x86: move ZMM exclusion list into CPU feature flag

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Lift zmm_exclusion_list in aesni-intel_glue.c into the x86 CPU setup
code, and add a new x86 CPU feature flag X86_FEATURE_PREFER_YMM that is
set when the CPU is on this list.

This allows other code in arch/x86/, such as the CRC library code, to
apply the same exclusion list when deciding whether to execute 256-bit
or 512-bit optimized functions.

Note that full AVX512 support including ZMM registers is still exposed
to userspace and is still supported for in-kernel use.  This flag just
indicates whether in-kernel code should prefer to use YMM registers.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250210174540.161705-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

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This commit is contained in:

Eric Biggers 2025-02-10 09:26:44 -08:00

parent 0645b245a2

commit 968e9bc4ce

3 changed files with 24 additions and 21 deletions

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22

arch/x86/crypto/aesni-intel_glue.c

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1

arch/x86/include/asm/cpufeatures.h

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22

arch/x86/kernel/cpu/intel.c

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