linux-kernel - Re: [PATCH] x86/MCE: Get microcode revision from cpu_info instead of boot_cpu

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Message-ID: <56E0BDAC-816A-4F72-A4C6-2747F4A8AA67@amazon.de>
Date:   Fri, 1 Jun 2018 12:32:02 +0000
From:   "Sironi, Filippo" <sironi@...zon.de>
To:     Borislav Petkov <bp@...en8.de>
CC:     "tony.luck@...el.com" <tony.luck@...el.com>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86/MCE: Get microcode revision from cpu_info instead of
 boot_cpu_data

> On 1. Jun 2018, at 14:19, Borislav Petkov <bp@...en8.de> wrote:
> 
> On Fri, Jun 01, 2018 at 01:30:26PM +0200, Filippo Sironi wrote:
>> Commit fa94d0c6e0f3 ("x86/MCE: Save microcode revision in machine check
>> records") extended MCE entries to report the microcode revision taken
>> from boot_cpu_data. Unfortunately, boot_cpu_data isn't updated on late
>> microcode loading,
> 
> Actually, I'd prefer if we fixed *that* instead by adding:
> 
> 	/* Update boot_cpu_data's revision too, if we're on the BSP: */
> 	if (c->cpu_index == boot_cpu_data.cpu_index)
> 		boot_cpu_data.microcode = <new rev>;
> 
> to the end of ->apply_microcode() functions so that boot_cpu_data has
> the correct revision too, in case something else queries it.
> 
> Thx.
> 
> -- 
> Regards/Gruss,
>    Boris.
> 
> ECO tip #101: Trim your mails when you reply.
> --

I've that patch in my tree already, I can post it.
I'm still curious on why you'd prefer to use boot_cpu_data for all
CPUs instead of using cpu_data(m->extcpu) though.

Regards,
Filippo


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