drm/i915/guc: Handle context reset notification

GuC will issue a reset on detecting an engine hang and will notify
the driver via a G2H message. The driver will service the notification
by resetting the guilty context to a simple state or banning it
completely.

v2:
 (John Harrison)
  - Move msg[0] lookup after length check
v3:
 (John Harrison)
  - s/drm_dbg/drm_err

Cc: Matthew Brost <matthew.brost@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727002348.97202-13-matthew.brost@intel.com

drivers/gpu/drm/i915/gt/uc/intel_guc.h

@@ -269,6 +269,8 @@ int intel_guc_deregister_done_process_msg(struct intel_guc *guc,
 					  const u32 *msg, u32 len);
 int intel_guc_sched_done_process_msg(struct intel_guc *guc,
 				     const u32 *msg, u32 len);
+int intel_guc_context_reset_process_msg(struct intel_guc *guc,
+					const u32 *msg, u32 len);
 
 void intel_guc_submission_reset_prepare(struct intel_guc *guc);
 void intel_guc_submission_reset(struct intel_guc *guc, bool stalled);

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

@@ -984,6 +984,9 @@ static int ct_process_request(struct intel_guc_ct *ct, struct ct_incoming_msg *r
 	case INTEL_GUC_ACTION_SCHED_CONTEXT_MODE_DONE:
 		ret = intel_guc_sched_done_process_msg(guc, payload, len);
 		break;
+	case INTEL_GUC_ACTION_CONTEXT_RESET_NOTIFICATION:
+		ret = intel_guc_context_reset_process_msg(guc, payload, len);
+		break;
 	default:
 		ret = -EOPNOTSUPP;
 		break;

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

@@ -2201,6 +2201,42 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
 	return 0;
 }
 
+static void guc_context_replay(struct intel_context *ce)
+{
+	struct i915_sched_engine *sched_engine = ce->engine->sched_engine;
+
+	__guc_reset_context(ce, true);
+	tasklet_hi_schedule(&sched_engine->tasklet);
+}
+
+static void guc_handle_context_reset(struct intel_guc *guc,
+				     struct intel_context *ce)
+{
+	trace_intel_context_reset(ce);
+	guc_context_replay(ce);
+}
+
+int intel_guc_context_reset_process_msg(struct intel_guc *guc,
+					const u32 *msg, u32 len)
+{
+	struct intel_context *ce;
+	int desc_idx;
+
+	if (unlikely(len != 1)) {
+		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
+		return -EPROTO;
+	}
+
+	desc_idx = msg[0];
+	ce = g2h_context_lookup(guc, desc_idx);
+	if (unlikely(!ce))
+		return -EPROTO;
+
+	guc_handle_context_reset(guc, ce);
+
+	return 0;
+}
+
 void intel_guc_submission_print_info(struct intel_guc *guc,
 				     struct drm_printer *p)
 {

drivers/gpu/drm/i915/i915_trace.h

@@ -920,6 +920,11 @@ DECLARE_EVENT_CLASS(intel_context,
 			      __entry->guc_sched_state_no_lock)
 );
 
+DEFINE_EVENT(intel_context, intel_context_reset,
+	     TP_PROTO(struct intel_context *ce),
+	     TP_ARGS(ce)
+);
+
 DEFINE_EVENT(intel_context, intel_context_register,
 	     TP_PROTO(struct intel_context *ce),
 	     TP_ARGS(ce)
@@ -1007,6 +1012,11 @@ trace_i915_request_out(struct i915_request *rq)
 {
 }
 
+static inline void
+trace_intel_context_reset(struct intel_context *ce)
+{
+}
+
 static inline void
 trace_intel_context_register(struct intel_context *ce)
 {