[PATCH v2] drm/amdkfd: make sure VM is ready for updating operations

[Felix Kuehling]

On 2024-04-11 4:11, Lang Yu wrote:
> When page table BOs were evicted but not validated before
> updating page tables, VM is still in evicting state,
> amdgpu_vm_update_range returns -EBUSY and
> restore_process_worker runs into a dead loop.
>
> v2: Split the BO validation and page table update into
> two separate loops in amdgpu_amdkfd_restore_process_bos. (Felix)
>    1.Validate BOs
>    2.Validate VM (and DMABuf attachments)
>    3.Update page tables for the BOs validated above
>
> Fixes: 2fdba514ad5a ("drm/amdgpu: Auto-validate DMABuf imports in compute VMs")
>
> Signed-off-by: Lang Yu <Lang.Yu at amd.com>

Reviewed-by: Felix Kuehling <felix.kuehling at amd.com>


> ---
>   .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 34 +++++++++++--------
>   1 file changed, 20 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> index 0ae9fd844623..e2c9e6ddb1d1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> @@ -2900,13 +2900,12 @@ int amdgpu_amdkfd_gpuvm_restore_process_bos(void *info, struct dma_fence __rcu *
>   
>   	amdgpu_sync_create(&sync_obj);
>   
> -	/* Validate BOs and map them to GPUVM (update VM page tables). */
> +	/* Validate BOs managed by KFD */
>   	list_for_each_entry(mem, &process_info->kfd_bo_list,
>   			    validate_list) {
>   
>   		struct amdgpu_bo *bo = mem->bo;
>   		uint32_t domain = mem->domain;
> -		struct kfd_mem_attachment *attachment;
>   		struct dma_resv_iter cursor;
>   		struct dma_fence *fence;
>   
> @@ -2931,6 +2930,25 @@ int amdgpu_amdkfd_gpuvm_restore_process_bos(void *info, struct dma_fence __rcu *
>   				goto validate_map_fail;
>   			}
>   		}
> +	}
> +
> +	if (failed_size)
> +		pr_debug("0x%lx/0x%lx in system\n", failed_size, total_size);
> +
> +	/* Validate PDs, PTs and evicted DMABuf imports last. Otherwise BO
> +	 * validations above would invalidate DMABuf imports again.
> +	 */
> +	ret = process_validate_vms(process_info, &exec.ticket);
> +	if (ret) {
> +		pr_debug("Validating VMs failed, ret: %d\n", ret);
> +		goto validate_map_fail;
> +	}
> +
> +	/* Update mappings managed by KFD. */
> +	list_for_each_entry(mem, &process_info->kfd_bo_list,
> +			    validate_list) {
> +		struct kfd_mem_attachment *attachment;
> +
>   		list_for_each_entry(attachment, &mem->attachments, list) {
>   			if (!attachment->is_mapped)
>   				continue;
> @@ -2947,18 +2965,6 @@ int amdgpu_amdkfd_gpuvm_restore_process_bos(void *info, struct dma_fence __rcu *
>   		}
>   	}
>   
> -	if (failed_size)
> -		pr_debug("0x%lx/0x%lx in system\n", failed_size, total_size);
> -
> -	/* Validate PDs, PTs and evicted DMABuf imports last. Otherwise BO
> -	 * validations above would invalidate DMABuf imports again.
> -	 */
> -	ret = process_validate_vms(process_info, &exec.ticket);
> -	if (ret) {
> -		pr_debug("Validating VMs failed, ret: %d\n", ret);
> -		goto validate_map_fail;
> -	}
> -
>   	/* Update mappings not managed by KFD */
>   	list_for_each_entry(peer_vm, &process_info->vm_list_head,
>   			vm_list_node) {