qom: simplify object_find_property / object_class_find_property

When debugging QEMU it is often useful to put a breakpoint on the
error_setg_internal method impl.

Unfortunately the object_property_add / object_class_property_add
methods call object_property_find / object_class_property_find methods
to check if a property exists already before adding the new property.

As a result there are a huge number of calls to error_setg_internal
on startup of most QEMU commands, making it very painful to set a
breakpoint on this method.

Most callers of object_find_property and object_class_find_property,
however, pass in a NULL for the Error parameter. This simplifies the
methods to remove the Error parameter entirely, and then adds some
new wrapper methods that are able to raise an Error when needed.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200914135617.1493072-1-berrange@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

hw/arm/armv7m.c

@@ -169,28 +169,28 @@ static void armv7m_realize(DeviceState *dev, Error **errp)
 
     object_property_set_link(OBJECT(s->cpu), "memory", OBJECT(&s->container),
                              &error_abort);
-    if (object_property_find(OBJECT(s->cpu), "idau", NULL)) {
+    if (object_property_find(OBJECT(s->cpu), "idau")) {
         object_property_set_link(OBJECT(s->cpu), "idau", s->idau,
                                  &error_abort);
     }
-    if (object_property_find(OBJECT(s->cpu), "init-svtor", NULL)) {
+    if (object_property_find(OBJECT(s->cpu), "init-svtor")) {
         if (!object_property_set_uint(OBJECT(s->cpu), "init-svtor",
                                       s->init_svtor, errp)) {
             return;
         }
     }
-    if (object_property_find(OBJECT(s->cpu), "start-powered-off", NULL)) {
+    if (object_property_find(OBJECT(s->cpu), "start-powered-off")) {
         if (!object_property_set_bool(OBJECT(s->cpu), "start-powered-off",
                                       s->start_powered_off, errp)) {
             return;
         }
     }
-    if (object_property_find(OBJECT(s->cpu), "vfp", NULL)) {
+    if (object_property_find(OBJECT(s->cpu), "vfp")) {
         if (!object_property_set_bool(OBJECT(s->cpu), "vfp", s->vfp, errp)) {
             return;
         }
     }
-    if (object_property_find(OBJECT(s->cpu), "dsp", NULL)) {
+    if (object_property_find(OBJECT(s->cpu), "dsp")) {
         if (!object_property_set_bool(OBJECT(s->cpu), "dsp", s->dsp, errp)) {
             return;
         }

hw/arm/exynos4210.c

@@ -214,7 +214,7 @@ static void exynos4210_realize(DeviceState *socdev, Error **errp)
         /* By default A9 CPUs have EL3 enabled.  This board does not currently
          * support EL3 so the CPU EL3 property is disabled before realization.
          */
-        if (object_property_find(cpuobj, "has_el3", NULL)) {
+        if (object_property_find(cpuobj, "has_el3")) {
             object_property_set_bool(cpuobj, "has_el3", false, &error_fatal);
         }
 

hw/arm/highbank.c

@@ -276,7 +276,7 @@ static void calxeda_init(MachineState *machine, enum cxmachines machine_id)
                                      &error_abort);
         }
 
-        if (object_property_find(cpuobj, "reset-cbar", NULL)) {
+        if (object_property_find(cpuobj, "reset-cbar")) {
             object_property_set_int(cpuobj, "reset-cbar", MPCORE_PERIPHBASE,
                                     &error_abort);
         }

hw/arm/integratorcp.c

@@ -603,7 +603,7 @@ static void integratorcp_init(MachineState *machine)
      * currently support EL3 so the CPU EL3 property is disabled before
      * realization.
      */
-    if (object_property_find(cpuobj, "has_el3", NULL)) {
+    if (object_property_find(cpuobj, "has_el3")) {
         object_property_set_bool(cpuobj, "has_el3", false, &error_fatal);
     }
 

hw/arm/realview.c

@@ -108,7 +108,7 @@ static void realview_init(MachineState *machine,
          * does not currently support EL3 so the CPU EL3 property is disabled
          * before realization.
          */
-        if (object_property_find(cpuobj, "has_el3", NULL)) {
+        if (object_property_find(cpuobj, "has_el3")) {
             object_property_set_bool(cpuobj, "has_el3", false, &error_fatal);
         }
 

hw/arm/sbsa-ref.c

@@ -703,7 +703,7 @@ static void sbsa_ref_init(MachineState *machine)
         numa_cpu_pre_plug(&possible_cpus->cpus[cs->cpu_index], DEVICE(cpuobj),
                           &error_fatal);
 
