[libvirt-users] [libvirt] xml config nested

[Daniel P. Berrange]

NB, in future please don't CC all possible mailing lists at once.
Just pick the most appropriate mailing list for your question. I've
dropped libvirt-list & libvirt-announce from the CC, since this is
a question most suited for libvirt-users.

On Thu, Jan 05, 2017 at 11:44:29AM +0800, 放牛班的春天 wrote:
> How to configure libvirt, so qemu-kvm support nested virtualization, virtual machine installed operating system is windows_7_ultimate_sp1_x64_dvd_618537.iso, configure libvirt xml file is as follows:
> 
>  <cpu mode='custom' match='exact'>
>     <model fallback='allow'>core2duo</model>
>     <feature policy='require' name='vmx'/>
>   </cpu>
> 
> 
> or
> 
>   <cpu mode='host-model'>
>     <model fallback='allow'/>
>   </cpu>
> 
> or
>  <cpu mode='host-passthrough'>
>     <topology sockets='2' cores='2' threads='2'/>
>   </cpu>

Yes, that's the key guest configuration step - exposing the 'vmx' feature
to the guest.

In addition to that though, you need to make sure the kvm-intel kernel
module in your host has the "nested=1" parameter set.

eg in /etc/modprobe.d/kvm.conf you want

 options kvm_intel nested=1

If loaded correctly you should see

# cat /sys/module/kvm_intel/parameters/nested 
Y

if it says "N", then nested VMX will be disabled.

Regards,
Daniel
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