1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2019 Intel Corporation
4  */
5 
6 #include "gem/i915_gem_context.h"
7 #include "gem/i915_gem_pm.h"
8 
9 #include "i915_drv.h"
10 #include "i915_trace.h"
11 
12 #include "intel_context.h"
13 #include "intel_engine.h"
14 #include "intel_engine_pm.h"
15 #include "intel_ring.h"
16 
17 static struct kmem_cache *slab_ce;
18 
19 static struct intel_context *intel_context_alloc(void)
20 {
21 	return kmem_cache_zalloc(slab_ce, GFP_KERNEL);
22 }
23 
24 static void rcu_context_free(struct rcu_head *rcu)
25 {
26 	struct intel_context *ce = container_of(rcu, typeof(*ce), rcu);
27 
28 	trace_intel_context_free(ce);
29 	kmem_cache_free(slab_ce, ce);
30 }
31 
32 void intel_context_free(struct intel_context *ce)
33 {
34 	call_rcu(&ce->rcu, rcu_context_free);
35 }
36 
37 struct intel_context *
38 intel_context_create(struct intel_engine_cs *engine)
39 {
40 	struct intel_context *ce;
41 
42 	ce = intel_context_alloc();
43 	if (!ce)
44 		return ERR_PTR(-ENOMEM);
45 
46 	intel_context_init(ce, engine);
47 	trace_intel_context_create(ce);
48 	return ce;
49 }
50 
51 int intel_context_alloc_state(struct intel_context *ce)
52 {
53 	int err = 0;
54 
55 	if (mutex_lock_interruptible(&ce->pin_mutex))
56 		return -EINTR;
57 
58 	if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
59 		if (intel_context_is_banned(ce)) {
60 			err = -EIO;
61 			goto unlock;
62 		}
63 
64 		err = ce->ops->alloc(ce);
65 		if (unlikely(err))
66 			goto unlock;
67 
68 		set_bit(CONTEXT_ALLOC_BIT, &ce->flags);
69 	}
70 
71 unlock:
72 	mutex_unlock(&ce->pin_mutex);
73 	return err;
74 }
75 
76 static int intel_context_active_acquire(struct intel_context *ce)
77 {
78 	int err;
79 
80 	__i915_active_acquire(&ce->active);
81 
82 	if (intel_context_is_barrier(ce) || intel_engine_uses_guc(ce->engine))
83 		return 0;
84 
85 	/* Preallocate tracking nodes */
86 	err = i915_active_acquire_preallocate_barrier(&ce->active,
87 						      ce->engine);
88 	if (err)
89 		i915_active_release(&ce->active);
90 
91 	return err;
92 }
93 
94 static void intel_context_active_release(struct intel_context *ce)
95 {
96 	/* Nodes preallocated in intel_context_active() */
97 	i915_active_acquire_barrier(&ce->active);
98 	i915_active_release(&ce->active);
99 }
100 
101 static int __context_pin_state(struct i915_vma *vma, struct i915_gem_ww_ctx *ww)
102 {
103 	unsigned int bias = i915_ggtt_pin_bias(vma) | PIN_OFFSET_BIAS;
104 	int err;
105 
106 	err = i915_ggtt_pin(vma, ww, 0, bias | PIN_HIGH);
107 	if (err)
108 		return err;
109 
110 	err = i915_active_acquire(&vma->active);
111 	if (err)
112 		goto err_unpin;
113 
114 	/*
115 	 * And mark it as a globally pinned object to let the shrinker know
116 	 * it cannot reclaim the object until we release it.
