Commit e2fb3fbb authored by Markus Armbruster's avatar Markus Armbruster
Browse files

sysbus: Fix latent bug with onboard devices 



The first call of sysbus_get_default() creates the main system bus and
stores it in QOM as "/machine/unattached/sysbus".  This must not
happen before main() creates "/machine", or else container_get() would
"helpfully" create it as "container" object, and the real creation of
"/machine" would later abort with "attempt to add duplicate property
'machine' to object (type 'container')".  Has been that way ever since
we wired up busses in QOM (commit f968fc68, v1.2.0).

I believe the bug is latent.  I got it to bite by trying to
qdev_create() a sysbus device from a machine's .instance_init()
method.

The fix is obvious: store the main system bus in QOM right after
creating "/machine".

Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
Reviewed-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: default avatarThomas Huth <thuth@redhat.com>
Message-Id: <20190308131445.17502-5-armbru@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent fc4a4734

hw/core/sysbus.c

+0 −3
Original line number Diff line number Diff line
@@ -357,9 +357,6 @@ static void main_system_bus_create(void) 
    qbus_create_inplace(main_system_bus, system_bus_info.instance_size,

                        TYPE_SYSTEM_BUS, NULL, "main-system-bus");

    OBJECT(main_system_bus)->free = g_free;

    object_property_add_child(container_get(qdev_get_machine(),

                                            "/unattached"),

                              "sysbus", OBJECT(main_system_bus), NULL);

}



BusState *sysbus_get_default(void)

vl.c

+4 −0
Original line number Diff line number Diff line
@@ -3989,6 +3989,10 @@ int main(int argc, char **argv, char **envp) 
    }

    object_property_add_child(object_get_root(), "machine",

                              OBJECT(current_machine), &error_abort);

    object_property_add_child(container_get(OBJECT(current_machine),

                                            "/unattached"),

                              "sysbus", OBJECT(sysbus_get_default()),

                              NULL);



    if (machine_class->minimum_page_bits) {

        if (!set_preferred_target_page_bits(machine_class->minimum_page_bits)) {