Hi,

I have some questions about the CPU-Capabilities for Virtualization especially for Nested Virtualization like the Turtles Project.
I am trying to create a Nested Environment by following the instruction of: http://kashyapc.wordpress.com/2012/01/18/nested-virtualization-with-kvm-and-amd/

The bare-metal system is a Dell Server with following CPU-Flags (virsh capabilities)

<cpu>
<arch>x86_64</arch>
<model>Opteron_G4</model>
<vendor>AMD</vendor>
<topology sockets='1' cores='8' threads='2'/>
<feature name='nodeid_msr'/>
<feature name='wdt'/>
<feature name='skinit'/>
<feature name='ibs'/>
<feature name='osvw'/>
<feature name='cr8legacy'/>
<feature name='extapic'/>
<feature name='cmp_legacy'/>
<feature name='fxsr_opt'/>
<feature name='mmxext'/>
<feature name='osxsave'/>
<feature name='monitor'/>
<feature name='ht'/>
<feature name='vme'/>
</cpu>

After adding this Flags to the XML of my first VM, the following XML-Attributes are written to the file, after reopening it.


<cpu mode='custom' match='exact'>
<model fallback='allow'>Opteron_G4</model>
<vendor>AMD</vendor>
<feature policy='require' name='nodeid_msr'/>
<feature policy='require' name='wdt'/>
<feature policy='require' name='skinit'/>
<feature policy='require' name='ibs'/>
<feature policy='require' name='osvw'/>
<feature policy='require' name='cr8legacy'/>
<feature policy='require' name='extapic'/>
<feature policy='require' name='cmp_legacy'/>
<feature policy='require' name='fxsr_opt'/>
<feature policy='require' name='mmxext'/>
<feature policy='require' name='osxsave'/>
<feature policy='require' name='monitor'/>
<feature policy='require' name='ht'/>
<feature policy='require' name='vme'/>
</cpu>


The problem is, that after adding this attributes to the XML, I am not able to load the kvm-modules in the VM. So I´m not able to install the Nested VM in the VM.
But when I´m not adding the attributes to the XML and keep the XML-File of the VM unmodified, I´m able to load the KVM modules in the VM and I can install the Nested Guest.

So my first question is, what difference it makes for the Nested Virtualization, when I´m not adding the Attributes and keep the XML-Files unmodified?

And my second qestion is, what essential difference is between the qemu version 0.14 which was used by the instruction of Kashyap Chamarthy and the version 1.0 related to Nested Virtualization?

I hope you understand my problem because it is quite confusing for me and I´m not sure that I´m using the right techniqe for my Nested Environment!!

Best Regards,

Mike