1 // SPDX-License-Identifier: MIT
3 * Copyright © 2014 Intel Corporation
7 * DOC: Logical Rings, Logical Ring Contexts and Execlists
10 * GEN8 brings an expansion of the HW contexts: "Logical Ring Contexts".
11 * These expanded contexts enable a number of new abilities, especially
12 * "Execlists" (also implemented in this file).
14 * One of the main differences with the legacy HW contexts is that logical
15 * ring contexts incorporate many more things to the context's state, like
16 * PDPs or ringbuffer control registers:
18 * The reason why PDPs are included in the context is straightforward: as
19 * PPGTTs (per-process GTTs) are actually per-context, having the PDPs
20 * contained there mean you don't need to do a ppgtt->switch_mm yourself,
21 * instead, the GPU will do it for you on the context switch.
23 * But, what about the ringbuffer control registers (head, tail, etc..)?
24 * shouldn't we just need a set of those per engine command streamer? This is
25 * where the name "Logical Rings" starts to make sense: by virtualizing the
26 * rings, the engine cs shifts to a new "ring buffer" with every context
27 * switch. When you want to submit a workload to the GPU you: A) choose your
28 * context, B) find its appropriate virtualized ring, C) write commands to it
29 * and then, finally, D) tell the GPU to switch to that context.
31 * Instead of the legacy MI_SET_CONTEXT, the way you tell the GPU to switch
32 * to a contexts is via a context execution list, ergo "Execlists".
35 * Regarding the creation of contexts, we have:
37 * - One global default context.
38 * - One local default context for each opened fd.
39 * - One local extra context for each context create ioctl call.
41 * Now that ringbuffers belong per-context (and not per-engine, like before)
42 * and that contexts are uniquely tied to a given engine (and not reusable,
43 * like before) we need:
45 * - One ringbuffer per-engine inside each context.
46 * - One backing object per-engine inside each context.
48 * The global default context starts its life with these new objects fully
49 * allocated and populated. The local default context for each opened fd is
50 * more complex, because we don't know at creation time which engine is going
51 * to use them. To handle this, we have implemented a deferred creation of LR
54 * The local context starts its life as a hollow or blank holder, that only
55 * gets populated for a given engine once we receive an execbuffer. If later
56 * on we receive another execbuffer ioctl for the same context but a different
57 * engine, we allocate/populate a new ringbuffer and context backing object and
60 * Finally, regarding local contexts created using the ioctl call: as they are
61 * only allowed with the render ring, we can allocate & populate them right
62 * away (no need to defer anything, at least for now).
64 * Execlists implementation:
65 * Execlists are the new method by which, on gen8+ hardware, workloads are
66 * submitted for execution (as opposed to the legacy, ringbuffer-based, method).
67 * This method works as follows:
69 * When a request is committed, its commands (the BB start and any leading or
70 * trailing commands, like the seqno breadcrumbs) are placed in the ringbuffer
71 * for the appropriate context. The tail pointer in the hardware context is not
72 * updated at this time, but instead, kept by the driver in the ringbuffer
73 * structure. A structure representing this request is added to a request queue
74 * for the appropriate engine: this structure contains a copy of the context's
75 * tail after the request was written to the ring buffer and a pointer to the
78 * If the engine's request queue was empty before the request was added, the
79 * queue is processed immediately. Otherwise the queue will be processed during
80 * a context switch interrupt. In any case, elements on the queue will get sent
81 * (in pairs) to the GPU's ExecLists Submit Port (ELSP, for short) with a
82 * globally unique 20-bits submission ID.
84 * When execution of a request completes, the GPU updates the context status
85 * buffer with a context complete event and generates a context switch interrupt.
86 * During the interrupt handling, the driver examines the events in the buffer:
87 * for each context complete event, if the announced ID matches that on the head
88 * of the request queue, then that request is retired and removed from the queue.
90 * After processing, if any requests were retired and the queue is not empty
91 * then a new execution list can be submitted. The two requests at the front of
92 * the queue are next to be submitted but since a context may not occur twice in
93 * an execution list, if subsequent requests have the same ID as the first then
94 * the two requests must be combined. This is done simply by discarding requests
95 * at the head of the queue until either only one requests is left (in which case
96 * we use a NULL second context) or the first two requests have unique IDs.
98 * By always executing the first two requests in the queue the driver ensures
99 * that the GPU is kept as busy as possible. In the case where a single context
100 * completes but a second context is still executing, the request for this second
101 * context will be at the head of the queue when we remove the first one. This
102 * request will then be resubmitted along with a new request for a different context,
103 * which will cause the hardware to continue executing the second request and queue
104 * the new request (the GPU detects the condition of a context getting preempted
105 * with the same context and optimizes the context switch flow by not doing
106 * preemption, but just sampling the new tail pointer).
109 #include <linux/interrupt.h>
110 #include <linux/string_helpers.h>
112 #include "i915_drv.h"
113 #include "i915_trace.h"
114 #include "i915_vgpu.h"
115 #include "gen8_engine_cs.h"
116 #include "intel_breadcrumbs.h"
117 #include "intel_context.h"
118 #include "intel_engine_heartbeat.h"
119 #include "intel_engine_pm.h"
120 #include "intel_engine_regs.h"
121 #include "intel_engine_stats.h"
122 #include "intel_execlists_submission.h"
123 #include "intel_gt.h"
124 #include "intel_gt_irq.h"
125 #include "intel_gt_pm.h"
126 #include "intel_gt_regs.h"
127 #include "intel_gt_requests.h"
128 #include "intel_lrc.h"
129 #include "intel_lrc_reg.h"
130 #include "intel_mocs.h"
131 #include "intel_reset.h"
132 #include "intel_ring.h"
133 #include "intel_workarounds.h"
134 #include "shmem_utils.h"
136 #define RING_EXECLIST_QFULL (1 << 0x2)
137 #define RING_EXECLIST1_VALID (1 << 0x3)
138 #define RING_EXECLIST0_VALID (1 << 0x4)
139 #define RING_EXECLIST_ACTIVE_STATUS (3 << 0xE)
140 #define RING_EXECLIST1_ACTIVE (1 << 0x11)
141 #define RING_EXECLIST0_ACTIVE (1 << 0x12)
143 #define GEN8_CTX_STATUS_IDLE_ACTIVE (1 << 0)
144 #define GEN8_CTX_STATUS_PREEMPTED (1 << 1)
145 #define GEN8_CTX_STATUS_ELEMENT_SWITCH (1 << 2)
146 #define GEN8_CTX_STATUS_ACTIVE_IDLE (1 << 3)
147 #define GEN8_CTX_STATUS_COMPLETE (1 << 4)
148 #define GEN8_CTX_STATUS_LITE_RESTORE (1 << 15)
150 #define GEN8_CTX_STATUS_COMPLETED_MASK \
151 (GEN8_CTX_STATUS_COMPLETE | GEN8_CTX_STATUS_PREEMPTED)
153 #define GEN12_CTX_STATUS_SWITCHED_TO_NEW_QUEUE (0x1) /* lower csb dword */
154 #define GEN12_CTX_SWITCH_DETAIL(csb_dw) ((csb_dw) & 0xF) /* upper csb dword */
155 #define GEN12_CSB_SW_CTX_ID_MASK GENMASK(25, 15)
156 #define GEN12_IDLE_CTX_ID 0x7FF
157 #define GEN12_CSB_CTX_VALID(csb_dw) \
158 (FIELD_GET(GEN12_CSB_SW_CTX_ID_MASK, csb_dw) != GEN12_IDLE_CTX_ID)
160 #define XEHP_CTX_STATUS_SWITCHED_TO_NEW_QUEUE BIT(1) /* upper csb dword */
161 #define XEHP_CSB_SW_CTX_ID_MASK GENMASK(31, 10)
162 #define XEHP_IDLE_CTX_ID 0xFFFF
163 #define XEHP_CSB_CTX_VALID(csb_dw) \
164 (FIELD_GET(XEHP_CSB_SW_CTX_ID_MASK, csb_dw) != XEHP_IDLE_CTX_ID)
166 /* Typical size of the average request (2 pipecontrols and a MI_BB) */
167 #define EXECLISTS_REQUEST_SIZE 64 /* bytes */
169 struct virtual_engine {
170 struct intel_engine_cs base;
171 struct intel_context context;
175 * We allow only a single request through the virtual engine at a time
176 * (each request in the timeline waits for the completion fence of
177 * the previous before being submitted). By restricting ourselves to
178 * only submitting a single request, each request is placed on to a
179 * physical to maximise load spreading (by virtue of the late greedy
180 * scheduling -- each real engine takes the next available request
183 struct i915_request *request;
186 * We keep a rbtree of available virtual engines inside each physical
187 * engine, sorted by priority. Here we preallocate the nodes we need
188 * for the virtual engine, indexed by physical_engine->id.
193 } nodes[I915_NUM_ENGINES];
195 /* And finally, which physical engines this virtual engine maps onto. */
196 unsigned int num_siblings;
197 struct intel_engine_cs *siblings[];
200 static struct virtual_engine *to_virtual_engine(struct intel_engine_cs *engine)
202 GEM_BUG_ON(!intel_engine_is_virtual(engine));
203 return container_of(engine, struct virtual_engine, base);
206 static struct intel_context *
207 execlists_create_virtual(struct intel_engine_cs **siblings, unsigned int count,
208 unsigned long flags);
210 static struct i915_request *
211 __active_request(const struct intel_timeline * const tl,
212 struct i915_request *rq,
215 struct i915_request *active = rq;
217 list_for_each_entry_from_reverse(rq, &tl->requests, link) {
218 if (__i915_request_is_complete(rq))
222 i915_request_set_error_once(rq, error);
223 __i915_request_skip(rq);
231 static struct i915_request *
232 active_request(const struct intel_timeline * const tl, struct i915_request *rq)
234 return __active_request(tl, rq, 0);
237 static void ring_set_paused(const struct intel_engine_cs *engine, int state)
240 * We inspect HWS_PREEMPT with a semaphore inside
241 * engine->emit_fini_breadcrumb. If the dword is true,
242 * the ring is paused as the semaphore will busywait
243 * until the dword is false.
245 engine->status_page.addr[I915_GEM_HWS_PREEMPT] = state;
250 static struct i915_priolist *to_priolist(struct rb_node *rb)
252 return rb_entry(rb, struct i915_priolist, node);
255 static int rq_prio(const struct i915_request *rq)
257 return READ_ONCE(rq->sched.attr.priority);
260 static int effective_prio(const struct i915_request *rq)
262 int prio = rq_prio(rq);
265 * If this request is special and must not be interrupted at any
266 * cost, so be it. Note we are only checking the most recent request
267 * in the context and so may be masking an earlier vip request. It
268 * is hoped that under the conditions where nopreempt is used, this
269 * will not matter (i.e. all requests to that context will be
270 * nopreempt for as long as desired).
272 if (i915_request_has_nopreempt(rq))
273 prio = I915_PRIORITY_UNPREEMPTABLE;
278 static int queue_prio(const struct i915_sched_engine *sched_engine)
282 rb = rb_first_cached(&sched_engine->queue);
286 return to_priolist(rb)->priority;
289 static int virtual_prio(const struct intel_engine_execlists *el)
291 struct rb_node *rb = rb_first_cached(&el->virtual);
293 return rb ? rb_entry(rb, struct ve_node, rb)->prio : INT_MIN;
296 static bool need_preempt(const struct intel_engine_cs *engine,
297 const struct i915_request *rq)
301 if (!intel_engine_has_semaphores(engine))
305 * Check if the current priority hint merits a preemption attempt.
307 * We record the highest value priority we saw during rescheduling
308 * prior to this dequeue, therefore we know that if it is strictly
309 * less than the current tail of ESLP[0], we do not need to force
310 * a preempt-to-idle cycle.
312 * However, the priority hint is a mere hint that we may need to
313 * preempt. If that hint is stale or we may be trying to preempt
314 * ourselves, ignore the request.
316 * More naturally we would write
317 * prio >= max(0, last);
318 * except that we wish to prevent triggering preemption at the same
319 * priority level: the task that is running should remain running
320 * to preserve FIFO ordering of dependencies.
322 last_prio = max(effective_prio(rq), I915_PRIORITY_NORMAL - 1);
323 if (engine->sched_engine->queue_priority_hint <= last_prio)
327 * Check against the first request in ELSP[1], it will, thanks to the
328 * power of PI, be the highest priority of that context.
330 if (!list_is_last(&rq->sched.link, &engine->sched_engine->requests) &&
331 rq_prio(list_next_entry(rq, sched.link)) > last_prio)
335 * If the inflight context did not trigger the preemption, then maybe
336 * it was the set of queued requests? Pick the highest priority in
337 * the queue (the first active priolist) and see if it deserves to be
338 * running instead of ELSP[0].
340 * The highest priority request in the queue can not be either
341 * ELSP[0] or ELSP[1] as, thanks again to PI, if it was the same
342 * context, it's priority would not exceed ELSP[0] aka last_prio.
344 return max(virtual_prio(&engine->execlists),
345 queue_prio(engine->sched_engine)) > last_prio;
348 __maybe_unused static bool
349 assert_priority_queue(const struct i915_request *prev,
350 const struct i915_request *next)
353 * Without preemption, the prev may refer to the still active element
354 * which we refuse to let go.
356 * Even with preemption, there are times when we think it is better not
357 * to preempt and leave an ostensibly lower priority request in flight.
359 if (i915_request_is_active(prev))
362 return rq_prio(prev) >= rq_prio(next);
365 static struct i915_request *
366 __unwind_incomplete_requests(struct intel_engine_cs *engine)
368 struct i915_request *rq, *rn, *active = NULL;
369 struct list_head *pl;
370 int prio = I915_PRIORITY_INVALID;
372 lockdep_assert_held(&engine->sched_engine->lock);
374 list_for_each_entry_safe_reverse(rq, rn,
375 &engine->sched_engine->requests,
377 if (__i915_request_is_complete(rq)) {
378 list_del_init(&rq->sched.link);
382 __i915_request_unsubmit(rq);
384 GEM_BUG_ON(rq_prio(rq) == I915_PRIORITY_INVALID);
385 if (rq_prio(rq) != prio) {
387 pl = i915_sched_lookup_priolist(engine->sched_engine,
390 GEM_BUG_ON(i915_sched_engine_is_empty(engine->sched_engine));
392 list_move(&rq->sched.link, pl);
393 set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
395 /* Check in case we rollback so far we wrap [size/2] */
396 if (intel_ring_direction(rq->ring,
398 rq->ring->tail + 8) > 0)
399 rq->context->lrc.desc |= CTX_DESC_FORCE_RESTORE;
407 struct i915_request *
408 execlists_unwind_incomplete_requests(struct intel_engine_execlists *execlists)
410 struct intel_engine_cs *engine =
411 container_of(execlists, typeof(*engine), execlists);
413 return __unwind_incomplete_requests(engine);
417 execlists_context_status_change(struct i915_request *rq, unsigned long status)
420 * Only used when GVT-g is enabled now. When GVT-g is disabled,
421 * The compiler should eliminate this function as dead-code.
423 if (!IS_ENABLED(CONFIG_DRM_I915_GVT))
426 atomic_notifier_call_chain(&rq->engine->context_status_notifier,
430 static void reset_active(struct i915_request *rq,
431 struct intel_engine_cs *engine)
433 struct intel_context * const ce = rq->context;
437 * The executing context has been cancelled. We want to prevent
438 * further execution along this context and propagate the error on
439 * to anything depending on its results.
441 * In __i915_request_submit(), we apply the -EIO and remove the
442 * requests' payloads for any banned requests. But first, we must
443 * rewind the context back to the start of the incomplete request so
444 * that we do not jump back into the middle of the batch.
446 * We preserve the breadcrumbs and semaphores of the incomplete
447 * requests so that inter-timeline dependencies (i.e other timelines)
448 * remain correctly ordered. And we defer to __i915_request_submit()
449 * so that all asynchronous waits are correctly handled.
