[PATCH 11/15] drm/i915: Introduce execlist context status change notification

[Zhi Wang <zhi.a.wang@xxxxxxxxx>]

This patch introduces an approach to track the execlist context status
change.

GVT-g uses GVT context as the "shadow context". The content inside GVT
context will be copied back to guest after the context is idle. So GVT-g
has to know the status of the execlist context.

This function is configurable in the context creation service. Currently,
Only GVT-g will create the "status-change-notification" enabled GEM
context.

Signed-off-by: Zhi Wang <zhi.a.wang@xxxxxxxxx>
---
 drivers/gpu/drm/i915/i915_drv.h  |  5 +++++
 drivers/gpu/drm/i915/intel_lrc.c | 23 +++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_lrc.h |  5 +++++
 3 files changed, 33 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 7f050a3..1c9e865 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -884,6 +884,8 @@ struct intel_context {
 		bool initialised;
 		bool skip_init_context;
 		u32 ring_buffer_size;
+		bool enable_status_change_notification;
+		struct atomic_notifier_head status_notifier_head;
 	} engine[I915_NUM_ENGINES];
 	bool use_48bit_addressing_mode;
 
@@ -2403,6 +2405,9 @@ struct drm_i915_gem_request {
 
 	/** Execlists context hardware id. */
 	unsigned ctx_hw_id;
+
+	/** GVT workload **/
+	void *gvt_workload;
 };
 
 struct drm_i915_gem_request * __must_check
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 0a96d4a..aeaea2e 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -415,6 +415,19 @@ static void execlists_submit_requests(struct drm_i915_gem_request *rq0,
 	spin_unlock_irq(&dev_priv->uncore.lock);
 }
 
+static inline void execlists_context_status_change(
+		struct drm_i915_gem_request *req,
+		unsigned long status)
+{
+	if (!req->ctx->engine[req->engine->id].
+			enable_status_change_notification)
+		return;
+
+	atomic_notifier_call_chain(
+			&req->ctx->engine[req->engine->id].status_notifier_head,
+			status, req->gvt_workload);
+}
+
 static void execlists_context_unqueue(struct intel_engine_cs *engine)
 {
 	struct drm_i915_gem_request *req0 = NULL, *req1 = NULL;
@@ -450,6 +463,11 @@ static void execlists_context_unqueue(struct intel_engine_cs *engine)
 	if (unlikely(!req0))
 		return;
 
+	execlists_context_status_change(req0, CONTEXT_SCHEDULE_IN);
+
+	if (req1)
+		execlists_context_status_change(req1, CONTEXT_SCHEDULE_IN);
+
 	if (req0->elsp_submitted & engine->idle_lite_restore_wa) {
 		/*
 		 * WaIdleLiteRestore: make sure we never cause a lite restore
@@ -488,6 +506,8 @@ execlists_check_remove_request(struct intel_engine_cs *engine, u32 ctx_id)
 	if (--head_req->elsp_submitted > 0)
 		return 0;
 
+	execlists_context_status_change(head_req, CONTEXT_SCHEDULE_OUT);
+
 	list_del(&head_req->execlist_link);
 	i915_gem_request_unreference(head_req);
 
@@ -2541,6 +2561,9 @@ static int execlists_context_deferred_alloc(struct intel_context *ctx,
 	ctx->engine[engine->id].state = ctx_obj;
 	ctx->engine[engine->id].initialised = engine_initialised(ctx, engine);
 
+	if (ctx->engine[engine->id].enable_status_change_notification)
+		ATOMIC_INIT_NOTIFIER_HEAD(
+				&ctx->engine[engine->id].status_notifier_head);
 	return 0;
 
 error_ringbuf:
diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index 1afba03..98c94ee 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -57,6 +57,11 @@
 #define GEN8_CSB_READ_PTR(csb_status) \
 	(((csb_status) & GEN8_CSB_READ_PTR_MASK) >> 8)
 
+enum {
+	CONTEXT_SCHEDULE_IN = 0,
+	CONTEXT_SCHEDULE_OUT,
+};
+
 /* Logical Rings */
 int intel_logical_ring_alloc_request_extras(struct drm_i915_gem_request *request);
 int intel_logical_ring_reserve_space(struct drm_i915_gem_request *request);
-- 
1.9.1

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