diff options
Diffstat (limited to 'drivers/gpu/drm/i915/gt/intel_execlists_submission.c')
-rw-r--r-- | drivers/gpu/drm/i915/gt/intel_execlists_submission.c | 3896 |
1 files changed, 3896 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c new file mode 100644 index 000000000000..ac1be7a632d3 --- /dev/null +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c @@ -0,0 +1,3896 @@ +// SPDX-License-Identifier: MIT +/* + * Copyright © 2014 Intel Corporation + */ + +/** + * DOC: Logical Rings, Logical Ring Contexts and Execlists + * + * Motivation: + * GEN8 brings an expansion of the HW contexts: "Logical Ring Contexts". + * These expanded contexts enable a number of new abilities, especially + * "Execlists" (also implemented in this file). + * + * One of the main differences with the legacy HW contexts is that logical + * ring contexts incorporate many more things to the context's state, like + * PDPs or ringbuffer control registers: + * + * The reason why PDPs are included in the context is straightforward: as + * PPGTTs (per-process GTTs) are actually per-context, having the PDPs + * contained there mean you don't need to do a ppgtt->switch_mm yourself, + * instead, the GPU will do it for you on the context switch. + * + * But, what about the ringbuffer control registers (head, tail, etc..)? + * shouldn't we just need a set of those per engine command streamer? This is + * where the name "Logical Rings" starts to make sense: by virtualizing the + * rings, the engine cs shifts to a new "ring buffer" with every context + * switch. When you want to submit a workload to the GPU you: A) choose your + * context, B) find its appropriate virtualized ring, C) write commands to it + * and then, finally, D) tell the GPU to switch to that context. + * + * Instead of the legacy MI_SET_CONTEXT, the way you tell the GPU to switch + * to a contexts is via a context execution list, ergo "Execlists". + * + * LRC implementation: + * Regarding the creation of contexts, we have: + * + * - One global default context. + * - One local default context for each opened fd. + * - One local extra context for each context create ioctl call. + * + * Now that ringbuffers belong per-context (and not per-engine, like before) + * and that contexts are uniquely tied to a given engine (and not reusable, + * like before) we need: + * + * - One ringbuffer per-engine inside each context. + * - One backing object per-engine inside each context. + * + * The global default context starts its life with these new objects fully + * allocated and populated. The local default context for each opened fd is + * more complex, because we don't know at creation time which engine is going + * to use them. To handle this, we have implemented a deferred creation of LR + * contexts: + * + * The local context starts its life as a hollow or blank holder, that only + * gets populated for a given engine once we receive an execbuffer. If later + * on we receive another execbuffer ioctl for the same context but a different + * engine, we allocate/populate a new ringbuffer and context backing object and + * so on. + * + * Finally, regarding local contexts created using the ioctl call: as they are + * only allowed with the render ring, we can allocate & populate them right + * away (no need to defer anything, at least for now). + * + * Execlists implementation: + * Execlists are the new method by which, on gen8+ hardware, workloads are + * submitted for execution (as opposed to the legacy, ringbuffer-based, method). + * This method works as follows: + * + * When a request is committed, its commands (the BB start and any leading or + * trailing commands, like the seqno breadcrumbs) are placed in the ringbuffer + * for the appropriate context. The tail pointer in the hardware context is not + * updated at this time, but instead, kept by the driver in the ringbuffer + * structure. A structure representing this request is added to a request queue + * for the appropriate engine: this structure contains a copy of the context's + * tail after the request was written to the ring buffer and a pointer to the + * context itself. + * + * If the engine's request queue was empty before the request was added, the + * queue is processed immediately. Otherwise the queue will be processed during + * a context switch interrupt. In any case, elements on the queue will get sent + * (in pairs) to the GPU's ExecLists Submit Port (ELSP, for short) with a + * globally unique 20-bits submission ID. + * + * When execution of a request completes, the GPU updates the context status + * buffer with a context complete event and generates a context switch interrupt. + * During the interrupt handling, the driver examines the events in the buffer: + * for each context complete event, if the announced ID matches that on the head + * of the request queue, then that request is retired and removed from the queue. + * + * After processing, if any requests were retired and the queue is not empty + * then a new execution list can be submitted. The two requests at the front of + * the queue are next to be submitted but since a context may not occur twice in + * an execution list, if subsequent requests have the same ID as the first then + * the two requests must be combined. This is done simply by discarding requests + * at the head of the queue until either only one requests is left (in which case + * we use a NULL second context) or the first two requests have unique IDs. + * + * By always executing the first two requests in the queue the driver ensures + * that the GPU is kept as busy as possible. In the case where a single context + * completes but a second context is still executing, the request for this second + * context will be at the head of the queue when we remove the first one. This + * request will then be resubmitted along with a new request for a different context, + * which will cause the hardware to continue executing the second request and queue + * the new request (the GPU detects the condition of a context getting preempted + * with the same context and optimizes the context switch flow by not doing + * preemption, but just sampling the new tail pointer). + * + */ +#include <linux/interrupt.h> + +#include "i915_drv.h" +#include "i915_trace.h" +#include "i915_vgpu.h" +#include "gen8_engine_cs.h" +#include "intel_breadcrumbs.h" +#include "intel_context.h" +#include "intel_engine_pm.h" +#include "intel_engine_stats.h" +#include "intel_execlists_submission.h" +#include "intel_gt.h" +#include "intel_gt_pm.h" +#include "intel_gt_requests.h" +#include "intel_lrc.h" +#include "intel_lrc_reg.h" +#include "intel_mocs.h" +#include "intel_reset.h" +#include "intel_ring.h" +#include "intel_workarounds.h" +#include "shmem_utils.h" + +#define RING_EXECLIST_QFULL (1 << 0x2) +#define RING_EXECLIST1_VALID (1 << 0x3) +#define RING_EXECLIST0_VALID (1 << 0x4) +#define RING_EXECLIST_ACTIVE_STATUS (3 << 0xE) +#define RING_EXECLIST1_ACTIVE (1 << 0x11) +#define RING_EXECLIST0_ACTIVE (1 << 0x12) + +#define GEN8_CTX_STATUS_IDLE_ACTIVE (1 << 0) +#define GEN8_CTX_STATUS_PREEMPTED (1 << 1) +#define GEN8_CTX_STATUS_ELEMENT_SWITCH (1 << 2) +#define GEN8_CTX_STATUS_ACTIVE_IDLE (1 << 3) +#define GEN8_CTX_STATUS_COMPLETE (1 << 4) +#define GEN8_CTX_STATUS_LITE_RESTORE (1 << 15) + +#define GEN8_CTX_STATUS_COMPLETED_MASK \ + (GEN8_CTX_STATUS_COMPLETE | GEN8_CTX_STATUS_PREEMPTED) + +#define GEN12_CTX_STATUS_SWITCHED_TO_NEW_QUEUE (0x1) /* lower csb dword */ +#define GEN12_CTX_SWITCH_DETAIL(csb_dw) ((csb_dw) & 0xF) /* upper csb dword */ +#define GEN12_CSB_SW_CTX_ID_MASK GENMASK(25, 15) +#define GEN12_IDLE_CTX_ID 0x7FF +#define GEN12_CSB_CTX_VALID(csb_dw) \ + (FIELD_GET(GEN12_CSB_SW_CTX_ID_MASK, csb_dw) != GEN12_IDLE_CTX_ID) + +/* Typical size of the average request (2 pipecontrols and a MI_BB) */ +#define EXECLISTS_REQUEST_SIZE 64 /* bytes */ + +struct virtual_engine { + struct intel_engine_cs base; + struct intel_context context; + struct rcu_work rcu; + + /* + * We allow only a single request through the virtual engine at a time + * (each request in the timeline waits for the completion fence of + * the previous before being submitted). By restricting ourselves to + * only submitting a single request, each request is placed on to a + * physical to maximise load spreading (by virtue of the late greedy + * scheduling -- each real engine takes the next available request + * upon idling). + */ + struct i915_request *request; + + /* + * We keep a rbtree of available virtual engines inside each physical + * engine, sorted by priority. Here we preallocate the nodes we need + * for the virtual engine, indexed by physical_engine->id. + */ + struct ve_node { + struct rb_node rb; + int prio; + } nodes[I915_NUM_ENGINES]; + + /* + * Keep track of bonded pairs -- restrictions upon on our selection + * of physical engines any particular request may be submitted to. + * If we receive a submit-fence from a master engine, we will only + * use one of sibling_mask physical engines. + */ + struct ve_bond { + const struct intel_engine_cs *master; + intel_engine_mask_t sibling_mask; + } *bonds; + unsigned int num_bonds; + + /* And finally, which physical engines this virtual engine maps onto. */ + unsigned int num_siblings; + struct intel_engine_cs *siblings[]; +}; + +static struct virtual_engine *to_virtual_engine(struct intel_engine_cs *engine) +{ + GEM_BUG_ON(!intel_engine_is_virtual(engine)); + return container_of(engine, struct virtual_engine, base); +} + +static struct i915_request * +__active_request(const struct intel_timeline * const tl, + struct i915_request *rq, + int error) +{ + struct i915_request *active = rq; + + list_for_each_entry_from_reverse(rq, &tl->requests, link) { + if (__i915_request_is_complete(rq)) + break; + + if (error) { + i915_request_set_error_once(rq, error); + __i915_request_skip(rq); + } + active = rq; + } + + return active; +} + +static struct i915_request * +active_request(const struct intel_timeline * const tl, struct i915_request *rq) +{ + return __active_request(tl, rq, 0); +} + +static void ring_set_paused(const struct intel_engine_cs *engine, int state) +{ + /* + * We inspect HWS_PREEMPT with a semaphore inside + * engine->emit_fini_breadcrumb. If the dword is true, + * the ring is paused as the semaphore will busywait + * until the dword is false. + */ + engine->status_page.addr[I915_GEM_HWS_PREEMPT] = state; + if (state) + wmb(); +} + +static struct i915_priolist *to_priolist(struct rb_node *rb) +{ + return rb_entry(rb, struct i915_priolist, node); +} + +static int rq_prio(const struct i915_request *rq) +{ + return READ_ONCE(rq->sched.attr.priority); +} + +static int effective_prio(const struct i915_request *rq) +{ + int prio = rq_prio(rq); + + /* + * If this request is special and must not be interrupted at any + * cost, so be it. Note we are only checking the most recent request + * in the context and so may be masking an earlier vip request. It + * is hoped that under the conditions where nopreempt is used, this + * will not matter (i.e. all requests to that context will be + * nopreempt for as long as desired). + */ + if (i915_request_has_nopreempt(rq)) + prio = I915_PRIORITY_UNPREEMPTABLE; + + return prio; +} + +static int queue_prio(const struct intel_engine_execlists *execlists) +{ + struct i915_priolist *p; + struct rb_node *rb; + + rb = rb_first_cached(&execlists->queue); + if (!rb) + return INT_MIN; + + /* + * As the priolist[] are inverted, with the highest priority in [0], + * we have to flip the index value to become priority. + */ + p = to_priolist(rb); + if (!I915_USER_PRIORITY_SHIFT) + return p->priority; + + return ((p->priority + 1) << I915_USER_PRIORITY_SHIFT) - ffs(p->used); +} + +static int virtual_prio(const struct intel_engine_execlists *el) +{ + struct rb_node *rb = rb_first_cached(&el->virtual); + + return rb ? rb_entry(rb, struct ve_node, rb)->prio : INT_MIN; +} + +static bool need_preempt(const struct intel_engine_cs *engine, + const struct i915_request *rq) +{ + int last_prio; + + if (!intel_engine_has_semaphores(engine)) + return false; + + /* + * Check if the current priority hint merits a preemption attempt. + * + * We record the highest value priority we saw during rescheduling + * prior to this dequeue, therefore we know that if it is strictly + * less than the current tail of ESLP[0], we do not need to force + * a preempt-to-idle cycle. + * + * However, the priority hint is a mere hint that we may need to + * preempt. If that hint is stale or we may be trying to preempt + * ourselves, ignore the request. + * + * More naturally we would write + * prio >= max(0, last); + * except that we wish to prevent triggering preemption at the same + * priority level: the task that is running should remain running + * to preserve FIFO ordering of dependencies. + */ + last_prio = max(effective_prio(rq), I915_PRIORITY_NORMAL - 1); + if (engine->execlists.queue_priority_hint <= last_prio) + return false; + + /* + * Check against the first request in ELSP[1], it will, thanks to the + * power of PI, be the highest priority of that context. + */ + if (!list_is_last(&rq->sched.link, &engine->active.requests) && + rq_prio(list_next_entry(rq, sched.link)) > last_prio) + return true; + + /* + * If the inflight context did not trigger the preemption, then maybe + * it was the set of queued requests? Pick the highest priority in + * the queue (the first active priolist) and see if it deserves to be + * running instead of ELSP[0]. + * + * The highest priority request in the queue can not be either + * ELSP[0] or ELSP[1] as, thanks again to PI, if it was the same + * context, it's priority would not exceed ELSP[0] aka last_prio. + */ + return max(virtual_prio(&engine->execlists), + queue_prio(&engine->execlists)) > last_prio; +} + +__maybe_unused static bool +assert_priority_queue(const struct i915_request *prev, + const struct i915_request *next) +{ + /* + * Without preemption, the prev may refer to the still active element + * which we refuse to let go. + * + * Even with preemption, there are times when we think it is better not + * to preempt and leave an ostensibly lower priority request in flight. + */ + if (i915_request_is_active(prev)) + return true; + + return rq_prio(prev) >= rq_prio(next); +} + +static struct i915_request * +__unwind_incomplete_requests(struct intel_engine_cs *engine) +{ + struct i915_request *rq, *rn, *active = NULL; + struct list_head *pl; + int prio = I915_PRIORITY_INVALID; + + lockdep_assert_held(&engine->active.lock); + + list_for_each_entry_safe_reverse(rq, rn, + &engine->active.requests, + sched.link) { + if (__i915_request_is_complete(rq)) { + list_del_init(&rq->sched.link); + continue; + } + + __i915_request_unsubmit(rq); + + GEM_BUG_ON(rq_prio(rq) == I915_PRIORITY_INVALID); + if (rq_prio(rq) != prio) { + prio = rq_prio(rq); + pl = i915_sched_lookup_priolist(engine, prio); + } + GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root)); + + list_move(&rq->sched.link, pl); + set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags); + + /* Check in case we rollback so far we wrap [size/2] */ + if (intel_ring_direction(rq->ring, + rq->tail, + rq->ring->tail + 8) > 0) + rq->context->lrc.desc |= CTX_DESC_FORCE_RESTORE; + + active = rq; + } + + return active; +} + +struct i915_request * +execlists_unwind_incomplete_requests(struct intel_engine_execlists *execlists) +{ + struct intel_engine_cs *engine = + container_of(execlists, typeof(*engine), execlists); + + return __unwind_incomplete_requests(engine); +} + +static void +execlists_context_status_change(struct i915_request *rq, unsigned long status) +{ + /* + * Only used when GVT-g is enabled now. When GVT-g is disabled, + * The compiler should eliminate this function as dead-code. + */ + if (!IS_ENABLED(CONFIG_DRM_I915_GVT)) + return; + + atomic_notifier_call_chain(&rq->engine->context_status_notifier, + status, rq); +} + +static void reset_active(struct i915_request *rq, + struct intel_engine_cs *engine) +{ + struct intel_context * const ce = rq->context; + u32 head; + + /* + * The executing context has been cancelled. We want to prevent + * further execution along this context and propagate the error on + * to anything depending on its results. + * + * In __i915_request_submit(), we apply the -EIO and remove the + * requests' payloads for any banned requests. But first, we must + * rewind the context back to the start of the incomplete request so + * that we do not jump back into the middle of the batch. + * + * We preserve the breadcrumbs and semaphores of the incomplete + * requests so that inter-timeline dependencies (i.e other timelines) + * remain correctly ordered. And we defer to __i915_request_submit() + * so that all asynchronous waits are correctly handled. + */ + ENGINE_TRACE(engine, "{ reset rq=%llx:%lld }\n", + rq->fence.context, rq->fence.seqno); + + /* On resubmission of the active request, payload will be scrubbed */ + if (__i915_request_is_complete(rq)) + head = rq->tail; + else + head = __active_request(ce->timeline, rq, -EIO)->head; + head = intel_ring_wrap(ce->ring, head); + + /* Scrub the context image to prevent replaying the previous batch */ + lrc_init_regs(ce, engine, true); + + /* We've switched away, so this should be a no-op, but intent matters */ + ce->lrc.lrca = lrc_update_regs(ce, engine, head); +} + +static struct intel_engine_cs * +__execlists_schedule_in(struct i915_request *rq) +{ + struct intel_engine_cs * const engine = rq->engine; + struct intel_context * const ce = rq->context; + + intel_context_get(ce); + + if (unlikely(intel_context_is_closed(ce) && + !intel_engine_has_heartbeat(engine))) + intel_context_set_banned(ce); + + if (unlikely(intel_context_is_banned(ce))) + reset_active(rq, engine); + + if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) + lrc_check_regs(ce, engine, "before"); + + if (ce->tag) { + /* Use a fixed tag for OA and friends */ + GEM_BUG_ON(ce->tag <= BITS_PER_LONG); + ce->lrc.ccid = ce->tag; + } else { + /* We don't need a strict matching tag, just different values */ + unsigned int tag = __ffs(engine->context_tag); + + GEM_BUG_ON(tag >= BITS_PER_LONG); + __clear_bit(tag, &engine->context_tag); + ce->lrc.ccid = (1 + tag) << (GEN11_SW_CTX_ID_SHIFT - 32); + + BUILD_BUG_ON(BITS_PER_LONG > GEN12_MAX_CONTEXT_HW_ID); + } + + ce->lrc.ccid |= engine->execlists.ccid; + + __intel_gt_pm_get(engine->gt); + if (engine->fw_domain && !engine->fw_active++) + intel_uncore_forcewake_get(engine->uncore, engine->fw_domain); + execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_IN); + intel_engine_context_in(engine); + + CE_TRACE(ce, "schedule-in, ccid:%x\n", ce->lrc.ccid); + + return engine; +} + +static void execlists_schedule_in(struct i915_request *rq, int idx) +{ + struct intel_context * const ce = rq->context; + struct intel_engine_cs *old; + + GEM_BUG_ON(!intel_engine_pm_is_awake(rq->engine)); + trace_i915_request_in(rq, idx); + + old = ce->inflight; + if (!old) + old = __execlists_schedule_in(rq); + WRITE_ONCE(ce->inflight, ptr_inc(old)); + + GEM_BUG_ON(intel_context_inflight(ce) != rq->engine); +} + +static void +resubmit_virtual_request(struct i915_request *rq, struct virtual_engine *ve) +{ + struct intel_engine_cs *engine = rq->engine; + + spin_lock_irq(&engine->active.lock); + + clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags); + WRITE_ONCE(rq->engine, &ve->base); + ve->base.submit_request(rq); + + spin_unlock_irq(&engine->active.lock); +} + +static void kick_siblings(struct i915_request *rq, struct intel_context *ce) +{ + struct virtual_engine *ve = container_of(ce, typeof(*ve), context); + struct intel_engine_cs *engine = rq->engine; + + /* + * After this point, the rq may be transferred to a new sibling, so + * before we clear ce->inflight make sure that the context has been + * removed from the b->signalers and furthermore we need to make sure + * that the concurrent iterator in signal_irq_work is no longer + * following ce->signal_link. + */ + if (!list_empty(&ce->signals)) + intel_context_remove_breadcrumbs(ce, engine->breadcrumbs); + + /* + * This engine is now too busy to run this virtual request, so + * see if we can find an alternative engine for it to execute on. + * Once a request has become bonded to this engine, we treat it the + * same as other native request. + */ + if (i915_request_in_priority_queue(rq) && + rq->execution_mask != engine->mask) + resubmit_virtual_request(rq, ve); + + if (READ_ONCE(ve->request)) + tasklet_hi_schedule(&ve->base.execlists.tasklet); +} + +static void __execlists_schedule_out(struct i915_request * const rq, + struct intel_context * const ce) +{ + struct intel_engine_cs * const engine = rq->engine; + unsigned int ccid; + + /* + * NB process_csb() is not under the engine->active.lock and hence + * schedule_out can race with schedule_in meaning that we should + * refrain from doing non-trivial work here. + */ + + CE_TRACE(ce, "schedule-out, ccid:%x\n", ce->lrc.ccid); + GEM_BUG_ON(ce->inflight != engine); + + if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) + lrc_check_regs(ce, engine, "after"); + + /* + * If we have just completed this context, the engine may now be + * idle and we want to re-enter powersaving. + */ + if (intel_timeline_is_last(ce->timeline, rq) && + __i915_request_is_complete(rq)) + intel_engine_add_retire(engine, ce->timeline); + + ccid = ce->lrc.ccid; + ccid >>= GEN11_SW_CTX_ID_SHIFT - 32; + ccid &= GEN12_MAX_CONTEXT_HW_ID; + if (ccid < BITS_PER_LONG) { + GEM_BUG_ON(ccid == 0); + GEM_BUG_ON(test_bit(ccid - 1, &engine->context_tag)); + __set_bit(ccid - 1, &engine->context_tag); + } + + lrc_update_runtime(ce); + intel_engine_context_out(engine); + execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_OUT); + if (engine->fw_domain && !--engine->fw_active) + intel_uncore_forcewake_put(engine->uncore, engine->fw_domain); + intel_gt_pm_put_async(engine->gt); + + /* + * If this is part of a virtual engine, its next request may + * have been blocked waiting for access to the active context. + * We have to kick all the siblings again in case we need to + * switch (e.g. the next request is not runnable on this + * engine). Hopefully, we will already have submitted the next + * request before the tasklet runs and do not need to rebuild + * each virtual tree and kick everyone again. + */ + if (ce->engine != engine) + kick_siblings(rq, ce); + + WRITE_ONCE(ce->inflight, NULL); + intel_context_put(ce); +} + +static inline void execlists_schedule_out(struct i915_request *rq) +{ + struct intel_context * const ce = rq->context; + + trace_i915_request_out(rq); + + GEM_BUG_ON(!ce->inflight); + ce->inflight = ptr_dec(ce->inflight); + if (!__intel_context_inflight_count(ce->inflight)) + __execlists_schedule_out(rq, ce); + + i915_request_put(rq); +} + +static u64 execlists_update_context(struct i915_request *rq) +{ + struct intel_context *ce = rq->context; + u64 desc = ce->lrc.desc; + u32 tail, prev; + + /* + * WaIdleLiteRestore:bdw,skl + * + * We should never submit the context with the same RING_TAIL twice + * just in case we submit an empty ring, which confuses the HW. + * + * We append a couple of NOOPs (gen8_emit_wa_tail) after the end of + * the normal request to be able to always advance the RING_TAIL on + * subsequent resubmissions (for lite restore). Should that fail us, + * and we try and submit the same tail again, force the context + * reload. + * + * If we need to return to a preempted context, we need to skip the + * lite-restore and force it to reload the RING_TAIL. Otherwise, the + * HW has a tendency to ignore us rewinding the TAIL to the end of + * an earlier request. + */ + GEM_BUG_ON(ce->lrc_reg_state[CTX_RING_TAIL] != rq->ring->tail); + prev = rq->ring->tail; + tail = intel_ring_set_tail(rq->ring, rq->tail); + if (unlikely(intel_ring_direction(rq->ring, tail, prev) <= 0)) + desc |= CTX_DESC_FORCE_RESTORE; + ce->lrc_reg_state[CTX_RING_TAIL] = tail; + rq->tail = rq->wa_tail; + + /* + * Make sure the context image is complete before we submit it to HW. + * + * Ostensibly, writes (including the WCB) should be flushed prior to + * an uncached write such as our mmio register access, the empirical + * evidence (esp. on Braswell) suggests that the WC write into memory + * may not be visible to the HW prior to the completion of the UC + * register write and that we may begin execution from the context + * before its image is complete leading to invalid PD chasing. + */ + wmb(); + + ce->lrc.desc &= ~CTX_DESC_FORCE_RESTORE; + return desc; +} + +static void write_desc(struct intel_engine_execlists *execlists, u64 desc, u32 port) +{ + if (execlists->ctrl_reg) { + writel(lower_32_bits(desc), execlists->submit_reg + port * 2); + writel(upper_32_bits(desc), execlists->submit_reg + port * 2 + 1); + } else { + writel(upper_32_bits(desc), execlists->submit_reg); + writel(lower_32_bits(desc), execlists->submit_reg); + } +} + +static __maybe_unused char * +dump_port(char *buf, int buflen, const char *prefix, struct i915_request *rq) +{ + if (!rq) + return ""; + + snprintf(buf, buflen, "%sccid:%x %llx:%lld%s prio %d", + prefix, + rq->context->lrc.ccid, + rq->fence.context, rq->fence.seqno, + __i915_request_is_complete(rq) ? "!" : + __i915_request_has_started(rq) ? "*" : + "", + rq_prio(rq)); + + return buf; +} + +static __maybe_unused noinline void +trace_ports(const struct intel_engine_execlists *execlists, + const char *msg, + struct i915_request * const *ports) +{ + const struct intel_engine_cs *engine = + container_of(execlists, typeof(*engine), execlists); + char __maybe_unused p0[40], p1[40]; + + if (!ports[0]) + return; + + ENGINE_TRACE(engine, "%s { %s%s }\n", msg, + dump_port(p0, sizeof(p0), "", ports[0]), + dump_port(p1, sizeof(p1), ", ", ports[1])); +} + +static bool +reset_in_progress(const struct intel_engine_execlists *execlists) +{ + return unlikely(!__tasklet_is_enabled(&execlists->tasklet)); +} + +static __maybe_unused noinline bool +assert_pending_valid(const struct intel_engine_execlists *execlists, + const char *msg) +{ + struct intel_engine_cs *engine = + container_of(execlists, typeof(*engine), execlists); + struct i915_request * const *port, *rq; + struct intel_context *ce = NULL; + bool sentinel = false; + u32 ccid = -1; + + trace_ports(execlists, msg, execlists->pending); + + /* We may be messing around with the lists during reset, lalala */ + if (reset_in_progress(execlists)) + return true; + + if (!execlists->pending[0]) { + GEM_TRACE_ERR("%s: Nothing pending for promotion!\n", + engine->name); + return false; + } + + if (execlists->pending[execlists_num_ports(execlists)]) { + GEM_TRACE_ERR("%s: Excess pending[%d] for promotion!\n", + engine->name, execlists_num_ports(execlists)); + return false; + } + + for (port = execlists->pending; (rq = *port); port++) { + unsigned long flags; + bool ok = true; + + GEM_BUG_ON(!kref_read(&rq->fence.refcount)); + GEM_BUG_ON(!i915_request_is_active(rq)); + + if (ce == rq->context) { + GEM_TRACE_ERR("%s: Dup context:%llx in pending[%zd]\n", + engine->name, + ce->timeline->fence_context, + port - execlists->pending); + return false; + } + ce = rq->context; + + if (ccid == ce->lrc.ccid) { + GEM_TRACE_ERR("%s: Dup ccid:%x context:%llx in pending[%zd]\n", + engine->name, + ccid, ce->timeline->fence_context, + port - execlists->pending); + return false; + } + ccid = ce->lrc.ccid; + + /* + * Sentinels are supposed to be the last request so they flush + * the current execution off the HW. Check that they are the only + * request in the pending submission. + */ + if (sentinel) { + GEM_TRACE_ERR("%s: context:%llx after sentinel in pending[%zd]\n", + engine->name, + ce->timeline->fence_context, + port - execlists->pending); + return false; + } + sentinel = i915_request_has_sentinel(rq); + + /* + * We want virtual requests to only be in the first slot so + * that they are never stuck behind a hog and can be immediately + * transferred onto the next idle engine. + */ + if (rq->execution_mask != engine->mask && + port != execlists->pending) { + GEM_TRACE_ERR("%s: virtual engine:%llx not in prime position[%zd]\n", + engine->name, + ce->timeline->fence_context, + port - execlists->pending); + return false; + } + + /* Hold tightly onto the lock to prevent concurrent retires! */ + if (!spin_trylock_irqsave(&rq->lock, flags)) + continue; + + if (__i915_request_is_complete(rq)) + goto unlock; + + if (i915_active_is_idle(&ce->active) && + !intel_context_is_barrier(ce)) { + GEM_TRACE_ERR("%s: Inactive context:%llx in pending[%zd]\n", + engine->name, + ce->timeline->fence_context, + port - execlists->pending); + ok = false; + goto unlock; + } + + if (!i915_vma_is_pinned(ce->state)) { + GEM_TRACE_ERR("%s: Unpinned context:%llx in pending[%zd]\n", + engine->name, + ce->timeline->fence_context, + port - execlists->pending); + ok = false; + goto unlock; + } + + if (!i915_vma_is_pinned(ce->ring->vma)) { + GEM_TRACE_ERR("%s: Unpinned ring:%llx in pending[%zd]\n", + engine->name, + ce->timeline->fence_context, + port - execlists->pending); + ok = false; + goto unlock; + } + +unlock: + spin_unlock_irqrestore(&rq->lock, flags); + if (!ok) + return false; + } + + return ce; +} + +static void execlists_submit_ports(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists *execlists = &engine->execlists; + unsigned int n; + + GEM_BUG_ON(!assert_pending_valid(execlists, "submit")); + + /* + * We can skip acquiring intel_runtime_pm_get() here as it was taken + * on our behalf by the request (see i915_gem_mark_busy()) and it will + * not be relinquished until the device is idle (see + * i915_gem_idle_work_handler()). As a precaution, we make sure + * that all ELSP are drained i.e. we have processed the CSB, + * before allowing ourselves to idle and calling intel_runtime_pm_put(). + */ + GEM_BUG_ON(!intel_engine_pm_is_awake(engine)); + + /* + * ELSQ note: the submit queue is not cleared after being submitted + * to the HW so we need to make sure we always clean it up. This is + * currently ensured by the fact that we always write the same number + * of elsq entries, keep this in mind before changing the loop below. + */ + for (n = execlists_num_ports(execlists); n--; ) { + struct i915_request *rq = execlists->pending[n]; + + write_desc(execlists, + rq ? execlists_update_context(rq) : 0, + n); + } + + /* we need to manually load the submit queue */ + if (execlists->ctrl_reg) + writel(EL_CTRL_LOAD, execlists->ctrl_reg); +} + +static bool ctx_single_port_submission(const struct intel_context *ce) +{ + return (IS_ENABLED(CONFIG_DRM_I915_GVT) && + intel_context_force_single_submission(ce)); +} + +static bool can_merge_ctx(const struct intel_context *prev, + const struct intel_context *next) +{ + if (prev != next) + return false; + + if (ctx_single_port_submission(prev)) + return false; + + return true; +} + +static unsigned long i915_request_flags(const struct i915_request *rq) +{ + return READ_ONCE(rq->fence.flags); +} + +static bool can_merge_rq(const struct i915_request *prev, + const struct i915_request *next) +{ + GEM_BUG_ON(prev == next); + GEM_BUG_ON(!assert_priority_queue(prev, next)); + + /* + * We do not submit known completed requests. Therefore if the next + * request is already completed, we can pretend to merge it in + * with the previous context (and we will skip updating the ELSP + * and tracking). Thus hopefully keeping the ELSP full with active + * contexts, despite the best efforts of preempt-to-busy to confuse + * us. + */ + if (__i915_request_is_complete(next)) + return true; + + if (unlikely((i915_request_flags(prev) ^ i915_request_flags(next)) & + (BIT(I915_FENCE_FLAG_NOPREEMPT) | + BIT(I915_FENCE_FLAG_SENTINEL)))) + return false; + + if (!can_merge_ctx(prev->context, next->context)) + return false; + + GEM_BUG_ON(i915_seqno_passed(prev->fence.seqno, next->fence.seqno)); + return true; +} + +static bool virtual_matches(const struct virtual_engine *ve, + const struct i915_request *rq, + const struct intel_engine_cs *engine) +{ + const struct intel_engine_cs *inflight; + + if (!rq) + return false; + + if (!(rq->execution_mask & engine->mask)) /* We peeked too soon! */ + return false; + + /* + * We track when the HW has completed saving the context image + * (i.e. when we have seen the final CS event switching out of + * the context) and must not overwrite the context image before + * then. This restricts us to only using the active engine + * while the previous virtualized request is inflight (so + * we reuse the register offsets). This is a very small + * hystersis on the greedy seelction algorithm. + */ + inflight = intel_context_inflight(&ve->context); + if (inflight && inflight != engine) + return false; + + return true; +} + +static struct virtual_engine * +first_virtual_engine(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists *el = &engine->execlists; + struct rb_node *rb = rb_first_cached(&el->virtual); + + while (rb) { + struct virtual_engine *ve = + rb_entry(rb, typeof(*ve), nodes[engine->id].rb); + struct i915_request *rq = READ_ONCE(ve->request); + + /* lazily cleanup after another engine handled rq */ + if (!rq || !virtual_matches(ve, rq, engine)) { + rb_erase_cached(rb, &el->virtual); + RB_CLEAR_NODE(rb); + rb = rb_first_cached(&el->virtual); + continue; + } + + return ve; + } + + return NULL; +} + +static void virtual_xfer_context(struct virtual_engine *ve, + struct intel_engine_cs *engine) +{ + unsigned int n; + + if (likely(engine == ve->siblings[0])) + return; + + GEM_BUG_ON(READ_ONCE(ve->context.inflight)); + if (!intel_engine_has_relative_mmio(engine)) + lrc_update_offsets(&ve->context, engine); + + /* + * Move the bound engine to the top of the list for + * future execution. We then kick this tasklet first + * before checking others, so that we preferentially + * reuse this set of bound registers. + */ + for (n = 1; n < ve->num_siblings; n++) { + if (ve->siblings[n] == engine) { + swap(ve->siblings[n], ve->siblings[0]); + break; + } + } +} + +static void defer_request(struct i915_request *rq, struct list_head * const pl) +{ + LIST_HEAD(list); + + /* + * We want to move the interrupted request to the back of + * the round-robin list (i.e. its priority level), but + * in doing so, we must then move all requests that were in + * flight and were waiting for the interrupted request to + * be run after it again. + */ + do { + struct i915_dependency *p; + + GEM_BUG_ON(i915_request_is_active(rq)); + list_move_tail(&rq->sched.link, pl); + + for_each_waiter(p, rq) { + struct i915_request *w = + container_of(p->waiter, typeof(*w), sched); + + if (p->flags & I915_DEPENDENCY_WEAK) + continue; + + /* Leave semaphores spinning on the other engines */ + if (w->engine != rq->engine) + continue; + + /* No waiter should start before its signaler */ + GEM_BUG_ON(i915_request_has_initial_breadcrumb(w) && + __i915_request_has_started(w) && + !__i915_request_is_complete(rq)); + + GEM_BUG_ON(i915_request_is_active(w)); + if (!i915_request_is_ready(w)) + continue; + + if (rq_prio(w) < rq_prio(rq)) + continue; + + GEM_BUG_ON(rq_prio(w) > rq_prio(rq)); + list_move_tail(&w->sched.link, &list); + } + + rq = list_first_entry_or_null(&list, typeof(*rq), sched.link); + } while (rq); +} + +static void defer_active(struct intel_engine_cs *engine) +{ + struct i915_request *rq; + + rq = __unwind_incomplete_requests(engine); + if (!rq) + return; + + defer_request(rq, i915_sched_lookup_priolist(engine, rq_prio(rq))); +} + +static bool +timeslice_yield(const struct intel_engine_execlists *el, + const struct i915_request *rq) +{ + /* + * Once bitten, forever smitten! + * + * If the active context ever busy-waited on a semaphore, + * it will be treated as a hog until the end of its timeslice (i.e. + * until it is scheduled out and replaced by a new submission, + * possibly even its own lite-restore). The HW only sends an interrupt + * on the first miss, and we do know if that semaphore has been + * signaled, or even if it is now stuck on another semaphore. Play + * safe, yield if it might be stuck -- it will be given a fresh + * timeslice in the near future. + */ + return rq->context->lrc.ccid == READ_ONCE(el->yield); +} + +static bool needs_timeslice(const struct intel_engine_cs *engine, + const struct i915_request *rq) +{ + if (!intel_engine_has_timeslices(engine)) + return false; + + /* If not currently active, or about to switch, wait for next event */ + if (!rq || __i915_request_is_complete(rq)) + return false; + + /* We do not need to start the timeslice until after the ACK */ + if (READ_ONCE(engine->execlists.pending[0])) + return false; + + /* If ELSP[1] is occupied, always check to see if worth slicing */ + if (!list_is_last_rcu(&rq->sched.link, &engine->active.requests)) { + ENGINE_TRACE(engine, "timeslice required for second inflight context\n"); + return true; + } + + /* Otherwise, ELSP[0] is by itself, but may be waiting in the queue */ + if (!RB_EMPTY_ROOT(&engine->execlists.queue.rb_root)) { + ENGINE_TRACE(engine, "timeslice required for queue\n"); + return true; + } + + if (!RB_EMPTY_ROOT(&engine->execlists.virtual.rb_root)) { + ENGINE_TRACE(engine, "timeslice required for virtual\n"); + return true; + } + + return false; +} + +static bool +timeslice_expired(struct intel_engine_cs *engine, const struct i915_request *rq) +{ + const struct intel_engine_execlists *el = &engine->execlists; + + if (i915_request_has_nopreempt(rq) && __i915_request_has_started(rq)) + return false; + + if (!needs_timeslice(engine, rq)) + return false; + + return timer_expired(&el->timer) || timeslice_yield(el, rq); +} + +static unsigned long timeslice(const struct intel_engine_cs *engine) +{ + return READ_ONCE(engine->props.timeslice_duration_ms); +} + +static void start_timeslice(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists *el = &engine->execlists; + unsigned long duration; + + /* Disable the timer if there is nothing to switch to */ + duration = 0; + if (needs_timeslice(engine, *el->active)) { + /* Avoid continually prolonging an active timeslice */ + if (timer_active(&el->timer)) { + /* + * If we just submitted a new ELSP after an old + * context, that context may have already consumed + * its timeslice, so recheck. + */ + if (!timer_pending(&el->timer)) + tasklet_hi_schedule(&el->tasklet); + return; + } + + duration = timeslice(engine); + } + + set_timer_ms(&el->timer, duration); +} + +static void record_preemption(struct intel_engine_execlists *execlists) +{ + (void)I915_SELFTEST_ONLY(execlists->preempt_hang.count++); +} + +static unsigned long active_preempt_timeout(struct intel_engine_cs *engine, + const struct i915_request *rq) +{ + if (!rq) + return 0; + + /* Force a fast reset for terminated contexts (ignoring sysfs!) */ + if (unlikely(intel_context_is_banned(rq->context))) + return 1; + + return READ_ONCE(engine->props.preempt_timeout_ms); +} + +static void set_preempt_timeout(struct intel_engine_cs *engine, + const struct i915_request *rq) +{ + if (!intel_engine_has_preempt_reset(engine)) + return; + + set_timer_ms(&engine->execlists.preempt, + active_preempt_timeout(engine, rq)); +} + +static bool completed(const struct i915_request *rq) +{ + if (i915_request_has_sentinel(rq)) + return false; + + return __i915_request_is_complete(rq); +} + +static void execlists_dequeue(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + struct i915_request **port = execlists->pending; + struct i915_request ** const last_port = port + execlists->port_mask; + struct i915_request *last, * const *active; + struct virtual_engine *ve; + struct rb_node *rb; + bool submit = false; + + /* + * Hardware submission is through 2 ports. Conceptually each port + * has a (RING_START, RING_HEAD, RING_TAIL) tuple. RING_START is + * static for a context, and unique to each, so we only execute + * requests belonging to a single context from each ring. RING_HEAD + * is maintained by the CS in the context image, it marks the place + * where it got up to last time, and through RING_TAIL we tell the CS + * where we want to execute up to this time. + * + * In this list the requests are in order of execution. Consecutive + * requests from the same context are adjacent in the ringbuffer. We + * can combine these requests into a single RING_TAIL update: + * + * RING_HEAD...req1...req2 + * ^- RING_TAIL + * since to execute req2 the CS must first execute req1. + * + * Our goal then is to point each port to the end of a consecutive + * sequence of requests as being the most optimal (fewest wake ups + * and context switches) submission. + */ + + spin_lock(&engine->active.lock); + + /* + * If the queue is higher priority than the last + * request in the currently active context, submit afresh. + * We will resubmit again afterwards in case we need to split + * the active context to interject the preemption request, + * i.e. we will retrigger preemption following the ack in case + * of trouble. + * + */ + active = execlists->active; + while ((last = *active) && completed(last)) + active++; + + if (last) { + if (need_preempt(engine, last)) { + ENGINE_TRACE(engine, + "preempting last=%llx:%lld, prio=%d, hint=%d\n", + last->fence.context, + last->fence.seqno, + last->sched.attr.priority, + execlists->queue_priority_hint); + record_preemption(execlists); + + /* + * Don't let the RING_HEAD advance past the breadcrumb + * as we unwind (and until we resubmit) so that we do + * not accidentally tell it to go backwards. + */ + ring_set_paused(engine, 1); + + /* + * Note that we have not stopped the GPU at this point, + * so we are unwinding the incomplete requests as they + * remain inflight and so by the time we do complete + * the preemption, some of the unwound requests may + * complete! + */ + __unwind_incomplete_requests(engine); + + last = NULL; + } else if (timeslice_expired(engine, last)) { + ENGINE_TRACE(engine, + "expired:%s last=%llx:%lld, prio=%d, hint=%d, yield?=%s\n", + yesno(timer_expired(&execlists->timer)), + last->fence.context, last->fence.seqno, + rq_prio(last), + execlists->queue_priority_hint, + yesno(timeslice_yield(execlists, last))); + + /* + * Consume this timeslice; ensure we start a new one. + * + * The timeslice expired, and we will unwind the + * running contexts and recompute the next ELSP. + * If that submit will be the same pair of contexts + * (due to dependency ordering), we will skip the + * submission. If we don't cancel the timer now, + * we will see that the timer has expired and + * reschedule the tasklet; continually until the + * next context switch or other preeemption event. + * + * Since we have decided to reschedule based on + * consumption of this timeslice, if we submit the + * same context again, grant it a full timeslice. + */ + cancel_timer(&execlists->timer); + ring_set_paused(engine, 1); + defer_active(engine); + + /* + * Unlike for preemption, if we rewind and continue + * executing the same context as previously active, + * the order of execution will remain the same and + * the tail will only advance. We do not need to + * force a full context restore, as a lite-restore + * is sufficient to resample the monotonic TAIL. + * + * If we switch to any other context, similarly we + * will not rewind TAIL of current context, and + * normal save/restore will preserve state and allow + * us to later continue executing the same request. + */ + last = NULL; + } else { + /* + * Otherwise if we already have a request pending + * for execution after the current one, we can + * just wait until the next CS event before + * queuing more. In either case we will force a + * lite-restore preemption event, but if we wait + * we hopefully coalesce several updates into a single + * submission. + */ + if (active[1]) { + /* + * Even if ELSP[1] is occupied and not worthy + * of timeslices, our queue might be. + */ + spin_unlock(&engine->active.lock); + return; + } + } + } + + /* XXX virtual is always taking precedence */ + while ((ve = first_virtual_engine(engine))) { + struct i915_request *rq; + + spin_lock(&ve->base.active.lock); + + rq = ve->request; + if (unlikely(!virtual_matches(ve, rq, engine))) + goto unlock; /* lost the race to a sibling */ + + GEM_BUG_ON(rq->engine != &ve->base); + GEM_BUG_ON(rq->context != &ve->context); + + if (unlikely(rq_prio(rq) < queue_prio(execlists))) { + spin_unlock(&ve->base.active.lock); + break; + } + + if (last && !can_merge_rq(last, rq)) { + spin_unlock(&ve->base.active.lock); + spin_unlock(&engine->active.lock); + return; /* leave this for another sibling */ + } + + ENGINE_TRACE(engine, + "virtual rq=%llx:%lld%s, new engine? %s\n", + rq->fence.context, + rq->fence.seqno, + __i915_request_is_complete(rq) ? "!" : + __i915_request_has_started(rq) ? "*" : + "", + yesno(engine != ve->siblings[0])); + + WRITE_ONCE(ve->request, NULL); + WRITE_ONCE(ve->base.execlists.queue_priority_hint, INT_MIN); + + rb = &ve->nodes[engine->id].rb; + rb_erase_cached(rb, &execlists->virtual); + RB_CLEAR_NODE(rb); + + GEM_BUG_ON(!