[root@kvm-hypervisor ~]# cat /sys/module/kvm_intel/parameters/nested
N
[root@kvm-hypervisor ~]# vi /etc/modprobe.d/kvm-nested.conf
options kvm-intel nested=1
options kvm-intel enable_shadow_vmcs=1
options kvm-intel enable_apicv=1
options kvm-intel ept=1
[root@kvm-hypervisor ~]# reboot
[root@kvm-hypervisor ~]# cat /sys/module/kvm_intel/parameters/nested
Y
Reference
How to enable Nested Virtualization in KVM on CentOS 7 / RHEL 7
https://www.linuxtechi.com/enable-nested-virtualization-kvm-centos-7-rhel-7/
RHEV-M with nested VM for OSP
https://iranzo.github.io/blog/2015/07/17/rhev-m-with-nested-vm-for-osp/
vdsm-hook-nestedvt, vdsm-hook-macspoof
After it boots, egrep 'svm|vmx' /proc/pcuinfo should show the flags there.
Nested Virtualization in KVM(RHV)