Messages in this thread | | | Date | Fri, 17 Jun 2022 14:58:56 -0700 | From | Nicolin Chen <> | Subject | Re: [RFT][PATCH v1 5/6] vfio/ccw: Add kmap_local_page() for memcpy |
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On Fri, Jun 17, 2022 at 01:44:30AM -0700, Christoph Hellwig wrote: > On Thu, Jun 16, 2022 at 04:52:11PM -0700, Nicolin Chen wrote: > > The pinned PFN list returned from vfio_pin_pages() is simply converted > > using page_to_pfn() without protection, so direct access via memcpy() > > will crash on S390 if the PFN is an IO PFN. Instead, the pages should > > be touched using kmap_local_page(). > > I don't see how this helps. kmap_local_page only works for either > pages in the kernel direct map or highmem, but not for memory that needs > to be ioremapped. And there is no highmem on s390.
Oh..I will discuss with Jason once he's back, to see if we should simply drop this change. Thanks!
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