tpm: add TPM emulator backend

An emulated backend doesn't require any path, since libvirt will take
care of finding the emulator and managing the storage. However, the
version to emulate can be specified.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

tests/cli-test-xml/compare/virt-install-singleton-config-2.xml

@@ -148,6 +148,9 @@
         <device path="/dev/tpm0"/>
       </backend>
     </tpm>
+    <tpm model="tpm-crb">
+      <backend type="emulator" version="2.0"/>
+    </tpm>
     <graphics type="vnc" port="-1"/>
     <watchdog model="ib700" action="pause"/>
     <memballoon model="virtio"/>
@@ -322,6 +325,9 @@
         <device path="/dev/tpm0"/>
       </backend>
     </tpm>
+    <tpm model="tpm-crb">
+      <backend type="emulator" version="2.0"/>
+    </tpm>
     <graphics type="vnc" port="-1"/>
     <watchdog model="ib700" action="pause"/>
     <memballoon model="virtio"/>

tests/clitest.py

@@ -450,6 +450,7 @@ cache.mode=emulate,cache.level=3 \
 --watchdog ib700,action=pause \
 --tpm passthrough,model=tpm-tis,path=/dev/tpm0 \
 --tpm passthrough,model=tpm-crb,path=/dev/tpm0 \
+--tpm emulator,model=tpm-crb,version=2.0 \
 --rng egd,backend_host=127.0.0.1,backend_service=8000,backend_type=udp,backend_mode=bind,backend_connect_host=foo,backend_connect_service=708 \
 --panic iobase=0x506 \
 """, "singleton-config-2")

virtinst/cli.py

@@ -2448,6 +2448,7 @@ _register_virt_parser(ParserTPM)
 _add_device_address_args(ParserTPM)
 ParserTPM.add_arg("type", "type")
 ParserTPM.add_arg("model", "model")
+ParserTPM.add_arg("version", "version")
 ParserTPM.add_arg("device_path", "path")
 
 

virtinst/devices/tpm.py

@@ -16,9 +16,15 @@ from ..xmlbuilder import XMLProperty
 class DeviceTpm(Device):
     XML_NAME = "tpm"
 
+    VERSION_1_2 = "1.2"
+    VERSION_2_0 = "2.0"
+    VERSION_DEFAULT = "default"
+    VERSIONS = [VERSION_1_2, VERSION_2_0]
+
     TYPE_PASSTHROUGH = "passthrough"
+    TYPE_EMULATOR = "emulator"
     TYPE_DEFAULT = "default"
-    TYPES = [TYPE_PASSTHROUGH]
+    TYPES = [TYPE_PASSTHROUGH, TYPE_EMULATOR]
 
     MODEL_TIS = "tpm-tis"
     MODEL_CRB = "tpm-crb"
@@ -29,6 +35,8 @@ class DeviceTpm(Device):
     def get_pretty_type(tpm_type):
         if tpm_type == DeviceTpm.TYPE_PASSTHROUGH:
             return _("Passthrough device")
+        if tpm_type == DeviceTpm.TYPE_EMULATOR:
+            return _("Emulated device")
         return tpm_type
 
     @staticmethod
@@ -45,6 +53,7 @@ class DeviceTpm(Device):
         """
         users = {
             "device_path": [self.TYPE_PASSTHROUGH],
+            "version": [self.TYPE_EMULATOR],
         }
 
         if users.get(propname):
@@ -54,7 +63,20 @@ class DeviceTpm(Device):
 
     type = XMLProperty("./backend/@type",
                        default_cb=lambda s: s.TYPE_PASSTHROUGH)
+
+    def _get_default_version(self):
+        if not self.supports_property("version"):
+            return None
+        return self.VERSION_1_2
+    version = XMLProperty("./backend/@version",
+                          default_cb=_get_default_version)
     model = XMLProperty("./@model",
                        default_cb=lambda s: s.MODEL_TIS)
+
+
+    def _get_default_device_path(self):
+        if not self.supports_property("device_path"):
+            return None
+        return "/dev/tpm0"
     device_path = XMLProperty("./backend/device/@path",
-                              default_cb=lambda s: "/dev/tpm0")
+                              default_cb=_get_default_device_path)