Hardware Intel VT support to guest OSes

[pingda]

Folks,

I have an ESXi server installed on a Intel E5410 platform which have hardware Intel VT capability.

However, I have a guest OS ubuntu which is looking for using kvm (Kernel-based Virtual Machine)

which requires hardware VT support.

I've check feature flags in /proc/cpuinfo seems there's no vmx/smx flags that means KVM is not support

on my ubuntu guest OS.

Is there any my possible mistaken of configuration or any possible way to enable/provide hardware VT to

guest OS on ESXi ?

--Ed

[AWo]

Welcome to the forums!

Have you enabled the VT function in the host BIOS? If not do so and COLD BOOT the system.

If you found this information useful, please consider awarding points for "Correct" or "Helpful" answers/replies. Thanks!!

[admin]

Current VMware products do not virtualize the VT-x or AMD-V extensions.

[oreeh]

And I wonder if virtualizing them would make sense.

I assume that would add quite some overhead.

[RParker · Accepted solution]

I've check feature flags in /proc/cpuinfo seems there's no vmx/smx flags that means KVM is not support on my ubuntu guest OS.

If you check unbuntu configuration and readme you will note that KVM is NOT supported as a Virtual Machine. It's only for native hardware access or bare metal. VT extensions cannot be virtualized, as Oliver mentioned. ESX uses VT extensions from a hardware level to make use of 64-bit guest machines, but you can't pass these VT extensions to a subsidiary VM.

[admin]

And I wonder if virtualizing them would make sense.

I assume that would add quite some overhead.

It is true that nested VMs are always going to be slow, but there are some applications for which performance is not the critical factor.

For example, there are those who would like to run a 64-bit guest in an ESX VM--for training, testing, or demo purposes. On Intel platforms, this would require virtualizing VT-x for the ESX guest.

[RParker]

For example, there are those who would like to run a 64-bit guest in an ESX VM--for training, testing, or demo purposes. On Intel platforms, this would require virtualizing VT-x for the ESX guest.

Sure, we are all aware what VT extensions are for, and utilizing them for VM's is one thing, but applications within the guest, that's what he is talking about. So passing this VT extension from the hardware layer to ESX is already accomplished, but what isn't happening is VT extensions virtualized for Applications within the guest OS, and I am with Oliver on this one, it doesn't make sense to further virtualize them, there are just some things Virtual machines cannot do, and probably better they didn't.

glide / video

sound

USB

Some of these among others aren't good candidates for VM's. For 90% VM's can give people what they need, for the other 10% people still need physical hardware.

[admin]

I think you misunderstood me. When I talk about running a 64-bit guest in an ESX VM, I mean ESX in a VM. For example, there are those who would like to run a 64-bit Linux guest under an ESX guest under Workstation running on a Windows host. Nesting VMs like this requires that the VT-x extensions be virtualized in the outermost VM...the one that has ESX installed in it.

[RParker]

I mean ESX in a VM

Ah ok! I see what you mean. I suppose that has purpose, but very limited in scope. For that matter you could simply install VM Server, and put ESX inside that on a Laptop.... Can you even run ESX in an ESX VM? I think there are limitations doing that.. but Workstation / Server can do it...

Besides ESX currently itself is NOT 64-bit so still no need to further Virtualize VT in a VM.

[admin]

ESX is schizophrenic. Though it is currently 32-bit for the most part, when you run a 64-bit VM, it does enter 64-bit mode. That's why you can only run 32-bit VMs inside an ESX VM today (using Server, Workstation, or Fusion to run your ESX VM). As long as you stick to 32-bit VMs, ESX sticks to 32-bit mode, and you're okay.

You can run ESX in VM under ESX as long as you can force complete hardware virtualization. For ESX 3.5 hosts, this means that you have to have AMD-V with RVI. See .

[RParker]

Ah thank you for that explanation. I learned something new today. Cool.

[Itzikr]

Hi,

any chance to make it work if i have an intel 7i cpu on my motherboard, running vm workstation and esx4..i want to try and install a windows server 2008 64bit as a vm, running in an esx4 vm that is running inside a vm workstation 6.5.2

Itzik Reich

Solutions Architect

VCP,VTSP,MCTS,MCITP,MCSE,CCA,CCNA

EMC²

where Information Lives

[admin]

No chance. Sorry about that.