linux-kernel - Re: [PATCH] x86/cpu: remove redundant cpu_detect_cache

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Message-ID: <20200117184720.GB31472@zn.tnic>
Date:   Fri, 17 Jan 2020 19:47:20 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Tony W Wang-oc <TonyWWang-oc@...oxin.com>
Cc:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, linux-kernel@...r.kernel.org,
        DavidWang@...oxin.com, CooperYan@...oxin.com,
        QiyuanWang@...oxin.com, HerryYang@...oxin.com
Subject: Re: [PATCH] x86/cpu: remove redundant cpu_detect_cache_sizes

On Wed, Jan 15, 2020 at 04:00:57PM +0800, Tony W Wang-oc wrote:
> Before call cpu_detect_cache_sizes get l2size from CPUID.80000006,
> these CPUs have called init_intel_cacheinfo get l2size/l3size from
> CPUID.4.

Questions:

* Does CPUID(4) give the same result as CPUID(80000006) on those CPUs?

* cpu_detect_cache_sizes() sets c->x86_tlbsize while
init_intel_cacheinfo() would set it only when it calls the former
function - cpu_detect_cache_sizes() - at the end:

        if (!l2)
                cpu_detect_cache_sizes(c);

Does that happen on those CPUs?

-- 
Regards/Gruss,
    Boris.

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