GCC 10.1 introduced the -moutline-atomics option on Aarch64. This options is enabled by default, and triggers a link failure:
Undefined symbols for architecture arm64: "___aarch64_cas1_acq_rel", referenced from: _qmp_migrate_recover in migration_migration.c.o _cpu_atomic_cmpxchgb_mmu in accel_tcg_cputlb.c.o _cpu_atomic_fetch_sminb_mmu in accel_tcg_cputlb.c.o _cpu_atomic_fetch_uminb_mmu in accel_tcg_cputlb.c.o _cpu_atomic_fetch_smaxb_mmu in accel_tcg_cputlb.c.o _cpu_atomic_fetch_umaxb_mmu in accel_tcg_cputlb.c.o _cpu_atomic_smin_fetchb_mmu in accel_tcg_cputlb.c.o ... "___aarch64_ldadd4_acq_rel", referenced from: _multifd_recv_new_channel in migration_multifd.c.o _monitor_event in monitor_hmp.c.o _handle_hmp_command in monitor_hmp.c.o _colo_compare_finalize in net_colo-compare.c.o _flatview_unref in softmmu_memory.c.o _virtio_scsi_hotunplug in hw_scsi_virtio-scsi.c.o _tcg_register_thread in tcg_tcg.c.o ... "___aarch64_swp4_acq", referenced from: _qemu_spin_lock in softmmu_cpu-timers.c.o _cpu_get_ticks in softmmu_cpu-timers.c.o _qemu_spin_lock in softmmu_icount.c.o _cpu_exec in accel_tcg_cpu-exec.c.o _page_flush_tb_1.isra.0 in accel_tcg_translate-all.c.o _page_entry_lock in accel_tcg_translate-all.c.o _do_tb_phys_invalidate in accel_tcg_translate-all.c.o ... QEMU implements its own atomic operations using C11 builtin helpers. Disable the GCC out-of-line atomic ops. Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org> --- Cc: Stefan Hajnoczi <stefa...@redhat.com> Cc: Paolo Bonzini <pbonz...@redhat.com> Clearly out of my understanding, but at least it links and the qtests pass. --- configure | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/configure b/configure index 06c03cebd3..3217aa22cb 100755 --- a/configure +++ b/configure @@ -2826,6 +2826,18 @@ else avx512f_opt="no" fi +######################################### +# Disable out-of-line atomic operations. + +case "$cpu" in + aarch64) + write_c_skeleton; + if compile_prog "$CPU_CFLAGS -Werror -mno-outline-atomics" "" ; then + CPU_CFLAGS="-mno-outline-atomics $CPU_CFLAGS" + fi + ;; +esac + ######################################## # check if __[u]int128_t is usable. -- 2.34.1