Can't install XEN guest on Fedora 22

[Jens Pelzetter]

Hello everyone,

we have a system (Sun Fire V40z) here were we can only do
Para-Virtualisation using Xen because the CPU does not have
Virtualization Support. With CentOS 6.6 everythink worked fine. We
decided to reinstall the system with Fedora Server 22 because we needed
some more up to date packages.

Now we are stuck with Xen. If we try to create a guest using
Virt-Manager we get this error:

Unable to complete install: 'cannot fill file
'/var/lib/xen/virtinst-vmlinuz.WtErnB': Invalid argument'

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 89, in
cb_wrapper
    callback(asyncjob, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/create.py", line 1855, in
do_install
    guest.start_install(meter=meter)
  File "/usr/share/virt-manager/virtinst/guest.py", line 386, in
start_install
    self._prepare_install(meter, dry)
  File "/usr/share/virt-manager/virtinst/guest.py", line 279, in
_prepare_install
    self.installer.prepare(self, meter)
  File "/usr/share/virt-manager/virtinst/installer.py", line 200, in prepare
    self._prepare(guest, meter)
  File "/usr/share/virt-manager/virtinst/distroinstaller.py", line 461,
in _prepare
    self._prepare_kernel_url(guest, fetcher)
  File "/usr/share/virt-manager/virtinst/distroinstaller.py", line 382,
in _prepare_kernel_url
    fetcher.meter, kernel, initrd)
  File "/usr/share/virt-manager/virtinst/distroinstaller.py", line 290,
in _upload_media
    kvol = _upload_file(conn, meter, pool, kernel)
  File "/usr/share/virt-manager/virtinst/distroinstaller.py", line 124,
in _upload_file
    disk.setup(meter=meter)
  File "/usr/share/virt-manager/virtinst/devicedisk.py", line 812, in setup
    volobj = self._storage_creator.create(meter)
  File "/usr/share/virt-manager/virtinst/diskbackend.py", line 352, in
create
    return self._vol_install.install(meter=progresscb)
  File "/usr/share/virt-manager/virtinst/storage.py", line 733, in install
    vol = self.pool.createXML(xml, createflags)
  File "/usr/lib64/python2.7/site-packages/libvirt.py", line 3164, in
createXML
    if ret is None:raise libvirtError('virStorageVolCreateXML() failed',
pool=self)
libvirtError: cannot fill file '/var/lib/xen/virtinst-vmlinuz.WtErnB':
Invalid argument

Does anyone have an idea what is causing this and how to solve the problem?

Thanks.

Best regards

Jens