On Thu, Oct 6, 2022 at 11:05 AM Juergen Gross wrote: > On 06.10.22 09:35, Xenia Ragiadakou wrote: > Hello Xenia, Juergen [sorry for the possible format issues] > > > > On 10/5/22 20:48, Oleksandr Tyshchenko wrote: > >> From: Oleksandr Tyshchenko > >> > >> Take page offset into the account when calculating the number of pages > >> to be granted. > >> > >> Signed-off-by: Oleksandr Tyshchenko > >> Fixes: d6aca3504c7d ("xen/grant-dma-ops: Add option to restrict memory > access > >> under Xen") > >> --- > >> drivers/xen/grant-dma-ops.c | 5 +++-- > >> 1 file changed, 3 insertions(+), 2 deletions(-) > >> > >> 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); > > > > Here, why do we use PFN_UP and not XEN_PFN_UP? > > Also, since the variable 'n_pages' seems to refer to the number of > grants > > (unless I got it all entirely wrong ...), wouldn't it be more suitable > to call > > explicitly gnttab_count_grant()? > > Good point. > +1 > > I think this will need another patch for switching grant-dma-ops.c to > use XEN_PAGE_SIZE and XEN_PAGE_SHIFT. > +1 I can create a separate patch for converting on top of this series, it would be nice to clarify one point. So I will convert PAGE_SIZE/PAGE_SHIFT to XEN_PAGE_SIZE/XEN_PAGE_SHIFT respectively (where appropriate). Should the PFN_UP be converted to XEN_PFN_UP *or* use gnttab_count_grant() explicitly? Personally I would prefer the former, but would also be ok with the latter. > > > Juergen > > -- Regards, Oleksandr Tyshchenko