diff --git a/include/qapi/qobject-input-visitor.h b/include/qapi/qobject-input-visitor.h
index 282f9d25e4..b399285c43 100644
--- a/include/qapi/qobject-input-visitor.h
+++ b/include/qapi/qobject-input-visitor.h
@@ -68,4 +68,16 @@ Visitor *qobject_input_visitor_new(QObject *obj);
  */
 Visitor *qobject_input_visitor_new_keyval(QObject *obj);
 
+/*
+ * Create a QObject input visitor for parsing @str.
+ *
+ * If @str looks like JSON, parse it as JSON, else as KEY=VALUE,...
+ * @implied_key applies to KEY=VALUE, and works as in keyval_parse().
+ * On failure, store an error through @errp and return NULL.
+ * On success, return a new QObject input visitor for the parse.
+ */
+Visitor *qobject_input_visitor_new_str(const char *str,
+                                       const char *implied_key,
+                                       Error **errp);
+
 #endif
diff --git a/qapi/qobject-input-visitor.c b/qapi/qobject-input-visitor.c
index 6c5604089b..1a484d54be 100644
--- a/qapi/qobject-input-visitor.c
+++ b/qapi/qobject-input-visitor.c
@@ -18,9 +18,11 @@
 #include "qapi/visitor-impl.h"
 #include "qemu/queue.h"
 #include "qemu-common.h"
+#include "qapi/qmp/qjson.h"
 #include "qapi/qmp/types.h"
 #include "qapi/qmp/qerror.h"
 #include "qemu/cutils.h"
+#include "qemu/option.h"
 
 typedef struct StackObject {
     const char *name;            /* Name of @obj in its parent, if any */
@@ -656,3 +658,37 @@ Visitor *qobject_input_visitor_new_keyval(QObject *obj)
 
     return &v->visitor;
 }
+
+Visitor *qobject_input_visitor_new_str(const char *str,
+                                       const char *implied_key,
+                                       Error **errp)
+{
+    bool is_json = str[0] == '{';
+    QObject *obj;
+    QDict *args;
+    Visitor *v;
+
+    if (is_json) {
+        obj = qobject_from_json(str, errp);
+        if (!obj) {
+            /* Work around qobject_from_json() lossage TODO fix that */
+            if (errp && !*errp) {
+                error_setg(errp, "JSON parse error");
+                return NULL;
+            }
+            return NULL;
+        }
+        args = qobject_to_qdict(obj);
+        assert(args);
+        v = qobject_input_visitor_new(QOBJECT(args));
+    } else {
+        args = keyval_parse(str, implied_key, errp);
+        if (!args) {
+            return NULL;
+        }
+        v = qobject_input_visitor_new_keyval(QOBJECT(args));
+    }
+    QDECREF(args);
+
+    return v;
+}