Question PCI Passthrough a dedicated GPU, use iGPU for host

Apr 27, 2019
Hi guys!

I have an old pc which is used as my home server running Ubuntu 18.04.
I would like to take advantage of PCI Passthrough to assign my dedicated 9400GT to a guest OS and use my integrated GPU on the host OS.
Now, I have been trying for weeks without any positive result.
First, it’s an old Siemens Esprimo P5720 with a D2584-A12 GS3 motherboard with an Intel Quad-Core Q9400. The CPU does support both VT-x and VT-d. In the BIOS, I have enabled both virtualization technology so it means, the motherboard supports them, too.

When I type lspci in the terminal, it only shows me the current VGA controller. If I set the primary display in the BIOS to the integrated GPU, lspci shows me the Intel VGA controller, if I set it to Auto, it shows the Nvidia card.
I followed different guides to add iommu=1 intel_iommu=on commands to grub and after reboot, it shows me that IOMMU is enabled with red text. However, it still doesn’t show both graphics controllers, just the current one.

Don’t say that you’re an idiot because you are using 10 year-old stuff please. I can’t just buy a new motherboard with 2 PCIe slots as I want to keep using my BTX(or what) case because it’s really really quite near my bed.👌

I would like to do the same thing as Linus did in their macOS virtualization video but not with 2 dedicated GPUs, just one and with my integrated one.

Is it possible somehow to use this feature on my system without replacing the whole server with newer hardware?

Thank you in advance for any form of help!

I will try to reply in hours because it’s 11:28 p.m. here, so sorry for not replying immediately! :D
Proxmox is a good os for it. Part of it even gui assisted. not much though. There is also some documentation for it.
It's fairly hardware picky. I believe it's the IOMMU groups. VT-x/d doesn't mean it has good groups.
From the research I've done the xeons + business chipsets usually have decent support. business boards have more features for it generally.

Found this guide. proxmox has one too but not really many tips on hardware in that one. View: