[Intel-gfx] [PATCH v3 1/2] drm/i915/perf: Allow non-privileged access when OA buffer is not sampled

[Lionel Landwerlin]

On 19/11/2019 00:24, Umesh Nerlige Ramappa wrote:
> SAMPLE_OA_REPORT enables sampling of OA reports from the OA buffer.
> Since reports from OA buffer had system wide visibility, collecting
> samples from the OA buffer was a privileged operation on previous
> platforms. Prior to TGL, it was also necessary to sample the OA buffer
> to normalize reports from MI REPORT PERF COUNT.
>
> TGL has a dedicated OAR unit to sample perf reports for a specific
> render context. This removes the necessity to sample OA buffer.
>
> - If not sampling the OA buffer, allow non-privileged access. An earlier
>    patch allows the non-privilege access:
>    https://patchwork.freedesktop.org/patch/337716/?series=68582&rev=1
> - Clear up the path for non-privileged access in this patch
>
> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>

> ---
>   drivers/gpu/drm/i915/i915_perf.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index 608e6c3f3c1a..ca58502a67d8 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -2720,7 +2720,8 @@ static int i915_oa_stream_init(struct i915_perf_stream *stream,
>   		return -EINVAL;
>   	}
>   
> -	if (!(props->sample_flags & SAMPLE_OA_REPORT)) {
> +	if (!(props->sample_flags & SAMPLE_OA_REPORT) &&
> +	    (INTEL_GEN(perf->i915) < 12 || !stream->ctx)) {
>   		DRM_DEBUG("Only OA report sampling supported\n");
>   		return -EINVAL;
>   	}
> @@ -2752,7 +2753,7 @@ static int i915_oa_stream_init(struct i915_perf_stream *stream,
>   
>   	format_size = perf->oa_formats[props->oa_format].size;
>   
> -	stream->sample_flags |= SAMPLE_OA_REPORT;
> +	stream->sample_flags = props->sample_flags;
>   	stream->sample_size += format_size;
>   
>   	stream->oa_buffer.format_size = format_size;