kvm/x86/running-nested-guests.rst

4 Running nested guests with KVM
8 can be KVM-based or a different hypervisor).  The straightforward
9 example is a KVM guest that in turn runs on a KVM guest (the rest of
20               |          KVM (/dev/kvm)            |
24       |                    KVM (/dev/kvm)                    |
31 - L0 – level-0; the bare metal host, running KVM
34   hypervisor", as it itself is capable of running KVM.
56 There are several scenarios where nested KVM can be useful, to name a
61   Provider, using nested KVM lets you rent a large enough "guest
79 From Linux kernel v4.20 onwards, the ``nested`` KVM parameter is enabled
84 nesting, set the ``nested`` KVM module parameter to ``Y`` or ``1``.  To
89    the KVM modules::
100 3. For the nested KVM configuration to persist across reboots, place the
107 4. Unload and re-load the KVM Intel module::
112 5. Verify if the ``nested`` parameter for KVM is enabled::
159 nested guest with accelerated KVM.
179 3. Now the KVM module can be loaded in the L1 (guest hypervisor)::
184 Live migration with nested KVM
225 - Ensure you are actually running KVM on KVM.  Sometimes people do not
226   have KVM enabled for their guest hypervisor (L1), which results in
228   they think they're running nested KVM.  Thus confusing "nested Virt"
229   (which could also mean, QEMU on KVM) with "nested KVM" (KVM on KVM).