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

[Umesh Nerlige Ramappa]

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>
Fixes: 00a7f0d7155c ("drm/i915/tgl: Add perf support on TGL")
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 f20dda40b378..9fef7b57520f 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -2722,7 +2722,8 @@ 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;
 	}
@@ -2754,7 +2755,7 @@ 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;
-- 
2.20.1