Xen devel - Jun 2012 - Intel VGA-passthrough to Ubuntu12.04 64bit Dom-U doesn't work

Hi,
When Ubuntu12.04 64bit domU boot up, Intel VGA-passthrough doesn''t
work.
I used the command "xm create" to boot up Dom-U.
Windows7-64bit-SP1 works quite well with same configuration.
Boot log is as follows.

Dom-U dmesg:
[    1.421858] initcall rfcomm_init+0x0/0xf1 [rfcomm] returned 0 after
2192 usecs
[    1.423021] calling  i915_init+0x0/0x8d [i915] @ 387
[    1.423023] [drm:drm_pci_init],
[    1.423038] [drm:drm_get_pci_dev],
[    1.423157] xen: --> pirq=55 -> irq=24 (gsi=24)
[    1.423159] i915 0000:00:02.0: PCI INT A -> GSI 24 (level, low) -> IRQ
24
[    1.423224] i915 0000:00:02.0: setting latency timer to 64
[    1.423315] [drm:drm_get_minor],
[    1.423411] initcall alsa_timer_init+0x0/0x1000 [snd_timer] returned
0 after 1559 usecs
[    1.423528] [drm:drm_get_minor], new minor assigned 64
[    1.423529] [drm:drm_get_minor],
[    1.423620] [drm:drm_get_minor], new minor assigned 0
[    1.474532] [drm:intel_opregion_setup], graphic opregion physical
addr: 0xfeff5018
[    1.474545] resource map sanity check conflict: 0xfeff5018 0xfeff7017
0xfeff7000 0xffffffff reserved
[    1.474547] ------------[ cut here ]------------
[    1.474551] WARNING: at
/build/buildd/linux-3.2.0/arch/x86/mm/ioremap.c:171
__ioremap_caller+0x382/0x390()
[    1.474553] Hardware name: HVM domU
[    1.474554] Info: mapping multiple BARs. Your kernel is fine.
[    1.474555] Modules linked in: i915(+) snd_timer snd_seq_device
rfcomm drm_kms_helper psmouse snd serio_raw drm mac_hid bnep
i2c_algo_bit shpchp soundcore bluetooth video parport_pc ppdev
snd_page_alloc i2c_piix4 lp parport floppy
[    1.474568] Pid: 387, comm: modprobe Not tainted 3.2.0-23-generic
#36-Ubuntu
[    1.474570] Call Trace:
[    1.474574]  [<ffffffff8106712f>] warn_slowpath_common+0x7f/0xc0
[    1.474576]  [<ffffffff81067226>] warn_slowpath_fmt+0x46/0x50
[    1.474578]  [<ffffffff81041002>] __ioremap_caller+0x382/0x390
[    1.474592]  [<ffffffffa01876da>] ? intel_opregion_setup+0x7a/0x220
[i915]
[    1.474594]  [<ffffffff81041044>] ioremap_cache+0x14/0x20
[    1.474603]  [<ffffffffa01876da>] intel_opregion_setup+0x7a/0x220
[i915]
[    1.474611]  [<ffffffffa0149744>] i915_driver_load+0x1a4/0x720 [i915]
[    1.474618]  [<ffffffffa00bffb9>] drm_get_pci_dev+0x199/0x300 [drm]
[    1.474620]  [<ffffffff8103dbb9>] ? default_spin_lock_flags+0x9/0x10
[    1.474630]  [<ffffffffa018a2a7>] i915_pci_probe+0x1b/0x1d [i915]
[    1.474633]  [<ffffffff8133447c>] local_pci_probe+0x5c/0xd0
[    1.474635]  [<ffffffff81335d29>] __pci_device_probe+0xf9/0x100
[    1.474638]  [<ffffffff8130cd2a>] ? kobject_get+0x1a/0x30
[    1.474640]  [<ffffffff81335d6a>] pci_device_probe+0x3a/0x60
[    1.474643]  [<ffffffff813f4eb8>] really_probe+0x68/0x190
[    1.474645]  [<ffffffff813f5145>] driver_probe_device+0x45/0x70
[    1.474646]  [<ffffffff813f521b>] __driver_attach+0xab/0xb0
[    1.474648]  [<ffffffff813f5170>] ? driver_probe_device+0x70/0x70
[    1.474650]  [<ffffffff813f5170>] ? driver_probe_device+0x70/0x70
[    1.474651]  [<ffffffff813f3fac>] bus_for_each_dev+0x5c/0x90
[    1.474653]  [<ffffffff813f4c7e>] driver_attach+0x1e/0x20
[    1.474655]  [<ffffffff813f48d0>] bus_add_driver+0x1a0/0x270
[    1.474657]  [<ffffffff813f5786>] driver_register+0x76/0x140
[    1.474659]  [<ffffffff81335a06>] __pci_register_driver+0x56/0xd0
[    1.474664]  [<ffffffffa00c023a>] drm_pci_init+0x11a/0x130 [drm]
[    1.474667]  [<ffffffff8100a669>] ? xen_clocksource_get_cycles+0x9/0x10
[    1.474669]  [<ffffffffa01b9000>] ? 0xffffffffa01b8fff
[    1.474675]  [<ffffffffa01b908b>] i915_init+0x8b/0x8d [i915]
[    1.474678]  [<ffffffff8100212c>] do_one_initcall+0x12c/0x180
[    1.474681]  [<ffffffff810a886e>] sys_init_module+0xbe/0x230
[    1.474683]  [<ffffffff81664a82>] system_call_fastpath+0x16/0x1b
[    1.474685] ---[ end trace 7589c8eed3077f77 ]---

Hardware:
Dell Optiplex 990
Core i5 2500
Display connected via VGA

Software:
dom0 kernel : Linux 3.4.0 64bit
domU kernel : Linux 3.2.0-23-generic 64bit(Ubuntu12.04 LTS)
xen 4.2-unstable(Latest ChangeSet: Thu May 31 10:18:52 2012 +0200
25432:d7318231cfe3)

Dom-U configuration file:
#  -*- mode: python; -*-
kernel = "hvmloader"
builder=''hvm''
name = "domU"
vcpus=1
device_model = ''qemu-dm''
serial=''pty''
usb=1
usbdevice=''tablet''
memory = 2048
on_poweroff = "destroy"
on_reboot = "restart"
on_crash = "restart"
disk = [ ''file:/etc/xen/ubuntu.img,hda,w'' ]
vscsi = [ ''2:0:0:0, host'' ]
pci=[ ''00:02.0'', ''00:1b.0'',
''00:1a.0'', ''00:1d.0'' ]
gfx_passthru=1
vif = [ ''type=ioemu, bridge=xenbr0, model=e1000'' ]
keymap=''ja''


Thanks,
SANO