KVM: s390: Fixes for 5.3

- prevent a user triggerable oops in the migration code
 - do not leak kernel stack content
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Merge tag 'kvm-s390-master-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-master

KVM: s390: Fixes for 5.3

- prevent a user triggerable oops in the migration code
- do not leak kernel stack content

arch/s390/kvm/interrupt.c

@@ -1961,6 +1961,16 @@ int s390int_to_s390irq(struct kvm_s390_interrupt *s390int,
 	case KVM_S390_MCHK:
 		irq->u.mchk.mcic = s390int->parm64;
 		break;
+	case KVM_S390_INT_PFAULT_INIT:
+		irq->u.ext.ext_params = s390int->parm;
+		irq->u.ext.ext_params2 = s390int->parm64;
+		break;
+	case KVM_S390_RESTART:
+	case KVM_S390_INT_CLOCK_COMP:
+	case KVM_S390_INT_CPU_TIMER:
+		break;
+	default:
+		return -EINVAL;
 	}
 	return 0;
 }

arch/s390/kvm/kvm-s390.c

@@ -1018,6 +1018,8 @@ static int kvm_s390_vm_start_migration(struct kvm *kvm)
 	/* mark all the pages in active slots as dirty */
 	for (slotnr = 0; slotnr < slots->used_slots; slotnr++) {
 		ms = slots->memslots + slotnr;
+		if (!ms->dirty_bitmap)
+			return -EINVAL;
 		/*
 		 * The second half of the bitmap is only used on x86,
 		 * and would be wasted otherwise, so we put it to good
@@ -4323,7 +4325,7 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp,
 	}
 	case KVM_S390_INTERRUPT: {
 		struct kvm_s390_interrupt s390int;
-		struct kvm_s390_irq s390irq;
+		struct kvm_s390_irq s390irq = {};
 
 		if (copy_from_user(&s390int, argp, sizeof(s390int)))
 			return -EFAULT;