Google Git
Sign in
android-kvm / linux / 3996187f80a0e24bff1959609065d49041cf648d / . / drivers / gpu / drm / i915 / gt / intel_execlists_submission.c
blob: 72090f52fb850fedb0702069ba662cf9f586998a [file] [log] [blame]
// 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 <linux/string_helpers.h>
#include "i915_drv.h"
#include "i915_reg.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_heartbeat.h"
#include "intel_engine_pm.h"
#include "intel_engine_regs.h"
#include "intel_engine_stats.h"
#include "intel_execlists_submission.h"
#include "intel_gt.h"
#include "intel_gt_irq.h"
#include "intel_gt_pm.h"
#include "intel_gt_regs.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)
#define XEHP_CTX_STATUS_SWITCHED_TO_NEW_QUEUE BIT(1) /* upper csb dword */
#define XEHP_CSB_SW_CTX_ID_MASK GENMASK(31, 10)
#define XEHP_IDLE_CTX_ID 0xFFFF
#define XEHP_CSB_CTX_VALID(csb_dw) \
(FIELD_GET(XEHP_CSB_SW_CTX_ID_MASK, csb_dw) != XEHP_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];
/* 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 intel_context *
execlists_create_virtual(struct intel_engine_cs **siblings, unsigned int count,
unsigned long flags);
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 i915_sched_engine *sched_engine)
{
struct rb_node *rb;
rb = rb_first_cached(&sched_engine->queue);
if (!rb)
return INT_MIN;
return to_priolist(rb)->priority;
}
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->sched_engine->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->sched_engine->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->sched_engine)) > 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->sched_engine->lock);
list_for_each_entry_safe_reverse(rq, rn,
&engine->sched_engine->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->sched_engine,
prio);
}
GEM_BUG_ON(i915_sched_engine_is_empty(engine->sched_engine));
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 bool bad_request(const struct i915_request *rq)
{
return rq->fence.error && i915_request_started(rq);
}
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_exiting(ce);
if (unlikely(!intel_context_is_schedulable(ce) || bad_request(rq)))
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 if (GRAPHICS_VER_FULL(engine->i915) >= IP_VER(12, 55)) {
/* We don't need a strict matching tag, just different values */
unsigned int tag = ffs(READ_ONCE(engine->context_tag));
GEM_BUG_ON(tag == 0 || tag >= BITS_PER_LONG);
clear_bit(tag - 1, &engine->context_tag);
ce->lrc.ccid = tag << (XEHP_SW_CTX_ID_SHIFT - 32);
BUILD_BUG_ON(BITS_PER_LONG > GEN12_MAX_CONTEXT_HW_ID);
} 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->sched_engine->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->sched_engine->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.sched_engine->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->sched_engine->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;
if (GRAPHICS_VER_FULL(engine->i915) >= IP_VER(12, 55)) {
ccid >>= XEHP_SW_CTX_ID_SHIFT - 32;
ccid &= XEHP_MAX_CONTEXT_HW_ID;
} else {
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);
}
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_untracked(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 u32 map_i915_prio_to_lrc_desc_prio(int prio)
{
if (prio > I915_PRIORITY_NORMAL)
return GEN12_CTX_PRIORITY_HIGH;
else if (prio < I915_PRIORITY_NORMAL)
return GEN12_CTX_PRIORITY_LOW;
else
return GEN12_CTX_PRIORITY_NORMAL;
}
static u64 execlists_update_context(struct i915_request *rq)
{
struct intel_context *ce = rq->context;
u64 desc;
u32 tail, prev;
desc = ce->lrc.desc;
if (rq->engine->flags & I915_ENGINE_HAS_EU_PRIORITY)
desc |= map_i915_prio_to_lrc_desc_prio(rq_prio(rq));
/*
* 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_cs *engine)
{
return unlikely(!__tasklet_is_enabled(&engine->sched_engine->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, *prev = NULL;
struct intel_context *ce = NULL;
u32 ccid = -1;
trace_ports(execlists, msg, execlists->pending);
/* We may be messing around with the lists during reset, lalala */
if (reset_in_progress(engine))
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.
