Nested virtualization unsupported on WSL2 while the CPU should.

[Baitoven]

Windows Version

Microsoft Windows version 10.0.19045.4291

WSL Version

2.2.2

Are you using WSL 1 or WSL 2?

• [X] WSL 2
• [ ] WSL 1

Kernel Version

5.15.150.1-microsoft-standard-WSL2

Distro Version

Ubuntu 22.04

Other Software

No response

Repro Steps

Windows 10 lastest release with Intel i5 13600KF (on MSI PRO Z790-P WIFI Motherboard) BIOS Updated to latest firmware (7E06vAC1(Beta version)) from 2024-02-27 Intel VT-x and VT-d enabled in BIOS. Virtualization shown as enabled in Windows Task manager. Start WSL from powershell: wsl: nested virtualization is not supported on this computer is displayed.

Expected Behavior

Running sudo kvm-ok inside WSL should return that everything is ok, and it's not.

Actual Behavior

Running sudo kvm-ok inside WSL returns INFO: Your CPU does not support KVM extensions KVM acceleration can NOT be used

Diagnostic Logs

WslLogs-2024-04-15_16-23-34.zip

[github-actions[bot]]

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[elsaco]

@Baitoven your WSL version is older, but on 2.2.2 and kernel 5.15.150.1-microsoft-standard-WSL2 nested virtualization is available:

root@texas:~# kvm-ok
INFO: /dev/kvm exists
KVM acceleration can be used

and from dmesg output:

[    0.394474] KVM: vmx: using Hyper-V Enlightened VMCS
[    0.426816] kvm: already loaded the other module

kvm module info:

root@texas:~# modinfo kvm
name:           kvm
filename:       (builtin)
license:        GPL
file:           arch/x86/kvm/kvm
author:         Qumranet
parm:           tdp_mmu:bool
parm:           mmio_caching:bool
parm:           nx_huge_pages:bool
parm:           nx_huge_pages_recovery_ratio:uint
parm:           flush_on_reuse:bool
parm:           ignore_msrs:bool
parm:           report_ignored_msrs:bool
parm:           min_timer_period_us:uint
parm:           kvmclock_periodic_sync:bool
parm:           tsc_tolerance_ppm:uint
parm:           lapic_timer_advance_ns:int
parm:           vector_hashing:bool
parm:           enable_vmware_backdoor:bool
parm:           force_emulation_prefix:bool
parm:           pi_inject_timer:bint
parm:           mitigate_smt_rsb:bool
parm:           halt_poll_ns:uint
parm:           halt_poll_ns_grow:uint
parm:           halt_poll_ns_grow_start:uint
parm:           halt_poll_ns_shrink:uint

[Baitoven]

@elsaco I don't feel like my issue is version related, tbh. I've tried today to update to WSL v2.2.2, which did not change anything. In my opinion, the issue is hardware related : somehow virtualization features from my CPU are not handled by WSL (but are by Windows, since WSL is working)

[github-actions[bot]]

Diagnostic information

``` .wslconfig found Custom kernel found: 'C:\Users\Adrien\bzImage' Detected appx version: 2.2.2.0 Unexpected format in optional-component.txt: State : DisabledWithPayloadRemoved ```

[Baitoven]

WslLogs-2024-04-16_08-41-55.zip New logs removing previous logs unexpected format

[github-actions[bot]]

Diagnostic information

``` .wslconfig found Custom kernel found: 'C:\Users\Adrien\bzImage' Detected appx version: 2.2.2.0 ```

[zcobol]

@Baitoven you might have to install Hyper-V in order to use nested virtualization inside WSL.

[Baitoven]

@zcobol nested virtualization in WSL2 is supposed to use KVM to run, not HyperV. In my knowledge KVM does not use HyperV and HyperV might even cause some issues. I've already tried enabling HyperV on Windows side, but it does not seem to change anything.

[zcobol]

@Baitoven You're using Win10 and for nested virtualization in WSL you need Win11. See https://learn.microsoft.com/en-us/windows/wsl/wsl-config for details.

nestedVirtualization | boolean* | true | Boolean to turn on or off nested virtualization, enabling other nested VMs to run inside WSL 2. Only available for Windows 11.

[Baitoven]

@zcobol alright. As simple as that. Thanks for that I was indeed missing this piece of information.