linux-kernel - RE: [RESEND PATCH V2 4/9] x86/msr: Add the MSR definition for AMD CPPC boost state

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Date:   Thu, 20 Oct 2022 16:01:09 +0000
From:   "Yuan, Perry" <Perry.Yuan@....com>
To:     "Huang, Ray" <Ray.Huang@....com>
CC:     "rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
        "viresh.kumar@...aro.org" <viresh.kumar@...aro.org>,
        "Sharma, Deepak" <Deepak.Sharma@....com>,
        "Limonciello, Mario" <Mario.Limonciello@....com>,
        "Fontenot, Nathan" <Nathan.Fontenot@....com>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Huang, Shimmer" <Shimmer.Huang@....com>,
        "Du, Xiaojian" <Xiaojian.Du@....com>,
        "Meng, Li (Jassmine)" <Li.Meng@....com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [RESEND PATCH V2 4/9] x86/msr: Add the MSR definition for AMD
 CPPC boost state

[AMD Official Use Only - General]

Hi Ray. 

> -----Original Message-----
> From: Huang, Ray <Ray.Huang@....com>
> Sent: Monday, October 17, 2022 5:57 PM
> To: Yuan, Perry <Perry.Yuan@....com>
> Cc: rafael.j.wysocki@...el.com; viresh.kumar@...aro.org; Sharma, Deepak
> <Deepak.Sharma@....com>; Limonciello, Mario
> <Mario.Limonciello@....com>; Fontenot, Nathan
> <Nathan.Fontenot@....com>; Deucher, Alexander
> <Alexander.Deucher@....com>; Huang, Shimmer
> <Shimmer.Huang@....com>; Du, Xiaojian <Xiaojian.Du@....com>; Meng,
> Li (Jassmine) <Li.Meng@....com>; linux-pm@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Subject: Re: [RESEND PATCH V2 4/9] x86/msr: Add the MSR definition for
> AMD CPPC boost state
> 
> On Tue, Oct 11, 2022 at 12:22:43AM +0800, Yuan, Perry wrote:
> > This MSR can be used to check whether the CPU frequency boost state is
> > enabled in the hardware control. User can change the boost state in
> > the BIOS setting,amd_pstate driver will update the boost state
> > according to this msr value.
> >
> > AMD Processor Programming Reference (PPR)
> > Link: https://www.amd.com/system/files/TechDocs/40332.pdf [p1095]
> > Link: https://www.amd.com/system/files/TechDocs/56569-A1-PUB.zip
> > [p162]
> >
> > Signed-off-by: Perry Yuan <Perry.Yuan@....com>
> > ---
> >  arch/x86/include/asm/msr-index.h | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/arch/x86/include/asm/msr-index.h
> > b/arch/x86/include/asm/msr-index.h
> > index 6674bdb096f3..e5ea1c9f747b 100644
> > --- a/arch/x86/include/asm/msr-index.h
> > +++ b/arch/x86/include/asm/msr-index.h
> > @@ -569,6 +569,7 @@
> >  #define MSR_AMD_CPPC_CAP2		0xc00102b2
> >  #define MSR_AMD_CPPC_REQ		0xc00102b3
> >  #define MSR_AMD_CPPC_STATUS		0xc00102b4
> > +#define MSR_AMD_CPPC_HW_CTL		0xc0010015
> >
> >  #define AMD_CPPC_LOWEST_PERF(x)		(((x) >> 0) & 0xff)
> >  #define AMD_CPPC_LOWNONLIN_PERF(x)	(((x) >> 8) & 0xff)
> > @@ -579,6 +580,8 @@
> >  #define AMD_CPPC_MIN_PERF(x)		(((x) & 0xff) << 8)
> >  #define AMD_CPPC_DES_PERF(x)		(((x) & 0xff) << 16)
> >  #define AMD_CPPC_ENERGY_PERF_PREF(x)	(((x) & 0xff) << 24)
> > +#define AMD_CPPC_PRECISION_BOOST_BIT   25
> > +#define AMD_CPPC_PRECISION_BOOST_ENABLED
> BIT_ULL(AMD_CPPC_PRECISION_BOOST_BIT)
> 
> I had commented the MSR_AMD_CPPC_HW_CTL is duplicated with
> MSR_K7_HWCR
> 
> https://lore.kernel.org/lkml/YtX+uF/nAIG0ykHN@amd.com/
> https://lore.kernel.org/lkml/YtX586RDd9Xw44IO@amd.com/
> 
> Could you please make sure address the commments?
> 
> Thanks,
> Ray

If I rename that the MSR definition string, that will cause lots of driver file change. 
So I suggest to add one new MSR macro for the CPPC, the MSR_K7_HWCR is  mismatching in the CPPC Pstate driver.
If you refuse to use this new one, I will reuse that old one. 

Perry.