s390x/kvm: don't enable key wrapping if msa3 is disabled

As the CPU model now controls msa3, trying to set wrapping keys without
msa3 being around/enable in the kernel will produce misleading errors.

So let's simply not configure key wrapping if msa3 is not enabled and
make compat machines with disabled CPU model work correctly.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Message-Id: <20160905085244.99980-25-dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

target-s390x/cpu_models.c

@@ -155,6 +155,9 @@ bool s390_has_feat(S390Feat feat)
             if (feat == S390_FEAT_RUNTIME_INSTRUMENTATION) {
                 return kvm_s390_get_ri();
             }
+            if (feat == S390_FEAT_MSA_EXT_3) {
+                return true;
+            }
         }
 #endif
         return 0;

target-s390x/kvm.c

@@ -260,8 +260,10 @@ static void kvm_s390_init_dea_kw(void)
 
 void kvm_s390_crypto_reset(void)
 {
-    kvm_s390_init_aes_kw();
-    kvm_s390_init_dea_kw();
+    if (s390_has_feat(S390_FEAT_MSA_EXT_3)) {
+        kvm_s390_init_aes_kw();
+        kvm_s390_init_dea_kw();
+    }
 }
 
 int kvm_arch_init(MachineState *ms, KVMState *s)