Commit ec671737 authored by Christian König's avatar Christian König Committed by Alex Deucher
Browse files

drm/amdgpu: add graceful VM fault handling v3 



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: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarFelix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent b65709a9

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

+73 −0
Original line number Diff line number Diff line
@@ -3126,3 +3126,76 @@ 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;

}

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c

+4 −0
Original line number Diff line number Diff line
@@ -380,6 +380,10 @@ 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

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