This Advanced Encryption Standard (AES) with Galois/Counter Mode (GCM) work has squeezed some nice performance gains out of various Intel and AMD processors for Linux 6.19. For example, the AES-GCM work can deliver up to ~74% faster performance on AMD Zen 3 .
Eric Biggers explained in the AES-GCM optimization pull request :
"More optimizations and cleanups for the x86_64 AES-GCM code:
- Add a VAES+AVX2 optimized implementation of AES-GCM. This is very helpful on CPUs that have VAES but not AVX512, such as AMD Zen 3.
- Make the VAES+AVX512 optimized implementation of AES-GCM handle large amounts of associated data efficiently.
- Remove the "avx10_256" implementation of AES-GCM. It's superseded by the VAES+AVX2 optimized implementation.
- Rename the "avx10_512" implementation to "avx512".
Overall, this fills in a gap where AES-GCM wasn't fully optimized on some recent CPUs. It also drops code that won't be as useful as initially expected due to AVX10/256 being dropped from the AVX10 spec."
Additionally, Biggers submitted and was since merged all the crypto library updates. The work there includes adding SHA-3 support, BLAKE2b support is also added to the lib/crypto code, and POLYVAL support is also added to. SHA-3 was motivated as part of the ML-DSA signature algorithm work for kernel modules, BLAKE2b can be used by Btrfs for checksums, and the POLYVAL work yields code simplification compared to the current code.