From cbc94d9702882128c52b72b252b8eb775b0e73af Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Sun, 18 Jul 2021 08:50:44 +0200 Subject: [PATCH] qom: use correct field name when getting/setting alias properties Alias targets have a different name than the alias property itself (e.g. a machine's pflash0 might be an alias of a property named 'drive'). When the target's getter or setter invokes the visitor, it will use a different name than what the caller expects, and the visitor will not be able to find it (or will consume erroneously). The solution is for alias getters and setters to wrap the incoming visitor, and forward the sole field that the target is expecting while renaming it appropriately. This bug has been there forever, but it was exposed after -M parsing switched from QemuOptions and StringInputVisitor to keyval and QObjectInputVisitor. Before, the visitor ignored the name. Now, it checks "drive" against what was passed on the command line and finds that no such property exists. Fixes: https://gitlab.com/qemu-project/qemu/-/issues/484 Reported-by: Alex Williamson Signed-off-by: Paolo Bonzini --- qom/object.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/qom/object.c b/qom/object.c index 6a01d56546..e86cb05b84 100644 --- a/qom/object.c +++ b/qom/object.c @@ -20,6 +20,7 @@ #include "qapi/string-input-visitor.h" #include "qapi/string-output-visitor.h" #include "qapi/qobject-input-visitor.h" +#include "qapi/forward-visitor.h" #include "qapi/qapi-builtin-visit.h" #include "qapi/qmp/qerror.h" #include "qapi/qmp/qjson.h" @@ -2683,16 +2684,20 @@ static void property_get_alias(Object *obj, Visitor *v, const char *name, void *opaque, Error **errp) { AliasProperty *prop = opaque; + Visitor *alias_v = visitor_forward_field(v, prop->target_name, name); - object_property_get(prop->target_obj, prop->target_name, v, errp); + object_property_get(prop->target_obj, prop->target_name, alias_v, errp); + visit_free(alias_v); } static void property_set_alias(Object *obj, Visitor *v, const char *name, void *opaque, Error **errp) { AliasProperty *prop = opaque; + Visitor *alias_v = visitor_forward_field(v, prop->target_name, name); - object_property_set(prop->target_obj, prop->target_name, v, errp); + object_property_set(prop->target_obj, prop->target_name, alias_v, errp); + visit_free(alias_v); } static Object *property_resolve_alias(Object *obj, void *opaque,