drm/i915: Use VMA as the primary tracker for semaphore page

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1471254551-25805-23-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_debugfs.c

@@ -3189,7 +3189,7 @@ static int i915_semaphore_status(struct seq_file *m, void *unused)
 		struct page *page;
 		uint64_t *seqno;
 
-		page = i915_gem_object_get_page(dev_priv->semaphore_obj, 0);
+		page = i915_gem_object_get_page(dev_priv->semaphore->obj, 0);
 
 		seqno = (uint64_t *)kmap_atomic(page);
 		for_each_engine_id(engine, dev_priv, id) {

drivers/gpu/drm/i915/i915_drv.h

@@ -733,7 +733,7 @@ struct drm_i915_error_state {
 	u64 fence[I915_MAX_NUM_FENCES];
 	struct intel_overlay_error_state *overlay;
 	struct intel_display_error_state *display;
-	struct drm_i915_error_object *semaphore_obj;
+	struct drm_i915_error_object *semaphore;
 
 	struct drm_i915_error_engine {
 		int engine_id;
@@ -1750,7 +1750,7 @@ struct drm_i915_private {
 	struct pci_dev *bridge_dev;
 	struct i915_gem_context *kernel_context;
 	struct intel_engine_cs engine[I915_NUM_ENGINES];
-	struct drm_i915_gem_object *semaphore_obj;
+	struct i915_vma *semaphore;
 	u32 next_seqno;
 
 	struct drm_dma_handle *status_page_dmah;

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -549,7 +549,7 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
 		}
 	}
 
-	if ((obj = error->semaphore_obj)) {
+	if ((obj = error->semaphore)) {
 		err_printf(m, "Semaphore page = 0x%08x\n",
 			   lower_32_bits(obj->gtt_offset));
 		for (elt = 0; elt < PAGE_SIZE/16; elt += 4) {
@@ -640,7 +640,7 @@ static void i915_error_state_free(struct kref *error_ref)
 		kfree(ee->waiters);
 	}
 
-	i915_error_object_free(error->semaphore_obj);
+	i915_error_object_free(error->semaphore);
 
 	for (i = 0; i < ARRAY_SIZE(error->active_bo); i++)
 		kfree(error->active_bo[i]);
@@ -876,7 +876,7 @@ static void gen8_record_semaphore_state(struct drm_i915_error_state *error,
 	struct intel_engine_cs *to;
 	enum intel_engine_id id;
 
-	if (!error->semaphore_obj)
+	if (!error->semaphore)
 		return;
 
 	for_each_engine_id(to, dev_priv, id) {
@@ -889,7 +889,7 @@ static void gen8_record_semaphore_state(struct drm_i915_error_state *error,
 
 		signal_offset =
 			(GEN8_SIGNAL_OFFSET(engine, id) & (PAGE_SIZE - 1)) / 4;
-		tmp = error->semaphore_obj->pages[0];
+		tmp = error->semaphore->pages[0];
 		idx = intel_engine_sync_index(engine, to);
 
 		ee->semaphore_mboxes[idx] = tmp[signal_offset];
@@ -1061,11 +1061,9 @@ static void i915_gem_record_rings(struct drm_i915_private *dev_priv,
 	struct drm_i915_gem_request *request;
 	int i, count;
 
-	if (dev_priv->semaphore_obj) {
-		error->semaphore_obj =
-			i915_error_ggtt_object_create(dev_priv,
-						      dev_priv->semaphore_obj);
-	}
+	error->semaphore =
+		i915_error_ggtt_object_create(dev_priv,
+					      dev_priv->semaphore->obj);
 
 	for (i = 0; i < I915_NUM_ENGINES; i++) {
 		struct intel_engine_cs *engine = &dev_priv->engine[i];

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -179,12 +179,16 @@ void intel_engine_init_seqno(struct intel_engine_cs *engine, u32 seqno)
 		if (HAS_VEBOX(dev_priv))
 			I915_WRITE(RING_SYNC_2(engine->mmio_base), 0);
 	}
-	if (dev_priv->semaphore_obj) {
-		struct drm_i915_gem_object *obj = dev_priv->semaphore_obj;
-		struct page *page = i915_gem_object_get_dirty_page(obj, 0);
-		void *semaphores = kmap(page);
+	if (dev_priv->semaphore) {
+		struct page *page = i915_vma_first_page(dev_priv->semaphore);
+		void *semaphores;
+
+		/* Semaphores are in noncoherent memory, flush to be safe */
+		semaphores = kmap(page);
 		memset(semaphores + GEN8_SEMAPHORE_OFFSET(engine->id, 0),
 		       0, I915_NUM_ENGINES * gen8_semaphore_seqno_size);
+		drm_clflush_virt_range(semaphores + GEN8_SEMAPHORE_OFFSET(engine->id, 0),
+				       I915_NUM_ENGINES * gen8_semaphore_seqno_size);
 		kunmap(page);
 	}
 	memset(engine->semaphore.sync_seqno, 0,

