Next step towards HMM support. For now just silence the retry fault and
optionally redirect the request to the dummy page.
v2: make sure the VM is not destroyed while we handle the fault.
v3: fix VM destroy check, cleanup comments
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 73 ++++++++++++++++++++++++++
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 2 +
drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 4 ++
3 files changed, 79 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index db13ddd70a8d..48349e4f0701 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -3125,3 +3125,76 @@ void amdgpu_vm_set_task_info(struct amdgpu_vm *vm)
}
}
}
+
+/**
+ * amdgpu_vm_handle_fault - graceful handling of VM faults.
+ * @adev: amdgpu device pointer
+ * @pasid: PASID of the VM
+ * @addr: Address of the fault
+ *
+ * Try to gracefully handle a VM fault. Return true if the fault was handled and
+ * shouldn't be reported any more.
+ */
+bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, unsigned int pasid,
+ uint64_t addr)
+{
+ struct amdgpu_bo *root;
+ uint64_t value, flags;
+ struct amdgpu_vm *vm;
+ long r;
+
+ spin_lock(&adev->vm_manager.pasid_lock);
+ vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
+ if (vm)
+ root = amdgpu_bo_ref(vm->root.base.bo);
+ else
+ root = NULL;
+ spin_unlock(&adev->vm_manager.pasid_lock);
+
+ if (!root)
+ return false;
+
+ r = amdgpu_bo_reserve(root, true);
+ if (r)
+ goto error_unref;
+
+ /* Double check that the VM still exists */
+ spin_lock(&adev->vm_manager.pasid_lock);
+ vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
+ if (vm && vm->root.base.bo != root)
+ vm = NULL;
+ spin_unlock(&adev->vm_manager.pasid_lock);
+ if (!vm)
+ goto error_unlock;
+
+ addr /= AMDGPU_GPU_PAGE_SIZE;
+ flags = AMDGPU_PTE_VALID | AMDGPU_PTE_SNOOPED |
+ AMDGPU_PTE_SYSTEM;
+
+ if (amdgpu_vm_fault_stop == AMDGPU_VM_FAULT_STOP_NEVER) {
+ /* Redirect the access to the dummy page */
+ value = adev->dummy_page_addr;
+ flags |= AMDGPU_PTE_EXECUTABLE | AMDGPU_PTE_READABLE |
+ AMDGPU_PTE_WRITEABLE;
+ } else {
+ /* Let the hw retry silently on the PTE */
+ value = 0;
+ }
+
+ r = amdgpu_vm_bo_update_mapping(adev, vm, true, NULL, addr, addr + 1,
+ flags, value, NULL, NULL);
+ if (r)
+ goto error_unlock;
+
+ r = amdgpu_vm_update_pdes(adev, vm, true);
+
+error_unlock:
+ amdgpu_bo_unreserve(root);
+ if (r < 0)
+ DRM_ERROR("Can't handle page fault (%ld)\n", r);
+
+error_unref:
+ amdgpu_bo_unref(&root);
+
+ return false;
+}
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 0a97dc839f3b..4dbbe1b6b413 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -413,6 +413,8 @@ void amdgpu_vm_check_compute_bug(struct amdgpu_device *adev);
void amdgpu_vm_get_task_info(struct amdgpu_device *adev, unsigned int pasid,
struct amdgpu_task_info *task_info);
+bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, unsigned int pasid,
+ uint64_t addr);
void amdgpu_vm_set_task_info(struct amdgpu_vm *vm);
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
index 0d06c7901d26..ad19c8194a73 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
@@ -375,6 +375,10 @@ static int gmc_v9_0_process_interrupt(struct amdgpu_device *adev,
}
/* If it's the first fault for this address, process it normally */
+ if (retry_fault && !in_interrupt() &&
+ amdgpu_vm_handle_fault(adev, entry->pasid, addr))
+ return 1; /* This also prevents sending it to KFD */
+
if (!amdgpu_sriov_vf(adev)) {
/*
* Issue a dummy read to wait for the status register to
--
2.17.1
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