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

[Christian König <ckoenig.leichtzumerken@xxxxxxxxx>]

Am 12.05.21 um 14:34 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 free_table 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@xxxxxxx>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 17 +++++++++++------
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h |  2 +-
>   drivers/gpu/drm/amd/amdkfd/kfd_svm.c   | 12 ++++++++++--
>   3 files changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 3dcdcc9ff522..27418f9407f1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1457,7 +1457,7 @@ static void amdgpu_vm_fragment(struct amdgpu_vm_update_params *params,
>    */
>   static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params,
>   				 uint64_t start, uint64_t end,
> -				 uint64_t dst, uint64_t flags)
> +				 uint64_t dst, uint64_t flags, bool *free_table)

Please put that flag into the params structure instead.

Christian.

>   {
>   	struct amdgpu_device *adev = params->adev;
>   	struct amdgpu_vm_pt_cursor cursor;
> @@ -1583,6 +1583,8 @@ 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);
> +				if (free_table)
> +					*free_table = true;
>   			}
>   
>   		} else if (frag >= shift) {
> @@ -1610,6 +1612,7 @@ 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
> + * @free_table: return true if page table is freed
>    *
>    * Fill in the page table entries between @start and @last.
>    *
> @@ -1624,7 +1627,8 @@ 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 *free_table)
>   {
>   	struct amdgpu_vm_update_params params;
>   	enum amdgpu_sync_mode sync_mode;
> @@ -1721,7 +1725,8 @@ int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
>   		}
>   
>   		tmp = start + num_entries;
> -		r = amdgpu_vm_update_ptes(&params, start, tmp, addr, flags);
> +		r = amdgpu_vm_update_ptes(&params, start, tmp, addr, flags,
> +					  free_table);
>   		if (r)
>   			goto error_unlock;
>   
> @@ -1879,7 +1884,7 @@ 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 +2095,7 @@ 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 +3433,7 @@ 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..f61c20b70b79 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> @@ -404,7 +404,7 @@ 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..4f28052d44bf 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
> @@ -1137,12 +1137,15 @@ 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 free_table = false;
> +	struct kfd_process *p;
>   	uint64_t pte_flags;
>   	int r = 0;
>   
>   	pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms, prange->start,
>   		 prange->last);
>   
> +	p = container_of(prange->svms, struct kfd_process, svms);
>   	if (prange->svm_bo && prange->ttm_res) {
>   		bo_va.is_xgmi = amdgpu_xgmi_same_hive(adev, bo_adev);
>   		prange->mapping.bo_va = &bo_va;
> @@ -1159,7 +1162,8 @@ 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,
> +					&free_table);
>   	if (r) {
>   		pr_debug("failed %d to map to gpu 0x%lx\n", r, prange->start);
>   		goto out;
> @@ -1175,6 +1179,10 @@ svm_range_map_to_gpu(struct amdgpu_device *adev, struct amdgpu_vm *vm,
>   	if (fence)
>   		*fence = dma_fence_get(vm->last_update);
>   
> +	if (free_table)
> +		amdgpu_amdkfd_flush_gpu_tlb_pasid((struct kgd_dev *)adev,
> +						  p->pasid);
> +
>   out:
>   	prange->mapping.bo_va = NULL;
>   	return r;

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