Pierrick has proposed a series that introduces a concept of runtime conditionals to the QAPI schema, in order to adapt the TARGET_* conditionals currently used at build time:
https://lists.nongnu.org/archive/html/qemu-devel/2025-05/msg01699.html For the sake of comparison & evaluation, this series illustrates the alternative approach that we've discussed of entirely removing any concept of TARGET_* conditionals. With this the QAPI schema varies solely based on CONFIG_* conditionals, and is thus invariant across different target emulators. In this PoC I've taken the minimal effort approach to the problem. The QAPI schema has removed the TARGET_* conditionals and in order to make all the emulators then compile, the stubs/ directory is populated with a bunch of files to provide dummy impls of the target specific QMP commands. This is sufficient to make the current QEMU binaries build successfully. To make the "single binary" concept work, however, would require additional followup work to eliminate the stubs. Instead of having stubs we would need to de-couple the QMP command impl from the machine internals. This would likely require greater use of interfaces and/or virtual method dispatchers on the machine class. This would enable the 'qmp_XXXXX' command impls to exist once. Then they call out to virtual methods on the machine to provide the real impl, and/or generate an error if the virtual method is not implemented for the machine. Daniel P. Berrangé (9): qapi: expose rtc-reset-reinjection command unconditionally qapi: expand docs for SEV commands qapi: make SEV commands unconditionally available qapi: expose query-gic-capability command unconditionally qapi: make SGX commands unconditionally available qapi: make Xen event commands unconditionally available qapi: remove the misc-target.json file qapi: make most CPU commands unconditionally available qapi: make s390x specific CPU commands unconditionally available Philippe Mathieu-Daudé (1): qapi: Make CpuModelExpansionInfo::deprecated-props optional and generic hw/i386/kvm/xen-stubs.c | 13 - hw/i386/kvm/xen_evtchn.c | 2 +- hw/i386/monitor.c | 2 +- hw/i386/sgx-stub.c | 13 - hw/i386/sgx.c | 2 +- hw/s390x/cpu-topology.c | 4 +- hw/s390x/s390-skeys.c | 1 - include/hw/s390x/cpu-topology.h | 2 +- qapi/machine-s390x.json | 120 ++++++ qapi/machine-target.json | 523 -------------------------- qapi/machine.json | 363 ++++++++++++++++++ qapi/meson.build | 5 +- qapi/misc-arm.json | 49 +++ qapi/misc-i386.json | 479 +++++++++++++++++++++++ qapi/misc-target.json | 504 ------------------------- qapi/qapi-schema.json | 5 +- stubs/meson.build | 8 + stubs/monitor-arm-gic.c | 12 + stubs/monitor-cpu-s390x-kvm.c | 22 ++ stubs/monitor-cpu-s390x.c | 23 ++ stubs/monitor-cpu.c | 21 ++ stubs/monitor-i386-rtc.c | 10 + stubs/monitor-i386-sev.c | 36 ++ stubs/monitor-i386-sgx.c | 17 + stubs/monitor-i386-xen.c | 16 + target/arm/arm-qmp-cmds.c | 4 +- target/i386/cpu-system.c | 2 +- target/i386/cpu.c | 2 +- target/i386/monitor.c | 1 - target/i386/sev-system-stub.c | 32 -- target/i386/sev.c | 2 +- target/loongarch/loongarch-qmp-cmds.c | 2 +- target/mips/system/mips-qmp-cmds.c | 12 +- target/ppc/ppc-qmp-cmds.c | 12 +- target/riscv/riscv-qmp-cmds.c | 2 +- target/s390x/cpu_models_system.c | 2 +- tests/qtest/qmp-cmd-test.c | 1 + 37 files changed, 1219 insertions(+), 1107 deletions(-) create mode 100644 qapi/machine-s390x.json delete mode 100644 qapi/machine-target.json create mode 100644 qapi/misc-arm.json create mode 100644 qapi/misc-i386.json create mode 100644 stubs/monitor-arm-gic.c create mode 100644 stubs/monitor-cpu-s390x-kvm.c create mode 100644 stubs/monitor-cpu-s390x.c create mode 100644 stubs/monitor-cpu.c create mode 100644 stubs/monitor-i386-rtc.c create mode 100644 stubs/monitor-i386-sev.c create mode 100644 stubs/monitor-i386-sgx.c create mode 100644 stubs/monitor-i386-xen.c -- 2.49.0
