[fedora-virt] close VM display => qemu-kvm goes to 100%

I was running updates on my new fedora 17 KVM, so I figured it would take a while and I closed virt-manager. The qemu-kvm process for the virtual machine had been running at maybe 5 or 10 percent of the cpu, as soon as I closed the windows, it went to 100%. When I opened virt-manager again and opened the VM, the cpu dropped back down to 5 or 10%. It did choose to install the VM with spice as the display. Is this behavior somehow related to spice? Or maybe the display drive inside the VM (that is one of the thing which is probably getting an update now).