// SPDX-License-Identifier: MIT
/*
 * Copyright © 2014 Intel Corporation
 */

#include <linux/circ_buf.h>

#include "gem/i915_gem_context.h"
#include "gt/gen8_engine_cs.h"
#include "gt/intel_breadcrumbs.h"
#include "gt/intel_context.h"
#include "gt/intel_engine_pm.h"
#include "gt/intel_engine_heartbeat.h"
#include "gt/intel_gt.h"
#include "gt/intel_gt_irq.h"
#include "gt/intel_gt_pm.h"
#include "gt/intel_gt_requests.h"
#include "gt/intel_lrc.h"
#include "gt/intel_lrc_reg.h"
#include "gt/intel_mocs.h"
#include "gt/intel_ring.h"

#include "intel_guc_submission.h"

#include "i915_drv.h"
#include "i915_trace.h"

/**
 * DOC: GuC-based command submission
 *
 * IMPORTANT NOTE: GuC submission is currently not supported in i915. The GuC
 * firmware is moving to an updated submission interface and we plan to
 * turn submission back on when that lands. The below documentation (and related
 * code) matches the old submission model and will be updated as part of the
 * upgrade to the new flow.
 *
 * GuC stage descriptor:
 * During initialization, the driver allocates a static pool of 1024 such
 * descriptors, and shares them with the GuC. Currently, we only use one
 * descriptor. This stage descriptor lets the GuC know about the workqueue and
 * process descriptor. Theoretically, it also lets the GuC know about our HW
 * contexts (context ID, etc...), but we actually employ a kind of submission
 * where the GuC uses the LRCA sent via the work item instead. This is called
 * a "proxy" submission.
 *
 * The Scratch registers:
 * There are 16 MMIO-based registers start from 0xC180. The kernel driver writes
 * a value to the action register (SOFT_SCRATCH_0) along with any data. It then
 * triggers an interrupt on the GuC via another register write (0xC4C8).
 * Firmware writes a success/fail code back to the action register after
 * processes the request. The kernel driver polls waiting for this update and
 * then proceeds.
 *
 * Work Items:
 * There are several types of work items that the host may place into a
 * workqueue, each with its own requirements and limitations. Currently only
 * WQ_TYPE_INORDER is needed to support legacy submission via GuC, which
 * represents in-order queue. The kernel driver packs ring tail pointer and an
 * ELSP context descriptor dword into Work Item.
 * See guc_add_request()
 *
 */

/* GuC Virtual Engine */
struct guc_virtual_engine {
        struct intel_engine_cs base;
        struct intel_context context;
};

static struct intel_context *
guc_create_virtual(struct intel_engine_cs **siblings, unsigned int count);

#define GUC_REQUEST_SIZE 64 /* bytes */

/*
 * Below is a set of functions which control the GuC scheduling state which do
 * not require a lock as all state transitions are mutually exclusive. i.e. It
 * is not possible for the context pinning code and submission, for the same
 * context, to be executing simultaneously. We still need an atomic as it is
 * possible for some of the bits to changing at the same time though.
 */
#define SCHED_STATE_NO_LOCK_ENABLED                     BIT(0)
#define SCHED_STATE_NO_LOCK_PENDING_ENABLE              BIT(1)
#define SCHED_STATE_NO_LOCK_REGISTERED                  BIT(2)
static inline bool context_enabled(struct intel_context *ce)
{
        return (atomic_read(&ce->guc_sched_state_no_lock) &
                SCHED_STATE_NO_LOCK_ENABLED);
}

static inline void set_context_enabled(struct intel_context *ce)
{
        atomic_or(SCHED_STATE_NO_LOCK_ENABLED, &ce->guc_sched_state_no_lock);
}

static inline void clr_context_enabled(struct intel_context *ce)
{
        atomic_and((u32)~SCHED_STATE_NO_LOCK_ENABLED,
                   &ce->guc_sched_state_no_lock);
}

static inline bool context_pending_enable(struct intel_context *ce)
{
        return (atomic_read(&ce->guc_sched_state_no_lock) &
                SCHED_STATE_NO_LOCK_PENDING_ENABLE);
}

static inline void set_context_pending_enable(struct intel_context *ce)
{
        atomic_or(SCHED_STATE_NO_LOCK_PENDING_ENABLE,
                  &ce->guc_sched_state_no_lock);
}

static inline void clr_context_pending_enable(struct intel_context *ce)
{
        atomic_and((u32)~SCHED_STATE_NO_LOCK_PENDING_ENABLE,
                   &ce->guc_sched_state_no_lock);
}

static inline bool context_registered(struct intel_context *ce)
{
        return (atomic_read(&ce->guc_sched_state_no_lock) &
                SCHED_STATE_NO_LOCK_REGISTERED);
}

static inline void set_context_registered(struct intel_context *ce)
{
        atomic_or(SCHED_STATE_NO_LOCK_REGISTERED,
                  &ce->guc_sched_state_no_lock);
}

static inline void clr_context_registered(struct intel_context *ce)
{
        atomic_and((u32)~SCHED_STATE_NO_LOCK_REGISTERED,
                   &ce->guc_sched_state_no_lock);
}

/*
 * Below is a set of functions which control the GuC scheduling state which
 * require a lock, aside from the special case where the functions are called
 * from guc_lrc_desc_pin(). In that case it isn't possible for any other code
 * path to be executing on the context.
 */
#define SCHED_STATE_WAIT_FOR_DEREGISTER_TO_REGISTER     BIT(0)
#define SCHED_STATE_DESTROYED                           BIT(1)
#define SCHED_STATE_PENDING_DISABLE                     BIT(2)
#define SCHED_STATE_BANNED                              BIT(3)
#define SCHED_STATE_BLOCKED_SHIFT                       4
#define SCHED_STATE_BLOCKED             BIT(SCHED_STATE_BLOCKED_SHIFT)
#define SCHED_STATE_BLOCKED_MASK        (0xfff << SCHED_STATE_BLOCKED_SHIFT)
static inline void init_sched_state(struct intel_context *ce)
{
        /* Only should be called from guc_lrc_desc_pin() */
        atomic_set(&ce->guc_sched_state_no_lock, 0);
        ce->guc_state.sched_state = 0;
}

static inline bool
context_wait_for_deregister_to_register(struct intel_context *ce)
{
        return ce->guc_state.sched_state &
                SCHED_STATE_WAIT_FOR_DEREGISTER_TO_REGISTER;
}

static inline void
set_context_wait_for_deregister_to_register(struct intel_context *ce)
{
        /* Only should be called from guc_lrc_desc_pin() without lock */
        ce->guc_state.sched_state |=
                SCHED_STATE_WAIT_FOR_DEREGISTER_TO_REGISTER;
}

static inline void
clr_context_wait_for_deregister_to_register(struct intel_context *ce)
{
        lockdep_assert_held(&ce->guc_state.lock);
        ce->guc_state.sched_state &=
                ~SCHED_STATE_WAIT_FOR_DEREGISTER_TO_REGISTER;
}

static inline bool
context_destroyed(struct intel_context *ce)
{
        return ce->guc_state.sched_state & SCHED_STATE_DESTROYED;
}

static inline void
set_context_destroyed(struct intel_context *ce)
{
        lockdep_assert_held(&ce->guc_state.lock);
        ce->guc_state.sched_state |= SCHED_STATE_DESTROYED;
}

static inline bool context_pending_disable(struct intel_context *ce)
{
        return ce->guc_state.sched_state & SCHED_STATE_PENDING_DISABLE;
}

static inline void set_context_pending_disable(struct intel_context *ce)
{
        lockdep_assert_held(&ce->guc_state.lock);
        ce->guc_state.sched_state |= SCHED_STATE_PENDING_DISABLE;
}

static inline void clr_context_pending_disable(struct intel_context *ce)
{
        lockdep_assert_held(&ce->guc_state.lock);
        ce->guc_state.sched_state &= ~SCHED_STATE_PENDING_DISABLE;
}

static inline bool context_banned(struct intel_context *ce)
{
        return ce->guc_state.sched_state & SCHED_STATE_BANNED;
}

static inline void set_context_banned(struct intel_context *ce)
{
        lockdep_assert_held(&ce->guc_state.lock);
        ce->guc_state.sched_state |= SCHED_STATE_BANNED;
}

static inline void clr_context_banned(struct intel_context *ce)
{
        lockdep_assert_held(&ce->guc_state.lock);
        ce->guc_state.sched_state &= ~SCHED_STATE_BANNED;
}

static inline u32 context_blocked(struct intel_context *ce)
{
        return (ce->guc_state.sched_state & SCHED_STATE_BLOCKED_MASK) >>
                SCHED_STATE_BLOCKED_SHIFT;
}

static inline void incr_context_blocked(struct intel_context *ce)
{
        lockdep_assert_held(&ce->engine->sched_engine->lock);
        lockdep_assert_held(&ce->guc_state.lock);

        ce->guc_state.sched_state += SCHED_STATE_BLOCKED;

        GEM_BUG_ON(!context_blocked(ce));       /* Overflow check */
}

static inline void decr_context_blocked(struct intel_context *ce)
{
        lockdep_assert_held(&ce->engine->sched_engine->lock);
        lockdep_assert_held(&ce->guc_state.lock);

        GEM_BUG_ON(!context_blocked(ce));       /* Underflow check */

        ce->guc_state.sched_state -= SCHED_STATE_BLOCKED;
}

static inline bool context_guc_id_invalid(struct intel_context *ce)
{
        return ce->guc_id == GUC_INVALID_LRC_ID;
}

static inline void set_context_guc_id_invalid(struct intel_context *ce)
{
        ce->guc_id = GUC_INVALID_LRC_ID;
}

static inline struct intel_guc *ce_to_guc(struct intel_context *ce)
{
        return &ce->engine->gt->uc.guc;
}

static inline struct i915_priolist *to_priolist(struct rb_node *rb)
{
        return rb_entry(rb, struct i915_priolist, node);
}

static struct guc_lrc_desc *__get_lrc_desc(struct intel_guc *guc, u32 index)
{
        struct guc_lrc_desc *base = guc->lrc_desc_pool_vaddr;

        GEM_BUG_ON(index >= GUC_MAX_LRC_DESCRIPTORS);

        return &base[index];
}

static inline struct intel_context *__get_context(struct intel_guc *guc, u32 id)
{
        struct intel_context *ce = xa_load(&guc->context_lookup, id);

        GEM_BUG_ON(id >= GUC_MAX_LRC_DESCRIPTORS);

        return ce;
}

static int guc_lrc_desc_pool_create(struct intel_guc *guc)
{
        u32 size;
        int ret;

        size = PAGE_ALIGN(sizeof(struct guc_lrc_desc) *
                          GUC_MAX_LRC_DESCRIPTORS);
        ret = intel_guc_allocate_and_map_vma(guc, size, &guc->lrc_desc_pool,
                                             (void **)&guc->lrc_desc_pool_vaddr);
        if (ret)
                return ret;

        return 0;
}

static void guc_lrc_desc_pool_destroy(struct intel_guc *guc)
{
        guc->lrc_desc_pool_vaddr = NULL;
        i915_vma_unpin_and_release(&guc->lrc_desc_pool, I915_VMA_RELEASE_MAP);
}

static inline bool guc_submission_initialized(struct intel_guc *guc)
{
        return !!guc->lrc_desc_pool_vaddr;
}

static inline void reset_lrc_desc(struct intel_guc *guc, u32 id)
{
        if (likely(guc_submission_initialized(guc))) {
                struct guc_lrc_desc *desc = __get_lrc_desc(guc, id);
                unsigned long flags;

                memset(desc, 0, sizeof(*desc));

                /*
                 * xarray API doesn't have xa_erase_irqsave wrapper, so calling
                 * the lower level functions directly.
                 */
                xa_lock_irqsave(&guc->context_lookup, flags);
                __xa_erase(&guc->context_lookup, id);
                xa_unlock_irqrestore(&guc->context_lookup, flags);
        }
}

static inline bool lrc_desc_registered(struct intel_guc *guc, u32 id)
{
        return __get_context(guc, id);
}

static inline void set_lrc_desc_registered(struct intel_guc *guc, u32 id,
                                           struct intel_context *ce)
{
        unsigned long flags;

