On 5/8/2026 5:54 PM, Pierrick Bouvier wrote:
> We are getting close to be able to link several targets in a single QEMU system
> binary, and the last obstacle on the road is to embed several TargetInfo in the
> same binary. The end result of this series is to have a single definition for
> target_info symbol.
>
> This series adds TargetInfo types in QOM, and retrieve them dynamically(). At
> the moment, we don't deal yet with multiple TargetInfo selection, but install
> all that is needed to be able to do it easily.
>
> Because TargetInfo data is set through class_init, it creates an issue at
> startup, where we may try to instantiate additional (unrelated) types just to
> retrieve the list of "target-info-X" types. Those other types class_init may be
> using target information, to add target specific properties for instance.
> This issue has been fixed by adding a new object_class_get_list_by_name_prefix
> that does not force instantiation of all QOM types, but only those matching a
> specific pattern. This way, we first initialize and retrieve target-info types
> before others.
>
> An alternative would be to leave all this out of QOM, and use startup
> initializer to add them in a single list. However, because all the single-binary
> work has been using QOM where possible, it would be really sad to not use it for
> this final step. Comments are welcome!
>
> Finally, sticking to our promise not create a special "single-binary
> configuration", the goal is to use the *exact* same codepath for normal binaries
> also. It means that even for existing system binaries, the goal will be to use
> QOM to retrieve current target, even if there is only one.
>
> v5
> --
>
> - Fix header guard name for target-info-init.h
> (TARGET_INFO_INIT_H -> QEMU_TARGET_INFO_INIT_H)
> - add a new patch to initialize type_table with TYPE_OBJECT and TYPE_INTERFACE,
> as suggested by Richard
> - use a single class_init for all target-info-* classes.
>
> v4
> --
>
> - Revert to v2 MODULE_INIT_TARGET_INFO as Daniel didn't comment on issues about
> about MODULE_INIT_QOM_EARLY.
>
> v3
> --
>
> - fix rebase mistake for one header guard
> - remove MODULE_INIT_TARGET_INFO and introduce MODULE_INIT_QOM_EARLY, as
> requested by Daniel
>
> v2
> --
>
> - fix header guards
> - introduce new module init step (MODULE_INIT_TARGET_INFO)
> - as a consequence of item above, we need to register TYPE_OBJECT before startup
> - fix xtensa core type registration using type_init instead of static ctor
>
> Pierrick Bouvier (6):
> qom/object: register OBJECT and INTERFACE QOM types before main
> qom/object: initialize type_table in static ctor with fundamental QOM
> types
> target-info: extract target_info() definition in target-info-init.h
> target-info-qom: detect target from QOM
> target-info: replace target_info() in system-mode
> target-info-qom: use a single class_init for target-info-* classes
>
> configs/targets/aarch64-softmmu.c | 6 +--
> configs/targets/arm-softmmu.c | 6 +--
> include/qemu/module.h | 1 +
> include/qemu/target-info-init.h | 63 +++++++++++++++++++++++++++++++
> include/qemu/target-info-qom.h | 31 +++++++++++++++
> qom/object.c | 22 +++--------
> system/vl.c | 4 ++
> target-info-qom.c | 41 ++++++++++++++++++++
> target-info-stub.c | 6 +--
> 9 files changed, 152 insertions(+), 28 deletions(-)
> create mode 100644 include/qemu/target-info-init.h
> create mode 100644 include/qemu/target-info-qom.h
>
v6 sent:
https://lore.kernel.org/qemu-devel/20260512150208.1167711-6-pierrick.bouvier@oss.qualcomm.com/T/#
Regards,
Pierrick