From mboxrd@z Thu Jan  1 00:00:00 1970
From: Zachary Amsden <zamsden@redhat.com>
Subject: Re: Nested SVM and migration
Date: Wed, 24 Feb 2010 10:21:44 -1000
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Cc: Joerg Roedel <joro@8bytes.org>, Avi Kivity <avi@redhat.com>,
	kvm <kvm@vger.kernel.org>
To: Joerg Roedel <joerg.roedel@amd.com>
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On 02/24/2010 05:23 AM, Joerg Roedel wrote:
> On Sun, Feb 21, 2010 at 02:09:15PM +0100, Joerg Roedel wrote:
>    
>> On Sun, Feb 21, 2010 at 02:54:01PM +0200, Avi Kivity wrote:
>>      
>>> So, if some other cpu (or the guest itself, with appropriate
>>> permissions) modifies the msr permission bitmap, svm will not notice
>>> this?  svm loads the bitmap during entry?
>>>        
>> Yes.
>>      
> Talked again with a few people about it and the architectural answer is
> a bit different. The right answer to that is:
>
> The cpu is allowed to load the msr permission map to internal state, but
> not required to do it by the architecture. The result of changing the
> msr permission map of a running vmcb is undefined.
>
> So we are fine with the way nested svm does it. And we don't need to
> care about that situation at all and just migrate whats in guest memory.
>    

Awesome!  Thanks for checking it out.