*
* NB: Due to the async nature of preempt-to-busy and request
* cancellation we need to handle the case where request
* becomes a sentinel in parallel to CSB processing.
*/
if (prev && i915_request_has_sentinel(prev) &&
!READ_ONCE(prev->fence.error)) {
GEM_TRACE_ERR("%s: context:%llx after sentinel in pending[%zd]\n",
engine->name,
ce->timeline->fence_context,
port - execlists->pending);
return false;
}
prev = 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));
if (!i915_request_is_ready(w))
continue;
if (rq_prio(w) < rq_prio(rq))
continue;
GEM_BUG_ON(rq_prio(w) > rq_prio(rq));
GEM_BUG_ON(i915_request_is_active(w));
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->sched_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->sched_engine->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 (!i915_sched_engine_is_empty(engine->sched_engine)) {
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(&engine->sched_engine->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;
/* Only allow ourselves to force reset the currently active context */
engine->execlists.preempt_target = rq;
/* Force a fast reset for terminated contexts (ignoring sysfs!) */
if (unlikely(intel_context_is_banned(rq->context) || bad_request(rq)))
return INTEL_CONTEXT_BANNED_PREEMPT_TIMEOUT_MS;
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_sched_engine * const sched_engine = engine->sched_engine;
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(&sched_engine->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,
sched_engine->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",
str_yes_no(timer_expired(&execlists->timer)),
last->fence.context, last->fence.seqno,
rq_prio(last),
sched_engine->queue_priority_hint,
str_yes_no(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 preemption 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(&sched_engine->lock);
return;
}
}
}
/* XXX virtual is always taking precedence */
while ((ve = first_virtual_engine(engine))) {
struct i915_request *rq;
spin_lock(&ve->base.sched_engine->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(sched_engine))) {
spin_unlock(&ve->base.sched_engine->lock);
break;
}
if (last && !can_merge_rq(last, rq)) {
spin_unlock(&ve->base.sched_engine->lock);
spin_unlock(&engine->sched_engine->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) ? "*" :
"",
str_yes_no(engine != ve->siblings[0]));
WRITE_ONCE(ve->request, NULL);
WRITE_ONCE(ve->base.sched_engine->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.sched_engine->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(&sched_engine->queue))) {
struct i915_priolist *p = to_priolist(rb);
struct i915_request *rq, *rn;
priolist_for_each_request_consume(rq, rn, p) {
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, &sched_engine->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).
*/
sched_engine->queue_priority_hint = queue_prio(sched_engine);
i915_sched_engine_reset_on_empty(sched_engine);
spin_unlock(&sched_engine->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;
}
/*
* 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
*
* Xe_HP csb shuffles things around compared to TGL:
*
* bits 0-3: context switch detail (same possible values as TGL)
* bits 4-9: engine instance
* bits 10-25: sw context id of the lrc the GT switched to
* bits 26-31: sw counter of the lrc the GT switched to
* bit 32: semaphore wait mode (poll or signal), Only valid when
* switch detail is set to "wait on semaphore"
* bit 33: switched to new queue
* bits 34-41: wait detail (for switch detail 1 to 4)
* bits 42-57: 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 inline bool
__gen12_csb_parse(bool ctx_to_valid, bool ctx_away_valid, bool new_queue,
u8 switch_detail)
{
/*
* 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(!ctx_to_valid);
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(switch_detail);
return false;
}
static bool xehp_csb_parse(const u64 csb)
{
return __gen12_csb_parse(XEHP_CSB_CTX_VALID(lower_32_bits(csb)), /* cxt to */
XEHP_CSB_CTX_VALID(upper_32_bits(csb)), /* cxt away */
upper_32_bits(csb) & XEHP_CTX_STATUS_SWITCHED_TO_NEW_QUEUE,
GEN12_CTX_SWITCH_DETAIL(lower_32_bits(csb)));
}
static bool gen12_csb_parse(const u64 csb)
{
return __gen12_csb_parse(GEN12_CSB_CTX_VALID(lower_32_bits(csb)), /* cxt to */
GEN12_CSB_CTX_VALID(upper_32_bits(csb)), /* cxt away */
lower_32_bits(csb) & GEN12_CTX_STATUS_SWITCHED_TO_NEW_QUEUE,
GEN12_CTX_SWITCH_DETAIL(upper_32_bits(csb)));
}
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(&engine->sched_engine->tasklet) &&
!reset_in_progress(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 (GRAPHICS_VER_FULL(engine->i915) >= IP_VER(12, 55))
promote = xehp_csb_parse(csb);
else if (GRAPHICS_VER(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.