117 	 */
118 	i915_vma_make_unshrinkable(vma);
119 	vma->obj->mm.dirty = true;
120 
121 	return 0;
122 
123 err_unpin:
124 	i915_vma_unpin(vma);
125 	return err;
126 }
127 
128 static void __context_unpin_state(struct i915_vma *vma)
129 {
130 	i915_vma_make_shrinkable(vma);
131 	i915_active_release(&vma->active);
132 	__i915_vma_unpin(vma);
133 }
134 
135 static int __ring_active(struct intel_ring *ring,
136 			 struct i915_gem_ww_ctx *ww)
137 {
138 	int err;
139 
140 	err = intel_ring_pin(ring, ww);
141 	if (err)
142 		return err;
143 
144 	err = i915_active_acquire(&ring->vma->active);
145 	if (err)
146 		goto err_pin;
147 
148 	return 0;
149 
150 err_pin:
151 	intel_ring_unpin(ring);
152 	return err;
153 }
154 
155 static void __ring_retire(struct intel_ring *ring)
156 {
157 	i915_active_release(&ring->vma->active);
158 	intel_ring_unpin(ring);
159 }
160 
161 static int intel_context_pre_pin(struct intel_context *ce,
162 				 struct i915_gem_ww_ctx *ww)
163 {
164 	int err;
165 
166 	CE_TRACE(ce, "active\n");
167 
168 	err = __ring_active(ce->ring, ww);
169 	if (err)
170 		return err;
171 
172 	err = intel_timeline_pin(ce->timeline, ww);
173 	if (err)
174 		goto err_ring;
175 
176 	if (!ce->state)
177 		return 0;
178 
179 	err = __context_pin_state(ce->state, ww);
180 	if (err)
181 		goto err_timeline;
182 
183 
184 	return 0;
185 
186 err_timeline:
187 	intel_timeline_unpin(ce->timeline);
188 err_ring:
189 	__ring_retire(ce->ring);
190 	return err;
191 }
192 
193 static void intel_context_post_unpin(struct intel_context *ce)
194 {
195 	if (ce->state)
196 		__context_unpin_state(ce->state);
197 
198 	intel_timeline_unpin(ce->timeline);
199 	__ring_retire(ce->ring);
200 }
201 
202 int __intel_context_do_pin_ww(struct intel_context *ce,
203 			      struct i915_gem_ww_ctx *ww)
204 {
205 	bool handoff = false;
206 	void *vaddr;
207 	int err = 0;
208 
209 	if (unlikely(!test_bit(CONTEXT_ALLOC_BIT, &ce->flags))) {
210 		err = intel_context_alloc_state(ce);
211 		if (err)
212 			return err;
213 	}
214 
215 	/*
216 	 * We always pin the context/ring/timeline here, to ensure a pin
217 	 * refcount for __intel_context_active(), which prevent a lock
218 	 * inversion of ce->pin_mutex vs dma_resv_lock().
219 	 */
220 
221 	err = i915_gem_object_lock(ce->timeline->hwsp_ggtt->obj, ww);
222 	if (!err && ce->ring->vma->obj)
223 		err = i915_gem_object_lock(ce->ring->vma->obj, ww);
224 	if (!err && ce->state)
225 		err = i915_gem_object_lock(ce->state->obj, ww);
226 	if (!err)
227 		err = intel_context_pre_pin(ce, ww);
228 	if (err)
229 		return err;
230 
231 	err = i915_active_acquire(&ce->active);
232 	if (err)
233 		goto err_ctx_unpin;
234 
235 	err = ce->ops->pre_pin(ce, ww, &vaddr);
236 	if (err)
237 		goto err_release;
238 
239 	err = mutex_lock_interruptible(&ce->pin_mutex);
240 	if (err)
241 		goto err_post_unpin;
242 
243 	if (unlikely(intel_context_is_closed(ce))) {
244 		err = -ENOENT;
245 		goto err_unlock;
246 	}
247 
248 	if (likely(!atomic_add_unless(&ce->pin_count, 1, 0))) {
249 		err = intel_context_active_acquire(ce);
250 		if (unlikely(err))
251 			goto err_unlock;
252 
253 		err = ce->ops->pin(ce, vaddr);
254 		if (err) {
255 			intel_context_active_release(ce);
256 			goto err_unlock;
257 		}
258 
259 		CE_TRACE(ce, "pin ring:{start:%08x, head:%04x, tail:%04x}\n",
260 			 i915_ggtt_offset(ce->ring->vma),
261 			 ce->ring->head, ce->ring->tail);
262 
263 		handoff = true;
264 		smp_mb__before_atomic(); /* flush pin before it is visible */
265 		atomic_inc(&ce->pin_count);
266 	}
267 
268 	GEM_BUG_ON(!intel_context_is_pinned(ce)); /* no overflow! */
269 
270 	trace_intel_context_do_pin(ce);
271 
272 err_unlock:
273 	mutex_unlock(&ce->pin_mutex);
274 err_post_unpin:
275 	if (!handoff)
276 		ce->ops->post_unpin(ce);
277 err_release:
278 	i915_active_release(&ce->active);
279 err_ctx_unpin:
280 	intel_context_post_unpin(ce);
281 
282 	/*
283 	 * Unlock the hwsp_ggtt object since it's shared.
284 	 * In principle we can unlock all the global state locked above
285 	 * since it's pinned and doesn't need fencing, and will
286 	 * thus remain resident until it is explicitly unpinned.
