drm/i915/guc: Implement multi-lrc reset

Update context and full GPU reset to work with multi-lrc. The idea is
parent context tracks all the active requests inflight for itself and
its children. The parent context owns the reset replaying / canceling
requests as needed.

v2:
 (John Harrison)
  - Simply loop in find active request
  - Add comments to find ative request / reset loop
v3:
 (John Harrison)
  - s/its'/its/g
  - Fix comment when searching for active request
  - Reorder if state in __guc_reset_context
v4:
 (Kernel test robot)
  - Delete unused is_multi_lrc function
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-15-matthew.brost@intel.com

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

@@ -528,20 +528,29 @@ struct i915_request *intel_context_create_request(struct intel_context *ce)
 
 struct i915_request *intel_context_find_active_request(struct intel_context *ce)
 {
+	struct intel_context *parent = intel_context_to_parent(ce);
 	struct i915_request *rq, *active = NULL;
 	unsigned long flags;
 
 	GEM_BUG_ON(!intel_engine_uses_guc(ce->engine));
 
-	spin_lock_irqsave(&ce->guc_state.lock, flags);
-	list_for_each_entry_reverse(rq, &ce->guc_state.requests,
+	/*
+	 * We search the parent list to find an active request on the submitted
+	 * context. The parent list contains the requests for all the contexts
+	 * in the relationship so we have to do a compare of each request's
+	 * context.
+	 */
+	spin_lock_irqsave(&parent->guc_state.lock, flags);
+	list_for_each_entry_reverse(rq, &parent->guc_state.requests,
 				    sched.link) {
+		if (rq->context != ce)
+			continue;
 		if (i915_request_completed(rq))
 			break;
 
 		active = rq;
 	}
-	spin_unlock_irqrestore(&ce->guc_state.lock, flags);
+	spin_unlock_irqrestore(&parent->guc_state.lock, flags);
 
 	return active;
 }

drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c

@@ -1217,10 +1217,15 @@ __unwind_incomplete_requests(struct intel_context *ce)
 
 static void __guc_reset_context(struct intel_context *ce, bool stalled)
 {
+	bool local_stalled;
 	struct i915_request *rq;
 	unsigned long flags;
 	u32 head;
+	int i, number_children = ce->parallel.number_children;
 	bool skip = false;
+	struct intel_context *parent = ce;
+
+	GEM_BUG_ON(intel_context_is_child(ce));
 
 	intel_context_get(ce);
 
@@ -1246,25 +1251,38 @@ static void __guc_reset_context(struct intel_context *ce, bool stalled)
 	if (unlikely(skip))
 		goto out_put;
 
+	/*
+	 * For each context in the relationship find the hanging request
+	 * resetting each context / request as needed
+	 */
+	for (i = 0; i < number_children + 1; ++i) {
+		if (!intel_context_is_pinned(ce))
+			goto next_context;
+
+		local_stalled = false;
 		rq = intel_context_find_active_request(ce);
 		if (!rq) {
 			head = ce->ring->tail;
-		stalled = false;
 			goto out_replay;
 		}
 
-	if (!i915_request_started(rq))
-		stalled = false;
+		if (i915_request_started(rq))
+			local_stalled = true;
 
 		GEM_BUG_ON(i915_active_is_idle(&ce->active));
 		head = intel_ring_wrap(ce->ring, rq->head);
-	__i915_request_reset(rq, stalled);
 
+		__i915_request_reset(rq, local_stalled && stalled);
 out_replay:
-	guc_reset_state(ce, head, stalled);
-	__unwind_incomplete_requests(ce);
+		guc_reset_state(ce, head, local_stalled && stalled);
+next_context:
+		if (i != number_children)
+			ce = list_next_entry(ce, parallel.child_link);
+	}
+
+	__unwind_incomplete_requests(parent);
 out_put:
-	intel_context_put(ce);
+	intel_context_put(parent);
 }
 
 void intel_guc_submission_reset(struct intel_guc *guc, bool stalled)
@@ -1285,7 +1303,8 @@ void intel_guc_submission_reset(struct intel_guc *guc, bool stalled)
 
 		xa_unlock(&guc->context_lookup);
 
-		if (intel_context_is_pinned(ce))
+		if (intel_context_is_pinned(ce) &&
+		    !intel_context_is_child(ce))
 			__guc_reset_context(ce, stalled);
 
 		intel_context_put(ce);
@@ -1377,7 +1396,8 @@ void intel_guc_submission_cancel_requests(struct intel_guc *guc)
 
 		xa_unlock(&guc->context_lookup);
 
-		if (intel_context_is_pinned(ce))
+		if (intel_context_is_pinned(ce) &&
+		    !intel_context_is_child(ce))
 			guc_cancel_context_requests(ce);
 
 		intel_context_put(ce);
@@ -2070,6 +2090,8 @@ static struct i915_sw_fence *guc_context_block(struct intel_context *ce)
 	u16 guc_id;
 	bool enabled;
 
+	GEM_BUG_ON(intel_context_is_child(ce));
+
 	spin_lock_irqsave(&ce->guc_state.lock, flags);
 
 	incr_context_blocked(ce);
@@ -2124,6 +2146,7 @@ static void guc_context_unblock(struct intel_context *ce)
 	bool enable;
 
 	GEM_BUG_ON(context_enabled(ce));
+	GEM_BUG_ON(intel_context_is_child(ce));
 
 	spin_lock_irqsave(&ce->guc_state.lock, flags);
 
@@ -2150,11 +2173,14 @@ static void guc_context_unblock(struct intel_context *ce)
 static void guc_context_cancel_request(struct intel_context *ce,
 				       struct i915_request *rq)
 {
+	struct intel_context *block_context =
+		request_to_scheduling_context(rq);
+
 	if (i915_sw_fence_signaled(&rq->submit)) {
 		struct i915_sw_fence *fence;
 
 		intel_context_get(ce);
-		fence = guc_context_block(ce);
+		fence = guc_context_block(block_context);
 		i915_sw_fence_wait(fence);
 		if (!i915_request_completed(rq)) {
 			__i915_request_skip(rq);
@@ -2168,7 +2194,7 @@ static void guc_context_cancel_request(struct intel_context *ce,
 		 */
 		flush_work(&ce_to_guc(ce)->ct.requests.worker);
 
-		guc_context_unblock(ce);
+		guc_context_unblock(block_context);
 		intel_context_put(ce);
 	}
 }
@@ -2194,6 +2220,8 @@ static void guc_context_ban(struct intel_context *ce, struct i915_request *rq)
 	intel_wakeref_t wakeref;
 	unsigned long flags;
 
+	GEM_BUG_ON(intel_context_is_child(ce));
+
 	guc_flush_submissions(guc);
 
 	spin_lock_irqsave(&ce->guc_state.lock, flags);