This should have been fixed by this commit in amd-staging-drm-next: https://lore.kernel.org/patchwork/patch/1392368/

commit b8aff1f3a0b3d8434f8ccf5d3017137c29aca77b Author: Felix Kuehling Felix.Kuehling@amd.com Date: Mon Mar 8 22:15:42 2021 -0500

drm/amdkfd: fix build error with AMD_IOMMU_V2=m

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.

Fixes: 64d1c3a43a6f ("drm/amdkfd: Centralize IOMMUv2 code and make it conditional") Reported-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Felix Kuehling Felix.Kuehling@amd.com Reviewed-by: Christian König christian.koenig@amd.com

Regards,   Felix

On 2021-04-08 7:04 p.m., David Niklas wrote:

Hello, (There are so many maintainers for kfd_iommu.c I feel like I'm spamming.)

When compiling for Linux version 5.11.12 using the AMDGPU GPU driver with HSA_AMD enabled, I get the below set of errors. To work around this, I need to change AMD_IOMMU_V2 from M to Y. This bug doesn't affect linux kernel version 5.6 as it requires AMD_IOMMU_V2 to by Y when HSA_AMD is enabled. I'd bisect and request the removal of the relevant patch, but it's possible that building the linux kernel should work this way and so a fix, not a patch removal, is what should be issued. I'm attaching my kernel config for 5.11.

Thanks, David

PS: I made an official bug report in case you'd prefer that: https://bugzilla.kernel.org/show_bug.cgi?id=212619

drivers/gpu/drm/amd/amdkfd/kfd_iommu.o: In function `kfd_iommu_bind_process_to_device': /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:120: undefined reference to `amd_iommu_bind_pasid' drivers/gpu/drm/amd/amdkfd/kfd_iommu.o: In function `kfd_iommu_unbind_process': /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:138: undefined reference to `amd_iommu_unbind_pasid' drivers/gpu/drm/amd/amdkfd/kfd_iommu.o: In function `kfd_iommu_suspend': /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:292: undefined reference to `amd_iommu_set_invalidate_ctx_cb' /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:293: undefined reference to `amd_iommu_set_invalid_ppr_cb' drivers/gpu/drm/amd/amdkfd/kfd_iommu.o: In function `kfd_iommu_resume': /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:312: undefined reference to `amd_iommu_init_device' /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:316: undefined reference to `amd_iommu_set_invalidate_ctx_cb' /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:318: undefined reference to `amd_iommu_set_invalid_ppr_cb' /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:323: undefined reference to `amd_iommu_set_invalidate_ctx_cb' /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:324: undefined reference to `amd_iommu_set_invalid_ppr_cb' /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:325: undefined reference to `amd_iommu_free_device' /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:232: undefined reference to `amd_iommu_bind_pasid' drivers/gpu/drm/amd/amdkfd/kfd_iommu.o: In function `kfd_iommu_suspend': /root/working/linux-5.11.12/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_iommu.c:294: undefined reference to `amd_iommu_free_device' Makefile:1166: recipe for target 'vmlinux' failed make: *** [vmlinux] Error 1