Going crazy at VT-x

N

Ndvn

New Member
Oct 23, 2017
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Hello,

I've recently installed Proxmox 5 on VirtualBox running on an i7 6820HQ laptop. It ran flawlessly. I ran both 32bit and 64bit VM (not CT!) on that proxmox.

I needed to change various things, so I created a new virtualbox proxmox instance, and ever since I can't run ANY proxmox VM's anymore - "No Accelerator Found".

I tried reinstalling Proxmox 4 times (2 times on the same virtualbox host, and twice in a *new* virtualbox instances). I made sure VT-x and Nested Paging are all ticked and enabled. I even tried Paravirtualization of KVM, Hyper-V and Legacy. Not sure its relevant, but also enabled/disabled PAE/NX.

Nothing. All VM's, in any of my proxmox virtualbox hosts, are not running, "No Acccelerator Found".

I didn't update my computer bios, I verified that VT-d and VT-x are both enabled in the BIOS.

I'm lost :(

Any ideas?
 
Hi,

virtual box do not support nested virtualization.
So what you try is not possible.
 
wolfgang said:
Hi,

virtual box do not support nested virtualization.
So what you try is not possible.
Click to expand...

Ok, now I doubt myself. I honestly believed that the first proxmox installation I had was running a VM - but after your reply, I honestly think that I might have "de"marked the "KVM" under options of that specific proxmox internal vm...

I saw that you're a staff member, and I wouldn't wish to imply that I doubt your answer by no means :) But is this a thing? I've been googling that matter since yesterday, and even though I saw plenty of posts about it that matter, I just didn't realize that virtualbox, a hypervisor of over 10 years, isn't keeping up to date with its competitors.


However, if "Nested virtualization" isn't possible, what are those *virtualbox* features that I mentioned? VT-x enabled, nested paging? Don't they mean that virtualbox gives its VMs "virtual access" to the physical computer VT-x features? I know this is a "virtualbox" question, and I'm sorry to be developing it here in Proxmox - but I'm just so surprised at this.

If you guys don't mind, and you know, I'd like to read your comment on why "Enable VT-x" is an option - yet, its not enough to allow nested vir. ?
 
Heh, you were right with the quotation marks at "working" - thats why I answered the first reply with "I started doubting myself".

Read my initial post, I have removed my first proxmox instance - hence I can't verify why it worked. Thats why I started thinking whether I've removed the KVM option.. and thats since I got surprised that they dont support it.
 
@ Ndvn

You can run a VM in two different modes

Emulated virtualization
Proxmox: kvm checkbox unchecked
Virtualbox: vt-x and nested paging unchecked

Hardware virtualization
Proxmox: kvm checkbox checked
Virtualbox: vt-x and nested paging checked

Emulated virtualization is very slow and not what you ask for.
 
wolfgang said:
@ Ndvn

You can run a VM in two different modes

Emulated virtualization
Proxmox: kvm checkbox unchecked
Virtualbox: vt-x and nested paging unchecked

Hardware virtualization
Proxmox: kvm checkbox checked
Virtualbox: vt-x and nested paging checked

Emulated virtualization is very slow and not what you ask for.
Click to expand...

@wolfgang - Thank you, but I kinda lost the bearing here :( Your first reply you said this is impossible.. However, what you suggested now (Checking VT-X and Nested Paging *with* KVM checkbox in proxmox) - is exactly what I did in my 2nd and 3rd attempts, which made me open the original thread.

I said that the 1st attempt worked, but since I deleted the proxmox instance, and your initial reply made me doubt that I did it properly, I started to think I didn't notice something.

Can anyone verify that their implementation of proxmox in virtualbox, with vt-x and nested paging, allows vm's in proxmox to run with KVM box checked? meaning, they dont recieve the "no accelerator found" error ?
 
if you have access to windows 10 machine or windows server 2012 R1 machine
with Hyper-V you can have nested setup there as well. and it is already included.

here is how to do that in Hyper-V

#1. create a VM. the only strict requirement for the VM is no dynamic memory. you have to define the amount of ram you think you will need. !! no dynamic ram!!

#1.a set MAC spoofing "on" for the VM. this is needed so nested VMs could communicate with the network

#2. open PowerShell in admin mode.
PS>> you can save the code below into ps1 file and run it that way or just copy/past the code into powershell window. I prefer to use the UI, PS ISE interface.
make sure you set the name of your VM into variable (the very first line)
for Proxmox you will need a Gen-1 VM it usually will not run in Gen-2 VM. never could make it work for Gen-2.



a one-liner is
Code: 
Set-VMProcessor -VMName WS2016 -ComputerName Nano -  ExposeVirtualizationExtensions $true

or more elaborate script with messages like this.

Code: 
$VMNAME = "[YourVMName]"

WRITE-HOST $("ExposeVirtualizationExtensions (Before) :")(Get-VMProcessor -VMName $VMNAME).ExposeVirtualizationExtensions

if((Get-VM -Name $VMNAME).VirtualMachineSubType -eq 'Generation1'){ Write-Host "Generation1 VM. No Secure boot."}
else {Set-VMFirmware -VMName $VMNAME -EnableSecureBoot Off } ## Disable secure boot for Gen 2 VM

## enable nested virtualization
Set-VMProcessor -VMName $VMNAME  -ExposeVirtualizationExtensions $true
WRITE-HOST $("ExposeVirtualizationExtensions (After) :") (Get-VMProcessor -VMName $VMNAME).ExposeVirtualizationExtensions
 
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