WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-users

Re: [Xen-users] Prohibit to run Xen inside guest VM?

On Tue, Dec 15, 2009 at 12:59 PM, Jun Koi <junkoi2004@xxxxxxxxx> wrote:
>>>> Technically the only way you could run nested Xen is by using a HVM
>>>> domU. Even then you'd get close to dead snail performance, and you can
>>>> only have PV guests.
>>>
>>> Why we can only have PV guests, but not HVM?
>>> I know that currently nested hypervisor is not good in performance,
>>> but that might very well change in the future.
>>
>> HVM requires a special CPU feature (AMD-V or intel-VT) that can only
>> be used by the hypervisor, and not by domU. Which is why you can't
>> have nested HVM guest or (in the case of Windows) nested Hyper-V
>> guests.
>
> Yes, but most machines now already have virtualization capable CPU. I
> dont think the ISP uses very old machine that is without VT-x or
> AMD-V.

The OS that's running inside HVM domU will NOT be able to utilize
intel-vt or amd-v.
That's why nested HVM domU is not possible.

>
> I have some more questions:

As Rob said, you'd probably get better answer for those questions on
another list.

-- 
Fajar

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users