Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 26 Oct 2022 12:37:53 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     Juergen Gross <jgross@suse.com>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v4 07/16] x86/mtrr: split generic_set_all()
Message-ID: <Y1kOAUDYW7HpRvfl@zn.tnic>
References: <20221004081023.32402-1-jgross@suse.com>
 <20221004081023.32402-8-jgross@suse.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <20221004081023.32402-8-jgross@suse.com>
Precedence: bulk

On Tue, Oct 04, 2022 at 10:10:14AM +0200, Juergen Gross wrote:
> Split generic_set_all() into multiple parts, while moving the main
> function body into cacheinfo.c.
> 
> Prepare the support of PAT without needing MTRR support by
> moving the main function body of generic_set_all() into cacheinfo.c
> while renaming it to cache_cpu_init(). The MTRR specific parts are
> moved into a dedicated small function called by cache_cpu_init() in
> order to make cache_cpu_init() as MTRR agnostic as possible.
> 
> The setting of smp_changes_mask is merged into the (new) function
> mtrr_generic_set_state() used to call set_mtrr_state(). It was
> probably split in ancient times, as atomic operations while running
> uncached might be quite expensive, but OTOH only systems with a
> broken BIOS should ever require to set any bit in smp_changes_mask,
> so just hurting those devices with a penalty of a few microseconds
> during boot shouldn't be a real issue.

This still needs addressing

"So the commit message should not say what you're doing - that should
be visible from the diff itself. It should talk more about the *why*
you're doing it."

-- 
Regards/Gruss,
    Boris.

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