451 ENGINE_TRACE(engine, "{ reset rq=%llx:%lld }\n",
452 rq->fence.context, rq->fence.seqno);
454 /* On resubmission of the active request, payload will be scrubbed */
455 if (__i915_request_is_complete(rq))
458 head = __active_request(ce->timeline, rq, -EIO)->head;
459 head = intel_ring_wrap(ce->ring, head);
461 /* Scrub the context image to prevent replaying the previous batch */
462 lrc_init_regs(ce, engine, true);
464 /* We've switched away, so this should be a no-op, but intent matters */
465 ce->lrc.lrca = lrc_update_regs(ce, engine, head);
468 static bool bad_request(const struct i915_request *rq)
470 return rq->fence.error && i915_request_started(rq);
473 static struct intel_engine_cs *
474 __execlists_schedule_in(struct i915_request *rq)
476 struct intel_engine_cs * const engine = rq->engine;
477 struct intel_context * const ce = rq->context;
479 intel_context_get(ce);
481 if (unlikely(intel_context_is_closed(ce) &&
482 !intel_engine_has_heartbeat(engine)))
483 intel_context_set_banned(ce);
485 if (unlikely(intel_context_is_banned(ce) || bad_request(rq)))
486 reset_active(rq, engine);
488 if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
489 lrc_check_regs(ce, engine, "before");
492 /* Use a fixed tag for OA and friends */
493 GEM_BUG_ON(ce->tag <= BITS_PER_LONG);
494 ce->lrc.ccid = ce->tag;
495 } else if (GRAPHICS_VER_FULL(engine->i915) >= IP_VER(12, 50)) {
496 /* We don't need a strict matching tag, just different values */
497 unsigned int tag = ffs(READ_ONCE(engine->context_tag));
499 GEM_BUG_ON(tag == 0 || tag >= BITS_PER_LONG);
500 clear_bit(tag - 1, &engine->context_tag);
501 ce->lrc.ccid = tag << (XEHP_SW_CTX_ID_SHIFT - 32);
503 BUILD_BUG_ON(BITS_PER_LONG > GEN12_MAX_CONTEXT_HW_ID);
506 /* We don't need a strict matching tag, just different values */
507 unsigned int tag = __ffs(engine->context_tag);
509 GEM_BUG_ON(tag >= BITS_PER_LONG);
510 __clear_bit(tag, &engine->context_tag);
511 ce->lrc.ccid = (1 + tag) << (GEN11_SW_CTX_ID_SHIFT - 32);
513 BUILD_BUG_ON(BITS_PER_LONG > GEN12_MAX_CONTEXT_HW_ID);
516 ce->lrc.ccid |= engine->execlists.ccid;
518 __intel_gt_pm_get(engine->gt);
519 if (engine->fw_domain && !engine->fw_active++)
520 intel_uncore_forcewake_get(engine->uncore, engine->fw_domain);
521 execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_IN);
522 intel_engine_context_in(engine);
524 CE_TRACE(ce, "schedule-in, ccid:%x\n", ce->lrc.ccid);
529 static void execlists_schedule_in(struct i915_request *rq, int idx)
531 struct intel_context * const ce = rq->context;
532 struct intel_engine_cs *old;
534 GEM_BUG_ON(!intel_engine_pm_is_awake(rq->engine));
535 trace_i915_request_in(rq, idx);
539 old = __execlists_schedule_in(rq);
540 WRITE_ONCE(ce->inflight, ptr_inc(old));
542 GEM_BUG_ON(intel_context_inflight(ce) != rq->engine);
546 resubmit_virtual_request(struct i915_request *rq, struct virtual_engine *ve)
548 struct intel_engine_cs *engine = rq->engine;
550 spin_lock_irq(&engine->sched_engine->lock);
552 clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
553 WRITE_ONCE(rq->engine, &ve->base);
554 ve->base.submit_request(rq);
556 spin_unlock_irq(&engine->sched_engine->lock);
559 static void kick_siblings(struct i915_request *rq, struct intel_context *ce)
561 struct virtual_engine *ve = container_of(ce, typeof(*ve), context);
562 struct intel_engine_cs *engine = rq->engine;
565 * After this point, the rq may be transferred to a new sibling, so
566 * before we clear ce->inflight make sure that the context has been
567 * removed from the b->signalers and furthermore we need to make sure
568 * that the concurrent iterator in signal_irq_work is no longer
569 * following ce->signal_link.
571 if (!list_empty(&ce->signals))
572 intel_context_remove_breadcrumbs(ce, engine->breadcrumbs);
575 * This engine is now too busy to run this virtual request, so
576 * see if we can find an alternative engine for it to execute on.
577 * Once a request has become bonded to this engine, we treat it the
578 * same as other native request.
580 if (i915_request_in_priority_queue(rq) &&
581 rq->execution_mask != engine->mask)
582 resubmit_virtual_request(rq, ve);
584 if (READ_ONCE(ve->request))
585 tasklet_hi_schedule(&ve->base.sched_engine->tasklet);
588 static void __execlists_schedule_out(struct i915_request * const rq,
589 struct intel_context * const ce)
591 struct intel_engine_cs * const engine = rq->engine;
595 * NB process_csb() is not under the engine->sched_engine->lock and hence
596 * schedule_out can race with schedule_in meaning that we should
597 * refrain from doing non-trivial work here.
600 CE_TRACE(ce, "schedule-out, ccid:%x\n", ce->lrc.ccid);
601 GEM_BUG_ON(ce->inflight != engine);
603 if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
604 lrc_check_regs(ce, engine, "after");
607 * If we have just completed this context, the engine may now be
608 * idle and we want to re-enter powersaving.
610 if (intel_timeline_is_last(ce->timeline, rq) &&
611 __i915_request_is_complete(rq))
612 intel_engine_add_retire(engine, ce->timeline);
615 if (GRAPHICS_VER_FULL(engine->i915) >= IP_VER(12, 50)) {
616 ccid >>= XEHP_SW_CTX_ID_SHIFT - 32;
617 ccid &= XEHP_MAX_CONTEXT_HW_ID;
619 ccid >>= GEN11_SW_CTX_ID_SHIFT - 32;
620 ccid &= GEN12_MAX_CONTEXT_HW_ID;
623 if (ccid < BITS_PER_LONG) {
624 GEM_BUG_ON(ccid == 0);
625 GEM_BUG_ON(test_bit(ccid - 1, &engine->context_tag));
626 __set_bit(ccid - 1, &engine->context_tag);
628 intel_engine_context_out(engine);
629 execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_OUT);
630 if (engine->fw_domain && !--engine->fw_active)
631 intel_uncore_forcewake_put(engine->uncore, engine->fw_domain);
632 intel_gt_pm_put_async(engine->gt);
635 * If this is part of a virtual engine, its next request may
636 * have been blocked waiting for access to the active context.
637 * We have to kick all the siblings again in case we need to
638 * switch (e.g. the next request is not runnable on this
639 * engine). Hopefully, we will already have submitted the next
640 * request before the tasklet runs and do not need to rebuild
641 * each virtual tree and kick everyone again.
643 if (ce->engine != engine)
644 kick_siblings(rq, ce);
646 WRITE_ONCE(ce->inflight, NULL);
647 intel_context_put(ce);
650 static inline void execlists_schedule_out(struct i915_request *rq)
652 struct intel_context * const ce = rq->context;
654 trace_i915_request_out(rq);
656 GEM_BUG_ON(!ce->inflight);
657 ce->inflight = ptr_dec(ce->inflight);
658 if (!__intel_context_inflight_count(ce->inflight))
659 __execlists_schedule_out(rq, ce);
661 i915_request_put(rq);
664 static u64 execlists_update_context(struct i915_request *rq)
666 struct intel_context *ce = rq->context;
671 if (rq->engine->flags & I915_ENGINE_HAS_EU_PRIORITY)
672 desc |= lrc_desc_priority(rq_prio(rq));
675 * WaIdleLiteRestore:bdw,skl
677 * We should never submit the context with the same RING_TAIL twice
678 * just in case we submit an empty ring, which confuses the HW.
680 * We append a couple of NOOPs (gen8_emit_wa_tail) after the end of
681 * the normal request to be able to always advance the RING_TAIL on
682 * subsequent resubmissions (for lite restore). Should that fail us,
683 * and we try and submit the same tail again, force the context
686 * If we need to return to a preempted context, we need to skip the
687 * lite-restore and force it to reload the RING_TAIL. Otherwise, the
688 * HW has a tendency to ignore us rewinding the TAIL to the end of
689 * an earlier request.
691 GEM_BUG_ON(ce->lrc_reg_state[CTX_RING_TAIL] != rq->ring->tail);
692 prev = rq->ring->tail;
693 tail = intel_ring_set_tail(rq->ring, rq->tail);
694 if (unlikely(intel_ring_direction(rq->ring, tail, prev) <= 0))
695 desc |= CTX_DESC_FORCE_RESTORE;
696 ce->lrc_reg_state[CTX_RING_TAIL] = tail;
697 rq->tail = rq->wa_tail;
700 * Make sure the context image is complete before we submit it to HW.
702 * Ostensibly, writes (including the WCB) should be flushed prior to
703 * an uncached write such as our mmio register access, the empirical
704 * evidence (esp. on Braswell) suggests that the WC write into memory
705 * may not be visible to the HW prior to the completion of the UC
706 * register write and that we may begin execution from the context
707 * before its image is complete leading to invalid PD chasing.
711 ce->lrc.desc &= ~CTX_DESC_FORCE_RESTORE;
715 static void write_desc(struct intel_engine_execlists *execlists, u64 desc, u32 port)
717 if (execlists->ctrl_reg) {
718 writel(lower_32_bits(desc), execlists->submit_reg + port * 2);
719 writel(upper_32_bits(desc), execlists->submit_reg + port * 2 + 1);
721 writel(upper_32_bits(desc), execlists->submit_reg);
722 writel(lower_32_bits(desc), execlists->submit_reg);
726 static __maybe_unused char *
727 dump_port(char *buf, int buflen, const char *prefix, struct i915_request *rq)
732 snprintf(buf, buflen, "%sccid:%x %llx:%lld%s prio %d",
734 rq->context->lrc.ccid,
735 rq->fence.context, rq->fence.seqno,
736 __i915_request_is_complete(rq) ? "!" :
737 __i915_request_has_started(rq) ? "*" :
744 static __maybe_unused noinline void
745 trace_ports(const struct intel_engine_execlists *execlists,
747 struct i915_request * const *ports)
749 const struct intel_engine_cs *engine =
750 container_of(execlists, typeof(*engine), execlists);
751 char __maybe_unused p0[40], p1[40];
756 ENGINE_TRACE(engine, "%s { %s%s }\n", msg,
757 dump_port(p0, sizeof(p0), "", ports[0]),
758 dump_port(p1, sizeof(p1), ", ", ports[1]));
762 reset_in_progress(const struct intel_engine_cs *engine)
764 return unlikely(!__tasklet_is_enabled(&engine->sched_engine->tasklet));
767 static __maybe_unused noinline bool
768 assert_pending_valid(const struct intel_engine_execlists *execlists,
771 struct intel_engine_cs *engine =
772 container_of(execlists, typeof(*engine), execlists);
773 struct i915_request * const *port, *rq, *prev = NULL;
774 struct intel_context *ce = NULL;
777 trace_ports(execlists, msg, execlists->pending);
779 /* We may be messing around with the lists during reset, lalala */
780 if (reset_in_progress(engine))
783 if (!execlists->pending[0]) {
784 GEM_TRACE_ERR("%s: Nothing pending for promotion!\n",
789 if (execlists->pending[execlists_num_ports(execlists)]) {
790 GEM_TRACE_ERR("%s: Excess pending[%d] for promotion!\n",
791 engine->name, execlists_num_ports(execlists));
795 for (port = execlists->pending; (rq = *port); port++) {
799 GEM_BUG_ON(!kref_read(&rq->fence.refcount));
800 GEM_BUG_ON(!i915_request_is_active(rq));
802 if (ce == rq->context) {
803 GEM_TRACE_ERR("%s: Dup context:%llx in pending[%zd]\n",
805 ce->timeline->fence_context,
806 port - execlists->pending);
811 if (ccid == ce->lrc.ccid) {
812 GEM_TRACE_ERR("%s: Dup ccid:%x context:%llx in pending[%zd]\n",
814 ccid, ce->timeline->fence_context,
815 port - execlists->pending);
821 * Sentinels are supposed to be the last request so they flush
822 * the current execution off the HW. Check that they are the only
823 * request in the pending submission.
825 * NB: Due to the async nature of preempt-to-busy and request
826 * cancellation we need to handle the case where request
827 * becomes a sentinel in parallel to CSB processing.
829 if (prev && i915_request_has_sentinel(prev) &&
830 !READ_ONCE(prev->fence.error)) {
831 GEM_TRACE_ERR("%s: context:%llx after sentinel in pending[%zd]\n",
833 ce->timeline->fence_context,
834 port - execlists->pending);
840 * We want virtual requests to only be in the first slot so
841 * that they are never stuck behind a hog and can be immediately
842 * transferred onto the next idle engine.
844 if (rq->execution_mask != engine->mask &&
845 port != execlists->pending) {
846 GEM_TRACE_ERR("%s: virtual engine:%llx not in prime position[%zd]\n",
848 ce->timeline->fence_context,
849 port - execlists->pending);
853 /* Hold tightly onto the lock to prevent concurrent retires! */
854 if (!spin_trylock_irqsave(&rq->lock, flags))
857 if (__i915_request_is_complete(rq))
860 if (i915_active_is_idle(&ce->active) &&
861 !intel_context_is_barrier(ce)) {
862 GEM_TRACE_ERR("%s: Inactive context:%llx in pending[%zd]\n",
864 ce->timeline->fence_context,
865 port - execlists->pending);
870 if (!i915_vma_is_pinned(ce->state)) {
871 GEM_TRACE_ERR("%s: Unpinned context:%llx in pending[%zd]\n",
873 ce->timeline->fence_context,
874 port - execlists->pending);
879 if (!i915_vma_is_pinned(ce->ring->vma)) {
880 GEM_TRACE_ERR("%s: Unpinned ring:%llx in pending[%zd]\n",
882 ce->timeline->fence_context,
883 port - execlists->pending);
889 spin_unlock_irqrestore(&rq->lock, flags);
897 static void execlists_submit_ports(struct intel_engine_cs *engine)
899 struct intel_engine_execlists *execlists = &engine->execlists;
902 GEM_BUG_ON(!assert_pending_valid(execlists, "submit"));
905 * We can skip acquiring intel_runtime_pm_get() here as it was taken
906 * on our behalf by the request (see i915_gem_mark_busy()) and it will
907 * not be relinquished until the device is idle (see
908 * i915_gem_idle_work_handler()). As a precaution, we make sure
909 * that all ELSP are drained i.e. we have processed the CSB,
910 * before allowing ourselves to idle and calling intel_runtime_pm_put().
912 GEM_BUG_ON(!intel_engine_pm_is_awake(engine));
915 * ELSQ note: the submit queue is not cleared after being submitted
916 * to the HW so we need to make sure we always clean it up. This is
917 * currently ensured by the fact that we always write the same number
918 * of elsq entries, keep this in mind before changing the loop below.
920 for (n = execlists_num_ports(execlists); n--; ) {
921 struct i915_request *rq = execlists->pending[n];
923 write_desc(execlists,
924 rq ? execlists_update_context(rq) : 0,
928 /* we need to manually load the submit queue */
929 if (execlists->ctrl_reg)
930 writel(EL_CTRL_LOAD, execlists->ctrl_reg);
933 static bool ctx_single_port_submission(const struct intel_context *ce)
935 return (IS_ENABLED(CONFIG_DRM_I915_GVT) &&
936 intel_context_force_single_submission(ce));
939 static bool can_merge_ctx(const struct intel_context *prev,
940 const struct intel_context *next)
945 if (ctx_single_port_submission(prev))
951 static unsigned long i915_request_flags(const struct i915_request *rq)
953 return READ_ONCE(rq->fence.flags);
956 static bool can_merge_rq(const struct i915_request *prev,
957 const struct i915_request *next)
959 GEM_BUG_ON(prev == next);
960 GEM_BUG_ON(!assert_priority_queue(prev, next));
963 * We do not submit known completed requests. Therefore if the next
964 * request is already completed, we can pretend to merge it in
965 * with the previous context (and we will skip updating the ELSP
966 * and tracking). Thus hopefully keeping the ELSP full with active
967 * contexts, despite the best efforts of preempt-to-busy to confuse
970 if (__i915_request_is_complete(next))
973 if (unlikely((i915_request_flags(prev) | i915_request_flags(next)) &
974 (BIT(I915_FENCE_FLAG_NOPREEMPT) |
975 BIT(I915_FENCE_FLAG_SENTINEL))))
978 if (!can_merge_ctx(prev->context, next->context))
981 GEM_BUG_ON(i915_seqno_passed(prev->fence.seqno, next->fence.seqno));
985 static bool virtual_matches(const struct virtual_engine *ve,
986 const struct i915_request *rq,
987 const struct intel_engine_cs *engine)
989 const struct intel_engine_cs *inflight;
994 if (!(rq->execution_mask & engine->mask)) /* We peeked too soon! */
998 * We track when the HW has completed saving the context image
999 * (i.e. when we have seen the final CS event switching out of
1000 * the context) and must not overwrite the context image before
1001 * then. This restricts us to only using the active engine
1002 * while the previous virtualized request is inflight (so
1003 * we reuse the register offsets). This is a very small
1004 * hystersis on the greedy seelction algorithm.
