22.7. Managing the Time on Virtual Machines
Virtual machines cannot access a real hardware clock and a virtual clock is not stable enough as the stability is dependent on the host systems work load. For this reason, para-virtualized clocks should be provided by the virtualization application in use. On Red Hat Enterprise Linux with KVM the default clock source is
kvm-clock. See the KVM guest timing management chapter of the Virtualization Host Configuration and Guest Installation Guide.