xen: add a dma_addr_t dev_addr argument to xen_dma_map_page

dev_addr is the machine address of the page.

The new parameter can be used by the ARM and ARM64 implementations of
xen_dma_map_page to find out if the page is a local page (pfn == mfn) or
a foreign page (pfn != mfn).

dev_addr could be retrieved again from the physical address, using
pfn_to_mfn, but it requires accessing an rbtree. Since we already have
the dev_addr in our hands at the call site there is no need to get the
mfn twice.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/arm/include/asm/xen/page-coherent.h

@@ -29,8 +29,8 @@ static inline void xen_free_coherent_pages(struct device *hwdev, size_t size,
 }
 
 static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
-	     unsigned long offset, size_t size, enum dma_data_direction dir,
-	     struct dma_attrs *attrs)
+	     dma_addr_t dev_addr, unsigned long offset, size_t size,
+	     enum dma_data_direction dir, struct dma_attrs *attrs)
 {
 	__generic_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs);
 }

arch/arm64/include/asm/xen/page-coherent.h

@@ -20,8 +20,8 @@ static inline void xen_free_coherent_pages(struct device *hwdev, size_t size,
 }
 
 static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
-	     unsigned long offset, size_t size, enum dma_data_direction dir,
-	     struct dma_attrs *attrs)
+	     dma_addr_t dev_addr, unsigned long offset, size_t size,
+	     enum dma_data_direction dir, struct dma_attrs *attrs)
 {
 }
 

arch/x86/include/asm/xen/page-coherent.h

@@ -22,8 +22,8 @@ static inline void xen_free_coherent_pages(struct device *hwdev, size_t size,
 }
 
 static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
-	     unsigned long offset, size_t size, enum dma_data_direction dir,
-	     struct dma_attrs *attrs) { }
+	     dma_addr_t dev_addr, unsigned long offset, size_t size,
+	     enum dma_data_direction dir, struct dma_attrs *attrs) { }
 
 static inline void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
 		size_t size, enum dma_data_direction dir,

drivers/xen/swiotlb-xen.c

@@ -403,7 +403,7 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 		/* we are not interested in the dma_addr returned by
 		 * xen_dma_map_page, only in the potential cache flushes executed
 		 * by the function. */
-		xen_dma_map_page(dev, page, offset, size, dir, attrs);
+		xen_dma_map_page(dev, page, dev_addr, offset, size, dir, attrs);
 		return dev_addr;
 	}
 
@@ -417,7 +417,7 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 		return DMA_ERROR_CODE;
 
 	xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT),
-					map & ~PAGE_MASK, size, dir, attrs);
+					dev_addr, map & ~PAGE_MASK, size, dir, attrs);
 	dev_addr = xen_phys_to_bus(map);
 
 	/*
@@ -574,6 +574,7 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 				return 0;
 			}
 			xen_dma_map_page(hwdev, pfn_to_page(map >> PAGE_SHIFT),
+						dev_addr,
 						map & ~PAGE_MASK,
 						sg->length,
 						dir,
@@ -584,6 +585,7 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 			 * xen_dma_map_page, only in the potential cache flushes executed
 			 * by the function. */
 			xen_dma_map_page(hwdev, pfn_to_page(paddr >> PAGE_SHIFT),
+						dev_addr,
 						paddr & ~PAGE_MASK,
 						sg->length,
 						dir,