linux-kernel - Re: [PATCH v3] x86: clear incorrectly forced X86_FEATURE_LAHF

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Date:	Thu, 13 Aug 2009 20:24:42 -0300
From:	Kevin Winchester <kjwinchester@...il.com>
To:	Borislav Petkov <borislav.petkov@....com>
CC:	Mikael Pettersson <mikpe@...uu.se>,
	Borislav Petkov <petkovbb@...glemail.com>,
	Ingo Molnar <mingo@...e.hu>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] x86: clear incorrectly forced X86_FEATURE_LAHF_LM
 flag

Borislav Petkov wrote:
> Hi Kevin,
> 
> On Wed, Aug 12, 2009 at 08:02:14PM -0300, Kevin Winchester wrote:
>> So that feature is definitely set.
> 
> thanks for testing. As a reply to that follow two patches for you to
> test. The one is adding some more msr functionality and the second is
> based on your original one which should in addition turn off the cpuid
> bit. Please apply, compile, reboot and run the small app again to verify
> that ECX[0] is now off.
> 
> Let me know how it goes.
> 

Yes, those patches seem to fix everything:

$ ./a.out  
0x8000_0001_ecx = 0x00000000

I just noticed that my original patch has been pulled into Linus' tree,
so you will likely want to rebase your patches on top of that.

Thank you again,

-- 
Kevin Winchester

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