@@ -337,8 +337,15 @@ unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu)
break;
case CPU_STATE_OPERATING:
case CPU_STATE_LOAD:
- /* unhalt the cpu for common infrastructure */
- s390_cpu_unhalt(cpu);
+ /*
+ * Starting a CPU with a PSW WAIT bit set:
+ * KVM: handles this internally and triggers another WAIT exit.
+ * TCG: will actually try to continue to run. Don't unhalt, will
+ * be done when the CPU actually has work (an interrupt).
+ */
+ if (!tcg_enabled() || !(cpu->env.psw.mask & PSW_MASK_WAIT)) {
+ s390_cpu_unhalt(cpu);
+ }
break;
default:
error_report("Requested CPU state is not a valid S390 CPU state: %u",
@@ -232,8 +232,12 @@ static void sigp_restart(CPUState *cs, run_on_cpu_data arg)
case CPU_STATE_STOPPED:
/* the restart irq has to be delivered prior to any other pending irq */
cpu_synchronize_state(cs);
- do_restart_interrupt(&cpu->env);
+ /*
+ * Set OPERATING (and unhalting) before loading the restart PSW.
+ * load_psw() will then properly halt the CPU again if necessary (TCG).
+ */
s390_cpu_set_state(CPU_STATE_OPERATING, cpu);
+ do_restart_interrupt(&cpu->env);
break;
case CPU_STATE_OPERATING:
cpu_inject_restart(cpu);