*/
drm_clflush_virt_range(&buf[0], num_entries * sizeof(buf[0]));
/*
* 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 */
struct intel_context *prev_ce = NULL, *active_ce = NULL;
/*
* Note the inherent discrepancy between the HW runtime,
* recorded as part of the context switch, and the CPU
* adjustment for active contexts. We have to hope that
* the delay in processing the CS event is very small
* and consistent. It works to our advantage to have
* the CPU adjustment _undershoot_ (i.e. start later than)
* the CS timestamp so we never overreport the runtime
* and correct overselves later when updating from HW.
*/
if (*prev)
prev_ce = (*prev)->context;
if (*execlists->active)
active_ce = (*execlists->active)->context;
if (prev_ce != active_ce) {
if (prev_ce)
lrc_runtime_stop(prev_ce);
if (active_ce)
lrc_runtime_start(active_ce);
}
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->sched_engine->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->sched_engine->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->sched_engine->hold));
unlock:
spin_unlock_irq(&engine->sched_engine->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->sched_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;
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->sched_engine->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->sched_engine->queue_priority_hint) {
engine->sched_engine->queue_priority_hint = rq_prio(rq);
tasklet_hi_schedule(&engine->sched_engine->tasklet);
}
spin_unlock_irq(&engine->sched_engine->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_KSWAPD_RECLAIM | __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, CORE_DUMP_FLAG_NONE);
if (!cap->error->gt)
goto err_gpu;
cap->error->gt->engine = intel_engine_coredump_alloc(engine, gfp, CORE_DUMP_FLAG_NONE);
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 drm_i915_private *i915 = engine->i915;
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->sched_engine->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->sched_engine->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);
queue_work(i915->unordered_wq, &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->sched_engine->tasklet);
ring_set_paused(engine, 1); /* Freeze the current request in place */
execlists_capture(engine);
intel_engine_reset(engine, msg);
tasklet_enable(&engine->sched_engine->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(struct tasklet_struct *t)
{
struct i915_sched_engine *sched_engine =
from_tasklet(sched_engine, t, tasklet);
struct intel_engine_cs * const engine = sched_engine->private_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))) {
const struct i915_request *rq = *engine->execlists.active;
/*
* If after the preempt-timeout expired, we are still on the
* same active request/context as before we initiated the
* preemption, reset the engine.
*
* However, if we have processed a CS event to switch contexts,
* but not yet processed the CS event for the pending
* preemption, reset the timer allowing the new context to
* gracefully exit.