-        if (object_property_find(cpuobj, "reset-cbar", NULL)) {
+        if (object_property_find(cpuobj, "reset-cbar")) {
             object_property_set_int(cpuobj, "reset-cbar",
                                     sbsa_ref_memmap[SBSA_CPUPERIPHS].base,
                                     &error_abort);

hw/arm/versatilepb.c

@@ -213,7 +213,7 @@ static void versatile_init(MachineState *machine, int board_id)
      * currently support EL3 so the CPU EL3 property is disabled before
      * realization.
      */
-    if (object_property_find(cpuobj, "has_el3", NULL)) {
+    if (object_property_find(cpuobj, "has_el3")) {
         object_property_set_bool(cpuobj, "has_el3", false, &error_fatal);
     }
 

hw/arm/vexpress.c

@@ -218,12 +218,12 @@ static void init_cpus(MachineState *ms, const char *cpu_type,
             object_property_set_bool(cpuobj, "has_el3", false, NULL);
         }
         if (!virt) {
-            if (object_property_find(cpuobj, "has_el2", NULL)) {
+            if (object_property_find(cpuobj, "has_el2")) {
                 object_property_set_bool(cpuobj, "has_el2", false, NULL);
             }
         }
 
-        if (object_property_find(cpuobj, "reset-cbar", NULL)) {
+        if (object_property_find(cpuobj, "reset-cbar")) {
             object_property_set_int(cpuobj, "reset-cbar", periphbase,
                                     &error_abort);
         }

hw/arm/virt.c

@@ -1806,7 +1806,7 @@ static void machvirt_init(MachineState *machine)
             object_property_set_bool(cpuobj, "has_el3", false, NULL);
         }
 
-        if (!vms->virt && object_property_find(cpuobj, "has_el2", NULL)) {
+        if (!vms->virt && object_property_find(cpuobj, "has_el2")) {
             object_property_set_bool(cpuobj, "has_el2", false, NULL);
         }
 
@@ -1822,15 +1822,15 @@ static void machvirt_init(MachineState *machine)
         }
 
         if (vmc->kvm_no_adjvtime &&
-            object_property_find(cpuobj, "kvm-no-adjvtime", NULL)) {
+            object_property_find(cpuobj, "kvm-no-adjvtime")) {
             object_property_set_bool(cpuobj, "kvm-no-adjvtime", true, NULL);
         }
 
-        if (vmc->no_pmu && object_property_find(cpuobj, "pmu", NULL)) {
+        if (vmc->no_pmu && object_property_find(cpuobj, "pmu")) {
             object_property_set_bool(cpuobj, "pmu", false, NULL);
         }
 
-        if (object_property_find(cpuobj, "reset-cbar", NULL)) {
+        if (object_property_find(cpuobj, "reset-cbar")) {
             object_property_set_int(cpuobj, "reset-cbar",
                                     vms->memmap[VIRT_CPUPERIPHS].base,
                                     &error_abort);
@@ -1850,7 +1850,7 @@ static void machvirt_init(MachineState *machine)
                  * The property exists only if MemTag is supported.
                  * If it is, we must allocate the ram to back that up.
                  */
-                if (!object_property_find(cpuobj, "tag-memory", NULL)) {
+                if (!object_property_find(cpuobj, "tag-memory")) {
                     error_report("MTE requested, but not supported "
                                  "by the guest CPU");
                     exit(1);

hw/arm/xilinx_zynq.c

@@ -196,7 +196,7 @@ static void zynq_init(MachineState *machine)
      * currently support EL3 so the CPU EL3 property is disabled before
      * realization.
      */
-    if (object_property_find(OBJECT(cpu), "has_el3", NULL)) {
+    if (object_property_find(OBJECT(cpu), "has_el3")) {
         object_property_set_bool(OBJECT(cpu), "has_el3", false, &error_fatal);
     }
 

hw/core/qdev-properties-system.c

@@ -460,7 +460,7 @@ void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd)
         qdev_prop_set_netdev(dev, "netdev", nd->netdev);
     }
     if (nd->nvectors != DEV_NVECTORS_UNSPECIFIED &&
-        object_property_find(OBJECT(dev), "vectors", NULL)) {
+        object_property_find(OBJECT(dev), "vectors")) {
         qdev_prop_set_uint32(dev, "vectors", nd->nvectors);
     }
     nd->instantiated = 1;

hw/core/sysbus.c

@@ -93,7 +93,7 @@ bool sysbus_has_irq(SysBusDevice *dev, int n)
     char *prop = g_strdup_printf("%s[%d]", SYSBUS_DEVICE_GPIO_IRQ, n);
     ObjectProperty *r;
 