1006 inflight = intel_context_inflight(&ve->context);
1007 if (inflight && inflight != engine)
1013 static struct virtual_engine *
1014 first_virtual_engine(struct intel_engine_cs *engine)
1016 struct intel_engine_execlists *el = &engine->execlists;
1017 struct rb_node *rb = rb_first_cached(&el->virtual);
1020 struct virtual_engine *ve =
1021 rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
1022 struct i915_request *rq = READ_ONCE(ve->request);
1024 /* lazily cleanup after another engine handled rq */
1025 if (!rq || !virtual_matches(ve, rq, engine)) {
1026 rb_erase_cached(rb, &el->virtual);
1028 rb = rb_first_cached(&el->virtual);
1038 static void virtual_xfer_context(struct virtual_engine *ve,
1039 struct intel_engine_cs *engine)
1043 if (likely(engine == ve->siblings[0]))
1046 GEM_BUG_ON(READ_ONCE(ve->context.inflight));
1047 if (!intel_engine_has_relative_mmio(engine))
1048 lrc_update_offsets(&ve->context, engine);
1051 * Move the bound engine to the top of the list for
1052 * future execution. We then kick this tasklet first
1053 * before checking others, so that we preferentially
1054 * reuse this set of bound registers.
1056 for (n = 1; n < ve->num_siblings; n++) {
1057 if (ve->siblings[n] == engine) {
1058 swap(ve->siblings[n], ve->siblings[0]);
1064 static void defer_request(struct i915_request *rq, struct list_head * const pl)
1069 * We want to move the interrupted request to the back of
1070 * the round-robin list (i.e. its priority level), but
1071 * in doing so, we must then move all requests that were in
1072 * flight and were waiting for the interrupted request to
1073 * be run after it again.
1076 struct i915_dependency *p;
1078 GEM_BUG_ON(i915_request_is_active(rq));
1079 list_move_tail(&rq->sched.link, pl);
1081 for_each_waiter(p, rq) {
1082 struct i915_request *w =
1083 container_of(p->waiter, typeof(*w), sched);
1085 if (p->flags & I915_DEPENDENCY_WEAK)
1088 /* Leave semaphores spinning on the other engines */
1089 if (w->engine != rq->engine)
1092 /* No waiter should start before its signaler */
1093 GEM_BUG_ON(i915_request_has_initial_breadcrumb(w) &&
1094 __i915_request_has_started(w) &&
1095 !__i915_request_is_complete(rq));
1097 if (!i915_request_is_ready(w))
1100 if (rq_prio(w) < rq_prio(rq))
1103 GEM_BUG_ON(rq_prio(w) > rq_prio(rq));
1104 GEM_BUG_ON(i915_request_is_active(w));
1105 list_move_tail(&w->sched.link, &list);
1108 rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
1112 static void defer_active(struct intel_engine_cs *engine)
1114 struct i915_request *rq;
1116 rq = __unwind_incomplete_requests(engine);
1120 defer_request(rq, i915_sched_lookup_priolist(engine->sched_engine,
1125 timeslice_yield(const struct intel_engine_execlists *el,
1126 const struct i915_request *rq)
1129 * Once bitten, forever smitten!
1131 * If the active context ever busy-waited on a semaphore,
1132 * it will be treated as a hog until the end of its timeslice (i.e.
1133 * until it is scheduled out and replaced by a new submission,
1134 * possibly even its own lite-restore). The HW only sends an interrupt
1135 * on the first miss, and we do know if that semaphore has been
1136 * signaled, or even if it is now stuck on another semaphore. Play
1137 * safe, yield if it might be stuck -- it will be given a fresh
1138 * timeslice in the near future.
1140 return rq->context->lrc.ccid == READ_ONCE(el->yield);
1143 static bool needs_timeslice(const struct intel_engine_cs *engine,
1144 const struct i915_request *rq)
1146 if (!intel_engine_has_timeslices(engine))
1149 /* If not currently active, or about to switch, wait for next event */
1150 if (!rq || __i915_request_is_complete(rq))
1153 /* We do not need to start the timeslice until after the ACK */
1154 if (READ_ONCE(engine->execlists.pending[0]))
1157 /* If ELSP[1] is occupied, always check to see if worth slicing */
1158 if (!list_is_last_rcu(&rq->sched.link,
1159 &engine->sched_engine->requests)) {
1160 ENGINE_TRACE(engine, "timeslice required for second inflight context\n");
1164 /* Otherwise, ELSP[0] is by itself, but may be waiting in the queue */
1165 if (!i915_sched_engine_is_empty(engine->sched_engine)) {
1166 ENGINE_TRACE(engine, "timeslice required for queue\n");
1170 if (!RB_EMPTY_ROOT(&engine->execlists.virtual.rb_root)) {
1171 ENGINE_TRACE(engine, "timeslice required for virtual\n");
1179 timeslice_expired(struct intel_engine_cs *engine, const struct i915_request *rq)
1181 const struct intel_engine_execlists *el = &engine->execlists;
1183 if (i915_request_has_nopreempt(rq) && __i915_request_has_started(rq))
1186 if (!needs_timeslice(engine, rq))
1189 return timer_expired(&el->timer) || timeslice_yield(el, rq);
1192 static unsigned long timeslice(const struct intel_engine_cs *engine)
1194 return READ_ONCE(engine->props.timeslice_duration_ms);
1197 static void start_timeslice(struct intel_engine_cs *engine)
1199 struct intel_engine_execlists *el = &engine->execlists;
1200 unsigned long duration;
1202 /* Disable the timer if there is nothing to switch to */
1204 if (needs_timeslice(engine, *el->active)) {
1205 /* Avoid continually prolonging an active timeslice */
1206 if (timer_active(&el->timer)) {
1208 * If we just submitted a new ELSP after an old
1209 * context, that context may have already consumed
1210 * its timeslice, so recheck.
1212 if (!timer_pending(&el->timer))
1213 tasklet_hi_schedule(&engine->sched_engine->tasklet);
1217 duration = timeslice(engine);
1220 set_timer_ms(&el->timer, duration);
1223 static void record_preemption(struct intel_engine_execlists *execlists)
1225 (void)I915_SELFTEST_ONLY(execlists->preempt_hang.count++);
1228 static unsigned long active_preempt_timeout(struct intel_engine_cs *engine,
1229 const struct i915_request *rq)
1234 /* Force a fast reset for terminated contexts (ignoring sysfs!) */
1235 if (unlikely(intel_context_is_banned(rq->context) || bad_request(rq)))
1238 return READ_ONCE(engine->props.preempt_timeout_ms);
1241 static void set_preempt_timeout(struct intel_engine_cs *engine,
1242 const struct i915_request *rq)
1244 if (!intel_engine_has_preempt_reset(engine))
1247 set_timer_ms(&engine->execlists.preempt,
1248 active_preempt_timeout(engine, rq));
1251 static bool completed(const struct i915_request *rq)
1253 if (i915_request_has_sentinel(rq))
1256 return __i915_request_is_complete(rq);
1259 static void execlists_dequeue(struct intel_engine_cs *engine)
1261 struct intel_engine_execlists * const execlists = &engine->execlists;
1262 struct i915_sched_engine * const sched_engine = engine->sched_engine;
1263 struct i915_request **port = execlists->pending;
1264 struct i915_request ** const last_port = port + execlists->port_mask;
1265 struct i915_request *last, * const *active;
1266 struct virtual_engine *ve;
1268 bool submit = false;
1271 * Hardware submission is through 2 ports. Conceptually each port
1272 * has a (RING_START, RING_HEAD, RING_TAIL) tuple. RING_START is
1273 * static for a context, and unique to each, so we only execute
1274 * requests belonging to a single context from each ring. RING_HEAD
1275 * is maintained by the CS in the context image, it marks the place
1276 * where it got up to last time, and through RING_TAIL we tell the CS
1277 * where we want to execute up to this time.
1279 * In this list the requests are in order of execution. Consecutive
1280 * requests from the same context are adjacent in the ringbuffer. We
1281 * can combine these requests into a single RING_TAIL update:
1283 * RING_HEAD...req1...req2
1285 * since to execute req2 the CS must first execute req1.
1287 * Our goal then is to point each port to the end of a consecutive
1288 * sequence of requests as being the most optimal (fewest wake ups
1289 * and context switches) submission.
1292 spin_lock(&sched_engine->lock);
1295 * If the queue is higher priority than the last
1296 * request in the currently active context, submit afresh.
1297 * We will resubmit again afterwards in case we need to split
1298 * the active context to interject the preemption request,
1299 * i.e. we will retrigger preemption following the ack in case
1303 active = execlists->active;
1304 while ((last = *active) && completed(last))
1308 if (need_preempt(engine, last)) {
1309 ENGINE_TRACE(engine,
1310 "preempting last=%llx:%lld, prio=%d, hint=%d\n",
1311 last->fence.context,
1313 last->sched.attr.priority,
1314 sched_engine->queue_priority_hint);
1315 record_preemption(execlists);
1318 * Don't let the RING_HEAD advance past the breadcrumb
1319 * as we unwind (and until we resubmit) so that we do
1320 * not accidentally tell it to go backwards.
1322 ring_set_paused(engine, 1);
1325 * Note that we have not stopped the GPU at this point,
1326 * so we are unwinding the incomplete requests as they
1327 * remain inflight and so by the time we do complete
1328 * the preemption, some of the unwound requests may
1331 __unwind_incomplete_requests(engine);
1334 } else if (timeslice_expired(engine, last)) {
1335 ENGINE_TRACE(engine,
1336 "expired:%s last=%llx:%lld, prio=%d, hint=%d, yield?=%s\n",
1337 str_yes_no(timer_expired(&execlists->timer)),
1338 last->fence.context, last->fence.seqno,
1340 sched_engine->queue_priority_hint,
1341 str_yes_no(timeslice_yield(execlists, last)));
1344 * Consume this timeslice; ensure we start a new one.
1346 * The timeslice expired, and we will unwind the
1347 * running contexts and recompute the next ELSP.
1348 * If that submit will be the same pair of contexts
1349 * (due to dependency ordering), we will skip the
1350 * submission. If we don't cancel the timer now,
1351 * we will see that the timer has expired and
1352 * reschedule the tasklet; continually until the
1353 * next context switch or other preeemption event.
1355 * Since we have decided to reschedule based on
1356 * consumption of this timeslice, if we submit the
1357 * same context again, grant it a full timeslice.
1359 cancel_timer(&execlists->timer);
1360 ring_set_paused(engine, 1);
1361 defer_active(engine);
1364 * Unlike for preemption, if we rewind and continue
1365 * executing the same context as previously active,
1366 * the order of execution will remain the same and
1367 * the tail will only advance. We do not need to
1368 * force a full context restore, as a lite-restore
1369 * is sufficient to resample the monotonic TAIL.
1371 * If we switch to any other context, similarly we
1372 * will not rewind TAIL of current context, and
1373 * normal save/restore will preserve state and allow
1374 * us to later continue executing the same request.
1379 * Otherwise if we already have a request pending
1380 * for execution after the current one, we can
1381 * just wait until the next CS event before
1382 * queuing more. In either case we will force a
1383 * lite-restore preemption event, but if we wait
1384 * we hopefully coalesce several updates into a single
1389 * Even if ELSP[1] is occupied and not worthy
1390 * of timeslices, our queue might be.
1392 spin_unlock(&sched_engine->lock);
1398 /* XXX virtual is always taking precedence */
1399 while ((ve = first_virtual_engine(engine))) {
1400 struct i915_request *rq;
1402 spin_lock(&ve->base.sched_engine->lock);
1405 if (unlikely(!virtual_matches(ve, rq, engine)))
1406 goto unlock; /* lost the race to a sibling */
1408 GEM_BUG_ON(rq->engine != &ve->base);
1409 GEM_BUG_ON(rq->context != &ve->context);
1411 if (unlikely(rq_prio(rq) < queue_prio(sched_engine))) {
1412 spin_unlock(&ve->base.sched_engine->lock);
1416 if (last && !can_merge_rq(last, rq)) {
1417 spin_unlock(&ve->base.sched_engine->lock);
1418 spin_unlock(&engine->sched_engine->lock);
1419 return; /* leave this for another sibling */
1422 ENGINE_TRACE(engine,
1423 "virtual rq=%llx:%lld%s, new engine? %s\n",
1426 __i915_request_is_complete(rq) ? "!" :
1427 __i915_request_has_started(rq) ? "*" :
1429 str_yes_no(engine != ve->siblings[0]));
1431 WRITE_ONCE(ve->request, NULL);
1432 WRITE_ONCE(ve->base.sched_engine->queue_priority_hint, INT_MIN);
1434 rb = &ve->nodes[engine->id].rb;
1435 rb_erase_cached(rb, &execlists->virtual);
1438 GEM_BUG_ON(!(rq->execution_mask & engine->mask));
1439 WRITE_ONCE(rq->engine, engine);
1441 if (__i915_request_submit(rq)) {
1443 * Only after we confirm that we will submit
1444 * this request (i.e. it has not already
1445 * completed), do we want to update the context.
1447 * This serves two purposes. It avoids
1448 * unnecessary work if we are resubmitting an
1449 * already completed request after timeslicing.
1450 * But more importantly, it prevents us altering
1451 * ve->siblings[] on an idle context, where
1452 * we may be using ve->siblings[] in
1453 * virtual_context_enter / virtual_context_exit.
1455 virtual_xfer_context(ve, engine);
1456 GEM_BUG_ON(ve->siblings[0] != engine);
1462 i915_request_put(rq);
1464 spin_unlock(&ve->base.sched_engine->lock);
1467 * Hmm, we have a bunch of virtual engine requests,
1468 * but the first one was already completed (thanks
1469 * preempt-to-busy!). Keep looking at the veng queue
1470 * until we have no more relevant requests (i.e.
1471 * the normal submit queue has higher priority).
1477 while ((rb = rb_first_cached(&sched_engine->queue))) {
1478 struct i915_priolist *p = to_priolist(rb);
1479 struct i915_request *rq, *rn;
1481 priolist_for_each_request_consume(rq, rn, p) {
1485 * Can we combine this request with the current port?
1486 * It has to be the same context/ringbuffer and not
1487 * have any exceptions (e.g. GVT saying never to
1488 * combine contexts).
1490 * If we can combine the requests, we can execute both
1491 * by updating the RING_TAIL to point to the end of the
1492 * second request, and so we never need to tell the
1493 * hardware about the first.
1495 if (last && !can_merge_rq(last, rq)) {
1497 * If we are on the second port and cannot
1498 * combine this request with the last, then we
1501 if (port == last_port)
1505 * We must not populate both ELSP[] with the
1506 * same LRCA, i.e. we must submit 2 different
1507 * contexts if we submit 2 ELSP.
1509 if (last->context == rq->context)
1512 if (i915_request_has_sentinel(last))
1516 * We avoid submitting virtual requests into
1517 * the secondary ports so that we can migrate
1518 * the request immediately to another engine
1519 * rather than wait for the primary request.
1521 if (rq->execution_mask != engine->mask)
1525 * If GVT overrides us we only ever submit
1526 * port[0], leaving port[1] empty. Note that we
1527 * also have to be careful that we don't queue
1528 * the same context (even though a different
1529 * request) to the second port.
1531 if (ctx_single_port_submission(last->context) ||
1532 ctx_single_port_submission(rq->context))
1538 if (__i915_request_submit(rq)) {
1540 *port++ = i915_request_get(last);
1545 !can_merge_ctx(last->context,
1548 i915_seqno_passed(last->fence.seqno,
1556 rb_erase_cached(&p->node, &sched_engine->queue);
1557 i915_priolist_free(p);
1560 *port++ = i915_request_get(last);
1563 * Here be a bit of magic! Or sleight-of-hand, whichever you prefer.
1565 * We choose the priority hint such that if we add a request of greater
1566 * priority than this, we kick the submission tasklet to decide on
1567 * the right order of submitting the requests to hardware. We must
1568 * also be prepared to reorder requests as they are in-flight on the
1569 * HW. We derive the priority hint then as the first "hole" in
1570 * the HW submission ports and if there are no available slots,
1571 * the priority of the lowest executing request, i.e. last.
