On Mon, Jun 19, 2017 at 01:59:07PM +0100, Mark Cave-Ayland wrote:
> In preparation for calling fw_cfg_init1() during realize rather than during
> init, move the assert() checking for existing fw_cfg devices and the linking
> of the device to the machine with object_property_add_child() to a new
> fw_cfg instance_init() function.
>
> This guarantees that we will still assert() correctly if more than one fw_cfg
> device is instantiated by accident.
>
> Signed-off-by: Mark Cave-Ayland <[email protected]>
> Reviewed-by: Laszlo Ersek <[email protected]>
> Tested-by: Laszlo Ersek <[email protected]>
> ---
> hw/nvram/fw_cfg.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
> index 99bdbc2..af45012 100644
> --- a/hw/nvram/fw_cfg.c
> +++ b/hw/nvram/fw_cfg.c
> @@ -915,10 +915,6 @@ static void fw_cfg_init1(DeviceState *dev)
> MachineState *machine = MACHINE(qdev_get_machine());
> uint32_t version = FW_CFG_VERSION;
>
> - assert(!object_resolve_path(FW_CFG_PATH, NULL));
> -
> - object_property_add_child(OBJECT(machine), FW_CFG_NAME, OBJECT(s), NULL);
> -
> qdev_init_nofail(dev);
>
> fw_cfg_add_bytes(s, FW_CFG_SIGNATURE, (char *)"QEMU", 4);
> @@ -1020,6 +1016,15 @@ FWCfgState *fw_cfg_find(void)
> return FW_CFG(object_resolve_path(FW_CFG_PATH, NULL));
> }
>
> +static void fw_cfg_init(Object *obj)
> +{
> + MachineState *machine = MACHINE(qdev_get_machine());
> +
> + assert(!object_resolve_path(FW_CFG_PATH, NULL));
> +
> + object_property_add_child(OBJECT(machine), FW_CFG_NAME, obj, NULL);
I don't think this belongs to instance_init. We must always be
able to instantiate objects without crashing QEMU or affecting
QEMU global state. This patch makes device-list-properties
crash:
$ qemu-system-x86_64 -display none -qmp unix:/tmp/qmp,server,nowait &
[1] 2848
$ echo 'device-list-properties typename=fw_cfg_mem' | ./scripts/qmp/qmp-shell
/tmp/qmp
Welcome to the QMP low-level shell!
Connected to QEMU 2.9.50
qemu-system-x86_64: qemu/hw/nvram/fw_cfg.c:974: fw_cfg_init: Assertion
`!object_resolve_path(FW_CFG_PATH, NULL)' failed.
(QEMU) Disconnected
[1]+ Aborted (core dumped) qemu-system-x86_64 -display none
-qmp unix:/tmp/qmp,server,nowait
$
I suggest moving this check to realize, like the rest of
fw_cfg_init1(), but change it to do proper error reporting
instead of asserting.
> +}
> +
> static void fw_cfg_class_init(ObjectClass *klass, void *data)
> {
> DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -1033,6 +1038,7 @@ static const TypeInfo fw_cfg_info = {
> .parent = TYPE_SYS_BUS_DEVICE,
> .abstract = true,
> .instance_size = sizeof(FWCfgState),
> + .instance_init = fw_cfg_init,
> .class_init = fw_cfg_class_init,
> };
>
> --
> 1.7.10.4
>
--
Eduardo
