xend: Add blktap disk type check

Print the following error when you give a wrong disk type to xm commands:
 # xm create /xen/vm1.conf disk='tap:xxx:/xen/root-vm1.img,hda1,w'
 Using config file "/xen/vm1.conf".
 Error: tap:xxx not a valid disk type

 # xm block-attach vm2 tap:yyy:/xen/second.img hdb1 w
 Error: tap:yyy not a valid disk type
 Usage: xm block-attach <Domain> <BackDev> <FrontDev> <Mode>
 [BackDomain]

Signed-off-by: Masaki Kanno <kanno.masaki@jp.fujitsu.com>

tools/python/xen/xend/XendConfig.py

@@ -28,6 +28,7 @@ from xen.xend.XendError import VmError
 from xen.xend.XendDevices import XendDevices
 from xen.xend.PrettyPrint import prettyprintstring
 from xen.xend.XendConstants import DOM_STATE_HALTED
+from xen.xend.server.BlktapController import blktap_disk_types
 from xen.xend.server.netif import randomMAC
 from xen.util.blkif import blkdev_name_to_number
 from xen.util import xsconstants
@@ -1084,6 +1085,11 @@ class XendConfig(dict):
                 else:
                     dev_info['driver'] = 'paravirtualised'
 
+            if dev_type == 'tap':
+                if dev_info['uname'].split(':')[1] not in blktap_disk_types:
+                    raise XendConfigError("tap:%s not a valid disk type" %
+                                    dev_info['uname'].split(':')[1])
+
             if dev_type == 'vif':
                 if not dev_info.get('mac'):
                     dev_info['mac'] = randomMAC()

tools/python/xen/xend/server/BlktapController.py

@@ -7,6 +7,14 @@ from xen.xend.XendLogging import log
 phantomDev = 0;
 phantomId = 0;
 
+blktap_disk_types = [
+    'aio',
+    'sync',
+    'vmdk',
+    'ram',
+    'qcow'
+    ]
+
 class BlktapController(BlkifController):
     def __init__(self, vm):
         BlkifController.__init__(self, vm)