*/
cancel_timer(&engine->execlists.preempt);
if (rq == engine->execlists.preempt_target)
engine->execlists.error_interrupt |= ERROR_PREEMPT;
else
set_timer_ms(&engine->execlists.preempt,
active_preempt_timeout(engine, rq));
}
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_irq_handler(struct intel_engine_cs *engine, u16 iir)
{
bool tasklet = false;
if (unlikely(iir & GT_CS_MASTER_ERROR_INTERRUPT)) {
u32 eir;
/* Upper 16b are the enabling mask, rsvd for internal errors */
eir = ENGINE_READ(engine, RING_EIR) & GENMASK(15, 0);
ENGINE_TRACE(engine, "CS error: %x\n", eir);
/* Disable the error interrupt until after the reset */
if (likely(eir)) {
ENGINE_WRITE(engine, RING_EMR, ~0u);
ENGINE_WRITE(engine, RING_EIR, eir);
WRITE_ONCE(engine->execlists.error_interrupt, eir);
tasklet = true;
}
}
if (iir & GT_WAIT_SEMAPHORE_INTERRUPT) {
WRITE_ONCE(engine->execlists.yield,
ENGINE_READ_FW(engine, RING_EXECLIST_STATUS_HI));
ENGINE_TRACE(engine, "semaphore yield: %08x\n",
engine->execlists.yield);
if (del_timer(&engine->execlists.timer))
tasklet = true;
}
if (iir & GT_CONTEXT_SWITCH_INTERRUPT)
tasklet = true;
if (iir & GT_RENDER_USER_INTERRUPT)
intel_engine_signal_breadcrumbs(engine);
if (tasklet)
tasklet_hi_schedule(&engine->sched_engine->tasklet);
}
static void __execlists_kick(struct intel_engine_execlists *execlists)
{
struct intel_engine_cs *engine =
container_of(execlists, typeof(*engine), execlists);
/* Kick the tasklet for some interrupt coalescing and reset handling */
tasklet_hi_schedule(&engine->sched_engine->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->sched_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 i915_sched_engine *sched_engine = engine->sched_engine;
if (rq_prio(rq) <= sched_engine->queue_priority_hint)
return false;
sched_engine->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->sched_engine->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->sched_engine->lock, flags);
if (unlikely(ancestor_on_hold(engine, request))) {
RQ_TRACE(request, "ancestor on hold\n");
list_add_tail(&request->sched.link,
&engine->sched_engine->hold);
i915_request_set_hold(request);
} else {
queue_request(engine, request);
GEM_BUG_ON(i915_sched_engine_is_empty(engine->sched_engine));
GEM_BUG_ON(list_empty(&request->sched.link));
if (submit_queue(engine, request))
__execlists_kick(&engine->execlists);
}
spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
}
static int
__execlists_context_pre_pin(struct intel_context *ce,
struct intel_engine_cs *engine,
struct i915_gem_ww_ctx *ww, void **vaddr)
{
int err;
err = lrc_pre_pin(ce, engine, ww, vaddr);
if (err)
return err;
if (!__test_and_set_bit(CONTEXT_INIT_BIT, &ce->flags)) {
lrc_init_state(ce, engine, *vaddr);
__i915_gem_object_flush_map(ce->state->obj, 0, engine->context_size);
}
return 0;
}
static int execlists_context_pre_pin(struct intel_context *ce,
struct i915_gem_ww_ctx *ww,
void **vaddr)
{
return __execlists_context_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 void execlists_context_cancel_request(struct intel_context *ce,
struct i915_request *rq)
{
struct intel_engine_cs *engine = NULL;
i915_request_active_engine(rq, &engine);
if (engine && intel_engine_pulse(engine))
intel_gt_handle_error(engine->gt, engine->mask, 0,
"request cancellation by %s",
current->comm);
}
static struct intel_context *
execlists_create_parallel(struct intel_engine_cs **engines,
unsigned int num_siblings,
unsigned int width)
{
struct intel_context *parent = NULL, *ce, *err;
int i;
GEM_BUG_ON(num_siblings != 1);
for (i = 0; i < width; ++i) {
ce = intel_context_create(engines[i]);
if (IS_ERR(ce)) {
err = ce;
goto unwind;
}
if (i == 0)
parent = ce;
else
intel_context_bind_parent_child(parent, ce);
}
parent->parallel.fence_context = dma_fence_context_alloc(1);
intel_context_set_nopreempt(parent);
for_each_child(parent, ce)
intel_context_set_nopreempt(ce);
return parent;
unwind:
if (parent)
intel_context_put(parent);
return err;
}
static const struct intel_context_ops execlists_context_ops = {
.flags = COPS_HAS_INFLIGHT | COPS_RUNTIME_CYCLES,
.alloc = execlists_context_alloc,
.cancel_request = execlists_context_cancel_request,
.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,
.create_parallel = execlists_create_parallel,
.create_virtual = execlists_create_virtual,
};
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->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));
