section
crypto: x86/chacha20 - add XChaCha20 support
crypto: x86/chacha20 - refactor to allow varying number of rounds
crypto: x86/chacha - add XChaCha12 support

arch/x86/crypto/Makefile | 13 +-
...a20-avx2-x86_64.S => chacha-avx2-x86_64.S} | 33 ++-
...0-ssse3-x86_64.S => chacha-ssse3-x86_64.S} | 99 +++++---
arch/x86/crypto/chacha20_glue.c | 168 -------------
arch/x86/crypto/chacha_glue.c | 236 ++++++++++++++++++
arch/x86/crypto/nh-avx2-x86_64.S | 157 ++++++++++++
arch/x86/crypto/nh-sse2-x86_64.S | 123 +++++++++
arch/x86/crypto/nhpoly1305-avx2-glue.c | 77 ++++++
arch/x86/crypto/nhpoly1305-sse2-glue.c | 76 ++++++
crypto/Kconfig | 28 ++-
10 files changed, 778 insertions(+), 232 deletions(-)
rename arch/x86/crypto/{chacha20-avx2-x86_64.S => chacha-avx2-x86_64.S} (97%)
rename arch/x86/crypto/{chacha20-ssse3-x86_64.S => chacha-ssse3-x86_64.S} (93%)
delete mode 100644 arch/x86/crypto/chacha20_glue.c
create mode 100644 arch/x86/crypto/chacha_glue.c
create mode 100644 arch/x86/crypto/nh-avx2-x86_64.S
create mode 100644 arch/x86/crypto/nh-sse2-x86_64.S
create mode 100644 arch/x86/crypto/nhpoly1305-avx2-glue.c
create mode 100644 arch/x86/crypto/nhpoly1305-sse2-glue.c