5 files changed, 187 insertions, 50 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 2dfaddb8811e..7c369737d1cf 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1760,7 +1760,8 @@ static void defer_active(struct intel_engine_cs *engine)
 
 static bool
 need_timeslice(const struct intel_engine_cs *engine,
-	       const struct i915_request *rq)
+	       const struct i915_request *rq,
+	       const struct rb_node *rb)
 {
 	int hint;
 
@@ -1768,9 +1769,28 @@ need_timeslice(const struct intel_engine_cs *engine,
 		return false;
 
 	hint = engine->execlists.queue_priority_hint;
+
+	if (rb) {
+		const struct virtual_engine *ve =
+			rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
+		const struct intel_engine_cs *inflight =
+			intel_context_inflight(&ve->context);
+
+		if (!inflight || inflight == engine) {
+			struct i915_request *next;
+
+			rcu_read_lock();
+			next = READ_ONCE(ve->request);
+			if (next)
+				hint = max(hint, rq_prio(next));
+			rcu_read_unlock();
+		}
+	}
+
 	if (!list_is_last(&rq->sched.link, &engine->active.requests))
 		hint = max(hint, rq_prio(list_next_entry(rq, sched.link)));
 
+	GEM_BUG_ON(hint >= I915_PRIORITY_UNPREEMPTABLE);
 	return hint >= effective_prio(rq);
 }
 
@@ -1837,10 +1857,9 @@ static void set_timeslice(struct intel_engine_cs *engine)
 	set_timer_ms(&engine->execlists.timer, active_timeslice(engine));
 }
 
-static void start_timeslice(struct intel_engine_cs *engine)
+static void start_timeslice(struct intel_engine_cs *engine, int prio)
 {
 	struct intel_engine_execlists *execlists = &engine->execlists;
-	int prio = queue_prio(execlists);
 
 	WRITE_ONCE(execlists->switch_priority_hint, prio);
 	if (prio == INT_MIN)
@@ -1976,7 +1995,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 			__unwind_incomplete_requests(engine);
 
 			last = NULL;
-		} else if (need_timeslice(engine, last) &&
+		} else if (need_timeslice(engine, last, rb) &&
 			   timeslice_expired(execlists, last)) {
 			ENGINE_TRACE(engine,
 				     "expired last=%llx:%lld, prio=%d, hint=%d, yield?=%s\n",
@@ -2019,7 +2038,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 				 * Even if ELSP[1] is occupied and not worthy
 				 * of timeslices, our queue might be.
 				 */
-				start_timeslice(engine);
+				start_timeslice(engine, queue_prio(execlists));
 				return;
 			}
 		}
@@ -2054,7 +2073,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 
 			if (last && !can_merge_rq(last, rq)) {
 				spin_unlock(&ve->base.active.lock);
-				start_timeslice(engine);
+				start_timeslice(engine, rq_prio(rq));
 				return; /* leave this for another sibling */
 			}
 
diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index f95ae15ce865..904193960584 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -811,7 +811,7 @@ slice_semaphore_queue(struct intel_engine_cs *outer,
 		}
 	}
 
-	err = release_queue(outer, vma, n, INT_MAX);
+	err = release_queue(outer, vma, n, I915_PRIORITY_BARRIER);
 	if (err)
 		goto out;
 
