Re: [PATCH v8 2/5] x86/cpuid: Add generic table for cpuid dependencies

From: Thomas Gleixner
Date: Thu Oct 05 2017 - 18:45:29 EST


On Thu, 5 Oct 2017, Andi Kleen wrote:
> +/*
> + * Table of CPUID features that depend on others.
> + *
> + * This only includes dependencies that can be usefully disabled, not
> + * features part of the base set (like FPU).
> + */
> +const static struct cpuid_dep cpuid_deps[] = {
> + { X86_FEATURE_XSAVEOPT, X86_FEATURE_XSAVE },
> + { X86_FEATURE_XSAVEC, X86_FEATURE_XSAVE },
> + { X86_FEATURE_XSAVES, X86_FEATURE_XSAVE },
> + { X86_FEATURE_AVX, X86_FEATURE_XSAVE },
> + { X86_FEATURE_AVX512F, X86_FEATURE_XSAVE },

This looks redundant. AVX512F depends on AVX which itself depends on XSAVE.

> + { X86_FEATURE_PKU, X86_FEATURE_XSAVE },
> + { X86_FEATURE_MPX, X86_FEATURE_XSAVE },
> + { X86_FEATURE_XGETBV1, X86_FEATURE_XSAVE },
> + { X86_FEATURE_XMM2, X86_FEATURE_XMM },

XMM has no dependency?

Thanks,

tglx