I'm Guilherme Suzuki and a couple of months ago I've been trying to VGA passthrough a Radeon HD 7950 to a virtual machine. I'm currently using XEN in a fedora 18.
Long story short, it worked. But, if I reboot the virtual machine (due to anything, such as windows update) and try to boot it up again, windows 7 device manager tells me that Radeon couldn't start (code 10 or 43). It will only come back again, if I reboot the PC first .
Legend says that FLR is a requirement in a VGA device to passthru itself (along with motherboard vt-d). Prompting lspci -vv command in my fedora 18, I only see FLR capability from onboard VGA devices (intel hd graphics, sandy or ivy bridge) and virtual machines do work with them (like a normal PC).
So, here's the question: is there another way to enable FLR capability, by applying a different firmware?