        /*
         * xarray API doesn't have xa_save_irqsave wrapper, so calling the
         * lower level functions directly.
         */
        xa_lock_irqsave(&guc->context_lookup, flags);
        __xa_store(&guc->context_lookup, id, ce, GFP_ATOMIC);
        xa_unlock_irqrestore(&guc->context_lookup, flags);
}

static int guc_submission_send_busy_loop(struct intel_guc *guc,
                                         const u32 *action,
                                         u32 len,
                                         u32 g2h_len_dw,
                                         bool loop)
{
        int err;

        err = intel_guc_send_busy_loop(guc, action, len, g2h_len_dw, loop);

        if (!err && g2h_len_dw)
                atomic_inc(&guc->outstanding_submission_g2h);

        return err;
}

int intel_guc_wait_for_pending_msg(struct intel_guc *guc,
                                   atomic_t *wait_var,
                                   bool interruptible,
                                   long timeout)
{
        const int state = interruptible ?
                TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;
        DEFINE_WAIT(wait);

        might_sleep();
        GEM_BUG_ON(timeout < 0);

        if (!atomic_read(wait_var))
                return 0;

        if (!timeout)
                return -ETIME;

        for (;;) {
                prepare_to_wait(&guc->ct.wq, &wait, state);

                if (!atomic_read(wait_var))
                        break;

                if (signal_pending_state(state, current)) {
                        timeout = -EINTR;
                        break;
                }

                if (!timeout) {
                        timeout = -ETIME;
                        break;
                }

                timeout = io_schedule_timeout(timeout);
        }
        finish_wait(&guc->ct.wq, &wait);

        return (timeout < 0) ? timeout : 0;
}

int intel_guc_wait_for_idle(struct intel_guc *guc, long timeout)
{
        if (!intel_uc_uses_guc_submission(&guc_to_gt(guc)->uc))
                return 0;

        return intel_guc_wait_for_pending_msg(guc,
                                              &guc->outstanding_submission_g2h,
                                              true, timeout);
}

static int guc_lrc_desc_pin(struct intel_context *ce, bool loop);

static int guc_add_request(struct intel_guc *guc, struct i915_request *rq)
{
        int err = 0;
        struct intel_context *ce = rq->context;
        u32 action[3];
        int len = 0;
        u32 g2h_len_dw = 0;
        bool enabled;

        /*
         * Corner case where requests were sitting in the priority list or a
         * request resubmitted after the context was banned.
         */
        if (unlikely(intel_context_is_banned(ce))) {
                i915_request_put(i915_request_mark_eio(rq));
                intel_engine_signal_breadcrumbs(ce->engine);
                goto out;
        }

        GEM_BUG_ON(!atomic_read(&ce->guc_id_ref));
        GEM_BUG_ON(context_guc_id_invalid(ce));

        /*
         * Corner case where the GuC firmware was blown away and reloaded while
         * this context was pinned.
         */
        if (unlikely(!lrc_desc_registered(guc, ce->guc_id))) {
                err = guc_lrc_desc_pin(ce, false);
                if (unlikely(err))
                        goto out;
        }

        /*
         * The request / context will be run on the hardware when scheduling
         * gets enabled in the unblock.
         */
        if (unlikely(context_blocked(ce)))
                goto out;

        enabled = context_enabled(ce);

        if (!enabled) {
                action[len++] = INTEL_GUC_ACTION_SCHED_CONTEXT_MODE_SET;
                action[len++] = ce->guc_id;
                action[len++] = GUC_CONTEXT_ENABLE;
                set_context_pending_enable(ce);
                intel_context_get(ce);
                g2h_len_dw = G2H_LEN_DW_SCHED_CONTEXT_MODE_SET;
        } else {
                action[len++] = INTEL_GUC_ACTION_SCHED_CONTEXT;
                action[len++] = ce->guc_id;
        }

        err = intel_guc_send_nb(guc, action, len, g2h_len_dw);
        if (!enabled && !err) {
                trace_intel_context_sched_enable(ce);
                atomic_inc(&guc->outstanding_submission_g2h);
                set_context_enabled(ce);
        } else if (!enabled) {
                clr_context_pending_enable(ce);
                intel_context_put(ce);
        }
        if (likely(!err))
                trace_i915_request_guc_submit(rq);

out:
        return err;
}

static inline void guc_set_lrc_tail(struct i915_request *rq)
{
        rq->context->lrc_reg_state[CTX_RING_TAIL] =
                intel_ring_set_tail(rq->ring, rq->tail);
}

static inline int rq_prio(const struct i915_request *rq)
{
        return rq->sched.attr.priority;
}

static int guc_dequeue_one_context(struct intel_guc *guc)
{
        struct i915_sched_engine * const sched_engine = guc->sched_engine;
        struct i915_request *last = NULL;
        bool submit = false;
        struct rb_node *rb;
        int ret;

        lockdep_assert_held(&sched_engine->lock);

        if (guc->stalled_request) {
                submit = true;
                last = guc->stalled_request;
                goto resubmit;
        }

        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) {
                        if (last && rq->context != last->context)
                                goto done;

                        list_del_init(&rq->sched.link);

                        __i915_request_submit(rq);

                        trace_i915_request_in(rq, 0);
                        last = rq;
                        submit = true;
                }

                rb_erase_cached(&p->node, &sched_engine->queue);
                i915_priolist_free(p);
        }
done:
        if (submit) {
                guc_set_lrc_tail(last);
resubmit:
                ret = guc_add_request(guc, last);
                if (unlikely(ret == -EPIPE))
                        goto deadlk;
                else if (ret == -EBUSY) {
                        tasklet_schedule(&sched_engine->tasklet);
                        guc->stalled_request = last;
                        return false;
                }
        }

        guc->stalled_request = NULL;
        return submit;

deadlk:
        sched_engine->tasklet.callback = NULL;
        tasklet_disable_nosync(&sched_engine->tasklet);
        return false;
}

static void guc_submission_tasklet(struct tasklet_struct *t)
{
        struct i915_sched_engine *sched_engine =
                from_tasklet(sched_engine, t, tasklet);
        unsigned long flags;
        bool loop;

        spin_lock_irqsave(&sched_engine->lock, flags);

        do {
                loop = guc_dequeue_one_context(sched_engine->private_data);
        } while (loop);

        i915_sched_engine_reset_on_empty(sched_engine);

        spin_unlock_irqrestore(&sched_engine->lock, flags);
}

static void cs_irq_handler(struct intel_engine_cs *engine, u16 iir)
{
        if (iir & GT_RENDER_USER_INTERRUPT)
                intel_engine_signal_breadcrumbs(engine);
}

static void __guc_context_destroy(struct intel_context *ce);
static void release_guc_id(struct intel_guc *guc, struct intel_context *ce);
static void guc_signal_context_fence(struct intel_context *ce);
static void guc_cancel_context_requests(struct intel_context *ce);
static void guc_blocked_fence_complete(struct intel_context *ce);

static void scrub_guc_desc_for_outstanding_g2h(struct intel_guc *guc)
{
        struct intel_context *ce;
        unsigned long index, flags;
        bool pending_disable, pending_enable, deregister, destroyed, banned;

        xa_for_each(&guc->context_lookup, index, ce) {
                /* Flush context */
                spin_lock_irqsave(&ce->guc_state.lock, flags);
                spin_unlock_irqrestore(&ce->guc_state.lock, flags);

                /*
                 * Once we are at this point submission_disabled() is guaranteed
                 * to be visible to all callers who set the below flags (see above
                 * flush and flushes in reset_prepare). If submission_disabled()
                 * is set, the caller shouldn't set these flags.
                 */

                destroyed = context_destroyed(ce);
                pending_enable = context_pending_enable(ce);
                pending_disable = context_pending_disable(ce);
                deregister = context_wait_for_deregister_to_register(ce);
                banned = context_banned(ce);
                init_sched_state(ce);

                if (pending_enable || destroyed || deregister) {
                        atomic_dec(&guc->outstanding_submission_g2h);
                        if (deregister)
                                guc_signal_context_fence(ce);
                        if (destroyed) {
                                release_guc_id(guc, ce);
                                __guc_context_destroy(ce);
                        }
                        if (pending_enable || deregister)
                                intel_context_put(ce);
                }

                /* Not mutualy exclusive with above if statement. */
                if (pending_disable) {
                        guc_signal_context_fence(ce);
                        if (banned) {
                                guc_cancel_context_requests(ce);
                                intel_engine_signal_breadcrumbs(ce->engine);
                        }
                        intel_context_sched_disable_unpin(ce);
                        atomic_dec(&guc->outstanding_submission_g2h);
                        spin_lock_irqsave(&ce->guc_state.lock, flags);
                        guc_blocked_fence_complete(ce);
                        spin_unlock_irqrestore(&ce->guc_state.lock, flags);

                        intel_context_put(ce);
                }
        }
}

static inline bool
submission_disabled(struct intel_guc *guc)
{
        struct i915_sched_engine * const sched_engine = guc->sched_engine;

        return unlikely(!sched_engine ||
                        !__tasklet_is_enabled(&sched_engine->tasklet));
}

static void disable_submission(struct intel_guc *guc)
{
        struct i915_sched_engine * const sched_engine = guc->sched_engine;

        if (__tasklet_is_enabled(&sched_engine->tasklet)) {
                GEM_BUG_ON(!guc->ct.enabled);
                __tasklet_disable_sync_once(&sched_engine->tasklet);
                sched_engine->tasklet.callback = NULL;
        }
}

static void enable_submission(struct intel_guc *guc)
{
        struct i915_sched_engine * const sched_engine = guc->sched_engine;
        unsigned long flags;

        spin_lock_irqsave(&guc->sched_engine->lock, flags);
        sched_engine->tasklet.callback = guc_submission_tasklet;
        wmb();  /* Make sure callback visible */
        if (!__tasklet_is_enabled(&sched_engine->tasklet) &&
            __tasklet_enable(&sched_engine->tasklet)) {
                GEM_BUG_ON(!guc->ct.enabled);

                /* And kick in case we missed a new request submission. */
                tasklet_hi_schedule(&sched_engine->tasklet);
        }
        spin_unlock_irqrestore(&guc->sched_engine->lock, flags);
}

static void guc_flush_submissions(struct intel_guc *guc)
{
        struct i915_sched_engine * const sched_engine = guc->sched_engine;
        unsigned long flags;

        spin_lock_irqsave(&sched_engine->lock, flags);
        spin_unlock_irqrestore(&sched_engine->lock, flags);
}

void intel_guc_submission_reset_prepare(struct intel_guc *guc)
{
        int i;

        if (unlikely(!guc_submission_initialized(guc))) {
                /* Reset called during driver load? GuC not yet initialised! */
                return;
        }

        intel_gt_park_heartbeats(guc_to_gt(guc));
        disable_submission(guc);
        guc->interrupts.disable(guc);

        /* Flush IRQ handler */
        spin_lock_irq(&guc_to_gt(guc)->irq_lock);
        spin_unlock_irq(&guc_to_gt(guc)->irq_lock);

        guc_flush_submissions(guc);

