"Enable nested virtualization" button is bugged

[IL]

I downloaded and installed last VirtualBox version for Windows: 6.1.34 r150636 (Qt5.6.2). I ran a VM. Then I wanted to turn on nested virtualization in CPU's options, but the button was disabled (see screenshot attached). I have AMD Ryzen 5600x CPU and SMV is enabled in UEFI options.

I managed to figure out the problem spending some time on this: I used the console tool. This command works correctly: VBoxManage.exe modifyvm "test" --nested-hw-virt on The checkbox becomes being checked after that and nested virt is turned on. If I uncheck the checkbox again, it becomes inactive again.

Please, fix the checkbox. I didn't notice the issue with the other checkboxes.

[IL]

checkbox is inactive

[IL]

And, of course, the VM was turned off when I wanted to change the settings.

[fth0]

This VBoxManage command is independent on the capabilities of the current CPU, but the checkbox in the VirtualBox Manager is not. A few years ago I learned that this is deliberate behavior.

Please provide a (zipped) VBox.log file of a run of a VM showing this behavior. The VM doesn't need an installed OS for that. ;)

[IL]

Recorded one with the checkbox enabled.
From the log I found this:
00:00:02.438968 SVM - AMD Secure Virtual Machine extensions = 0 (0)
But this is wrong, I've SVM enabled, otherwise, my VM wouldn't start.

Also found this:
00:00:02.023891 CPUM: WARNING! Can't turn on nested VT-x/AMD-V when NEM is used''
What is NEM?

Is there anything anymore interesting?

[fth0]

Your Windows host OS is running under the Hyper-V hypervisor, which means that VirtualBox itself has no access to hardware virtualization (VT-x/AMD-V/SVM) and can only use the slower Native Execution Mode (NEM).

[IL]

But this is not true, my host OS is native. Why it shows like that?

[IL]

Even the corresponded Windows features are disabled.

[IL]

I reviewed my machine in HWInfo and found the reason: HVCI (Hypervisor-protected code integrity) was enabled.
After turning it off (In Win10: Core Isolation -> Memory Protection option) the checkbox works as intended.
What VBox GUI could do is to handle this case somehow or add a notification to the checkbox tooltip.
Thanks, you can close the issue.

[balti]

Turn off the NX Mode, and turn on the SVM Mode in the BIOS. Then turn off the Memory integrity of the Core isolation in the Windows Defender.