Nested virtualization - running Hyper-V on Windows 10 guest under KVM with Linux Mint 18 as host

Question

I'm trying to do nested virtualization in different hypervisor environments. Virtualbox does not support nested virtualization "out-of-the-box" according to my experience. VMWare Workstation Player 12 does, and I'm able to use Hyper-V on Windows 10 host. But under KVM (installed from the repository with virt-manager GUI) I'm not able to achieve the same goal. I get the following error from the Windows 10 guest: "Hyper-V cannot be installed. Virtualization support is disabled in firmware". I want to run Windows XP as guest OS in Windows 10 (Hyper-V) under Linux Mint 18 host. :-)

Any suggestions on how I can solve this problem ?

• user576053: Nested virtualization is a pretty steep topic, you might want to ask on specialized forums for people who do this kind of stuff.
• toyman61: OK. I was adviced to ask on this forum, but it might be the wrong one. Do you know which forum I should use then ?

Answer 1

You need the use the kvm_intel nested=1 parameter when booting the kernel of your host OS (Mint Linux) to enable nested virtualization with KVM on an Intel-based system.

As Mint is based on the Debian distribution, the instructions here will be useful to setup the system.

• toyman61: I have already checked that the kvm_intel nested=1 is present. (And as I said earlier: VMWare Workstation Player 12 supports Hyper-V on Windows 10 guest... :-)
• Haxiel: @toyman61 : Right, but I'd guess that the abstraction between operating systems will vary with the Hypervisor under use. Could you verify the requirements according to this? It would also be good for comparison if you check the requirements on the VMWare setup and the KVM setup.
• toyman61: When I run "systeminfo.exe" on my Windows 10 host under kvm virtualization I get the following information: Hyper-V Requirements: A hypervisor has been detected. Features required for Hyper-V will not be displayed. It seems to me that Windows 10 has detected a hypervisor (KVM ?) and that's the reason why Hyper-V could not be started. (Maybe the CPU-flag '-hypervisor' has something to do with this ?)
• Haxiel: When creating the Guest OS using Hyper-V Manager, have you set Use Dynamic Memory to off? This seems to be required for a Nested Hyper-V host. In addition, try running the PowerShell script mentioned here.

Answer 2

I have had a try at this a while back, with limited success.

Full discussion can be found here: https://lists.nongnu.org/archive/html/qemu-discuss/2015-10/msg00039.html

The error you are getting is because Hyper-V wants MSR 0x3a return "5". This signifies that VT extensions are present and enabled in the BIOS. With a very small hack in vmx.c file, you can get Hyper-V to install: https://bugzilla.kernel.org/show_bug.cgi?id=106621

However, you cannot actually start Virtual Machines in the nested hypervisor.