[PATCH 2/3] drm/amdkfd: Update get_wave_state() for GFX10

[Felix Kuehling]

On 2019-11-11 6:25 p.m., Yong Zhao wrote:
> Given control stack is now in the userspace context save restore area
> on GFX10, the same as GFX8, it is not needed to copy it back to userspace.
>
> Change-Id: I063ddc3026eefa57713ec47b466a90f9bf9d49b8
> Signed-off-by: Yong Zhao <Yong.Zhao at amd.com>
Patches 1 and 2 are

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


Patch 3 should arguably not be part of this series, because it does not 
affect GFXv10.

Regards,
   Felix



> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v10.c | 14 +++++++++-----
>   1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v10.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v10.c
> index 4884cd6c65ce..954dc8ac4ff1 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v10.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v10.c
> @@ -251,18 +251,22 @@ static int get_wave_state(struct mqd_manager *mm, void *mqd,
>   {
>   	struct v10_compute_mqd *m;
>   
> -	/* Control stack is located one page after MQD. */
> -	void *mqd_ctl_stack = (void *)((uintptr_t)mqd + PAGE_SIZE);
> -
>   	m = get_mqd(mqd);
>   
> +	/* Control stack is written backwards, while workgroup context data
> +	 * is written forwards. Both starts from m->cp_hqd_cntl_stack_size.
> +	 * Current position is at m->cp_hqd_cntl_stack_offset and
> +	 * m->cp_hqd_wg_state_offset, respectively.
> +	 */
>   	*ctl_stack_used_size = m->cp_hqd_cntl_stack_size -
>   		m->cp_hqd_cntl_stack_offset;
>   	*save_area_used_size = m->cp_hqd_wg_state_offset -
>   		m->cp_hqd_cntl_stack_size;
>   
> -	if (copy_to_user(ctl_stack, mqd_ctl_stack, m->cp_hqd_cntl_stack_size))
> -		return -EFAULT;
> +	/* Control stack is not copied to user mode for GFXv10 because
> +	 * it's part of the context save area that is already
> +	 * accessible to user mode
> +	 */
>   
>   	return 0;
>   }