        /*
         * Handle any outstanding G2Hs before reset. Call IRQ handler directly
         * each pass as interrupt have been disabled. We always scrub for
         * outstanding G2H as it is possible for outstanding_submission_g2h to
         * be incremented after the context state update.
         */
        for (i = 0; i < 4 && atomic_read(&guc->outstanding_submission_g2h); ++i) {
                intel_guc_to_host_event_handler(guc);
#define wait_for_reset(guc, wait_var) \
                intel_guc_wait_for_pending_msg(guc, wait_var, false, (HZ / 20))
                do {
                        wait_for_reset(guc, &guc->outstanding_submission_g2h);
                } while (!list_empty(&guc->ct.requests.incoming));
        }
        scrub_guc_desc_for_outstanding_g2h(guc);
}

static struct intel_engine_cs *
guc_virtual_get_sibling(struct intel_engine_cs *ve, unsigned int sibling)
{
        struct intel_engine_cs *engine;
        intel_engine_mask_t tmp, mask = ve->mask;
        unsigned int num_siblings = 0;

        for_each_engine_masked(engine, ve->gt, mask, tmp)
                if (num_siblings++ == sibling)
                        return engine;

        return NULL;
}

static inline struct intel_engine_cs *
__context_to_physical_engine(struct intel_context *ce)
{
        struct intel_engine_cs *engine = ce->engine;

        if (intel_engine_is_virtual(engine))
                engine = guc_virtual_get_sibling(engine, 0);

        return engine;
}

static void guc_reset_state(struct intel_context *ce, u32 head, bool scrub)
{
        struct intel_engine_cs *engine = __context_to_physical_engine(ce);

        if (intel_context_is_banned(ce))
                return;

        GEM_BUG_ON(!intel_context_is_pinned(ce));

        /*
         * 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.
         */
        if (scrub)
                lrc_init_regs(ce, engine, true);

        /* Rerun the request; its payload has been neutered (if guilty). */
        lrc_update_regs(ce, engine, head);
}

static void guc_reset_nop(struct intel_engine_cs *engine)
{
}

static void guc_rewind_nop(struct intel_engine_cs *engine, bool stalled)
{
}

static void
__unwind_incomplete_requests(struct intel_context *ce)
{
        struct i915_request *rq, *rn;
        struct list_head *pl;
        int prio = I915_PRIORITY_INVALID;
        struct i915_sched_engine * const sched_engine =
                ce->engine->sched_engine;
        unsigned long flags;

        spin_lock_irqsave(&sched_engine->lock, flags);
        spin_lock(&ce->guc_active.lock);
        list_for_each_entry_safe(rq, rn,
                                 &ce->guc_active.requests,
                                 sched.link) {
                if (i915_request_completed(rq))
                        continue;

                list_del_init(&rq->sched.link);
                spin_unlock(&ce->guc_active.lock);

                __i915_request_unsubmit(rq);

                /* Push the request back into the queue for later resubmission. */
                GEM_BUG_ON(rq_prio(rq) == I915_PRIORITY_INVALID);
                if (rq_prio(rq) != prio) {
                        prio = rq_prio(rq);
                        pl = i915_sched_lookup_priolist(sched_engine, prio);
                }
                GEM_BUG_ON(i915_sched_engine_is_empty(sched_engine));

                list_add_tail(&rq->sched.link, pl);
                set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);

                spin_lock(&ce->guc_active.lock);
        }
        spin_unlock(&ce->guc_active.lock);
        spin_unlock_irqrestore(&sched_engine->lock, flags);
}

static void __guc_reset_context(struct intel_context *ce, bool stalled)
{
        struct i915_request *rq;
        u32 head;

        intel_context_get(ce);

        /*
         * GuC will implicitly mark the context as non-schedulable
         * when it sends the reset notification. Make sure our state
         * reflects this change. The context will be marked enabled
         * on resubmission.
         */
        clr_context_enabled(ce);

        rq = intel_context_find_active_request(ce);
        if (!rq) {
                head = ce->ring->tail;
                stalled = false;
                goto out_replay;
        }

        if (!i915_request_started(rq))
                stalled = false;

        GEM_BUG_ON(i915_active_is_idle(&ce->active));
        head = intel_ring_wrap(ce->ring, rq->head);
        __i915_request_reset(rq, stalled);

out_replay:
        guc_reset_state(ce, head, stalled);
        __unwind_incomplete_requests(ce);
        intel_context_put(ce);
}

void intel_guc_submission_reset(struct intel_guc *guc, bool stalled)
{
        struct intel_context *ce;
        unsigned long index;

        if (unlikely(!guc_submission_initialized(guc))) {
                /* Reset called during driver load? GuC not yet initialised! */
                return;
        }

        xa_for_each(&guc->context_lookup, index, ce)
                if (intel_context_is_pinned(ce))
                        __guc_reset_context(ce, stalled);

        /* GuC is blown away, drop all references to contexts */
        xa_destroy(&guc->context_lookup);
}

static void guc_cancel_context_requests(struct intel_context *ce)
{
        struct i915_sched_engine *sched_engine = ce_to_guc(ce)->sched_engine;
        struct i915_request *rq;
        unsigned long flags;

        /* Mark all executing requests as skipped. */
        spin_lock_irqsave(&sched_engine->lock, flags);
        spin_lock(&ce->guc_active.lock);
        list_for_each_entry(rq, &ce->guc_active.requests, sched.link)
                i915_request_put(i915_request_mark_eio(rq));
        spin_unlock(&ce->guc_active.lock);
        spin_unlock_irqrestore(&sched_engine->lock, flags);
}

static void
guc_cancel_sched_engine_requests(struct i915_sched_engine *sched_engine)
{
        struct i915_request *rq, *rn;
        struct rb_node *rb;
        unsigned long flags;

        /* Can be called during boot if GuC fails to load */
        if (!sched_engine)
                return;

        /*
         * 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.)
         */
        spin_lock_irqsave(&sched_engine->lock, flags);

        /* 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) {
                        list_del_init(&rq->sched.link);

                        __i915_request_submit(rq);

                        i915_request_put(i915_request_mark_eio(rq));
                }

                rb_erase_cached(&p->node, &sched_engine->queue);
                i915_priolist_free(p);
        }

        /* Remaining _unready_ requests will be nop'ed when submitted */

        sched_engine->queue_priority_hint = INT_MIN;
        sched_engine->queue = RB_ROOT_CACHED;

        spin_unlock_irqrestore(&sched_engine->lock, flags);
}

void intel_guc_submission_cancel_requests(struct intel_guc *guc)
{
        struct intel_context *ce;
        unsigned long index;

        xa_for_each(&guc->context_lookup, index, ce)
                if (intel_context_is_pinned(ce))
                        guc_cancel_context_requests(ce);

        guc_cancel_sched_engine_requests(guc->sched_engine);

        /* GuC is blown away, drop all references to contexts */
        xa_destroy(&guc->context_lookup);
}

void intel_guc_submission_reset_finish(struct intel_guc *guc)
{
        /* Reset called during driver load or during wedge? */
        if (unlikely(!guc_submission_initialized(guc) ||
                     test_bit(I915_WEDGED, &guc_to_gt(guc)->reset.flags))) {
                return;
        }

        /*
         * Technically possible for either of these values to be non-zero here,
         * but very unlikely + harmless. Regardless let's add a warn so we can
         * see in CI if this happens frequently / a precursor to taking down the
         * machine.
         */
        GEM_WARN_ON(atomic_read(&guc->outstanding_submission_g2h));
        atomic_set(&guc->outstanding_submission_g2h, 0);

        intel_guc_global_policies_update(guc);
        enable_submission(guc);
        intel_gt_unpark_heartbeats(guc_to_gt(guc));
}

/*
 * Set up the memory resources to be shared with the GuC (via the GGTT)
 * at firmware loading time.
 */
int intel_guc_submission_init(struct intel_guc *guc)
{
        int ret;

        if (guc->lrc_desc_pool)
                return 0;

        ret = guc_lrc_desc_pool_create(guc);
        if (ret)
                return ret;
        /*
         * Keep static analysers happy, let them know that we allocated the
         * vma after testing that it didn't exist earlier.

         */
        GEM_BUG_ON(!guc->lrc_desc_pool);

        xa_init_flags(&guc->context_lookup, XA_FLAGS_LOCK_IRQ);

        spin_lock_init(&guc->contexts_lock);
        INIT_LIST_HEAD(&guc->guc_id_list);
        ida_init(&guc->guc_ids);

        return 0;
}

void intel_guc_submission_fini(struct intel_guc *guc)
{
        if (!guc->lrc_desc_pool)
                return;

        guc_lrc_desc_pool_destroy(guc);
        i915_sched_engine_put(guc->sched_engine);
}

static inline void queue_request(struct i915_sched_engine *sched_engine,
                                 struct i915_request *rq,
                                 int prio)
{
        GEM_BUG_ON(!list_empty(&rq->sched.link));
        list_add_tail(&rq->sched.link,
                      i915_sched_lookup_priolist(sched_engine, prio));
        set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
}

static int guc_bypass_tasklet_submit(struct intel_guc *guc,
                                     struct i915_request *rq)
{
        int ret;

        __i915_request_submit(rq);

        trace_i915_request_in(rq, 0);

        guc_set_lrc_tail(rq);
        ret = guc_add_request(guc, rq);
        if (ret == -EBUSY)
                guc->stalled_request = rq;

        if (unlikely(ret == -EPIPE))
                disable_submission(guc);

        return ret;
}

static void guc_submit_request(struct i915_request *rq)
{
        struct i915_sched_engine *sched_engine = rq->engine->sched_engine;
        struct intel_guc *guc = &rq->engine->gt->uc.guc;
        unsigned long flags;

        /* Will be called from irq-context when using foreign fences. */
        spin_lock_irqsave(&sched_engine->lock, flags);

        if (submission_disabled(guc) || guc->stalled_request ||
            !i915_sched_engine_is_empty(sched_engine))
                queue_request(sched_engine, rq, rq_prio(rq));
        else if (guc_bypass_tasklet_submit(guc, rq) == -EBUSY)
                tasklet_hi_schedule(&sched_engine->tasklet);

        spin_unlock_irqrestore(&sched_engine->lock, flags);
}

static int new_guc_id(struct intel_guc *guc)
{
        return ida_simple_get(&guc->guc_ids, 0,
                              GUC_MAX_LRC_DESCRIPTORS, GFP_KERNEL |
                              __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
}

static void __release_guc_id(struct intel_guc *guc, struct intel_context *ce)
{
        if (!context_guc_id_invalid(ce)) {
                ida_simple_remove(&guc->guc_ids, ce->guc_id);
                reset_lrc_desc(guc, ce->guc_id);
                set_context_guc_id_invalid(ce);
        }
        if (!list_empty(&ce->guc_id_link))
                list_del_init(&ce->guc_id_link);
}

static void release_guc_id(struct intel_guc *guc, struct intel_context *ce)
{
        unsigned long flags;

        spin_lock_irqsave(&guc->contexts_lock, flags);
        __release_guc_id(guc, ce);
        spin_unlock_irqrestore(&guc->contexts_lock, flags);
}

static int steal_guc_id(struct intel_guc *guc)
{
        struct intel_context *ce;
        int guc_id;

        lockdep_assert_held(&guc->contexts_lock);

        if (!list_empty(&guc->guc_id_list)) {
                ce = list_first_entry(&guc->guc_id_list,
                                      struct intel_context,
                                      guc_id_link);

                GEM_BUG_ON(atomic_read(&ce->guc_id_ref));
                GEM_BUG_ON(context_guc_id_invalid(ce));

                list_del_init(&ce->guc_id_link);
                guc_id = ce->guc_id;
                clr_context_registered(ce);
                set_context_guc_id_invalid(ce);
                return guc_id;
        } else {
                return -EAGAIN;
        }
}

static int assign_guc_id(struct intel_guc *guc, u16 *out)
{
        int ret;

        lockdep_assert_held(&guc->contexts_lock);

        ret = new_guc_id(guc);
        if (unlikely(ret < 0)) {
                ret = steal_guc_id(guc);
                if (ret < 0)
                        return ret;
        }

        *out = ret;
        return 0;
}

#define PIN_GUC_ID_TRIES        4
static int pin_guc_id(struct intel_guc *guc, struct intel_context *ce)
{
        int ret = 0;
        unsigned long flags, tries = PIN_GUC_ID_TRIES;

