[PULL 21/87] qom: introduce object_register_sugar_prop

[Paolo Bonzini <pbonzini@redhat.com>]

Similar to the existing "-rtc driftfix" option, we will convert some
legacy "-machine" command line options to global properties on accelerators.
Because accelerators are not devices, we cannot use qdev_prop_register_global.
Instead, provide a slot in the generic object_compat_props arrays for
command line syntactic sugar.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 include/qom/object.h |  1 +
 qom/object.c         | 23 +++++++++++++++++++++--
 vl.c                 | 10 +++-------
 3 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/include/qom/object.h b/include/qom/object.h
index 128d00c..230b18f 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -679,6 +679,7 @@ void object_apply_global_props(Object *obj, const GPtrArray *props,
                                Error **errp);
 void object_set_machine_compat_props(GPtrArray *compat_props);
 void object_set_accelerator_compat_props(GPtrArray *compat_props);
+void object_register_sugar_prop(const char *driver, const char *prop, const char *value);
 void object_apply_compat_props(Object *obj);
 
 /**
diff --git a/qom/object.c b/qom/object.c
index d51b57f..e7b72f7 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -414,10 +414,29 @@ void object_apply_global_props(Object *obj, const GPtrArray *props, Error **errp
  * Global property defaults
  * Slot 0: accelerator's global property defaults
  * Slot 1: machine's global property defaults
+ * Slot 2: global properties from legacy command line option
  * Each is a GPtrArray of of GlobalProperty.
  * Applied in order, later entries override earlier ones.
  */
-static GPtrArray *object_compat_props[2];
+static GPtrArray *object_compat_props[3];
+
+/*
+ * Retrieve @GPtrArray for global property defined with options
+ * other than "-global".  These are generally used for syntactic
+ * sugar and legacy command line options.
+ */
+void object_register_sugar_prop(const char *driver, const char *prop, const char *value)
+{
+    GlobalProperty *g;
+    if (!object_compat_props[2]) {
+        object_compat_props[2] = g_ptr_array_new();
+    }
+    g = g_new0(GlobalProperty, 1);
+    g->driver = g_strdup(driver);
+    g->property = g_strdup(prop);
+    g->value = g_strdup(value);
+    g_ptr_array_add(object_compat_props[2], g);
+}
 
 /*
  * Set machine's global property defaults to @compat_props.
@@ -445,7 +464,7 @@ void object_apply_compat_props(Object *obj)
 
     for (i = 0; i < ARRAY_SIZE(object_compat_props); i++) {
         object_apply_global_props(obj, object_compat_props[i],
-                                  &error_abort);
+                                  i == 2 ? &error_fatal : &error_abort);
     }
 }
 
diff --git a/vl.c b/vl.c
index c350eef..b95c161 100644
--- a/vl.c
+++ b/vl.c
@@ -895,13 +895,9 @@ static void configure_rtc(QemuOpts *opts)
     value = qemu_opt_get(opts, "driftfix");
     if (value) {
         if (!strcmp(value, "slew")) {
-            static GlobalProperty slew_lost_ticks = {
-                .driver   = "mc146818rtc",
-                .property = "lost_tick_policy",
-                .value    = "slew",
-            };
-
-            qdev_prop_register_global(&slew_lost_ticks);
+            object_register_sugar_prop("mc146818rtc",
+                                       "lost_tick_policy",
+                                       "slew");
         } else if (!strcmp(value, "none")) {
             /* discard is default */
         } else {
-- 
1.8.3.1