Introduce three new flags to `ObjectPropertyFlags` to better manage property interactions with external users (CLI, QMP, HMP):
1. OBJ_PROP_FLAG_USER_SET: Marks a property as having been modified by an external user. This flag is designed to be "sticky": once set, it persists even if the property value is subsequently overwritten by internal logic. It allows the QEMU system to distinguish user intent. The advantage of this design is that it is not needed to manually clear the USER_SET flag on every internal write. This simplifies the logic and decouples flag management from the current property setting path (object_property_set()). This is chosen over a strict "current origin" approach (where internal writes would clear the flag) for a practical reason: QEMU code often modifies underlying struct fields (which are defined as properties) directly, bypassing the property API entirely. This makes it impossible to "accurately" track whether the *current* value truly comes from the user. Therefore, a sticky "user touched this" flag is the only meaningful and robust solution. 2. OBJ_PROP_FLAG_DEPRECATED: Marks a property as deprecated. 3. OBJ_PROP_FLAG_INTERNAL: Marks a property as internal-only, disallowing external user access. Additionally, update object_property_set_flags() to implement the enforcement logic. When a property is flagged with OBJ_PROP_FLAG_USER_SET: - If the property is also marked OBJ_PROP_FLAG_DEPRECATED, report a warning. - If the property is also marked OBJ_PROP_FLAG_INTERNAL, raise an error and stop the operation. Suggested-by: Igor Mammedov <[email protected]> Signed-off-by: Zhao Liu <[email protected]> --- include/qom/object.h | 24 ++++++++++++++++++++++++ qom/object.c | 15 +++++++++++++++ 2 files changed, 39 insertions(+) diff --git a/include/qom/object.h b/include/qom/object.h index 856b12e7289c..1b77429aa28b 100644 --- a/include/qom/object.h +++ b/include/qom/object.h @@ -109,6 +109,30 @@ typedef enum { * will automatically add a getter and a setter to this property. */ OBJ_PROP_FLAG_READWRITE = (OBJ_PROP_FLAG_READ | OBJ_PROP_FLAG_WRITE), + /* + * The property was explicitly set by an external user. + * + * This flag is set whenever the property is modified via external interfaces + * (CLI, QMP, HMP). It allows internal code to distinguish whether the + * property has been modified by the user. + * + * Once set, this flag persists even if the property value is subsequently + * overwritten by internal logic. It is NOT automatically cleared and must + * be explicitly cleared using object_property_clear_flags(). + */ + OBJ_PROP_FLAG_USER_SET = BIT(2), + /* + * The property is deprecated and will be removed in the future version. + * + * Any setting to this property by the user will raise a deprecation warning. + */ + OBJ_PROP_FLAG_DEPRECATED = BIT(3), + /* + * The property is internal only and cannot be set by the user. + * + * Any setting to this property by the user will raise an error. + */ + OBJ_PROP_FLAG_INTERNAL = BIT(4), } ObjectPropertyFlags; struct ObjectProperty diff --git a/qom/object.c b/qom/object.c index 49ef99a299b6..75a1fe7ea1d3 100644 --- a/qom/object.c +++ b/qom/object.c @@ -1242,6 +1242,21 @@ bool object_property_set_flags(Object *obj, const char *name, return false; } + if ((flags & OBJ_PROP_FLAG_USER_SET)) { + if (prop->flags & OBJ_PROP_FLAG_DEPRECATED) { + warn_report("Property '%s.%s' has been deprecated. " + "Please do not use it.", + object_get_typename(obj), name); + } + + if (prop->flags & OBJ_PROP_FLAG_INTERNAL) { + error_setg(errp, "Property '%s.%s' is internal only. " + "It can't be set by external user", + object_get_typename(obj), name); + return false; + } + } + prop->flags |= flags; return true; } -- 2.34.1
