[Intel-gfx] [PATCH v2 2/3] drm/i915/perf: enable OAR context save/restore of performance counters

[Umesh Nerlige Ramappa]

From: Lionel Landwerlin <lionel.g.landwerlin at intel.com>

We want this so we can preempt performance queries and keep the system
responsive even when long running queries are ongoing. We avoid doing
it for all contexts.

v2: use LRI to modify context control (Chris)
v3: use MASKED_FIELD to program just the masked bits (Chris)
v4: reuse request created during emit_oa_config (Lionel)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_lrc.h |  1 +
 drivers/gpu/drm/i915/i915_perf.c    | 35 ++++++++++++++++++++++++++++-
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.h b/drivers/gpu/drm/i915/gt/intel_lrc.h
index 99dc576a4e25..b6daac712c9e 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.h
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.h
@@ -43,6 +43,7 @@ struct intel_engine_cs;
 #define	  CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT	(1 << 0)
 #define   CTX_CTRL_RS_CTX_ENABLE		(1 << 1)
 #define	  CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT	(1 << 2)
+#define	  GEN12_CTX_CTRL_OAR_CONTEXT_ENABLE	(1 << 8)
 #define RING_CONTEXT_STATUS_PTR(base)		_MMIO((base) + 0x3a0)
 #define RING_EXECLIST_SQ_CONTENTS(base)		_MMIO((base) + 0x510)
 #define RING_EXECLIST_CONTROL(base)		_MMIO((base) + 0x550)
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 91707558a0f5..ce97af484a32 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -1862,14 +1862,36 @@ get_oa_vma(struct i915_perf_stream *stream, struct i915_oa_config *oa_config)
 	return i915_vma_get(oa_bo->vma);
 }
 
+static int gen12_emit_oar_config(struct i915_request *rq,
+				 struct intel_context *ce,
+				 bool enable)
+{
+	u32 *cs;
+
+	cs = intel_ring_begin(rq, 4);
+	if (IS_ERR(cs))
+		return PTR_ERR(cs);
+
+	*cs++ = MI_LOAD_REGISTER_IMM(1);
+	*cs++ = i915_mmio_reg_offset(RING_CONTEXT_CONTROL(ce->engine->mmio_base));
+	*cs++ = _MASKED_FIELD(GEN12_CTX_CTRL_OAR_CONTEXT_ENABLE,
+			      enable ? GEN12_CTX_CTRL_OAR_CONTEXT_ENABLE : 0);
+	*cs++ = MI_NOOP;
+
+	intel_ring_advance(rq, cs);
+
+	return 0;
+}
+
 static int emit_oa_config(struct i915_perf_stream *stream,
 			  struct intel_context *ce)
 {
+	struct i915_oa_config *oa_config = stream->oa_config;
 	struct i915_request *rq;
 	struct i915_vma *vma;
 	int err;
 
-	vma = get_oa_vma(stream, stream->oa_config);
+	vma = get_oa_vma(stream, oa_config);
 	if (IS_ERR(vma))
 		return PTR_ERR(vma);
 
@@ -1891,6 +1913,17 @@ static int emit_oa_config(struct i915_perf_stream *stream,
 	if (err)
 		goto err_add_request;
 
+	/*
+	 * For Gen12, performance counters are context saved/restored.
+	 * Only enable it for the context that requested this.
+	 */
+	if (ce == stream->pinned_ctx && IS_GEN(stream->perf->i915, 12)) {
+		err = gen12_emit_oar_config(rq, ce, oa_config != NULL);
+		if (err)
+			goto err_add_request;
+
+	}
+
 	err = rq->engine->emit_bb_start(rq,
 					vma->node.start, 0,
 					I915_DISPATCH_SECURE);
-- 
2.20.1