s390x/kvm: deliver SIGP RESTART directly if stopped

According to the PoP, a restart irq has to be delivered "without first honoring
any other pending interruptions", if a cpu is in the STOPPED state.

While it is hard to implement this case in kvm, it can easily be handled in qemu.

Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Message-Id: <1424783731-43426-10-git-send-email-jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 702351331f70154118fb8520a849c45fc355eea5..ec64b7e5064578faf2bc6531ae10971f9206a038 100644 (file)
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -1254,8 +1254,17 @@ static void sigp_restart(void *arg)
         .type = KVM_S390_RESTART,
     };
 
-    kvm_s390_vcpu_interrupt(si->cpu, &irq);
-    s390_cpu_set_state(CPU_STATE_OPERATING, si->cpu);
+    switch (s390_cpu_get_state(si->cpu)) {
+    case CPU_STATE_STOPPED:
+        /* the restart irq has to be delivered prior to any other pending irq */
+        cpu_synchronize_state(CPU(si->cpu));
+        do_restart_interrupt(&si->cpu->env);
+        s390_cpu_set_state(CPU_STATE_OPERATING, si->cpu);
+        break;
+    case CPU_STATE_OPERATING:
+        kvm_s390_vcpu_interrupt(si->cpu, &irq);
+        break;
+    }
     si->cc = SIGP_CC_ORDER_CODE_ACCEPTED;
 }