Enable Nested VT-X/AMD-V not working

Discussions related to using VirtualBox on Windows hosts.
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rohret
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Joined: 26. Jan 2023, 20:03

Enable Nested VT-X/AMD-V not working

Post by rohret »

I am using Ubuntu-22-04 on virtualbox (windows host). I ran into issues when I tried to install docker desktop. The solution is to enable KVM virtualization support. However, I enabled Nested VT-X/AMD-V in Virtualbox. I checked the box but I still get "KVM acceleration can NOT be used" when I run the command "sudo /usr/sbin/kvm-ok" in Ubuntu. Why does it not work when I activate Nested VT-X/AMD-V?
mpack
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Re: Enable Nested VT-X/AMD-V not working

Post by mpack »

How can we tell when you don't provide a log?

Consulting my crystal ball.... one obvious reason might be that if the host is using Hyper-v then VirtualBox has no access to VT-x itself, and therefore can't pass it to a VM either. Also, nested VT-x requires certain processor features, so it would be nice to know what your processor is.
rohret
Posts: 2
Joined: 26. Jan 2023, 20:03

Re: Enable Nested VT-X/AMD-V not working

Post by rohret »

I am not sure what logs you want to see. I did disable Hyper-v and my processor allows nested VT-x. To clarify my question, when I run the command "sudo kvm-ok" on ubuntu I get "Your CPU does not support KVM extension". The problem is that I think I have done everything that is nessecary to do. I have enabled Nested VT-X/AMD-V in virtualbox and disabled Hyper-v, Virtual Machine Platform and Windows Hypervisor Platform on my windows host. And checked that my processor allow nested VT-x.... Why does it not support KVM extensions...
scottgus1
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Re: Enable Nested VT-X/AMD-V not working

Post by scottgus1 »

On the Windows host level, Start the VM from full normal shutdown, not save-state. Run until you see the problem happen, then shut down the VM from within the VM's OS if possible. If not possible, close the Virtualbox window for the VM with the Power Off option set.

Right-click the VM in the main Virtualbox window's VM list, choose Show in Explorer/Finder/File Manager. In the "Logs" subfolder, zip the VM's "vbox.log", and post the zip file, using the forum's Upload Attachment tab. (Configure your host OS to show all extensions so you can find the "vbox.log", not "vbox.log.1", etc.)
sonicbuster
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Joined: 7. Mar 2024, 15:02

Re: Enable Nested VT-X/AMD-V not working

Post by sonicbuster »

I got this message trying to run a Linux OS on WSL using nested virtualization:

PS C:\WINDOWS\system32> wsl --install Ubuntu
Ubuntu is already installed.
Launching Ubuntu...
Installing, this may take a few minutes...
WslRegisterDistribution failed with error: 0x80370102
Please enable the Virtual Machine Platform Windows feature and ensure virtualization is enabled in the BIOS.

I have the Nested VT-x/AMD-V checked. I also have PAE/NX enabled. I also ran the command line to set these values. I have attached a log file. I have a Win11 host and a Win11 guest, both running build 22631. I have the Virtual Machine Platform installed and I do not have Hyper-V installed.
Attachments
Hamilton_PC-2024-03-07-08-27-50.log
(104.68 KiB) Downloaded 5 times
fth0
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Re: Enable Nested VT-X/AMD-V not working

Post by fth0 »

First of all, VirtualBox 7.0 doesn't support Hyper-V as a nested hypervisor.

The Windows Virtual Machine Platform feature is the Hyper-V runtime component and needed by WSL2.

The Windows Hyper-V feature is just the Hyper-V VM management component used when creating your own VMs.
sonicbuster
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Joined: 7. Mar 2024, 15:02

Re: Enable Nested VT-X/AMD-V not working

Post by sonicbuster »

Ok, understood. Let me ask a different question - with a Win11 VM, can I get the Linux Subsystem working so I can get Linux running in WSL2?
fth0
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Re: Enable Nested VT-X/AMD-V not working

Post by fth0 »

I think that I implicitly answered your question already (if not, please rephrase your question). To reiterate:

WSL2 needs Hyper-V, and VirtualBox doesn't support Hyper-V als a nested hypervisor. In consequence, you cannot run WSL2 inside a VirtualBox 7.0 Windows 11 VM.
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