        GEM_BUG_ON(atomic_read(&ce->guc_id_ref));

try_again:
        spin_lock_irqsave(&guc->contexts_lock, flags);

        if (context_guc_id_invalid(ce)) {
                ret = assign_guc_id(guc, &ce->guc_id);
                if (ret)
                        goto out_unlock;
                ret = 1;        /* Indidcates newly assigned guc_id */
        }
        if (!list_empty(&ce->guc_id_link))
                list_del_init(&ce->guc_id_link);
        atomic_inc(&ce->guc_id_ref);

out_unlock:
        spin_unlock_irqrestore(&guc->contexts_lock, flags);

        /*
         * -EAGAIN indicates no guc_ids are available, let's retire any
         * outstanding requests to see if that frees up a guc_id. If the first
         * retire didn't help, insert a sleep with the timeslice duration before
         * attempting to retire more requests. Double the sleep period each
         * subsequent pass before finally giving up. The sleep period has max of
         * 100ms and minimum of 1ms.
         */
        if (ret == -EAGAIN && --tries) {
                if (PIN_GUC_ID_TRIES - tries > 1) {
                        unsigned int timeslice_shifted =
                                ce->engine->props.timeslice_duration_ms <<
                                (PIN_GUC_ID_TRIES - tries - 2);
                        unsigned int max = min_t(unsigned int, 100,
                                                 timeslice_shifted);

                        msleep(max_t(unsigned int, max, 1));
                }
                intel_gt_retire_requests(guc_to_gt(guc));
                goto try_again;
        }

        return ret;
}

static void unpin_guc_id(struct intel_guc *guc, struct intel_context *ce)
{
        unsigned long flags;

        GEM_BUG_ON(atomic_read(&ce->guc_id_ref) < 0);

        if (unlikely(context_guc_id_invalid(ce)))
                return;

        spin_lock_irqsave(&guc->contexts_lock, flags);
        if (!context_guc_id_invalid(ce) && list_empty(&ce->guc_id_link) &&
            !atomic_read(&ce->guc_id_ref))
                list_add_tail(&ce->guc_id_link, &guc->guc_id_list);
        spin_unlock_irqrestore(&guc->contexts_lock, flags);
}

static int __guc_action_register_context(struct intel_guc *guc,
                                         u32 guc_id,
                                         u32 offset,
                                         bool loop)
{
        u32 action[] = {
                INTEL_GUC_ACTION_REGISTER_CONTEXT,
                guc_id,
                offset,
        };

        return guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action),
                                             0, loop);
}

static int register_context(struct intel_context *ce, bool loop)
{
        struct intel_guc *guc = ce_to_guc(ce);
        u32 offset = intel_guc_ggtt_offset(guc, guc->lrc_desc_pool) +
                ce->guc_id * sizeof(struct guc_lrc_desc);
        int ret;

        trace_intel_context_register(ce);

        ret = __guc_action_register_context(guc, ce->guc_id, offset, loop);
        if (likely(!ret))
                set_context_registered(ce);

        return ret;
}

static int __guc_action_deregister_context(struct intel_guc *guc,
                                           u32 guc_id,
                                           bool loop)
{
        u32 action[] = {
                INTEL_GUC_ACTION_DEREGISTER_CONTEXT,
                guc_id,
        };

        return guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action),
                                             G2H_LEN_DW_DEREGISTER_CONTEXT,
                                             loop);
}

static int deregister_context(struct intel_context *ce, u32 guc_id, bool loop)
{
        struct intel_guc *guc = ce_to_guc(ce);

        trace_intel_context_deregister(ce);

        return __guc_action_deregister_context(guc, guc_id, loop);
}

static intel_engine_mask_t adjust_engine_mask(u8 class, intel_engine_mask_t mask)
{
        switch (class) {
        case RENDER_CLASS:
                return mask >> RCS0;
        case VIDEO_ENHANCEMENT_CLASS:
                return mask >> VECS0;
        case VIDEO_DECODE_CLASS:
                return mask >> VCS0;
        case COPY_ENGINE_CLASS:
                return mask >> BCS0;
        default:
                MISSING_CASE(class);
                return 0;
        }
}

static void guc_context_policy_init(struct intel_engine_cs *engine,
                                    struct guc_lrc_desc *desc)
{
        desc->policy_flags = 0;

        if (engine->flags & I915_ENGINE_WANT_FORCED_PREEMPTION)
                desc->policy_flags |= CONTEXT_POLICY_FLAG_PREEMPT_TO_IDLE;

        /* NB: For both of these, zero means disabled. */
        desc->execution_quantum = engine->props.timeslice_duration_ms * 1000;
        desc->preemption_timeout = engine->props.preempt_timeout_ms * 1000;
}

static inline u8 map_i915_prio_to_guc_prio(int prio);

static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
{
        struct intel_engine_cs *engine = ce->engine;
        struct intel_runtime_pm *runtime_pm = engine->uncore->rpm;
        struct intel_guc *guc = &engine->gt->uc.guc;
        u32 desc_idx = ce->guc_id;
        struct guc_lrc_desc *desc;
        const struct i915_gem_context *ctx;
        int prio = I915_CONTEXT_DEFAULT_PRIORITY;
        bool context_registered;
        intel_wakeref_t wakeref;
        int ret = 0;

        GEM_BUG_ON(!engine->mask);

        /*
         * Ensure LRC + CT vmas are is same region as write barrier is done
         * based on CT vma region.
         */
        GEM_BUG_ON(i915_gem_object_is_lmem(guc->ct.vma->obj) !=
                   i915_gem_object_is_lmem(ce->ring->vma->obj));

        context_registered = lrc_desc_registered(guc, desc_idx);

        rcu_read_lock();
        ctx = rcu_dereference(ce->gem_context);
        if (ctx)
                prio = ctx->sched.priority;
        rcu_read_unlock();

        reset_lrc_desc(guc, desc_idx);
        set_lrc_desc_registered(guc, desc_idx, ce);

        desc = __get_lrc_desc(guc, desc_idx);
        desc->engine_class = engine_class_to_guc_class(engine->class);
        desc->engine_submit_mask = adjust_engine_mask(engine->class,
                                                      engine->mask);
        desc->hw_context_desc = ce->lrc.lrca;
        ce->guc_prio = map_i915_prio_to_guc_prio(prio);
        desc->priority = ce->guc_prio;
        desc->context_flags = CONTEXT_REGISTRATION_FLAG_KMD;
        guc_context_policy_init(engine, desc);
        init_sched_state(ce);

        /*
         * The context_lookup xarray is used to determine if the hardware
         * context is currently registered. There are two cases in which it
         * could be registered either the guc_id has been stolen from another
         * context or the lrc descriptor address of this context has changed. In
         * either case the context needs to be deregistered with the GuC before
         * registering this context.
         */
        if (context_registered) {
                trace_intel_context_steal_guc_id(ce);
                if (!loop) {
                        set_context_wait_for_deregister_to_register(ce);
                        intel_context_get(ce);
                } else {
                        bool disabled;
                        unsigned long flags;

                        /* Seal race with Reset */
                        spin_lock_irqsave(&ce->guc_state.lock, flags);
                        disabled = submission_disabled(guc);
                        if (likely(!disabled)) {
                                set_context_wait_for_deregister_to_register(ce);
                                intel_context_get(ce);
                        }
                        spin_unlock_irqrestore(&ce->guc_state.lock, flags);
                        if (unlikely(disabled)) {
                                reset_lrc_desc(guc, desc_idx);
                                return 0;       /* Will get registered later */
                        }
                }

                /*
                 * If stealing the guc_id, this ce has the same guc_id as the
                 * context whose guc_id was stolen.
                 */
                with_intel_runtime_pm(runtime_pm, wakeref)
                        ret = deregister_context(ce, ce->guc_id, loop);
                if (unlikely(ret == -EBUSY)) {
                        clr_context_wait_for_deregister_to_register(ce);
                        intel_context_put(ce);
                } else if (unlikely(ret == -ENODEV)) {
                        ret = 0;        /* Will get registered later */
                }
        } else {
                with_intel_runtime_pm(runtime_pm, wakeref)
                        ret = register_context(ce, loop);
                if (unlikely(ret == -EBUSY))
                        reset_lrc_desc(guc, desc_idx);
                else if (unlikely(ret == -ENODEV))
                        ret = 0;        /* Will get registered later */
        }

        return ret;
}

static int __guc_context_pre_pin(struct intel_context *ce,
                                 struct intel_engine_cs *engine,
                                 struct i915_gem_ww_ctx *ww,
                                 void **vaddr)
{
        return lrc_pre_pin(ce, engine, ww, vaddr);
}

static int __guc_context_pin(struct intel_context *ce,
                             struct intel_engine_cs *engine,
                             void *vaddr)
{
        if (i915_ggtt_offset(ce->state) !=
            (ce->lrc.lrca & CTX_GTT_ADDRESS_MASK))
                set_bit(CONTEXT_LRCA_DIRTY, &ce->flags);

        /*
         * GuC context gets pinned in guc_request_alloc. See that function for
         * explaination of why.
         */

        return lrc_pin(ce, engine, vaddr);
}

static int guc_context_pre_pin(struct intel_context *ce,
                               struct i915_gem_ww_ctx *ww,
                               void **vaddr)
{
        return __guc_context_pre_pin(ce, ce->engine, ww, vaddr);
}

static int guc_context_pin(struct intel_context *ce, void *vaddr)
{
        return __guc_context_pin(ce, ce->engine, vaddr);
}

static void guc_context_unpin(struct intel_context *ce)
{
        struct intel_guc *guc = ce_to_guc(ce);

        unpin_guc_id(guc, ce);
        lrc_unpin(ce);
}

static void guc_context_post_unpin(struct intel_context *ce)
{
        lrc_post_unpin(ce);
}

static void __guc_context_sched_enable(struct intel_guc *guc,
                                       struct intel_context *ce)
{
        u32 action[] = {
                INTEL_GUC_ACTION_SCHED_CONTEXT_MODE_SET,
                ce->guc_id,
                GUC_CONTEXT_ENABLE
        };

        trace_intel_context_sched_enable(ce);

        guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action),
                                      G2H_LEN_DW_SCHED_CONTEXT_MODE_SET, true);
}

static void __guc_context_sched_disable(struct intel_guc *guc,
                                        struct intel_context *ce,
                                        u16 guc_id)
{
        u32 action[] = {
                INTEL_GUC_ACTION_SCHED_CONTEXT_MODE_SET,
                guc_id, /* ce->guc_id not stable */
                GUC_CONTEXT_DISABLE
        };

        GEM_BUG_ON(guc_id == GUC_INVALID_LRC_ID);

        trace_intel_context_sched_disable(ce);

        guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action),
                                      G2H_LEN_DW_SCHED_CONTEXT_MODE_SET, true);
}

static void guc_blocked_fence_complete(struct intel_context *ce)
{
        lockdep_assert_held(&ce->guc_state.lock);

        if (!i915_sw_fence_done(&ce->guc_blocked))
                i915_sw_fence_complete(&ce->guc_blocked);
}

static void guc_blocked_fence_reinit(struct intel_context *ce)
{
        lockdep_assert_held(&ce->guc_state.lock);
        GEM_BUG_ON(!i915_sw_fence_done(&ce->guc_blocked));

        /*
         * This fence is always complete unless a pending schedule disable is
         * outstanding. We arm the fence here and complete it when we receive
         * the pending schedule disable complete message.
         */
        i915_sw_fence_fini(&ce->guc_blocked);
        i915_sw_fence_reinit(&ce->guc_blocked);
        i915_sw_fence_await(&ce->guc_blocked);
        i915_sw_fence_commit(&ce->guc_blocked);
}

static u16 prep_context_pending_disable(struct intel_context *ce)
{
        lockdep_assert_held(&ce->guc_state.lock);

        set_context_pending_disable(ce);
        clr_context_enabled(ce);
        guc_blocked_fence_reinit(ce);
        intel_context_get(ce);

        return ce->guc_id;
}

static struct i915_sw_fence *guc_context_block(struct intel_context *ce)
{
        struct intel_guc *guc = ce_to_guc(ce);
        struct i915_sched_engine *sched_engine = ce->engine->sched_engine;
        unsigned long flags;
        struct intel_runtime_pm *runtime_pm = ce->engine->uncore->rpm;
        intel_wakeref_t wakeref;
        u16 guc_id;
        bool enabled;

        spin_lock_irqsave(&ce->guc_state.lock, flags);