(rq->execution_mask & engine->mask)); + WRITE_ONCE(rq->engine, engine); + + if (__i915_request_submit(rq)) { + /* + * Only after we confirm that we will submit + * this request (i.e. it has not already + * completed), do we want to update the context. + * + * This serves two purposes. It avoids + * unnecessary work if we are resubmitting an + * already completed request after timeslicing. + * But more importantly, it prevents us altering + * ve->siblings[] on an idle context, where + * we may be using ve->siblings[] in + * virtual_context_enter / virtual_context_exit. + */ + virtual_xfer_context(ve, engine); + GEM_BUG_ON(ve->siblings[0] != engine); + + submit = true; + last = rq; + } + + i915_request_put(rq); +unlock: + spin_unlock(&ve->base.active.lock); + + /* + * Hmm, we have a bunch of virtual engine requests, + * but the first one was already completed (thanks + * preempt-to-busy!). Keep looking at the veng queue + * until we have no more relevant requests (i.e. + * the normal submit queue has higher priority). + */ + if (submit) + break; + } + + while ((rb = rb_first_cached(&execlists->queue))) { + struct i915_priolist *p = to_priolist(rb); + struct i915_request *rq, *rn; + int i; + + priolist_for_each_request_consume(rq, rn, p, i) { + bool merge = true; + + /* + * Can we combine this request with the current port? + * It has to be the same context/ringbuffer and not + * have any exceptions (e.g. GVT saying never to + * combine contexts). + * + * If we can combine the requests, we can execute both + * by updating the RING_TAIL to point to the end of the + * second request, and so we never need to tell the + * hardware about the first. + */ + if (last && !can_merge_rq(last, rq)) { + /* + * If we are on the second port and cannot + * combine this request with the last, then we + * are done. + */ + if (port == last_port) + goto done; + + /* + * We must not populate both ELSP[] with the + * same LRCA, i.e. we must submit 2 different + * contexts if we submit 2 ELSP. + */ + if (last->context == rq->context) + goto done; + + if (i915_request_has_sentinel(last)) + goto done; + + /* + * We avoid submitting virtual requests into + * the secondary ports so that we can migrate + * the request immediately to another engine + * rather than wait for the primary request. + */ + if (rq->execution_mask != engine->mask) + goto done; + + /* + * If GVT overrides us we only ever submit + * port[0], leaving port[1] empty. Note that we + * also have to be careful that we don't queue + * the same context (even though a different + * request) to the second port. + */ + if (ctx_single_port_submission(last->context) || + ctx_single_port_submission(rq->context)) + goto done; + + merge = false; + } + + if (__i915_request_submit(rq)) { + if (!merge) { + *port++ = i915_request_get(last); + last = NULL; + } + + GEM_BUG_ON(last && + !can_merge_ctx(last->context, + rq->context)); + GEM_BUG_ON(last && + i915_seqno_passed(last->fence.seqno, + rq->fence.seqno)); + + submit = true; + last = rq; + } + } + + rb_erase_cached(&p->node, &execlists->queue); + i915_priolist_free(p); + } +done: + *port++ = i915_request_get(last); + + /* + * Here be a bit of magic! Or sleight-of-hand, whichever you prefer. + * + * We choose the priority hint such that if we add a request of greater + * priority than this, we kick the submission tasklet to decide on + * the right order of submitting the requests to hardware. We must + * also be prepared to reorder requests as they are in-flight on the + * HW. We derive the priority hint then as the first "hole" in + * the HW submission ports and if there are no available slots, + * the priority of the lowest executing request, i.e. last. + * + * When we do receive a higher priority request ready to run from the + * user, see queue_request(), the priority hint is bumped to that + * request triggering preemption on the next dequeue (or subsequent + * interrupt for secondary ports). + */ + execlists->queue_priority_hint = queue_prio(execlists); + spin_unlock(&engine->active.lock); + + /* + * We can skip poking the HW if we ended up with exactly the same set + * of requests as currently running, e.g. trying to timeslice a pair + * of ordered contexts. + */ + if (submit && + memcmp(active, + execlists->pending, + (port - execlists->pending) * sizeof(*port))) { + *port = NULL; + while (port-- != execlists->pending) + execlists_schedule_in(*port, port - execlists->pending); + + WRITE_ONCE(execlists->yield, -1); + set_preempt_timeout(engine, *active); + execlists_submit_ports(engine); + } else { + ring_set_paused(engine, 0); + while (port-- != execlists->pending) + i915_request_put(*port); + *execlists->pending = NULL; + } +} + +static void execlists_dequeue_irq(struct intel_engine_cs *engine) +{ + local_irq_disable(); /* Suspend interrupts across request submission */ + execlists_dequeue(engine); + local_irq_enable(); /* flush irq_work (e.g. breadcrumb enabling) */ +} + +static void clear_ports(struct i915_request **ports, int count) +{ + memset_p((void **)ports, NULL, count); +} + +static void +copy_ports(struct i915_request **dst, struct i915_request **src, int count) +{ + /* A memcpy_p() would be very useful here! */ + while (count--) + WRITE_ONCE(*dst++, *src++); /* avoid write tearing */ +} + +static struct i915_request ** +cancel_port_requests(struct intel_engine_execlists * const execlists, + struct i915_request **inactive) +{ + struct i915_request * const *port; + + for (port = execlists->pending; *port; port++) + *inactive++ = *port; + clear_ports(execlists->pending, ARRAY_SIZE(execlists->pending)); + + /* Mark the end of active before we overwrite *active */ + for (port = xchg(&execlists->active, execlists->pending); *port; port++) + *inactive++ = *port; + clear_ports(execlists->inflight, ARRAY_SIZE(execlists->inflight)); + + smp_wmb(); /* complete the seqlock for execlists_active() */ + WRITE_ONCE(execlists->active, execlists->inflight); + + /* Having cancelled all outstanding process_csb(), stop their timers */ + GEM_BUG_ON(execlists->pending[0]); + cancel_timer(&execlists->timer); + cancel_timer(&execlists->preempt); + + return inactive; +} + +static void invalidate_csb_entries(const u64 *first, const u64 *last) +{ + clflush((void *)first); + clflush((void *)last); +} + +/* + * Starting with Gen12, the status has a new format: + * + * bit 0: switched to new queue + * bit 1: reserved + * bit 2: semaphore wait mode (poll or signal), only valid when + * switch detail is set to "wait on semaphore" + * bits 3-5: engine class + * bits 6-11: engine instance + * bits 12-14: reserved + * bits 15-25: sw context id of the lrc the GT switched to + * bits 26-31: sw counter of the lrc the GT switched to + * bits 32-35: context switch detail + * - 0: ctx complete + * - 1: wait on sync flip + * - 2: wait on vblank + * - 3: wait on scanline + * - 4: wait on semaphore + * - 5: context preempted (not on SEMAPHORE_WAIT or + * WAIT_FOR_EVENT) + * bit 36: reserved + * bits 37-43: wait detail (for switch detail 1 to 4) + * bits 44-46: reserved + * bits 47-57: sw context id of the lrc the GT switched away from + * bits 58-63: sw counter of the lrc the GT switched away from + */ +static bool gen12_csb_parse(const u64 csb) +{ + bool ctx_away_valid = GEN12_CSB_CTX_VALID(upper_32_bits(csb)); + bool new_queue = + lower_32_bits(csb) & GEN12_CTX_STATUS_SWITCHED_TO_NEW_QUEUE; + + /* + * The context switch detail is not guaranteed to be 5 when a preemption + * occurs, so we can't just check for that. The check below works for + * all the cases we care about, including preemptions of WAIT + * instructions and lite-restore. Preempt-to-idle via the CTRL register + * would require some extra handling, but we don't support that. + */ + if (!ctx_away_valid || new_queue) { + GEM_BUG_ON(!GEN12_CSB_CTX_VALID(lower_32_bits(csb))); + return true; + } + + /* + * switch detail = 5 is covered by the case above and we do not expect a + * context switch on an unsuccessful wait instruction since we always + * use polling mode. + */ + GEM_BUG_ON(GEN12_CTX_SWITCH_DETAIL(upper_32_bits(csb))); + return false; +} + +static bool gen8_csb_parse(const u64 csb) +{ + return csb & (GEN8_CTX_STATUS_IDLE_ACTIVE | GEN8_CTX_STATUS_PREEMPTED); +} + +static noinline u64 +wa_csb_read(const struct intel_engine_cs *engine, u64 * const csb) +{ + u64 entry; + + /* + * Reading from the HWSP has one particular advantage: we can detect + * a stale entry. Since the write into HWSP is broken, we have no reason + * to trust the HW at all, the mmio entry may equally be unordered, so + * we prefer the path that is self-checking and as a last resort, + * return the mmio value. + * + * tgl,dg1:HSDES#22011327657 + */ + preempt_disable(); + if (wait_for_atomic_us((entry = READ_ONCE(*csb)) != -1, 10)) { + int idx = csb - engine->execlists.csb_status; + int status; + + status = GEN8_EXECLISTS_STATUS_BUF; + if (idx >= 6) { + status = GEN11_EXECLISTS_STATUS_BUF2; + idx -= 6; + } + status += sizeof(u64) * idx; + + entry = intel_uncore_read64(engine->uncore, + _MMIO(engine->mmio_base + status)); + } + preempt_enable(); + + return entry; +} + +static u64 csb_read(const struct intel_engine_cs *engine, u64 * const csb) +{ + u64 entry = READ_ONCE(*csb); + + /* + * Unfortunately, the GPU does not always serialise its write + * of the CSB entries before its write of the CSB pointer, at least + * from the perspective of the CPU, using what is known as a Global + * Observation Point. We may read a new CSB tail pointer, but then + * read the stale CSB entries, causing us to misinterpret the + * context-switch events, and eventually declare the GPU hung. + * + * icl:HSDES#1806554093 + * tgl:HSDES#22011248461 + */ + if (unlikely(entry == -1)) + entry = wa_csb_read(engine, csb); + + /* Consume this entry so that we can spot its future reuse. */ + WRITE_ONCE(*csb, -1); + + /* ELSP is an implicit wmb() before the GPU wraps and overwrites csb */ + return entry; +} + +static void new_timeslice(struct intel_engine_execlists *el) +{ + /* By cancelling, we will start afresh in start_timeslice() */ + cancel_timer(&el->timer); +} + +static struct i915_request ** +process_csb(struct intel_engine_cs *engine, struct i915_request **inactive) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + u64 * const buf = execlists->csb_status; + const u8 num_entries = execlists->csb_size; + struct i915_request **prev; + u8 head, tail; + + /* + * As we modify our execlists state tracking we require exclusive + * access. Either we are inside the tasklet, or the tasklet is disabled + * and we assume that is only inside the reset paths and so serialised. + */ + GEM_BUG_ON(!tasklet_is_locked(&execlists->tasklet) && + !reset_in_progress(execlists)); + GEM_BUG_ON(!intel_engine_in_execlists_submission_mode(engine)); + + /* + * Note that csb_write, csb_status may be either in HWSP or mmio. + * When reading from the csb_write mmio register, we have to be + * careful to only use the GEN8_CSB_WRITE_PTR portion, which is + * the low 4bits. As it happens we know the next 4bits are always + * zero and so we can simply masked off the low u8 of the register + * and treat it identically to reading from the HWSP (without having + * to use explicit shifting and masking, and probably bifurcating + * the code to handle the legacy mmio read). + */ + head = execlists->csb_head; + tail = READ_ONCE(*execlists->csb_write); + if (unlikely(head == tail)) + return inactive; + + /* + * We will consume all events from HW, or at least pretend to. + * + * The sequence of events from the HW is deterministic, and derived + * from our writes to the ELSP, with a smidgen of variability for + * the arrival of the asynchronous requests wrt to the inflight + * execution. If the HW sends an event that does not correspond with + * the one we are expecting, we have to abandon all hope as we lose + * all tracking of what the engine is actually executing. We will + * only detect we are out of sequence with the HW when we get an + * 'impossible' event because we have already drained our own + * preemption/promotion queue. If this occurs, we know that we likely + * lost track of execution earlier and must unwind and restart, the + * simplest way is by stop processing the event queue and force the + * engine to reset. + */ + execlists->csb_head = tail; + ENGINE_TRACE(engine, "cs-irq head=%d, tail=%d\n", head, tail); + + /* + * Hopefully paired with a wmb() in HW! + * + * We must complete the read of the write pointer before any reads + * from the CSB, so that we do not see stale values. Without an rmb + * (lfence) the HW may speculatively perform the CSB[] reads *before* + * we perform the READ_ONCE(*csb_write). + */ + rmb(); + + /* Remember who was last running under the timer */ + prev = inactive; + *prev = NULL; + + do { + bool promote; + u64 csb; + + if (++head == num_entries) + head = 0; + + /* + * We are flying near dragons again. + * + * We hold a reference to the request in execlist_port[] + * but no more than that. We are operating in softirq + * context and so cannot hold any mutex or sleep. That + * prevents us stopping the requests we are processing + * in port[] from being retired simultaneously (the + * breadcrumb will be complete before we see the + * context-switch). As we only hold the reference to the + * request, any pointer chasing underneath the request + * is subject to a potential use-after-free. Thus we + * store all of the bookkeeping within port[] as + * required, and avoid using unguarded pointers beneath + * request itself. The same applies to the atomic + * status notifier. + */ + + csb = csb_read(engine, buf + head); + ENGINE_TRACE(engine, "csb[%d]: status=0x%08x:0x%08x\n", + head, upper_32_bits(csb), lower_32_bits(csb)); + + if (INTEL_GEN(engine->i915) >= 12) + promote = gen12_csb_parse(csb); + else + promote = gen8_csb_parse(csb); + if (promote) { + struct i915_request * const *old = execlists->active; + + if (GEM_WARN_ON(!