Index: root/xen-unstable.hg/tools/python/xen/xend/XendPIF.py
===================================================================
--- root.orig/xen-unstable.hg/tools/python/xen/xend/XendPIF.py
+++ root/xen-unstable.hg/tools/python/xen/xend/XendPIF.py
@@ -31,6 +31,22 @@ log.setLevel(logging.TRACE)
 MAC_RE = re.compile(':'.join(['[0-9a-f]{2}'] * 6))
 IP_IFACE_RE = re.compile(r'^\d+: (\w+):.*mtu (\d+) .* link/\w+ ([0-9a-f:]+)')
 
+modprobed_8021q = False
+ostype = os.uname()
+
+def linux_enable_vlan():
+    global modprobed_8021q
+    if not os.path.exists("/proc/net/vlan"):
+        if not modprobed_8021q:
+            modprobed_8021q = True
+            rc, o = commands.getstatusoutput("modprobe 8021q")
+            if rc != 0:
+                log.warn("Could not enable VLAN feature in kernel.")
+                return False
+        else:
+            return False
+    return True
+
 def linux_phy_to_virt(pif_name):
     return 'eth' + re.sub(r'^[a-z]+', '', pif_name)
 
@@ -91,6 +107,9 @@ def linux_set_mtu(iface, mtu):
         return False
 
 def _create_VLAN(dev, vlan):
+    if ostype == "Linux" and linux_enable_vlan() == False:
+        return False
+
     rc, _ = commands.getstatusoutput('vconfig add %s %d' %
                                      (dev, vlan))
     if rc != 0: