[libvirt] libvirt error while start vm with VGA passthrough

http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Virtual... I have followed the instructions in the RedHat reference above to the best of my ability to understand them. I add the pci multi-port serial io card through virt-manager and it was indeed entered into the virtual machine's configuration file inside the <devices> tag: <hostdev mode='subsystem' type='pci' managed='yes'> <source> <address domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </source> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/> </hostdev> However, when I try and start the virtual machine I get this error: Error starting domain: internal error Unable to reset PCI device 0000:00:03.0: no FLR, PM reset or bus reset available Traceback (most recent call last): File "/usr/share/virt-manager/virtManager/asyncjob.py", line 44, in cb_wrapper callback(asyncjob, *args, **kwargs) File "/usr/share/virt-manager/virtManager/asyncjob.py", line 65, in tmpcb callback(*args, **kwargs) File "/usr/share/virt-manager/virtManager/domain.py", line 1050, in startup self._backend.create() File "/usr/lib64/python2.6/site-packages/libvirt.py", line 511, in create if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self) libvirtError: internal error Unable to reset PCI device 0000:00:03.0: no FLR, PM reset or bus reset available The steps I followed were: 1. Check VT-D extensions available and enabled in BIOS - yes 2. Restart virtual host - yes 3. Identify device - yes <address domain='0x000' bus='0x00' slot='0x03' function='0x0'/> 4. Add device to virtual machine configuration - yes . . . <hostdev mode='subsystem' type='pci' managed='yes'> <source> <address domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </source> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/> </hostdev> <memballoon model='virtio'> <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/> </memballoon> </devices> </domain> 5. Start virtual machine - fails Am I making any obvious errors?