target/s390x: Rely on unwinding in s390_cpu_virt_mem_rw

For TCG, we will always call s390_cpu_virt_mem_handle_exc,
which will go through the unwinder to set ILEN.  For KVM,
we do not go through do_program_interrupt, so this argument
is unused.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20191001171614.8405-15-richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>

target/s390x/mmu_helper.c

@@ -510,7 +510,7 @@ int s390_cpu_virt_mem_rw(S390CPU *cpu, vaddr laddr, uint8_t ar, void *hostbuf,
 
     ret = translate_pages(cpu, laddr, nr_pages, pages, is_write, &tec);
     if (ret) {
-        trigger_access_exception(&cpu->env, ret, ILEN_AUTO, tec);
+        trigger_access_exception(&cpu->env, ret, ILEN_UNWIND, tec);
     } else if (hostbuf != NULL) {
         /* Copy data by stepping through the area page by page */
         for (i = 0; i < nr_pages; i++) {