        /*
         * Sync with submission path, increment before below changes to context
         * state.
         */
        spin_lock(&sched_engine->lock);
        incr_context_blocked(ce);
        spin_unlock(&sched_engine->lock);

        enabled = context_enabled(ce);
        if (unlikely(!enabled || submission_disabled(guc))) {
                if (enabled)
                        clr_context_enabled(ce);
                spin_unlock_irqrestore(&ce->guc_state.lock, flags);
                return &ce->guc_blocked;
        }

        /*
         * We add +2 here as the schedule disable complete CTB handler calls
         * intel_context_sched_disable_unpin (-2 to pin_count).
         */
        atomic_add(2, &ce->pin_count);

        guc_id = prep_context_pending_disable(ce);

        spin_unlock_irqrestore(&ce->guc_state.lock, flags);

        with_intel_runtime_pm(runtime_pm, wakeref)
                __guc_context_sched_disable(guc, ce, guc_id);

        return &ce->guc_blocked;
}

static void guc_context_unblock(struct intel_context *ce)
{
        struct intel_guc *guc = ce_to_guc(ce);
        struct i915_sched_engine *sched_engine = ce->engine->sched_engine;
        unsigned long flags;
        struct intel_runtime_pm *runtime_pm = ce->engine->uncore->rpm;
        intel_wakeref_t wakeref;
        bool enable;

        GEM_BUG_ON(context_enabled(ce));

        spin_lock_irqsave(&ce->guc_state.lock, flags);

        if (unlikely(submission_disabled(guc) ||
                     !intel_context_is_pinned(ce) ||
                     context_pending_disable(ce) ||
                     context_blocked(ce) > 1)) {
                enable = false;
        } else {
                enable = true;
                set_context_pending_enable(ce);
                set_context_enabled(ce);
                intel_context_get(ce);
        }

        /*
         * Sync with submission path, decrement after above changes to context
         * state.
         */
        spin_lock(&sched_engine->lock);
        decr_context_blocked(ce);
        spin_unlock(&sched_engine->lock);

        spin_unlock_irqrestore(&ce->guc_state.lock, flags);

        if (enable) {
                with_intel_runtime_pm(runtime_pm, wakeref)
                        __guc_context_sched_enable(guc, ce);
        }
}

static void guc_context_cancel_request(struct intel_context *ce,
                                       struct i915_request *rq)
{
        if (i915_sw_fence_signaled(&rq->submit)) {
                struct i915_sw_fence *fence = guc_context_block(ce);

                i915_sw_fence_wait(fence);
                if (!i915_request_completed(rq)) {
                        __i915_request_skip(rq);
                        guc_reset_state(ce, intel_ring_wrap(ce->ring, rq->head),
                                        true);
                }
                guc_context_unblock(ce);
        }
}

static void __guc_context_set_preemption_timeout(struct intel_guc *guc,
                                                 u16 guc_id,
                                                 u32 preemption_timeout)
{
        u32 action[] = {
                INTEL_GUC_ACTION_SET_CONTEXT_PREEMPTION_TIMEOUT,
                guc_id,
                preemption_timeout
        };

        intel_guc_send_busy_loop(guc, action, ARRAY_SIZE(action), 0, true);
}

static void guc_context_ban(struct intel_context *ce, struct i915_request *rq)
{
        struct intel_guc *guc = ce_to_guc(ce);
        struct intel_runtime_pm *runtime_pm =
                &ce->engine->gt->i915->runtime_pm;
        intel_wakeref_t wakeref;
        unsigned long flags;

        guc_flush_submissions(guc);

        spin_lock_irqsave(&ce->guc_state.lock, flags);
        set_context_banned(ce);

        if (submission_disabled(guc) ||
            (!context_enabled(ce) && !context_pending_disable(ce))) {
                spin_unlock_irqrestore(&ce->guc_state.lock, flags);

                guc_cancel_context_requests(ce);
                intel_engine_signal_breadcrumbs(ce->engine);
        } else if (!context_pending_disable(ce)) {
                u16 guc_id;

                /*
                 * We add +2 here as the schedule disable complete CTB handler
                 * calls intel_context_sched_disable_unpin (-2 to pin_count).
                 */
                atomic_add(2, &ce->pin_count);

                guc_id = prep_context_pending_disable(ce);
                spin_unlock_irqrestore(&ce->guc_state.lock, flags);

                /*
                 * In addition to disabling scheduling, set the preemption
                 * timeout to the minimum value (1 us) so the banned context
                 * gets kicked off the HW ASAP.
                 */
                with_intel_runtime_pm(runtime_pm, wakeref) {
                        __guc_context_set_preemption_timeout(guc, guc_id, 1);
                        __guc_context_sched_disable(guc, ce, guc_id);
                }
        } else {
                if (!context_guc_id_invalid(ce))
                        with_intel_runtime_pm(runtime_pm, wakeref)
                                __guc_context_set_preemption_timeout(guc,
                                                                     ce->guc_id,
                                                                     1);
                spin_unlock_irqrestore(&ce->guc_state.lock, flags);
        }
}

static void guc_context_sched_disable(struct intel_context *ce)
{
        struct intel_guc *guc = ce_to_guc(ce);
        unsigned long flags;
        struct intel_runtime_pm *runtime_pm = &ce->engine->gt->i915->runtime_pm;
        intel_wakeref_t wakeref;
        u16 guc_id;
        bool enabled;

        if (submission_disabled(guc) || context_guc_id_invalid(ce) ||
            !lrc_desc_registered(guc, ce->guc_id)) {
                clr_context_enabled(ce);
                goto unpin;
        }

        if (!context_enabled(ce))
                goto unpin;

        spin_lock_irqsave(&ce->guc_state.lock, flags);

        /*
         * We have to check if the context has been disabled by another thread.
         * We also have to check if the context has been pinned again as another
         * pin operation is allowed to pass this function. Checking the pin
         * count, within ce->guc_state.lock, synchronizes this function with
         * guc_request_alloc ensuring a request doesn't slip through the
         * 'context_pending_disable' fence. Checking within the spin lock (can't
         * sleep) ensures another process doesn't pin this context and generate
         * a request before we set the 'context_pending_disable' flag here.
         */
        enabled = context_enabled(ce);
        if (unlikely(!enabled || submission_disabled(guc))) {
                if (enabled)
                        clr_context_enabled(ce);
                spin_unlock_irqrestore(&ce->guc_state.lock, flags);
                goto unpin;
        }
        if (unlikely(atomic_add_unless(&ce->pin_count, -2, 2))) {
                spin_unlock_irqrestore(&ce->guc_state.lock, flags);
                return;
        }
        guc_id = prep_context_pending_disable(ce);

        spin_unlock_irqrestore(&ce->guc_state.lock, flags);

        with_intel_runtime_pm(runtime_pm, wakeref)
                __guc_context_sched_disable(guc, ce, guc_id);

        return;
unpin:
        intel_context_sched_disable_unpin(ce);
}

static inline void guc_lrc_desc_unpin(struct intel_context *ce)
{
        struct intel_guc *guc = ce_to_guc(ce);

        GEM_BUG_ON(!lrc_desc_registered(guc, ce->guc_id));
        GEM_BUG_ON(ce != __get_context(guc, ce->guc_id));
        GEM_BUG_ON(context_enabled(ce));

        clr_context_registered(ce);
        deregister_context(ce, ce->guc_id, true);
}

static void __guc_context_destroy(struct intel_context *ce)
{
        GEM_BUG_ON(ce->guc_prio_count[GUC_CLIENT_PRIORITY_KMD_HIGH] ||
                   ce->guc_prio_count[GUC_CLIENT_PRIORITY_HIGH] ||
                   ce->guc_prio_count[GUC_CLIENT_PRIORITY_KMD_NORMAL] ||
                   ce->guc_prio_count[GUC_CLIENT_PRIORITY_NORMAL]);

        lrc_fini(ce);
        intel_context_fini(ce);

        if (intel_engine_is_virtual(ce->engine)) {
                struct guc_virtual_engine *ve =
                        container_of(ce, typeof(*ve), context);

                if (ve->base.breadcrumbs)
                        intel_breadcrumbs_put(ve->base.breadcrumbs);

                kfree(ve);
        } else {
                intel_context_free(ce);
        }
}

static void guc_context_destroy(struct kref *kref)
{
        struct intel_context *ce = container_of(kref, typeof(*ce), ref);
        struct intel_runtime_pm *runtime_pm = ce->engine->uncore->rpm;
        struct intel_guc *guc = ce_to_guc(ce);
        intel_wakeref_t wakeref;
        unsigned long flags;
        bool disabled;

        /*
         * If the guc_id is invalid this context has been stolen and we can free
         * it immediately. Also can be freed immediately if the context is not
         * registered with the GuC or the GuC is in the middle of a reset.
         */
        if (context_guc_id_invalid(ce)) {
                __guc_context_destroy(ce);
                return;
        } else if (submission_disabled(guc) ||
                   !lrc_desc_registered(guc, ce->guc_id)) {
                release_guc_id(guc, ce);
                __guc_context_destroy(ce);
                return;
        }

        /*
         * We have to acquire the context spinlock and check guc_id again, if it
         * is valid it hasn't been stolen and needs to be deregistered. We
         * delete this context from the list of unpinned guc_ids available to
         * steal to seal a race with guc_lrc_desc_pin(). When the G2H CTB
         * returns indicating this context has been deregistered the guc_id is
         * returned to the pool of available guc_ids.
         */
        spin_lock_irqsave(&guc->contexts_lock, flags);
        if (context_guc_id_invalid(ce)) {
                spin_unlock_irqrestore(&guc->contexts_lock, flags);
                __guc_context_destroy(ce);
                return;
        }

        if (!list_empty(&ce->guc_id_link))
                list_del_init(&ce->guc_id_link);
        spin_unlock_irqrestore(&guc->contexts_lock, flags);

        /* Seal race with Reset */
        spin_lock_irqsave(&ce->guc_state.lock, flags);
        disabled = submission_disabled(guc);
        if (likely(!disabled))
                set_context_destroyed(ce);
        spin_unlock_irqrestore(&ce->guc_state.lock, flags);
        if (unlikely(disabled)) {
                release_guc_id(guc, ce);
                __guc_context_destroy(ce);
                return;
        }

        /*
         * We defer GuC context deregistration until the context is destroyed
         * in order to save on CTBs. With this optimization ideally we only need
         * 1 CTB to register the context during the first pin and 1 CTB to
         * deregister the context when the context is destroyed. Without this
         * optimization, a CTB would be needed every pin & unpin.
         *
         * XXX: Need to acqiure the runtime wakeref as this can be triggered
         * from context_free_worker when runtime wakeref is not held.
         * guc_lrc_desc_unpin requires the runtime as a GuC register is written
         * in H2G CTB to deregister the context. A future patch may defer this
         * H2G CTB if the runtime wakeref is zero.
         */
        with_intel_runtime_pm(runtime_pm, wakeref)
                guc_lrc_desc_unpin(ce);
}

static int guc_context_alloc(struct intel_context *ce)
{
        return lrc_alloc(ce, ce->engine);
}

static void guc_context_set_prio(struct intel_guc *guc,
                                 struct intel_context *ce,
                                 u8 prio)
{
        u32 action[] = {
                INTEL_GUC_ACTION_SET_CONTEXT_PRIORITY,
                ce->guc_id,
                prio,
        };

