You either have to reboot or <code>rmmod/modprobe</code> the corresponding module if no VM is running
== VM configuration ==
The following is largely untested, therefore this is more an instruction on how to figure out what the correct setting is.
First try to start any VM and execute the following to see whether virtualization is available '''in the guest''':
<source lang='bash'>
grep vmx /proc/cpuinfo
</source>
If there is support, the output should be something like this:
<pre>
flags : [...] vmx [...]
</pre>
If it does not get enabled automatically by libvirt as soon as the hypervisor supports nested virtualization (it should, though), you have to change to XML description of the VM. To that end, use <code>virsh edit</code> on the node after having it defined it and replace the lines:
<source lang='xml'>
<cpu mode='host-model'>
<model fallback='allow'/>
</cpu>
</source>
with
<source lang='xml'>
<cpu mode='host-model'>
<model fallback='allow'/>
<feature policy='require' name='vmx'/>
</cpu>
</source>
[[Category:stoney cloud]][[Category:Installation]]