1573 * When we do receive a higher priority request ready to run from the
1574 * user, see queue_request(), the priority hint is bumped to that
1575 * request triggering preemption on the next dequeue (or subsequent
1576 * interrupt for secondary ports).
1578 sched_engine->queue_priority_hint = queue_prio(sched_engine);
1579 i915_sched_engine_reset_on_empty(sched_engine);
1580 spin_unlock(&sched_engine->lock);
1583 * We can skip poking the HW if we ended up with exactly the same set
1584 * of requests as currently running, e.g. trying to timeslice a pair
1585 * of ordered contexts.
1590 (port - execlists->pending) * sizeof(*port))) {
1592 while (port-- != execlists->pending)
1593 execlists_schedule_in(*port, port - execlists->pending);
1595 WRITE_ONCE(execlists->yield, -1);
1596 set_preempt_timeout(engine, *active);
1597 execlists_submit_ports(engine);
1599 ring_set_paused(engine, 0);
1600 while (port-- != execlists->pending)
1601 i915_request_put(*port);
1602 *execlists->pending = NULL;
1606 static void execlists_dequeue_irq(struct intel_engine_cs *engine)
1608 local_irq_disable(); /* Suspend interrupts across request submission */
1609 execlists_dequeue(engine);
1610 local_irq_enable(); /* flush irq_work (e.g. breadcrumb enabling) */
1613 static void clear_ports(struct i915_request **ports, int count)
1615 memset_p((void **)ports, NULL, count);
1619 copy_ports(struct i915_request **dst, struct i915_request **src, int count)
1621 /* A memcpy_p() would be very useful here! */
1623 WRITE_ONCE(*dst++, *src++); /* avoid write tearing */
1626 static struct i915_request **
1627 cancel_port_requests(struct intel_engine_execlists * const execlists,
1628 struct i915_request **inactive)
1630 struct i915_request * const *port;
1632 for (port = execlists->pending; *port; port++)
1633 *inactive++ = *port;
1634 clear_ports(execlists->pending, ARRAY_SIZE(execlists->pending));
1636 /* Mark the end of active before we overwrite *active */
1637 for (port = xchg(&execlists->active, execlists->pending); *port; port++)
1638 *inactive++ = *port;
1639 clear_ports(execlists->inflight, ARRAY_SIZE(execlists->inflight));
1641 smp_wmb(); /* complete the seqlock for execlists_active() */
1642 WRITE_ONCE(execlists->active, execlists->inflight);
1644 /* Having cancelled all outstanding process_csb(), stop their timers */
1645 GEM_BUG_ON(execlists->pending[0]);
1646 cancel_timer(&execlists->timer);
1647 cancel_timer(&execlists->preempt);
1653 * Starting with Gen12, the status has a new format:
1655 * bit 0: switched to new queue
1657 * bit 2: semaphore wait mode (poll or signal), only valid when
1658 * switch detail is set to "wait on semaphore"
1659 * bits 3-5: engine class
1660 * bits 6-11: engine instance
1661 * bits 12-14: reserved
1662 * bits 15-25: sw context id of the lrc the GT switched to
1663 * bits 26-31: sw counter of the lrc the GT switched to
1664 * bits 32-35: context switch detail
1666 * - 1: wait on sync flip
1667 * - 2: wait on vblank
1668 * - 3: wait on scanline
1669 * - 4: wait on semaphore
1670 * - 5: context preempted (not on SEMAPHORE_WAIT or
1673 * bits 37-43: wait detail (for switch detail 1 to 4)
1674 * bits 44-46: reserved
1675 * bits 47-57: sw context id of the lrc the GT switched away from
1676 * bits 58-63: sw counter of the lrc the GT switched away from
1678 * Xe_HP csb shuffles things around compared to TGL:
1680 * bits 0-3: context switch detail (same possible values as TGL)
1681 * bits 4-9: engine instance
1682 * bits 10-25: sw context id of the lrc the GT switched to
1683 * bits 26-31: sw counter of the lrc the GT switched to
1684 * bit 32: semaphore wait mode (poll or signal), Only valid when
1685 * switch detail is set to "wait on semaphore"
1686 * bit 33: switched to new queue
1687 * bits 34-41: wait detail (for switch detail 1 to 4)
1688 * bits 42-57: sw context id of the lrc the GT switched away from
1689 * bits 58-63: sw counter of the lrc the GT switched away from
1692 __gen12_csb_parse(bool ctx_to_valid, bool ctx_away_valid, bool new_queue,
1696 * The context switch detail is not guaranteed to be 5 when a preemption
1697 * occurs, so we can't just check for that. The check below works for
1698 * all the cases we care about, including preemptions of WAIT
1699 * instructions and lite-restore. Preempt-to-idle via the CTRL register
1700 * would require some extra handling, but we don't support that.
1702 if (!ctx_away_valid || new_queue) {
1703 GEM_BUG_ON(!ctx_to_valid);
1708 * switch detail = 5 is covered by the case above and we do not expect a
1709 * context switch on an unsuccessful wait instruction since we always
1712 GEM_BUG_ON(switch_detail);
1716 static bool xehp_csb_parse(const u64 csb)
1718 return __gen12_csb_parse(XEHP_CSB_CTX_VALID(lower_32_bits(csb)), /* cxt to */
1719 XEHP_CSB_CTX_VALID(upper_32_bits(csb)), /* cxt away */
1720 upper_32_bits(csb) & XEHP_CTX_STATUS_SWITCHED_TO_NEW_QUEUE,
1721 GEN12_CTX_SWITCH_DETAIL(lower_32_bits(csb)));
1724 static bool gen12_csb_parse(const u64 csb)
1726 return __gen12_csb_parse(GEN12_CSB_CTX_VALID(lower_32_bits(csb)), /* cxt to */
1727 GEN12_CSB_CTX_VALID(upper_32_bits(csb)), /* cxt away */
1728 lower_32_bits(csb) & GEN12_CTX_STATUS_SWITCHED_TO_NEW_QUEUE,
1729 GEN12_CTX_SWITCH_DETAIL(upper_32_bits(csb)));
1732 static bool gen8_csb_parse(const u64 csb)
1734 return csb & (GEN8_CTX_STATUS_IDLE_ACTIVE | GEN8_CTX_STATUS_PREEMPTED);
1738 wa_csb_read(const struct intel_engine_cs *engine, u64 * const csb)
1743 * Reading from the HWSP has one particular advantage: we can detect
1744 * a stale entry. Since the write into HWSP is broken, we have no reason
1745 * to trust the HW at all, the mmio entry may equally be unordered, so
1746 * we prefer the path that is self-checking and as a last resort,
1747 * return the mmio value.
1749 * tgl,dg1:HSDES#22011327657
1752 if (wait_for_atomic_us((entry = READ_ONCE(*csb)) != -1, 10)) {
1753 int idx = csb - engine->execlists.csb_status;
1756 status = GEN8_EXECLISTS_STATUS_BUF;
1758 status = GEN11_EXECLISTS_STATUS_BUF2;
1761 status += sizeof(u64) * idx;
1763 entry = intel_uncore_read64(engine->uncore,
1764 _MMIO(engine->mmio_base + status));
1771 static u64 csb_read(const struct intel_engine_cs *engine, u64 * const csb)
1773 u64 entry = READ_ONCE(*csb);
1776 * Unfortunately, the GPU does not always serialise its write
1777 * of the CSB entries before its write of the CSB pointer, at least
1778 * from the perspective of the CPU, using what is known as a Global
1779 * Observation Point. We may read a new CSB tail pointer, but then
1780 * read the stale CSB entries, causing us to misinterpret the
1781 * context-switch events, and eventually declare the GPU hung.
1783 * icl:HSDES#1806554093
1784 * tgl:HSDES#22011248461
1786 if (unlikely(entry == -1))
1787 entry = wa_csb_read(engine, csb);
1789 /* Consume this entry so that we can spot its future reuse. */
1790 WRITE_ONCE(*csb, -1);
1792 /* ELSP is an implicit wmb() before the GPU wraps and overwrites csb */
1796 static void new_timeslice(struct intel_engine_execlists *el)
1798 /* By cancelling, we will start afresh in start_timeslice() */
1799 cancel_timer(&el->timer);
1802 static struct i915_request **
1803 process_csb(struct intel_engine_cs *engine, struct i915_request **inactive)
1805 struct intel_engine_execlists * const execlists = &engine->execlists;
1806 u64 * const buf = execlists->csb_status;
1807 const u8 num_entries = execlists->csb_size;
1808 struct i915_request **prev;
1812 * As we modify our execlists state tracking we require exclusive
1813 * access. Either we are inside the tasklet, or the tasklet is disabled
1814 * and we assume that is only inside the reset paths and so serialised.
1816 GEM_BUG_ON(!tasklet_is_locked(&engine->sched_engine->tasklet) &&
1817 !reset_in_progress(engine));
1820 * Note that csb_write, csb_status may be either in HWSP or mmio.
1821 * When reading from the csb_write mmio register, we have to be
1822 * careful to only use the GEN8_CSB_WRITE_PTR portion, which is
1823 * the low 4bits. As it happens we know the next 4bits are always
1824 * zero and so we can simply masked off the low u8 of the register
1825 * and treat it identically to reading from the HWSP (without having
1826 * to use explicit shifting and masking, and probably bifurcating
1827 * the code to handle the legacy mmio read).
1829 head = execlists->csb_head;
1830 tail = READ_ONCE(*execlists->csb_write);
1831 if (unlikely(head == tail))
1835 * We will consume all events from HW, or at least pretend to.
1837 * The sequence of events from the HW is deterministic, and derived
1838 * from our writes to the ELSP, with a smidgen of variability for
1839 * the arrival of the asynchronous requests wrt to the inflight
1840 * execution. If the HW sends an event that does not correspond with
1841 * the one we are expecting, we have to abandon all hope as we lose
1842 * all tracking of what the engine is actually executing. We will
1843 * only detect we are out of sequence with the HW when we get an
1844 * 'impossible' event because we have already drained our own
1845 * preemption/promotion queue. If this occurs, we know that we likely
1846 * lost track of execution earlier and must unwind and restart, the
1847 * simplest way is by stop processing the event queue and force the
1850 execlists->csb_head = tail;
1851 ENGINE_TRACE(engine, "cs-irq head=%d, tail=%d\n", head, tail);
1854 * Hopefully paired with a wmb() in HW!
1856 * We must complete the read of the write pointer before any reads
1857 * from the CSB, so that we do not see stale values. Without an rmb
1858 * (lfence) the HW may speculatively perform the CSB[] reads *before*
1859 * we perform the READ_ONCE(*csb_write).
1863 /* Remember who was last running under the timer */
1871 if (++head == num_entries)
1875 * We are flying near dragons again.
1877 * We hold a reference to the request in execlist_port[]
1878 * but no more than that. We are operating in softirq
1879 * context and so cannot hold any mutex or sleep. That
1880 * prevents us stopping the requests we are processing
1881 * in port[] from being retired simultaneously (the
1882 * breadcrumb will be complete before we see the
1883 * context-switch). As we only hold the reference to the
1884 * request, any pointer chasing underneath the request
1885 * is subject to a potential use-after-free. Thus we
1886 * store all of the bookkeeping within port[] as
1887 * required, and avoid using unguarded pointers beneath
1888 * request itself. The same applies to the atomic
1892 csb = csb_read(engine, buf + head);
1893 ENGINE_TRACE(engine, "csb[%d]: status=0x%08x:0x%08x\n",
1894 head, upper_32_bits(csb), lower_32_bits(csb));
1896 if (GRAPHICS_VER_FULL(engine->i915) >= IP_VER(12, 50))
1897 promote = xehp_csb_parse(csb);
1898 else if (GRAPHICS_VER(engine->i915) >= 12)
1899 promote = gen12_csb_parse(csb);
1901 promote = gen8_csb_parse(csb);
1903 struct i915_request * const *old = execlists->active;
1905 if (GEM_WARN_ON(!*execlists->pending)) {
1906 execlists->error_interrupt |= ERROR_CSB;
1910 ring_set_paused(engine, 0);
1912 /* Point active to the new ELSP; prevent overwriting */
1913 WRITE_ONCE(execlists->active, execlists->pending);
1914 smp_wmb(); /* notify execlists_active() */
1916 /* cancel old inflight, prepare for switch */
1917 trace_ports(execlists, "preempted", old);
1919 *inactive++ = *old++;
1921 /* switch pending to inflight */
1922 GEM_BUG_ON(!assert_pending_valid(execlists, "promote"));
1923 copy_ports(execlists->inflight,
1925 execlists_num_ports(execlists));
1926 smp_wmb(); /* complete the seqlock */
1927 WRITE_ONCE(execlists->active, execlists->inflight);
1929 /* XXX Magic delay for tgl */
1930 ENGINE_POSTING_READ(engine, RING_CONTEXT_STATUS_PTR);
1932 WRITE_ONCE(execlists->pending[0], NULL);
1934 if (GEM_WARN_ON(!*execlists->active)) {
1935 execlists->error_interrupt |= ERROR_CSB;
1939 /* port0 completed, advanced to port1 */
1940 trace_ports(execlists, "completed", execlists->active);
1943 * We rely on the hardware being strongly
1944 * ordered, that the breadcrumb write is
1945 * coherent (visible from the CPU) before the
1946 * user interrupt is processed. One might assume
1947 * that the breadcrumb write being before the
1948 * user interrupt and the CS event for the context
1949 * switch would therefore be before the CS event
1952 if (GEM_SHOW_DEBUG() &&
1953 !__i915_request_is_complete(*execlists->active)) {
1954 struct i915_request *rq = *execlists->active;
1955 const u32 *regs __maybe_unused =
1956 rq->context->lrc_reg_state;
1958 ENGINE_TRACE(engine,
1959 "context completed before request!\n");
1960 ENGINE_TRACE(engine,
1961 "ring:{start:0x%08x, head:%04x, tail:%04x, ctl:%08x, mode:%08x}\n",
1962 ENGINE_READ(engine, RING_START),
1963 ENGINE_READ(engine, RING_HEAD) & HEAD_ADDR,
1964 ENGINE_READ(engine, RING_TAIL) & TAIL_ADDR,
1965 ENGINE_READ(engine, RING_CTL),
1966 ENGINE_READ(engine, RING_MI_MODE));
1967 ENGINE_TRACE(engine,
1968 "rq:{start:%08x, head:%04x, tail:%04x, seqno:%llx:%d, hwsp:%d}, ",
1969 i915_ggtt_offset(rq->ring->vma),
1972 lower_32_bits(rq->fence.seqno),
1974 ENGINE_TRACE(engine,
1975 "ctx:{start:%08x, head:%04x, tail:%04x}, ",
1976 regs[CTX_RING_START],
1977 regs[CTX_RING_HEAD],
1978 regs[CTX_RING_TAIL]);
1981 *inactive++ = *execlists->active++;
1983 GEM_BUG_ON(execlists->active - execlists->inflight >
1984 execlists_num_ports(execlists));
1986 } while (head != tail);
1989 * Gen11 has proven to fail wrt global observation point between
1990 * entry and tail update, failing on the ordering and thus
1991 * we see an old entry in the context status buffer.
1993 * Forcibly evict out entries for the next gpu csb update,
1994 * to increase the odds that we get a fresh entries with non
1995 * working hardware. The cost for doing so comes out mostly with
1996 * the wash as hardware, working or not, will need to do the
1997 * invalidation before.
1999 drm_clflush_virt_range(&buf[0], num_entries * sizeof(buf[0]));
2002 * We assume that any event reflects a change in context flow
2003 * and merits a fresh timeslice. We reinstall the timer after
2004 * inspecting the queue to see if we need to resumbit.
2006 if (*prev != *execlists->active) { /* elide lite-restores */
2008 * Note the inherent discrepancy between the HW runtime,
2009 * recorded as part of the context switch, and the CPU
2010 * adjustment for active contexts. We have to hope that
2011 * the delay in processing the CS event is very small
2012 * and consistent. It works to our advantage to have
2013 * the CPU adjustment _undershoot_ (i.e. start later than)
2014 * the CS timestamp so we never overreport the runtime
2015 * and correct overselves later when updating from HW.
