Re: [PATCH v2 1/1] drm/amdkfd: fix build error with AMD_IOMMU_V2=m

[Felix Kuehling <felix.kuehling@amd.com>]

On 2021-03-09 11:50 a.m., Felix Kuehling 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.
>
> 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>
Ping. Can I get an R-b for this patch.

Thanks,
   Felix


> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_iommu.c | 6 ++++++
>   drivers/gpu/drm/amd/amdkfd/kfd_iommu.h | 9 +++++++--
>   2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_iommu.c b/drivers/gpu/drm/amd/amdkfd/kfd_iommu.c
> index 66bbca61e3ef..9318936aa805 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_iommu.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_iommu.c
> @@ -20,6 +20,10 @@
>    * OTHER DEALINGS IN THE SOFTWARE.
>    */
>   
> +#include <linux/kconfig.h>
> +
> +#if IS_REACHABLE(CONFIG_AMD_IOMMU_V2)
> +
>   #include <linux/printk.h>
>   #include <linux/device.h>
>   #include <linux/slab.h>
> @@ -355,3 +359,5 @@ int kfd_iommu_add_perf_counters(struct kfd_topology_device *kdev)
>   
>   	return 0;
>   }
> +
> +#endif
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_iommu.h b/drivers/gpu/drm/amd/amdkfd/kfd_iommu.h
> index dd23d9fdf6a8..afd420b01a0c 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_iommu.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_iommu.h
> @@ -23,7 +23,9 @@
>   #ifndef __KFD_IOMMU_H__
>   #define __KFD_IOMMU_H__
>   
> -#if defined(CONFIG_AMD_IOMMU_V2_MODULE) || defined(CONFIG_AMD_IOMMU_V2)
> +#include <linux/kconfig.h>
> +
> +#if IS_REACHABLE(CONFIG_AMD_IOMMU_V2)
>   
>   #define KFD_SUPPORT_IOMMU_V2
>   
> @@ -46,6 +48,9 @@ static inline int kfd_iommu_check_device(struct kfd_dev *kfd)
>   }
>   static inline int kfd_iommu_device_init(struct kfd_dev *kfd)
>   {
> +#if IS_MODULE(CONFIG_AMD_IOMMU_V2)
> +	WARN_ONCE(1, "iommu_v2 module is not usable by built-in KFD");
> +#endif
>   	return 0;
>   }
>   
> @@ -73,6 +78,6 @@ static inline int kfd_iommu_add_perf_counters(struct kfd_topology_device *kdev)
>   	return 0;
>   }
>   
> -#endif /* defined(CONFIG_AMD_IOMMU_V2) */
> +#endif /* IS_REACHABLE(CONFIG_AMD_IOMMU_V2) */
>   
>   #endif /* __KFD_IOMMU_H__ */