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

On Tue, Aug 25, 2026 at 12:22 AM Pierrick Bouvier <
[email protected]> wrote:
>
> 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.


Is optional now, not a force requirement, this is needed when we use GDB
debug qemu riscv-be, as gdbstub are depends on target_info


--
         此致
礼
罗勇刚
Yours
    sincerely,
Yonggang Luo