KVM: s390: Bugfix and cleanups

There is one important bug fix for a potential memory corruption
 and/or guest errors for guests with 63 or 64 vCPUs. This fix would
 qualify for 4.3 but is some days too late giving that we are
 about to release 4.3.
 Given that this patch is cc stable >= 3.15 anyway, we can handle
 it via 4.4. merge window.
 
 This pull reuqest also contains two cleanups.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.14 (GNU/Linux)
 
 iQIcBAABAgAGBQJWMjS5AAoJEBF7vIC1phx80FMP/Rbm+DOrPfAQJteIxTvm5TmM
 LjZjdZ6xCuUH+css6mtziQmA3GX2n4wPgrh5oU7ZYewvvNf6KXfzSj8lh0Y40xvE
 LELMrleip1A2E+lix3jcYrUnCtuGUVvbAlEbh3B51GeMuS55NdMbTJjDz+YCZS77
 TVwvzXiTiV81SEE0g5F6ydAIHoa+qTwNtf9LOqP33DNonjqOZVIbxJpU7c1gvm/N
 2GXMqds7SU/iI59cQCKdeoPcUfuq/tyQOaSQShfbwZ34yw10IBd+24roJp77jYo7
 txBrlJEP1P7OjALrzT4PHieZ3rSUgxFPhdUvdgbgNI5YSIcSOWbKKFGXkQ0QJYJ2
 dZh58qY12LFLkC5PJbJzEv9cz/wI+O27DT2dFluhvTNSgI09yeQ7yuMqYhwqBsSS
 NPQdUQ+D/TF1oZh1UVEEIk4UVURB9wRhqrPMeeNTNcawEEqxYGtpBw19AdeacMCk
 diSdPVgN3qQCoR7jR3LR0S28M1i24PyayQWeKwLWitm7wGp663bfjkpnJCOn9jXD
 /LBPYJDQDCdzBd1ynoAj+BK7Uau++LiJUeozKf/ohek3c+N+N/bcFVY9liGnFFub
 DVHIfGEztf3t6TXpqnJ4uxGjafonx/WsfPqGRdOnB6OZ1WVB7MZIAUJBAmLtFHvv
 N0FkHKfrRSRTtsUb6g5e
 =w01Y
 -----END PGP SIGNATURE-----

Merge tag 'kvm-s390-next-20151028' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

KVM: s390: Bugfix and cleanups

There is one important bug fix for a potential memory corruption
and/or guest errors for guests with 63 or 64 vCPUs. This fix would
qualify for 4.3 but is some days too late giving that we are
about to release 4.3.
Given that this patch is cc stable >= 3.15 anyway, we can handle
it via 4.4. merge window.

This pull request also contains two cleanups.

arch/s390/kvm/intercept.c

@@ -336,28 +336,28 @@ static int handle_partial_execution(struct kvm_vcpu *vcpu)
 	return -EOPNOTSUPP;
 }
 
-static const intercept_handler_t intercept_funcs[] = {
-	[0x00 >> 2] = handle_noop,
-	[0x04 >> 2] = handle_instruction,
-	[0x08 >> 2] = handle_prog,
-	[0x10 >> 2] = handle_noop,
-	[0x14 >> 2] = handle_external_interrupt,
-	[0x18 >> 2] = handle_noop,
-	[0x1C >> 2] = kvm_s390_handle_wait,
-	[0x20 >> 2] = handle_validity,
-	[0x28 >> 2] = handle_stop,
-	[0x38 >> 2] = handle_partial_execution,
-};
-
 int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
 {
-	intercept_handler_t func;
-	u8 code = vcpu->arch.sie_block->icptcode;
-
-	if (code & 3 || (code >> 2) >= ARRAY_SIZE(intercept_funcs))
+	switch (vcpu->arch.sie_block->icptcode) {
+	case 0x00:
+	case 0x10:
+	case 0x18:
+		return handle_noop(vcpu);
+	case 0x04:
+		return handle_instruction(vcpu);
+	case 0x08:
+		return handle_prog(vcpu);
+	case 0x14:
+		return handle_external_interrupt(vcpu);
+	case 0x1c:
+		return kvm_s390_handle_wait(vcpu);
+	case 0x20:
+		return handle_validity(vcpu);
+	case 0x28:
+		return handle_stop(vcpu);
+	case 0x38:
+		return handle_partial_execution(vcpu);
+	default:
 		return -EOPNOTSUPP;
-	func = intercept_funcs[code >> 2];
-	if (func)
-		return func(vcpu);
-	return -EOPNOTSUPP;
+	}
 }

arch/s390/kvm/kvm-s390.c

@@ -514,7 +514,7 @@ static int kvm_s390_set_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)
 
 	if (gtod_high != 0)
 		return -EINVAL;
-	VM_EVENT(kvm, 3, "SET: TOD extension: 0x%x\n", gtod_high);
+	VM_EVENT(kvm, 3, "SET: TOD extension: 0x%x", gtod_high);
 
 	return 0;
 }
@@ -527,7 +527,7 @@ static int kvm_s390_set_tod_low(struct kvm *kvm, struct kvm_device_attr *attr)
 		return -EFAULT;
 
 	kvm_s390_set_tod_clock(kvm, gtod);
-	VM_EVENT(kvm, 3, "SET: TOD base: 0x%llx\n", gtod);
+	VM_EVENT(kvm, 3, "SET: TOD base: 0x%llx", gtod);
 	return 0;
 }
 
@@ -559,7 +559,7 @@ static int kvm_s390_get_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)
 	if (copy_to_user((void __user *)attr->addr, &gtod_high,
 					 sizeof(gtod_high)))
 		return -EFAULT;
-	VM_EVENT(kvm, 3, "QUERY: TOD extension: 0x%x\n", gtod_high);
+	VM_EVENT(kvm, 3, "QUERY: TOD extension: 0x%x", gtod_high);
 
 	return 0;
 }
@@ -571,7 +571,7 @@ static int kvm_s390_get_tod_low(struct kvm *kvm, struct kvm_device_attr *attr)
 	gtod = kvm_s390_get_tod_clock_fast(kvm);
 	if (copy_to_user((void __user *)attr->addr, &gtod, sizeof(gtod)))
 		return -EFAULT;
-	VM_EVENT(kvm, 3, "QUERY: TOD base: 0x%llx\n", gtod);
+	VM_EVENT(kvm, 3, "QUERY: TOD base: 0x%llx", gtod);
 
 	return 0;
 }
@@ -1098,7 +1098,9 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	if (!kvm->arch.sca)
 		goto out_err;
 	spin_lock(&kvm_lock);
-	sca_offset = (sca_offset + 16) & 0x7f0;
+	sca_offset += 16;
+	if (sca_offset + sizeof(struct sca_block) > PAGE_SIZE)
+		sca_offset = 0;
 	kvm->arch.sca = (struct sca_block *) ((char *) kvm->arch.sca + sca_offset);
 	spin_unlock(&kvm_lock);