Allow changing vcpu count in the persistent config.

Changes similar to what was done with memory: try cpu hotplug, and always
follow up with XML definition.

src/virtManager/details.py

@@ -1603,7 +1603,26 @@ class vmmDetails(gobject.GObject):
         vcpus = self.window.get_widget("config-vcpus").get_adjustment().value
         logging.info("Setting vcpus for %s to %s" % (self.vm.get_name(),
                                                      str(vcpus)))
-        self.vm.set_vcpu_count(vcpus)
+        hotplug_err = False
+
+        try:
+            if self.vm.is_active():
+                self.vm.hotplug_vcpus(vcpus)
+        except Exception, e:
+            logging.debug("VCPU hotplug failed: %s" % str(e))
+            hotplug_err = True
+
+        # Change persistent config
+        try:
+            self.vm.define_vcpus(vcpus)
+        except Exception, e:
+            self.err.show_err(_("Error changing vcpu value: %s" % str(e)),
+                              "".join(traceback.format_exc()))
+            return False
+
+        if hotplug_err:
+            self.err.show_info(_("These changes will take effect after the "
+                                 "next guest reboot. "))
 
     def config_get_maxmem(self):
         maxadj = self.window.get_widget("config-maxmem").get_adjustment()
@@ -1657,7 +1676,7 @@ class vmmDetails(gobject.GObject):
             logging.debug("Memory hotplug failed: %s" % str(e))
             hotplug_err = True
 
-        # Change persisten config
+        # Change persistent config
         try:
             self.vm.define_both_mem(curmem, maxmem)
         except Exception, e:

src/virtManager/domain.py

@@ -180,14 +180,15 @@ class vmmDomain(gobject.GObject):
         if origxml == newxml:
             logging.debug("Redefinition requested, but new xml was not"
                           " different")
-            return
 
-        diff = "".join(difflib.unified_diff(origxml.splitlines(1),
-                                            newxml.splitlines(1),
-                                            fromfile="Original XML",
-                                            tofile="New XML"))
-        logging.debug("Redefining '%s' with XML diff:\n%s",
-                      self.get_name(), diff)
+        else:
+            diff = "".join(difflib.unified_diff(origxml.splitlines(1),
+                                                newxml.splitlines(1),
+                                                fromfile="Original XML",
+                                                tofile="New XML"))
+            logging.debug("Redefining '%s' with XML diff:\n%s",
+                          self.get_name(), diff)
+
         self.get_connection().define_domain(newxml)
 
         # Invalidate cached XML
@@ -1295,9 +1296,30 @@ class vmmDomain(gobject.GObject):
         logging.debug("eject_cdrom produced: %s" % result)
         self._change_cdrom(result, dev_id_info)
 
-    def set_vcpu_count(self, vcpus):
+    def hotplug_vcpu(self, vcpus):
+        self.vm.setVcpus()
+
+    def hotplug_vcpus(self, vcpus):
         vcpus = int(vcpus)
-        self.vm.setVcpus(vcpus)
+        if vcpus != self.vcpu_count():
+            self.vm.setVcpus(vcpus)
+
+    def define_vcpus(self, vcpus):
+        vcpus = int(vcpus)
+
+        def set_node(doc, ctx, val, xpath):
+            node = ctx.xpathEval(xpath)
+            node = (node and node[0] or None)
+
+            if node:
+                node.setContent(str(val))
+            return doc.serialize()
+
+        def change_vcpu_xml(xml, vcpus):
+            return util.xml_parse_wrapper(xml, set_node, vcpus,
+                                          "/domain/vcpu[1]")
+
+        self.redefine(change_vcpu_xml, vcpus)
 
     def hotplug_memory(self, memory):
         if memory != self.get_memory():