Re: [PATCH v2 08/13] qdev: Make qdev_get_machine() not use container_get()

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 21/11/24 20:21, Peter Xu wrote:
> Currently, qdev_get_machine() has a slight misuse on container_get(), as
> the helper says "get a container" but in reality the goal is to get the
> machine object.  It is still a "container" but not strictly.
> 
> Note that it _may_ get a container (at "/machine") in our current unit test
> of test-qdev-global-props.c before all these changes, but it's probably
> unexpected and worked by accident.
> 
> Switch to an explicit object_resolve_path_component(), with a side benefit
> that qdev_get_machine() can happen a lot, and we don't need to split the
> string ("/machine") every time.  This also paves way for making the helper
> container_get() never try to return a non-container at all.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>   hw/core/qdev.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index 5f13111b77..b622be15ee 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -817,7 +817,12 @@ Object *qdev_get_machine(void)
>       static Object *dev;
>   
>       if (dev == NULL) {
> -        dev = container_get(object_get_root(), "/machine");
> +        dev = object_resolve_path_component(object_get_root(), "machine");
> +        /*
> +         * Any call to this function before machine is created is treated
> +         * as a programming error as of now.
> +         */
> +        assert(dev);

This fails for user-emulation:

./qemu-x86_64 /bin/echo foo
qemu-x86_64: ../../hw/core/qdev.c:825: qdev_get_machine: Assertion `dev' 
failed.
Aborted (core dumped)

We need to skip this test for user emulation, but this file is in
hwcore_ss[] so the CONFIG_USER_ONLY definitions is not available.

Any simple enough idea to not block this?

>       }
>   
>       return dev;