RE: [PATCH] qom/object_interfaces: Handle `len-` property first

[Lu Gao <Lu.Gao@verisilicon.com>]

ping

https://patchew.org/QEMU/20230921141634.26233-1-lu.gao@verisilicon.com/

Could you please help review the patch?

Thanks.
B.R.

-----Original Message-----
From: Lu Gao 
Sent: Thursday, September 21, 2023 10:17 PM
To: qemu-devel@nongnu.org
Cc: Lu Gao; Jianxian Wen; Paolo Bonzini; Daniel P. Berrangé; Eduardo Habkost
Subject: [PATCH] qom/object_interfaces: Handle `len-` property first

From: "Gao, Lu" <lu.gao@verisilicon.com>

Array property needs corresponding `len-` property set first to add
actual array properties. Then we need to make sure `len-` property is
set first before array property.

But when the model is used with like
`-device driver[,prop[=value][,...]]`
in QEMU command line options, this is not guaranteed in current
property set from qdict. Array property might be
handled before 'len-' property, then leads to an error.

Signed-off-by: Lu Gao <lu.gao@verisilicon.com>
Signed-off-by: Jianxian Wen <jianxian.wen@verisilicon.com>
---
 qom/object_interfaces.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c
index 7d31589b04..87500401a4 100644
--- a/qom/object_interfaces.c
+++ b/qom/object_interfaces.c
@@ -18,6 +18,7 @@
 #include "qapi/opts-visitor.h"
 #include "qemu/config-file.h"
 #include "qemu/keyval.h"
+#include "hw/qdev-properties.h"
 
 bool user_creatable_complete(UserCreatable *uc, Error **errp)
 {
@@ -52,8 +53,22 @@ static void object_set_properties_from_qdict(Object *obj, const QDict *qdict,
         return;
     }
     for (e = qdict_first(qdict); e; e = qdict_next(qdict, e)) {
-        if (!object_property_set(obj, e->key, v, errp)) {
-            goto out;
+        /* set "len-" first for the array props to be allocated first */
+        if (strncmp(e->key, PROP_ARRAY_LEN_PREFIX,
+                    strlen(PROP_ARRAY_LEN_PREFIX)) == 0) {
+            if (!object_property_set(obj, e->key, v, errp)) {
+                goto out;
+            }
+        }
+    }
+
+    for (e = qdict_first(qdict); e; e = qdict_next(qdict, e)) {
+        /* "len-" has been set above */
+        if (strncmp(e->key, PROP_ARRAY_LEN_PREFIX,
+                    strlen(PROP_ARRAY_LEN_PREFIX)) != 0) {
+            if (!object_property_set(obj, e->key, v, errp)) {
+                goto out;
+            }
         }
     }
     visit_check_struct(v, errp);
-- 
2.17.1