KVM: arm64: Use find_vma_intersection()

find_vma_intersection() has been existing to search the intersected
vma. This uses the function where it's applicable, to simplify the
code.
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210316041126.81860-3-gshan@redhat.com

arch/arm64/kvm/mmu.c

@@ -421,10 +421,11 @@ static void stage2_unmap_memslot(struct kvm *kvm,
 	 *     +--------------------------------------------+
 	 */
 	do {
-		struct vm_area_struct *vma = find_vma(current->mm, hva);
+		struct vm_area_struct *vma;
 		hva_t vm_start, vm_end;
 
-		if (!vma || vma->vm_start >= reg_end)
+		vma = find_vma_intersection(current->mm, hva, reg_end);
+		if (!vma)
 			break;
 
 		/*
@@ -1329,10 +1330,11 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	 *     +--------------------------------------------+
 	 */
 	do {
-		struct vm_area_struct *vma = find_vma(current->mm, hva);
+		struct vm_area_struct *vma;
 		hva_t vm_start, vm_end;
 
-		if (!vma || vma->vm_start >= reg_end)
+		vma = find_vma_intersection(current->mm, hva, reg_end);
+		if (!vma)
 			break;
 
 		/*