Re: [Qemu-devel] is it possible to run KVM module inside a qemu VM

[Alexander Graf]

On 29.04.2012, at 12:48, Nadav Har'El wrote:

> On Sun, Apr 29, 2012, Steven wrote about "is it possible to run KVM module 
> inside a qemu VM":
>> Hi,
>> I know there exists nested KVM in the kernel tree such that a KVM
>> hypervisor can run inside a guest.
>> Now I am wondering if it is possible to load the kvm module in a qemu
>> VM (-no-kvm). So I started a qemu VM using the following command
> 
> No, I believe this is NOT possible.
> 
> KVM, as the top (L0) hypervisor, implements the VMX instructions for the
> L1 guest using the hosts' VMX. Qemu, on the other hand, does not have VMX
> emulation at all.
> 
> Note that before you set out to add VMX instructions emulation, you need
> to also consider the option of emulating SVM (AMD's virtualization
> extensions) instead of VMX - even on Intel hosts. I believe (though I
> didn't consider this too carefully) this will be easier to implement,
> as in many respects, SVM is simpler than VMX.

SVM is already implemented in TCG, though the support may not be 100% 
compatible to real hardware ;).


Alex