        GEM_BUG_ON(prio < GUC_CLIENT_PRIORITY_KMD_HIGH ||
                   prio > GUC_CLIENT_PRIORITY_NORMAL);

        if (ce->guc_prio == prio || submission_disabled(guc) ||
            !context_registered(ce))
                return;

        guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action), 0, true);

        ce->guc_prio = prio;
        trace_intel_context_set_prio(ce);
}

static inline u8 map_i915_prio_to_guc_prio(int prio)
{
        if (prio == I915_PRIORITY_NORMAL)
                return GUC_CLIENT_PRIORITY_KMD_NORMAL;
        else if (prio < I915_PRIORITY_NORMAL)
                return GUC_CLIENT_PRIORITY_NORMAL;
        else if (prio < I915_PRIORITY_DISPLAY)
                return GUC_CLIENT_PRIORITY_HIGH;
        else
                return GUC_CLIENT_PRIORITY_KMD_HIGH;
}

static inline void add_context_inflight_prio(struct intel_context *ce,
                                             u8 guc_prio)
{
        lockdep_assert_held(&ce->guc_active.lock);
        GEM_BUG_ON(guc_prio >= ARRAY_SIZE(ce->guc_prio_count));

        ++ce->guc_prio_count[guc_prio];

        /* Overflow protection */
        GEM_WARN_ON(!ce->guc_prio_count[guc_prio]);
}

static inline void sub_context_inflight_prio(struct intel_context *ce,
                                             u8 guc_prio)
{
        lockdep_assert_held(&ce->guc_active.lock);
        GEM_BUG_ON(guc_prio >= ARRAY_SIZE(ce->guc_prio_count));

        /* Underflow protection */
        GEM_WARN_ON(!ce->guc_prio_count[guc_prio]);

        --ce->guc_prio_count[guc_prio];
}

static inline void update_context_prio(struct intel_context *ce)
{
        struct intel_guc *guc = &ce->engine->gt->uc.guc;
        int i;

        BUILD_BUG_ON(GUC_CLIENT_PRIORITY_KMD_HIGH != 0);
        BUILD_BUG_ON(GUC_CLIENT_PRIORITY_KMD_HIGH > GUC_CLIENT_PRIORITY_NORMAL);

        lockdep_assert_held(&ce->guc_active.lock);

        for (i = 0; i < ARRAY_SIZE(ce->guc_prio_count); ++i) {
                if (ce->guc_prio_count[i]) {
                        guc_context_set_prio(guc, ce, i);
                        break;
                }
        }
}

static inline bool new_guc_prio_higher(u8 old_guc_prio, u8 new_guc_prio)
{
        /* Lower value is higher priority */
        return new_guc_prio < old_guc_prio;
}

static void add_to_context(struct i915_request *rq)
{
        struct intel_context *ce = rq->context;
        u8 new_guc_prio = map_i915_prio_to_guc_prio(rq_prio(rq));

        GEM_BUG_ON(rq->guc_prio == GUC_PRIO_FINI);

        spin_lock(&ce->guc_active.lock);
        list_move_tail(&rq->sched.link, &ce->guc_active.requests);

        if (rq->guc_prio == GUC_PRIO_INIT) {
                rq->guc_prio = new_guc_prio;
                add_context_inflight_prio(ce, rq->guc_prio);
        } else if (new_guc_prio_higher(rq->guc_prio, new_guc_prio)) {
                sub_context_inflight_prio(ce, rq->guc_prio);
                rq->guc_prio = new_guc_prio;
                add_context_inflight_prio(ce, rq->guc_prio);
        }
        update_context_prio(ce);

        spin_unlock(&ce->guc_active.lock);
}

static void guc_prio_fini(struct i915_request *rq, struct intel_context *ce)
{
        lockdep_assert_held(&ce->guc_active.lock);

        if (rq->guc_prio != GUC_PRIO_INIT &&
            rq->guc_prio != GUC_PRIO_FINI) {
                sub_context_inflight_prio(ce, rq->guc_prio);
                update_context_prio(ce);
        }
        rq->guc_prio = GUC_PRIO_FINI;
}

static void remove_from_context(struct i915_request *rq)
{
        struct intel_context *ce = rq->context;

        spin_lock_irq(&ce->guc_active.lock);

        list_del_init(&rq->sched.link);
        clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);

        /* Prevent further __await_execution() registering a cb, then flush */
        set_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags);

        guc_prio_fini(rq, ce);

        spin_unlock_irq(&ce->guc_active.lock);

        atomic_dec(&ce->guc_id_ref);
        i915_request_notify_execute_cb_imm(rq);
}

static const struct intel_context_ops guc_context_ops = {
        .alloc = guc_context_alloc,

        .pre_pin = guc_context_pre_pin,
        .pin = guc_context_pin,
        .unpin = guc_context_unpin,
        .post_unpin = guc_context_post_unpin,

        .ban = guc_context_ban,

        .cancel_request = guc_context_cancel_request,

        .enter = intel_context_enter_engine,
        .exit = intel_context_exit_engine,

        .sched_disable = guc_context_sched_disable,

        .reset = lrc_reset,
        .destroy = guc_context_destroy,

        .create_virtual = guc_create_virtual,
};

static void __guc_signal_context_fence(struct intel_context *ce)
{
        struct i915_request *rq;

        lockdep_assert_held(&ce->guc_state.lock);

        if (!list_empty(&ce->guc_state.fences))
                trace_intel_context_fence_release(ce);

        list_for_each_entry(rq, &ce->guc_state.fences, guc_fence_link)
                i915_sw_fence_complete(&rq->submit);

        INIT_LIST_HEAD(&ce->guc_state.fences);
}

static void guc_signal_context_fence(struct intel_context *ce)
{
        unsigned long flags;

        spin_lock_irqsave(&ce->guc_state.lock, flags);
        clr_context_wait_for_deregister_to_register(ce);
        __guc_signal_context_fence(ce);
        spin_unlock_irqrestore(&ce->guc_state.lock, flags);
}

static bool context_needs_register(struct intel_context *ce, bool new_guc_id)
{
        return (new_guc_id || test_bit(CONTEXT_LRCA_DIRTY, &ce->flags) ||
                !lrc_desc_registered(ce_to_guc(ce), ce->guc_id)) &&
                !submission_disabled(ce_to_guc(ce));
}

static int guc_request_alloc(struct i915_request *rq)
{
        struct intel_context *ce = rq->context;
        struct intel_guc *guc = ce_to_guc(ce);
        unsigned long flags;
        int ret;

        GEM_BUG_ON(!intel_context_is_pinned(rq->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.
         */
        rq->reserved_space += GUC_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.
         */

        /* Unconditionally invalidate GPU caches and TLBs. */
        ret = rq->engine->emit_flush(rq, EMIT_INVALIDATE);
        if (ret)
                return ret;

        rq->reserved_space -= GUC_REQUEST_SIZE;

        /*
         * Call pin_guc_id here rather than in the pinning step as with
         * dma_resv, contexts can be repeatedly pinned / unpinned trashing the
         * guc_ids and creating horrible race conditions. This is especially bad
         * when guc_ids are being stolen due to over subscription. By the time
         * this function is reached, it is guaranteed that the guc_id will be
         * persistent until the generated request is retired. Thus, sealing these
         * race conditions. It is still safe to fail here if guc_ids are
         * exhausted and return -EAGAIN to the user indicating that they can try
         * again in the future.
         *
         * There is no need for a lock here as the timeline mutex ensures at
         * most one context can be executing this code path at once. The
         * guc_id_ref is incremented once for every request in flight and
         * decremented on each retire. When it is zero, a lock around the
         * increment (in pin_guc_id) is needed to seal a race with unpin_guc_id.
         */
        if (atomic_add_unless(&ce->guc_id_ref, 1, 0))
                goto out;

        ret = pin_guc_id(guc, ce);      /* returns 1 if new guc_id assigned */
        if (unlikely(ret < 0))
                return ret;
        if (context_needs_register(ce, !!ret)) {
                ret = guc_lrc_desc_pin(ce, true);
                if (unlikely(ret)) {    /* unwind */
                        if (ret == -EPIPE) {
                                disable_submission(guc);
                                goto out;       /* GPU will be reset */
                        }
                        atomic_dec(&ce->guc_id_ref);
                        unpin_guc_id(guc, ce);
                        return ret;
                }
        }

        clear_bit(CONTEXT_LRCA_DIRTY, &ce->flags);

out:
        /*
         * We block all requests on this context if a G2H is pending for a
         * schedule disable or context deregistration as the GuC will fail a
         * schedule enable or context registration if either G2H is pending
         * respectfully. Once a G2H returns, the fence is released that is
         * blocking these requests (see guc_signal_context_fence).
         *
         * We can safely check the below fields outside of the lock as it isn't
         * possible for these fields to transition from being clear to set but
         * converse is possible, hence the need for the check within the lock.
         */
        if (likely(!context_wait_for_deregister_to_register(ce) &&
                   !context_pending_disable(ce)))
                return 0;

        spin_lock_irqsave(&ce->guc_state.lock, flags);
        if (context_wait_for_deregister_to_register(ce) ||
            context_pending_disable(ce)) {
                i915_sw_fence_await(&rq->submit);

                list_add_tail(&rq->guc_fence_link, &ce->guc_state.fences);
        }
        spin_unlock_irqrestore(&ce->guc_state.lock, flags);

        return 0;
}

static int guc_virtual_context_pre_pin(struct intel_context *ce,
                                       struct i915_gem_ww_ctx *ww,
                                       void **vaddr)
{
        struct intel_engine_cs *engine = guc_virtual_get_sibling(ce->engine, 0);

        return __guc_context_pre_pin(ce, engine, ww, vaddr);
}

static int guc_virtual_context_pin(struct intel_context *ce, void *vaddr)
{
        struct intel_engine_cs *engine = guc_virtual_get_sibling(ce->engine, 0);

        return __guc_context_pin(ce, engine, vaddr);
}

static void guc_virtual_context_enter(struct intel_context *ce)
{
        intel_engine_mask_t tmp, mask = ce->engine->mask;
        struct intel_engine_cs *engine;

        for_each_engine_masked(engine, ce->engine->gt, mask, tmp)
                intel_engine_pm_get(engine);

        intel_timeline_enter(ce->timeline);
}

static void guc_virtual_context_exit(struct intel_context *ce)
{
        intel_engine_mask_t tmp, mask = ce->engine->mask;
        struct intel_engine_cs *engine;

        for_each_engine_masked(engine, ce->engine->gt, mask, tmp)
                intel_engine_pm_put(engine);

        intel_timeline_exit(ce->timeline);
}

static int guc_virtual_context_alloc(struct intel_context *ce)
{
        struct intel_engine_cs *engine = guc_virtual_get_sibling(ce->engine, 0);

        return lrc_alloc(ce, engine);
}

static const struct intel_context_ops virtual_guc_context_ops = {
        .alloc = guc_virtual_context_alloc,

        .pre_pin = guc_virtual_context_pre_pin,
        .pin = guc_virtual_context_pin,
        .unpin = guc_context_unpin,
        .post_unpin = guc_context_post_unpin,

        .ban = guc_context_ban,

        .cancel_request = guc_context_cancel_request,

        .enter = guc_virtual_context_enter,
        .exit = guc_virtual_context_exit,

        .sched_disable = guc_context_sched_disable,

        .destroy = guc_context_destroy,

        .get_sibling = guc_virtual_get_sibling,
};

static bool
guc_irq_enable_breadcrumbs(struct intel_breadcrumbs *b)
{
        struct intel_engine_cs *sibling;
        intel_engine_mask_t tmp, mask = b->engine_mask;
        bool result = false;

        for_each_engine_masked(sibling, b->irq_engine->gt, mask, tmp)
                result |= intel_engine_irq_enable(sibling);

        return result;
}

static void
guc_irq_disable_breadcrumbs(struct intel_breadcrumbs *b)
{
        struct intel_engine_cs *sibling;
        intel_engine_mask_t tmp, mask = b->engine_mask;

        for_each_engine_masked(sibling, b->irq_engine->gt, mask, tmp)
                intel_engine_irq_disable(sibling);
}

static void guc_init_breadcrumbs(struct intel_engine_cs *engine)
{
        int i;

