Enabling the VT-x inside a virtual machine

问题

I work in Ubuntu from Oracle Virtual Machine which is installed on top of Windows.

I have activated the VT-x feature in the host BIOS. After this I created a new virtual machine with VT-x and EPT enabled.

Now I run

$ egrep '(vmx|svm)' /proc/cpuinfo

from the guest to check if the vmx feature is enabled and the answer is 0, i.e. not enabled.

How can I enable this feature on the guest VM?

回答1:

You can't enable VT-x inside Virtualbox. There's a ticket for it that hasn't been fixed yet

[Edit by klaus 2018-05-06:]

This feature is being worked on for a while. Once the implementation is complete and tested it will be available to all users.

[feature-request] Nested Virtualization: VT-in-VT

It's possible to run nested VMs with Hyper-V and VMWare ESX or ESXi though

Run Hyper-V in a Virtual Machine with Nested Virtualization
How to enable VT-X on VM
Is it possible to use VMX CPU instructions inside VM?
How to enable VT-x inside a Virtual Machine inside a Virtual Machine
Is it possible to setup a virtual machine inside another virtual machine
How to run VMWare ESX or ESXi in a virtual machine?
Nested virtualization - is it possible?

However it does need EPT to run. Make sure your host CPU has EPT support. Without EPT you can only run 32-bit VMs using binary translation

Intel VT-x or AMD-V is required for running “Nested Virtualization” which supports nested 32-bit VMs

Intel EPT or AMD RVI is required for running nested 64-bit VMs.

https://www.virtuallyghetto.com/2012/08/how-to-enable-nested-esxi-other.html

Some hypervisors do refuse to run if it found out that it's running inside a virtual machine or in a virtual machine some levels deep. That said, it's possible to run arbitrarily deep nested virtual machines using binary translation or an emulator like Bochs or qemu