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

[Christian König]

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@xxxxxxxx>
> > Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
> Ping. Can I get an R-b for this patch.

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

> 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__ */