How to check if nested KVM is enabled by doing a cat on nested inside sys

Nested KVM is mainly important for testing for example if you wanted to install VMWare or Proxmox Nodes in a virtual environment for testing.  Without nesting, the performance will be extremely slow, since the VMs within the nodes will not be using Virtualization extensions.

I've used wildcard on kvm_ because it could be kvm_intel or kvm_amd depending on whether you have an AMD or Intel CPU.

AMD returns a 0 or 1 (if enabled)

Intel returns a N or Y (if enabled).

cat /sys/module/kvm_*/parameters/nested

Make nested KVM persistent


echo "options kvm-intel nested=Y" > /etc/modprobe.d/kvm-intel.conf
echo "options kvm-amd nested=1" > /etc/modprobe.d/kvm-amd.conf


Apply nested changes right away:

modprobe -r kvm_intel
modprobe kvm_intel nested=1
 

modprobe -r kvm_amd
modprobe kvm_amd nested=1

References:

Enable Nested Virtualization on Virtualbox Howto

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