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 <a...@arndb.de>
Signed-off-by: Felix Kuehling <felix.kuehl...@amd.com>
Ping. Can I get an R-b for this patch.

Reviewed-by: Christian König <christian.koe...@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__ */

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