287 	 */
288 	i915_gem_ww_unlock_single(ce->timeline->hwsp_ggtt->obj);
289 
290 	return err;
291 }
292 
293 int __intel_context_do_pin(struct intel_context *ce)
294 {
295 	struct i915_gem_ww_ctx ww;
296 	int err;
297 
298 	i915_gem_ww_ctx_init(&ww, true);
299 retry:
300 	err = __intel_context_do_pin_ww(ce, &ww);
301 	if (err == -EDEADLK) {
302 		err = i915_gem_ww_ctx_backoff(&ww);
303 		if (!err)
304 			goto retry;
305 	}
306 	i915_gem_ww_ctx_fini(&ww);
307 	return err;
308 }
309 
310 void __intel_context_do_unpin(struct intel_context *ce, int sub)
311 {
312 	if (!atomic_sub_and_test(sub, &ce->pin_count))
313 		return;
314 
315 	CE_TRACE(ce, "unpin\n");
316 	ce->ops->unpin(ce);
317 	ce->ops->post_unpin(ce);
318 
319 	/*
320 	 * Once released, we may asynchronously drop the active reference.
321 	 * As that may be the only reference keeping the context alive,
322 	 * take an extra now so that it is not freed before we finish
323 	 * dereferencing it.
324 	 */
325 	intel_context_get(ce);
326 	intel_context_active_release(ce);
327 	trace_intel_context_do_unpin(ce);
328 	intel_context_put(ce);
329 }
330 
331 static void __intel_context_retire(struct i915_active *active)
332 {
333 	struct intel_context *ce = container_of(active, typeof(*ce), active);
334 
335 	CE_TRACE(ce, "retire runtime: { total:%lluns, avg:%lluns }\n",
336 		 intel_context_get_total_runtime_ns(ce),
337 		 intel_context_get_avg_runtime_ns(ce));
338 
339 	set_bit(CONTEXT_VALID_BIT, &ce->flags);
340 	intel_context_post_unpin(ce);
341 	intel_context_put(ce);
342 }
343 
344 static int __intel_context_active(struct i915_active *active)
345 {
346 	struct intel_context *ce = container_of(active, typeof(*ce), active);
347 
348 	intel_context_get(ce);
349 
350 	/* everything should already be activated by intel_context_pre_pin() */
351 	GEM_WARN_ON(!i915_active_acquire_if_busy(&ce->ring->vma->active));
352 	__intel_ring_pin(ce->ring);
353 
354 	__intel_timeline_pin(ce->timeline);
355 
356 	if (ce->state) {
357 		GEM_WARN_ON(!i915_active_acquire_if_busy(&ce->state->active));
358 		__i915_vma_pin(ce->state);
359 		i915_vma_make_unshrinkable(ce->state);
360 	}
361 
362 	return 0;
363 }
364 
365 static int __i915_sw_fence_call
366 sw_fence_dummy_notify(struct i915_sw_fence *sf,
367 		      enum i915_sw_fence_notify state)
368 {
369 	return NOTIFY_DONE;
370 }
371 
372 void
373 intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
374 {
375 	GEM_BUG_ON(!engine->cops);
376 	GEM_BUG_ON(!engine->gt->vm);
377 
378 	kref_init(&ce->ref);
379 
380 	ce->engine = engine;
381 	ce->ops = engine->cops;
382 	ce->sseu = engine->sseu;
383 	ce->ring = NULL;
384 	ce->ring_size = SZ_4K;
385 
386 	ewma_runtime_init(&ce->runtime.avg);
387 
388 	ce->vm = i915_vm_get(engine->gt->vm);
389 
390 	/* NB ce->signal_link/lock is used under RCU */
391 	spin_lock_init(&ce->signal_lock);
392 	INIT_LIST_HEAD(&ce->signals);
393 
394 	mutex_init(&ce->pin_mutex);
395 
396 	spin_lock_init(&ce->guc_state.lock);
397 	INIT_LIST_HEAD(&ce->guc_state.fences);
398 
399 	spin_lock_init(&ce->guc_active.lock);
400 	INIT_LIST_HEAD(&ce->guc_active.requests);
401 
402 	ce->guc_id = GUC_INVALID_LRC_ID;
403 	INIT_LIST_HEAD(&ce->guc_id_link);
404 
405 	/*
406 	 * Initialize fence to be complete as this is expected to be complete
407 	 * unless there is a pending schedule disable outstanding.
