Re: [PATCH V2 1/6] x86: Add AMD HW_PSTATE cpu feature bit and MSRs

[Borislav Petkov <bp@alien8.de>]

On Fri, Jun 17, 2011 at 03:50:52PM -0400, Matthew Garrett wrote:
> AMD CPUs that support hardware P-state setting expose this via cpuid. Add
> the bit to the generic code so the ACPI cpufreq driver can make use of it,
> and also add the related MSRs.
> 
> Signed-off-by: Matthew Garrett <mjg@redhat.com>
> ---
>  arch/x86/include/asm/cpufeature.h |    1 +
>  arch/x86/include/asm/msr-index.h  |    2 ++
>  arch/x86/kernel/cpu/scattered.c   |    1 +
>  3 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
> index 71cc380..312f455 100644
> --- a/arch/x86/include/asm/cpufeature.h
> +++ b/arch/x86/include/asm/cpufeature.h
> @@ -174,6 +174,7 @@
>  #define X86_FEATURE_PLN		(7*32+ 5) /* Intel Power Limit Notification */
>  #define X86_FEATURE_PTS		(7*32+ 6) /* Intel Package Thermal Status */
>  #define X86_FEATURE_DTS		(7*32+ 7) /* Digital Thermal Sensor */
> +#define X86_FEATURE_HW_PSTATE	(7*32+ 8) /* AMD frequency scaling */

Yeah, this is actually called			  /* AMD hardware P-state control */

because older CPUs also do frequency scaling but use a different method.

Other than that

Acked-by: Borislav Petkov <borislav.petkov@amd.com>

>  
>  /* Virtualization flags: Linux defined, word 8 */
>  #define X86_FEATURE_TPR_SHADOW  (8*32+ 0) /* Intel TPR Shadow */
> diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
> index 485b4f1..1772978 100644
> --- a/arch/x86/include/asm/msr-index.h
> +++ b/arch/x86/include/asm/msr-index.h
> @@ -234,6 +234,8 @@
>  
>  #define MSR_IA32_PERF_STATUS		0x00000198
>  #define MSR_IA32_PERF_CTL		0x00000199
> +#define MSR_AMD_PERF_STATUS		0xc0010063
> +#define MSR_AMD_PERF_CTL		0xc0010062
>  
>  #define MSR_IA32_MPERF			0x000000e7
>  #define MSR_IA32_APERF			0x000000e8
> diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
> index c7f64e6..4adffc4 100644
> --- a/arch/x86/kernel/cpu/scattered.c
> +++ b/arch/x86/kernel/cpu/scattered.c
> @@ -39,6 +39,7 @@ void __cpuinit init_scattered_cpuid_features(struct cpuinfo_x86 *c)
>  		{ X86_FEATURE_APERFMPERF,	CR_ECX, 0, 0x00000006, 0 },
>  		{ X86_FEATURE_EPB,		CR_ECX, 3, 0x00000006, 0 },
>  		{ X86_FEATURE_XSAVEOPT,		CR_EAX,	0, 0x0000000d, 1 },
> +		{ X86_FEATURE_HW_PSTATE,	CR_EDX, 7, 0x80000007, 0 },
>  		{ X86_FEATURE_CPB,		CR_EDX, 9, 0x80000007, 0 },
>  		{ X86_FEATURE_NPT,		CR_EDX, 0, 0x8000000a, 0 },
>  		{ X86_FEATURE_LBRV,		CR_EDX, 1, 0x8000000a, 0 },
> -- 
> 1.7.5.2
> 
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-- 
Regards/Gruss,
    Boris.