[Qemu-devel] [PATCH 04/10] s390x/kvm: Log unmanageable external interruptions

[Cornelia Huck <cornelia.huck@de.ibm.com>]

From: Thomas Huth <thuth@linux.vnet.ibm.com>

Interception code 0x14 only drops to userspace when an unmanageable
external interruption interception occured (e.g. if the External New
PSW does not disable external interruptions). Instead of bailing out
via the default handler, it is better to inform the user with a
proper error message that also includes the bad PSW, and to stop
the affected CPU with a panic event instead.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
 target-s390x/kvm.c |   35 +++++++++++++++++++++++++++++------
 1 file changed, 29 insertions(+), 6 deletions(-)

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 0a2a205..be703bd 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -83,6 +83,7 @@
 #define DIAG_KVM_BREAKPOINT             0x501
 
 #define ICPT_INSTRUCTION                0x04
+#define ICPT_EXT_INT                    0x14
 #define ICPT_WAITPSW                    0x1c
 #define ICPT_SOFT_INTERCEPT             0x24
 #define ICPT_CPU_STOP                   0x28
@@ -930,6 +931,28 @@ static bool is_special_wait_psw(CPUState *cs)
     return cs->kvm_run->psw_addr == 0xfffUL;
 }
 
+static void guest_panicked(void)
+{
+    QObject *data;
+
+    data = qobject_from_jsonf("{ 'action': %s }", "pause");
+    monitor_protocol_event(QEVENT_GUEST_PANICKED, data);
+    qobject_decref(data);
+
+    vm_stop(RUN_STATE_GUEST_PANICKED);
+}
+
+static void unmanageable_intercept(S390CPU *cpu, const char *str, int pswoffset)
+{
+    CPUState *cs = CPU(cpu);
+
+    error_report("Unmanageable %s! CPU%i new PSW: 0x%016lx:%016lx",
+                 str, cs->cpu_index, ldq_phys(cs->as, cpu->env.psa + pswoffset),
+                 ldq_phys(cs->as, cpu->env.psa + pswoffset + 8));
+    s390_del_running_cpu(cpu);
+    guest_panicked();
+}
+
 static int handle_intercept(S390CPU *cpu)
 {
     CPUState *cs = CPU(cpu);
@@ -943,18 +966,18 @@ static int handle_intercept(S390CPU *cpu)
         case ICPT_INSTRUCTION:
             r = handle_instruction(cpu, run);
             break;
+        case ICPT_EXT_INT:
+            unmanageable_intercept(cpu, "external interrupt",
+                                   offsetof(LowCore, external_new_psw));
+            r = EXCP_HALTED;
+            break;
         case ICPT_WAITPSW:
             /* disabled wait, since enabled wait is handled in kernel */
             if (s390_del_running_cpu(cpu) == 0) {
                 if (is_special_wait_psw(cs)) {
                     qemu_system_shutdown_request();
                 } else {
-                    QObject *data;
-
-                    data = qobject_from_jsonf("{ 'action': %s }", "pause");
-                    monitor_protocol_event(QEVENT_GUEST_PANICKED, data);
-                    qobject_decref(data);
-                    vm_stop(RUN_STATE_GUEST_PANICKED);
+                    guest_panicked();
                 }
             }
             r = EXCP_HALTED;
-- 
1.7.9.5