Re: [Qemu-discuss] Windows-10 virtualization and nested virtualization

[Jeff Forbes]

When I use "-cpu host,+VMX,-hypervisor", Hyper-V gives this error when trying to start a VM:

Virtual Machine could not be started because the hypervisor is not running.

So with the latest kernel and qemu-kvm, the hypervisor flag is needed.

On Mon, 2016-04-04 at 17:35 -0400, Bandan Das wrote:

> Jeff Forbes <address@hidden> writes:
>
> > We have a Windows-10 application which uses a virtual as part of the
> > process. I am trying to get the application to work in a virtual
> > environment, which of course will require nested 	virtualization.
> >
> > Using a libvirt xml description for a RHEL virtual where nested 
> > 	virtualization works, I installed windows-10, Hyper-v and the
> > application software under the latest updates of Fedora 22.
> > Windows-10 works great; however, VMBus device required for Hyper-V to
> > work would not start and was flagged in the Device Manager. Trying to
> > start a virtual resulted in the error that a component required by
> > Hyper-V failed to start.
> >
> > I then ported the VM to VMWare Workstation 12 and in this environment t
> > he VMBus device starts and nested virtuals start as expected. These
> > results indicated that the VM was working correctly and the problem was
> > likely with the QEMU-KVM hypervisor.
> >
> > Reading recent messages on the KVM and QEMU mail lists indicated that
> > there were many KVM updates made to the 4.6.0-rc1 kernel, so I
> > download, compiled and installed this kernel. I also cloned the latest
> > version of qemu. When I run my Windows-10 VM in this environment with
> > the latest updates. the VMBus device starts and there are not warnings
> > in the Device Manager; however, the nested VMs do not start and the
> > same error about a component required by Hyper-V failed to start.
> >
> > Do I need to turn something on to get this to work or is the Hyper-V
> > support still under development?
>
>
> I am not sure if anyone has been successful with running Hyper-V nested.
> The first obstacle I remember is Hyper-V refusing to run when it finds
> the "hypervisor" flag in guest cpu. If you are past that step,  maybe
> the vmbus dependency is something else.
>
> > Please advise.
> >
> >
> > Best,
> >
> > Jeff--
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to address@hidden
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html