[vbox-dev] Nested virtualization problem

[Geoff Nordli]

>-----Original Message-----
>From: Ruben Van den Bossche
>Sent: Monday, October 11, 2010 1:59 AM
>
>  Dear VBox developers,
>
>We are currently extending work performed by Olivier Berghmans regarding
>nested virtualization (running a virtual machine inside another virtual
machine).
>Because none of us has experience with hypervisor development, we would
very
>much appreciate it if you could confirm or correct one of our assumptions.
>
>In our experiments, nesting DBT based hypervisors appears impossible when
using
>a base hypervisor based on DBT. Using first generation hardware support as
the
>base hypervisor results in partial success depending on the hypervisor used
(
>VMWare, Xen, KVM, Virtualbox ). When we move the base hypervisor to a
>machine with second generation hardware support most problems disappear.
>
>We think the most likely reason for the problems with DBT or first gen.
>hardware support as base hypervisor technique are the results of shadow
paging,
>and more specifically the nested shadow paging which occurs when nesting
DBT
>on DBT or first gen HWS. Perhaps some functionality is not replicated
exactly as
>one would expect on physical hardware?  Maybe some shortcuts result in
corrupt
>memory if they are used in nested hypervisors? If you could confirm these
>assumptions or perhaps even give some greater insight in these problems, we
>would be extremely grateful.
>
>Kind Regards,
>
>Sam Verboven and Ruben Van den Bossche
>PhD Students
>University of Antwerp

Being able to do nested virtualization would be an amazing feature in
VirtualBox!!!!

We are in the training field, and if we could run hypervisor related
training like VMWare and Hyper-V on vbox that would be an outrageously
amazing feature.

In addition some software like the new Windows Phone 7 software emulator
uses virtualization.   

Geoff