Bug#883938: Same problem with KVM

[Grischa Zengel]

I had the same problem with my VMs under Proxmox/KVM.

After changing CPU structure from "2 socket 1 CPU" to "1 socket 2 CPU" the 
problem was gone.
Only enabling/disabling NUMA didn't work.

So I think it's a problem with aktivating second prozessor.