-    r = object_property_find(OBJECT(dev), prop, NULL);
+    r = object_property_find(OBJECT(dev), prop);
     g_free(prop);
 
     return (r != NULL);

hw/cpu/a15mpcore.c

@@ -66,11 +66,11 @@ static void a15mp_priv_realize(DeviceState *dev, Error **errp)
          * either all the CPUs have TZ, or none do.
          */
         cpuobj = OBJECT(qemu_get_cpu(0));
-        has_el3 = object_property_find(cpuobj, "has_el3", NULL) &&
+        has_el3 = object_property_find(cpuobj, "has_el3") &&
             object_property_get_bool(cpuobj, "has_el3", &error_abort);
         qdev_prop_set_bit(gicdev, "has-security-extensions", has_el3);
         /* Similarly for virtualization support */
-        has_el2 = object_property_find(cpuobj, "has_el2", NULL) &&
+        has_el2 = object_property_find(cpuobj, "has_el2") &&
             object_property_get_bool(cpuobj, "has_el2", &error_abort);
         qdev_prop_set_bit(gicdev, "has-virtualization-extensions", has_el2);
     }

hw/cpu/a9mpcore.c

@@ -81,7 +81,7 @@ static void a9mp_priv_realize(DeviceState *dev, Error **errp)
     /* Make the GIC's TZ support match the CPUs. We assume that
      * either all the CPUs have TZ, or none do.
      */
-    has_el3 = object_property_find(cpuobj, "has_el3", NULL) &&
+    has_el3 = object_property_find(cpuobj, "has_el3") &&
         object_property_get_bool(cpuobj, "has_el3", &error_abort);
     qdev_prop_set_bit(gicdev, "has-security-extensions", has_el3);
 

hw/misc/iotkit-sysctl.c

@@ -83,7 +83,7 @@ static void set_init_vtor(uint64_t cpuid, uint32_t vtor)
     Object *cpuobj = OBJECT(arm_get_cpu_by_id(cpuid));
 
     if (cpuobj) {
-        if (object_property_find(cpuobj, "init-svtor", NULL)) {
+        if (object_property_find(cpuobj, "init-svtor")) {
             object_property_set_uint(cpuobj, "init-svtor", vtor, &error_abort);
         }
     }

hw/pci/pci.c

@@ -1900,7 +1900,7 @@ PCIDevice *pci_nic_init_nofail(NICInfo *nd, PCIBus *rootbus,
              * a temporary instance here to be able to check it.
              */
             Object *obj = object_new_with_class(OBJECT_CLASS(dc));
-            if (object_property_find(obj, "netdev", NULL)) {
+            if (object_property_find(obj, "netdev")) {
                 g_ptr_array_add(pci_nic_models, (gpointer)name);
             }
             object_unref(obj);

hw/scsi/scsi-bus.c

@@ -270,10 +270,10 @@ SCSIDevice *scsi_bus_legacy_add_drive(SCSIBus *bus, BlockBackend *blk,
         object_property_set_int(OBJECT(dev), "bootindex", bootindex,
                                 &error_abort);
     }
-    if (object_property_find(OBJECT(dev), "removable", NULL)) {
+    if (object_property_find(OBJECT(dev), "removable")) {
         qdev_prop_set_bit(dev, "removable", removable);
     }
-    if (serial && object_property_find(OBJECT(dev), "serial", NULL)) {
+    if (serial && object_property_find(OBJECT(dev), "serial")) {
         qdev_prop_set_string(dev, "serial", serial);
     }
     if (!qdev_prop_set_drive_err(dev, "drive", blk, errp)) {

