Nested guests are KVM guests run in a KVM guest. As of Feb 2018 this feature is considered working but experimental, and some limitations apply. When describing nested guests, we will use the following terminology: "L0" – the bare metal host, running KVM "L1" – a VM running on L0; also called the "guest hypervisor" — as it itself is capable of running KVM "L2" – a VM running on L1, also called the