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

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Message-ID: <20231206210421.GFZXDh1UQ7L8K/toOM@fat_crate.local>
Date:   Wed, 6 Dec 2023 22:04:21 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     "Sironi, Filippo" <sironi@...zon.de>
Cc:     Tony Luck <tony.luck@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
        "hpa@...or.com" <hpa@...or.com>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>
Subject: Re: [PATCH] x86/MCE: Get microcode revision from cpu_data instead of
 boot_cpu_data

On Fri, Dec 01, 2023 at 07:56:59PM +0000, Sironi, Filippo wrote:
> Boris, I just took a quick look and I might be missing something. If cores
> fail to load the microcode or timeout, we taint the kernel, print an error
> message, and then bubble up an error to userspace via:
> 
> load_late_stop_cpus
> load_late_locked
> reload_store
> 
> Right?

Yap.

> We would take servers that fail out of production;

And I'd like to hear about such issues. We added this failure checking
only recently because something might go wrong and we want to warn. But
it all updates fine here so kinda hard to test.

My expectation is that if microcode fails loading on a subset of
machines, the machine would more or less freeze. Depending, ofc, on what
the microcode is updating...

> however, for others it might be interesting to have the correct
> information. The patch - with a reworked commit message - might still
> be useful to a few.

https://lore.kernel.org/r/20231118193248.1296798-3-yazen.ghannam@amd.com

:)

-- 
Regards/Gruss,
    Boris.

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