Sorry for my fault that I just sent  this mail
to xen-devel  first.
 
 
Hi,everyone
I am trying to use VHD disk format on
guestVM. 
 
My environment is  fedora12+
xen-4.0.1-rc6 + xen-stable/2.6.32.15+libvirt-0.8.3
 
I success on booting VM in VHD disk
correctly using “xm create VM.cfg” and everything runs alright 
 
Where disk = [
"tap2:vhd:/root/tapdisk/vhd-f12,hda,w"]   in VM.cfg
And “vhd-f12” is
a VHD type image file created by  vhd-util.
 
However, when I trying to use virsh dumpxml
 to dump guestVM’s xml file, there’s no any disk information in the xml. 
 
 
On the other hand, I also tried to add the
following part into xml manually and then use “virsh create VM.xml“ to create
guestVM
 
<disk type='file' device='disk'>
      <driver
name='tap' type='vhd'/>
      <source
file='/root/tapdisk/vhd-f12'/>
      <target
dev='hda' bus='ide'/>
</disk>
 
but guestVM can be started without error
but guestVM cannot get disk device correctly. 
 
If I replace driver name='tap’ to ‘tap2’,
libvirt raise error:
(xend.err 'Error creating domain: Block
device type "tap2" is invalid.')
 
 
Is anyone has idea how can I enable vhd
format using libvirt? 
 
Thank very much!
 
Ben