Re: [PATCH 09/12] target-info: register le and be TargetInfo variants

On 8/23/2026 8:07 AM, Yonggang Luo wrote:
> - Register target-info-<name>-le and -be from one system
>   target-info-def.c unit, sharing arch fields.
> - Mark is_default from TARGET_BIG_ENDIAN so riscv/arm stay LE and
>   ppc/s390x stay BE when -target is omitted.
> - Pick the unique default in target_info_qom_set_target() when more
>   than one TargetInfo is registered. Leave user-mode as a single
>   target_info().
> 
> Signed-off-by: Yonggang Luo <[email protected]>
> ---
>  include/qemu/target-info-impl.h |  6 ++++
>  include/qemu/target-info-init.h | 29 +++++++++++++---
>  target-info-def.c               | 61 +++++++++++++++++++++++++--------
>  target-info-qom.c               | 33 ++++++++++++++----
>  4 files changed, 104 insertions(+), 25 deletions(-)
> 
> diff --git a/include/qemu/target-info-impl.h b/include/qemu/target-info-impl.h
> index de329ec2b86..b4222e4455e 100644
> --- a/include/qemu/target-info-impl.h
> +++ b/include/qemu/target-info-impl.h
> @@ -23,6 +23,12 @@ typedef struct TargetInfo {
>      const char *cpu_type;
>      /* related to TARGET_BIG_ENDIAN definition */
>      EndianMode endianness;
> +    /*
> +     * True on the endian variant that matches this translation unit's
> +     * TARGET_BIG_ENDIAN. target_info_qom_set_target() uses this when
> +     * more than one TargetInfo is registered and -target is omitted.
> +     */
> +    bool is_default;
>      /*
>       * runtime equivalent of
>       *   TARGET_PAGE_BITS_VARY ? TARGET_PAGE_BITS_LEGACY : TARGET_PAGE_BITS
> diff --git a/include/qemu/target-info-init.h b/include/qemu/target-info-init.h
> index b7024c9faef..25d00adcc66 100644
> --- a/include/qemu/target-info-init.h
> +++ b/include/qemu/target-info-init.h
> @@ -37,15 +37,34 @@ const TargetInfo *target_info(void)     \
>  #include "qemu/target-info-qom.h"
>  #include "qom/object.h"
>  
> -#define target_info_init(ti_var)                                            \
> -static const TypeInfo target_info_qom_target_type_info = {                  \
> -    .name =  TYPE_TARGET_INFO"-"TARGET_NAME,                                \
> +/*
> + * QOM type names are target-info-<TARGET_NAME>-le and -be so both
> + * endian variants can be registered from one system translation unit.
> + */
> +#define TARGET_INFO_QOM_SUFFIX_0 "-le"
> +#define TARGET_INFO_QOM_SUFFIX_1 "-be"
> +
> +#define TARGET_INFO_QOM_NAME(sel)                                           \
> +    TYPE_TARGET_INFO "-" TARGET_NAME glue(TARGET_INFO_QOM_SUFFIX_, sel)
> +
> +#define TARGET_INFO_QOM_TYPEINFO(ti_var, sel)                               \
> +static const TypeInfo glue(target_info_qom_type_, sel) = {                  \
> +    .name = TARGET_INFO_QOM_NAME(sel),                                      \
>      .parent = TYPE_TARGET_INFO,                                             \
>      .instance_size = sizeof(TargetInfoQom),                                 \
>      .class_size = sizeof(TargetInfoQomClass),                               \
>      .class_data = &ti_var,                                                  \
> -};                                                                          \
> -DEFINE_TARGET_INFO_TYPE(target_info_qom_target_type_info)
> +}
> +
> +#define target_info_init_le_be(ti_le, ti_be)                                \
> +TARGET_INFO_QOM_TYPEINFO(ti_le, 0);                                         \
> +TARGET_INFO_QOM_TYPEINFO(ti_be, 1);                                         \
> +static void do_qemu_init_target_info(void)                                  \
> +{                                                                           \
> +    type_register_static(&target_info_qom_type_0);                          \
> +    type_register_static(&target_info_qom_type_1);                          \
> +}                                                                           \
> +module_init(do_qemu_init_target_info, MODULE_INIT_TARGET_INFO)
>  
>  #endif /* CONFIG_USER_ONLY */
>  #endif /* COMPILING_PER_TARGET */
> diff --git a/target-info-def.c b/target-info-def.c
> index 5d38e405735..6722c43a08f 100644
> --- a/target-info-def.c
> +++ b/target-info-def.c
> @@ -28,39 +28,72 @@ QEMU_BUILD_BUG_ON(offsetof(ArchCPU, env) != sizeof(CPUState));
>  QEMU_BUILD_BUG_ON(TARGET_PAGE_BITS < TARGET_PAGE_BITS_MIN);
>  #endif
>  
> -static const TargetInfo target_info_def = {
> -    .target_name = TARGET_NAME,
> -    .target_arch = glue(SYS_EMU_TARGET_, TARGET_ARCH),
