Description of problem:
Since libvirt started adding multifunction=on to PCI devices, SPICE/QXL multihead support in Windows no longer works.

Version-Release number of selected component (if applicable):

libvirt-0.9.3-1.el6

Steps to Reproduce:
1. Create a Windows XP guest with SPICE graphics + QXL display adapter
2. Install QXL graphics device driver in Windows
3. Stop the guest
4. Add a second <video> element to the guest for QXL display adapter
5. Start the guest again
6. Configure the QXL device driver for the second display

Actual results:
Windows fails to start the QXL device driver with an error 'Code 10'

Expected results:
The second device is initialized.

---

In response to a suggestion by Dan Berrange on libvir-list:

  https://www.redhat.com/archives/libvir-list/2011-September/msg01036.html

I pushed the following patch to upstream libvirt, which removes the automatic setting of the multifunction bit, in favor of an XML attribute to turn it on as desired:

commit c329db7180d77c8077b9f9cd167a71d7f347227a
Author: Laine Stump <laine>
Date:   Thu Sep 29 13:00:32 2011 -0400

    qemu: make PCI multifunction support more manual
    
This allows exact control of when the multifunction bit should be turned on/off for each slot/function on the guest's PCI bus, eliminating the issue with the QXL driver's (and possibly/probably other drivers') lack of multifunction support.