408 	 */
409 	i915_sw_fence_init(&ce->guc_blocked, sw_fence_dummy_notify);
410 	i915_sw_fence_commit(&ce->guc_blocked);
411 
412 	i915_active_init(&ce->active,
413 			 __intel_context_active, __intel_context_retire, 0);
414 }
415 
416 void intel_context_fini(struct intel_context *ce)
417 {
418 	if (ce->timeline)
419 		intel_timeline_put(ce->timeline);
420 	i915_vm_put(ce->vm);
421 
422 	mutex_destroy(&ce->pin_mutex);
423 	i915_active_fini(&ce->active);
424 }
425 
426 void i915_context_module_exit(void)
427 {
428 	kmem_cache_destroy(slab_ce);
429 }
430 
431 int __init i915_context_module_init(void)
432 {
433 	slab_ce = KMEM_CACHE(intel_context, SLAB_HWCACHE_ALIGN);
434 	if (!slab_ce)
435 		return -ENOMEM;
436 
437 	return 0;
438 }
439 
440 void intel_context_enter_engine(struct intel_context *ce)
441 {
442 	intel_engine_pm_get(ce->engine);
443 	intel_timeline_enter(ce->timeline);
444 }
445 
446 void intel_context_exit_engine(struct intel_context *ce)
447 {
448 	intel_timeline_exit(ce->timeline);
449 	intel_engine_pm_put(ce->engine);
450 }
451 
452 int intel_context_prepare_remote_request(struct intel_context *ce,
453 					 struct i915_request *rq)
454 {
455 	struct intel_timeline *tl = ce->timeline;
456 	int err;
457 
458 	/* Only suitable for use in remotely modifying this context */
459 	GEM_BUG_ON(rq->context == ce);
460 
461 	if (rcu_access_pointer(rq->timeline) != tl) { /* timeline sharing! */
462 		/* Queue this switch after current activity by this context. */
463 		err = i915_active_fence_set(&tl->last_request, rq);
464 		if (err)
465 			return err;
466 	}
467 
468 	/*
469 	 * Guarantee context image and the timeline remains pinned until the
470 	 * modifying request is retired by setting the ce activity tracker.
471 	 *
472 	 * But we only need to take one pin on the account of it. Or in other
473 	 * words transfer the pinned ce object to tracked active request.
474 	 */
475 	GEM_BUG_ON(i915_active_is_idle(&ce->active));
476 	return i915_active_add_request(&ce->active, rq);
477 }
478 
479 struct i915_request *intel_context_create_request(struct intel_context *ce)
480 {
481 	struct i915_gem_ww_ctx ww;
482 	struct i915_request *rq;
483 	int err;
484 
485 	i915_gem_ww_ctx_init(&ww, true);
486 retry:
487 	err = intel_context_pin_ww(ce, &ww);
488 	if (!err) {
489 		rq = i915_request_create(ce);
490 		intel_context_unpin(ce);
491 	} else if (err == -EDEADLK) {
492 		err = i915_gem_ww_ctx_backoff(&ww);
493 		if (!err)
494 			goto retry;
495 		rq = ERR_PTR(err);
496 	} else {
497 		rq = ERR_PTR(err);
498 	}
499 
500 	i915_gem_ww_ctx_fini(&ww);
501 
502 	if (IS_ERR(rq))
503 		return rq;
504 
505 	/*
506 	 * timeline->mutex should be the inner lock, but is used as outer lock.
507 	 * Hack around this to shut up lockdep in selftests..
508 	 */
509 	lockdep_unpin_lock(&ce->timeline->mutex, rq->cookie);
510 	mutex_release(&ce->timeline->mutex.dep_map, _RET_IP_);
511 	mutex_acquire(&ce->timeline->mutex.dep_map, SINGLE_DEPTH_NESTING, 0, _RET_IP_);
512 	rq->cookie = lockdep_pin_lock(&ce->timeline->mutex);
513 
514 	return rq;
515 }
516 
517 struct i915_request *intel_context_find_active_request(struct intel_context *ce)
518 {
519 	struct i915_request *rq, *active = NULL;
520 	unsigned long flags;
521 
522 	GEM_BUG_ON(!intel_engine_uses_guc(ce->engine));
523 
524 	spin_lock_irqsave(&ce->guc_active.lock, flags);
525 	list_for_each_entry_reverse(rq, &ce->guc_active.requests,
526 				    sched.link) {
527 		if (i915_request_completed(rq))
528 			break;
529 
530 		active = rq;
531 	}
532 	spin_unlock_irqrestore(&ce->guc_active.lock, flags);
533 
534 	return active;
535 }
536 
537 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
538 #include "selftest_context.c"
539 #endif
540