[libvirt-users] Nested KVM: L0 guest produces kernel BUG on wakeup from managed save (while a nested VM is running)

[Florian Haas]

On Fri, Feb 9, 2018 at 11:48 AM, Kashyap Chamarthy <kchamart at redhat.com> wrote:
> On Thu, Feb 08, 2018 at 06:44:43PM +0100, Florian Haas wrote:
>> On Thu, Feb 8, 2018 at 1:07 PM, David Hildenbrand <david at redhat.com> wrote:
>> > We should certainly document what I have summaries here properly at a
>> > central palce!
>>
>> Please review the three edits I've submitted to the wiki:
>> https://www.linux-kvm.org/page/Special:Contributions/Fghaas
>>
>> Feel free to ruthlessly edit/roll back anything that is inaccurate.
>> Thanks!
>
> I've made some minor edits to clarify a bunch of bits, and a link to the
> Kernel doc about Intel nVMX.  (Hope that looks fine.)

I'm sure they it does, but just so you know I currently don't see any
edits from you on the Nested Guests page. Are you sure you
saved/published your changes?

> You wrote: "L2...which does no further virtualization".  Not quite true
> — "under right circumstances" (read: sufficiently huge machine with tons
> of RAM), L2 _can_ in turn L3. :-)

Insert "normally" between "which" and "does", then. :)

> Last time I checked (this morning), Rich W.M. Jones had 4 levels of
> nesting tested with the 'supernested' program[1] he wrote.  (Related
> aside: This program is packaged it as part of 2016 QEMU Advent
> Calendar[2] -- if you want to play around on a powerful test machine
> with tons of free memory.)
>
> [1] http://git.annexia.org/?p=supernested.git;a=blob;f=README
> [2] http://www.qemu-advent-calendar.org/2016/#day-13

Interesting, thanks for the pointer!

Cheers,
Florian