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From: Zachary Amsden <zamsden@redhat.com>
To: Joerg Roedel <joerg.roedel@amd.com>
Cc: Joerg Roedel <joro@8bytes.org>, Avi Kivity <avi@redhat.com>,
	kvm <kvm@vger.kernel.org>
Subject: Re: Nested SVM and migration
Date: Wed, 24 Feb 2010 10:21:44 -1000	[thread overview]
Message-ID: <4B858A58.3080507@redhat.com> (raw)
In-Reply-To: <20100224152325.GA3168@amd.com>

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.

  reply	other threads:[~2010-02-24 20:21 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-20 19:14 Nested SVM and migration Zachary Amsden
2010-02-20 20:18 ` Joerg Roedel
2010-02-20 23:26   ` Zachary Amsden
2010-02-21 12:10     ` Joerg Roedel
2010-02-21 12:24       ` Avi Kivity
2010-02-21 12:41         ` Joerg Roedel
2010-02-21 12:54           ` Avi Kivity
2010-02-21 13:09             ` Joerg Roedel
2010-02-21 13:14               ` Avi Kivity
     [not found]                 ` <4B8137E7.4030001@redhat.com>
     [not found]                   ` <20100221144352.GC26465@8bytes.org>
2010-02-22 16:54                     ` Zachary Amsden
     [not found]                     ` <4B814C41.7010105@redhat.com>
     [not found]                       ` <20100221155624.GD26465@8bytes.org>
2010-02-22 16:56                         ` Zachary Amsden
2010-02-22 16:59                           ` Avi Kivity
2010-02-22 16:46               ` Zachary Amsden
2010-02-22 17:07                 ` Joerg Roedel
2010-02-24 15:23               ` Joerg Roedel
2010-02-24 20:21                 ` Zachary Amsden [this message]
2010-02-22 16:42         ` Zachary Amsden
2010-02-22 16:44           ` Avi Kivity
2010-02-22 17:00             ` Zachary Amsden
2010-02-22 17:02               ` Avi Kivity
2010-02-22 17:07                 ` Zachary Amsden
2010-02-22 17:11                   ` Avi Kivity
2010-02-22 17:24                     ` Zachary Amsden
2010-02-22 16:39       ` Zachary Amsden
2010-02-21  7:23   ` Avi Kivity
2010-02-21  7:46     ` Gleb Natapov
2010-02-21  8:12       ` Avi Kivity
2010-02-21 12:18     ` Joerg Roedel

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