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: d6aca3504c ("xen/grant-dma-ops: Add option to restrict memory access under Xen")
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20221005174823.1800761-2-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Oleksandr Tyshchenko 2022-10-05 20:48:22 +03:00 committed by Juergen Gross
parent 06c62f8cbb
commit e433715b11

View File

@ -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))