dom0/spec: fix HVM settings on upgrade

HVM should have meminfo-writer disabled by default (and now have). But existing
VMs have it already enabled so it must be fixed now. Generic HVM isn't capable
of dynamic memory management.

Previously it was forced to always have maxmem=memory but it wasn't fully
correct because someone could install Qubes agents/PV drivers including
meminfo-writer and xen-balloon even in HVM so it should be possible to turn it.

rpm_spec/core-dom0.spec

@@ -291,6 +291,25 @@ fi
 mkdir -p /var/lib/qubes/removed-udev-scripts
 mv -f /lib/udev/rules.d/69-xorg-vmmouse.rules /var/lib/qubes/removed-udev-scripts/ 2> /dev/null || :
 
+if [ "$1" -gt 1 ] ; then
+    # upgrade
+
+    # Fix HVM setting - meminfo-writer was erroneously enabled by default
+    cat << __EOF__ | python
+from qubes.qubes import QubesVmCollection
+qc = QubesVmCollection ()
+qc.lock_db_for_writing ()
+qc.load ()
+for vm in qc.values():
+    if vm.type == "HVM" and vm.memory == vm.maxmem:
+        vm.services['meminfo-writer'] = False
+
+qc.save()
+qc.unlock_db ()
+exit()
+__EOF__
+
+fi
 %clean
 rm -rf $RPM_BUILD_ROOT
 rm -f %{name}-%{version}