Re: [PATCH v2 0/6] Optimize fsverity using 2-way interleaved SHA-256 hashing

[Eric Biggers <ebiggers@kernel.org>]

On Mon, Sep 15, 2025 at 11:08:13AM -0500, Eric Biggers wrote:
> This series is targeting libcrypto-next.  It can also be retrieved from:
> 
>     git fetch https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git sha256_finup_2x-v2
> 
> This series adds support for 2-way interleaved SHA-256 hashing to
> lib/crypto/, implements it for arm64 and x86_64, and makes fsverity use
> it.  This significantly improves fsverity performance on many CPUs.
> 
> Later patches will make dm-verity use this optimization as well.
> 
> Changed in v2:
> - Made the new arm64 assembly compatible with CONFIG_CPU_BIG_ENDIAN=y.
> - Omitted sha256_finup_2x() from pre-boot environments.
> - Made alloc_guarded_buf() assert that the allocation succeeded.
> - Minor tweaks to comments and whitespace.
> 
> Eric Biggers (6):
>   lib/crypto: sha256: Add support for 2-way interleaved hashing
>   lib/crypto: arm64/sha256: Add support for 2-way interleaved hashing
>   lib/crypto: x86/sha256: Add support for 2-way interleaved hashing
>   lib/crypto: tests: Add tests and benchmark for sha256_finup_2x()
>   fsverity: Remove inode parameter from fsverity_hash_block()
>   fsverity: Use 2-way interleaved SHA-256 hashing when supported
> 
>  fs/verity/enable.c              |  12 +-
>  fs/verity/fsverity_private.h    |   2 +-
>  fs/verity/hash_algs.c           |   3 +-
>  fs/verity/verify.c              | 175 ++++++++++++---
>  include/crypto/sha2.h           |  28 +++
>  lib/crypto/arm64/sha256-ce.S    | 284 +++++++++++++++++++++++-
>  lib/crypto/arm64/sha256.h       |  37 ++++
>  lib/crypto/sha256.c             |  71 +++++-
>  lib/crypto/tests/sha256_kunit.c | 184 ++++++++++++++++
>  lib/crypto/x86/sha256-ni-asm.S  | 368 ++++++++++++++++++++++++++++++++
>  lib/crypto/x86/sha256.h         |  39 ++++
>  11 files changed, 1147 insertions(+), 56 deletions(-)

FYI, applied to https://git.kernel.org/pub/scm/fs/fsverity/linux.git/log/?h=for-next

I decided to use the fsverity tree instead of the libcrypto one.  There
are no dependencies on other libcrypto changes for 6.18, and this makes
it easier to do a separate pull request.

Also, as always, reviews and acks would be appreciated!  Note that I
dropped the reviews and acks that were on the original crypto_shash
version from earlier this year, due to changes in the patches.  The
high-level idea is still the same, though.  If people could
re-review/ack this latest version, that would be great.  Thanks,

- Eric