Can KVM CPU assignment count differ from physical hosts CPU count?

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http://serverfault.com – I have read this question. I knew already that I could for example, have a quad core machine with four guests each having two vCPUs. As they don't all be require 100% CPU usage all the time, the scheduler would handle this for me. My question is about how this relates to a fail-over or migration situation; If host1 has two dual-core CPUs, and I assign guest1 four vCPUs (so it accessed all four physical cores), what will happen if I try and migrate it to host2 which only has one dual-core CPU? Can qemu-kvm emulate more vCPUs than there are physical? Or would I have to shut down the virtual m (HowTos)