Re: Nested SVM and migration

Zachary Amsden
2010-02-22T17:00:16Z

On 02/22/2010 06:44 AM, Avi Kivity wrote:
> On 02/22/2010 06:42 PM, Zachary Amsden wrote:
>> On 02/21/2010 02:24 AM, Avi Kivity wrote:
>>> On 02/21/2010 02:10 PM, Joerg Roedel wrote:
>>>
>>>> It is doable but I still think its
>>>> complicated to get this right. The simplest approach would be to
>>>> disallow migration when the vcpu is running in guest mode.
>>>
>>> Agree, though I dislike the need to introduce a "force vmexit" ioctl.
>>>
>>
>> How can this possibly work for guests which never exit SVM? They can
>> never be migrated.
>
> The force vmexit would generate an INTR #vmexit even if the INTR
> intercept was disabled and even if no INTR is pending. However this
> was shot down since there was no equivalent vmx exit reason that we
> can except the guest to reasonably handle.

While true, my point is more precisely - how can this possibly work for
guests which MUST never exit SVM? As in, the hypervisor is broken or
deliberately disabled from taking exits, and in fact, may no longer even
exist in memory?

Zach