Re: [libvirt] Support for kvm=off cpu option

On 08/11/2014 05:54 PM, Alex Williamson wrote: > As of QEMU 2.1 we now have a new -cpu option, kvm=on|off which controls > whether we expose KVM as the hypervisor via the MSR hypervisor nodes. > The default is on. The off state is meant to hide kvm from standard > detection routines. This allows us to disable paravirtualization > detection in the guest and can be used to bypass hypervisor checks in > certain guest drivers[1]. > > How would we like to enable this in libvirt? One option would be a > processor feature, ex: > > <feature policy='disable' name='kvm'/> > > But since this doesn't map to a cpuid feature, I don't know if that > would be acceptable. > > Another option might be to a domain feature, similar to some of the > other hyper-v related flags. > > <domain type='kvm'> > <features> > <kvm> > <kvm state='off'> > </kvm> > <hyperv> > <relaxed state='on'> > ... > </hyperv> > </features> > ... > </domain> > > Any other suggestions? Preference? Thanks, IMO the latter suggestion makes the most sense.

However <kvm state='off'/> could cause confusion, sounds like it turns off kvm acceleration. Maybe <signature state=on|off>, or hv_signature, something along those lines.