[RFC PATCH v5 1/1] s390x: sigp: Reorder the SIGP STOP code

[Eric Farman <farman@linux.ibm.com>]

Let's wait to mark the VCPU STOPPED until the possible
STORE STATUS operation is completed, so that we know the
CPU is fully stopped and done doing anything. (When we
also clear the possible sigp_order field for STOP orders.)

Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
 target/s390x/sigp.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/target/s390x/sigp.c b/target/s390x/sigp.c
index 51c727834c..9dd977349a 100644
--- a/target/s390x/sigp.c
+++ b/target/s390x/sigp.c
@@ -139,7 +139,7 @@ static void sigp_stop_and_store_status(CPUState *cs, run_on_cpu_data arg)
     case S390_CPU_STATE_OPERATING:
         cpu->env.sigp_order = SIGP_STOP_STORE_STATUS;
         cpu_inject_stop(cpu);
-        /* store will be performed in do_stop_interrup() */
+        /* store will be performed in do_stop_interrupt() */
         break;
     case S390_CPU_STATE_STOPPED:
         /* already stopped, just store the status */
@@ -479,13 +479,17 @@ void do_stop_interrupt(CPUS390XState *env)
 {
     S390CPU *cpu = env_archcpu(env);
 
-    if (s390_cpu_set_state(S390_CPU_STATE_STOPPED, cpu) == 0) {
-        qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
-    }
+    /*
+     * Complete the STOP operation before exposing the CPU as
+     * STOPPED to the system.
+     */
     if (cpu->env.sigp_order == SIGP_STOP_STORE_STATUS) {
         s390_store_status(cpu, S390_STORE_STATUS_DEF_ADDR, true);
     }
     env->sigp_order = 0;
+    if (s390_cpu_set_state(S390_CPU_STATE_STOPPED, cpu) == 0) {
+        qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
+    }
     env->pending_int &= ~INTERRUPT_STOP;
 }
 
-- 
2.32.0