From e433715b116553892ecad8796018ae4b64304252 Mon Sep 17 00:00:00 2001 From: Oleksandr Tyshchenko Date: Wed, 5 Oct 2022 20:48:22 +0300 Subject: xen/virtio: Fix n_pages calculation in xen_grant_dma_map(unmap)_page() Take page offset into the account when calculating the number of pages to be granted. Fixes: d6aca3504c7d ("xen/grant-dma-ops: Add option to restrict memory access under Xen") Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Stefano Stabellini Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20221005174823.1800761-2-olekstysh@gmail.com Signed-off-by: Juergen Gross --- drivers/xen/grant-dma-ops.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index 8973fc1e9ccc..1998d0e8ce82 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -153,7 +153,7 @@ static dma_addr_t xen_grant_dma_map_page(struct device *dev, struct page *page, unsigned long attrs) { struct xen_grant_dma_data *data; - unsigned int i, n_pages = PFN_UP(size); + unsigned int i, n_pages = PFN_UP(offset + size); grant_ref_t grant; dma_addr_t dma_handle; @@ -185,7 +185,8 @@ static void xen_grant_dma_unmap_page(struct device *dev, dma_addr_t dma_handle, unsigned long attrs) { struct xen_grant_dma_data *data; - unsigned int i, n_pages = PFN_UP(size); + unsigned long offset = dma_handle & (PAGE_SIZE - 1); + unsigned int i, n_pages = PFN_UP(offset + size); grant_ref_t grant; if (WARN_ON(dir == DMA_NONE)) -- cgit v1.2.3