drm_clflush_virt_range(execlists->csb_status,
execlists->csb_size *
sizeof(execlists->csb_status));
/* 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 */
drm_clflush_virt_range(engine->status_page.addr, PAGE_SIZE);
intel_engine_reset_pinned_contexts(engine);
}
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(engine);
}
/*
* 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 (GRAPHICS_VER(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 int execlists_resume(struct intel_engine_cs *engine)
{
intel_mocs_init_engine(engine);
intel_breadcrumbs_reset(engine->breadcrumbs);
enable_execlists(engine);
if (engine->flags & I915_ENGINE_FIRST_RENDER_COMPUTE)
xehp_enable_ccs_engines(engine);
return 0;
}
static void execlists_reset_prepare(struct intel_engine_cs *engine)
{
ENGINE_TRACE(engine, "depth<-%d\n",
atomic_read(&engine->sched_engine->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(&engine->sched_engine->tasklet);
GEM_BUG_ON(!reset_in_progress(engine));
/*
* 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);
/*
* Wa_22011802037: In addition to stopping the cs, we need
* to wait for any pending mi force wakeups
*/
if (intel_engine_reset_needs_wa_22011802037(engine->gt))
intel_engine_wait_for_pending_mi_fw(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;
drm_clflush_virt_range(execlists->csb_write,
sizeof(execlists->csb_write[0]));
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->sched_engine->lock, flags);
__unwind_incomplete_requests(engine);
spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
rcu_read_unlock();
}
static void nop_submission_tasklet(struct tasklet_struct *t)
{
struct i915_sched_engine *sched_engine =
from_tasklet(sched_engine, t, tasklet);
struct intel_engine_cs * const engine = sched_engine->private_data;
/* The driver is wedged; don't process any more events. */
WRITE_ONCE(engine->sched_engine->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_sched_engine * const sched_engine = engine->sched_engine;
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->sched_engine->lock, flags);
/* Mark all executing requests as skipped. */
list_for_each_entry(rq, &engine->sched_engine->requests, sched.link)
i915_request_put(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(&sched_engine->queue))) {
struct i915_priolist *p = to_priolist(rb);
priolist_for_each_request_consume(rq, rn, p) {
if (i915_request_mark_eio(rq)) {
__i915_request_submit(rq);
i915_request_put(rq);
}
}
rb_erase_cached(&p->node, &sched_engine->queue);
i915_priolist_free(p);
}
/* On-hold requests will be flushed to timeline upon their release */
list_for_each_entry(rq, &sched_engine->hold, sched.link)
i915_request_put(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.sched_engine->lock);
rq = fetch_and_zero(&ve->request);
if (rq) {
if (i915_request_mark_eio(rq)) {
rq->engine = engine;
__i915_request_submit(rq);
i915_request_put(rq);
}
i915_request_put(rq);
ve->base.sched_engine->queue_priority_hint = INT_MIN;
}
spin_unlock(&ve->base.sched_engine->lock);
}
/* Remaining _unready_ requests will be nop'ed when submitted */
sched_engine->queue_priority_hint = INT_MIN;
sched_engine->queue = RB_ROOT_CACHED;
GEM_BUG_ON(__tasklet_is_enabled(&engine->sched_engine->tasklet));
engine->sched_engine->tasklet.callback = nop_submission_tasklet;
spin_unlock_irqrestore(&engine->sched_engine->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(engine));
/* And kick in case we missed a new request submission. */
if (__tasklet_enable(&engine->sched_engine->tasklet))
__execlists_kick(execlists);
ENGINE_TRACE(engine, "depth->%d\n",
atomic_read(&engine->sched_engine->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);
/* Reset upon idling, or we may delay the busy wakeup. */
WRITE_ONCE(engine->sched_engine->queue_priority_hint, INT_MIN);
}
static void add_to_engine(struct i915_request *rq)
{
lockdep_assert_held(&rq->engine->sched_engine->lock);
list_move_tail(&rq->sched.link, &rq->engine->sched_engine->requests);
}
static void remove_from_engine(struct i915_request *rq)
{
struct intel_engine_cs *engine, *locked;
/*
* Virtual engines complicate acquiring the engine timeline lock,
* as their rq->engine pointer is not stable until under that
* engine lock. The simple ploy we use is to take the lock then
* check that the rq still belongs to the newly locked engine.
