[libvirt-users] 100% CPU when using nested virtualization

[Digimer]

Hi all,

  I got a new laptop recently and what worked before no longer works
(Fedora 23 on the laptops in both cases)...

  I'm trying to get nested virtualization to work because I use the VMs
on the laptop to simulate an HA cluster that itself hosts VMs. I don't
care much at all about the performance of the nested VM, it's just there
so that I can work on the cluster's code.

  When I try to provision a VM inside a VM (the host VM is CentOS/RHEL
6.7), the CPU load spikes to such a high degree that my ssh session
times out after a while. The VM appears in libvirtd (as viewed by
virt-manager on another machine), but the VM itself never starts.

  In one case, the VM host remained somewhat functional and killing
kvm/qemu/libvirtd didn't reduce the CPU load.

  The main difference between the setups is that the older laptop had a
Sandy bridge(? Thinkpad W530) and the new laptop is a Broadwell
(Thinkpad P70).

  I've tried to loading vhost_net without much luck. I have, of course,
enabled nesting on the actual hardware:

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

  Any tips on how to debug?

  I'm in quite a pickle with this, so any and all help is much appreciated.

-- 
Digimer
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