VGA Passthrough crashes machine

[Anthony Wright <anthony@overnetdata.com>]

I've just had my first attempt at getting VGA passthrough to work, and
it crashed the machine. I'm trying to understand whether this is a
problem with my hardware, configuration or a software problem.

I'm running Xen 4.1.2 with Linux 3.1.2


The CPU is an Intel Core i5-650
http://ark.intel.com/products/43546/Intel-Core-i5-650-Processor-%284M-Cache-3_20-GHz%29

The Video Card is and Intel Core Processor Integrated Graphics Controller
PCI ID: 8086 0042


I have hidden the vga device with xen-pciback.hide=(00:02.0) on the
kernel command line

The xen config file is:
name        = '11-1'
kernel            = '/usr/lib/xen/boot/hvmloader'
builder           = 'hvm'
device_model      = '/usr/lib/xen/bin/qemu-dm'
boot              = 'c'
serial            = 'pty'
usbdevice         = 'tablet'
disk        = [ 'phy:/dev/Master/Root-11-0001,hda,w' ]
memory      = 1000
vif         = [
'bridge=br-internal,mac=04:fb:7a:22:e8:4a','bridge=br-dmz,mac=04:fb:7a:22:e8:4b','bridge=br-local,mac=04:fb:7a:22:e8:4c'
]
vcpus       = 1
on_poweroff = 'destroy'
on_reboot   = 'destroy'
on_crash    = 'destroy'

gfx_passthru=1
pci=['00:02.0']

When I try to start the DomU I get the following output, I get the
prompt back and then the system reboots.

Parsing config file xen-config
xc: info: VIRTUAL MEMORY ARRANGEMENT:
  Loader:        0000000000100000->00000000001795d0
  TOTAL:         0000000000000000->000000003e000000
  ENTRY ADDRESS: 0000000000100000
xc: info: PHYSICAL MEMORY ALLOCATION:
  4KB PAGES: 0x0000000000000200
  2MB PAGES: 0x00000000000001ef
  1GB PAGES: 0x0000000000000000
libxl: error: libxl_pci.c:712:do_pci_add xc_assign_device failed
Daemon running with PID 2050