2018 lrc_runtime_stop((*prev)->context);
2019 if (*execlists->active)
2020 lrc_runtime_start((*execlists->active)->context);
2021 new_timeslice(execlists);
2027 static void post_process_csb(struct i915_request **port,
2028 struct i915_request **last)
2030 while (port != last)
2031 execlists_schedule_out(*port++);
2034 static void __execlists_hold(struct i915_request *rq)
2039 struct i915_dependency *p;
2041 if (i915_request_is_active(rq))
2042 __i915_request_unsubmit(rq);
2044 clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
2045 list_move_tail(&rq->sched.link,
2046 &rq->engine->sched_engine->hold);
2047 i915_request_set_hold(rq);
2048 RQ_TRACE(rq, "on hold\n");
2050 for_each_waiter(p, rq) {
2051 struct i915_request *w =
2052 container_of(p->waiter, typeof(*w), sched);
2054 if (p->flags & I915_DEPENDENCY_WEAK)
2057 /* Leave semaphores spinning on the other engines */
2058 if (w->engine != rq->engine)
2061 if (!i915_request_is_ready(w))
2064 if (__i915_request_is_complete(w))
2067 if (i915_request_on_hold(w))
2070 list_move_tail(&w->sched.link, &list);
2073 rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
2077 static bool execlists_hold(struct intel_engine_cs *engine,
2078 struct i915_request *rq)
2080 if (i915_request_on_hold(rq))
2083 spin_lock_irq(&engine->sched_engine->lock);
2085 if (__i915_request_is_complete(rq)) { /* too late! */
2091 * Transfer this request onto the hold queue to prevent it
2092 * being resumbitted to HW (and potentially completed) before we have
2093 * released it. Since we may have already submitted following
2094 * requests, we need to remove those as well.
2096 GEM_BUG_ON(i915_request_on_hold(rq));
2097 GEM_BUG_ON(rq->engine != engine);
2098 __execlists_hold(rq);
2099 GEM_BUG_ON(list_empty(&engine->sched_engine->hold));
2102 spin_unlock_irq(&engine->sched_engine->lock);
2106 static bool hold_request(const struct i915_request *rq)
2108 struct i915_dependency *p;
2109 bool result = false;
2112 * If one of our ancestors is on hold, we must also be on hold,
2113 * otherwise we will bypass it and execute before it.
2116 for_each_signaler(p, rq) {
2117 const struct i915_request *s =
2118 container_of(p->signaler, typeof(*s), sched);
2120 if (s->engine != rq->engine)
2123 result = i915_request_on_hold(s);
2132 static void __execlists_unhold(struct i915_request *rq)
2137 struct i915_dependency *p;
2139 RQ_TRACE(rq, "hold release\n");
2141 GEM_BUG_ON(!i915_request_on_hold(rq));
2142 GEM_BUG_ON(!i915_sw_fence_signaled(&rq->submit));
2144 i915_request_clear_hold(rq);
2145 list_move_tail(&rq->sched.link,
2146 i915_sched_lookup_priolist(rq->engine->sched_engine,
2148 set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
2150 /* Also release any children on this engine that are ready */
2151 for_each_waiter(p, rq) {
2152 struct i915_request *w =
2153 container_of(p->waiter, typeof(*w), sched);
2155 if (p->flags & I915_DEPENDENCY_WEAK)
2158 if (w->engine != rq->engine)
2161 if (!i915_request_on_hold(w))
2164 /* Check that no other parents are also on hold */
2165 if (hold_request(w))
2168 list_move_tail(&w->sched.link, &list);
2171 rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
2175 static void execlists_unhold(struct intel_engine_cs *engine,
2176 struct i915_request *rq)
2178 spin_lock_irq(&engine->sched_engine->lock);
2181 * Move this request back to the priority queue, and all of its
2182 * children and grandchildren that were suspended along with it.
2184 __execlists_unhold(rq);
2186 if (rq_prio(rq) > engine->sched_engine->queue_priority_hint) {
2187 engine->sched_engine->queue_priority_hint = rq_prio(rq);
2188 tasklet_hi_schedule(&engine->sched_engine->tasklet);
2191 spin_unlock_irq(&engine->sched_engine->lock);
2194 struct execlists_capture {
2195 struct work_struct work;
2196 struct i915_request *rq;
2197 struct i915_gpu_coredump *error;
2200 static void execlists_capture_work(struct work_struct *work)
2202 struct execlists_capture *cap = container_of(work, typeof(*cap), work);
2203 const gfp_t gfp = __GFP_KSWAPD_RECLAIM | __GFP_RETRY_MAYFAIL |
2205 struct intel_engine_cs *engine = cap->rq->engine;
2206 struct intel_gt_coredump *gt = cap->error->gt;
2207 struct intel_engine_capture_vma *vma;
2209 /* Compress all the objects attached to the request, slow! */
2210 vma = intel_engine_coredump_add_request(gt->engine, cap->rq, gfp);
2212 struct i915_vma_compress *compress =
2213 i915_vma_capture_prepare(gt);
2215 intel_engine_coredump_add_vma(gt->engine, vma, compress);
2216 i915_vma_capture_finish(gt, compress);
2219 gt->simulated = gt->engine->simulated;
2220 cap->error->simulated = gt->simulated;
2222 /* Publish the error state, and announce it to the world */
2223 i915_error_state_store(cap->error);
2224 i915_gpu_coredump_put(cap->error);
2226 /* Return this request and all that depend upon it for signaling */
2227 execlists_unhold(engine, cap->rq);
2228 i915_request_put(cap->rq);
2233 static struct execlists_capture *capture_regs(struct intel_engine_cs *engine)
2235 const gfp_t gfp = GFP_ATOMIC | __GFP_NOWARN;
2236 struct execlists_capture *cap;
2238 cap = kmalloc(sizeof(*cap), gfp);
2242 cap->error = i915_gpu_coredump_alloc(engine->i915, gfp);
2246 cap->error->gt = intel_gt_coredump_alloc(engine->gt, gfp, CORE_DUMP_FLAG_NONE);
2247 if (!cap->error->gt)
2250 cap->error->gt->engine = intel_engine_coredump_alloc(engine, gfp, CORE_DUMP_FLAG_NONE);
2251 if (!cap->error->gt->engine)
2254 cap->error->gt->engine->hung = true;
2259 kfree(cap->error->gt);
2267 static struct i915_request *
2268 active_context(struct intel_engine_cs *engine, u32 ccid)
2270 const struct intel_engine_execlists * const el = &engine->execlists;
2271 struct i915_request * const *port, *rq;
2274 * Use the most recent result from process_csb(), but just in case
2275 * we trigger an error (via interrupt) before the first CS event has
2276 * been written, peek at the next submission.
2279 for (port = el->active; (rq = *port); port++) {
2280 if (rq->context->lrc.ccid == ccid) {
2281 ENGINE_TRACE(engine,
2282 "ccid:%x found at active:%zd\n",
2283 ccid, port - el->active);
2288 for (port = el->pending; (rq = *port); port++) {
2289 if (rq->context->lrc.ccid == ccid) {
2290 ENGINE_TRACE(engine,
2291 "ccid:%x found at pending:%zd\n",
2292 ccid, port - el->pending);
2297 ENGINE_TRACE(engine, "ccid:%x not found\n", ccid);
2301 static u32 active_ccid(struct intel_engine_cs *engine)
2303 return ENGINE_READ_FW(engine, RING_EXECLIST_STATUS_HI);
2306 static void execlists_capture(struct intel_engine_cs *engine)
2308 struct execlists_capture *cap;
2310 if (!IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR))
2314 * We need to _quickly_ capture the engine state before we reset.
2315 * We are inside an atomic section (softirq) here and we are delaying
2316 * the forced preemption event.
2318 cap = capture_regs(engine);
2322 spin_lock_irq(&engine->sched_engine->lock);
2323 cap->rq = active_context(engine, active_ccid(engine));
2325 cap->rq = active_request(cap->rq->context->timeline, cap->rq);
2326 cap->rq = i915_request_get_rcu(cap->rq);
2328 spin_unlock_irq(&engine->sched_engine->lock);
2333 * Remove the request from the execlists queue, and take ownership
2334 * of the request. We pass it to our worker who will _slowly_ compress
2335 * all the pages the _user_ requested for debugging their batch, after
2336 * which we return it to the queue for signaling.
2338 * By removing them from the execlists queue, we also remove the
2339 * requests from being processed by __unwind_incomplete_requests()
2340 * during the intel_engine_reset(), and so they will *not* be replayed
2343 * Note that because we have not yet reset the engine at this point,
2344 * it is possible for the request that we have identified as being
2345 * guilty, did in fact complete and we will then hit an arbitration
2346 * point allowing the outstanding preemption to succeed. The likelihood
2347 * of that is very low (as capturing of the engine registers should be
2348 * fast enough to run inside an irq-off atomic section!), so we will
2349 * simply hold that request accountable for being non-preemptible
2350 * long enough to force the reset.
2352 if (!execlists_hold(engine, cap->rq))
2355 INIT_WORK(&cap->work, execlists_capture_work);
2356 schedule_work(&cap->work);
2360 i915_request_put(cap->rq);
2362 i915_gpu_coredump_put(cap->error);
2366 static void execlists_reset(struct intel_engine_cs *engine, const char *msg)
2368 const unsigned int bit = I915_RESET_ENGINE + engine->id;
2369 unsigned long *lock = &engine->gt->reset.flags;
2371 if (!intel_has_reset_engine(engine->gt))
2374 if (test_and_set_bit(bit, lock))
2377 ENGINE_TRACE(engine, "reset for %s\n", msg);
2379 /* Mark this tasklet as disabled to avoid waiting for it to complete */
2380 tasklet_disable_nosync(&engine->sched_engine->tasklet);
2382 ring_set_paused(engine, 1); /* Freeze the current request in place */
2383 execlists_capture(engine);
2384 intel_engine_reset(engine, msg);
2386 tasklet_enable(&engine->sched_engine->tasklet);
2387 clear_and_wake_up_bit(bit, lock);
2390 static bool preempt_timeout(const struct intel_engine_cs *const engine)
2392 const struct timer_list *t = &engine->execlists.preempt;
2394 if (!CONFIG_DRM_I915_PREEMPT_TIMEOUT)
2397 if (!timer_expired(t))
2400 return engine->execlists.pending[0];
2404 * Check the unread Context Status Buffers and manage the submission of new
2405 * contexts to the ELSP accordingly.
2407 static void execlists_submission_tasklet(struct tasklet_struct *t)
2409 struct i915_sched_engine *sched_engine =
2410 from_tasklet(sched_engine, t, tasklet);
2411 struct intel_engine_cs * const engine = sched_engine->private_data;
2412 struct i915_request *post[2 * EXECLIST_MAX_PORTS];
2413 struct i915_request **inactive;
2416 inactive = process_csb(engine, post);
2417 GEM_BUG_ON(inactive - post > ARRAY_SIZE(post));
2419 if (unlikely(preempt_timeout(engine))) {
2420 cancel_timer(&engine->execlists.preempt);
2421 engine->execlists.error_interrupt |= ERROR_PREEMPT;
2424 if (unlikely(READ_ONCE(engine->execlists.error_interrupt))) {
2427 /* Generate the error message in priority wrt to the user! */
2428 if (engine->execlists.error_interrupt & GENMASK(15, 0))
2429 msg = "CS error"; /* thrown by a user payload */
2430 else if (engine->execlists.error_interrupt & ERROR_CSB)
2431 msg = "invalid CSB event";
2432 else if (engine->execlists.error_interrupt & ERROR_PREEMPT)
2433 msg = "preemption time out";
2435 msg = "internal error";
2437 engine->execlists.error_interrupt = 0;
2438 execlists_reset(engine, msg);
2441 if (!engine->execlists.pending[0]) {
2442 execlists_dequeue_irq(engine);
2443 start_timeslice(engine);
2446 post_process_csb(post, inactive);
2450 static void execlists_irq_handler(struct intel_engine_cs *engine, u16 iir)
2452 bool tasklet = false;
2454 if (unlikely(iir & GT_CS_MASTER_ERROR_INTERRUPT)) {
2457 /* Upper 16b are the enabling mask, rsvd for internal errors */
2458 eir = ENGINE_READ(engine, RING_EIR) & GENMASK(15, 0);
2459 ENGINE_TRACE(engine, "CS error: %x\n", eir);
2461 /* Disable the error interrupt until after the reset */
2463 ENGINE_WRITE(engine, RING_EMR, ~0u);
2464 ENGINE_WRITE(engine, RING_EIR, eir);
2465 WRITE_ONCE(engine->execlists.error_interrupt, eir);
2470 if (iir & GT_WAIT_SEMAPHORE_INTERRUPT) {
2471 WRITE_ONCE(engine->execlists.yield,
2472 ENGINE_READ_FW(engine, RING_EXECLIST_STATUS_HI));
2473 ENGINE_TRACE(engine, "semaphore yield: %08x\n",
2474 engine->execlists.yield);
2475 if (del_timer(&engine->execlists.timer))
2479 if (iir & GT_CONTEXT_SWITCH_INTERRUPT)
2482 if (iir & GT_RENDER_USER_INTERRUPT)
2483 intel_engine_signal_breadcrumbs(engine);
2486 tasklet_hi_schedule(&engine->sched_engine->tasklet);
2489 static void __execlists_kick(struct intel_engine_execlists *execlists)
2491 struct intel_engine_cs *engine =
2492 container_of(execlists, typeof(*engine), execlists);
2494 /* Kick the tasklet for some interrupt coalescing and reset handling */
2495 tasklet_hi_schedule(&engine->sched_engine->tasklet);
2498 #define execlists_kick(t, member) \
2499 __execlists_kick(container_of(t, struct intel_engine_execlists, member))
2501 static void execlists_timeslice(struct timer_list *timer)
2503 execlists_kick(timer, timer);
2506 static void execlists_preempt(struct timer_list *timer)
2508 execlists_kick(timer, preempt);
2511 static void queue_request(struct intel_engine_cs *engine,
2512 struct i915_request *rq)
2514 GEM_BUG_ON(!list_empty(&rq->sched.link));
2515 list_add_tail(&rq->sched.link,
2516 i915_sched_lookup_priolist(engine->sched_engine,
2518 set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
2521 static bool submit_queue(struct intel_engine_cs *engine,
2522 const struct i915_request *rq)
2524 struct i915_sched_engine *sched_engine = engine->sched_engine;
2526 if (rq_prio(rq) <= sched_engine->queue_priority_hint)
2529 sched_engine->queue_priority_hint = rq_prio(rq);
2533 static bool ancestor_on_hold(const struct intel_engine_cs *engine,
2534 const struct i915_request *rq)
2536 GEM_BUG_ON(i915_request_on_hold(rq));
2537 return !list_empty(&engine->sched_engine->hold) && hold_request(rq);
2540 static void execlists_submit_request(struct i915_request *request)
2542 struct intel_engine_cs *engine = request->engine;
2543 unsigned long flags;
2545 /* Will be called from irq-context when using foreign fences. */
2546 spin_lock_irqsave(&engine->sched_engine->lock, flags);
2548 if (unlikely(ancestor_on_hold(engine, request))) {
2549 RQ_TRACE(request, "ancestor on hold\n");
2550 list_add_tail(&request->sched.link,
2551 &engine->sched_engine->hold);
2552 i915_request_set_hold(request);
2554 queue_request(engine, request);
2556 GEM_BUG_ON(i915_sched_engine_is_empty(engine->sched_engine));
2557 GEM_BUG_ON(list_empty(&request->sched.link));
2559 if (submit_queue(engine, request))
2560 __execlists_kick(&engine->execlists);
2563 spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
2567 __execlists_context_pre_pin(struct intel_context *ce,
2568 struct intel_engine_cs *engine,
2569 struct i915_gem_ww_ctx *ww, void **vaddr)
2573 err = lrc_pre_pin(ce, engine, ww, vaddr);
2577 if (!__test_and_set_bit(CONTEXT_INIT_BIT, &ce->flags)) {
2578 lrc_init_state(ce, engine, *vaddr);
2580 __i915_gem_object_flush_map(ce->state->obj, 0, engine->context_size);
2586 static int execlists_context_pre_pin(struct intel_context *ce,
2587 struct i915_gem_ww_ctx *ww,
2590 return __execlists_context_pre_pin(ce, ce->engine, ww, vaddr);
2593 static int execlists_context_pin(struct intel_context *ce, void *vaddr)
2595 return lrc_pin(ce, ce->engine, vaddr);
2598 static int execlists_context_alloc(struct intel_context *ce)
2600 return lrc_alloc(ce, ce->engine);
2603 static void execlists_context_cancel_request(struct intel_context *ce,
2604 struct i915_request *rq)
2606 struct intel_engine_cs *engine = NULL;
2608 i915_request_active_engine(rq, &engine);
2610 if (engine && intel_engine_pulse(engine))
2611 intel_gt_handle_error(engine->gt, engine->mask, 0,
2612 "request cancellation by %s",
2616 static struct intel_context *
2617 execlists_create_parallel(struct intel_engine_cs **engines,
2618 unsigned int num_siblings,
2621 struct intel_context *parent = NULL, *ce, *err;
2624 GEM_BUG_ON(num_siblings != 1);
2626 for (i = 0; i < width; ++i) {
2627 ce = intel_context_create(engines[i]);
2636 intel_context_bind_parent_child(parent, ce);
2639 parent->parallel.fence_context = dma_fence_context_alloc(1);
2641 intel_context_set_nopreempt(parent);
2642 for_each_child(parent, ce)
2643 intel_context_set_nopreempt(ce);
2649 intel_context_put(parent);
2653 static const struct intel_context_ops execlists_context_ops = {
2654 .flags = COPS_HAS_INFLIGHT | COPS_RUNTIME_CYCLES,
2656 .alloc = execlists_context_alloc,
2658 .cancel_request = execlists_context_cancel_request,
2660 .pre_pin = execlists_context_pre_pin,
2661 .pin = execlists_context_pin,
2663 .post_unpin = lrc_post_unpin,
2665 .enter = intel_context_enter_engine,
2666 .exit = intel_context_exit_engine,
2669 .destroy = lrc_destroy,
2671 .create_parallel = execlists_create_parallel,
2672 .create_virtual = execlists_create_virtual,
2675 static int emit_pdps(struct i915_request *rq)
2677 const struct intel_engine_cs * const engine = rq->engine;
2678 struct i915_ppgtt * const ppgtt = i915_vm_to_ppgtt(rq->context->vm);
2682 GEM_BUG_ON(intel_vgpu_active(rq->engine->i915));
2685 * Beware ye of the dragons, this sequence is magic!
