drm/i915: Allocate kernel_contexts directly

Ignore the central i915->kernel_context for allocating an engine, as
that GEM context is being phased out. For internal clients, we just need
the per-engine logical state, so allocate it at the point of use.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190808110612.23539-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/Makefile

@@ -95,8 +95,6 @@ gt-y += \
 	gt/gen7_renderstate.o \
 	gt/gen8_renderstate.o \
 	gt/gen9_renderstate.o
-gt-$(CONFIG_DRM_I915_SELFTEST) += \
-	gt/mock_engine.o
 i915-y += $(gt-y)
 
 # GEM (Graphics Execution Management) code

drivers/gpu/drm/i915/gt/intel_engine_cs.c

@@ -707,26 +707,6 @@ static int measure_breadcrumb_dw(struct intel_engine_cs *engine)
 	return dw;
 }
 
-static int pin_context(struct i915_gem_context *ctx,
-		       struct intel_engine_cs *engine,
-		       struct intel_context **out)
-{
-	struct intel_context *ce;
-	int err;
-
-	ce = i915_gem_context_get_engine(ctx, engine->id);
-	if (IS_ERR(ce))
-		return PTR_ERR(ce);
-
-	err = intel_context_pin(ce);
-	intel_context_put(ce);
-	if (err)
-		return err;
-
-	*out = ce;
-	return 0;
-}
-
 void
 intel_engine_init_active(struct intel_engine_cs *engine, unsigned int subclass)
 {
@@ -748,6 +728,25 @@ intel_engine_init_active(struct intel_engine_cs *engine, unsigned int subclass)
 #endif
 }
 
+static struct intel_context *
+create_kernel_context(struct intel_engine_cs *engine)
+{
+	struct intel_context *ce;
+	int err;
+
+	ce = intel_context_create(engine->i915->kernel_context, engine);
+	if (IS_ERR(ce))
+		return ce;
+
+	err = intel_context_pin(ce);
+	if (err) {
+		intel_context_put(ce);
+		return ERR_PTR(err);
+	}
+
+	return ce;
+}
+
 /**
  * intel_engines_init_common - initialize cengine state which might require hw access
  * @engine: Engine to initialize.
@@ -761,22 +760,24 @@ intel_engine_init_active(struct intel_engine_cs *engine, unsigned int subclass)
  */
 int intel_engine_init_common(struct intel_engine_cs *engine)
 {
-	struct drm_i915_private *i915 = engine->i915;
+	struct intel_context *ce;
 	int ret;
 
 	engine->set_default_submission(engine);
 
-	/* We may need to do things with the shrinker which
+	/*
+	 * We may need to do things with the shrinker which
 	 * require us to immediately switch back to the default
 	 * context. This can cause a problem as pinning the
 	 * default context also requires GTT space which may not
 	 * be available. To avoid this we always pin the default
 	 * context.
 	 */
-	ret = pin_context(i915->kernel_context, engine,
-			  &engine->kernel_context);
-	if (ret)
-		return ret;
+	ce = create_kernel_context(engine);
+	if (IS_ERR(ce))
+		return PTR_ERR(ce);
+
+	engine->kernel_context = ce;
 
 	ret = measure_breadcrumb_dw(engine);
 	if (ret < 0)
@@ -787,7 +788,8 @@ int intel_engine_init_common(struct intel_engine_cs *engine)
 	return 0;
 
 err_unpin:
-	intel_context_unpin(engine->kernel_context);
+	intel_context_unpin(ce);
+	intel_context_put(ce);
 	return ret;
 }
 
@@ -812,6 +814,7 @@ void intel_engine_cleanup_common(struct intel_engine_cs *engine)
 		i915_gem_object_put(engine->default_state);
 
 	intel_context_unpin(engine->kernel_context);
+	intel_context_put(engine->kernel_context);
 	GEM_BUG_ON(!llist_empty(&engine->barrier_tasks));
 
 	intel_wa_list_free(&engine->ctx_wa_list);
@@ -1573,5 +1576,6 @@ intel_engine_find_active_request(struct intel_engine_cs *engine)
 }
 
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "mock_engine.c"
 #include "selftest_engine_cs.c"
 #endif

drivers/gpu/drm/i915/gt/mock_engine.c

@@ -286,25 +286,19 @@ struct intel_engine_cs *mock_engine(struct drm_i915_private *i915,
 
 int mock_engine_init(struct intel_engine_cs *engine)
 {
-	struct drm_i915_private *i915 = engine->i915;
-	int err;
+	struct intel_context *ce;
 
 	intel_engine_init_active(engine, ENGINE_MOCK);
 	intel_engine_init_breadcrumbs(engine);
 	intel_engine_init_execlists(engine);
 	intel_engine_init__pm(engine);
 	intel_engine_pool_init(&engine->pool);
 
-	engine->kernel_context =
-		i915_gem_context_get_engine(i915->kernel_context, engine->id);
-	if (IS_ERR(engine->kernel_context))
-		goto err_breadcrumbs;
-
-	err = intel_context_pin(engine->kernel_context);
-	intel_context_put(engine->kernel_context);
-	if (err)
+	ce = create_kernel_context(engine);
+	if (IS_ERR(ce))
 		goto err_breadcrumbs;
 
+	engine->kernel_context = ce;
 	return 0;
 
 err_breadcrumbs:
@@ -338,6 +332,7 @@ void mock_engine_free(struct intel_engine_cs *engine)
 	GEM_BUG_ON(timer_pending(&mock->hw_delay));
 
 	intel_context_unpin(engine->kernel_context);
+	intel_context_put(engine->kernel_context);
 
 	intel_engine_fini_breadcrumbs(engine);
 

drivers/gpu/drm/i915/gvt/scheduler.c

@@ -1229,7 +1229,7 @@ int intel_vgpu_setup_submission(struct intel_vgpu *vgpu)
 		INIT_LIST_HEAD(&s->workload_q_head[i]);
 		s->shadow[i] = ERR_PTR(-EINVAL);
 