include/qom/object.h

@@ -1463,14 +1463,52 @@ void object_property_set_default_uint(ObjectProperty *prop, uint64_t value);
  * object_property_find:
  * @obj: the object
  * @name: the name of the property
+ *
+ * Look up a property for an object.
+ *
+ * Return its #ObjectProperty if found, or NULL.
+ */
+ObjectProperty *object_property_find(Object *obj, const char *name);
+
+/**
+ * object_property_find_err:
+ * @obj: the object
+ * @name: the name of the property
  * @errp: returns an error if this function fails
  *
- * Look up a property for an object and return its #ObjectProperty if found.
+ * Look up a property for an object.
+ *
+ * Return its #ObjectProperty if found, or NULL.
  */
-ObjectProperty *object_property_find(Object *obj, const char *name,
-                                     Error **errp);
-ObjectProperty *object_class_property_find(ObjectClass *klass, const char *name,
-                                           Error **errp);
+ObjectProperty *object_property_find_err(Object *obj,
+                                         const char *name,
+                                         Error **errp);
+
+/**
+ * object_class_property_find:
+ * @klass: the object class
+ * @name: the name of the property
+ *
+ * Look up a property for an object class.
+ *
+ * Return its #ObjectProperty if found, or NULL.
+ */
+ObjectProperty *object_class_property_find(ObjectClass *klass,
+                                           const char *name);
+
+/**
+ * object_class_property_find_err:
+ * @klass: the object class
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Look up a property for an object class.
+ *
+ * Return its #ObjectProperty if found, or NULL.
+ */
+ObjectProperty *object_class_property_find_err(ObjectClass *klass,
+                                               const char *name,
+                                               Error **errp);
 
 typedef struct ObjectPropertyIterator {
     ObjectClass *nextclass;

qom/object.c

@@ -403,7 +403,7 @@ bool object_apply_global_props(Object *obj, const GPtrArray *props,
         if (object_dynamic_cast(obj, p->driver) == NULL) {
             continue;
         }
-        if (p->optional && !object_property_find(obj, p->property, NULL)) {
+        if (p->optional && !object_property_find(obj, p->property)) {
             continue;
         }
         p->used = true;
@@ -1214,7 +1214,7 @@ object_property_try_add(Object *obj, const char *name, const char *type,
         return ret;
     }
 
-    if (object_property_find(obj, name, NULL) != NULL) {
+    if (object_property_find(obj, name) != NULL) {
         error_setg(errp, "attempt to add duplicate property '%s' to object (type '%s')",
                    name, object_get_typename(obj));
         return NULL;
@@ -1256,7 +1256,7 @@ object_class_property_add(ObjectClass *klass,
 {
     ObjectProperty *prop;
 
-    assert(!object_class_property_find(klass, name, NULL));
+    assert(!object_class_property_find(klass, name));
 
     prop = g_malloc0(sizeof(*prop));
 
@@ -1273,24 +1273,27 @@ object_class_property_add(ObjectClass *klass,
     return prop;
 }
 
-ObjectProperty *object_property_find(Object *obj, const char *name,
-                                     Error **errp)
+ObjectProperty *object_property_find(Object *obj, const char *name)
 {
     ObjectProperty *prop;
     ObjectClass *klass = object_get_class(obj);
 
-    prop = object_class_property_find(klass, name, NULL);
+    prop = object_class_property_find(klass, name);
     if (prop) {
         return prop;
     }
 
-    prop = g_hash_table_lookup(obj->properties, name);
-    if (prop) {
-        return prop;
-    }
+    return g_hash_table_lookup(obj->properties, name);
+}
 
-    error_setg(errp, "Property '.%s' not found", name);
-    return NULL;
+ObjectProperty *object_property_find_err(Object *obj, const char *name,
+                                         Error **errp)
+{
+    ObjectProperty *prop = object_property_find(obj, name);
+    if (!prop) {
+        error_setg(errp, "Property '.%s' not found", name);
+    }
+    return prop;
 }
 
 void object_property_iter_init(ObjectPropertyIterator *iter,
@@ -1320,27 +1323,34 @@ void object_class_property_iter_init(ObjectPropertyIterator *iter,
     iter->nextclass = object_class_get_parent(klass);
 }
 
-ObjectProperty *object_class_property_find(ObjectClass *klass, const char *name,
-                                           Error **errp)
+ObjectProperty *object_class_property_find(ObjectClass *klass, const char *name)
 {
-    ObjectProperty *prop;
     ObjectClass *parent_klass;
 
     parent_klass = object_class_get_parent(klass);
     if (parent_klass) {
-        prop = object_class_property_find(parent_klass, name, NULL);
+        ObjectProperty *prop =
+            object_class_property_find(parent_klass, name);
         if (prop) {
             return prop;
         }
     }
 
