Re: [PATCH v3 01/21] x86/cpufreatures: add AMD Collaborative Processor Performance Control feature flag

From: Borislav Petkov
Date: Sat Nov 06 2021 - 06:29:39 EST


On Fri, Oct 29, 2021 at 09:02:21PM +0800, Huang Rui wrote:
> Add Collaborative Processor Performance Control feature flag for AMD
> processors.
>
> This feature flag will be used on the following amd-pstate driver. The
> amd-pstate driver has two approaches to implement the frequency control
> behavior. That depends on the CPU hardware implementation. One is "Full
> MSR Support" and another is "Shared Memory Support". The feature flag
> indicates the current processors with "Full MSR Support".
>
> Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
> ---
> arch/x86/include/asm/cpufeatures.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> index d0ce5cfd3ac1..f23dc1abd485 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -313,6 +313,7 @@
> #define X86_FEATURE_AMD_SSBD (13*32+24) /* "" Speculative Store Bypass Disable */
> #define X86_FEATURE_VIRT_SSBD (13*32+25) /* Virtualized Speculative Store Bypass Disable */
> #define X86_FEATURE_AMD_SSB_NO (13*32+26) /* "" Speculative Store Bypass is fixed in hardware. */
> +#define X86_FEATURE_AMD_CPPC (13*32+27) /* Collaborative Processor Performance Control */

I know I have acked this already but an Intel patchset made me look at
this again: there's no need to have the vendor name in the feature name:

X86_FEATURE_CPPC

is perfectly fine.

--
Regards/Gruss,
Boris.

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