Kubevirt wants to (for-now) do "disk-only" snapshots of a running VM. While they are aware that it's equivalend to a power failure, the virt stack should ensure that external processes such as the vTPM serialize their state properly for the snapshot.

Libvirt and qemu will need to evaluate how the vTPM state is persisted and what to do to ensure the recovery from "power failure" induced by a revert from a "disk only" snapshot.

See also:

https://groups.google.com/a/redhat.com/g/virt-devel/c/iA-1CSi1IFE