SLES12. On a test box i installed Xen then tried to create a VM but would get:

Unable to complete install: 'internal error: libxenlight failed to create new domain '2012r2lab''

Traceback (most recent call last):
File "/usr/share/virt-manager/virtManager/asyncjob.py", line 91, in cb_wrapper
callback(asyncjob, *args, **kwargs)
File "/usr/share/virt-manager/virtManager/create.py", line 1908, in do_install
guest.start_install(meter=meter)
File "/usr/share/virt-manager/virtinst/guest.py", line 426, in start_install
noboot)
File "/usr/share/virt-manager/virtinst/guest.py", line 490, in _create_guest
dom = self.conn.createLinux(start_xml or final_xml, 0)
File "/usr/lib64/python2.7/site-packages/libvirt.py", line 3297, in createLinux
if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self)
libvirtError: internal error: libxenlight failed to create new domain '2012r2lab'

I installed KVM and rebooted the server. Then and only then was i able to create a VM.

So my question is 2 fold:
Which hypervisor to install? and
Do you need to install anything else when you first run the yast applet install hypervisor and tools?