diff -u a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
--- a/drivers/xen/swiotlb-xen.c	2016-06-15 20:29:36.000000000 +0000
+++ b/drivers/xen/swiotlb-xen.c	2016-12-05 07:05:13.009992832 +0000
@@ -673,6 +673,13 @@
 }
 EXPORT_SYMBOL_GPL(xen_swiotlb_dma_supported);
 
+u64
+xen_swiotlb_get_required_mask(struct device *dev)
+{
+	return DMA_BIT_MASK(64);
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_get_required_mask);
+
 int
 xen_swiotlb_set_dma_mask(struct device *dev, u64 dma_mask)
 {
diff -u a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
--- a/include/linux/dma-mapping.h	2016-06-15 20:29:36.000000000 +0000
+++ b/include/linux/dma-mapping.h	2016-12-05 07:03:13.992601404 +0000
@@ -127,6 +127,7 @@
 	return dma_set_mask_and_coherent(dev, mask);
 }
 
+extern u64 dma_get_required_mask_from_max_pfn(struct device *dev);
 extern u64 dma_get_required_mask(struct device *dev);
 
 #ifndef set_arch_dma_coherent_ops
diff -u a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
--- a/include/xen/swiotlb-xen.h	2016-06-15 20:29:36.000000000 +0000
+++ b/include/xen/swiotlb-xen.h	2016-12-05 07:06:01.084938801 +0000
@@ -56,6 +56,10 @@
 extern int
 xen_swiotlb_dma_supported(struct device *hwdev, u64 mask);
 
+extern u64
+xen_swiotlb_get_required_mask(struct device *dev);
+
+
 extern int
 xen_swiotlb_set_dma_mask(struct device *dev, u64 dma_mask);
 #endif /* __LINUX_SWIOTLB_XEN_H */