*execlists->pending)) { + execlists->error_interrupt |= ERROR_CSB; + break; + } + + ring_set_paused(engine, 0); + + /* Point active to the new ELSP; prevent overwriting */ + WRITE_ONCE(execlists->active, execlists->pending); + smp_wmb(); /* notify execlists_active() */ + + /* cancel old inflight, prepare for switch */ + trace_ports(execlists, "preempted", old); + while (*old) + *inactive++ = *old++; + + /* switch pending to inflight */ + GEM_BUG_ON(!assert_pending_valid(execlists, "promote")); + copy_ports(execlists->inflight, + execlists->pending, + execlists_num_ports(execlists)); + smp_wmb(); /* complete the seqlock */ + WRITE_ONCE(execlists->active, execlists->inflight); + + /* XXX Magic delay for tgl */ + ENGINE_POSTING_READ(engine, RING_CONTEXT_STATUS_PTR); + + WRITE_ONCE(execlists->pending[0], NULL); + } else { + if (GEM_WARN_ON(!*execlists->active)) { + execlists->error_interrupt |= ERROR_CSB; + break; + } + + /* port0 completed, advanced to port1 */ + trace_ports(execlists, "completed", execlists->active); + + /* + * We rely on the hardware being strongly + * ordered, that the breadcrumb write is + * coherent (visible from the CPU) before the + * user interrupt is processed. One might assume + * that the breadcrumb write being before the + * user interrupt and the CS event for the context + * switch would therefore be before the CS event + * itself... + */ + if (GEM_SHOW_DEBUG() && + !__i915_request_is_complete(*execlists->active)) { + struct i915_request *rq = *execlists->active; + const u32 *regs __maybe_unused = + rq->context->lrc_reg_state; + + ENGINE_TRACE(engine, + "context completed before request!\n"); + ENGINE_TRACE(engine, + "ring:{start:0x%08x, head:%04x, tail:%04x, ctl:%08x, mode:%08x}\n", + ENGINE_READ(engine, RING_START), + ENGINE_READ(engine, RING_HEAD) & HEAD_ADDR, + ENGINE_READ(engine, RING_TAIL) & TAIL_ADDR, + ENGINE_READ(engine, RING_CTL), + ENGINE_READ(engine, RING_MI_MODE)); + ENGINE_TRACE(engine, + "rq:{start:%08x, head:%04x, tail:%04x, seqno:%llx:%d, hwsp:%d}, ", + i915_ggtt_offset(rq->ring->vma), + rq->head, rq->tail, + rq->fence.context, + lower_32_bits(rq->fence.seqno), + hwsp_seqno(rq)); + ENGINE_TRACE(engine, + "ctx:{start:%08x, head:%04x, tail:%04x}, ", + regs[CTX_RING_START], + regs[CTX_RING_HEAD], + regs[CTX_RING_TAIL]); + } + + *inactive++ = *execlists->active++; + + GEM_BUG_ON(execlists->active - execlists->inflight > + execlists_num_ports(execlists)); + } + } while (head != tail); + + /* + * Gen11 has proven to fail wrt global observation point between + * entry and tail update, failing on the ordering and thus + * we see an old entry in the context status buffer. + * + * Forcibly evict out entries for the next gpu csb update, + * to increase the odds that we get a fresh entries with non + * working hardware. The cost for doing so comes out mostly with + * the wash as hardware, working or not, will need to do the + * invalidation before. + */ + invalidate_csb_entries(&buf[0], &buf[num_entries - 1]); + + /* + * We assume that any event reflects a change in context flow + * and merits a fresh timeslice. We reinstall the timer after + * inspecting the queue to see if we need to resumbit. + */ + if (*prev != *execlists->active) /* elide lite-restores */ + new_timeslice(execlists); + + return inactive; +} + +static void post_process_csb(struct i915_request **port, + struct i915_request **last) +{ + while (port != last) + execlists_schedule_out(*port++); +} + +static void __execlists_hold(struct i915_request *rq) +{ + LIST_HEAD(list); + + do { + struct i915_dependency *p; + + if (i915_request_is_active(rq)) + __i915_request_unsubmit(rq); + + clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags); + list_move_tail(&rq->sched.link, &rq->engine->active.hold); + i915_request_set_hold(rq); + RQ_TRACE(rq, "on hold\n"); + + for_each_waiter(p, rq) { + struct i915_request *w = + container_of(p->waiter, typeof(*w), sched); + + if (p->flags & I915_DEPENDENCY_WEAK) + continue; + + /* Leave semaphores spinning on the other engines */ + if (w->engine != rq->engine) + continue; + + if (!i915_request_is_ready(w)) + continue; + + if (__i915_request_is_complete(w)) + continue; + + if (i915_request_on_hold(w)) + continue; + + list_move_tail(&w->sched.link, &list); + } + + rq = list_first_entry_or_null(&list, typeof(*rq), sched.link); + } while (rq); +} + +static bool execlists_hold(struct intel_engine_cs *engine, + struct i915_request *rq) +{ + if (i915_request_on_hold(rq)) + return false; + + spin_lock_irq(&engine->active.lock); + + if (__i915_request_is_complete(rq)) { /* too late! */ + rq = NULL; + goto unlock; + } + + /* + * Transfer this request onto the hold queue to prevent it + * being resumbitted to HW (and potentially completed) before we have + * released it. Since we may have already submitted following + * requests, we need to remove those as well. + */ + GEM_BUG_ON(i915_request_on_hold(rq)); + GEM_BUG_ON(rq->engine != engine); + __execlists_hold(rq); + GEM_BUG_ON(list_empty(&engine->active.hold)); + +unlock: + spin_unlock_irq(&engine->active.lock); + return rq; +} + +static bool hold_request(const struct i915_request *rq) +{ + struct i915_dependency *p; + bool result = false; + + /* + * If one of our ancestors is on hold, we must also be on hold, + * otherwise we will bypass it and execute before it. + */ + rcu_read_lock(); + for_each_signaler(p, rq) { + const struct i915_request *s = + container_of(p->signaler, typeof(*s), sched); + + if (s->engine != rq->engine) + continue; + + result = i915_request_on_hold(s); + if (result) + break; + } + rcu_read_unlock(); + + return result; +} + +static void __execlists_unhold(struct i915_request *rq) +{ + LIST_HEAD(list); + + do { + struct i915_dependency *p; + + RQ_TRACE(rq, "hold release\n"); + + GEM_BUG_ON(!i915_request_on_hold(rq)); + GEM_BUG_ON(!i915_sw_fence_signaled(&rq->submit)); + + i915_request_clear_hold(rq); + list_move_tail(&rq->sched.link, + i915_sched_lookup_priolist(rq->engine, + rq_prio(rq))); + set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags); + + /* Also release any children on this engine that are ready */ + for_each_waiter(p, rq) { + struct i915_request *w = + container_of(p->waiter, typeof(*w), sched); + + if (p->flags & I915_DEPENDENCY_WEAK) + continue; + + /* Propagate any change in error status */ + if (rq->fence.error) + i915_request_set_error_once(w, rq->fence.error); + + if (w->engine != rq->engine) + continue; + + if (!i915_request_on_hold(w)) + continue; + + /* Check that no other parents are also on hold */ + if (hold_request(w)) + continue; + + list_move_tail(&w->sched.link, &list); + } + + rq = list_first_entry_or_null(&list, typeof(*rq), sched.link); + } while (rq); +} + +static void execlists_unhold(struct intel_engine_cs *engine, + struct i915_request *rq) +{ + spin_lock_irq(&engine->active.lock); + + /* + * Move this request back to the priority queue, and all of its + * children and grandchildren that were suspended along with it. + */ + __execlists_unhold(rq); + + if (rq_prio(rq) > engine->execlists.queue_priority_hint) { + engine->execlists.queue_priority_hint = rq_prio(rq); + tasklet_hi_schedule(&engine->execlists.tasklet); + } + + spin_unlock_irq(&engine->active.lock); +} + +struct execlists_capture { + struct work_struct work; + struct i915_request *rq; + struct i915_gpu_coredump *error; +}; + +static void execlists_capture_work(struct work_struct *work) +{ + struct execlists_capture *cap = container_of(work, typeof(*cap), work); + const gfp_t gfp = GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN; + struct intel_engine_cs *engine = cap->rq->engine; + struct intel_gt_coredump *gt = cap->error->gt; + struct intel_engine_capture_vma *vma; + + /* Compress all the objects attached to the request, slow! */ + vma = intel_engine_coredump_add_request(gt->engine, cap->rq, gfp); + if (vma) { + struct i915_vma_compress *compress = + i915_vma_capture_prepare(gt); + + intel_engine_coredump_add_vma(gt->engine, vma, compress); + i915_vma_capture_finish(gt, compress); + } + + gt->simulated = gt->engine->simulated; + cap->error->simulated = gt->simulated; + + /* Publish the error state, and announce it to the world */ + i915_error_state_store(cap->error); + i915_gpu_coredump_put(cap->error); + + /* Return this request and all that depend upon it for signaling */ + execlists_unhold(engine, cap->rq); + i915_request_put(cap->rq); + + kfree(cap); +} + +static struct execlists_capture *capture_regs(struct intel_engine_cs *engine) +{ + const gfp_t gfp = GFP_ATOMIC | __GFP_NOWARN; + struct execlists_capture *cap; + + cap = kmalloc(sizeof(*cap), gfp); + if (!cap) + return NULL; + + cap->error = i915_gpu_coredump_alloc(engine->i915, gfp); + if (!cap->error) + goto err_cap; + + cap->error->gt = intel_gt_coredump_alloc(engine->gt, gfp); + if (!cap->error->gt) + goto err_gpu; + + cap->error->gt->engine = intel_engine_coredump_alloc(engine, gfp); + if (!cap->error->gt->engine) + goto err_gt; + + cap->error->gt->engine->hung = true; + + return cap; + +err_gt: + kfree(cap->error->gt); +err_gpu: + kfree(cap->error); +err_cap: + kfree(cap); + return NULL; +} + +static struct i915_request * +active_context(struct intel_engine_cs *engine, u32 ccid) +{ + const struct intel_engine_execlists * const el = &engine->execlists; + struct i915_request * const *port, *rq; + + /* + * Use the most recent result from process_csb(), but just in case + * we trigger an error (via interrupt) before the first CS event has + * been written, peek at the next submission. + */ + + for (port = el->active; (rq = *port); port++) { + if (rq->context->lrc.ccid == ccid) { + ENGINE_TRACE(engine, + "ccid:%x found at active:%zd\n", + ccid, port - el->active); + return rq; + } + } + + for (port = el->pending; (rq = *port); port++) { + if (rq->context->lrc.ccid == ccid) { + ENGINE_TRACE(engine, + "ccid:%x found at pending:%zd\n", + ccid, port - el->pending); + return rq; + } + } + + ENGINE_TRACE(engine, "ccid:%x not found\n", ccid); + return NULL; +} + +static u32 active_ccid(struct intel_engine_cs *engine) +{ + return ENGINE_READ_FW(engine, RING_EXECLIST_STATUS_HI); +} + +static void execlists_capture(struct intel_engine_cs *engine) +{ + struct execlists_capture *cap; + + if (!IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)) + return; + + /* + * We need to _quickly_ capture the engine state before we reset. + * We are inside an atomic section (softirq) here and we are delaying + * the forced preemption event. + */ + cap = capture_regs(engine); + if (!cap) + return; + + spin_lock_irq(&engine->active.lock); + cap->rq = active_context(engine, active_ccid(engine)); + if (cap->rq) { + cap->rq = active_request(cap->rq->context->timeline, cap->rq); + cap->rq = i915_request_get_rcu(cap->rq); + } + spin_unlock_irq(&engine->active.lock); + if (!cap->rq) + goto err_free; + + /* + * Remove the request from the execlists queue, and take ownership + * of the request. We pass it to our worker who will _slowly_ compress + * all the pages the _user_ requested for debugging their batch, after + * which we return it to the queue for signaling. + * + * By removing them from the execlists queue, we also remove the + * requests from being processed by __unwind_incomplete_requests() + * during the intel_engine_reset(), and so they will *not* be replayed + * afterwards. + * + * Note that because we have not yet reset the engine at this point, + * it is possible for the request that we have identified as being + * guilty, did in fact complete and we will then hit an arbitration + * point allowing the outstanding preemption to succeed. The likelihood + * of that is very low (as capturing of the engine registers should be + * fast enough to run inside an irq-off atomic section!), so we will + * simply hold that request accountable for being non-preemptible + * long enough to force the reset. + */ + if (!execlists_hold(engine, cap->rq)) + goto err_rq; + + INIT_WORK(&cap->work, execlists_capture_work); + schedule_work(&cap->work); + return; + +err_rq: + i915_request_put(cap->rq); +err_free: + i915_gpu_coredump_put(cap->error); + kfree(cap); +} + +static void execlists_reset(struct intel_engine_cs *engine, const char *msg) +{ + const unsigned int bit = I915_RESET_ENGINE + engine->id; + unsigned long *lock = &engine->gt->reset.flags; + + if (!intel_has_reset_engine(engine->gt)) + return; + + if (test_and_set_bit(bit, lock)) + return; + + ENGINE_TRACE(engine, "reset for %s\n", msg); + + /* Mark this tasklet as disabled to avoid waiting for it to complete */ + tasklet_disable_nosync(&engine->execlists.tasklet); + + ring_set_paused(engine, 1); /* Freeze the current request in place */ + execlists_capture(engine); + intel_engine_reset(engine, msg); + + tasklet_enable(&engine->execlists.tasklet); + clear_and_wake_up_bit(bit, lock); +} + +static bool preempt_timeout(const struct intel_engine_cs *const engine) +{ + const struct timer_list *t = &engine->execlists.preempt; + + if (!CONFIG_DRM_I915_PREEMPT_TIMEOUT) + return false; + + if (!timer_expired(t)) + return false; + + return engine->execlists.pending[0]; +} + +/* + * Check the unread Context Status Buffers and manage the submission of new + * contexts to the ELSP accordingly. + */ +static void execlists_submission_tasklet(unsigned long data) +{ + struct intel_engine_cs * const engine = (struct intel_engine_cs *)data; + struct i915_request *post[2 * EXECLIST_MAX_PORTS]; + struct i915_request **inactive; + + rcu_read_lock(); + inactive = process_csb(engine, post); + GEM_BUG_ON(inactive - post > ARRAY_SIZE(post)); + + if (unlikely(preempt_timeout(engine))) { + cancel_timer(&engine->execlists.preempt); + engine->execlists.error_interrupt |= ERROR_PREEMPT; + } + + if (unlikely(READ_ONCE(engine->execlists.error_interrupt))) { + const char *msg; + + /* Generate the error message in priority wrt to the user! */ + if (engine->execlists.error_interrupt & GENMASK(15, 0)) + msg = "CS error"; /* thrown by a user payload */ + else if (engine->execlists.error_interrupt & ERROR_CSB) + msg = "invalid CSB event"; + else if (engine->execlists.error_interrupt & ERROR_PREEMPT) + msg = "preemption time out"; + else + msg = "internal error"; + + engine->execlists.error_interrupt = 0; + execlists_reset(engine, msg); + } + + if (!engine->execlists.pending[0]) { + execlists_dequeue_irq(engine); + start_timeslice(engine); + } + + post_process_csb(post, inactive); + rcu_read_unlock(); +} + +static void __execlists_kick(struct intel_engine_execlists *execlists) +{ + /* Kick the tasklet for some interrupt coalescing and reset handling */ + tasklet_hi_schedule(&execlists->tasklet); +} + +#define execlists_kick(t, member) \ + __execlists_kick(container_of(t, struct intel_engine_execlists, member)) + +static void execlists_timeslice(struct timer_list *timer) +{ + execlists_kick(timer, timer); +} + +static void execlists_preempt(struct timer_list *timer) +{ + execlists_kick(timer, preempt); +} + +static void queue_request(struct intel_engine_cs *engine, + struct i915_request *rq) +{ + GEM_BUG_ON(!list_empty(&rq->sched.link)); + list_add_tail(&rq->sched.link, + i915_sched_lookup_priolist(engine, rq_prio(rq))); + set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags); +} + +static bool submit_queue(struct intel_engine_cs *engine, + const struct i915_request *rq) +{ + struct intel_engine_execlists *execlists = &engine->execlists; + + if (rq_prio(rq) <= execlists->queue_priority_hint) + return false; + + execlists->queue_priority_hint = rq_prio(rq); + return true; +} + +static bool ancestor_on_hold(const struct intel_engine_cs *engine, + const struct i915_request *rq) +{ + GEM_BUG_ON(i915_request_on_hold(rq)); + return !list_empty(&engine->active.hold) && hold_request(rq); +} + +static void execlists_submit_request(struct i915_request *request) +{ + struct intel_engine_cs *engine = request->engine; + unsigned long flags; + + /* Will be called from irq-context when using foreign fences. */ + spin_lock_irqsave(&engine->active.lock, flags); + + if (unlikely(ancestor_on_hold(engine, request))) { + RQ_TRACE(request, "ancestor on hold\n"); + list_add_tail(&request->sched.link, &engine->active.hold); + i915_request_set_hold(request); + } else { + queue_request(engine, request); + + GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root)); + GEM_BUG_ON(list_empty(&request->sched.link)); + + if (submit_queue(engine, request)) + __execlists_kick(&engine->execlists); + } + + spin_unlock_irqrestore(&engine->active.lock, flags); +} + +static int execlists_context_pre_pin(struct intel_context *ce, + struct i915_gem_ww_ctx *ww, + void **vaddr) +{ + return lrc_pre_pin(ce, ce->engine, ww, vaddr); +} + +static int execlists_context_pin(struct intel_context *ce, void *vaddr) +{ + return lrc_pin(ce, ce->engine, vaddr); +} + +static int execlists_context_alloc(struct intel_context *ce) +{ + return lrc_alloc(ce, ce->engine); +} + +static const struct intel_context_ops execlists_context_ops = { + .flags = COPS_HAS_INFLIGHT, + + .alloc = execlists_context_alloc, + + .pre_pin = execlists_context_pre_pin, + .pin = execlists_context_pin, + .unpin = lrc_unpin, + .post_unpin = lrc_post_unpin, + + .enter = intel_context_enter_engine, + .exit = intel_context_exit_engine, + + .reset = lrc_reset, + .destroy = lrc_destroy, +}; + +static int emit_pdps(struct i915_request *rq) +{ + const struct intel_engine_cs * const engine = rq->engine; + struct i915_ppgtt * const ppgtt = i915_vm_to_ppgtt(rq->context->vm); + int err, i; + u32 *cs; + + GEM_BUG_ON(intel_vgpu_active(rq->engine->i915)); + + /* + * Beware ye of the dragons, this sequence is magic! + * + * Small changes to this sequence can cause anything from + * GPU hangs to forcewake errors and machine lockups! + */ + + cs = intel_ring_begin(rq, 2); + if (IS_ERR(cs)) + return PTR_ERR(cs); + + *cs++ = MI_ARB_ON_OFF | MI_ARB_DISABLE; + *cs++ = MI_NOOP; + intel_ring_advance(rq, cs); + + /* Flush any residual operations from the context load */ + err = engine->emit_flush(rq, EMIT_FLUSH); + if (err) + return err; + + /* Magic required to prevent forcewake errors! */ + err = engine->emit_flush(rq, EMIT_INVALIDATE); + if (err) + return err; + + cs = intel_ring_begin(rq, 4 * GEN8_3LVL_PDPES + 2); + if (IS_ERR(cs)) + return PTR_ERR(cs); + + /* Ensure the LRI have landed before we invalidate & continue */ + *cs++ = MI_LOAD_REGISTER_IMM(2 * GEN8_3LVL_PDPES) | MI_LRI_FORCE_POSTED; + for (i = GEN8_3LVL_PDPES; i--; ) { + const dma_addr_t pd_daddr = i915_page_dir_dma_addr(ppgtt, i); + u32 base = engine->mmio_base; + + *cs++ = i915_mmio_reg_offset(GEN8_RING_PDP_UDW(base, i)); + *cs++ = upper_32_bits(pd_daddr); + *cs++ = i915_mmio_reg_offset(GEN8_RING_PDP_LDW(base, i)); + *cs++ = lower_32_bits(pd_daddr); + } + *cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE; + intel_ring_advance(rq, cs); + + intel_ring_advance(rq, cs); + + return 0; +} + +static int execlists_request_alloc(struct i915_request *request) +{ + int ret; + + GEM_BUG_ON(!intel_context_is_pinned(request->context)); + + /* + * Flush enough space to reduce the likelihood of waiting after + * we start building the request - in which case we will just + * have to repeat work. + */ + request->reserved_space += EXECLISTS_REQUEST_SIZE; + + /* + * Note that after this point, we have committed to using + * this request as it is being used to both track the + * state of engine initialisation and liveness of the + * golden renderstate above. Think twice before you try + * to cancel/unwind this request now. + */ + + if (!i915_vm_is_4lvl(request->context->vm)) { + ret = emit_pdps(request); + if (ret) + return ret; + } + + /* Unconditionally invalidate GPU caches and TLBs. */ + ret = request->engine->emit_flush(request, EMIT_INVALIDATE); + if (ret) + return ret; + + request->reserved_space -= EXECLISTS_REQUEST_SIZE; + return 0; +} + +static void reset_csb_pointers(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + const unsigned int reset_value = execlists->csb_size - 1; + + ring_set_paused(engine, 0); + + /* + * Sometimes Icelake forgets to reset its pointers on a GPU reset. + * Bludgeon them with a mmio update to be sure. + */ + ENGINE_WRITE(engine, RING_CONTEXT_STATUS_PTR, + 0xffff << 16 | reset_value << 8 | reset_value); + ENGINE_POSTING_READ(engine, RING_CONTEXT_STATUS_PTR); + + /* + * After a reset, the HW starts writing into CSB entry [0]. We + * therefore have to set our HEAD pointer back one entry so that + * the *first* entry we check is entry 0. To complicate this further, + * as we don't wait for the first interrupt after reset, we have to + * fake the HW write to point back to the last entry so that our + * inline comparison of our cached head position against the last HW + * write works even before the first interrupt. + */ + execlists->csb_head = reset_value; + WRITE_ONCE(*execlists->csb_write, reset_value); + wmb(); /* Make sure this is visible to HW (paranoia?) */ + + /* Check that the GPU does indeed update the CSB entries! */ + memset(execlists->csb_status, -1, (reset_value + 1) * sizeof(u64)); + invalidate_csb_entries(&execlists->csb_status[0], + &execlists->csb_status[reset_value]); + + /* Once more for luck and our trusty paranoia */ + ENGINE_WRITE(engine, RING_CONTEXT_STATUS_PTR, + 0xffff << 16 | reset_value << 8 | reset_value); + ENGINE_POSTING_READ(engine, RING_CONTEXT_STATUS_PTR); + + GEM_BUG_ON(READ_ONCE(*execlists->csb_write) != reset_value); +} + +static void sanitize_hwsp(struct intel_engine_cs *engine) +{ + struct intel_timeline *tl; + + list_for_each_entry(tl, &engine->status_page.timelines, engine_link) + intel_timeline_reset_seqno(tl); +} + +static void execlists_sanitize(struct intel_engine_cs *engine) +{ + GEM_BUG_ON(execlists_active(&engine->execlists)); + + /* + * Poison residual state on resume, in case the suspend didn't! + * + * We have to assume that across suspend/resume (or other loss + * of control) that the contents of our pinned buffers has been + * lost, replaced by garbage. Since this doesn't always happen, + * let's poison such state so that we more quickly spot when + * we falsely assume it has been preserved. + */ + if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) + memset(engine->status_page.addr, POISON_INUSE, PAGE_SIZE); + + reset_csb_pointers(engine); + + /* + * The kernel_context HWSP is stored in the status_page. As above, + * that may be lost on resume/initialisation, and so we need to + * reset the value in the HWSP. + */ + sanitize_hwsp(engine); + + /* And scrub the dirty cachelines for the HWSP */ + clflush_cache_range(engine->status_page.addr, PAGE_SIZE); +} + +static void enable_error_interrupt(struct intel_engine_cs *engine) +{ + u32 status; + + engine->execlists.error_interrupt = 0; + ENGINE_WRITE(engine, RING_EMR, ~0u); + ENGINE_WRITE(engine, RING_EIR, ~0u); /* clear all existing errors */ + + status = ENGINE_READ(engine, RING_ESR); + if (unlikely(status)) { + drm_err(&engine->i915->drm, + "engine '%s' resumed still in error: %08x\n", + engine->name, status); + __intel_gt_reset(engine->gt, engine->mask); + } + + /* + * On current gen8+, we have 2 signals to play with + * + * - I915_ERROR_INSTUCTION (bit 0) + * + * Generate an error if the command parser encounters an invalid + * instruction + * + * This is a fatal error. + * + * - CP_PRIV (bit 2) + * + * Generate an error on privilege violation (where the CP replaces + * the instruction with a no-op). This also fires for writes into + * read-only scratch pages. + * + * This is a non-fatal error, parsing continues. + * + * * there are a few others defined for odd HW that we do not use + * + * Since CP_PRIV fires for cases where we have chosen to ignore the + * error (as the HW is validating and suppressing the mistakes), we + * only unmask the instruction error bit. + */ + ENGINE_WRITE(engine, RING_EMR, ~I915_ERROR_INSTRUCTION); +} + +static void enable_execlists(struct intel_engine_cs *engine) +{ + u32 mode; + + assert_forcewakes_active(engine->uncore, FORCEWAKE_ALL); + + intel_engine_set_hwsp_writemask(engine, ~0u); /* HWSTAM */ + + if (INTEL_GEN(engine->i915) >= 11) + mode = _MASKED_BIT_ENABLE(GEN11_GFX_DISABLE_LEGACY_MODE); + else + mode = _MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE); + ENGINE_WRITE_FW(engine, RING_MODE_GEN7, mode); + + ENGINE_WRITE_FW(engine, RING_MI_MODE, _MASKED_BIT_DISABLE(STOP_RING)); + + ENGINE_WRITE_FW(engine, + RING_HWS_PGA, + i915_ggtt_offset(engine->status_page.vma)); + ENGINE_POSTING_READ(engine, RING_HWS_PGA); + + enable_error_interrupt(engine); +} + +static bool unexpected_starting_state(struct intel_engine_cs *engine) +{ + bool unexpected = false; + + if (ENGINE_READ_FW(engine, RING_MI_MODE) & STOP_RING) { + drm_dbg(&engine->i915->drm, + "STOP_RING still set in RING_MI_MODE\n"); + unexpected = true; + } + + return unexpected; +} + +static int execlists_resume(struct intel_engine_cs *engine) +{ + intel_mocs_init_engine(engine); + + intel_breadcrumbs_reset(engine->breadcrumbs); + + if (GEM_SHOW_DEBUG() && unexpected_starting_state(engine)) { + struct drm_printer p = drm_debug_printer(__func__); + + intel_engine_dump(engine, &p, NULL); + } + + enable_execlists(engine); + + return 0; +} + +static void execlists_reset_prepare(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + + ENGINE_TRACE(engine, "depth<-%d\n", + atomic_read(&execlists->tasklet.count)); + + /* + * Prevent request submission to the hardware until we have + * completed the reset in i915_gem_reset_finish(). If a request + * is completed by one engine, it may then queue a request + * to a second via its execlists->tasklet *just* as we are + * calling engine->resume() and also writing the ELSP. + * Turning off the execlists->tasklet until the reset is over + * prevents the race. + */ + __tasklet_disable_sync_once(&execlists->tasklet); + GEM_BUG_ON(!reset_in_progress(execlists)); + + /* + * We stop engines, otherwise we might get failed reset and a + * dead gpu (on elk). Also as modern gpu as kbl can suffer + * from system hang if batchbuffer is progressing when + * the reset is issued, regardless of READY_TO_RESET ack. + * Thus assume it is best to stop engines on all gens + * where we have a gpu reset. + * + * WaKBLVECSSemaphoreWaitPoll:kbl (on ALL_ENGINES) + * + * FIXME: Wa for more modern gens needs to be validated + */ + ring_set_paused(engine, 1); + intel_engine_stop_cs(engine); + + engine->execlists.reset_ccid = active_ccid(engine); +} + +static struct i915_request ** +reset_csb(struct intel_engine_cs *engine, struct i915_request **inactive) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + + mb(); /* paranoia: read the CSB pointers from after the reset */ + clflush(execlists->csb_write); + mb(); + + inactive = process_csb(engine, inactive); /* drain preemption events */ + + /* Following the reset, we need to reload the CSB read/write pointers */ + reset_csb_pointers(engine); + + return inactive; +} + +static void +execlists_reset_active(struct intel_engine_cs *engine, bool stalled) +{ + struct intel_context *ce; + struct i915_request *rq; + u32 head; + + /* + * Save the currently executing context, even if we completed + * its request, it was still running at the time of the + * reset and will have been clobbered. + */ + rq = active_context(engine, engine->execlists.reset_ccid); + if (!rq) + return; + + ce = rq->context; + GEM_BUG_ON(!i915_vma_is_pinned(ce->state)); + + if (__i915_request_is_complete(rq)) { + /* Idle context; tidy up the ring so we can restart afresh */ + head = intel_ring_wrap(ce->ring, rq->tail); + goto out_replay; + } + + /* We still have requests in-flight; the engine should be active */ + GEM_BUG_ON(!intel_engine_pm_is_awake(engine)); + + /* Context has requests still in-flight; it should not be idle! */ + GEM_BUG_ON(i915_active_is_idle(&ce->active)); + + rq = active_request(ce->timeline, rq); + head = intel_ring_wrap(ce->ring, rq->head); + GEM_BUG_ON(head == ce->ring->tail); + + /* + * If this request hasn't started yet, e.g. it is waiting on a + * semaphore, we need to avoid skipping the request or else we + * break the signaling chain. However, if the context is corrupt + * the request will not restart and we will be stuck with a wedged + * device. It is quite often the case that if we issue a reset + * while the GPU is loading the context image, that the context + * image becomes corrupt. + * + * Otherwise, if we have not started yet, the request should replay + * perfectly and we do not need to flag the result as being erroneous. + */ + if (!