Messages in this thread | | | Date | Sun, 19 Jun 2022 22:51:47 -0700 | From | Christoph Hellwig <> | Subject | Re: [RFT][PATCH v1 6/6] vfio: Replace phys_pfn with phys_page for vfio_pin_pages() |
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On Mon, Jun 20, 2022 at 12:00:46AM -0300, Jason Gunthorpe wrote: > On Fri, Jun 17, 2022 at 01:54:05AM -0700, Christoph Hellwig wrote: > > There is a bunch of code an comments in the iommu type1 code that > > suggest we can pin memory that is not page backed. > > AFAIK you can.. The whole follow_pte() mechanism allows raw PFNs to be > loaded into the type1 maps and the pin API will happily return > them. This happens in almost every qemu scenario because PCI MMIO BAR > memory ends up routed down this path.
Indeed, my read wasn't deep enough. Which means that we can't change the ->pin_pages interface to return a struct pages array, as we don't have one for those.
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