s390/sclp: improve special wait psw logic

There is a special quiesce PSW that we check for "shutdown". Otherwise disabled
wait is detected as "crashed". Architecturally we must only check PSW bits
116-127. Fix this.

Cc: qemu-stable@nongnu.org
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <1582204582-22995-1-git-send-email-borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
(cherry picked from commit 8b51c09)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

target/s390x/helper.c

@@ -89,7 +89,7 @@ hwaddr s390_cpu_get_phys_addr_debug(CPUState *cs, vaddr vaddr)
 static inline bool is_special_wait_psw(uint64_t psw_addr)
 {
     /* signal quiesce */
-    return psw_addr == 0xfffUL;
+    return (psw_addr & 0xfffUL) == 0xfffUL;
 }
 
 void s390_handle_wait(S390CPU *cpu)