On Mon, May 17, 2021 at 06:06:44PM +0100, Matthew Auld wrote: > > Looks like it is caused by the validation failure then. Which means the > > existing code is doing something wrong in its choice of the page > > protection bit. I really need help from the i915 maintainers here.. > > AFAIK there are two users of remap_io_sg, the first is our shmem > objects(see i915_gem_shmem.c), and for these we support UC, WC, and WB > mmap modes for userspace. The other user is device local-memory > objects(VRAM), and for this one we have an actual io_mapping which is > allocated as WC, and IIRC this should only be mapped as WC for the > mmap mode, but normal userspace can't hit this path yet. The only caller in current mainline is vm_fault_cpu in i915_gem_mman.c. Is that device local? > What do we need to do here? It sounds like shmem backed objects are > allocated as WB for the pages underneath, but i915 allows mapping them > as UC/WC which trips up this track_pfn thing? To me the warnings looks like system memory is mapped with the wrong permissions, yes. If you want to map it as UC/WC the right set_memory_* needs to be used on the kernel mapping as well to ensure that the attributes don't conflict. _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