-    prop = g_hash_table_lookup(klass->properties, name);
+    return g_hash_table_lookup(klass->properties, name);
+}
+
+ObjectProperty *object_class_property_find_err(ObjectClass *klass,
+                                               const char *name,
+                                               Error **errp)
+{
+    ObjectProperty *prop = object_class_property_find(klass, name);
     if (!prop) {
         error_setg(errp, "Property '.%s' not found", name);
     }
     return prop;
 }
 
+
 void object_property_del(Object *obj, const char *name)
 {
     ObjectProperty *prop = g_hash_table_lookup(obj->properties, name);
@@ -1355,7 +1365,7 @@ bool object_property_get(Object *obj, const char *name, Visitor *v,
                          Error **errp)
 {
     Error *err = NULL;
-    ObjectProperty *prop = object_property_find(obj, name, errp);
+    ObjectProperty *prop = object_property_find_err(obj, name, errp);
 
     if (prop == NULL) {
         return false;
@@ -1374,7 +1384,7 @@ bool object_property_set(Object *obj, const char *name, Visitor *v,
                          Error **errp)
 {
     Error *err = NULL;
-    ObjectProperty *prop = object_property_find(obj, name, errp);
+    ObjectProperty *prop = object_property_find_err(obj, name, errp);
 
     if (prop == NULL) {
         return false;
@@ -1590,7 +1600,7 @@ int object_property_get_enum(Object *obj, const char *name,
 {
     char *str;
     int ret;
-    ObjectProperty *prop = object_property_find(obj, name, errp);
+    ObjectProperty *prop = object_property_find_err(obj, name, errp);
     EnumProperty *enumprop;
 
     if (prop == NULL) {
@@ -1647,7 +1657,7 @@ out:
 
 const char *object_property_get_type(Object *obj, const char *name, Error **errp)
 {
-    ObjectProperty *prop = object_property_find(obj, name, errp);
+    ObjectProperty *prop = object_property_find_err(obj, name, errp);
     if (prop == NULL) {
         return NULL;
     }
@@ -2025,7 +2035,7 @@ char *object_get_canonical_path(const Object *obj)
 
 Object *object_resolve_path_component(Object *parent, const char *part)
 {
-    ObjectProperty *prop = object_property_find(parent, part, NULL);
+    ObjectProperty *prop = object_property_find(parent, part);
     if (prop == NULL) {
         return NULL;
     }
@@ -2724,8 +2734,8 @@ object_property_add_alias(Object *obj, const char *name,
     ObjectProperty *target_prop;
     g_autofree char *prop_type = NULL;
 
-    target_prop = object_property_find(target_obj, target_name,
-                                       &error_abort);
+    target_prop = object_property_find_err(target_obj, target_name,
+                                           &error_abort);
 
     if (object_property_is_child(target_prop)) {
         prop_type = g_strdup_printf("link%s",
@@ -2758,7 +2768,7 @@ void object_property_set_description(Object *obj, const char *name,
 {
     ObjectProperty *op;
 
-    op = object_property_find(obj, name, &error_abort);
+    op = object_property_find_err(obj, name, &error_abort);
     g_free(op->description);
     op->description = g_strdup(description);
 }

target/arm/monitor.c

@@ -214,7 +214,7 @@ CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType type,
 
     i = 0;
     while ((name = cpu_model_advertised_features[i++]) != NULL) {
-        ObjectProperty *prop = object_property_find(obj, name, NULL);
+        ObjectProperty *prop = object_property_find(obj, name);
         if (prop) {
             QObject *value;
 

target/i386/cpu.c

@@ -6828,7 +6828,7 @@ static void x86_cpu_register_bit_prop(X86CPU *cpu,
     ObjectProperty *op;
     uint64_t mask = (1ULL << bitnr);
 
-    op = object_property_find(OBJECT(cpu), prop_name, NULL);
+    op = object_property_find(OBJECT(cpu), prop_name);
     if (op) {
         fp = op->opaque;
         assert(fp->w == w);

target/ppc/translate_init.c.inc

@@ -10478,7 +10478,7 @@ static void ppc_cpu_parse_featurestr(const char *type, char *features,
         return;
     }
 
-    if (object_property_find(machine, "max-cpu-compat", NULL)) {
+    if (object_property_find(machine, "max-cpu-compat")) {
         int i;
         char **inpieces;
         char *s = features;