= Enabling nested virtualization in KVM
[[enabling-nested-virtualization-in-kvm]]

Nested virtualization allows you to run a virtual machine (VM) inside
another VM while still using hardware acceleration from the host.

== Checking if nested virtualization is supported

For Intel processors, check the `/sys/module/kvm_intel/parameters/nested` file. +
For AMD processors, check the `/sys/module/kvm_amd/parameters/nested` file. +
If you see `1` or `Y`,nested virtualization is supported; if you see `0` or `N`, nested virtualization is not supported.

For example:
....
$ cat /sys/module/kvm_intel/parameters/nested
Y
....

== Enabling nested virtualization

To enable nested virtualization for Intel processors:

. Shut down all running VMs and unload the `kvm_probe` module:
+
----                                
# modprobe -r kvm_intel
----
. Activate the nesting feature:
+
----
# modprobe kvm_intel nested=1
----
. Nested virtualization is enabled until the host is rebooted. To enable it permanently, add the following line to the `/etc/modprobe.d/kvm.conf` file:
+
----
options kvm_intel nested=1
----

To enable nested virtualization for AMD processors:

. Shut down all running VMs and unload the `kvm_amd` module:
+
----                                
# modprobe -r kvm_amd
----
. Activate the nesting feature:
+
----                    
# modprobe kvm_amd nested=1
----    
. Nested virtualization is enabled until the host is rebooted. To enable it permanently, add the following line to the `/etc/modprobe.d/kvm.conf` file:                        
+
----                                
options kvm_amd nested=1
----