target-s390x: PER instruction-fetch nullification event support

For the instruction-fetch nullification event, we just reuse the
existing instruction-fetch code and trigger the exception immediately
in that case.

There is no need to save the CPU state in the TCG code as it has been
saved by the previous instruction before calling the per_check_exception
helper.
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NAlexander Graf <agraf@suse.de>

target-s390x/misc_helper.c

@@ -625,6 +625,18 @@ void HELPER(per_ifetch)(CPUS390XState *env, uint64_t addr)
     if ((env->cregs[9] & PER_CR9_EVENT_IFETCH) && get_per_in_range(env, addr)) {
         env->per_address = addr;
         env->per_perc_atmid = PER_CODE_EVENT_IFETCH | get_per_atmid(env);
+
+        /* If the instruction has to be nullified, trigger the
+           exception immediately. */
+        if (env->cregs[9] & PER_CR9_EVENT_NULLIFICATION) {
+            CPUState *cs = CPU(s390_env_get_cpu(env));
+
+            env->int_pgm_code = PGM_PER;
+            env->int_pgm_ilen = get_ilen(cpu_ldub_code(env, addr));
+
+            cs->exception_index = EXCP_PGM;
+            cpu_loop_exit(cs);
+        }
     }
 }
 #endif