Customising CPUID

ThinkChaos

Hello,

I'd like to change the CPUID for a VM. I found the cpuid config option for xl.conf, but don't know where this should be set.
I'm new to Xen and XCP-ng.

Could someone point me in the right direction?
Thanks!

olivierlambert

Hi,

XAPI doesn't work like xl, it's using xe. Can you describe your use case?

ThinkChaos

I'm trying to trick the nVidia drivers in Windows for GPU passthrough.

I tried patching the drivers with sk1080/nvidia-kvm-patcher, but that didn't work for me. So I'm trying to hide the virtualized bit in CPUID.

Where could I read more about xl vs xe and XAPI?

olivierlambert

I assume you mean "consumer grade Nvidia GPUs" for passthrough, because it works out of the box with Quadro GPUs.

It's far harder than this, see https://lists.xenproject.org/archives/html/xen-devel/2016-07/msg01716.html

As long we don't know what Nvidia driver is checking exactly, we'll be in the dark to find a way to hide it.

ThinkChaos

Yeah I'm working with a GTX 960. I guess I'll try something else then. Thanks for the replies.

olivierlambert

If you know exactly what's checked in the driver (CPU vendor, ACPI tables, BIOS info, SMI?), we might be able to dig into the right direction. It's just that I won't spend a lot of resources without knowing if our modifications are useful or not.