linux-kernel - Re: [PATCH v8 05/15] x86/msr-index: Define MSR_IA32_CORE

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Message-ID: <20190425194714.GA58719@gmail.com>
Date:   Thu, 25 Apr 2019 21:47:14 +0200
From:   Ingo Molnar <mingo@...nel.org>
To:     Fenghua Yu <fenghua.yu@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        H Peter Anvin <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Ashok Raj <ashok.raj@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ravi V Shankar <ravi.v.shankar@...el.com>,
        Xiaoyao Li <xiaoyao.li@...el.com>,
        Christopherson Sean J <sean.j.christopherson@...el.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        Michael Chan <michael.chan@...adcom.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        x86 <x86@...nel.org>, kvm@...r.kernel.org,
        netdev@...r.kernel.org, linux-wireless@...r.kernel.org
Subject: Re: [PATCH v8 05/15] x86/msr-index: Define MSR_IA32_CORE_CAPABILITY
 and split lock detection bit


* Fenghua Yu <fenghua.yu@...el.com> wrote:

> On Thu, Apr 25, 2019 at 07:45:11AM +0200, Ingo Molnar wrote:
> > 
> > * Fenghua Yu <fenghua.yu@...el.com> wrote:
> > 
> > > A new MSR_IA32_CORE_CAPABILITY (0xcf) is defined. Each bit in the MSR
> > > enumerates a model specific feature. Currently bit 5 enumerates split
> > > lock detection. When bit 5 is 1, split lock detection is supported.
> > > When the bit is 0, split lock detection is not supported.
> > > 
> > > Please check the latest Intel 64 and IA-32 Architectures Software
> > > Developer's Manual for more detailed information on the MSR and the
> > > split lock detection bit.
> > > 
> > > Signed-off-by: Fenghua Yu <fenghua.yu@...el.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 ca5bc0eacb95..f65ef6f783d2 100644
> > > --- a/arch/x86/include/asm/msr-index.h
> > > +++ b/arch/x86/include/asm/msr-index.h
> > > @@ -59,6 +59,9 @@
> > >  #define MSR_PLATFORM_INFO_CPUID_FAULT_BIT	31
> > >  #define MSR_PLATFORM_INFO_CPUID_FAULT		BIT_ULL(MSR_PLATFORM_INFO_CPUID_FAULT_BIT)
> > >  
> > > +#define MSR_IA32_CORE_CAPABILITY	0x000000cf
> > > +#define CORE_CAP_SPLIT_LOCK_DETECT	BIT(5)     /* Detect split lock */
> > 
> > Please don't put comments into definitions.
> 
> I'll remove the comment and change definitions of the MSR and the split lock
> detection bit as following:
> 
> +#define MSR_IA32_CORE_CAPABILITY                       0x000000cf
> +#define MSR_IA32_CORE_CAPABILITY_SPLIT_LOCK_DETECT_BIT 5
> +#define MSR_IA32_CORE_CAPABILITY_SPLIT_LOCK_DETECT     BIT(MSR_IA32_CORE_CAPABILITY_SPLIT_LOCK_DETECT_BIT)
> 
> Are these right changes?

I suspect it could be shortened to CORE_CAP as you (partly) did it 
originally.

Thanks,

	Ingo