Enable Nested VT-x/AMD-V: Enables nested virtualization, with passthrough of hardware virtualization functions to the guest VM.
With virtual machines running modern server OSes, Oracle VM VirtualBox also supports CPU hot-plugging.
First you need to make sure virtualization is enabled in the BIOS, restart your computer and press the access key before the operating system boots.
Depending on the BIOS used or the computer you have, it can change the access key, sometimes it's F2, sometimes F9 or F8 etc.
Read your motherboard manual for details or try to read quickly, the small text that appears on the monitor at startup should read "Press F2 to enter BIOS".
Be very careful to modify the BIOS because it determines the functioning of the computer.
When you are done, boot your Linux machine normally and open the terminal.
First we identify the virtual machines present.
$ vboxmanage list vms
After we give the command to modify the parameter.
$ vboxmanage modifyvm "NameVirtualOS" --nested-hw-virt on
Now the parameter is enabled.
The computer you are using must support this virtualization technology, Nested VT-x is a way of using your hardware in a more direct way, having more performance on the virtual machine.
Ciao,
Mattia
Links:
Official Guide
https://www.virtualbox.org/manual/ch03.html#settings-acceleration
StackOverflow post
https://stackoverflow.com/questions/54251855/virtualbox-enable-nested-vtx-amd-v-greyed-out
