diff --git a/neutron/plugins/ml2/drivers/mech_sriov/agent/eswitch_manager.py b/neutron/plugins/ml2/drivers/mech_sriov/agent/eswitch_manager.py
index 201c3c3..56f0d32 100644
--- a/neutron/plugins/ml2/drivers/mech_sriov/agent/eswitch_manager.py
+++ b/neutron/plugins/ml2/drivers/mech_sriov/agent/eswitch_manager.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import itertools
 import os
 import re
 
@@ -270,9 +271,11 @@ class ESwitchManager(object):
             embedded_switch = self.emb_switches_map.get(phys_net, None)
             if not embedded_switch:
                 return set()
-            eswitch_objects = [embedded_switch]
+            eswitch_objects = embedded_switch
         else:
-            eswitch_objects = self.emb_switches_map.values()
+            eswitch_objects = set(
+                itertools.chain.from_iterable(
+                    six.itervalues(self.emb_switches_map)))
         assigned_devices = set()
         for embedded_switch in eswitch_objects:
             for device in embedded_switch.get_assigned_devices_info():
@@ -347,7 +350,7 @@ class ESwitchManager(object):
 
     def _create_emb_switch(self, phys_net, dev_name, exclude_devices):
         embedded_switch = EmbSwitch(phys_net, dev_name, exclude_devices)
-        self.emb_switches_map[phys_net] = embedded_switch
+        self.emb_switches_map.setdefault(phys_net, []).append(embedded_switch)
         for pci_slot in embedded_switch.get_pci_slot_list():
             self.pci_slot_map[pci_slot] = embedded_switch