@@ -1276,6 +1276,121 @@ err_obj:
 	return err;
 }
 
+static int live_timeslice_nopreempt(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	struct igt_spinner spin;
+	int err = 0;
+
+	/*
+	 * We should not timeslice into a request that is marked with
+	 * I915_REQUEST_NOPREEMPT.
+	 */
+	if (!IS_ACTIVE(CONFIG_DRM_I915_TIMESLICE_DURATION))
+		return 0;
+
+	if (igt_spinner_init(&spin, gt))
+		return -ENOMEM;
+
+	for_each_engine(engine, gt, id) {
+		struct intel_context *ce;
+		struct i915_request *rq;
+		unsigned long timeslice;
+
+		if (!intel_engine_has_preemption(engine))
+			continue;
+
+		ce = intel_context_create(engine);
+		if (IS_ERR(ce)) {
+			err = PTR_ERR(ce);
+			break;
+		}
+
+		engine_heartbeat_disable(engine);
+		timeslice = xchg(&engine->props.timeslice_duration_ms, 1);
+
+		/* Create an unpreemptible spinner */
+
+		rq = igt_spinner_create_request(&spin, ce, MI_ARB_CHECK);
+		intel_context_put(ce);
+		if (IS_ERR(rq)) {
+			err = PTR_ERR(rq);
+			goto out_heartbeat;
+		}
+
+		i915_request_get(rq);
+		i915_request_add(rq);
+
+		if (!igt_wait_for_spinner(&spin, rq)) {
+			i915_request_put(rq);
+			err = -ETIME;
+			goto out_spin;
+		}
+
+		set_bit(I915_FENCE_FLAG_NOPREEMPT, &rq->fence.flags);
+		i915_request_put(rq);
+
+		/* Followed by a maximum priority barrier (heartbeat) */
+
+		ce = intel_context_create(engine);
+		if (IS_ERR(ce)) {
+			err = PTR_ERR(rq);
+			goto out_spin;
+		}
+
+		rq = intel_context_create_request(ce);
+		intel_context_put(ce);
+		if (IS_ERR(rq)) {
+			err = PTR_ERR(rq);
+			goto out_spin;
+		}
+
+		rq->sched.attr.priority = I915_PRIORITY_BARRIER;
+		i915_request_get(rq);
+		i915_request_add(rq);
+
+		/*
+		 * Wait until the barrier is in ELSP, and we know timeslicing
+		 * will have been activated.
+		 */
+		if (wait_for_submit(engine, rq, HZ / 2)) {
+			i915_request_put(rq);
+			err = -ETIME;
+			goto out_spin;
+		}
+
+		/*
+		 * Since the ELSP[0] request is unpreemptible, it should not
+		 * allow the maximum priority barrier through. Wait long
+		 * enough to see if it is timesliced in by mistake.
+		 */
+		if (i915_request_wait(rq, 0, timeslice_threshold(engine)) >= 0) {
+			pr_err("%s: I915_PRIORITY_BARRIER request completed, bypassing no-preempt request\n",
+			       engine->name);
+			err = -EINVAL;
+		}
+		i915_request_put(rq);
+
+out_spin:
+		igt_spinner_end(&spin);
+out_heartbeat:
+		xchg(&engine->props.timeslice_duration_ms, timeslice);
+		engine_heartbeat_enable(engine);
+		if (err)
+			break;
+
+		if (igt_flush_test(gt->i915)) {
+			err = -EIO;
+			break;
+		}
+	}
+
+	igt_spinner_fini(&spin);
+	return err;
+}
+
 static int live_busywait_preempt(void *arg)
 {
 	struct intel_gt *gt = arg;
@@ -3962,6 +4077,7 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915)
 		SUBTEST(live_timeslice_preempt),
 		SUBTEST(live_timeslice_rewind),
 		SUBTEST(live_timeslice_queue),
+		SUBTEST(live_timeslice_nopreempt),
 		SUBTEST(live_busywait_preempt),
 		SUBTEST(live_preempt),
 		SUBTEST(live_late_preempt),
diff --git a/drivers/gpu/drm/i915/gt/selftest_workarounds.c b/drivers/gpu/drm/i915/gt/selftest_workarounds.c
index 5ed323254ee1..32785463ec9e 100644
--- a/drivers/gpu/drm/i915/gt/selftest_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/selftest_workarounds.c
@@ -623,6 +623,8 @@ err_request:
 				err = -EINVAL;
 				goto out_unpin;
 			}
+		} else {
+			rsvd = 0;
 		}
 
 		expect = results[0];
diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 2c062534eac1..569a87d0d799 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -269,12 +269,48 @@ static bool exclusive_mmio_access(const struct drm_i915_private *i915)
 	return IS_GEN(i915, 7);
 }
 
