CpuModelInfo member @props is semantically a mapping from name to
value, and syntactically a JSON object on the wire.  This translates
to QDict in C.  Since the QAPI schema language lacks the means to
express 'object', we use 'any' instead.  This is QObject in C.
Commands taking a CpuModelInfo argument need to check the QObject is a
QDict.

The i386 version of qmp_query_cpu_model_expansion() fails to check.
Instead, @props is silently ignored when it's not an object.  For
instance,

    {"execute": "query-cpu-model-expansion", "arguments": {"type": "full", "model": {"name": "qemu64", "props": null}}}

succeeds.

Fix by refactoring the code to match the other targets.  Now the
command fails as it should:

    {"error": {"class": "GenericError", "desc": "Invalid parameter type for 'props', expected: object"}}

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 target/i386/cpu-sysemu.c | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/target/i386/cpu-sysemu.c b/target/i386/cpu-sysemu.c
index 7422096737..df91f97827 100644
--- a/target/i386/cpu-sysemu.c
+++ b/target/i386/cpu-sysemu.c
@@ -25,6 +25,7 @@
 #include "qapi/error.h"
 #include "qapi/qapi-visit-run-state.h"
 #include "qapi/qmp/qdict.h"
+#include "qapi/qobject-input-visitor.h"
 #include "qom/qom-qobject.h"
 #include "qapi/qapi-commands-machine-target.h"
 #include "hw/qdev-properties.h"
@@ -129,20 +130,35 @@ static void x86_cpu_to_dict_full(X86CPU *cpu, QDict *props)
     }
 }
 
-static void object_apply_props(Object *obj, QDict *props, Error **errp)
+static void object_apply_props(Object *obj, QObject *props, Error **errp)
 {
+    Visitor *visitor;
+    QDict *qdict;
     const QDictEntry *prop;
 
-    for (prop = qdict_first(props); prop; prop = qdict_next(props, prop)) {
-        if (!object_property_set_qobject(obj, qdict_entry_key(prop),
-                                         qdict_entry_value(prop), errp)) {
-            break;
+    visitor = qobject_input_visitor_new(props);
+    if (!visit_start_struct(visitor, "props", NULL, 0, errp)) {
+        visit_free(visitor);
+        return;
+    }
+
+    qdict = qobject_to(QDict, props);
+    for (prop = qdict_first(qdict); prop; prop = qdict_next(qdict, prop)) {
+        if (!object_property_set(obj, qdict_entry_key(prop),
+                                 visitor, errp)) {
+            goto out;
         }
     }
+
+    visit_check_struct(visitor, errp);
+out:
+    visit_end_struct(visitor, NULL);
+    visit_free(visitor);
 }
 
 /* Create X86CPU object according to model+props specification */
-static X86CPU *x86_cpu_from_model(const char *model, QDict *props, Error **errp)
+static X86CPU *x86_cpu_from_model(const char *model, QObject *props,
+                                  Error **errp)
 {
     X86CPU *xc = NULL;
     X86CPUClass *xcc;
@@ -187,8 +203,7 @@ qmp_query_cpu_model_expansion(CpuModelExpansionType type,
     QDict *props = NULL;
     const char *base_name;
 
-    xc = x86_cpu_from_model(model->name, qobject_to(QDict, model->props),
-                            &err);
+    xc = x86_cpu_from_model(model->name, model->props, &err);
     if (err) {
         goto out;
     }
-- 
2.44.0