[Intel-gfx] [PATCH v2 3/3] 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)

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    | 39 +++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

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 abc2b7a6dc92..47a8d610af6e 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -2211,6 +2211,36 @@ static int gen8_configure_context(struct i915_gem_context *ctx,
 	return err;
 }
 
+static int gen12_emit_oar_config(struct intel_context *ce, bool enable)
+{
+	struct i915_request *rq;
+	u32 *cs;
+	int err = 0;
+
+	rq = i915_request_create(ce);
+	if (IS_ERR(rq))
+		return PTR_ERR(rq);
+
+	cs = intel_ring_begin(rq, 4);
+	if (IS_ERR(cs)) {
+		err = PTR_ERR(cs);
+		goto out;
+	}
+
+	*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);
+
+out:
+	i915_request_add(rq);
+
+	return err;
+}
+
 /*
  * Manages updating the per-context aspects of the OA stream
  * configuration across all contexts.
@@ -2425,6 +2455,15 @@ static int gen12_enable_metric_set(struct i915_perf_stream *stream)
 	if (ret)
 		return ret;
 
+	/*
+	 * For Gen12, performance counters are context
+	 * saved/restored. Only enable it for the context that
+	 * requested this.
+	 */
+	ret = gen12_emit_oar_config(stream->pinned_ctx, oa_config != NULL);
+	if (ret)
+		return ret;
+
 	return emit_oa_config(stream, oa_context(stream));
 }
 
-- 
2.20.1