Am 2021-03-09 um 3:58 a.m. schrieb Arnd Bergmann: > On Tue, Mar 9, 2021 at 4:23 AM Felix Kuehling <Felix.Kuehling@xxxxxxx> wrote: >> Using 'imply AMD_IOMMU_V2' does not guarantee that the driver can link >> against the exported functions. If the GPU driver is built-in but the >> IOMMU driver is a loadable module, the kfd_iommu.c file is indeed >> built but does not work: >> >> x86_64-linux-ld: drivers/gpu/drm/amd/amdkfd/kfd_iommu.o: in function `kfd_iommu_bind_process_to_device': >> kfd_iommu.c:(.text+0x516): undefined reference to `amd_iommu_bind_pasid' >> x86_64-linux-ld: drivers/gpu/drm/amd/amdkfd/kfd_iommu.o: in function `kfd_iommu_unbind_process': >> kfd_iommu.c:(.text+0x691): undefined reference to `amd_iommu_unbind_pasid' >> x86_64-linux-ld: drivers/gpu/drm/amd/amdkfd/kfd_iommu.o: in function `kfd_iommu_suspend': >> kfd_iommu.c:(.text+0x966): undefined reference to `amd_iommu_set_invalidate_ctx_cb' >> x86_64-linux-ld: kfd_iommu.c:(.text+0x97f): undefined reference to `amd_iommu_set_invalid_ppr_cb' >> x86_64-linux-ld: kfd_iommu.c:(.text+0x9a4): undefined reference to `amd_iommu_free_device' >> x86_64-linux-ld: drivers/gpu/drm/amd/amdkfd/kfd_iommu.o: in function `kfd_iommu_resume': >> kfd_iommu.c:(.text+0xa9a): undefined reference to `amd_iommu_init_device' >> x86_64-linux-ld: kfd_iommu.c:(.text+0xadc): undefined reference to `amd_iommu_set_invalidate_ctx_cb' >> x86_64-linux-ld: kfd_iommu.c:(.text+0xaff): undefined reference to `amd_iommu_set_invalid_ppr_cb' >> x86_64-linux-ld: kfd_iommu.c:(.text+0xc72): undefined reference to `amd_iommu_bind_pasid' >> x86_64-linux-ld: kfd_iommu.c:(.text+0xe08): undefined reference to `amd_iommu_set_invalidate_ctx_cb' >> x86_64-linux-ld: kfd_iommu.c:(.text+0xe26): undefined reference to `amd_iommu_set_invalid_ppr_cb' >> x86_64-linux-ld: kfd_iommu.c:(.text+0xe42): undefined reference to `amd_iommu_free_device' >> >> Use IS_REACHABLE to only build IOMMU-V2 support if the amd_iommu symbols >> are reachable by the amdkfd driver. Output a warning if they are not, >> because that may not be what the user was expecting. > This would fix the compile-time failure, but it still fails my CI > because you introduce > a compile-time warning. Can you change it into a runtime warning instead? Sure. > > Neither type of warning is likely to actually reach the person trying > to debug the > problem, so you still end up with machines that don't do what they should, > but I can live with the runtime warning as long as the build doesn't break. OK. > > I think the proper fix would be to not rely on custom hooks into a particular > IOMMU driver, but to instead ensure that the amdgpu driver can do everything > it needs through the regular linux/iommu.h interfaces. I realize this > is more work, > but I wonder if you've tried that, and why it didn't work out. As far as I know this hasn't been tried. I see that intel-iommu has its own SVM thing, which seems to be similar to what our IOMMUv2 does. I guess we'd have to abstract that into a common API. Regards, Felix > > Arnd _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
