Re: [PATCH v3 1/2] x86/cpufeatures: Add AMD FAST CPPC feature flag

Dave Hansen
2024-05-23T16:31:54Z

On 5/22/24 23:16, Xiaojian Du wrote:
> #define X86_FEATURE_BHI_CTRL (21*32+ 2) /* "" BHI_DIS_S HW control available */
> #define X86_FEATURE_CLEAR_BHB_HW (21*32+ 3) /* "" BHI_DIS_S HW control enabled */
> #define X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT (21*32+ 4) /* "" Clear branch history at vmexit using SW loop */
> +#define X86_FEATURE_FAST_CPPC (21*32 + 5) /* "" AMD Fast CPPC */

It'd be nice to expand the CPPC acronym at least _once_.

Also, this is used _once_ at boot and not exposed in /proc/cpuinfo. Is
it even worth defining an X86_FEATURE_ for it?