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

["Christian König" <christian.koenig@amd.com>]

Am 10.03.21 um 23:13 schrieb Felix Kuehling:
> 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.

Reviewed-by: Christian König <christian.koenig@amd.com>

>
> 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__ */