*/
locked = READ_ONCE(rq->engine);
spin_lock_irq(&locked->sched_engine->lock);
while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
spin_unlock(&locked->sched_engine->lock);
spin_lock(&engine->sched_engine->lock);
locked = engine;
}
list_del_init(&rq->sched.link);
clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
clear_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags);
/* Prevent further __await_execution() registering a cb, then flush */
set_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags);
spin_unlock_irq(&locked->sched_engine->lock);
i915_request_notify_execute_cb_imm(rq);
}
static bool can_preempt(struct intel_engine_cs *engine)
{
return GRAPHICS_VER(engine->i915) > 8;
}
static void kick_execlists(const struct i915_request *rq, int prio)
{
struct intel_engine_cs *engine = rq->engine;
struct i915_sched_engine *sched_engine = engine->sched_engine;
const struct i915_request *inflight;
/*
* We only need to kick the tasklet once for the high priority
* new context we add into the queue.
*/
if (prio <= sched_engine->queue_priority_hint)
return;
rcu_read_lock();
/* Nothing currently active? We're overdue for a submission! */
inflight = execlists_active(&engine->execlists);
if (!inflight)
goto unlock;
/*
* If we are already the currently executing context, don't
* bother evaluating if we should preempt ourselves.
*/
if (inflight->context == rq->context)
goto unlock;
ENGINE_TRACE(engine,
"bumping queue-priority-hint:%d for rq:%llx:%lld, inflight:%llx:%lld prio %d\n",
prio,
rq->fence.context, rq->fence.seqno,
inflight->fence.context, inflight->fence.seqno,
inflight->sched.attr.priority);
sched_engine->queue_priority_hint = prio;
/*
* Allow preemption of low -> normal -> high, but we do
* not allow low priority tasks to preempt other low priority
* tasks under the impression that latency for low priority
* tasks does not matter (as much as background throughput),
* so kiss.
*/
if (prio >= max(I915_PRIORITY_NORMAL, rq_prio(inflight)))
tasklet_hi_schedule(&sched_engine->tasklet);
unlock:
rcu_read_unlock();
}
static void execlists_set_default_submission(struct intel_engine_cs *engine)
{
engine->submit_request = execlists_submit_request;
engine->sched_engine->schedule = i915_schedule;
engine->sched_engine->kick_backend = kick_execlists;
engine->sched_engine->tasklet.callback = execlists_submission_tasklet;
}
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->sched_engine->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 ktime_t __execlists_engine_busyness(struct intel_engine_cs *engine,
ktime_t *now)
{
struct intel_engine_execlists_stats *stats = &engine->stats.execlists;
ktime_t total = stats->total;
/*
* If the engine is executing something at the moment
* add it to the total.
