VirtualBox

Opened 2 years ago

Last modified 2 years ago

#21008 new defect

"Enable nested virtualization" button is bugged

Reported by: IL Owned by:
Component: GUI Version: VirtualBox 6.1.34
Keywords: Cc:
Guest type: all Host type: Windows

Description

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.

Attachments (3)

checkbox.JPG (27.0 KB ) - added by IL 2 years ago.
checkbox is inactive
Log.zip (31.5 KB ) - added by IL 2 years ago.
features.JPG (80.9 KB ) - added by IL 2 years ago.

Download all attachments as: .zip

Change History (10)

by IL, 2 years ago

Attachment: checkbox.JPG added

checkbox is inactive

comment:1 by IL, 2 years ago

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

comment:2 by fth0, 2 years ago

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 learnt 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. ;)

Version 0, edited 2 years ago by fth0 (next)

by IL, 2 years ago

Attachment: Log.zip added

comment:3 by IL, 2 years ago

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?

comment:4 by fth0, 2 years ago

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).

comment:5 by IL, 2 years ago

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

by IL, 2 years ago

Attachment: features.JPG added

comment:6 by IL, 2 years ago

Even the corresponded Windows features are disabled.

comment:7 by IL, 2 years ago

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.

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