linux-kernel - Re: [PATCH v2 2/6] x86/cpu: Remove "nosep"

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Message-ID: <202202071358.2DA81D84B@keescook>
Date:   Mon, 7 Feb 2022 13:58:48 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Borislav Petkov <bp@...en8.de>
Cc:     X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/6] x86/cpu: Remove "nosep"

On Thu, Jan 27, 2022 at 12:56:22PM +0100, Borislav Petkov wrote:
> From: Borislav Petkov <bp@...e.de>
> 
> That chicken bit was added by
> 
>   4f88651125e2 ("[PATCH] i386: allow disabling X86_FEATURE_SEP at boot")
> 
> but measuring int80 vsyscall performance on 32-bit doesn't matter
> anymore.
> 
> If still needed, one can boot with
> 
>   clearcpuid=sep
> 
> to disable that feature for testing.
> 
> Signed-off-by: Borislav Petkov <bp@...e.de>

Reviewed-by: Kees Cook <keescook@...omium.org>

-- 
Kees Cook