VM: Windows 7 host, Linux guest, VT-d?

Question

I am sick of the driver issues of Linux. So I am planning to switch to Windows 7 as a host and virtualize my Linux into it. My laptop has integrated Intel graphics and supports VT-d. For speed reasons I would like to assign that card to Linux. Now, Parallels could do it but this page says

Note: If you have only one PCIe video adapter, its name will be grayed out in the PCI Devices list and you will not be able to allocate it to your virtual machines.

I would be perfectly fine with a headless Windows 7 (I can remotely admin from other computers or just the Linux guest) -- is there any VM software that doesn't have this restriction?

Answer 1

This is not restriction of the VM software. Device passthrough is based on IOMMU by re-mapping device addresses and providing to the guest. Hardware can be mapped by just one machine, physical or virtual, so if your guests needs direct I/O to some hardware, you should have it 1:1. IOMMU must be supported by CPU (search for Intel VT-d or AMD-Vi), chipset, BIOS and OS + VM solution.

Next you can meet big problem with VGA pass-through, it's little more complicated, but possible. Make some research, you can start here. But you can only solve this with more than one VGA, because that one is already initialized.

UPDATE: probably it's possible to pass primary display with xen-pciback.hide in kernel command-line (source)

If you want Win7 as a host with VirtualBox/VMware/Hyper-V/etc, your Linux guest should run without problems on fully virtualized VGA. I presume you want to use Linux for reasons other than GPU tasks like vido-gaming, this can handle Windows.