linux-kernel - Re: [PATCH 18/23] x86/srso: Remove redundant X86_FEATURE_ENTRY

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Message-ID: <20230902091021.GBZPL7/UhPLiOmf2Fg@fat_crate.local>
Date:   Sat, 2 Sep 2023 11:10:21 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Josh Poimboeuf <jpoimboe@...nel.org>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Babu Moger <babu.moger@....com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>, David.Kaplan@....com,
        Andrew Cooper <andrew.cooper3@...rix.com>,
        Nikolay Borisov <nik.borisov@...e.com>,
        gregkh@...uxfoundation.org, Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 18/23] x86/srso: Remove redundant X86_FEATURE_ENTRY_IBPB
 check

On Fri, Aug 25, 2023 at 12:01:49AM -0700, Josh Poimboeuf wrote:
> The X86_FEATURE_ENTRY_IBPB check is redundant here due to the above
> RETBLEED_MITIGATION_IBPB check.  RETBLEED_MITIGATION_IBPB already
> implies X86_FEATURE_ENTRY_IBPB.  So if we got here and 'has_microcode'
> is true, it means X86_FEATURE_ENTRY_IBPB is not set.
> 
> Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
> ---
>  arch/x86/kernel/cpu/bugs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

I still don't like this one:

https://lore.kernel.org/r/20230825070936.GEZOhTsPiTLhY1i9xH@fat_crate.local

-- 
Regards/Gruss,
    Boris.

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