Re: nested virtualization test report for Xen 4.3-RC1

[konrad wilk <konrad.wilk@oracle.com>]

On 6/27/2013 9:27 AM, Ren, Yongjie wrote:
>> -----Original Message-----
>> From: Pasi Kärkkäinen [mailto:pasik@iki.fi]
>> Sent: Thursday, June 27, 2013 8:47 PM
>> To: George Dunlap
>> Cc: Ren, Yongjie; Xu, Dongxiao; xen-devel; Zhang, Xiantao
>> Subject: Re: [Xen-devel] nested virtualizaiton test report for Xen 4.3-RC1
>>
>> On Thu, Jun 27, 2013 at 12:37:56PM +0100, George Dunlap wrote:
>>> On Fri, May 10, 2013 at 12:07 PM, Ren, Yongjie <yongjie.ren@intel.com>
>> wrote:
>>>> Hi All,
>>>> This the a nested virtualization test report for Xen 4.3-RC1 on Intel
>> hardware. We use Linux 3.9.1 as Dom0.
>>>> a. Virtual EPT and VMCS shadowing features can work fine.
>>>> b. Xen, KVM and VMware can basically work on top of L0 Xen.
>>>> c. 32bit/64bit Linux and Windows are covered as L2 guests.
>>> Sorry I just saw this -- thanks for the nice enumeration.
>>>
>>> Two questions.  First, I don't see the Win7 "XP compatibility mode" on
>>> this list -- that would be L0 Xen, L1 Win7, L2 XP.  This seems like
>>> probably the most likely actual real-world use of nested virt.  Is
>>> that on your radar at all?
>>>
> So far, I didn't test this case.
> That's a good use case. I'll add this case in my next report about nested virt.
>
>>> Secondly, what do you think is the primary use case for Xen-on-Xen (or
>>> KVM-on-Xen, &c)?  Who would want to use it and why?
>>>
> I'm not sure which type of nested virt is more important. But I heard some use cases as following.
>
> 1. public cloud (e.g. Amazon EC2: if they can provide virtual VMX to the VMs, that can be a value-added service.)
>
> 2. QA: Nested virt can make QAs easy to set up the testing env (especially: virt/cloud areas).
> In a Ovirt Workshop, I heard some guys have been testing Ovirt in KVM nested virtualization.
> Some OpenStack guys also told me that they want to test OpenStack in a VM not on physical host.
And also development. I do use that for some of the low-level assembler 
coding - as I can trigger QEMU to dump the CPU state when printing out 
to the debug port. Quite useful when I was poking in suspend/resume logic.

I was quite happy to see Xen 4.3 + Fedora 18 allow me to nicely boot 
under Xen an Xen HVM OS. Didn't try yet to run an HVM guest within the 
HVM context.