*/
*now = ktime_get();
if (READ_ONCE(stats->active))
total = ktime_add(total, ktime_sub(*now, stats->start));
return total;
}
static ktime_t execlists_engine_busyness(struct intel_engine_cs *engine,
ktime_t *now)
{
struct intel_engine_execlists_stats *stats = &engine->stats.execlists;
unsigned int seq;
ktime_t total;
do {
seq = read_seqcount_begin(&stats->lock);
total = __execlists_engine_busyness(engine, now);
} while (read_seqcount_retry(&stats->lock, seq));
return total;
}
static void
logical_ring_default_vfuncs(struct intel_engine_cs *engine)
{
/* Default vfuncs which can be overridden by each engine. */
engine->resume = execlists_resume;
engine->cops = &execlists_context_ops;
engine->request_alloc = execlists_request_alloc;
engine->add_active_request = add_to_engine;
engine->remove_active_request = remove_from_engine;
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->emit_flush = gen8_emit_flush_xcs;
engine->emit_init_breadcrumb = gen8_emit_init_breadcrumb;
engine->emit_fini_breadcrumb = gen8_emit_fini_breadcrumb_xcs;
if (GRAPHICS_VER(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 (GRAPHICS_VER(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.
*/
}
intel_engine_set_irq_handler(engine, execlists_irq_handler);
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 (CONFIG_DRM_I915_TIMESLICE_DURATION)
engine->flags |= I915_ENGINE_HAS_TIMESLICES;
}
}
if (GRAPHICS_VER_FULL(engine->i915) >= IP_VER(12, 55)) {
if (intel_engine_has_preemption(engine))
engine->emit_bb_start = xehp_emit_bb_start;
else
engine->emit_bb_start = xehp_emit_bb_start_noarb;
} else {
if (intel_engine_has_preemption(engine))
engine->emit_bb_start = gen8_emit_bb_start;
else
engine->emit_bb_start = gen8_emit_bb_start_noarb;
}
engine->busyness = execlists_engine_busyness;
}
static void logical_ring_default_irqs(struct intel_engine_cs *engine)
{
unsigned int shift = 0;
if (GRAPHICS_VER(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 (GRAPHICS_VER(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_setup(&engine->sched_engine->tasklet, execlists_submission_tasklet);
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);
seqcount_init(&engine->stats.execlists.lock);
if (engine->flags & I915_ENGINE_HAS_RCS_REG_STATE)
rcs_submission_override(engine);
lrc_init_wa_ctx(engine);
if (HAS_LOGICAL_RING_ELSQ(i915)) {
execlists->submit_reg = intel_uncore_regs(uncore) +
i915_mmio_reg_offset(RING_EXECLIST_SQ_CONTENTS(base));
execlists->ctrl_reg = intel_uncore_regs(uncore) +
i915_mmio_reg_offset(RING_EXECLIST_CONTROL(base));
engine->fw_domain = intel_uncore_forcewake_for_reg(engine->uncore,
RING_EXECLIST_CONTROL(engine->mmio_base),
FW_REG_WRITE);
} else {
execlists->submit_reg = intel_uncore_regs(uncore) +
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 (GRAPHICS_VER(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 (GRAPHICS_VER(engine->i915) >= 11 &&
GRAPHICS_VER_FULL(engine->i915) < IP_VER(12, 55)) {
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.sched_engine->default_priolist.requests;
}
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.sched_engine->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.sched_engine->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.sched_engine->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->sched_engine->lock);
/* Detachment is lazily performed in the sched_engine->tasklet */
if (!RB_EMPTY_NODE(node))
rb_erase_cached(node, &sibling->execlists.virtual);
spin_unlock_irq(&sibling->sched_engine->lock);
}
GEM_BUG_ON(__tasklet_is_scheduled(&ve->base.sched_engine->tasklet));
GEM_BUG_ON(!list_empty(virtual_queue(ve)));
lrc_fini(&ve->context);
intel_context_fini(&ve->context);
if (ve->base.breadcrumbs)
intel_breadcrumbs_put(ve->base.breadcrumbs);
if (ve->base.sched_engine)
i915_sched_engine_put(ve->base.sched_engine);
intel_engine_free_request_pool(&ve->base);
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(ve->context.engine->i915->unordered_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 = get_random_u32_below(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 __execlists_context_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 struct intel_engine_cs *