+static void engine_sample(struct intel_engine_cs *engine, unsigned int period_ns)
+{
+	struct intel_engine_pmu *pmu = &engine->pmu;
+	bool busy;
+	u32 val;
+
+	val = ENGINE_READ_FW(engine, RING_CTL);
+	if (val == 0) /* powerwell off => engine idle */
+		return;
+
+	if (val & RING_WAIT)
+		add_sample(&pmu->sample[I915_SAMPLE_WAIT], period_ns);
+	if (val & RING_WAIT_SEMAPHORE)
+		add_sample(&pmu->sample[I915_SAMPLE_SEMA], period_ns);
+
+	/* No need to sample when busy stats are supported. */
+	if (intel_engine_supports_stats(engine))
+		return;
+
+	/*
+	 * While waiting on a semaphore or event, MI_MODE reports the
+	 * ring as idle. However, previously using the seqno, and with
+	 * execlists sampling, we account for the ring waiting as the
+	 * engine being busy. Therefore, we record the sample as being
+	 * busy if either waiting or !idle.
+	 */
+	busy = val & (RING_WAIT_SEMAPHORE | RING_WAIT);
+	if (!busy) {
+		val = ENGINE_READ_FW(engine, RING_MI_MODE);
+		busy = !(val & MODE_IDLE);
+	}
+	if (busy)
+		add_sample(&pmu->sample[I915_SAMPLE_BUSY], period_ns);
+}
+
 static void
 engines_sample(struct intel_gt *gt, unsigned int period_ns)
 {
 	struct drm_i915_private *i915 = gt->i915;
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
+	unsigned long flags;
 
 	if ((i915->pmu.enable & ENGINE_SAMPLE_MASK) == 0)
 		return;
@@ -283,53 +319,17 @@ engines_sample(struct intel_gt *gt, unsigned int period_ns)
 		return;
 
 	for_each_engine(engine, gt, id) {
-		struct intel_engine_pmu *pmu = &engine->pmu;
-		spinlock_t *mmio_lock;
-		unsigned long flags;
-		bool busy;
-		u32 val;
-
 		if (!intel_engine_pm_get_if_awake(engine))
 			continue;
 
-		mmio_lock = NULL;
-		if (exclusive_mmio_access(i915))
-			mmio_lock = &engine->uncore->lock;
-
-		if (unlikely(mmio_lock))
-			spin_lock_irqsave(mmio_lock, flags);
-
-		val = ENGINE_READ_FW(engine, RING_CTL);
-		if (val == 0) /* powerwell off => engine idle */
-			goto skip;
-
-		if (val & RING_WAIT)
-			add_sample(&pmu->sample[I915_SAMPLE_WAIT], period_ns);
-		if (val & RING_WAIT_SEMAPHORE)
-			add_sample(&pmu->sample[I915_SAMPLE_SEMA], period_ns);
-
-		/* No need to sample when busy stats are supported. */
-		if (intel_engine_supports_stats(engine))
-			goto skip;
-
-		/*
-		 * While waiting on a semaphore or event, MI_MODE reports the
-		 * ring as idle. However, previously using the seqno, and with
-		 * execlists sampling, we account for the ring waiting as the
-		 * engine being busy. Therefore, we record the sample as being
-		 * busy if either waiting or !idle.
-		 */
-		busy = val & (RING_WAIT_SEMAPHORE | RING_WAIT);
-		if (!busy) {
-			val = ENGINE_READ_FW(engine, RING_MI_MODE);
-			busy = !(val & MODE_IDLE);
+		if (exclusive_mmio_access(i915)) {
+			spin_lock_irqsave(&engine->uncore->lock, flags);
+			engine_sample(engine, period_ns);
+			spin_unlock_irqrestore(&engine->uncore->lock, flags);
+		} else {
+			engine_sample(engine, period_ns);
 		}
-		if (busy)
-			add_sample(&pmu->sample[I915_SAMPLE_BUSY], period_ns);
 
-skip:
-		if (unlikely(mmio_lock))
-			spin_unlock_irqrestore(mmio_lock, flags);
 		intel_engine_pm_put_async(engine);
 	}
 }
diff --git a/drivers/gpu/drm/i915/i915_priolist_types.h b/drivers/gpu/drm/i915/i915_priolist_types.h
index 732aad148881..eb97d626f9ad 100644
--- a/drivers/gpu/drm/i915/i915_priolist_types.h
+++ b/drivers/gpu/drm/i915/i915_priolist_types.h
@@ -45,7 +45,7 @@ enum {
  * active request.
  */
 #define I915_PRIORITY_UNPREEMPTABLE INT_MAX
-#define I915_PRIORITY_BARRIER INT_MAX
+#define I915_PRIORITY_BARRIER (I915_PRIORITY_UNPREEMPTABLE - 1)
 
 #define __NO_PREEMPTION (I915_PRIORITY_WAIT)