-		ce = i915_gem_context_get_engine(ctx, i);
+		ce = intel_context_create(ctx, engine);
 		if (IS_ERR(ce)) {
 			ret = PTR_ERR(ce);
 			goto out_shadow_ctx;
@@ -1270,6 +1270,7 @@ int intel_vgpu_setup_submission(struct intel_vgpu *vgpu)
 			break;
 
 		intel_context_unpin(s->shadow[i]);
+		intel_context_put(s->shadow[i]);
 	}
 	i915_gem_context_put(ctx);
 	return ret;

drivers/gpu/drm/i915/i915_gem.c

@@ -1256,9 +1256,8 @@ int i915_gem_init_hw(struct drm_i915_private *i915)
 
 static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 {
+	struct i915_request *requests[I915_NUM_ENGINES] = {};
 	struct intel_engine_cs *engine;
-	struct i915_gem_context *ctx;
-	struct i915_gem_engines *e;
 	enum intel_engine_id id;
 	int err = 0;
 
@@ -1271,20 +1270,25 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 	 * from the same default HW values.
 	 */
 
-	ctx = i915_gem_context_create_kernel(i915, 0);
-	if (IS_ERR(ctx))
-		return PTR_ERR(ctx);
-
-	e = i915_gem_context_lock_engines(ctx);
-
 	for_each_engine(engine, i915, id) {
-		struct intel_context *ce = e->engines[id];
+		struct intel_context *ce;
 		struct i915_request *rq;
 
+		/* We must be able to switch to something! */
+		GEM_BUG_ON(!engine->kernel_context);
+		engine->serial++; /* force the kernel context switch */
+
+		ce = intel_context_create(i915->kernel_context, engine);
+		if (IS_ERR(ce)) {
+			err = PTR_ERR(ce);
+			goto out;
+		}
+
 		rq = intel_context_create_request(ce);
 		if (IS_ERR(rq)) {
 			err = PTR_ERR(rq);
-			goto err_active;
+			intel_context_put(ce);
+			goto out;
 		}
 
 		err = intel_engine_emit_ctx_wa(rq);
@@ -1305,26 +1309,33 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 			goto err_rq;
 
 err_rq:
+		requests[id] = i915_request_get(rq);
 		i915_request_add(rq);
 		if (err)
-			goto err_active;
+			goto out;
 	}
 
 	/* Flush the default context image to memory, and enable powersaving. */
 	if (!i915_gem_load_power_context(i915)) {
 		err = -EIO;
-		goto err_active;
+		goto out;
 	}
 
-	for_each_engine(engine, i915, id) {
-		struct intel_context *ce = e->engines[id];
-		struct i915_vma *state = ce->state;
+	for (id = 0; id < ARRAY_SIZE(requests); id++) {
+		struct i915_request *rq;
+		struct i915_vma *state;
 		void *vaddr;
 
-		if (!state)
+		rq = requests[id];
+		if (!rq)
 			continue;
 
-		GEM_BUG_ON(intel_context_is_pinned(ce));
+		/* We want to be able to unbind the state from the GGTT */
+		GEM_BUG_ON(intel_context_is_pinned(rq->hw_context));
+
+		state = rq->hw_context->state;
+		if (!state)
+			continue;
 
 		/*
 		 * As we will hold a reference to the logical state, it will
@@ -1336,43 +1347,49 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 		 */
 		err = i915_vma_unbind(state);
 		if (err)
-			goto err_active;
+			goto out;
 
 		i915_gem_object_lock(state->obj);
 		err = i915_gem_object_set_to_cpu_domain(state->obj, false);
 		i915_gem_object_unlock(state->obj);
 		if (err)
-			goto err_active;
+			goto out;
 
-		engine->default_state = i915_gem_object_get(state->obj);
-		i915_gem_object_set_cache_coherency(engine->default_state,
-						    I915_CACHE_LLC);
+		i915_gem_object_set_cache_coherency(state->obj, I915_CACHE_LLC);
 
 		/* Check we can acquire the image of the context state */
-		vaddr = i915_gem_object_pin_map(engine->default_state,
-						I915_MAP_FORCE_WB);
+		vaddr = i915_gem_object_pin_map(state->obj, I915_MAP_FORCE_WB);
 		if (IS_ERR(vaddr)) {
 			err = PTR_ERR(vaddr);
-			goto err_active;
+			goto out;
 		}
 
-		i915_gem_object_unpin_map(engine->default_state);
+		rq->engine->default_state = i915_gem_object_get(state->obj);
+		i915_gem_object_unpin_map(state->obj);
 	}
 
-out_ctx:
-	i915_gem_context_unlock_engines(ctx);
-	i915_gem_context_set_closed(ctx);
-	i915_gem_context_put(ctx);
-	return err;
-
-err_active:
+out:
 	/*
 	 * If we have to abandon now, we expect the engines to be idle
 	 * and ready to be torn-down. The quickest way we can accomplish
 	 * this is by declaring ourselves wedged.
 	 */
-	intel_gt_set_wedged(&i915->gt);
-	goto out_ctx;
+	if (err)
+		intel_gt_set_wedged(&i915->gt);
+
+	for (id = 0; id < ARRAY_SIZE(requests); id++) {
+		struct intel_context *ce;
+		struct i915_request *rq;
+
+		rq = requests[id];
+		if (!rq)
+			continue;
+
+		ce = rq->hw_context;
+		i915_request_put(rq);
+		intel_context_put(ce);
+	}
+	return err;
 }
 
 static int