[vfio-users] Trying to pass through USB controller.

[Andrew A.]

Hi Samuel and the list,

I'm reviving this old thread in the hopes that you or another user may
know the answer to a question I have. The full thread is here:
https://www.redhat.com/archives/vfio-users/2016-February/msg00110.html

Here's a bit of context, followed by my question:
> In short, "sudo setpci -s0:14.0 0xd0.W=0x0000" will pass through all of
> your ports.
>
> I was planning to write a blog post about it this month, but I haven't
> gotten to it yet, so I guess I'll write it here. I have been using this
> setup since December, and everything works without any issues. I had
> done like you (playing with the firmware options) and gotten nowhere; I
> finally found a Google+ post[0] (the user appears to have been deleted)
> with a link to the 9 series PCH datasheet[1], which has been immensely
> useful.

This technique worked really well for me. I'm passing through my XHCI
controller to the guest and use my EHCI controllers in the host. This
is because I need the extra performance of USB 3.0 in my guest moreso
than the host. The only problem with this approach is that upon
bootup, usb devices will not work on my host until I run the setpci
command and get some ports (i.e. my keyboard/mouse) routed over to
EHCI. This isn't so bad, since I can stick setpci in my startup script
and be on my way, but what I've also found is that when a qemu/kvm
guest starts up, it sends some kind of pci reset to the vfio pci
device that's being passed through (the XHCI controller, in this
case), and that causes my port routings to get reset again. I have to
run setpci yet again to get my mouse/keyboard working again on the
host.

Does anyone know of a sensible way to more permanently set the port
routing mask so it survives these pci resets?

Thanks for writing this up last year,

Andrew