Re: [PATCH v3] drm/amdgpu: flush TLB if valid PDE turns into PTE

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 13.05.21 um 19:19 schrieb Felix Kuehling:
> Am 2021-05-13 um 12:58 p.m. schrieb Philip Yang:
>> Mapping huge page, 2MB aligned address with 2MB size, uses PDE0 as PTE.
>> If previously valid PDE0, PDE0.V=1 and PDE0.P=0 turns into PTE, this
>> requires TLB flush, otherwise page table walker will not read updated
>> PDE0.
>>
>> Change page table update mapping to return table_freed flag to indicate
>> the previously valid PDE may have turned into a PTE if page table is
>> freed.
>>
>> Signed-off-by: Philip Yang <Philip.Yang@amd.com>
> Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>

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

>
>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 14 ++++++++++----
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h |  7 ++++++-
>>   drivers/gpu/drm/amd/amdkfd/kfd_svm.c   | 13 +++++++++++--
>>   3 files changed, 27 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> index 3dcdcc9ff522..7e4c60a90eee 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> @@ -1583,6 +1583,7 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params,
>>   			while (cursor.pfn < frag_start) {
>>   				amdgpu_vm_free_pts(adev, params->vm, &cursor);
>>   				amdgpu_vm_pt_next(adev, &cursor);
>> +				params->table_freed = true;
>>   			}
>>   
>>   		} else if (frag >= shift) {
>> @@ -1610,6 +1611,7 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params,
>>    * @nodes: array of drm_mm_nodes with the MC addresses
>>    * @pages_addr: DMA addresses to use for mapping
>>    * @fence: optional resulting fence
>> + * @table_freed: return true if page table is freed
>>    *
>>    * Fill in the page table entries between @start and @last.
>>    *
>> @@ -1624,7 +1626,8 @@ int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
>>   				uint64_t flags, uint64_t offset,
>>   				struct drm_mm_node *nodes,
>>   				dma_addr_t *pages_addr,
>> -				struct dma_fence **fence)
>> +				struct dma_fence **fence,
>> +				bool *table_freed)
>>   {
>>   	struct amdgpu_vm_update_params params;
>>   	enum amdgpu_sync_mode sync_mode;
>> @@ -1736,6 +1739,9 @@ int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
>>   
>>   	r = vm->update_funcs->commit(&params, fence);
>>   
>> +	if (table_freed)
>> +		*table_freed = params.table_freed;
>> +
>>   error_unlock:
>>   	amdgpu_vm_eviction_unlock(vm);
>>   	return r;
>> @@ -1879,7 +1885,7 @@ int amdgpu_vm_bo_update(struct amdgpu_device *adev, struct amdgpu_bo_va *bo_va,
>>   						resv, mapping->start,
>>   						mapping->last, update_flags,
>>   						mapping->offset, nodes,
>> -						pages_addr, last_update);
>> +						pages_addr, last_update, NULL);
>>   		if (r)
>>   			return r;
>>   	}
>> @@ -2090,7 +2096,7 @@ int amdgpu_vm_clear_freed(struct amdgpu_device *adev,
>>   		r = amdgpu_vm_bo_update_mapping(adev, adev, vm, false, false,
>>   						resv, mapping->start,
>>   						mapping->last, init_pte_value,
>> -						0, NULL, NULL, &f);
>> +						0, NULL, NULL, &f, NULL);
>>   		amdgpu_vm_free_mapping(adev, vm, mapping, f);
>>   		if (r) {
>>   			dma_fence_put(f);
>> @@ -3428,7 +3434,7 @@ bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, u32 pasid,
>>   	}
>>   
>>   	r = amdgpu_vm_bo_update_mapping(adev, adev, vm, true, false, NULL, addr,
>> -					addr, flags, value, NULL, NULL,
>> +					addr, flags, value, NULL, NULL, NULL,
>>   					NULL);
>>   	if (r)
>>   		goto error_unlock;
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> index ea60ec122b51..e91288d637ce 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> @@ -231,6 +231,11 @@ struct amdgpu_vm_update_params {
>>   	 * @num_dw_left: number of dw left for the IB
>>   	 */
>>   	unsigned int num_dw_left;
>> +
>> +	/**
>> +	 * @table_freed: return true if page table is freed when updating
>> +	 */
>> +	bool table_freed;
>>   };
>>   
>>   struct amdgpu_vm_update_funcs {
>> @@ -404,7 +409,7 @@ int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
>>   				uint64_t flags, uint64_t offset,
>>   				struct drm_mm_node *nodes,
>>   				dma_addr_t *pages_addr,
>> -				struct dma_fence **fence);
>> +				struct dma_fence **fence, bool *free_table);
>>   int amdgpu_vm_bo_update(struct amdgpu_device *adev,
>>   			struct amdgpu_bo_va *bo_va,
>>   			bool clear);
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> index b665e9ff77e3..a518ad26ceec 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> @@ -1084,7 +1084,7 @@ svm_range_unmap_from_gpu(struct amdgpu_device *adev, struct amdgpu_vm *vm,
>>   
>>   	return amdgpu_vm_bo_update_mapping(adev, adev, vm, false, true, NULL,
>>   					   start, last, init_pte_value, 0,
>> -					   NULL, NULL, fence);
>> +					   NULL, NULL, fence, NULL);
>>   }
>>   
>>   static int
>> @@ -1137,6 +1137,7 @@ svm_range_map_to_gpu(struct amdgpu_device *adev, struct amdgpu_vm *vm,
>>   		     struct amdgpu_device *bo_adev, struct dma_fence **fence)
>>   {
>>   	struct amdgpu_bo_va bo_va;
>> +	bool table_freed = false;
>>   	uint64_t pte_flags;
>>   	int r = 0;
>>   
>> @@ -1159,7 +1160,8 @@ svm_range_map_to_gpu(struct amdgpu_device *adev, struct amdgpu_vm *vm,
>>   					prange->mapping.offset,
>>   					prange->ttm_res ?
>>   						prange->ttm_res->mm_node : NULL,
>> -					dma_addr, &vm->last_update);
>> +					dma_addr, &vm->last_update,
>> +					&table_freed);
>>   	if (r) {
>>   		pr_debug("failed %d to map to gpu 0x%lx\n", r, prange->start);
>>   		goto out;
>> @@ -1175,6 +1177,13 @@ svm_range_map_to_gpu(struct amdgpu_device *adev, struct amdgpu_vm *vm,
>>   	if (fence)
>>   		*fence = dma_fence_get(vm->last_update);
>>   
>> +	if (table_freed) {
>> +		struct kfd_process *p;
>> +
>> +		p = container_of(prange->svms, struct kfd_process, svms);
>> +		amdgpu_amdkfd_flush_gpu_tlb_pasid((struct kgd_dev *)adev,
>> +						  p->pasid);
>> +	}
>>   out:
>>   	prange->mapping.bo_va = NULL;
>>   	return r;
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