Enable 64 bits virtualbox inside another 64-bit virtualbox

[tpthao37]

I installed a virtualbox (called vb1) on host mac os with guest Ubuntu.
In the guest Ubuntu, I installed another virtualbox (called vb2), and want to install win 7 64 bits on this vb2.
However, it shows only 32 bits os only. So, how to turn it to 64 bits?

It is unlike vb1. To turn on vb1 to 64 bits, we need:
- Boot BIOS (host), enable virtualization
- Disable Hyper-V.

Thank you

[mpack]

Not possible. VirtualBox 64bits support uses hardware accelerated virtualization, which is not available to the guest (VBox uses it on the host).

[socratis]

It is unlike vb1. To turn on vb1 to 64 bits, we need:
- Boot BIOS (host), enable virtualization
- Disable Hyper-V.

Did you go into the BIOS and make sure that virtualization is enabled? Would you mind posting a VBox.log for vb1? Right-click on the VM, select Show log, save it, ZIP it and attach it here.

[tpthao37]

Did you go into the BIOS and make sure that virtualization is enabled?

Yes, I did. I must do so because I installed ubuntu 64 bits (successed).
The problem is turning virtualization of vb2 in order to install win 7 64 bits inside vb2.
We cannot go to virtual BIOS (vb1).

I attached the log of vb1 here.

[socratis]

Yes, I did. I must do so because I installed ubuntu 64 bits (successed).

No you did not. Macs do not have a BIOS. You mentioned Mac OS and BIOS in the same description and I wanted to make sure that you were actually on Apple hardware. Again, you could not have gone into a Mac's BIOS to enable virtualization. BIOS doesn't exist for a Mac.

As mpack said, you cannot have a 64-bit VM inside a 64-bit VM. The 64-bit VM does not support or understand hardware acceleration. What you can do it 32-bit VMs, which if they work they're going to be too slow. That is called nested virtualization (a VM inside a VM) and it is not supported.

Having said that, you're lucky that Ubuntu (vb1) is running at all.

00:00:01.005460 Host RAM: 16384MB total, 4862MB available
00:00:01.088631   RamSize           <integer> = 0x00000002c0000000 (11 811 160 064, 11 GB)

You do not have 11 GB available on your host to give to your guest.