linux-kernel - Re: [PATCH 1/8] x86, microcode, intel: forbid some incorrect metadata

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Date:	Mon, 6 Oct 2014 07:15:36 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Henrique de Moraes Holschuh <hmh@....eng.br>
Cc:	linux-kernel@...r.kernel.org, H Peter Anvin <hpa@...or.com>
Subject: Re: [PATCH 1/8] x86, microcode, intel: forbid some incorrect metadata

On Sun, Oct 05, 2014 at 06:49:08PM -0300, Henrique de Moraes Holschuh wrote:
> How about this:
> 
> 	/*
> 	 * 0 is not a valid microcode revision as it is used to detect the
> 	 * absence of any sucessful microcode update since reset /
> 	 * power-on, see MSR 0x8b (IA32_BIOS_SIGN_ID):
> 	 *
> 	 * "It is required that this register field be pre-loaded with zero
> 	 * prior to executing the CPUID, function 1. If the field remains
> 	 * equal to zero, then there is no microcode update loaded. Another
> 	 * non-zero value will be the signature."
> 	 */
> 

Yep.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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