Re: [PATCH v2 07/13] qom: Create system containers explicitly

[Philippe Mathieu-Daudé]

On 21/11/24 20:21, Peter Xu wrote:
> Always explicitly create QEMU system containers upfront.
>
> Root containers will be created when trying to fetch the root object the
> 1st time.  They are:
>
>    /objects
>    /chardevs
>    /backend
>
> Machine sub-containers will be created only until machine is being
> initialized.  They are:
>
>    /machine/unattached
>    /machine/peripheral
>    /machine/peripheral-anon
>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>   hw/core/machine.c |  3 ---
>   qom/object.c      | 24 +++++++++++++++++++++++-
>   system/vl.c       | 16 ++++++++++++++++
>   3 files changed, 39 insertions(+), 4 deletions(-)
>
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index a35c4a8fae..a72c001c3d 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -1198,9 +1198,6 @@ static void machine_initfn(Object *obj)
>       MachineState *ms = MACHINE(obj);
>       MachineClass *mc = MACHINE_GET_CLASS(obj);
>   
> -    container_get(obj, "/peripheral");
> -    container_get(obj, "/peripheral-anon");
> -
>       ms->dump_guest_core = true;
>       ms->mem_merge = (QEMU_MADV_MERGEABLE != QEMU_MADV_INVALID);
>       ms->enable_graphics = true;
> diff --git a/qom/object.c b/qom/object.c
> index 214d6eb4c1..2fb0b8418e 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -1734,12 +1734,34 @@ const char *object_property_get_type(Object *obj, const 
> char *name, Error **errp
>       return prop->type;
>   }
>   
> +static const char *const root_containers[] = {
> +    "chardevs",
> +    "objects",
> +    "backend"
> +};
> +
> +static Object *object_root_initialize(void)
> +{

(root_containers[] can be declared here)

> +    Object *root = object_new(TYPE_CONTAINER);
> +    int i;
> +
> +    /*
> +     * Create all QEMU system containers.  "machine" and its sub-containers
> +     * are only created when machine initializes (qemu_create_machine()).

I'm not sure this comment is helpful. Regardless,

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> +     */
> +    for (i = 0; i < ARRAY_SIZE(root_containers); i++) {
> +        object_property_add_new_container(root, root_containers[i]);
> +    }
> +
> +    return root;
> +}

> +
>   Object *object_get_root(void)
>   {
>       static Object *root;
>   
>       if (!root) {
> -        root = object_new(TYPE_CONTAINER);
> +        root = object_root_initialize();
>       }
>   
>       return root;
> diff --git a/system/vl.c b/system/vl.c
> index 3bb8f2db9a..15e35162c6 100644
> --- a/system/vl.c
> +++ b/system/vl.c
> @@ -2112,6 +2112,21 @@ static void parse_memory_options(void)
>       loc_pop(&loc);
>   }
>   
> +static const char *const machine_containers[] = {
> +    "unattached",
> +    "peripheral",
> +    "peripheral-anon"
> +};
> +
> +static void qemu_create_machine_containers(Object *machine)
> +{

(ditto machine_containers[])

> +    int i;
> +
> +    for (i = 0; i < ARRAY_SIZE(machine_containers); i++) {
> +        object_property_add_new_container(machine, machine_containers[i]);
> +    }
> +}
> +
>   static void qemu_create_machine(QDict *qdict)
>   {
>       MachineClass *machine_class = select_machine(qdict, &error_fatal);
> @@ -2120,6 +2135,7 @@ static void qemu_create_machine(QDict *qdict)
>       current_machine = 
> MACHINE(object_new_with_class(OBJECT_CLASS(machine_class)));
>       object_property_add_child(object_get_root(), "machine",
>                                 OBJECT(current_machine));
> +    qemu_create_machine_containers(OBJECT(current_machine));
>       object_property_add_child(container_get(OBJECT(current_machine),
>                                               "/unattached"),
>                                 "sysbus", OBJECT(sysbus_get_default()));