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -1257,12 +1257,14 @@ static int init_render_ring(struct intel_engine_cs *engine)
 static void render_ring_cleanup(struct intel_engine_cs *engine)
 {
 	struct drm_i915_private *dev_priv = engine->i915;
+	struct i915_vma *vma;
 
-	if (dev_priv->semaphore_obj) {
-		i915_gem_object_ggtt_unpin(dev_priv->semaphore_obj);
-		i915_gem_object_put(dev_priv->semaphore_obj);
-		dev_priv->semaphore_obj = NULL;
-	}
+	vma = fetch_and_zero(&dev_priv->semaphore);
+	if (!vma)
+		return;
+
+	i915_vma_unpin(vma);
+	i915_vma_put(vma);
 }
 
 static int gen8_rcs_signal(struct drm_i915_gem_request *req)
@@ -2523,30 +2525,30 @@ static void intel_ring_init_semaphores(struct drm_i915_private *dev_priv,
 	if (!i915.semaphores)
 		return;
 
-	if (INTEL_GEN(dev_priv) >= 8 && !dev_priv->semaphore_obj) {
+	if (INTEL_GEN(dev_priv) >= 8 && !dev_priv->semaphore) {
+		struct i915_vma *vma;
+
 		obj = i915_gem_object_create(&dev_priv->drm, 4096);
-		if (IS_ERR(obj)) {
-			DRM_ERROR("Failed to allocate semaphore bo. Disabling semaphores\n");
-			i915.semaphores = 0;
-		} else {
-			i915_gem_object_set_cache_level(obj, I915_CACHE_LLC);
-			ret = i915_gem_object_ggtt_pin(obj, NULL,
-						       0, 0, PIN_HIGH);
-			if (ret != 0) {
-				i915_gem_object_put(obj);
-				DRM_ERROR("Failed to pin semaphore bo. Disabling semaphores\n");
-				i915.semaphores = 0;
-			} else {
-				dev_priv->semaphore_obj = obj;
-			}
-		}
-	}
+		if (IS_ERR(obj))
+			goto err;
 
-	if (!i915.semaphores)
-		return;
+		vma = i915_vma_create(obj, &dev_priv->ggtt.base, NULL);
+		if (IS_ERR(vma))
+			goto err_obj;
+
+		ret = i915_gem_object_set_to_gtt_domain(obj, false);
+		if (ret)
+			goto err_obj;
+
+		ret = i915_vma_pin(vma, 0, 0, PIN_GLOBAL | PIN_HIGH);
+		if (ret)
+			goto err_obj;
+
+		dev_priv->semaphore = vma;
+	}
 
 	if (INTEL_GEN(dev_priv) >= 8) {
-		u64 offset = i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj);
+		u64 offset = dev_priv->semaphore->node.start;
 
 		engine->semaphore.sync_to = gen8_ring_sync_to;
 		engine->semaphore.signal = gen8_xcs_signal;
@@ -2613,6 +2615,14 @@ static void intel_ring_init_semaphores(struct drm_i915_private *dev_priv,
 			engine->semaphore.mbox.signal[i] = mbox_reg;
 		}
 	}
+
+	return;
+
+err_obj:
+	i915_gem_object_put(obj);
+err:
+	DRM_DEBUG_DRIVER("Failed to allocate space for semaphores, disabling\n");
+	i915.semaphores = 0;
 }
 
 static void intel_ring_init_irq(struct drm_i915_private *dev_priv,

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -57,10 +57,10 @@ struct intel_hw_status_page {
 #define GEN8_SEMAPHORE_OFFSET(__from, __to)			     \
 	(((__from) * I915_NUM_ENGINES  + (__to)) * gen8_semaphore_seqno_size)
 #define GEN8_SIGNAL_OFFSET(__ring, to)			     \
-	(i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
+	(dev_priv->semaphore->node.start + \
 	 GEN8_SEMAPHORE_OFFSET((__ring)->id, (to)))
 #define GEN8_WAIT_OFFSET(__ring, from)			     \
-	(i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
+	(dev_priv->semaphore->node.start + \
 	 GEN8_SEMAPHORE_OFFSET(from, (__ring)->id))
 
 enum intel_engine_hangcheck_action {