linux-kernel - Re: [PATCH 1/3] x86/cpu: Process all CPUID dependencies after identifying CPU info

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Message-ID: <Y7ajQY8w+qpOSI4p@zn.tnic>
Date:   Thu, 5 Jan 2023 11:15:29 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Subject: Re: [PATCH 1/3] x86/cpu: Process all CPUID dependencies after
 identifying CPU info

On Wed, Jan 04, 2023 at 11:18:31PM +0000, Sean Christopherson wrote:
> Yes, this is purely to drop the explicit X86_FEATURE_MSR_IA32_FEAT_CTL checks.

Yeah, we can do that as it is simple enough.

Btw, we already resolve deps - or forced features but whatever, it is similar -
in apply_forced_caps(). And we call it right before we "sync" the feature bit
arrays with boot_cpu_data's in identify_cpu().

So I'm thinking this all, including your change, should be carved out in a
separate function and all the CPU flags massaging should be concentrated there.

And that should happen last in identify_cpu() - that ppin_init() thing sets and
clears cpu caps too. ;-\

But I can do that ontop, so how do you wanna merge this?

I take it or I review it and you take it or... ?

-- 
Regards/Gruss,
    Boris.

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