On 26.09.2017 14:06, Thierry Reding wrote: > On Wed, Jul 05, 2017 at 07:29:46PM +0300, Dmitry Osipenko wrote: >> Due to a bug, multiple devices may try to map the same IOVA region. We can >> catch that case by checking that 'VALID' bit of the GART's page entry is >> unset prior to mapping of the page. > > Due to what bug? Sounds to me like access to the GART should be > exclusive, so that only a single driver can ever access it. >
Actually, there are a lot of peripherals behind the GART. But yes, probably we would use it exclusively for the GPU allocations. In a case of the GPU allocations there could be a bug in the allocation code (drm_mm_scan) that would cause re-mapping of the already mapped pages, we would be able to catch such a bug. -- Dmitry _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
