virtualbox.org

I have what looks like a 64-bit install (under Gentoo Linux) on a 64-bit host:
# file /opt/VirtualBox/VirtualBox
/opt/VirtualBox/VirtualBox: setuid ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.4.0, stripped

# uname -m
x86_64

# /opt/VirtualBox/VirtualBox --help
Sun xVM VirtualBox Graphical User Interface 2.0.2

But when I try to boot a x86_64 livecd, the boot process says it needs a 64-bit machine but found only i586. Do I need to do something special to get 64-bit guest to run on a 64-bit host.

OK but read the other posts on this (i) what actual CPU chipset do you have? Some especially the earlier low-end ones do not have VT-x or AMD-V support. (ii) Have you enabled virtualisation support inside your BIOS? If the BIOS turns this off, then just like a guest 64bit OS, this isn't available.

TerryE wrote:OK but read the other posts on this (i) what actual CPU chipset do you have? Some especially the earlier low-end ones do not have VT-x or AMD-V support. (ii) Have you enabled virtualisation support inside your BIOS? If the BIOS turns this off, then just like a guest 64bit OS, this isn't available.

You mean I need VT-x or AMD-V to get 64-bit guest support? That's a bit strange requirement. I have a 64-bit amd64 3800 X2 cpu and no AMD-V. That means I am out of luck with 64-bit guest support. The documentation doesn't seem to mention this fine point about 64-bit guest support.

devsk wrote:You mean I need VT-x or AMD-V to get 64-bit guest support?

Yes

devsk wrote:That's a bit strange requirement.

No

devsk wrote:I have a 64-bit amd64 3800 X2 cpu and no AMD-V. That means I am out of luck with 64-bit guest support. The documentation doesn't seem to mention this fine point about 64-bit guest support.

The Athlon X2 series has AMD-V look in your BIOS. Many OEMs has Deaktivate this CPU Feature by Default.

Next you need to Aktivate ACPI, IOACPI, PAE/NX and AMD-V/VT-x

PS: Some Informations about AMD-V http://en.wikipedia.org/wiki/AMD-V

The Athlon X2 series has AMD-V look in your BIOS. Many OEMs has Deaktivate this CPU Feature by Default.

I know my AMD 3800 X2 doesn't have pacifica extension. But it is 64-bit CPU.

AMD-V is a strange requirement for 64-bit guest support. I see no technical reason for making the 64-bit guest support depend on that extension and proof of that is VMWare. VMWare doesn't have this requirement. It even supports 64-bit guest on a 32-bit host on a CPU which has native 64-bit support.

sorry but VMware does have this requirement, though it does as you say you can virtualize 64-bit OSs from a 32bit one. google vmware pdf amd-v terrye site:forums.virtualbox.org if you want to read some of my earlier discussions on this.

OK. I don't know what that means. I have already mentioned that my CPU doesn't have Pacifica extension.

I can run 64-bit guest on a 32-bit host on my desktop under VMWare. I cannot run 64-bit guest on a 64-bit host on the same desktop under VirtualBox. So, how is the 64-bit guest support same? VMWare doesn't require AMD-V. It CAN use it.

Anyway, I read the requirement list from virtualbox manual again: 3. You must enable hardware virtualization; software virtualization is not supported for 64-bit VMs, which means that no 64-bit guest support if I don't have hardware virtualization. That's a shame because I was waiting for 64-bit guest support for some time now.

If you are saying that you can run a 64bit guest OS under your 32 bit OS on an AMD64 non AMD-V cpu then I am surprised but I won't argue. It is technically possible to employ the same non VT-x software recompilation/patching techniques that both VMare and VBox use for 32bit non-H/W assist CPUs. It's just a lot of work to do this and Sun have decided not to do this for VBox. You'll just have to use VMware.

We can probably mention this thread in the FAQs because there seems to be confusion about this. People mistakenly assume that now virtualbox is a replacement for vmware but the important caveat is the hardware support it needed.

devsk wrote:We can probably mention this thread in the FAQs because there seems to be confusion about this.

Sighh. See the Forum FAQ. This answer is given to the first question already.