query-cpu-model-expansion takes a CpuModelInfo argument.  The
loongarch version of the command silently ignores the argument's
member @props.  For instance,

    {"execute": "query-cpu-model-expansion", "arguments": {"type": "static", "model": {"name": "la464", "props": null}}}

and

    {"execute": "query-cpu-model-expansion", "arguments": {"type": "static", "model": {"name": "la464", "props": {"prop": null}}}}

succeed.

Add skeleton code for property processing that recognizes no
properties.  Now the two commands fail as they should:

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

and

    {"error": {"class": "GenericError", "desc": "Parameter 'model.props.prop' is unexpected"}}

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 target/loongarch/loongarch-qmp-cmds.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/target/loongarch/loongarch-qmp-cmds.c b/target/loongarch/loongarch-qmp-cmds.c
index ec33ce81f0..44d1f089b6 100644
--- a/target/loongarch/loongarch-qmp-cmds.c
+++ b/target/loongarch/loongarch-qmp-cmds.c
@@ -48,6 +48,8 @@ CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType type,
                                                      CpuModelInfo *model,
                                                      Error **errp)
 {
+    Visitor *visitor;
+    bool ok;
     CpuModelExpansionInfo *expansion_info;
     QDict *qdict_out;
     ObjectClass *oc;
@@ -60,6 +62,21 @@ CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType type,
         return NULL;
     }
 
+    if (model->props) {
+        visitor = qobject_input_visitor_new(model->props);
+        if (!visit_start_struct(visitor, "model.props", NULL, 0, errp)) {
+            visit_free(visitor);
+            return NULL;
+        }
+
+        ok = visit_check_struct(visitor, errp);
+        visit_end_struct(visitor, NULL);
+        visit_free(visitor);
+        if (!ok) {
+            return NULL;
+        }
+    }
+
     oc = cpu_class_by_name(TYPE_LOONGARCH_CPU, model->name);
     if (!oc) {
         error_setg(errp, "The CPU type '%s' is not a recognized LoongArch CPU type",
-- 
2.44.0