cli: Make --cpu host-model and --cpu host-passthrough work

tests/cli-test-xml/compare/virtxml-stdin-edit.xml

@@ -14,7 +14,5 @@
   <on_crash>destroy</on_crash>
   <devices>
   </devices>
-  <cpu mode="custom" match="exact">
-    <model>host-passthrough</model>
-  </cpu>
+  <cpu mode="host-passthrough"/>
 </domain>

tests/clitest.py

@@ -1014,7 +1014,7 @@ promptlist.append(p7)
 
 p8 = PromptTest("virt-xml --connect %(TESTURI)s --confirm test "
     "--edit --cpu host-passthrough")
-p8.add("Define 'test' with the changed XML", "yes", num_lines=12)
+p8.add("Define 'test' with the changed XML", "yes", num_lines=10)
 promptlist.append(p8)
 
 

virtinst/cli.py

@@ -1438,6 +1438,9 @@ class ParserCPU(VirtCLIParser):
             elif (val == "host-model-only" and
                   self.guest.conn.caps.host.cpu.model):
                 inst.cpu.model = self.guest.conn.caps.host.cpu.model
+            elif val == "host-model" or val == "host-passthrough":
+                inst.cpu.model = None
+                inst.cpu.mode = val
             else:
                 inst.cpu.model = val
 
@@ -1458,6 +1461,7 @@ class ParserCPU(VirtCLIParser):
                     inst.cpu.add_feature(feature_name, policy)
 
         self.set_param(None, "model", setter_cb=set_model_cb)
+        self.set_param("cpu.mode", "mode")
         self.set_param("cpu.match", "match")
         self.set_param("cpu.vendor", "vendor")