1. 08 Jan, 2021 1 commit
    • Ard Biesheuvel's avatar
      crypto: x86/aes-ni-xts - use direct calls to and 4-way stride · 86ad60a6
      Ard Biesheuvel authored
      The XTS asm helper arrangement is a bit odd: the 8-way stride helper
      consists of back-to-back calls to the 4-way core transforms, which
      are called indirectly, based on a boolean that indicates whether we
      are performing encryption or decryption.
      
      Given how costly indirect calls are on x86, let's switch to direct
      calls, and given how the 8-way stride doesn't really add anything
      substantial, use a 4-way stride instead, and make the asm core
      routine deal with any multiple of 4 blocks. Since 512 byte sectors
      or 4 KB blocks are the typical quantities XTS operates on, increase
      the stride exported to the glue helper to 512 bytes as well.
      
      As a result, the number of indirect calls is reduced from 3 per 64 bytes
      of in/output to 1 per 512 bytes of in/output, which produces a 65% speedup
      when operating on 1 KB blocks (measured on a Intel(R) Core(TM) i7-8650U CPU)
      
      Fixes: 9697fa39 ("x86/retpoline/crypto: Convert crypto assembler indirect jumps")
      Tested-by: Eric Biggers <ebiggers@google.com> # x86_64
      Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      86ad60a6
  2. 02 Jan, 2021 39 commits