        /*
         * In GuC submission mode we do not know which physical engine a request
         * will be scheduled on, this creates a problem because the breadcrumb
         * interrupt is per physical engine. To work around this we attach
         * requests and direct all breadcrumb interrupts to the first instance
         * of an engine per class. In addition all breadcrumb interrupts are
         * enabled / disabled across an engine class in unison.
         */
        for (i = 0; i < MAX_ENGINE_INSTANCE; ++i) {
                struct intel_engine_cs *sibling =
                        engine->gt->engine_class[engine->class][i];

                if (sibling) {
                        if (engine->breadcrumbs != sibling->breadcrumbs) {
                                intel_breadcrumbs_put(engine->breadcrumbs);
                                engine->breadcrumbs =
                                        intel_breadcrumbs_get(sibling->breadcrumbs);
                        }
                        break;
                }
        }

        if (engine->breadcrumbs) {
                engine->breadcrumbs->engine_mask |= engine->mask;
                engine->breadcrumbs->irq_enable = guc_irq_enable_breadcrumbs;
                engine->breadcrumbs->irq_disable = guc_irq_disable_breadcrumbs;
        }
}

static void guc_bump_inflight_request_prio(struct i915_request *rq,
                                           int prio)
{
        struct intel_context *ce = rq->context;
        u8 new_guc_prio = map_i915_prio_to_guc_prio(prio);

        /* Short circuit function */
        if (prio < I915_PRIORITY_NORMAL ||
            rq->guc_prio == GUC_PRIO_FINI ||
            (rq->guc_prio != GUC_PRIO_INIT &&
             !new_guc_prio_higher(rq->guc_prio, new_guc_prio)))
                return;

        spin_lock(&ce->guc_active.lock);
        if (rq->guc_prio != GUC_PRIO_FINI) {
                if (rq->guc_prio != GUC_PRIO_INIT)
                        sub_context_inflight_prio(ce, rq->guc_prio);
                rq->guc_prio = new_guc_prio;
                add_context_inflight_prio(ce, rq->guc_prio);
                update_context_prio(ce);
        }
        spin_unlock(&ce->guc_active.lock);
}

static void guc_retire_inflight_request_prio(struct i915_request *rq)
{
        struct intel_context *ce = rq->context;

        spin_lock(&ce->guc_active.lock);
        guc_prio_fini(rq, ce);
        spin_unlock(&ce->guc_active.lock);
}

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 guc_sanitize(struct intel_engine_cs *engine)
{
        /*
         * 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);

        /*
         * The kernel_context HWSP is stored in the status_page. As above,
         * that may be lost on resume/initialisation, and so we need to
         * reset the value in the HWSP.
         */
        sanitize_hwsp(engine);

        /* And scrub the dirty cachelines for the HWSP */
        clflush_cache_range(engine->status_page.addr, PAGE_SIZE);
}

static void setup_hwsp(struct intel_engine_cs *engine)
{
        intel_engine_set_hwsp_writemask(engine, ~0u); /* HWSTAM */

        ENGINE_WRITE_FW(engine,
                        RING_HWS_PGA,
                        i915_ggtt_offset(engine->status_page.vma));
}

static void start_engine(struct intel_engine_cs *engine)
{
        ENGINE_WRITE_FW(engine,
                        RING_MODE_GEN7,
                        _MASKED_BIT_ENABLE(GEN11_GFX_DISABLE_LEGACY_MODE));

        ENGINE_WRITE_FW(engine, RING_MI_MODE, _MASKED_BIT_DISABLE(STOP_RING));
        ENGINE_POSTING_READ(engine, RING_MI_MODE);
}

static int guc_resume(struct intel_engine_cs *engine)
{
        assert_forcewakes_active(engine->uncore, FORCEWAKE_ALL);

        intel_mocs_init_engine(engine);

        intel_breadcrumbs_reset(engine->breadcrumbs);

        setup_hwsp(engine);
        start_engine(engine);

        return 0;
}

static bool guc_sched_engine_disabled(struct i915_sched_engine *sched_engine)
{
        return !sched_engine->tasklet.callback;
}

static void guc_set_default_submission(struct intel_engine_cs *engine)
{
        engine->submit_request = guc_submit_request;
}

static inline void guc_kernel_context_pin(struct intel_guc *guc,
                                          struct intel_context *ce)
{
        if (context_guc_id_invalid(ce))
                pin_guc_id(guc, ce);
        guc_lrc_desc_pin(ce, true);
}

static inline void guc_init_lrc_mapping(struct intel_guc *guc)
{
        struct intel_gt *gt = guc_to_gt(guc);
        struct intel_engine_cs *engine;
        enum intel_engine_id id;

        /* make sure all descriptors are clean... */
        xa_destroy(&guc->context_lookup);

        /*
         * Some contexts might have been pinned before we enabled GuC
         * submission, so we need to add them to the GuC bookeeping.
         * Also, after a reset the of the GuC we want to make sure that the
         * information shared with GuC is properly reset. The kernel LRCs are
         * not attached to the gem_context, so they need to be added separately.
         *
         * Note: we purposefully do not check the return of guc_lrc_desc_pin,
         * because that function can only fail if a reset is just starting. This
         * is at the end of reset so presumably another reset isn't happening
         * and even it did this code would be run again.
         */

        for_each_engine(engine, gt, id)
                if (engine->kernel_context)
                        guc_kernel_context_pin(guc, engine->kernel_context);
}

static void guc_release(struct intel_engine_cs *engine)
{
        engine->sanitize = NULL; /* no longer in control, nothing to sanitize */

        intel_engine_cleanup_common(engine);
        lrc_fini_wa_ctx(engine);
}

static void virtual_guc_bump_serial(struct intel_engine_cs *engine)
{
        struct intel_engine_cs *e;
        intel_engine_mask_t tmp, mask = engine->mask;

        for_each_engine_masked(e, engine->gt, mask, tmp)
                e->serial++;
}

static void guc_default_vfuncs(struct intel_engine_cs *engine)
{
        /* Default vfuncs which can be overridden by each engine. */

        engine->resume = guc_resume;

        engine->cops = &guc_context_ops;
        engine->request_alloc = guc_request_alloc;
        engine->add_active_request = add_to_context;
        engine->remove_active_request = remove_from_context;

        engine->sched_engine->schedule = i915_schedule;

        engine->reset.prepare = guc_reset_nop;
        engine->reset.rewind = guc_rewind_nop;
        engine->reset.cancel = guc_reset_nop;
        engine->reset.finish = guc_reset_nop;

        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 = guc_set_default_submission;

        engine->flags |= I915_ENGINE_HAS_PREEMPTION;
        engine->flags |= I915_ENGINE_HAS_TIMESLICES;

        /*
         * TODO: GuC supports timeslicing and semaphores as well, but they're
         * handled by the firmware so some minor tweaks are required before
         * enabling.
         *
         * engine->flags |= I915_ENGINE_HAS_SEMAPHORES;
         */

        engine->emit_bb_start = gen8_emit_bb_start;
}

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;
        }
}

static inline void guc_default_irqs(struct intel_engine_cs *engine)
{
        engine->irq_keep_mask = GT_RENDER_USER_INTERRUPT;
        intel_engine_set_irq_handler(engine, cs_irq_handler);
}

static void guc_sched_engine_destroy(struct kref *kref)
{
        struct i915_sched_engine *sched_engine =
                container_of(kref, typeof(*sched_engine), ref);
        struct intel_guc *guc = sched_engine->private_data;

        guc->sched_engine = NULL;
        tasklet_kill(&sched_engine->tasklet); /* flush the callback */
        kfree(sched_engine);
}

int intel_guc_submission_setup(struct intel_engine_cs *engine)
{
        struct drm_i915_private *i915 = engine->i915;
        struct intel_guc *guc = &engine->gt->uc.guc;

        /*
         * The setup relies on several assumptions (e.g. irqs always enabled)
         * that are only valid on gen11+
         */
        GEM_BUG_ON(GRAPHICS_VER(i915) < 11);

        if (!guc->sched_engine) {
                guc->sched_engine = i915_sched_engine_create(ENGINE_VIRTUAL);
                if (!guc->sched_engine)
                        return -ENOMEM;

                guc->sched_engine->schedule = i915_schedule;
                guc->sched_engine->disabled = guc_sched_engine_disabled;
                guc->sched_engine->private_data = guc;
                guc->sched_engine->destroy = guc_sched_engine_destroy;
                guc->sched_engine->bump_inflight_request_prio =
                        guc_bump_inflight_request_prio;
                guc->sched_engine->retire_inflight_request_prio =
                        guc_retire_inflight_request_prio;
                tasklet_setup(&guc->sched_engine->tasklet,
                              guc_submission_tasklet);
        }
        i915_sched_engine_put(engine->sched_engine);
        engine->sched_engine = i915_sched_engine_get(guc->sched_engine);

        guc_default_vfuncs(engine);
        guc_default_irqs(engine);
        guc_init_breadcrumbs(engine);

        if (engine->class == RENDER_CLASS)
                rcs_submission_override(engine);

        lrc_init_wa_ctx(engine);

        /* Finally, take ownership and responsibility for cleanup! */
        engine->sanitize = guc_sanitize;
        engine->release = guc_release;

        return 0;
}

void intel_guc_submission_enable(struct intel_guc *guc)
{
        guc_init_lrc_mapping(guc);
}

void intel_guc_submission_disable(struct intel_guc *guc)
{
        /* Note: By the time we're here, GuC may have already been reset */
}

static bool __guc_submission_supported(struct intel_guc *guc)
{
        /* GuC submission is unavailable for pre-Gen11 */
        return intel_guc_is_supported(guc) &&
               GRAPHICS_VER(guc_to_gt(guc)->i915) >= 11;
}

static bool __guc_submission_selected(struct intel_guc *guc)
{
        struct drm_i915_private *i915 = guc_to_gt(guc)->i915;

        if (!intel_guc_submission_is_supported(guc))
                return false;

        return i915->params.enable_guc & ENABLE_GUC_SUBMISSION;
}

void intel_guc_submission_init_early(struct intel_guc *guc)
{
        guc->submission_supported = __guc_submission_supported(guc);
        guc->submission_selected = __guc_submission_selected(guc);
}

static inline struct intel_context *
g2h_context_lookup(struct intel_guc *guc, u32 desc_idx)
{
        struct intel_context *ce;

        if (unlikely(desc_idx >= GUC_MAX_LRC_DESCRIPTORS)) {
                drm_err(&guc_to_gt(guc)->i915->drm,
                        "Invalid desc_idx %u", desc_idx);
                return NULL;
        }

        ce = __get_context(guc, desc_idx);
        if (unlikely(!ce)) {
                drm_err(&guc_to_gt(guc)->i915->drm,
                        "Context is NULL, desc_idx %u", desc_idx);
                return NULL;
        }

        return ce;
}

static void decr_outstanding_submission_g2h(struct intel_guc *guc)
{
        if (atomic_dec_and_test(&guc->outstanding_submission_g2h))
                wake_up_all(&guc->ct.wq);
}

int intel_guc_deregister_done_process_msg(struct intel_guc *guc,
                                          const u32 *msg,
                                          u32 len)
{
        struct intel_context *ce;
        u32 desc_idx = msg[0];

        if (unlikely(len < 1)) {
                drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
                return -EPROTO;
        }

        ce = g2h_context_lookup(guc, desc_idx);
        if (unlikely(!ce))
                return -EPROTO;

        trace_intel_context_deregister_done(ce);

        if (context_wait_for_deregister_to_register(ce)) {
                struct intel_runtime_pm *runtime_pm =
                        &ce->engine->gt->i915->runtime_pm;
                intel_wakeref_t wakeref;