2687 * Small changes to this sequence can cause anything from
2688 * GPU hangs to forcewake errors and machine lockups!
2691 cs = intel_ring_begin(rq, 2);
2695 *cs++ = MI_ARB_ON_OFF | MI_ARB_DISABLE;
2697 intel_ring_advance(rq, cs);
2699 /* Flush any residual operations from the context load */
2700 err = engine->emit_flush(rq, EMIT_FLUSH);
2704 /* Magic required to prevent forcewake errors! */
2705 err = engine->emit_flush(rq, EMIT_INVALIDATE);
2709 cs = intel_ring_begin(rq, 4 * GEN8_3LVL_PDPES + 2);
2713 /* Ensure the LRI have landed before we invalidate & continue */
2714 *cs++ = MI_LOAD_REGISTER_IMM(2 * GEN8_3LVL_PDPES) | MI_LRI_FORCE_POSTED;
2715 for (i = GEN8_3LVL_PDPES; i--; ) {
2716 const dma_addr_t pd_daddr = i915_page_dir_dma_addr(ppgtt, i);
2717 u32 base = engine->mmio_base;
2719 *cs++ = i915_mmio_reg_offset(GEN8_RING_PDP_UDW(base, i));
2720 *cs++ = upper_32_bits(pd_daddr);
2721 *cs++ = i915_mmio_reg_offset(GEN8_RING_PDP_LDW(base, i));
2722 *cs++ = lower_32_bits(pd_daddr);
2724 *cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
2725 intel_ring_advance(rq, cs);
2727 intel_ring_advance(rq, cs);
2732 static int execlists_request_alloc(struct i915_request *request)
2736 GEM_BUG_ON(!intel_context_is_pinned(request->context));
2739 * Flush enough space to reduce the likelihood of waiting after
2740 * we start building the request - in which case we will just
2741 * have to repeat work.
2743 request->reserved_space += EXECLISTS_REQUEST_SIZE;
2746 * Note that after this point, we have committed to using
2747 * this request as it is being used to both track the
2748 * state of engine initialisation and liveness of the
2749 * golden renderstate above. Think twice before you try
2750 * to cancel/unwind this request now.
2753 if (!i915_vm_is_4lvl(request->context->vm)) {
2754 ret = emit_pdps(request);
2759 /* Unconditionally invalidate GPU caches and TLBs. */
2760 ret = request->engine->emit_flush(request, EMIT_INVALIDATE);
2764 request->reserved_space -= EXECLISTS_REQUEST_SIZE;
2768 static void reset_csb_pointers(struct intel_engine_cs *engine)
2770 struct intel_engine_execlists * const execlists = &engine->execlists;
2771 const unsigned int reset_value = execlists->csb_size - 1;
2773 ring_set_paused(engine, 0);
2776 * Sometimes Icelake forgets to reset its pointers on a GPU reset.
2777 * Bludgeon them with a mmio update to be sure.
2779 ENGINE_WRITE(engine, RING_CONTEXT_STATUS_PTR,
2780 0xffff << 16 | reset_value << 8 | reset_value);
2781 ENGINE_POSTING_READ(engine, RING_CONTEXT_STATUS_PTR);
2784 * After a reset, the HW starts writing into CSB entry [0]. We
2785 * therefore have to set our HEAD pointer back one entry so that
2786 * the *first* entry we check is entry 0. To complicate this further,
2787 * as we don't wait for the first interrupt after reset, we have to
2788 * fake the HW write to point back to the last entry so that our
2789 * inline comparison of our cached head position against the last HW
2790 * write works even before the first interrupt.
2792 execlists->csb_head = reset_value;
2793 WRITE_ONCE(*execlists->csb_write, reset_value);
2794 wmb(); /* Make sure this is visible to HW (paranoia?) */
2796 /* Check that the GPU does indeed update the CSB entries! */
2797 memset(execlists->csb_status, -1, (reset_value + 1) * sizeof(u64));
2798 drm_clflush_virt_range(execlists->csb_status,
2799 execlists->csb_size *
2800 sizeof(execlists->csb_status));
2802 /* Once more for luck and our trusty paranoia */
2803 ENGINE_WRITE(engine, RING_CONTEXT_STATUS_PTR,
2804 0xffff << 16 | reset_value << 8 | reset_value);
2805 ENGINE_POSTING_READ(engine, RING_CONTEXT_STATUS_PTR);
2807 GEM_BUG_ON(READ_ONCE(*execlists->csb_write) != reset_value);
2810 static void sanitize_hwsp(struct intel_engine_cs *engine)
2812 struct intel_timeline *tl;
2814 list_for_each_entry(tl, &engine->status_page.timelines, engine_link)
2815 intel_timeline_reset_seqno(tl);
2818 static void execlists_sanitize(struct intel_engine_cs *engine)
2820 GEM_BUG_ON(execlists_active(&engine->execlists));
2823 * Poison residual state on resume, in case the suspend didn't!
2825 * We have to assume that across suspend/resume (or other loss
2826 * of control) that the contents of our pinned buffers has been
2827 * lost, replaced by garbage. Since this doesn't always happen,
2828 * let's poison such state so that we more quickly spot when
2829 * we falsely assume it has been preserved.
2831 if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
2832 memset(engine->status_page.addr, POISON_INUSE, PAGE_SIZE);
2834 reset_csb_pointers(engine);
2837 * The kernel_context HWSP is stored in the status_page. As above,
2838 * that may be lost on resume/initialisation, and so we need to
2839 * reset the value in the HWSP.
2841 sanitize_hwsp(engine);
2843 /* And scrub the dirty cachelines for the HWSP */
2844 drm_clflush_virt_range(engine->status_page.addr, PAGE_SIZE);
2846 intel_engine_reset_pinned_contexts(engine);
2849 static void enable_error_interrupt(struct intel_engine_cs *engine)
2853 engine->execlists.error_interrupt = 0;
2854 ENGINE_WRITE(engine, RING_EMR, ~0u);
2855 ENGINE_WRITE(engine, RING_EIR, ~0u); /* clear all existing errors */
2857 status = ENGINE_READ(engine, RING_ESR);
2858 if (unlikely(status)) {
2859 drm_err(&engine->i915->drm,
2860 "engine '%s' resumed still in error: %08x\n",
2861 engine->name, status);
2862 __intel_gt_reset(engine->gt, engine->mask);
2866 * On current gen8+, we have 2 signals to play with
2868 * - I915_ERROR_INSTUCTION (bit 0)
2870 * Generate an error if the command parser encounters an invalid
2873 * This is a fatal error.
2877 * Generate an error on privilege violation (where the CP replaces
2878 * the instruction with a no-op). This also fires for writes into
2879 * read-only scratch pages.
2881 * This is a non-fatal error, parsing continues.
2883 * * there are a few others defined for odd HW that we do not use
2885 * Since CP_PRIV fires for cases where we have chosen to ignore the
2886 * error (as the HW is validating and suppressing the mistakes), we
2887 * only unmask the instruction error bit.
2889 ENGINE_WRITE(engine, RING_EMR, ~I915_ERROR_INSTRUCTION);
2892 static void enable_execlists(struct intel_engine_cs *engine)
2896 assert_forcewakes_active(engine->uncore, FORCEWAKE_ALL);
2898 intel_engine_set_hwsp_writemask(engine, ~0u); /* HWSTAM */
2900 if (GRAPHICS_VER(engine->i915) >= 11)
2901 mode = _MASKED_BIT_ENABLE(GEN11_GFX_DISABLE_LEGACY_MODE);
2903 mode = _MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE);
2904 ENGINE_WRITE_FW(engine, RING_MODE_GEN7, mode);
2906 ENGINE_WRITE_FW(engine, RING_MI_MODE, _MASKED_BIT_DISABLE(STOP_RING));
2908 ENGINE_WRITE_FW(engine,
2910 i915_ggtt_offset(engine->status_page.vma));
2911 ENGINE_POSTING_READ(engine, RING_HWS_PGA);
2913 enable_error_interrupt(engine);
2916 static int execlists_resume(struct intel_engine_cs *engine)
2918 intel_mocs_init_engine(engine);
2919 intel_breadcrumbs_reset(engine->breadcrumbs);
2921 enable_execlists(engine);
2923 if (engine->flags & I915_ENGINE_FIRST_RENDER_COMPUTE)
2924 xehp_enable_ccs_engines(engine);
2929 static void execlists_reset_prepare(struct intel_engine_cs *engine)
2931 ENGINE_TRACE(engine, "depth<-%d\n",
2932 atomic_read(&engine->sched_engine->tasklet.count));
2935 * Prevent request submission to the hardware until we have
2936 * completed the reset in i915_gem_reset_finish(). If a request
2937 * is completed by one engine, it may then queue a request
2938 * to a second via its execlists->tasklet *just* as we are
2939 * calling engine->resume() and also writing the ELSP.
2940 * Turning off the execlists->tasklet until the reset is over
2941 * prevents the race.
2943 __tasklet_disable_sync_once(&engine->sched_engine->tasklet);
2944 GEM_BUG_ON(!reset_in_progress(engine));
2947 * We stop engines, otherwise we might get failed reset and a
2948 * dead gpu (on elk). Also as modern gpu as kbl can suffer
2949 * from system hang if batchbuffer is progressing when
2950 * the reset is issued, regardless of READY_TO_RESET ack.
2951 * Thus assume it is best to stop engines on all gens
2952 * where we have a gpu reset.
2954 * WaKBLVECSSemaphoreWaitPoll:kbl (on ALL_ENGINES)
2956 * FIXME: Wa for more modern gens needs to be validated
2958 ring_set_paused(engine, 1);
2959 intel_engine_stop_cs(engine);
2961 engine->execlists.reset_ccid = active_ccid(engine);
2964 static struct i915_request **
2965 reset_csb(struct intel_engine_cs *engine, struct i915_request **inactive)
2967 struct intel_engine_execlists * const execlists = &engine->execlists;
2969 drm_clflush_virt_range(execlists->csb_write,
2970 sizeof(execlists->csb_write[0]));
2972 inactive = process_csb(engine, inactive); /* drain preemption events */
2974 /* Following the reset, we need to reload the CSB read/write pointers */
2975 reset_csb_pointers(engine);
2981 execlists_reset_active(struct intel_engine_cs *engine, bool stalled)
2983 struct intel_context *ce;
2984 struct i915_request *rq;
2988 * Save the currently executing context, even if we completed
2989 * its request, it was still running at the time of the
2990 * reset and will have been clobbered.
2992 rq = active_context(engine, engine->execlists.reset_ccid);
2997 GEM_BUG_ON(!i915_vma_is_pinned(ce->state));
2999 if (__i915_request_is_complete(rq)) {
3000 /* Idle context; tidy up the ring so we can restart afresh */
3001 head = intel_ring_wrap(ce->ring, rq->tail);
3005 /* We still have requests in-flight; the engine should be active */
3006 GEM_BUG_ON(!intel_engine_pm_is_awake(engine));
3008 /* Context has requests still in-flight; it should not be idle! */
3009 GEM_BUG_ON(i915_active_is_idle(&ce->active));
3011 rq = active_request(ce->timeline, rq);
3012 head = intel_ring_wrap(ce->ring, rq->head);
3013 GEM_BUG_ON(head == ce->ring->tail);
3016 * If this request hasn't started yet, e.g. it is waiting on a
3017 * semaphore, we need to avoid skipping the request or else we
3018 * break the signaling chain. However, if the context is corrupt
3019 * the request will not restart and we will be stuck with a wedged
3020 * device. It is quite often the case that if we issue a reset
3021 * while the GPU is loading the context image, that the context
3022 * image becomes corrupt.
3024 * Otherwise, if we have not started yet, the request should replay
3025 * perfectly and we do not need to flag the result as being erroneous.
3027 if (!__i915_request_has_started(rq))
3031 * If the request was innocent, we leave the request in the ELSP
3032 * and will try to replay it on restarting. The context image may
3033 * have been corrupted by the reset, in which case we may have
3034 * to service a new GPU hang, but more likely we can continue on
3037 * If the request was guilty, we presume the context is corrupt
3038 * and have to at least restore the RING register in the context
3039 * image back to the expected values to skip over the guilty request.
3041 __i915_request_reset(rq, stalled);
3044 * We want a simple context + ring to execute the breadcrumb update.
3045 * We cannot rely on the context being intact across the GPU hang,
3046 * so clear it and rebuild just what we need for the breadcrumb.
3047 * All pending requests for this context will be zapped, and any
3048 * future request will be after userspace has had the opportunity
3049 * to recreate its own state.
