On 4/18/25 10:28, Philippe Mathieu-Daudé wrote:
> Binaries can register a QOM type to filter their machines
> by filling their TargetInfo::machine_typename field.
>
> This can be used by example by main() -> machine_help_func()
> to filter the machines list.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> meson.build | 1 +
> include/qemu/target_info-impl.h | 3 +++
> include/qemu/target_info.h | 8 ++++++++
> system/vl.c | 3 ++-
> target_info-qom.c | 15 +++++++++++++++
> target_info-stub.c | 2 ++
> target_info.c | 5 +++++
> 7 files changed, 36 insertions(+), 1 deletion(-)
> create mode 100644 target_info-qom.c
>
> diff --git a/meson.build b/meson.build
> index 49a050a28a3..168b07b5887 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -3808,6 +3808,7 @@ common_ss.add(pagevary)
> specific_ss.add(files('page-target.c', 'page-vary-target.c'))
>
> common_ss.add(files('target_info.c'))
> +system_ss.add(files('target_info-qom.c'))
> specific_ss.add(files('target_info-stub.c'))
>
> subdir('backends')
> diff --git a/include/qemu/target_info-impl.h b/include/qemu/target_info-impl.h
> index 11b92796b28..e3344278a92 100644
> --- a/include/qemu/target_info-impl.h
> +++ b/include/qemu/target_info-impl.h
> @@ -16,6 +16,9 @@ typedef struct TargetInfo {
> /* runtime equivalent of TARGET_NAME definition */
> const char *const target_name;
>
> + /* QOM typename machines for this binary must implement */
> + const char *const machine_typename;
> +
> } TargetInfo;
>
> const TargetInfo *target_info(void);
> diff --git a/include/qemu/target_info.h b/include/qemu/target_info.h
> index 3f6cbbbd300..c67b97d66f3 100644
> --- a/include/qemu/target_info.h
> +++ b/include/qemu/target_info.h
> @@ -16,4 +16,12 @@
> */
> const char *target_name(void);
>
> +/**
> + * target_machine_typename:
> + *
> + * Returns: Name of the QOM interface implemented by machines
> + * usable on this target binary.
> + */
> +const char *target_machine_typename(void);
> +
> #endif
> diff --git a/system/vl.c b/system/vl.c
> index d8a0fe713c9..8fb18f82e20 100644
> --- a/system/vl.c
> +++ b/system/vl.c
> @@ -27,6 +27,7 @@
> #include "qemu/datadir.h"
> #include "qemu/units.h"
> #include "qemu/module.h"
> +#include "qemu/target_info.h"
> #include "exec/cpu-common.h"
> #include "exec/page-vary.h"
> #include "hw/qdev-properties.h"
> @@ -1564,7 +1565,7 @@ static void machine_help_func(const QDict *qdict)
> GSList *el;
> const char *type = qdict_get_try_str(qdict, "type");
>
> - machines = object_class_get_list(TYPE_MACHINE, false);
> + machines = object_class_get_list(target_machine_typename(), false);
> if (type) {
> ObjectClass *machine_class = OBJECT_CLASS(find_machine(type, machines));
> if (machine_class) {
> diff --git a/target_info-qom.c b/target_info-qom.c
> new file mode 100644
> index 00000000000..a6fd8f1d5a3
> --- /dev/null
> +++ b/target_info-qom.c
> @@ -0,0 +1,15 @@
> +/*
> + * QEMU binary/target API (QOM types)
> + *
> + * Copyright (c) Linaro
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qom/object.h"
> +
> +static const TypeInfo target_info_types[] = {
> +};
> +
> +DEFINE_TYPES(target_info_types)
> diff --git a/target_info-stub.c b/target_info-stub.c
> index f15972c5b22..14e6d5e68d2 100644
> --- a/target_info-stub.c
> +++ b/target_info-stub.c
> @@ -8,9 +8,11 @@
>
> #include "qemu/osdep.h"
> #include "qemu/target_info-impl.h"
> +#include "hw/boards.h"
>
> static const TargetInfo target_info_stub = {
> .target_name = TARGET_NAME,
> + .machine_typename = TYPE_MACHINE,
> };
Excellent, even more simple than returning NULL.
>
> const TargetInfo *target_info(void)
> diff --git a/target_info.c b/target_info.c
> index 48c4a413326..1de4334ecc5 100644
> --- a/target_info.c
> +++ b/target_info.c
> @@ -14,3 +14,8 @@ const char *target_name(void)
> {
> return target_info()->target_name;
> }
> +
> +const char *target_machine_typename(void)
> +{
> + return target_info()->machine_typename;
> +}
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>