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SubjectRe: [PATCH kernel v8 03/31] vfio: powerpc/spapr: Check that IOMMU page is fully contained by system page
On Fri, Apr 10, 2015 at 04:30:45PM +1000, Alexey Kardashevskiy wrote:
> This checks that the TCE table page size is not bigger that the size of
> a page we just pinned and going to put its physical address to the table.
>
> Otherwise the hardware gets unwanted access to physical memory between
> the end of the actual page and the end of the aligned up TCE page.
>
> Since compound_order() and compound_head() work correctly on non-huge
> pages, there is no need for additional check whether the page is huge.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

Only thing I'm not sure about is...

> + if (!tce_page_is_contained(page, tbl->it_page_shift)) {
> + ret = -EPERM;
> + break;

.. whether EPERM is the right error code.

--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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