Index: xen-4.2.0-testing/tools/python/xen/xm/cpupool.py
===================================================================
--- xen-4.2.0-testing.orig/tools/python/xen/xm/cpupool.py
+++ xen-4.2.0-testing/tools/python/xen/xm/cpupool.py
@@ -157,9 +157,17 @@ def make_cpus_config(cfg_cpus):
             #    ["0,2","1,3"]       -> [[0,2],[1,3]]
             #    ["0-3,^1","1-4,^2"] -> [[0,2,3],[1,3,4]]
             try:
-                for c in cfg_cpus:
-                    cpus = cnv(c)
-                    cpus_list.append(cpus)
+                cpus_str = ""
+                list_len = len(cfg_cpus)
+                n = 0
+                while n < list_len:
+                    if type(cfg_cpus[n]) != str:
+                        raise SyntaxError('cpus = %s' % cfg_cpus)
+                    cpus_str += cfg_cpus[n]
+                    n += 1
+                    if n < list_len:
+                        cpus_str += ', '
+                cpus_list = cnv(cpus_str)
             except ValueError, e:
                 raise err('cpus = %s: %s' % (cfg_cpus, e))
     else: