diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 2b01bfbce3ea..9bb700d25ccb 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1652,6 +1652,34 @@ static unsigned long vma_to_pfn(struct vm_area_struct *vma)
 	return (pci_resource_start(vdev->pdev, index) >> PAGE_SHIFT) + pgoff;
 }
 
+vm_fault_t vfio_pci_vmf_insert_pfn(struct vfio_pci_core_device *vdev,
+				   struct vm_fault *vmf,
+				   unsigned long pfn,
+				   unsigned int order)
+{
+	lockdep_assert_held_read(&vdev->memory_lock);
+
+	if (vdev->pm_runtime_engaged || !__vfio_pci_memory_enabled(vdev))
+		return VM_FAULT_SIGBUS;
+
+	switch (order) {
+	case 0:
+		return vmf_insert_pfn(vmf->vma, vmf->address, pfn);
+#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
+	case PMD_ORDER:
+		return vmf_insert_pfn_pmd(vmf, pfn, false);
+#endif
+#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP
+	case PUD_ORDER:
+		return vmf_insert_pfn_pud(vmf, pfn, false);
+		break;
+#endif
+	default:
+		return VM_FAULT_FALLBACK;
+	}
+}
+EXPORT_SYMBOL_GPL(vfio_pci_vmf_insert_pfn);
+
 static vm_fault_t vfio_pci_mmap_huge_fault(struct vm_fault *vmf,
 					   unsigned int order)
 {
@@ -1660,41 +1688,13 @@ static vm_fault_t vfio_pci_mmap_huge_fault(struct vm_fault *vmf,
 	unsigned long addr = vmf->address & ~((PAGE_SIZE << order) - 1);
 	unsigned long pgoff = (addr - vma->vm_start) >> PAGE_SHIFT;
 	unsigned long pfn = vma_to_pfn(vma) + pgoff;
-	vm_fault_t ret = VM_FAULT_SIGBUS;
+	vm_fault_t ret = VM_FAULT_FALLBACK;
 
-	if (order && (addr < vma->vm_start ||
-		      addr + (PAGE_SIZE << order) > vma->vm_end ||
-		      pfn & ((1 << order) - 1))) {
-		ret = VM_FAULT_FALLBACK;
-		goto out;
+	if (is_aligned_for_order(vma, addr, pfn, order)) {
+		scoped_guard(rwsem_read, &vdev->memory_lock)
+			ret = vfio_pci_vmf_insert_pfn(vdev, vmf, pfn, order);
 	}
 
-	down_read(&vdev->memory_lock);
-
-	if (vdev->pm_runtime_engaged || !__vfio_pci_memory_enabled(vdev))
-		goto out_unlock;
-
-	switch (order) {
-	case 0:
-		ret = vmf_insert_pfn(vma, vmf->address, pfn);
-		break;
-#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
-	case PMD_ORDER:
-		ret = vmf_insert_pfn_pmd(vmf, pfn, false);
-		break;
-#endif
-#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP
-	case PUD_ORDER:
-		ret = vmf_insert_pfn_pud(vmf, pfn, false);
-		break;
-#endif
-	default:
-		ret = VM_FAULT_FALLBACK;
-	}
-
-out_unlock:
-	up_read(&vdev->memory_lock);
-out:
 	dev_dbg_ratelimited(&vdev->pdev->dev,
 			   "%s(,order = %d) BAR %ld page offset 0x%lx: 0x%x\n",
 			    __func__, order,
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index a1eddd55dab8..5569488ec4dc 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -170,6 +170,9 @@ ssize_t vfio_pci_core_read(struct vfio_device *core_vdev, char __user *buf,
 		size_t count, loff_t *ppos);
 ssize_t vfio_pci_core_write(struct vfio_device *core_vdev, const char __user *buf,
 		size_t count, loff_t *ppos);
+vm_fault_t vfio_pci_vmf_insert_pfn(struct vfio_pci_core_device *vdev,
+				   struct vm_fault *vmf, unsigned long pfn,
+				   unsigned int order);
 int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma);
 void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count);
 int vfio_pci_core_match(struct vfio_device *core_vdev, char *buf);
@@ -212,4 +215,14 @@ VFIO_IOREAD_DECLARATION(32)
 VFIO_IOREAD_DECLARATION(64)
 #endif
 
+static inline bool is_aligned_for_order(struct vm_area_struct *vma,
+					unsigned long addr,
+					unsigned long pfn,
+					unsigned int order)
+{
+	return !(order && (addr < vma->vm_start ||
+			   addr + (PAGE_SIZE << order) > vma->vm_end ||
+			   !IS_ALIGNED(pfn, 1 << order)));
+}
+
 #endif /* VFIO_PCI_CORE_H */