diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c index 40d6980229..271c5ce652 100644 --- a/target/s390x/cpu.c +++ b/target/s390x/cpu.c @@ -218,11 +218,18 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp) #endif s390_cpu_gdb_init(cs); qemu_init_vcpu(cs); -#if !defined(CONFIG_USER_ONLY) - run_on_cpu(cs, s390_do_cpu_full_reset, RUN_ON_CPU_NULL); -#else - cpu_reset(cs); -#endif + + /* + * KVM requires the initial CPU reset ioctl to be executed on the target + * CPU thread. CPU hotplug under single-threaded TCG will not work with + * run_on_cpu(), as run_on_cpu() will not work properly if called while + * the main thread is already running but the CPU hasn't been realized. + */ + if (kvm_enabled()) { + run_on_cpu(cs, s390_do_cpu_full_reset, RUN_ON_CPU_NULL); + } else { + cpu_reset(cs); + } scc->parent_realize(dev, &err); out: