virt: disk target device depends on the bus

Not all disk target devices should start with 'vd' for non-vmware
hypervisors. Map the bus type to the right device name prefix. While at
it, also make sure the disks are created right for xen.

salt/modules/virt.py

@@ -615,16 +615,17 @@ def _gen_xml(name,
             context['console'] = True
 
     context['disks'] = {}
+    disk_bus_map = {'virtio': 'vd', 'xen': 'xvd', 'fdc': 'fd', 'ide': 'hd'}
     for i, disk in enumerate(diskp):
         context['disks'][disk['name']] = {}
         context['disks'][disk['name']]['file_name'] = disk['filename']
         context['disks'][disk['name']]['source_file'] = disk['source_file']
-        if hypervisor in ['qemu', 'kvm', 'bhyve']:
-            context['disks'][disk['name']]['target_dev'] = 'vd{0}'.format(string.ascii_lowercase[i])
+        prefix = disk_bus_map.get(disk['model'], 'sd')
+        context['disks'][disk['name']]['target_dev'] = '{0}{1}'.format(prefix, string.ascii_lowercase[i])
+        if hypervisor in ['qemu', 'kvm', 'bhyve', 'xen']:
             context['disks'][disk['name']]['address'] = False
             context['disks'][disk['name']]['driver'] = True
         elif hypervisor in ['esxi', 'vmware']:
-            context['disks'][disk['name']]['target_dev'] = 'sd{0}'.format(string.ascii_lowercase[i])
             context['disks'][disk['name']]['address'] = True
             context['disks'][disk['name']]['driver'] = False
         context['disks'][disk['name']]['disk_bus'] = disk['model']