                /*
                 * Previous owner of this guc_id has been deregistered, now safe
                 * register this context.
                 */
                with_intel_runtime_pm(runtime_pm, wakeref)
                        register_context(ce, true);
                guc_signal_context_fence(ce);
                intel_context_put(ce);
        } else if (context_destroyed(ce)) {
                /* Context has been destroyed */
                release_guc_id(guc, ce);
                __guc_context_destroy(ce);
        }

        decr_outstanding_submission_g2h(guc);

        return 0;
}

int intel_guc_sched_done_process_msg(struct intel_guc *guc,
                                     const u32 *msg,
                                     u32 len)
{
        struct intel_context *ce;
        unsigned long flags;
        u32 desc_idx = msg[0];

        if (unlikely(len < 2)) {
                drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
                return -EPROTO;
        }

        ce = g2h_context_lookup(guc, desc_idx);
        if (unlikely(!ce))
                return -EPROTO;

        if (unlikely(context_destroyed(ce) ||
                     (!context_pending_enable(ce) &&
                     !context_pending_disable(ce)))) {
                drm_err(&guc_to_gt(guc)->i915->drm,
                        "Bad context sched_state 0x%x, 0x%x, desc_idx %u",
                        atomic_read(&ce->guc_sched_state_no_lock),
                        ce->guc_state.sched_state, desc_idx);
                return -EPROTO;
        }

        trace_intel_context_sched_done(ce);

        if (context_pending_enable(ce)) {
                clr_context_pending_enable(ce);
        } else if (context_pending_disable(ce)) {
                bool banned;

                /*
                 * Unpin must be done before __guc_signal_context_fence,
                 * otherwise a race exists between the requests getting
                 * submitted + retired before this unpin completes resulting in
                 * the pin_count going to zero and the context still being
                 * enabled.
                 */
                intel_context_sched_disable_unpin(ce);

                spin_lock_irqsave(&ce->guc_state.lock, flags);
                banned = context_banned(ce);
                clr_context_banned(ce);
                clr_context_pending_disable(ce);
                __guc_signal_context_fence(ce);
                guc_blocked_fence_complete(ce);
                spin_unlock_irqrestore(&ce->guc_state.lock, flags);

                if (banned) {
                        guc_cancel_context_requests(ce);
                        intel_engine_signal_breadcrumbs(ce->engine);
                }
        }

        decr_outstanding_submission_g2h(guc);
        intel_context_put(ce);

        return 0;
}

static void capture_error_state(struct intel_guc *guc,
                                struct intel_context *ce)
{
        struct intel_gt *gt = guc_to_gt(guc);
        struct drm_i915_private *i915 = gt->i915;
        struct intel_engine_cs *engine = __context_to_physical_engine(ce);
        intel_wakeref_t wakeref;

        intel_engine_set_hung_context(engine, ce);
        with_intel_runtime_pm(&i915->runtime_pm, wakeref)
                i915_capture_error_state(gt, engine->mask);
        atomic_inc(&i915->gpu_error.reset_engine_count[engine->uabi_class]);
}

static void guc_context_replay(struct intel_context *ce)
{
        struct i915_sched_engine *sched_engine = ce->engine->sched_engine;

        __guc_reset_context(ce, true);
        tasklet_hi_schedule(&sched_engine->tasklet);
}

static void guc_handle_context_reset(struct intel_guc *guc,
                                     struct intel_context *ce)
{
        trace_intel_context_reset(ce);

        if (likely(!intel_context_is_banned(ce))) {
                capture_error_state(guc, ce);
                guc_context_replay(ce);
        }
}

int intel_guc_context_reset_process_msg(struct intel_guc *guc,
                                        const u32 *msg, u32 len)
{
        struct intel_context *ce;
        int desc_idx;

        if (unlikely(len != 1)) {
                drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
                return -EPROTO;
        }

        desc_idx = msg[0];
        ce = g2h_context_lookup(guc, desc_idx);
        if (unlikely(!ce))
                return -EPROTO;

        guc_handle_context_reset(guc, ce);

        return 0;
}

static struct intel_engine_cs *
guc_lookup_engine(struct intel_guc *guc, u8 guc_class, u8 instance)
{
        struct intel_gt *gt = guc_to_gt(guc);
        u8 engine_class = guc_class_to_engine_class(guc_class);

        /* Class index is checked in class converter */
        GEM_BUG_ON(instance > MAX_ENGINE_INSTANCE);

        return gt->engine_class[engine_class][instance];
}

int intel_guc_engine_failure_process_msg(struct intel_guc *guc,
                                         const u32 *msg, u32 len)
{
        struct intel_engine_cs *engine;
        u8 guc_class, instance;
        u32 reason;

        if (unlikely(len != 3)) {
                drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
                return -EPROTO;
        }

        guc_class = msg[0];
        instance = msg[1];
        reason = msg[2];

        engine = guc_lookup_engine(guc, guc_class, instance);
        if (unlikely(!engine)) {
                drm_err(&guc_to_gt(guc)->i915->drm,
                        "Invalid engine %d:%d", guc_class, instance);
                return -EPROTO;
        }

        intel_gt_handle_error(guc_to_gt(guc), engine->mask,
                              I915_ERROR_CAPTURE,
                              "GuC failed to reset %s (reason=0x%08x)\n",
                              engine->name, reason);

        return 0;
}

void intel_guc_find_hung_context(struct intel_engine_cs *engine)
{
        struct intel_guc *guc = &engine->gt->uc.guc;
        struct intel_context *ce;
        struct i915_request *rq;
        unsigned long index;

        /* Reset called during driver load? GuC not yet initialised! */
        if (unlikely(!guc_submission_initialized(guc)))
                return;

        xa_for_each(&guc->context_lookup, index, ce) {
                if (!intel_context_is_pinned(ce))
                        continue;

                if (intel_engine_is_virtual(ce->engine)) {
                        if (!(ce->engine->mask & engine->mask))
                                continue;
                } else {
                        if (ce->engine != engine)
                                continue;
                }

                list_for_each_entry(rq, &ce->guc_active.requests, sched.link) {
                        if (i915_test_request_state(rq) != I915_REQUEST_ACTIVE)
                                continue;

                        intel_engine_set_hung_context(engine, ce);

                        /* Can only cope with one hang at a time... */
                        return;
                }
        }
}

void intel_guc_dump_active_requests(struct intel_engine_cs *engine,
                                    struct i915_request *hung_rq,
                                    struct drm_printer *m)
{
        struct intel_guc *guc = &engine->gt->uc.guc;
        struct intel_context *ce;
        unsigned long index;
        unsigned long flags;

        /* Reset called during driver load? GuC not yet initialised! */
        if (unlikely(!guc_submission_initialized(guc)))
                return;

        xa_for_each(&guc->context_lookup, index, ce) {
                if (!intel_context_is_pinned(ce))
                        continue;

                if (intel_engine_is_virtual(ce->engine)) {
                        if (!(ce->engine->mask & engine->mask))
                                continue;
                } else {
                        if (ce->engine != engine)
                                continue;
                }

                spin_lock_irqsave(&ce->guc_active.lock, flags);
                intel_engine_dump_active_requests(&ce->guc_active.requests,
                                                  hung_rq, m);
                spin_unlock_irqrestore(&ce->guc_active.lock, flags);
        }
}

void intel_guc_submission_print_info(struct intel_guc *guc,
                                     struct drm_printer *p)
{
        struct i915_sched_engine *sched_engine = guc->sched_engine;
        struct rb_node *rb;
        unsigned long flags;

        if (!sched_engine)
                return;

        drm_printf(p, "GuC Number Outstanding Submission G2H: %u\n",
                   atomic_read(&guc->outstanding_submission_g2h));
        drm_printf(p, "GuC tasklet count: %u\n\n",
                   atomic_read(&sched_engine->tasklet.count));

        spin_lock_irqsave(&sched_engine->lock, flags);
        drm_printf(p, "Requests in GuC submit tasklet:\n");
        for (rb = rb_first_cached(&sched_engine->queue); rb; rb = rb_next(rb)) {
                struct i915_priolist *pl = to_priolist(rb);
                struct i915_request *rq;

                priolist_for_each_request(rq, pl)
                        drm_printf(p, "guc_id=%u, seqno=%llu\n",
                                   rq->context->guc_id,
                                   rq->fence.seqno);
        }
        spin_unlock_irqrestore(&sched_engine->lock, flags);
        drm_printf(p, "\n");
}

static inline void guc_log_context_priority(struct drm_printer *p,
                                            struct intel_context *ce)
{
        int i;

        drm_printf(p, "\t\tPriority: %d\n",
                   ce->guc_prio);
        drm_printf(p, "\t\tNumber Requests (lower index == higher priority)\n");
        for (i = GUC_CLIENT_PRIORITY_KMD_HIGH;
             i < GUC_CLIENT_PRIORITY_NUM; ++i) {
                drm_printf(p, "\t\tNumber requests in priority band[%d]: %d\n",
                           i, ce->guc_prio_count[i]);
        }
        drm_printf(p, "\n");
}

void intel_guc_submission_print_context_info(struct intel_guc *guc,
                                             struct drm_printer *p)
{
        struct intel_context *ce;
        unsigned long index;

        xa_for_each(&guc->context_lookup, index, ce) {
                drm_printf(p, "GuC lrc descriptor %u:\n", ce->guc_id);
                drm_printf(p, "\tHW Context Desc: 0x%08x\n", ce->lrc.lrca);
                drm_printf(p, "\t\tLRC Head: Internal %u, Memory %u\n",
                           ce->ring->head,
                           ce->lrc_reg_state[CTX_RING_HEAD]);
                drm_printf(p, "\t\tLRC Tail: Internal %u, Memory %u\n",
                           ce->ring->tail,
                           ce->lrc_reg_state[CTX_RING_TAIL]);
                drm_printf(p, "\t\tContext Pin Count: %u\n",
                           atomic_read(&ce->pin_count));
                drm_printf(p, "\t\tGuC ID Ref Count: %u\n",
                           atomic_read(&ce->guc_id_ref));
                drm_printf(p, "\t\tSchedule State: 0x%x, 0x%x\n\n",
                           ce->guc_state.sched_state,
                           atomic_read(&ce->guc_sched_state_no_lock));

                guc_log_context_priority(p, ce);
        }
}

static struct intel_context *
guc_create_virtual(struct intel_engine_cs **siblings, unsigned int count)
{
        struct guc_virtual_engine *ve;
        struct intel_guc *guc;
        unsigned int n;
        int err;

        ve = kzalloc(sizeof(*ve), GFP_KERNEL);
        if (!ve)
                return ERR_PTR(-ENOMEM);

        guc = &siblings[0]->gt->uc.guc;

        ve->base.i915 = siblings[0]->i915;
        ve->base.gt = siblings[0]->gt;
        ve->base.uncore = siblings[0]->uncore;
        ve->base.id = -1;

        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;
        ve->base.saturated = ALL_ENGINES;

        snprintf(ve->base.name, sizeof(ve->base.name), "virtual");

        ve->base.sched_engine = i915_sched_engine_get(guc->sched_engine);

        ve->base.cops = &virtual_guc_context_ops;
        ve->base.request_alloc = guc_request_alloc;
        ve->base.bump_serial = virtual_guc_bump_serial;

        ve->base.submit_request = guc_submit_request;

        ve->base.flags = I915_ENGINE_IS_VIRTUAL;

        intel_context_init(&ve->context, &ve->base);

        for (n = 0; n < count; n++) {
                struct intel_engine_cs *sibling = siblings[n];

                GEM_BUG_ON(!is_power_of_2(sibling->mask));
                if (sibling->mask & ve->base.mask) {
                        DRM_DEBUG("duplicate %s entry in load balancer\n",
                                  sibling->name);
                        err = -EINVAL;
                        goto err_put;
                }

                ve->base.mask |= sibling->mask;

                if (n != 0 && ve->base.class != sibling->class) {
                        DRM_DEBUG("invalid mixing of engine class, sibling %d, already %d\n",
                                  sibling->class, ve->base.class);
                        err = -EINVAL;
                        goto err_put;
                } else if (n == 0) {
                        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;