__i915_request_has_started(rq)) + goto out_replay; + + /* + * If the request was innocent, we leave the request in the ELSP + * and will try to replay it on restarting. The context image may + * have been corrupted by the reset, in which case we may have + * to service a new GPU hang, but more likely we can continue on + * without impact. + * + * If the request was guilty, we presume the context is corrupt + * and have to at least restore the RING register in the context + * image back to the expected values to skip over the guilty request. + */ + __i915_request_reset(rq, stalled); + + /* + * We want a simple context + ring to execute the breadcrumb update. + * We cannot rely on the context being intact across the GPU hang, + * so clear it and rebuild just what we need for the breadcrumb. + * All pending requests for this context will be zapped, and any + * future request will be after userspace has had the opportunity + * to recreate its own state. + */ +out_replay: + ENGINE_TRACE(engine, "replay {head:%04x, tail:%04x}\n", + head, ce->ring->tail); + lrc_reset_regs(ce, engine); + ce->lrc.lrca = lrc_update_regs(ce, engine, head); +} + +static void execlists_reset_csb(struct intel_engine_cs *engine, bool stalled) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + struct i915_request *post[2 * EXECLIST_MAX_PORTS]; + struct i915_request **inactive; + + rcu_read_lock(); + inactive = reset_csb(engine, post); + + execlists_reset_active(engine, true); + + inactive = cancel_port_requests(execlists, inactive); + post_process_csb(post, inactive); + rcu_read_unlock(); +} + +static void execlists_reset_rewind(struct intel_engine_cs *engine, bool stalled) +{ + unsigned long flags; + + ENGINE_TRACE(engine, "\n"); + + /* Process the csb, find the guilty context and throw away */ + execlists_reset_csb(engine, stalled); + + /* Push back any incomplete requests for replay after the reset. */ + rcu_read_lock(); + spin_lock_irqsave(&engine->active.lock, flags); + __unwind_incomplete_requests(engine); + spin_unlock_irqrestore(&engine->active.lock, flags); + rcu_read_unlock(); +} + +static void nop_submission_tasklet(unsigned long data) +{ + struct intel_engine_cs * const engine = (struct intel_engine_cs *)data; + + /* The driver is wedged; don't process any more events. */ + WRITE_ONCE(engine->execlists.queue_priority_hint, INT_MIN); +} + +static void execlists_reset_cancel(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + struct i915_request *rq, *rn; + struct rb_node *rb; + unsigned long flags; + + ENGINE_TRACE(engine, "\n"); + + /* + * Before we call engine->cancel_requests(), we should have exclusive + * access to the submission state. This is arranged for us by the + * caller disabling the interrupt generation, the tasklet and other + * threads that may then access the same state, giving us a free hand + * to reset state. However, we still need to let lockdep be aware that + * we know this state may be accessed in hardirq context, so we + * disable the irq around this manipulation and we want to keep + * the spinlock focused on its duties and not accidentally conflate + * coverage to the submission's irq state. (Similarly, although we + * shouldn't need to disable irq around the manipulation of the + * submission's irq state, we also wish to remind ourselves that + * it is irq state.) + */ + execlists_reset_csb(engine, true); + + rcu_read_lock(); + spin_lock_irqsave(&engine->active.lock, flags); + + /* Mark all executing requests as skipped. */ + list_for_each_entry(rq, &engine->active.requests, sched.link) + i915_request_mark_eio(rq); + intel_engine_signal_breadcrumbs(engine); + + /* Flush the queued requests to the timeline list (for retiring). */ + while ((rb = rb_first_cached(&execlists->queue))) { + struct i915_priolist *p = to_priolist(rb); + int i; + + priolist_for_each_request_consume(rq, rn, p, i) { + i915_request_mark_eio(rq); + __i915_request_submit(rq); + } + + rb_erase_cached(&p->node, &execlists->queue); + i915_priolist_free(p); + } + + /* On-hold requests will be flushed to timeline upon their release */ + list_for_each_entry(rq, &engine->active.hold, sched.link) + i915_request_mark_eio(rq); + + /* Cancel all attached virtual engines */ + while ((rb = rb_first_cached(&execlists->virtual))) { + struct virtual_engine *ve = + rb_entry(rb, typeof(*ve), nodes[engine->id].rb); + + rb_erase_cached(rb, &execlists->virtual); + RB_CLEAR_NODE(rb); + + spin_lock(&ve->base.active.lock); + rq = fetch_and_zero(&ve->request); + if (rq) { + i915_request_mark_eio(rq); + + rq->engine = engine; + __i915_request_submit(rq); + i915_request_put(rq); + + ve->base.execlists.queue_priority_hint = INT_MIN; + } + spin_unlock(&ve->base.active.lock); + } + + /* Remaining _unready_ requests will be nop'ed when submitted */ + + execlists->queue_priority_hint = INT_MIN; + execlists->queue = RB_ROOT_CACHED; + + GEM_BUG_ON(__tasklet_is_enabled(&execlists->tasklet)); + execlists->tasklet.func = nop_submission_tasklet; + + spin_unlock_irqrestore(&engine->active.lock, flags); + rcu_read_unlock(); +} + +static void execlists_reset_finish(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + + /* + * After a GPU reset, we may have requests to replay. Do so now while + * we still have the forcewake to be sure that the GPU is not allowed + * to sleep before we restart and reload a context. + * + * If the GPU reset fails, the engine may still be alive with requests + * inflight. We expect those to complete, or for the device to be + * reset as the next level of recovery, and as a final resort we + * will declare the device wedged. + */ + GEM_BUG_ON(!reset_in_progress(execlists)); + + /* And kick in case we missed a new request submission. */ + if (__tasklet_enable(&execlists->tasklet)) + __execlists_kick(execlists); + + ENGINE_TRACE(engine, "depth->%d\n", + atomic_read(&execlists->tasklet.count)); +} + +static void gen8_logical_ring_enable_irq(struct intel_engine_cs *engine) +{ + ENGINE_WRITE(engine, RING_IMR, + ~(engine->irq_enable_mask | engine->irq_keep_mask)); + ENGINE_POSTING_READ(engine, RING_IMR); +} + +static void gen8_logical_ring_disable_irq(struct intel_engine_cs *engine) +{ + ENGINE_WRITE(engine, RING_IMR, ~engine->irq_keep_mask); +} + +static void execlists_park(struct intel_engine_cs *engine) +{ + cancel_timer(&engine->execlists.timer); + cancel_timer(&engine->execlists.preempt); +} + +static bool can_preempt(struct intel_engine_cs *engine) +{ + if (INTEL_GEN(engine->i915) > 8) + return true; + + /* GPGPU on bdw requires extra w/a; not implemented */ + return engine->class != RENDER_CLASS; +} + +static void execlists_set_default_submission(struct intel_engine_cs *engine) +{ + engine->submit_request = execlists_submit_request; + engine->schedule = i915_schedule; + engine->execlists.tasklet.func = execlists_submission_tasklet; + + engine->reset.prepare = execlists_reset_prepare; + engine->reset.rewind = execlists_reset_rewind; + engine->reset.cancel = execlists_reset_cancel; + engine->reset.finish = execlists_reset_finish; + + engine->park = execlists_park; + engine->unpark = NULL; + + engine->flags |= I915_ENGINE_SUPPORTS_STATS; + if (!intel_vgpu_active(engine->i915)) { + engine->flags |= I915_ENGINE_HAS_SEMAPHORES; + if (can_preempt(engine)) { + engine->flags |= I915_ENGINE_HAS_PREEMPTION; + if (IS_ACTIVE(CONFIG_DRM_I915_TIMESLICE_DURATION)) + engine->flags |= I915_ENGINE_HAS_TIMESLICES; + } + } + + if (intel_engine_has_preemption(engine)) + engine->emit_bb_start = gen8_emit_bb_start; + else + engine->emit_bb_start = gen8_emit_bb_start_noarb; +} + +static void execlists_shutdown(struct intel_engine_cs *engine) +{ + /* Synchronise with residual timers and any softirq they raise */ + del_timer_sync(&engine->execlists.timer); + del_timer_sync(&engine->execlists.preempt); + tasklet_kill(&engine->execlists.tasklet); +} + +static void execlists_release(struct intel_engine_cs *engine) +{ + engine->sanitize = NULL; /* no longer in control, nothing to sanitize */ + + execlists_shutdown(engine); + + intel_engine_cleanup_common(engine); + lrc_fini_wa_ctx(engine); +} + +static void +logical_ring_default_vfuncs(struct intel_engine_cs *engine) +{ + /* Default vfuncs which can be overriden by each engine. */ + + engine->resume = execlists_resume; + + engine->cops = &execlists_context_ops; + engine->request_alloc = execlists_request_alloc; + + engine->emit_flush = gen8_emit_flush_xcs; + engine->emit_init_breadcrumb = gen8_emit_init_breadcrumb; + engine->emit_fini_breadcrumb = gen8_emit_fini_breadcrumb_xcs; + if (INTEL_GEN(engine->i915) >= 12) { + engine->emit_fini_breadcrumb = gen12_emit_fini_breadcrumb_xcs; + engine->emit_flush = gen12_emit_flush_xcs; + } + engine->set_default_submission = execlists_set_default_submission; + + if (INTEL_GEN(engine->i915) < 11) { + engine->irq_enable = gen8_logical_ring_enable_irq; + engine->irq_disable = gen8_logical_ring_disable_irq; + } else { + /* + * TODO: On Gen11 interrupt masks need to be clear + * to allow C6 entry. Keep interrupts enabled at + * and take the hit of generating extra interrupts + * until a more refined solution exists. + */ + } +} + +static void logical_ring_default_irqs(struct intel_engine_cs *engine) +{ + unsigned int shift = 0; + + if (INTEL_GEN(engine->i915) < 11) { + const u8 irq_shifts[] = { + [RCS0] = GEN8_RCS_IRQ_SHIFT, + [BCS0] = GEN8_BCS_IRQ_SHIFT, + [VCS0] = GEN8_VCS0_IRQ_SHIFT, + [VCS1] = GEN8_VCS1_IRQ_SHIFT, + [VECS0] = GEN8_VECS_IRQ_SHIFT, + }; + + shift = irq_shifts[engine->id]; + } + + engine->irq_enable_mask = GT_RENDER_USER_INTERRUPT << shift; + engine->irq_keep_mask = GT_CONTEXT_SWITCH_INTERRUPT << shift; + engine->irq_keep_mask |= GT_CS_MASTER_ERROR_INTERRUPT << shift; + engine->irq_keep_mask |= GT_WAIT_SEMAPHORE_INTERRUPT << shift; +} + +static void rcs_submission_override(struct intel_engine_cs *engine) +{ + switch (INTEL_GEN(engine->i915)) { + case 12: + engine->emit_flush = gen12_emit_flush_rcs; + engine->emit_fini_breadcrumb = gen12_emit_fini_breadcrumb_rcs; + break; + case 11: + engine->emit_flush = gen11_emit_flush_rcs; + engine->emit_fini_breadcrumb = gen11_emit_fini_breadcrumb_rcs; + break; + default: + engine->emit_flush = gen8_emit_flush_rcs; + engine->emit_fini_breadcrumb = gen8_emit_fini_breadcrumb_rcs; + break; + } +} + +int intel_execlists_submission_setup(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + struct drm_i915_private *i915 = engine->i915; + struct intel_uncore *uncore = engine->uncore; + u32 base = engine->mmio_base; + + tasklet_init(&engine->execlists.tasklet, + execlists_submission_tasklet, (unsigned long)engine); + timer_setup(&engine->execlists.timer, execlists_timeslice, 0); + timer_setup(&engine->execlists.preempt, execlists_preempt, 0); + + logical_ring_default_vfuncs(engine); + logical_ring_default_irqs(engine); + + if (engine->class == RENDER_CLASS) + rcs_submission_override(engine); + + lrc_init_wa_ctx(engine); + + if (HAS_LOGICAL_RING_ELSQ(i915)) { + execlists->submit_reg = uncore->regs + + i915_mmio_reg_offset(RING_EXECLIST_SQ_CONTENTS(base)); + execlists->ctrl_reg = uncore->regs + + i915_mmio_reg_offset(RING_EXECLIST_CONTROL(base)); + } else { + execlists->submit_reg = uncore->regs + + i915_mmio_reg_offset(RING_ELSP(base)); + } + + execlists->csb_status = + (u64 *)&engine->status_page.addr[I915_HWS_CSB_BUF0_INDEX]; + + execlists->csb_write = + &engine->status_page.addr[intel_hws_csb_write_index(i915)]; + + if (INTEL_GEN(i915) < 11) + execlists->csb_size = GEN8_CSB_ENTRIES; + else + execlists->csb_size = GEN11_CSB_ENTRIES; + + engine->context_tag = GENMASK(BITS_PER_LONG - 2, 0); + if (INTEL_GEN(engine->i915) >= 11) { + execlists->ccid |= engine->instance << (GEN11_ENGINE_INSTANCE_SHIFT - 32); + execlists->ccid |= engine->class << (GEN11_ENGINE_CLASS_SHIFT - 32); + } + + /* Finally, take ownership and responsibility for cleanup! */ + engine->sanitize = execlists_sanitize; + engine->release = execlists_release; + + return 0; +} + +static struct list_head *virtual_queue(struct virtual_engine *ve) +{ + return &ve->base.execlists.default_priolist.requests[0]; +} + +static void rcu_virtual_context_destroy(struct work_struct *wrk) +{ + struct virtual_engine *ve = + container_of(wrk, typeof(*ve), rcu.work); + unsigned int n; + + GEM_BUG_ON(ve->context.inflight); + + /* Preempt-to-busy may leave a stale request behind. */ + if (unlikely(ve->request)) { + struct i915_request *old; + + spin_lock_irq(&ve->base.active.lock); + + old = fetch_and_zero(&ve->request); + if (old) { + GEM_BUG_ON(!__i915_request_is_complete(old)); + __i915_request_submit(old); + i915_request_put(old); + } + + spin_unlock_irq(&ve->base.active.lock); + } + + /* + * Flush the tasklet in case it is still running on another core. + * + * This needs to be done before we remove ourselves from the siblings' + * rbtrees as in the case it is running in parallel, it may reinsert + * the rb_node into a sibling. + */ + tasklet_kill(&ve->base.execlists.tasklet); + + /* Decouple ourselves from the siblings, no more access allowed. */ + for (n = 0; n < ve->num_siblings; n++) { + struct intel_engine_cs *sibling = ve->siblings[n]; + struct rb_node *node = &ve->nodes[sibling->id].rb; + + if (RB_EMPTY_NODE(node)) + continue; + + spin_lock_irq(&sibling->active.lock); + + /* Detachment is lazily performed in the execlists tasklet */ + if (!RB_EMPTY_NODE(node)) + rb_erase_cached(node, &sibling->execlists.virtual); + + spin_unlock_irq(&sibling->active.lock); + } + GEM_BUG_ON(__tasklet_is_scheduled(&ve->base.execlists.tasklet)); + GEM_BUG_ON(!list_empty(virtual_queue(ve))); + + lrc_fini(&ve->context); + intel_context_fini(&ve->context); + + intel_breadcrumbs_free(ve->base.breadcrumbs); + intel_engine_free_request_pool(&ve->base); + + kfree(ve->bonds); + kfree(ve); +} + +static void virtual_context_destroy(struct kref *kref) +{ + struct virtual_engine *ve = + container_of(kref, typeof(*ve), context.ref); + + GEM_BUG_ON(!list_empty(&ve->context.signals)); + + /* + * When destroying the virtual engine, we have to be aware that + * it may still be in use from an hardirq/softirq context causing + * the resubmission of a completed request (background completion + * due to preempt-to-busy). Before we can free the engine, we need + * to flush the submission code and tasklets that are still potentially + * accessing the engine. Flushing the tasklets requires process context, + * and since we can guard the resubmit onto the engine with an RCU read + * lock, we can delegate the free of the engine to an RCU worker. + */ + INIT_RCU_WORK(&ve->rcu, rcu_virtual_context_destroy); + queue_rcu_work(system_wq, &ve->rcu); +} + +static void virtual_engine_initial_hint(struct virtual_engine *ve) +{ + int swp; + + /* + * Pick a random sibling on starting to help spread the load around. + * + * New contexts are typically created with exactly the same order + * of siblings, and often started in batches. Due to the way we iterate + * the array of sibling when submitting requests, sibling[0] is + * prioritised for dequeuing. If we make sure that sibling[0] is fairly + * randomised across the system, we also help spread the load by the + * first engine we inspect being different each time. + * + * NB This does not force us to execute on this engine, it will just + * typically be the first we inspect for submission. + */ + swp = prandom_u32_max(ve->num_siblings); + if (swp) + swap(ve->siblings[swp], ve->siblings[0]); +} + +static int virtual_context_alloc(struct intel_context *ce) +{ + struct virtual_engine *ve = container_of(ce, typeof(*ve), context); + + return lrc_alloc(ce, ve->siblings[0]); +} + +static int virtual_context_pre_pin(struct intel_context *ce, + struct i915_gem_ww_ctx *ww, + void **vaddr) +{ + struct virtual_engine *ve = container_of(ce, typeof(*ve), context); + + /* Note: we must use a real engine class for setting up reg state */ + return lrc_pre_pin(ce, ve->siblings[0], ww, vaddr); +} + +static int virtual_context_pin(struct intel_context *ce, void *vaddr) +{ + struct virtual_engine *ve = container_of(ce, typeof(*ve), context); + + return lrc_pin(ce, ve->siblings[0], vaddr); +} + +static void virtual_context_enter(struct intel_context *ce) +{ + struct virtual_engine *ve = container_of(ce, typeof(*ve), context); + unsigned int n; + + for (n = 0; n < ve->num_siblings; n++) + intel_engine_pm_get(ve->siblings[n]); + + intel_timeline_enter(ce->timeline); +} + +static void virtual_context_exit(struct intel_context *ce) +{ + struct virtual_engine *ve = container_of(ce, typeof(*ve), context); + unsigned int n; + + intel_timeline_exit(ce->timeline); + + for (n = 0; n < ve->num_siblings; n++) + intel_engine_pm_put(ve->siblings[n]); +} + +static const struct intel_context_ops virtual_context_ops = { + .flags = COPS_HAS_INFLIGHT, + + .alloc = virtual_context_alloc, + + .pre_pin = virtual_context_pre_pin, + .pin = virtual_context_pin, + .unpin = lrc_unpin, + .post_unpin = lrc_post_unpin, + + .enter = virtual_context_enter, + .exit = virtual_context_exit, + + .destroy = virtual_context_destroy, +}; + +static intel_engine_mask_t virtual_submission_mask(struct virtual_engine *ve) +{ + struct i915_request *rq; + intel_engine_mask_t mask; + + rq = READ_ONCE(ve->request); + if (!rq) + return 0; + + /* The rq is ready for submission; rq->execution_mask is now stable. */ + mask = rq->execution_mask; + if (unlikely(!mask)) { + /* Invalid selection, submit to a random engine in error */ + i915_request_set_error_once(rq, -ENODEV); + mask = ve->siblings[0]->mask; + } + + ENGINE_TRACE(&ve->base, "rq=%llx:%lld, mask=%x, prio=%d\n", + rq->fence.context, rq->fence.seqno, + mask, ve->base.execlists.queue_priority_hint); + + return mask; +} + +static void virtual_submission_tasklet(unsigned long data) +{ + struct virtual_engine * const ve = (struct virtual_engine *)data; + const int prio = READ_ONCE(ve->base.execlists.queue_priority_hint); + intel_engine_mask_t mask; + unsigned int n; + + rcu_read_lock(); + mask = virtual_submission_mask(ve); + rcu_read_unlock(); + if (unlikely(!mask)) + return; + + for (n = 0; n < ve->num_siblings; n++) { + struct intel_engine_cs *sibling = READ_ONCE(ve->siblings[n]); + struct ve_node * const node = &ve->nodes[sibling->id]; + struct rb_node **parent, *rb; + bool first; + + if (!READ_ONCE(ve->request)) + break; /* already handled by a sibling's tasklet */ + + spin_lock_irq(&sibling->active.lock); + + if (unlikely(!(mask & sibling->mask))) { + if (!RB_EMPTY_NODE(&node->rb)) { + rb_erase_cached(&node->rb, + &sibling->execlists.virtual); + RB_CLEAR_NODE(&node->rb); + } + + goto unlock_engine; + } + + if (unlikely(!RB_EMPTY_NODE(&node->rb))) { + /* + * Cheat and avoid rebalancing the tree if we can + * reuse this node in situ. + */ + first = rb_first_cached(&sibling->execlists.virtual) == + &node->rb; + if (prio == node->prio || (prio > node->prio && first)) + goto submit_engine; + + rb_erase_cached(&node->rb, &sibling->execlists.virtual); + } + + rb = NULL; + first = true; + parent = &sibling->execlists.virtual.rb_root.rb_node; + while (*parent) { + struct ve_node *other; + + rb = *parent; + other = rb_entry(rb, typeof(*other), rb); + if (prio > other->prio) { + parent = &rb->rb_left; + } else { + parent = &rb->rb_right; + first = false; + } + } + + rb_link_node(&node->rb, rb, parent); + rb_insert_color_cached(&node->rb, + &sibling->execlists.virtual, + first); + +submit_engine: + GEM_BUG_ON(RB_EMPTY_NODE(&node->rb)); + node->prio = prio; + if (first && prio > sibling->execlists.queue_priority_hint) + tasklet_hi_schedule(&sibling->execlists.tasklet); + +unlock_engine: + spin_unlock_irq(&sibling->active.lock); + + if (intel_context_inflight(&ve->context)) + break; + } +} + +static void virtual_submit_request(struct i915_request *rq) +{ + struct virtual_engine *ve = to_virtual_engine(rq->engine); + unsigned long flags; + + ENGINE_TRACE(&ve->base, "rq=%llx:%lld\n", + rq->fence.context, + rq->fence.seqno); + + GEM_BUG_ON(ve->base.submit_request != virtual_submit_request); + + spin_lock_irqsave(&ve->base.active.lock, flags); + + /* By the time we resubmit a request, it may be completed */ + if (__i915_request_is_complete(rq)) { + __i915_request_submit(rq); + goto unlock; + } + + if (ve->request) { /* background completion from preempt-to-busy */ + GEM_BUG_ON(!__i915_request_is_complete(ve->request)); + __i915_request_submit(ve->request); + i915_request_put(ve->request); + } + + ve->base.execlists.queue_priority_hint = rq_prio(rq); + ve->request = i915_request_get(rq); + + GEM_BUG_ON(!list_empty(virtual_queue(ve))); + list_move_tail(&rq->sched.link, virtual_queue(ve)); + + tasklet_hi_schedule(&ve->base.execlists.tasklet); + +unlock: + spin_unlock_irqrestore(&ve->base.active.lock, flags); +} + +static struct ve_bond * +virtual_find_bond(struct virtual_engine *ve, + const struct intel_engine_cs *master) +{ + int i; + + for (i = 0; i < ve->num_bonds; i++) { + if (ve->bonds[i].master == master) + return &ve->bonds[i]; + } + + return NULL; +} + +static void +virtual_bond_execute(struct i915_request *rq, struct dma_fence *signal) +{ + struct virtual_engine *ve = to_virtual_engine(rq->engine); + intel_engine_mask_t allowed, exec; + struct ve_bond *bond; + + allowed = ~to_request(signal)->engine->mask; + + bond = virtual_find_bond(ve, to_request(signal)->engine); + if (bond) + allowed &= bond->sibling_mask; + + /* Restrict the bonded request to run on only the available engines */ + exec = READ_ONCE(rq->execution_mask); + while (!try_cmpxchg(&rq->execution_mask, &exec, exec & allowed)) + ; + + /* Prevent the master from being re-run on the bonded engines */ + to_request(signal)->execution_mask &= ~allowed; +} + +struct intel_context * +intel_execlists_create_virtual(struct intel_engine_cs **siblings, + unsigned int count) +{ + struct virtual_engine *ve; + unsigned int n; + int err; + + if (count == 0) + return ERR_PTR(-EINVAL); + + if (count == 1) + return intel_context_create(siblings[0]); + + ve = kzalloc(struct_size(ve, siblings, count), GFP_KERNEL); + if (!ve) + return ERR_PTR(-ENOMEM); + + ve->base.i915 = siblings[0]->i915; + ve->base.gt = siblings[0]->gt; + ve->base.uncore = siblings[0]->uncore; + ve->base.id = -1; + + ve->base.class = OTHER_CLASS; + ve->base.uabi_class = I915_ENGINE_CLASS_INVALID; + ve->base.instance = I915_ENGINE_CLASS_INVALID_VIRTUAL; + ve->base.uabi_instance = I915_ENGINE_CLASS_INVALID_VIRTUAL; + + /* + * The decision on whether to submit a request using semaphores + * depends on the saturated state of the engine. We only compute + * this during HW submission of the request, and we need for this + * state to be globally applied to all requests being submitted + * to this engine. Virtual engines encompass more than one physical + * engine and so we cannot accurately tell in advance if one of those + * engines is already saturated and so cannot afford to use a semaphore + * and be pessimized in priority for doing so -- if we are the only + * context using semaphores after all other clients have stopped, we + * will be starved on the saturated system. Such a global switch for + * semaphores is less than ideal, but alas is the current compromise. + */ + ve->base.saturated = ALL_ENGINES; + + snprintf(ve->base.name, sizeof(ve->base.name), "virtual"); + + intel_engine_init_active(&ve->base, ENGINE_VIRTUAL); + intel_engine_init_execlists(&ve->base); + + ve->base.cops = &virtual_context_ops; + ve->base.request_alloc = execlists_request_alloc; + + ve->base.schedule = i915_schedule; + ve->base.submit_request = virtual_submit_request; + ve->base.bond_execute = virtual_bond_execute; + + INIT_LIST_HEAD(virtual_queue(ve)); + ve->base.execlists.queue_priority_hint = INT_MIN; + tasklet_init(&ve->base.execlists.tasklet, + virtual_submission_tasklet, + (unsigned long)ve); + + intel_context_init(&ve->context, &ve->base); + + ve->base.breadcrumbs = intel_breadcrumbs_create(NULL); + if (!ve->base.breadcrumbs) { + err = -ENOMEM; + goto err_put; + } + + for (n = 0; n < count; n++) { + struct intel_engine_cs *sibling = siblings[n]; + + GEM_BUG_ON(!is_power_of_2(sibling->mask)); + if (sibling->mask & ve->base.mask) { + DRM_DEBUG("duplicate %s entry in load balancer\n", + sibling->name); + err = -EINVAL; + goto err_put; + } + + /* + * The virtual engine implementation is tightly coupled to + * the execlists backend -- we push out request directly + * into a tree inside each physical engine. We could support + * layering if we handle cloning of the requests and + * submitting a copy into each backend. + */ + if (sibling->execlists.tasklet.func != + execlists_submission_tasklet) { + err = -ENODEV; + goto err_put; + } + + GEM_BUG_ON(RB_EMPTY_NODE(&ve->nodes[sibling->id].rb)); + RB_CLEAR_NODE(&ve->nodes[sibling->id].rb); + + ve->siblings[ve->num_siblings++] = sibling; + ve->base.mask |= sibling->mask; + + /* + * All physical engines must be compatible for their emission + * functions (as we build the instructions during request + * construction and do not alter them before submission + * on the physical engine). We use the engine class as a guide + * here, although that could be refined. + */ + if (ve->base.class != OTHER_CLASS) { + if (ve->base.class != sibling->class) { + DRM_DEBUG("invalid mixing of engine class, sibling %d, already %d\n", + sibling->class, ve->base.class); + err = -EINVAL; + goto err_put; + } + continue; + } + + ve->base.class = sibling->class; + ve->base.uabi_class = sibling->uabi_class; + snprintf(ve->base.name, sizeof(ve->base.name), + "v%dx%d", ve->base.class, count); + ve->base.context_size = sibling->context_size; + + ve->base.emit_bb_start = sibling->emit_bb_start; + ve->base.emit_flush = sibling->emit_flush; + ve->base.emit_init_breadcrumb = sibling->emit_init_breadcrumb; + ve->base.emit_fini_breadcrumb = sibling->emit_fini_breadcrumb; + ve->base.emit_fini_breadcrumb_dw = + sibling->emit_fini_breadcrumb_dw; + + ve->base.flags = sibling->flags; + } + + ve->base.flags |= I915_ENGINE_IS_VIRTUAL; + + virtual_engine_initial_hint(ve); + return &ve->context; + +err_put: + intel_context_put(&ve->context); + return ERR_PTR(err); +} + +struct intel_context * +intel_execlists_clone_virtual(struct intel_engine_cs *src) +{ + struct virtual_engine *se = to_virtual_engine(src); + struct intel_context *dst; + + dst = intel_execlists_create_virtual(se->siblings, + se->num_siblings); + if (IS_ERR(dst)) + return dst; + + if (se->num_bonds) { + struct virtual_engine *de = to_virtual_engine(dst->engine); + + de->bonds = kmemdup(se->bonds, + sizeof(*se->bonds) * se->num_bonds, + GFP_KERNEL); + if (!de->bonds) { + intel_context_put(dst); + return ERR_PTR(-ENOMEM); + } + + de->num_bonds = se->num_bonds; + } + + return dst; +} + +int intel_virtual_engine_attach_bond(struct intel_engine_cs *engine, + const struct intel_engine_cs *master, + const struct intel_engine_cs *sibling) +{ + struct virtual_engine *ve = to_virtual_engine(engine); + struct ve_bond *bond; + int n; + + /* Sanity check the sibling is part of the virtual engine */ + for (n = 0; n < ve->num_siblings; n++) + if (sibling == ve->siblings[n]) + break; + if (n == ve->num_siblings) + return -EINVAL; + + bond = virtual_find_bond(ve, master); + if (bond) { + bond->sibling_mask |= sibling->mask; + return 0; + } + + bond = krealloc(ve->bonds, + sizeof(*bond) * (ve->num_bonds + 1), + GFP_KERNEL); + if (!bond) + return -ENOMEM; + + bond[ve->num_bonds].master = master; + bond[ve->num_bonds].sibling_mask = sibling->mask; + + ve->bonds = bond; + ve->num_bonds++; + + return 0; +} + +void intel_execlists_show_requests(struct intel_engine_cs *engine, + struct drm_printer *m, + void (*show_request)(struct drm_printer *m, + const struct i915_request *rq, + const char *prefix, + int indent), + unsigned int max) +{ + const struct intel_engine_execlists *execlists = &engine->execlists; + struct i915_request *rq, *last; + unsigned long flags; + unsigned int count; + struct rb_node *rb; + + spin_lock_irqsave(&engine->active.lock, flags); + + last = NULL; + count = 0; + list_for_each_entry(rq, &engine->active.requests, sched.link) { + if (count++ < max - 1) + show_request(m, rq, "\t\t", 0); + else + last = rq; + } + if (last) { + if (count > max) { + drm_printf(m, + "\t\t...skipping %d executing requests...\n", + count - max); + } + show_request(m, last, "\t\t", 0); + } + + if (execlists->queue_priority_hint != INT_MIN) + drm_printf(m, "\t\tQueue priority hint: %d\n", + READ_ONCE(execlists->queue_priority_hint)); + + last = NULL; + count = 0; + for (rb = rb_first_cached(&execlists->queue); rb; rb = rb_next(rb)) { + struct i915_priolist *p = rb_entry(rb, typeof(*p), node); + int i; + + priolist_for_each_request(rq, p, i) { + if (count++ < max - 1) + show_request(m, rq, "\t\t", 0); + else + last = rq; + } + } + if (last) { + if (count > max) { + drm_printf(m, + "\t\t...skipping %d queued requests...\n", + count - max); + } + show_request(m, last, "\t\t", 0); + } + + last = NULL; + count = 0; + for (rb = rb_first_cached(&execlists->virtual); rb; rb = rb_next(rb)) { + struct virtual_engine *ve = + rb_entry(rb, typeof(*ve), nodes[engine->id].rb); + struct i915_request *rq = READ_ONCE(ve->request); + + if (rq) { + if (count++ < max - 1) + show_request(m, rq, "\t\t", 0); + else + last = rq; + } + } + if (last) { + if (count > max) { + drm_printf(m, + "\t\t...skipping %d virtual requests...\n", + count - max); + } + show_request(m, last, "\t\t", 0); + } + + spin_unlock_irqrestore(&engine->active.lock, flags); +} + +bool +intel_engine_in_execlists_submission_mode(const struct intel_engine_cs *engine) +{ + return engine->set_default_submission == + execlists_set_default_submission; +} + +#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) +#include "selftest_execlists.c" +#endif |