Host XP, Guest Win7 x64, CPU has VTx

[AntiMatter]

Hi,

Could you please tell me if the following scenario is possible:

1- Using VirtualBox 3.04 on Win XP host (regular 32 bits XP) - this is the work machine.
2- The CPU is Intel Core2 which has VTx support and VTx is enable in the Bios
3- Create a new VM, Guest OS is Windows 7, 64 bits
4- Then transfer the VDI file to an Ubuntu 9.04 x64 bits host (home machine) and run it using VirtualBox 3.04 Linux

In summary, can a guest OS 64 bits be safely created from a 32 bits host? The reason of this convoluted way of doing is because the guest OS Windows 7 can only be activated at work and I don't have an Ubuntu machine at work.

Thanks in advance for any help.

[Sasquatch]

It can only be done if the CPU is 64 bit. You can't run a 64 bit guest with VT-x turned on if the processor isn't 64 bit. Makes sense, don't you think? Host environment doesn't matter, since 2.2.x or before, can't remember exactly, both 32 bit and 64 bit Hosts can create 64 bit Guests, as long as the hardware support is there. See the manual and VirtualBox FAQ for that.

[AntiMatter]

Thanks for the link to the FAQ. Sorry I forgot to mention that the CPU is also 64 bits.
According to the FAQ, I am afraid that my scenario won't be successful. The host OS must also be 64 bits and the VM must be created from Virtualbox 64 bits.

Excerpted from Virtuabox FAQ:

VirtualBox also supports 64-bit guest operating systems, under the following conditions:
1. You need a 64-bit processor with hardware virtualization support (see User Manual chapter 1.2, Software vs. hardware virtualization (VT-x and AMD-V), page 10) and a 64-bit host operating system.
2. You must run a 64-bit version of VirtualBox on that OS (Windows Vista, Linux or OpenSolaris). This can then run both 32-bit and 64-bit VMs; a 32-bit VirtualBox can only run 32-bit VMs, regardless of the hardware.
3. You must enable hardware virtualization through your BIOS; software virtualization is not supported for 64-bit VMs.

[baf]

That is outdated info. From the manual for 3.0.4

Starting with Version 2.1, you can even run 64-bit guests on a 32-bit host operating
system, so long as you have sufficient hardware.
In particular, 64-bit guests are supported under the following conditions:
1. You need a 64-bit processor with hardware virtualization support (see chapter
1.2, Software vs. hardware virtualization (VT-x and AMD-V), page 11).
2. You must enable hardware virtualization for the particular VM for which you
want 64-bit support; software virtualization is not supported for 64-bit VMs.
3. If you want to use 64-bit guest support on a 32-bit host operating system, you
must also select a 64-bit operating system for the particular VM. Since supporting
64 bits on 32-bit hosts incurs additional overhead, VirtualBox only enables this
support upon explicit request.
On 64-bit hosts, 64-bit guest support is always enabled, so you can simply install
a 64-bit operating system in the guest.
Warning: On any host, you should enable the I/O APIC for virtual machines
that you intend to use in 64-bit mode. This is especially true for 64-bit Windows
VMs. See chapter 3.7.1.2, “Advanced” tab, page 46. In addition, for
64-bit Windows guests, you should make sure that the VM uses the Intel networking
device, since there is no 64-bit driver support for the AMD PCNet
card; see chapter 6.1, Virtual networking hardware, page 82.

[Sasquatch]

Yeah, with new releases, we often fail to include the changes in the FAQ. Will update it.

[AntiMatter]

Thanks baf for the correction. I confirm that it is possible to run a Windows 7 x64 guest using a WinXP host 32 bits. The CPU is 64 bits and VTx compatible.

I cannot tell about the stability and performance of the Windows 7 x64 guest. I have just played around with it for less than 1 hour. All I need is to to have the VM approved and activated by my network admin. After that I take it home and run it on Ubuntu 9.04 x64 host (it's a VM I use for training).