linux-kernel - Re: [GIT PULL] x86/cpu changes for v3.9

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Message-ID: <5123C28F.50405@zytor.com>
Date:	Tue, 19 Feb 2013 10:21:03 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
CC:	Ingo Molnar <mingo@...nel.org>,
	Konrad Rzeszutek Wilk <konrad@...nel.org>,
	Borislav Petkov <bp@...en8.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [GIT PULL] x86/cpu changes for v3.9

On 02/19/2013 10:19 AM, Boris Ostrovsky wrote:
> On 02/19/2013 12:57 PM, Konrad Rzeszutek Wilk wrote:
>> On Tue, Feb 19, 2013 at 06:47:58PM +0100, Borislav Petkov wrote:
>>> On Tue, Feb 19, 2013 at 09:38:31AM -0800, H. Peter Anvin wrote:
>>>> My fault... I was tracking the fix and lost track of the thread.
>>>>
>>>> The problem is that the fix is necessary but not sufficient, as it
>>>> introduces an undesirable host-guest dependency.  In order to allow
>>>> neerw guests to work on older hosts we also should use the
>>>> {rd,wr}msr_safe() functions to manipulate this MSR, with a comment
>>>> as to why.
>>>>
>>>> Boris, could you prepare such a patch, please?
>>> I don't think Boris O. is at AMD anymore. Want me to add that to my fix
>>> for kvm or prep a separate patch?
>> CC-ing Boris.
>
> BorisP's patch is what I should have done. Can you take it?
>

As I stated:

 >>>> The problem is that the fix is necessary but not sufficient, as it
 >>>> introduces an undesirable host-guest dependency.  In order to allow
 >>>> neerw guests to work on older hosts we also should use the
 >>>> {rd,wr}msr_safe() functions to manipulate this MSR, with a comment
 >>>> as to why.

	-hpa

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

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