linux-kernel - Re: [PATCH v4 06/12] x86/mtrr: replace vendor tests in MTRR code

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Message-ID: <20230327071454.GBZCFCbqzj+NTx0GkL@fat_crate.local>
Date:   Mon, 27 Mar 2023 09:14:54 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Juergen Gross <jgross@...e.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH v4 06/12] x86/mtrr: replace vendor tests in MTRR code

On Mon, Mar 27, 2023 at 07:43:58AM +0200, Juergen Gross wrote:
> The is_cpu() checks are either in functions reachable only with mtrr_if being
> set, or are testing for INTEL, which is replaced by the test of mtrr_if being
> &generic_mtrr_ops as written in the commit message.

I went through all call sites... it seems like what you're saying should
work. I guess this mtrr_if check was added as a precaution in 2002 as
part of a cleanup:

commit 8fbdcb188e31ac901e216b466b97e90e8b057daa
Author: Dave Jones <davej@...e.de>
Date:   Wed Aug 14 21:14:22 2002 -0700

    [PATCH] Modular x86 MTRR driver.
    
    This patch from Pat Mochel cleans up the hell that was mtrr.c
    into something a lot more modular and easy to understand, by
    doing the implementation-per-file as has been done to various
    other things by Pat and myself over the last months.
    
    It's functionally identical from a kernel internal point of view,
    and a userspace point of view, and is basically just a very large
    code clean up.

So let's see what catches fire...

Thx.

-- 
Regards/Gruss,
    Boris.

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