> -    .long_bits = TARGET_LONG_BITS,
> -    .cpu_type = CPU_RESOLVING_TYPE,
> -    .endianness = TARGET_BIG_ENDIAN ? ENDIAN_MODE_BIG : ENDIAN_MODE_LITTLE,
>  #ifdef TARGET_PAGE_BITS_VARY
> -    .page_bits_vary = true,
>  # ifdef TARGET_PAGE_BITS_LEGACY
> +#  define TARGET_INFO_PAGE_BITS \
> +    .page_bits_vary = true, \
>      .page_bits_init = TARGET_PAGE_BITS_LEGACY,
> +# else
> +#  define TARGET_INFO_PAGE_BITS \
> +    .page_bits_vary = true,
>  # endif
>  #else
> -    .page_bits_vary = false,
> +# define TARGET_INFO_PAGE_BITS \
> +    .page_bits_vary = false, \
>      .page_bits_init = TARGET_PAGE_BITS,
>  #endif
>  
>  #ifndef CONFIG_USER_ONLY
>  # ifdef CONFIG_MULTIPROCESS
> -    .config_multiprocess = true,
> +#  define TARGET_INFO_CONFIG_MULTIPROCESS .config_multiprocess = true,
>  # else
> -    .config_multiprocess = false,
> +#  define TARGET_INFO_CONFIG_MULTIPROCESS .config_multiprocess = false,
>  # endif
>  # ifdef CONFIG_NITRO
> -    .config_nitro = true,
> +#  define TARGET_INFO_CONFIG_NITRO .config_nitro = true,
>  # else
> -    .config_nitro = false,
> +#  define TARGET_INFO_CONFIG_NITRO .config_nitro = false,
>  # endif
>  # ifdef CONFIG_XEN
> -    .config_xen = true,
> +#  define TARGET_INFO_CONFIG_XEN .config_xen = true,
>  # else
> -    .config_xen = false,
> +#  define TARGET_INFO_CONFIG_XEN .config_xen = false,
>  # endif
> +# define TARGET_INFO_CONFIG \
> +    TARGET_INFO_CONFIG_MULTIPROCESS \
> +    TARGET_INFO_CONFIG_NITRO \
> +    TARGET_INFO_CONFIG_XEN
> +#else
> +# define TARGET_INFO_CONFIG
>  #endif
> +
> +#define TARGET_INFO_COMMON                                                  \
> +    .target_name = TARGET_NAME,                                             \
> +    .target_arch = glue(SYS_EMU_TARGET_, TARGET_ARCH),                      \
> +    .long_bits = TARGET_LONG_BITS,                                          \
> +    .cpu_type = CPU_RESOLVING_TYPE,                                         \
> +    TARGET_INFO_PAGE_BITS                                                   \
> +    TARGET_INFO_CONFIG
> +
> +#ifdef CONFIG_USER_ONLY
> +static const TargetInfo target_info_def = {
> +    TARGET_INFO_COMMON
> +    .endianness = TARGET_BIG_ENDIAN ? ENDIAN_MODE_BIG : ENDIAN_MODE_LITTLE,
>  };
>  
>  target_info_init(target_info_def)
> +#else
> +static const TargetInfo target_info_le = {
> +    TARGET_INFO_COMMON
> +    .endianness = ENDIAN_MODE_LITTLE,
> +    .is_default = !TARGET_BIG_ENDIAN,
> +};
> +
> +static const TargetInfo target_info_be = {
> +    TARGET_INFO_COMMON
> +    .endianness = ENDIAN_MODE_BIG,
> +    .is_default = TARGET_BIG_ENDIAN,
> +};
> +
> +target_info_init_le_be(target_info_le, target_info_be)
> +#endif
> diff --git a/target-info-qom.c b/target-info-qom.c
> index 68ad734049c..2c1c57b05fd 100644
> --- a/target-info-qom.c
> +++ b/target-info-qom.c
> @@ -90,13 +90,34 @@ const TargetInfo *target_info(void)
>  void target_info_qom_set_target(void)
>  {
>      g_autoptr(GSList) targets = object_class_get_list(TYPE_TARGET_INFO, false);
> -
> +    const TargetInfo *chosen = NULL;
>      size_t num_found = g_slist_length(targets);
> -    if (num_found != 1) {
> -        error_setg(&error_fatal, num_found == 0 ?
> -                                 "no target-info is available" :
> -                                 "more than one target-info is available");
> +    size_t num_default = 0;
> +
> +    if (num_found == 0) {
> +        error_setg(&error_fatal, "no target-info is available");
> +    }
> +
> +    if (num_found == 1) {
> +        target_info_ptr = TARGET_INFO_CLASS(targets->data)->target_info;
> +        return;
> +    }
> +
> +    for (GSList *l = targets; l; l = l->next) {
> +        const TargetInfo *ti = TARGET_INFO_CLASS(l->data)->target_info;
> +
> +        if (ti->is_default) {
> +            num_default++;
> +            chosen = ti;
> +        }
> +    }
> +
> +    if (num_default != 1) {
> +        error_setg(&error_fatal, num_default == 0 ?
> +                                 "no default target-info is available" :
> +                                 "more than one default target-info "
> +                                 "is available");
>      }
>  
> -    target_info_ptr = TARGET_INFO_CLASS(targets->data)->target_info;
> +    target_info_ptr = chosen;
>  }

Is it representing existing targets, or adding new ones per endianness?
I'm not sure if the goal is to add new binaries, or mimic existing ones
with specific parameters.