[PATCH v6 5/5] drm/amdgpu: add support of debugfs for mqd information

[Christian König]

On 27.06.25 11:49, Sunil Khatri wrote:
> Add debugfs support for mqd for each queue of the client.
> 
> The address exposed to debugfs could be used to dump
> the mqd.
> 
> Signed-off-by: Sunil Khatri <sunil.khatri at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 52 +++++++++++++++++++++++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h |  1 +
>  2 files changed, 53 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> index 295e7186e156..115d53bc9a8d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> @@ -318,6 +318,9 @@ amdgpu_userq_destroy(struct drm_file *filp, int queue_id)
>  		amdgpu_bo_unreserve(queue->db_obj.obj);
>  	}
>  	amdgpu_bo_unref(&queue->db_obj.obj);
> +
> +	debugfs_remove_recursive(queue->debugfs_queue);
> +
>  	r = amdgpu_userq_unmap_helper(uq_mgr, queue);
>  	amdgpu_userq_cleanup(uq_mgr, queue, queue_id);
>  	mutex_unlock(&uq_mgr->userq_mutex);
> @@ -343,6 +346,46 @@ static int amdgpu_userq_priority_permit(struct drm_file *filp,
>  	return -EACCES;
>  }
>  
> +#if defined(CONFIG_DEBUG_FS)
> +static int amdgpu_mqd_info_read(struct seq_file *m, void *unused)
> +{
> +	struct amdgpu_usermode_queue *queue = m->private;
> +	struct amdgpu_bo *bo;
> +	int r;
> +
> +	if (!queue || !queue->mqd.obj)
> +		return -EINVAL;
> +
> +	bo = amdgpu_bo_ref(queue->mqd.obj);
> +	r = amdgpu_bo_reserve(bo, true);
> +	if (r) {
> +		amdgpu_bo_unref(&bo);
> +		return -EINVAL;
> +	}
> +
> +	seq_printf(m, "queue_type %d\n", queue->queue_type);
> +	seq_printf(m, "mqd_gpu_address: 0x%llx\n", amdgpu_bo_gpu_offset(queue->mqd.obj));
> +
> +	amdgpu_bo_unreserve(bo);
> +	amdgpu_bo_unref(&bo);
> +
> +	return 0;
> +}
> +
> +static int amdgpu_mqd_info_open(struct inode *inode, struct file *file)
> +{
> +	return single_open(file, amdgpu_mqd_info_read, inode->i_private);
> +}
> +
> +static const struct file_operations amdgpu_mqd_info_fops = {
> +	.owner = THIS_MODULE,
> +	.open = amdgpu_mqd_info_open,
> +	.read = seq_read,
> +	.llseek = seq_lseek,
> +	.release = single_release,
> +};
> +#endif

The #ifdef part is most likely better put into amdgpu_debugfs.c, but that adds more complexity. So for now that should be ok here as well.

If we get even more code here we might want to re-consider that. Feel free to add my rb.

Regards,
Christian.

> +
>  static int
>  amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args)
>  {
> @@ -352,6 +395,7 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args)
>  	const struct amdgpu_userq_funcs *uq_funcs;
>  	struct amdgpu_usermode_queue *queue;
>  	struct amdgpu_db_info db_info;
> +	char *queue_name;
>  	bool skip_map_queue;
>  	uint64_t index;
>  	int qid, r = 0;
> @@ -475,6 +519,14 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args)
>  		}
>  	}
>  
> +	queue_name = kasprintf(GFP_KERNEL, "queue-%d", qid);
> +	if (!queue_name)
> +		return -ENOMEM;
> +
> +	/* Queue dentry per client to hold MQD information   */
> +	queue->debugfs_queue = debugfs_create_dir(queue_name, filp->debugfs_client);
> +	debugfs_create_file("mqd_info", 0444, queue->debugfs_queue, queue, &amdgpu_mqd_info_fops);
> +	kfree(queue_name);
>  
>  	args->out.queue_id = qid;
>  
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h
> index ec040c2fd6c9..b1ca91b7cda4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h
> @@ -65,6 +65,7 @@ struct amdgpu_usermode_queue {
>  	struct dma_fence	*last_fence;
>  	u32			xcp_id;
>  	int			priority;
> +	struct dentry		*debugfs_queue;
>  };
>  
>  struct amdgpu_userq_funcs {