Proxmox nested virtualization, Windows + Virtualbox

[Pietro95]

I recently installed Proxmox in an AMD EPYC 7302 16-Core Processor server, in addition to normal VMs I need to create a Windows VM that will start VMs with Virtualbox using a software we use to develop PLC software.

This setup worked on a previous Intel Xeon server with ubuntu and KVM/QEMU.

 

I followed the Proxmox guide here:

https://pve.proxmox.com/wiki/Nested_Virtualization

 

My Windows VM seems to correctly recognize virtualization support by displaying it in the task manager or on CPU-Z.

 

My VM configuration:

args: -cpu 'host,+svm,-hypervisor'
bios: ovmf
boot: order=scsi0;ide2;net0
cores: 4
cpu: host
efidisk0: Storage:106/vm-106-disk-1.qcow2,size=128K
ide2: Storage:iso/Windows10_InsiderPreview_Client_x64_en-us_21354.iso,media=cdrom
machine: pc-q35-5.2
memory: 16384
name: PCT3
net0: virtio=0E:C3:3D:3C:E8:79,bridge=vmbr0,firewall=1
numa: 0
ostype: win10
parent: Inizio
sata1: Storage:iso/virtio-win-0.1.185.iso,media=cdrom,size=402812K
scsi0: Storage:106/vm-106-disk-0.qcow2,discard=on,size=200G
scsihw: virtio-scsi-pci
smbios1: uuid=88dc3ecd-ee73-4fe2-b802-6f0cde889e9e
sockets: 1
vmgenid: 7b28e483-aaad-49cb-8170-27d645eae13c

Virtualbox creating a virtual machine manually with Ubuntu gets stuck and doesn't start.

Documenting I seem to read that this is a problem using Windows and AMD CPU, I am currently using Windows 10 Insider Preview build 21354 but the problem remains, I also tested with Windows server .

Can nested virtualization work? is not supported by Windows?

Quote

 

The nested virtualization capability has so far been tested on "AMD's first generation Ryzen/Epyc or newer processors," the announcement indicated.

Microsoft hinted that it'll be possible to use Linux-based virtual machines with nested virtualization, stating that "Linux KVM [kernel-based virtual machine] guest support will be coming in the future."

 

 

 

Thanks in advance for the support

 

[Jarsky]

I've not explicitely tried this setup so it may be something to do with Windows, but I do run nested virtualization on an AMD Ryzen 3950x, with Proxmox on top of UnRAID (both KVM). I can tell you that nested virtualization does work on Ryzen in general, but might be your specific case having Windows in there. Have you experimented with hyper-v or vmware workstation player to see if they give similar results? 

 

Here's Proxmox nested in UnRAID running an Ubuntu Guest

 

 

 

And heres VMware (ESXi) on UnRAID running a Windows Server 2019 Guest

 

 

 

[Pietro95]

10 hours ago, Jarsky said:

I've not explicitely tried this setup so it may be something to do with Windows, but I do run nested virtualization on an AMD Ryzen 3950x, with Proxmox on top of UnRAID (both KVM). I can tell you that nested virtualization does work on Ryzen in general, but might be your specific case having Windows in there. Have you experimented with hyper-v or vmware workstation player to see if they give similar results? 

 

Here's Proxmox nested in UnRAID running an Ubuntu Guest

 

 

 

And heres VMware (ESXi) on UnRAID running a Windows Server 2019 Guest

 

 

 

 

I solved the problem, nested virtualization is buggy with Proxmox linux kernel 5.4, upgrading to 5.11 solved it!