For windows newer than 1803, it would have a high CPU on host (20%) even when the guest CPU is idle. It needs the following Hyper-V Enlightenments. https://github.com/qemu/qemu/blob/master/docs/hyperv.txt <hyperv> <synic state='on'/> <stimer state='on'/> </hyperv> The end xml: <hyperv> <relaxed state='on'/> <vapic state='on'/> <spinlocks state='on' retries='8191'/> <synic state='on'/> <stimer state='on'/> </hyperv> These should be the default setting when create the vm from vm-manager. Keep here for reference. <clock offset='localtime'> <timer name='rtc' tickpolicy='catchup'/> <timer name='pit' tickpolicy='delay'/> <timer name='hpet' present='no'/> <timer name='hypervclock' present='yes'/> </clock> Reference: https://bugzilla.