3052 ENGINE_TRACE(engine, "replay {head:%04x, tail:%04x}\n",
3053 head, ce->ring->tail);
3054 lrc_reset_regs(ce, engine);
3055 ce->lrc.lrca = lrc_update_regs(ce, engine, head);
3058 static void execlists_reset_csb(struct intel_engine_cs *engine, bool stalled)
3060 struct intel_engine_execlists * const execlists = &engine->execlists;
3061 struct i915_request *post[2 * EXECLIST_MAX_PORTS];
3062 struct i915_request **inactive;
3065 inactive = reset_csb(engine, post);
3067 execlists_reset_active(engine, true);
3069 inactive = cancel_port_requests(execlists, inactive);
3070 post_process_csb(post, inactive);
3074 static void execlists_reset_rewind(struct intel_engine_cs *engine, bool stalled)
3076 unsigned long flags;
3078 ENGINE_TRACE(engine, "\n");
3080 /* Process the csb, find the guilty context and throw away */
3081 execlists_reset_csb(engine, stalled);
3083 /* Push back any incomplete requests for replay after the reset. */
3085 spin_lock_irqsave(&engine->sched_engine->lock, flags);
3086 __unwind_incomplete_requests(engine);
3087 spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
3091 static void nop_submission_tasklet(struct tasklet_struct *t)
3093 struct i915_sched_engine *sched_engine =
3094 from_tasklet(sched_engine, t, tasklet);
3095 struct intel_engine_cs * const engine = sched_engine->private_data;
3097 /* The driver is wedged; don't process any more events. */
3098 WRITE_ONCE(engine->sched_engine->queue_priority_hint, INT_MIN);
3101 static void execlists_reset_cancel(struct intel_engine_cs *engine)
3103 struct intel_engine_execlists * const execlists = &engine->execlists;
3104 struct i915_sched_engine * const sched_engine = engine->sched_engine;
3105 struct i915_request *rq, *rn;
3107 unsigned long flags;
3109 ENGINE_TRACE(engine, "\n");
3112 * Before we call engine->cancel_requests(), we should have exclusive
3113 * access to the submission state. This is arranged for us by the
3114 * caller disabling the interrupt generation, the tasklet and other
3115 * threads that may then access the same state, giving us a free hand
3116 * to reset state. However, we still need to let lockdep be aware that
3117 * we know this state may be accessed in hardirq context, so we
3118 * disable the irq around this manipulation and we want to keep
3119 * the spinlock focused on its duties and not accidentally conflate
3120 * coverage to the submission's irq state. (Similarly, although we
3121 * shouldn't need to disable irq around the manipulation of the
3122 * submission's irq state, we also wish to remind ourselves that
3125 execlists_reset_csb(engine, true);
3128 spin_lock_irqsave(&engine->sched_engine->lock, flags);
3130 /* Mark all executing requests as skipped. */
3131 list_for_each_entry(rq, &engine->sched_engine->requests, sched.link)
3132 i915_request_put(i915_request_mark_eio(rq));
3133 intel_engine_signal_breadcrumbs(engine);
3135 /* Flush the queued requests to the timeline list (for retiring). */
3136 while ((rb = rb_first_cached(&sched_engine->queue))) {
3137 struct i915_priolist *p = to_priolist(rb);
3139 priolist_for_each_request_consume(rq, rn, p) {
3140 if (i915_request_mark_eio(rq)) {
3141 __i915_request_submit(rq);
3142 i915_request_put(rq);
3146 rb_erase_cached(&p->node, &sched_engine->queue);
3147 i915_priolist_free(p);
3150 /* On-hold requests will be flushed to timeline upon their release */
3151 list_for_each_entry(rq, &sched_engine->hold, sched.link)
3152 i915_request_put(i915_request_mark_eio(rq));
3154 /* Cancel all attached virtual engines */
3155 while ((rb = rb_first_cached(&execlists->virtual))) {
3156 struct virtual_engine *ve =
3157 rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
3159 rb_erase_cached(rb, &execlists->virtual);
3162 spin_lock(&ve->base.sched_engine->lock);
3163 rq = fetch_and_zero(&ve->request);
3165 if (i915_request_mark_eio(rq)) {
3166 rq->engine = engine;
3167 __i915_request_submit(rq);
3168 i915_request_put(rq);
3170 i915_request_put(rq);
3172 ve->base.sched_engine->queue_priority_hint = INT_MIN;
3174 spin_unlock(&ve->base.sched_engine->lock);
3177 /* Remaining _unready_ requests will be nop'ed when submitted */
3179 sched_engine->queue_priority_hint = INT_MIN;
3180 sched_engine->queue = RB_ROOT_CACHED;
3182 GEM_BUG_ON(__tasklet_is_enabled(&engine->sched_engine->tasklet));
3183 engine->sched_engine->tasklet.callback = nop_submission_tasklet;
3185 spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
3189 static void execlists_reset_finish(struct intel_engine_cs *engine)
3191 struct intel_engine_execlists * const execlists = &engine->execlists;
3194 * After a GPU reset, we may have requests to replay. Do so now while
3195 * we still have the forcewake to be sure that the GPU is not allowed
3196 * to sleep before we restart and reload a context.
3198 * If the GPU reset fails, the engine may still be alive with requests
3199 * inflight. We expect those to complete, or for the device to be
3200 * reset as the next level of recovery, and as a final resort we
3201 * will declare the device wedged.
3203 GEM_BUG_ON(!reset_in_progress(engine));
3205 /* And kick in case we missed a new request submission. */
3206 if (__tasklet_enable(&engine->sched_engine->tasklet))
3207 __execlists_kick(execlists);
3209 ENGINE_TRACE(engine, "depth->%d\n",
3210 atomic_read(&engine->sched_engine->tasklet.count));
3213 static void gen8_logical_ring_enable_irq(struct intel_engine_cs *engine)
3215 ENGINE_WRITE(engine, RING_IMR,
3216 ~(engine->irq_enable_mask | engine->irq_keep_mask));
3217 ENGINE_POSTING_READ(engine, RING_IMR);
3220 static void gen8_logical_ring_disable_irq(struct intel_engine_cs *engine)
3222 ENGINE_WRITE(engine, RING_IMR, ~engine->irq_keep_mask);
3225 static void execlists_park(struct intel_engine_cs *engine)
3227 cancel_timer(&engine->execlists.timer);
3228 cancel_timer(&engine->execlists.preempt);
3231 static void add_to_engine(struct i915_request *rq)
3233 lockdep_assert_held(&rq->engine->sched_engine->lock);
3234 list_move_tail(&rq->sched.link, &rq->engine->sched_engine->requests);
3237 static void remove_from_engine(struct i915_request *rq)
3239 struct intel_engine_cs *engine, *locked;
3242 * Virtual engines complicate acquiring the engine timeline lock,
3243 * as their rq->engine pointer is not stable until under that
3244 * engine lock. The simple ploy we use is to take the lock then
3245 * check that the rq still belongs to the newly locked engine.
3247 locked = READ_ONCE(rq->engine);
3248 spin_lock_irq(&locked->sched_engine->lock);
3249 while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
3250 spin_unlock(&locked->sched_engine->lock);
3251 spin_lock(&engine->sched_engine->lock);
3254 list_del_init(&rq->sched.link);
3256 clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
3257 clear_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags);
3259 /* Prevent further __await_execution() registering a cb, then flush */
3260 set_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags);
3262 spin_unlock_irq(&locked->sched_engine->lock);
3264 i915_request_notify_execute_cb_imm(rq);
3267 static bool can_preempt(struct intel_engine_cs *engine)
3269 if (GRAPHICS_VER(engine->i915) > 8)
3272 /* GPGPU on bdw requires extra w/a; not implemented */
3273 return engine->class != RENDER_CLASS;
3276 static void kick_execlists(const struct i915_request *rq, int prio)
3278 struct intel_engine_cs *engine = rq->engine;
3279 struct i915_sched_engine *sched_engine = engine->sched_engine;
3280 const struct i915_request *inflight;
3283 * We only need to kick the tasklet once for the high priority
3284 * new context we add into the queue.
3286 if (prio <= sched_engine->queue_priority_hint)
3291 /* Nothing currently active? We're overdue for a submission! */
3292 inflight = execlists_active(&engine->execlists);
3297 * If we are already the currently executing context, don't
3298 * bother evaluating if we should preempt ourselves.
3300 if (inflight->context == rq->context)
3303 ENGINE_TRACE(engine,
3304 "bumping queue-priority-hint:%d for rq:%llx:%lld, inflight:%llx:%lld prio %d\n",
3306 rq->fence.context, rq->fence.seqno,
3307 inflight->fence.context, inflight->fence.seqno,
3308 inflight->sched.attr.priority);
3310 sched_engine->queue_priority_hint = prio;
3313 * Allow preemption of low -> normal -> high, but we do
3314 * not allow low priority tasks to preempt other low priority
3315 * tasks under the impression that latency for low priority
3316 * tasks does not matter (as much as background throughput),
3319 if (prio >= max(I915_PRIORITY_NORMAL, rq_prio(inflight)))
3320 tasklet_hi_schedule(&sched_engine->tasklet);
3326 static void execlists_set_default_submission(struct intel_engine_cs *engine)
3328 engine->submit_request = execlists_submit_request;
3329 engine->sched_engine->schedule = i915_schedule;
3330 engine->sched_engine->kick_backend = kick_execlists;
3331 engine->sched_engine->tasklet.callback = execlists_submission_tasklet;
3334 static void execlists_shutdown(struct intel_engine_cs *engine)
3336 /* Synchronise with residual timers and any softirq they raise */
3337 del_timer_sync(&engine->execlists.timer);
3338 del_timer_sync(&engine->execlists.preempt);
3339 tasklet_kill(&engine->sched_engine->tasklet);
3342 static void execlists_release(struct intel_engine_cs *engine)
3344 engine->sanitize = NULL; /* no longer in control, nothing to sanitize */
3346 execlists_shutdown(engine);
3348 intel_engine_cleanup_common(engine);
3349 lrc_fini_wa_ctx(engine);
3352 static ktime_t __execlists_engine_busyness(struct intel_engine_cs *engine,
3355 struct intel_engine_execlists_stats *stats = &engine->stats.execlists;
3356 ktime_t total = stats->total;
3359 * If the engine is executing something at the moment
3360 * add it to the total.
3363 if (READ_ONCE(stats->active))
3364 total = ktime_add(total, ktime_sub(*now, stats->start));
3369 static ktime_t execlists_engine_busyness(struct intel_engine_cs *engine,
3372 struct intel_engine_execlists_stats *stats = &engine->stats.execlists;
3377 seq = read_seqcount_begin(&stats->lock);
3378 total = __execlists_engine_busyness(engine, now);
3379 } while (read_seqcount_retry(&stats->lock, seq));
3385 logical_ring_default_vfuncs(struct intel_engine_cs *engine)
3387 /* Default vfuncs which can be overridden by each engine. */
3389 engine->resume = execlists_resume;
3391 engine->cops = &execlists_context_ops;
3392 engine->request_alloc = execlists_request_alloc;
3393 engine->add_active_request = add_to_engine;
3394 engine->remove_active_request = remove_from_engine;
3396 engine->reset.prepare = execlists_reset_prepare;
3397 engine->reset.rewind = execlists_reset_rewind;
3398 engine->reset.cancel = execlists_reset_cancel;
3399 engine->reset.finish = execlists_reset_finish;
3401 engine->park = execlists_park;
3402 engine->unpark = NULL;
3404 engine->emit_flush = gen8_emit_flush_xcs;
3405 engine->emit_init_breadcrumb = gen8_emit_init_breadcrumb;
3406 engine->emit_fini_breadcrumb = gen8_emit_fini_breadcrumb_xcs;
3407 if (GRAPHICS_VER(engine->i915) >= 12) {
3408 engine->emit_fini_breadcrumb = gen12_emit_fini_breadcrumb_xcs;
3409 engine->emit_flush = gen12_emit_flush_xcs;
3411 engine->set_default_submission = execlists_set_default_submission;
3413 if (GRAPHICS_VER(engine->i915) < 11) {
3414 engine->irq_enable = gen8_logical_ring_enable_irq;
3415 engine->irq_disable = gen8_logical_ring_disable_irq;
3418 * TODO: On Gen11 interrupt masks need to be clear
3419 * to allow C6 entry. Keep interrupts enabled at
3420 * and take the hit of generating extra interrupts
3421 * until a more refined solution exists.
3424 intel_engine_set_irq_handler(engine, execlists_irq_handler);
3426 engine->flags |= I915_ENGINE_SUPPORTS_STATS;
3427 if (!intel_vgpu_active(engine->i915)) {
3428 engine->flags |= I915_ENGINE_HAS_SEMAPHORES;
3429 if (can_preempt(engine)) {
3430 engine->flags |= I915_ENGINE_HAS_PREEMPTION;
3431 if (CONFIG_DRM_I915_TIMESLICE_DURATION)
3432 engine->flags |= I915_ENGINE_HAS_TIMESLICES;
3436 if (GRAPHICS_VER_FULL(engine->i915) >= IP_VER(12, 50)) {
3437 if (intel_engine_has_preemption(engine))
3438 engine->emit_bb_start = gen125_emit_bb_start;
3440 engine->emit_bb_start = gen125_emit_bb_start_noarb;
3442 if (intel_engine_has_preemption(engine))
3443 engine->emit_bb_start = gen8_emit_bb_start;
3445 engine->emit_bb_start = gen8_emit_bb_start_noarb;
3448 engine->busyness = execlists_engine_busyness;
3451 static void logical_ring_default_irqs(struct intel_engine_cs *engine)
3453 unsigned int shift = 0;
3455 if (GRAPHICS_VER(engine->i915) < 11) {
3456 const u8 irq_shifts[] = {
3457 [RCS0] = GEN8_RCS_IRQ_SHIFT,
3458 [BCS0] = GEN8_BCS_IRQ_SHIFT,
3459 [VCS0] = GEN8_VCS0_IRQ_SHIFT,
3460 [VCS1] = GEN8_VCS1_IRQ_SHIFT,
3461 [VECS0] = GEN8_VECS_IRQ_SHIFT,
3464 shift = irq_shifts[engine->id];
3467 engine->irq_enable_mask = GT_RENDER_USER_INTERRUPT << shift;
3468 engine->irq_keep_mask = GT_CONTEXT_SWITCH_INTERRUPT << shift;
3469 engine->irq_keep_mask |= GT_CS_MASTER_ERROR_INTERRUPT << shift;
3470 engine->irq_keep_mask |= GT_WAIT_SEMAPHORE_INTERRUPT << shift;
3473 static void rcs_submission_override(struct intel_engine_cs *engine)
3475 switch (GRAPHICS_VER(engine->i915)) {
3477 engine->emit_flush = gen12_emit_flush_rcs;
3478 engine->emit_fini_breadcrumb = gen12_emit_fini_breadcrumb_rcs;
3481 engine->emit_flush = gen11_emit_flush_rcs;
3482 engine->emit_fini_breadcrumb = gen11_emit_fini_breadcrumb_rcs;
3485 engine->emit_flush = gen8_emit_flush_rcs;
3486 engine->emit_fini_breadcrumb = gen8_emit_fini_breadcrumb_rcs;
3491 int intel_execlists_submission_setup(struct intel_engine_cs *engine)
3493 struct intel_engine_execlists * const execlists = &engine->execlists;
3494 struct drm_i915_private *i915 = engine->i915;
3495 struct intel_uncore *uncore = engine->uncore;
3496 u32 base = engine->mmio_base;
3498 tasklet_setup(&engine->sched_engine->tasklet, execlists_submission_tasklet);
3499 timer_setup(&engine->execlists.timer, execlists_timeslice, 0);
3500 timer_setup(&engine->execlists.preempt, execlists_preempt, 0);
3502 logical_ring_default_vfuncs(engine);
3503 logical_ring_default_irqs(engine);
3505 if (engine->flags & I915_ENGINE_HAS_RCS_REG_STATE)
3506 rcs_submission_override(engine);
3508 lrc_init_wa_ctx(engine);
3510 if (HAS_LOGICAL_RING_ELSQ(i915)) {
3511 execlists->submit_reg = uncore->regs +
3512 i915_mmio_reg_offset(RING_EXECLIST_SQ_CONTENTS(base));
3513 execlists->ctrl_reg = uncore->regs +
3514 i915_mmio_reg_offset(RING_EXECLIST_CONTROL(base));
3516 engine->fw_domain = intel_uncore_forcewake_for_reg(engine->uncore,
3517 RING_EXECLIST_CONTROL(engine->mmio_base),
3520 execlists->submit_reg = uncore->regs +
3521 i915_mmio_reg_offset(RING_ELSP(base));
3524 execlists->csb_status =
3525 (u64 *)&engine->status_page.addr[I915_HWS_CSB_BUF0_INDEX];
3527 execlists->csb_write =
3528 &engine->status_page.addr[INTEL_HWS_CSB_WRITE_INDEX(i915)];
3530 if (GRAPHICS_VER(i915) < 11)
3531 execlists->csb_size = GEN8_CSB_ENTRIES;
3533 execlists->csb_size = GEN11_CSB_ENTRIES;
3535 engine->context_tag = GENMASK(BITS_PER_LONG - 2, 0);
3536 if (GRAPHICS_VER(engine->i915) >= 11 &&
3537 GRAPHICS_VER_FULL(engine->i915) < IP_VER(12, 50)) {
3538 execlists->ccid |= engine->instance << (GEN11_ENGINE_INSTANCE_SHIFT - 32);
3539 execlists->ccid |= engine->class << (GEN11_ENGINE_CLASS_SHIFT - 32);
3542 /* Finally, take ownership and responsibility for cleanup! */
3543 engine->sanitize = execlists_sanitize;
3544 engine->release = execlists_release;
3549 static struct list_head *virtual_queue(struct virtual_engine *ve)
3551 return &ve->base.sched_engine->default_priolist.requests;
3554 static void rcu_virtual_context_destroy(struct work_struct *wrk)
3556 struct virtual_engine *ve =
3557 container_of(wrk, typeof(*ve), rcu.work);
3560 GEM_BUG_ON(ve->context.inflight);
3562 /* Preempt-to-busy may leave a stale request behind. */
3563 if (unlikely(ve->request)) {
3564 struct i915_request *old;
3566 spin_lock_irq(&ve->base.sched_engine->lock);
3568 old = fetch_and_zero(&ve->request);
3570 GEM_BUG_ON(!__i915_request_is_complete(old));
3571 __i915_request_submit(old);
3572 i915_request_put(old);
3575 spin_unlock_irq(&ve->base.sched_engine->lock);
3579 * Flush the tasklet in case it is still running on another core.
3581 * This needs to be done before we remove ourselves from the siblings'
3582 * rbtrees as in the case it is running in parallel, it may reinsert
3583 * the rb_node into a sibling.
