KubeVirt can be configured with kubevirt.spec.configuration.defaultRuntimeClass to specify the name of a default PriorityClass to be used when nothing is set on vm.spec.template.spec.priorityClassName on the individual VM.

Since we are currently not setting any value for defaultRuntimeClass, virt-launcher pods are scheduled by default with the same priority class used by other generic pods.

So virt-launcher pods are not more protected or privileged than other generic pods (that can typically be easily restarted on other nodes). 

CNV v4.19

100%

1. $ oc get -n openshift-cnv kubevirt kubevirt-kubevirt-hyperconverged -o json | jq  '.spec.configuration.defaultRuntimeClass'
2.
3.

$ oc get -n openshift-cnv kubevirt kubevirt-kubevirt-hyperconverged -o json | jq  '.spec.configuration.defaultRuntimeClass'
null

HCO is creating a priorityclass (with a priority than is higher than in the class used by default for pods) to be used for VM pods.
HCO is configuring it on spec.configuration.defaultRuntimeClass on the CR for KubeVirt.

Any pod requiring a preempting priority class can actually preempt (kill!) VMs:
see: https://kubernetes.io/docs/concepts/scheduling-eviction/pod-priority-preemption/