virtual_get_sibling(struct intel_engine_cs *engine, unsigned int sibling)
{
struct virtual_engine *ve = to_virtual_engine(engine);
if (sibling >= ve->num_siblings)
return NULL;
return ve->siblings[sibling];
}
static const struct intel_context_ops virtual_context_ops = {
.flags = COPS_HAS_INFLIGHT | COPS_RUNTIME_CYCLES,
.alloc = virtual_context_alloc,
.cancel_request = execlists_context_cancel_request,
.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,
.get_sibling = virtual_get_sibling,
};
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.sched_engine->queue_priority_hint);
return mask;
}
static void virtual_submission_tasklet(struct tasklet_struct *t)
{
struct i915_sched_engine *sched_engine =
from_tasklet(sched_engine, t, tasklet);
struct virtual_engine * const ve =
(struct virtual_engine *)sched_engine->private_data;
const int prio = READ_ONCE(sched_engine->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->sched_engine->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->sched_engine->queue_priority_hint)
tasklet_hi_schedule(&sibling->sched_engine->tasklet);
unlock_engine:
spin_unlock_irq(&sibling->sched_engine->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.sched_engine->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.sched_engine->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.sched_engine->tasklet);
unlock:
spin_unlock_irqrestore(&ve->base.sched_engine->lock, flags);
}
static struct intel_context *
execlists_create_virtual(struct intel_engine_cs **siblings, unsigned int count,
unsigned long flags)
{
struct drm_i915_private *i915 = siblings[0]->i915;
struct virtual_engine *ve;
unsigned int n;
int err;
ve = kzalloc(struct_size(ve, siblings, count), GFP_KERNEL);
if (!ve)
return ERR_PTR(-ENOMEM);
ve->base.i915 = 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_execlists(&ve->base);
ve->base.sched_engine = i915_sched_engine_create(ENGINE_VIRTUAL);
if (!ve->base.sched_engine) {
err = -ENOMEM;
goto err_put;
}
ve->base.sched_engine->private_data = &ve->base;
ve->base.cops = &virtual_context_ops;
ve->base.request_alloc = execlists_request_alloc;
ve->base.sched_engine->schedule = i915_schedule;
ve->base.sched_engine->kick_backend = kick_execlists;
ve->base.submit_request = virtual_submit_request;
INIT_LIST_HEAD(virtual_queue(ve));
tasklet_setup(&ve->base.sched_engine->tasklet, virtual_submission_tasklet);
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_dbg(&i915->drm,
"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->sched_engine->tasklet.callback !=
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;
ve->base.logical_mask |= sibling->logical_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_dbg(&i915->drm,
"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.add_active_request = sibling->add_active_request;
ve->base.remove_active_request = sibling->remove_active_request;
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);
}
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_sched_engine *sched_engine = engine->sched_engine;
struct i915_request *rq, *last;
unsigned long flags;
unsigned int count;
struct rb_node *rb;
spin_lock_irqsave(&sched_engine->lock, flags);
last = NULL;
count = 0;
list_for_each_entry(rq, &sched_engine->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 (sched_engine->queue_priority_hint != INT_MIN)
drm_printf(m, "\t\tQueue priority hint: %d\n",
READ_ONCE(sched_engine->queue_priority_hint));
last = NULL;
count = 0;
for (rb = rb_first_cached(&sched_engine->queue); rb; rb = rb_next(rb)) {
struct i915_priolist *p = rb_entry(rb, typeof(*p), node);
priolist_for_each_request(rq, p) {
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(&sched_engine->lock, flags);
}
void intel_execlists_dump_active_requests(struct intel_engine_cs *engine,
struct i915_request *hung_rq,
struct drm_printer *m)
{
unsigned long flags;
spin_lock_irqsave(&engine->sched_engine->lock, flags);
intel_engine_dump_active_requests(&engine->sched_engine->requests, hung_rq, m);
drm_printf(m, "\tOn hold?: %zu\n",
list_count_nodes(&engine->sched_engine->hold));
spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftest_execlists.c"
#endif