diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h
index 3c4926aa78f4..6f9ff7a69fa2 100644
--- a/arch/s390/include/asm/gmap.h
+++ b/arch/s390/include/asm/gmap.h
@@ -148,4 +148,5 @@ int gmap_mprotect_notify(struct gmap *, unsigned long start,
 
 void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long dirty_bitmap[4],
 			     unsigned long gaddr, unsigned long vmaddr);
+int gmap_mark_unmergeable(void);
 #endif /* _ASM_S390_GMAP_H */
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 87258bebb955..bf61f48e9a3d 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2234,6 +2234,12 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
 		if (r)
 			break;
 
+		down_write(&current->mm->mmap_sem);
+		r = gmap_mark_unmergeable();
+		up_write(&current->mm->mmap_sem);
+		if (r)
+			break;
+
 		r = kvm_s390_pv_init_vm(kvm, &cmd->rc, &cmd->rrc);
 		if (r)
 			break;
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index edcdca97e85e..7291452fe5f0 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2548,6 +2548,22 @@ int s390_enable_sie(void)
 }
 EXPORT_SYMBOL_GPL(s390_enable_sie);
 
+int gmap_mark_unmergeable(void)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+
+	for (vma = mm->mmap; vma; vma = vma->vm_next) {
+		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
+				MADV_UNMERGEABLE, &vma->vm_flags)) {
+			return -ENOMEM;
+		}
+	}
+	mm->def_flags &= ~VM_MERGEABLE;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
+
 /*
  * Enable storage key handling from now on and initialize the storage
  * keys with the default key.
@@ -2593,7 +2609,6 @@ static const struct mm_walk_ops enable_skey_walk_ops = {
 int s390_enable_skey(void)
 {
 	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma;
 	int rc = 0;
 
 	down_write(&mm->mmap_sem);
@@ -2601,16 +2616,11 @@ int s390_enable_skey(void)
 		goto out_up;
 
 	mm->context.uses_skeys = 1;
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
-		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
-				MADV_UNMERGEABLE, &vma->vm_flags)) {
-			mm->context.uses_skeys = 0;
-			rc = -ENOMEM;
-			goto out_up;
-		}
+	rc = gmap_mark_unmergeable();
+	if (rc) {
+		mm->context.uses_skeys = 0;
+		goto out_up;
 	}
-	mm->def_flags &= ~VM_MERGEABLE;
-
 	walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
 
 out_up: