linux-kernel - Re: [PATCH 02/49] x86/cpu: Describe hybrid CPUs in cpuinfo

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Message-ID: <20210208191902.GG18227@zn.tnic>
Date:   Mon, 8 Feb 2021 20:19:02 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     "Luck, Tony" <tony.luck@...el.com>
Cc:     "Liang, Kan" <kan.liang@...ux.intel.com>, peterz@...radead.org,
        acme@...nel.org, mingo@...nel.org, linux-kernel@...r.kernel.org,
        tglx@...utronix.de, namhyung@...nel.org, jolsa@...hat.com,
        ak@...ux.intel.com, yao.jin@...ux.intel.com,
        alexander.shishkin@...ux.intel.com, adrian.hunter@...el.com,
        Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...el.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Len Brown <len.brown@...el.com>
Subject: Re: [PATCH 02/49] x86/cpu: Describe hybrid CPUs in cpuinfo_x86

On Mon, Feb 08, 2021 at 11:10:18AM -0800, Luck, Tony wrote:
> > +u32 x86_read_hybrid_type(void)
> > +{
> > +	if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU))
> > +		return cpuid_eax(0x0000001a);
> > +
> > +	return 0;
> > +}
> 
> Machine check logging will want to include this in "struct mce".
> 
> But ok to pick it up with a function like you describe above.

Sure, that looks ok.

We can always lift it up into cpuinfo_x86 later, when it is needed on
the majority of machines but right now it is only a small subset of
machines which have this.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette