Xen will not start VMs in 11.2m6

11.2Milestone6 x86_64 default Xfce+Xen Host Server+console tools install, dual Xeon E5530 DP, 48GB RAM.

Try to install either another 11.2m6 or an 11.1 virtual machine with vm-install, Get "Error Failed to Start the VM/ Details Error: unknown opcode" display. Xend.log records:

[2009-08-21 22:56:28 3215] DEBUG (XendDomainInfo:2757) XendDomainInfo.destroy: domid=3
[2009-08-21 22:56:28 3215] DEBUG (XendDomainInfo:2227) Destroying device model
[2009-08-21 22:56:28 3215] ERROR (XendDomainInfo:2230) Device model destroy failed X86_Linux_ImageHandler instance has no attribute 'sentinel_lock'
Traceback (most recent call last):
File "/usr/lib64/python2.6/site-packages/xen/xend/XendDomainInfo.py", line 2228, in _releaseDevices
self.image.destroyDeviceModel()
File "/usr/lib64/python2.6/site-packages/xen/xend/image.py", line 573, in destroyDeviceModel
self.sentinel_lock.acquire()
AttributeError: X86_Linux_ImageHandler instance has no attribute 'sentinel_lock'
[2009-08-21 22:56:28 3215] DEBUG (XendDomainInfo:2234) Releasing devices
[2009-08-21 22:56:28 3215] ERROR (xmlrpclib2:178) Internal error handling xend.domain.start
Traceback (most recent call last):
File "/usr/lib64/python2.6/site-packages/xen/util/xmlrpclib2.py", line 131, in _marshaled_dispatch
response = self._dispatch(method, params)
File "/usr/lib64/python2.6/SimpleXMLRPCServer.py", line 418, in _dispatch
return func(*params)
File "/usr/lib64/python2.6/site-packages/xen/xend/XendDomain.py", line 1040, in domain_start
dominfo.start(is_managed = True)
File "/usr/lib64/python2.6/site-packages/xen/xend/XendDomainInfo.py", line 459, in start
XendTask.log_progress(31, 60, self._initDomain)
File "/usr/lib64/python2.6/site-packages/xen/xend/XendTask.py", line 209, in log_progress
retval = func(*args, **kwds)
File "/usr/lib64/python2.6/site-packages/xen/xend/XendDomainInfo.py", line 2580, in _initDomain
channel_details = self.image.createImage()
File "/usr/lib64/python2.6/site-packages/xen/xend/image.py", line 156, in createImage
return self.createDomain()
File "/usr/lib64/python2.6/site-packages/xen/xend/image.py", line 175, in createDomain
result = self.buildDomain()
File "/usr/lib64/python2.6/site-packages/xen/xend/image.py", line 994, in buildDomain
self.setCpuid()
File "/usr/lib64/python2.6/site-packages/xen/xend/image.py", line 621, in setCpuid
def setCpuid(self):
SystemError: unknown opcode

lspci output:
00:00.0 Host bridge: Intel Corporation X58 I/O Hub to ESI Port (rev 13)
00:01.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 1 (rev 13)
00:03.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 3 (rev 13)
00:07.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 7 (rev 13)
00:09.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 9 (rev 13)
00:0e.0 Host bridge: Intel Corporation Device 341c (rev 13)
00:0e.1 Host bridge: Intel Corporation Device 341d (rev 13)
00:0e.2 Host bridge: Intel Corporation Device 341e (rev 13)
00:10.0 PIC: Intel Corporation X58 Physical and Link Layer Registers Port 0 (rev 13)
00:10.1 PIC: Intel Corporation X58 Routing and Protocol Layer Registers Port 0 (rev 13)
00:11.0 PIC: Intel Corporation QuickPath Interconnect Physical and Link Layer Registers Port 1 (rev 13)
00:11.1 PIC: Intel Corporation QuickPath Interconnect Routing and Protocol Layer Registers Port 1 (rev 13)
00:14.0 PIC: Intel Corporation X58 I/O Hub System Management Registers (rev 13)
00:14.1 PIC: Intel Corporation X58 I/O Hub GPIO and Scratch Pad Registers (rev 13)
00:14.2 PIC: Intel Corporation X58 I/O Hub Control Status and RAS Registers (rev 13)
00:14.3 PIC: Intel Corporation X58 I/O Hub Throttle Registers (rev 13)
00:16.0 System peripheral: Intel Corporation X58 Chipset QuickData Technology Device (rev 13)
00:16.1 System peripheral: Intel Corporation X58 Chipset QuickData Technology Device (rev 13)
00:16.2 System peripheral: Intel Corporation X58 Chipset QuickData Technology Device (rev 13)
00:16.3 System peripheral: Intel Corporation X58 Chipset QuickData Technology Device (rev 13)
00:16.4 System peripheral: Intel Corporation DMA Engine (rev 13)
00:16.5 System peripheral: Intel Corporation DMA Engine (rev 13)
00:16.6 System peripheral: Intel Corporation DMA Engine (rev 13)
00:16.7 System peripheral: Intel Corporation DMA Engine (rev 13)
00:1a.0 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #4
00:1a.1 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #5
00:1a.2 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #6
00:1a.7 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB2 EHCI Controller #2
00:1d.0 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #1
00:1d.1 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #2
00:1d.2 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #3
00:1d.7 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB2 EHCI Controller #1
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 90)
00:1f.0 ISA bridge: Intel Corporation 82801JIB (ICH10) LPC Interface Controller
00:1f.3 SMBus: Intel Corporation 82801JI (ICH10 Family) SMBus Controller
01:01.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200eW WPCM450 (rev 0a)
02:00.0 Serial Attached SCSI controller: LSI Logic / Symbios Logic SAS2008 PCI-Express Fusion-MPT SAS-2 [Falcon] (rev 02)
05:00.0 Ethernet controller: Intel Corporation 82576 Gigabit Network Connection (rev 01)
05:00.1 Ethernet controller: Intel Corporation 82576 Gigabit Network Connection (rev 01)