Nested VT-x/AMD-V not working

[sand7000]

I installed 6.0 via the script:

VirtualBox-6.0.0-127566-Linux_amd64.run

today to take advantage of the new nested virtualization option, I saw no errors during the install. I have the new version of the extensions installed as well and I rebooted after installation. The option "Enable Nested VT-x/AMD-V" is greyed out in the graphical interface. I was able to turn it on by running:

VBoxManage modifyvm ubuntu-xen --nested-hw-virt on

but it doesn't seem to do anything. I expected to see vmx or svm in /proc/cpuinfo on the guest but I do not. I am still unable to start an Xen HVM guest inside the ubuntu guest (PV worked on 5.x and still works now). Am I missing a dependency or something?

[andyp73]

You haven't given much to go on to help diagnose this issue. Firstly, to quote section 10.35 of the user manual:

Oracle VM VirtualBox supports nested virtualization on host systems that run AMD CPUs.

If you don't have an AMD CPU don't expect it to work! If you do have an AMD CPU then you probably need to make sure it it the right type. To say much more we will need to see the VBox.log file from the guest in question (zipped of course).

-Andy.

[sand7000]

Hmmm, I did miss that. 'Enable Nested VT-x/AMD-V' a pretty misleading name for the feature since VT-x is only on Intel processors.

I will try on another machine tonight and see if I have better luck.

Thanks!

[socratis]

@sand7000
There is a specific thread that I've created just for this purpose: Nested virtualization: Success stories (and failures). Please consider posting there, but ONLY if you try this on an AMD CPU. As it's noted in the thread, all Intel CPU posts will be deleted/split.