1 files changed, 26 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index 010620b78202..ea90ab3e396e 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -20,6 +20,7 @@ static int __engine_unpark(struct intel_wakeref *wf)
 {
 	struct intel_engine_cs *engine =
 		container_of(wf, typeof(*engine), wakeref);
+	struct intel_context *ce;
 	void *map;
 
 	ENGINE_TRACE(engine, "\n");
@@ -34,6 +35,27 @@ static int __engine_unpark(struct intel_wakeref *wf)
 	if (!IS_ERR_OR_NULL(map))
 		engine->pinned_default_state = map;
 
+	/* Discard stale context state from across idling */
+	ce = engine->kernel_context;
+	if (ce) {
+		GEM_BUG_ON(test_bit(CONTEXT_VALID_BIT, &ce->flags));
+
+		/* First poison the image to verify we never fully trust it */
+		if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) && ce->state) {
+			struct drm_i915_gem_object *obj = ce->state->obj;
+			int type = i915_coherent_map_type(engine->i915);
+
+			map = i915_gem_object_pin_map(obj, type);
+			if (!IS_ERR(map)) {
+				memset(map, CONTEXT_REDZONE, obj->base.size);
+				i915_gem_object_flush_map(obj);
+				i915_gem_object_unpin_map(obj);
+			}
+		}
+
+		ce->ops->reset(ce);
+	}
+
 	if (engine->unpark)
 		engine->unpark(engine);
 
@@ -123,16 +145,16 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
 	unsigned long flags;
 	bool result = true;
 
+	/* GPU is pointing to the void, as good as in the kernel context. */
+	if (intel_gt_is_wedged(engine->gt))
+		return true;
+
 	GEM_BUG_ON(!intel_context_is_barrier(ce));
 
 	/* Already inside the kernel context, safe to power down. */
 	if (engine->wakeref_serial == engine->serial)
 		return true;
 
-	/* GPU is pointing to the void, as good as in the kernel context. */
-	if (intel_gt_is_wedged(engine->gt))
-		return true;
-
 	/*
 	 * Note, we do this without taking the timeline->mutex. We cannot
 	 * as we may be called while retiring the kernel context and so