3585 tasklet_kill(&ve->base.sched_engine->tasklet);
3587 /* Decouple ourselves from the siblings, no more access allowed. */
3588 for (n = 0; n < ve->num_siblings; n++) {
3589 struct intel_engine_cs *sibling = ve->siblings[n];
3590 struct rb_node *node = &ve->nodes[sibling->id].rb;
3592 if (RB_EMPTY_NODE(node))
3595 spin_lock_irq(&sibling->sched_engine->lock);
3597 /* Detachment is lazily performed in the sched_engine->tasklet */
3598 if (!RB_EMPTY_NODE(node))
3599 rb_erase_cached(node, &sibling->execlists.virtual);
3601 spin_unlock_irq(&sibling->sched_engine->lock);
3603 GEM_BUG_ON(__tasklet_is_scheduled(&ve->base.sched_engine->tasklet));
3604 GEM_BUG_ON(!list_empty(virtual_queue(ve)));
3606 lrc_fini(&ve->context);
3607 intel_context_fini(&ve->context);
3609 if (ve->base.breadcrumbs)
3610 intel_breadcrumbs_put(ve->base.breadcrumbs);
3611 if (ve->base.sched_engine)
3612 i915_sched_engine_put(ve->base.sched_engine);
3613 intel_engine_free_request_pool(&ve->base);
3618 static void virtual_context_destroy(struct kref *kref)
3620 struct virtual_engine *ve =
3621 container_of(kref, typeof(*ve), context.ref);
3623 GEM_BUG_ON(!list_empty(&ve->context.signals));
3626 * When destroying the virtual engine, we have to be aware that
3627 * it may still be in use from an hardirq/softirq context causing
3628 * the resubmission of a completed request (background completion
3629 * due to preempt-to-busy). Before we can free the engine, we need
3630 * to flush the submission code and tasklets that are still potentially
3631 * accessing the engine. Flushing the tasklets requires process context,
3632 * and since we can guard the resubmit onto the engine with an RCU read
3633 * lock, we can delegate the free of the engine to an RCU worker.
3635 INIT_RCU_WORK(&ve->rcu, rcu_virtual_context_destroy);
3636 queue_rcu_work(system_wq, &ve->rcu);
3639 static void virtual_engine_initial_hint(struct virtual_engine *ve)
3644 * Pick a random sibling on starting to help spread the load around.
3646 * New contexts are typically created with exactly the same order
3647 * of siblings, and often started in batches. Due to the way we iterate
3648 * the array of sibling when submitting requests, sibling[0] is
3649 * prioritised for dequeuing. If we make sure that sibling[0] is fairly
3650 * randomised across the system, we also help spread the load by the
3651 * first engine we inspect being different each time.
3653 * NB This does not force us to execute on this engine, it will just
3654 * typically be the first we inspect for submission.
3656 swp = prandom_u32_max(ve->num_siblings);
3658 swap(ve->siblings[swp], ve->siblings[0]);
3661 static int virtual_context_alloc(struct intel_context *ce)
3663 struct virtual_engine *ve = container_of(ce, typeof(*ve), context);
3665 return lrc_alloc(ce, ve->siblings[0]);
3668 static int virtual_context_pre_pin(struct intel_context *ce,
3669 struct i915_gem_ww_ctx *ww,
3672 struct virtual_engine *ve = container_of(ce, typeof(*ve), context);
3674 /* Note: we must use a real engine class for setting up reg state */
3675 return __execlists_context_pre_pin(ce, ve->siblings[0], ww, vaddr);
3678 static int virtual_context_pin(struct intel_context *ce, void *vaddr)
3680 struct virtual_engine *ve = container_of(ce, typeof(*ve), context);
3682 return lrc_pin(ce, ve->siblings[0], vaddr);
3685 static void virtual_context_enter(struct intel_context *ce)
3687 struct virtual_engine *ve = container_of(ce, typeof(*ve), context);
3690 for (n = 0; n < ve->num_siblings; n++)
3691 intel_engine_pm_get(ve->siblings[n]);
3693 intel_timeline_enter(ce->timeline);
3696 static void virtual_context_exit(struct intel_context *ce)
3698 struct virtual_engine *ve = container_of(ce, typeof(*ve), context);
3701 intel_timeline_exit(ce->timeline);
3703 for (n = 0; n < ve->num_siblings; n++)
3704 intel_engine_pm_put(ve->siblings[n]);
3707 static struct intel_engine_cs *
3708 virtual_get_sibling(struct intel_engine_cs *engine, unsigned int sibling)
3710 struct virtual_engine *ve = to_virtual_engine(engine);
3712 if (sibling >= ve->num_siblings)
3715 return ve->siblings[sibling];
3718 static const struct intel_context_ops virtual_context_ops = {
3719 .flags = COPS_HAS_INFLIGHT | COPS_RUNTIME_CYCLES,
3721 .alloc = virtual_context_alloc,
3723 .cancel_request = execlists_context_cancel_request,
3725 .pre_pin = virtual_context_pre_pin,
3726 .pin = virtual_context_pin,
3728 .post_unpin = lrc_post_unpin,
3730 .enter = virtual_context_enter,
3731 .exit = virtual_context_exit,
3733 .destroy = virtual_context_destroy,
3735 .get_sibling = virtual_get_sibling,
3738 static intel_engine_mask_t virtual_submission_mask(struct virtual_engine *ve)
3740 struct i915_request *rq;
3741 intel_engine_mask_t mask;
3743 rq = READ_ONCE(ve->request);
3747 /* The rq is ready for submission; rq->execution_mask is now stable. */
3748 mask = rq->execution_mask;
3749 if (unlikely(!mask)) {
3750 /* Invalid selection, submit to a random engine in error */
3751 i915_request_set_error_once(rq, -ENODEV);
3752 mask = ve->siblings[0]->mask;
3755 ENGINE_TRACE(&ve->base, "rq=%llx:%lld, mask=%x, prio=%d\n",
3756 rq->fence.context, rq->fence.seqno,
3757 mask, ve->base.sched_engine->queue_priority_hint);
3762 static void virtual_submission_tasklet(struct tasklet_struct *t)
3764 struct i915_sched_engine *sched_engine =
3765 from_tasklet(sched_engine, t, tasklet);
3766 struct virtual_engine * const ve =
3767 (struct virtual_engine *)sched_engine->private_data;
3768 const int prio = READ_ONCE(sched_engine->queue_priority_hint);
3769 intel_engine_mask_t mask;
3773 mask = virtual_submission_mask(ve);
3775 if (unlikely(!mask))
3778 for (n = 0; n < ve->num_siblings; n++) {
3779 struct intel_engine_cs *sibling = READ_ONCE(ve->siblings[n]);
3780 struct ve_node * const node = &ve->nodes[sibling->id];
3781 struct rb_node **parent, *rb;
3784 if (!READ_ONCE(ve->request))
3785 break; /* already handled by a sibling's tasklet */
3787 spin_lock_irq(&sibling->sched_engine->lock);
3789 if (unlikely(!(mask & sibling->mask))) {
3790 if (!RB_EMPTY_NODE(&node->rb)) {
3791 rb_erase_cached(&node->rb,
3792 &sibling->execlists.virtual);
3793 RB_CLEAR_NODE(&node->rb);
3799 if (unlikely(!RB_EMPTY_NODE(&node->rb))) {
3801 * Cheat and avoid rebalancing the tree if we can
3802 * reuse this node in situ.
3804 first = rb_first_cached(&sibling->execlists.virtual) ==
3806 if (prio == node->prio || (prio > node->prio && first))
3809 rb_erase_cached(&node->rb, &sibling->execlists.virtual);
3814 parent = &sibling->execlists.virtual.rb_root.rb_node;
3816 struct ve_node *other;
3819 other = rb_entry(rb, typeof(*other), rb);
3820 if (prio > other->prio) {
3821 parent = &rb->rb_left;
3823 parent = &rb->rb_right;
3828 rb_link_node(&node->rb, rb, parent);
3829 rb_insert_color_cached(&node->rb,
3830 &sibling->execlists.virtual,
3834 GEM_BUG_ON(RB_EMPTY_NODE(&node->rb));
3836 if (first && prio > sibling->sched_engine->queue_priority_hint)
3837 tasklet_hi_schedule(&sibling->sched_engine->tasklet);
3840 spin_unlock_irq(&sibling->sched_engine->lock);
3842 if (intel_context_inflight(&ve->context))
3847 static void virtual_submit_request(struct i915_request *rq)
3849 struct virtual_engine *ve = to_virtual_engine(rq->engine);
3850 unsigned long flags;
3852 ENGINE_TRACE(&ve->base, "rq=%llx:%lld\n",
3856 GEM_BUG_ON(ve->base.submit_request != virtual_submit_request);
3858 spin_lock_irqsave(&ve->base.sched_engine->lock, flags);
3860 /* By the time we resubmit a request, it may be completed */
3861 if (__i915_request_is_complete(rq)) {
3862 __i915_request_submit(rq);
3866 if (ve->request) { /* background completion from preempt-to-busy */
3867 GEM_BUG_ON(!__i915_request_is_complete(ve->request));
3868 __i915_request_submit(ve->request);
3869 i915_request_put(ve->request);
3872 ve->base.sched_engine->queue_priority_hint = rq_prio(rq);
3873 ve->request = i915_request_get(rq);
3875 GEM_BUG_ON(!list_empty(virtual_queue(ve)));
3876 list_move_tail(&rq->sched.link, virtual_queue(ve));
3878 tasklet_hi_schedule(&ve->base.sched_engine->tasklet);
3881 spin_unlock_irqrestore(&ve->base.sched_engine->lock, flags);
3884 static struct intel_context *
3885 execlists_create_virtual(struct intel_engine_cs **siblings, unsigned int count,
3886 unsigned long flags)
3888 struct virtual_engine *ve;
3892 ve = kzalloc(struct_size(ve, siblings, count), GFP_KERNEL);
3894 return ERR_PTR(-ENOMEM);
3896 ve->base.i915 = siblings[0]->i915;
3897 ve->base.gt = siblings[0]->gt;
3898 ve->base.uncore = siblings[0]->uncore;
3901 ve->base.class = OTHER_CLASS;
3902 ve->base.uabi_class = I915_ENGINE_CLASS_INVALID;
3903 ve->base.instance = I915_ENGINE_CLASS_INVALID_VIRTUAL;
3904 ve->base.uabi_instance = I915_ENGINE_CLASS_INVALID_VIRTUAL;
3907 * The decision on whether to submit a request using semaphores
3908 * depends on the saturated state of the engine. We only compute
3909 * this during HW submission of the request, and we need for this
3910 * state to be globally applied to all requests being submitted
3911 * to this engine. Virtual engines encompass more than one physical
3912 * engine and so we cannot accurately tell in advance if one of those
3913 * engines is already saturated and so cannot afford to use a semaphore
3914 * and be pessimized in priority for doing so -- if we are the only
3915 * context using semaphores after all other clients have stopped, we
3916 * will be starved on the saturated system. Such a global switch for
3917 * semaphores is less than ideal, but alas is the current compromise.
3919 ve->base.saturated = ALL_ENGINES;
3921 snprintf(ve->base.name, sizeof(ve->base.name), "virtual");
3923 intel_engine_init_execlists(&ve->base);
3925 ve->base.sched_engine = i915_sched_engine_create(ENGINE_VIRTUAL);
3926 if (!ve->base.sched_engine) {
3930 ve->base.sched_engine->private_data = &ve->base;
3932 ve->base.cops = &virtual_context_ops;
3933 ve->base.request_alloc = execlists_request_alloc;
3935 ve->base.sched_engine->schedule = i915_schedule;
3936 ve->base.sched_engine->kick_backend = kick_execlists;
3937 ve->base.submit_request = virtual_submit_request;
3939 INIT_LIST_HEAD(virtual_queue(ve));
3940 tasklet_setup(&ve->base.sched_engine->tasklet, virtual_submission_tasklet);
3942 intel_context_init(&ve->context, &ve->base);
3944 ve->base.breadcrumbs = intel_breadcrumbs_create(NULL);
3945 if (!ve->base.breadcrumbs) {
3950 for (n = 0; n < count; n++) {
3951 struct intel_engine_cs *sibling = siblings[n];
3953 GEM_BUG_ON(!is_power_of_2(sibling->mask));
3954 if (sibling->mask & ve->base.mask) {
3955 DRM_DEBUG("duplicate %s entry in load balancer\n",
3962 * The virtual engine implementation is tightly coupled to
3963 * the execlists backend -- we push out request directly
3964 * into a tree inside each physical engine. We could support
3965 * layering if we handle cloning of the requests and
3966 * submitting a copy into each backend.
3968 if (sibling->sched_engine->tasklet.callback !=
3969 execlists_submission_tasklet) {
3974 GEM_BUG_ON(RB_EMPTY_NODE(&ve->nodes[sibling->id].rb));
3975 RB_CLEAR_NODE(&ve->nodes[sibling->id].rb);
3977 ve->siblings[ve->num_siblings++] = sibling;
3978 ve->base.mask |= sibling->mask;
3979 ve->base.logical_mask |= sibling->logical_mask;
3982 * All physical engines must be compatible for their emission
3983 * functions (as we build the instructions during request
3984 * construction and do not alter them before submission
3985 * on the physical engine). We use the engine class as a guide
3986 * here, although that could be refined.
3988 if (ve->base.class != OTHER_CLASS) {
3989 if (ve->base.class != sibling->class) {
3990 DRM_DEBUG("invalid mixing of engine class, sibling %d, already %d\n",
3991 sibling->class, ve->base.class);
3998 ve->base.class = sibling->class;
3999 ve->base.uabi_class = sibling->uabi_class;
4000 snprintf(ve->base.name, sizeof(ve->base.name),
4001 "v%dx%d", ve->base.class, count);
4002 ve->base.context_size = sibling->context_size;
4004 ve->base.add_active_request = sibling->add_active_request;
4005 ve->base.remove_active_request = sibling->remove_active_request;
4006 ve->base.emit_bb_start = sibling->emit_bb_start;
4007 ve->base.emit_flush = sibling->emit_flush;
4008 ve->base.emit_init_breadcrumb = sibling->emit_init_breadcrumb;
4009 ve->base.emit_fini_breadcrumb = sibling->emit_fini_breadcrumb;
4010 ve->base.emit_fini_breadcrumb_dw =
4011 sibling->emit_fini_breadcrumb_dw;
4013 ve->base.flags = sibling->flags;
4016 ve->base.flags |= I915_ENGINE_IS_VIRTUAL;
4018 virtual_engine_initial_hint(ve);
4019 return &ve->context;
4022 intel_context_put(&ve->context);
4023 return ERR_PTR(err);
4026 void intel_execlists_show_requests(struct intel_engine_cs *engine,
4027 struct drm_printer *m,
4028 void (*show_request)(struct drm_printer *m,
4029 const struct i915_request *rq,
4034 const struct intel_engine_execlists *execlists = &engine->execlists;
4035 struct i915_sched_engine *sched_engine = engine->sched_engine;
4036 struct i915_request *rq, *last;
4037 unsigned long flags;
4041 spin_lock_irqsave(&sched_engine->lock, flags);
4045 list_for_each_entry(rq, &sched_engine->requests, sched.link) {
4046 if (count++ < max - 1)
4047 show_request(m, rq, "\t\t", 0);
4054 "\t\t...skipping %d executing requests...\n",
4057 show_request(m, last, "\t\t", 0);
4060 if (sched_engine->queue_priority_hint != INT_MIN)
4061 drm_printf(m, "\t\tQueue priority hint: %d\n",
4062 READ_ONCE(sched_engine->queue_priority_hint));
4066 for (rb = rb_first_cached(&sched_engine->queue); rb; rb = rb_next(rb)) {
4067 struct i915_priolist *p = rb_entry(rb, typeof(*p), node);
4069 priolist_for_each_request(rq, p) {
4070 if (count++ < max - 1)
4071 show_request(m, rq, "\t\t", 0);
4079 "\t\t...skipping %d queued requests...\n",
4082 show_request(m, last, "\t\t", 0);
4087 for (rb = rb_first_cached(&execlists->virtual); rb; rb = rb_next(rb)) {
4088 struct virtual_engine *ve =
4089 rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
4090 struct i915_request *rq = READ_ONCE(ve->request);
4093 if (count++ < max - 1)
4094 show_request(m, rq, "\t\t", 0);
4102 "\t\t...skipping %d virtual requests...\n",
4105 show_request(m, last, "\t\t", 0);
4108 spin_unlock_irqrestore(&sched_engine->lock, flags);
4111 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
4112 #include "selftest_execlists.c"