linux-kernel - Re: [PATCH] x86/microcode: Be more verbose, especially about loading errors

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Message-ID: <20231206203158.GEZXDaPslvxtOS/gze@fat_crate.local>
Date:   Wed, 6 Dec 2023 21:31:58 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Jann Horn <jannh@...gle.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/microcode: Be more verbose, especially about loading
 errors

On Wed, Dec 06, 2023 at 09:23:48PM +0100, Jann Horn wrote:
> Well, yes, except that if no microcode blob is loaded, you're not
> gonna have the errata fixes and/or security mitigations that you might
> expect to have.

We say that too:

microcode: Current revision: 0x000000f0
microcode: Updated early from: 0x000000be

That second line would be missing.

And updated microcode != microcode version for all the mitigations is
even available.

Therefore, the mitigation fixes all report that too. Look for
"[Mm]icrocode" in the mitigation strings in arch/x86/kernel/cpu/bugs.c.

-- 
Regards/Gruss,
    Boris.

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