From f1225ee4c8fcf09afaa199b8b1f0450f38b8cd11 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 19 Jan 2017 10:39:09 -0800 Subject: [PATCH] swiotlb-xen: update dev_addr after swapping pages In xen_swiotlb_map_page and xen_swiotlb_map_sg_attrs, if the original page is not suitable, we swap it for another page from the swiotlb pool. In these cases, we don't update the previously calculated dma address for the page before calling xen_dma_map_page. Thus, we end up calling xen_dma_map_page passing the wrong dev_addr, resulting in xen_dma_map_page mistakenly assuming that the page is foreign when it is local. Fix the bug by updating dev_addr appropriately. This change has no effect on x86, because xen_dma_map_page is a stub there. Signed-off-by: Stefano Stabellini Signed-off-by: Pooya Keshavarzi Tested-by: Pooya Keshavarzi Reviewed-by: Boris Ostrovsky Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/swiotlb-xen.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index f905d6eeb048..f8afc6dcc29f 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -414,9 +414,9 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, if (map == SWIOTLB_MAP_ERROR) return DMA_ERROR_CODE; + dev_addr = xen_phys_to_bus(map); xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT), dev_addr, map & ~PAGE_MASK, size, dir, attrs); - dev_addr = xen_phys_to_bus(map); /* * Ensure that the address returned is DMA'ble @@ -575,13 +575,14 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, sg_dma_len(sgl) = 0; return 0; } + dev_addr = xen_phys_to_bus(map); xen_dma_map_page(hwdev, pfn_to_page(map >> PAGE_SHIFT), dev_addr, map & ~PAGE_MASK, sg->length, dir, attrs); - sg->dma_address = xen_phys_to_bus(map); + sg->dma_address = dev_addr; } else { /* we are not interested in the dma_addr returned by * xen_dma_map_page, only in the potential cache flushes executed -- 2.20.1