linux-kernel - Re: [PATCH v2 2/5] x86/cpuid: refactor setup_clear_cpu_cap()/clear_cpu

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Message-ID: <Y1LGkTXCksqAYLHD@zn.tnic>
Date:   Fri, 21 Oct 2022 18:19:29 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Maxim Levitsky <mlevitsk@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>,
        Josh Poimboeuf <jpoimboe@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Tony Luck <tony.luck@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        "David S. Miller" <davem@...emloft.net>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "Chang S. Bae" <chang.seok.bae@...el.com>,
        Jane Malalane <jane.malalane@...rix.com>,
        Kees Cook <keescook@...omium.org>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Jiri Olsa <jolsa@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        linux-perf-users@...r.kernel.org,
        "open list:CRYPTO API" <linux-crypto@...r.kernel.org>
Subject: Re: [PATCH v2 2/5] x86/cpuid: refactor
 setup_clear_cpu_cap()/clear_cpu_cap()

On Mon, Jul 18, 2022 at 05:11:20PM +0300, Maxim Levitsky wrote:
> Currently setup_clear_cpu_cap passes NULL 'struct cpuinfo_x86*'
> to clear_cpu_cap to indicate that capability should be cleared from boot_cpu_data.
> 
> Later that is used in clear_feature to do recursive call to
> clear_cpu_cap together with clearing the feature bit from 'cpu_caps_cleared'
> 
> Remove that code and just call the do_clear_cpu_cap on boot_cpu_data directly
> from the setup_clear_cpu_cap.
> 
> The only functional change this introduces is that now calling clear_cpu_cap
> explicitly on boot_cpu_data also sets the bits in cpu_caps_cleared,
> which is the only thing that makes sense anyway.
> 
> All callers of both functions were checked for this and fixed.

Change looks ok. What I can't grok is this sentence: what was checked
and fixed where?

What does need fixing and why?

Thx.

-- 
Regards/Gruss,
    Boris.

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