Skip events from mixins when unnecessary

Mixins are loaded to other classes, which means that these events are
called on a varied number of qubes even when it is unnecessary.

Author: ben-grande

qubes/vm/mix/dvmtemplate.py

@@ -62,6 +62,8 @@ def on_domain_loaded(self, event) -> None:
         """
         # pylint: disable=unused-argument
         assert isinstance(self, qubes.vm.BaseVM)
+        if not getattr(self, "template_for_dispvms"):
+            return
         changes = False
         # Began preloading, host rebooted, autostart script didn't run yet.
         old_preload = self.get_feat_preload()
@@ -131,6 +133,8 @@ def __on_domain_pre_start(self, event, **kwargs) -> None:
     @qubes.events.handler("domain-remove-from-disk")
     async def on_dvmtemplate_remove_from_disk(self, event, **kwargs):
         # pylint: disable=unused-argument
+        if not getattr(self, "template_for_dispvms"):
+            return
         preloads = [disp for disp in self.dispvms if disp.is_preload]
         if not preloads:
             return
@@ -148,13 +152,17 @@ async def on_dvmtemplate_domain_shutdown(self, _event, **_kwargs) -> None:
         """
         Refresh preloaded disposables on shutdown.
         """
+        if not getattr(self, "template_for_dispvms"):
+            return
         self.refresh_outdated_preload()
 
     @qubes.events.handler("property-reset:*", "property-set:*")
     def on_dvmtemplate_property_changed(self, _event, name, **_kwargs) -> None:
         """
         Refresh preloaded disposables if property affects the disposable.
         """
+        if not getattr(self, "template_for_dispvms"):
+            return
         if name not in qubes.vm.dispvm.PRELOAD_OUTDATED_IGNORED_PROPERTIES:
             self.refresh_outdated_preload(delay=30)
 
@@ -407,6 +415,8 @@ def __on_pre_property_set_template(
                 property.
         """
         # pylint: disable=unused-argument
+        if not getattr(self, "template_for_dispvms"):
+            return
         if newvalue == oldvalue:
             return
         dependencies = [

qubes/vm/mix/net.py

@@ -294,6 +294,8 @@ def on_domain_load_netvm_loop_check(self, event):
         # pylint: disable=unused-argument
         # make sure there are no netvm loops - which could cause qubesd
         # looping infinitely
+        if not self.netvm:
+            return
         if self is self.netvm:
             self.log.error(
                 "vm '%s' network-connected to itself, breaking the "
@@ -338,6 +340,9 @@ async def on_domain_started_net(self, event, **kwargs):
         if self.netvm:
             self.netvm.reload_firewall_for_vm(self)  # pylint: disable=no-member
 
+        if not self.provides_network:
+            return
+
         for vm in self.connected_vms:
             if not vm.is_running() or vm.is_paused():
                 continue
@@ -409,6 +414,8 @@ def on_domain_pre_shutdown(self, event, force=False):
         If `force` is `True` tries to detach network interfaces of connected
         vms
         """  # pylint: disable=unused-argument
+        if not self.provides_network:
+            return
 
         connected_vms = [
             vm
@@ -741,6 +748,8 @@ def on_property_set_provides(self, _event, name, newvalue, oldvalue=None):
     def on_domain_qdb_create(self, event):
         """Fills the QubesDB with firewall entries."""
         # pylint: disable=unused-argument
+        if not self.provides_network:
+            return
 
         # Keep the following in sync with on_firewall_changed.
         self.reload_connected_ips()