linux-kernel - Re: [PATCH 1/2] x86: fix keeping track of AMD C1E

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Message-ID: <4C408298.8060004@zytor.com>
Date:	Fri, 16 Jul 2010 09:02:32 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Borislav Petkov <borislav.petkov@....com>
CC:	Michal Schmidt <mschmidt@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"Herrmann3, Andreas" <Andreas.Herrmann3@....com>,
	Shaohua Li <shaohua.li@...el.com>,
	Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH 1/2] x86: fix keeping track of AMD C1E

On 07/16/2010 12:22 AM, Borislav Petkov wrote:
>>
>> No, the difference between using a separate variable and the CPU feature 
>> bit is that CPU feature bit is ANDed across all CPUs, whereas this 
>> variable is set if it is set on *any* CPU.
> 
> ... and that's ok because the MSR bits get set on all cores after BIOS
> turns on C1E. Let me verify this though.
> 

Is there any reason for the OR behavior?  Otherwise, it's just plain
wrong...

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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