io_uring: reset -EBUSY error when io sq thread is waken up

[thirdparty/linux.git] / drivers / gpu / drm / i915 / gvt / scheduler.c

/*
 * Copyright(c) 2011-2016 Intel Corporation. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * Authors:
 *    Zhi Wang <zhi.a.wang@intel.com>
 *
 * Contributors:
 *    Ping Gao <ping.a.gao@intel.com>
 *    Tina Zhang <tina.zhang@intel.com>
 *    Chanbin Du <changbin.du@intel.com>
 *    Min He <min.he@intel.com>
 *    Bing Niu <bing.niu@intel.com>
 *    Zhenyu Wang <zhenyuw@linux.intel.com>
 *
 */

#include <linux/kthread.h>

#include "gem/i915_gem_pm.h"
#include "gt/intel_context.h"
#include "gt/intel_ring.h"

#include "i915_drv.h"
#include "i915_gem_gtt.h"
#include "gvt.h"

#define RING_CTX_OFF(x) \
        offsetof(struct execlist_ring_context, x)

static void set_context_pdp_root_pointer(
                struct execlist_ring_context *ring_context,
                u32 pdp[8])
{
        int i;

        for (i = 0; i < 8; i++)
                ring_context->pdps[i].val = pdp[7 - i];
}

static void update_shadow_pdps(struct intel_vgpu_workload *workload)
{
        struct drm_i915_gem_object *ctx_obj =
                workload->req->context->state->obj;
        struct execlist_ring_context *shadow_ring_context;
        struct page *page;

        if (WARN_ON(!workload->shadow_mm))
                return;

        if (WARN_ON(!atomic_read(&workload->shadow_mm->pincount)))
                return;

        page = i915_gem_object_get_page(ctx_obj, LRC_STATE_PN);
        shadow_ring_context = kmap(page);
        set_context_pdp_root_pointer(shadow_ring_context,
                        (void *)workload->shadow_mm->ppgtt_mm.shadow_pdps);
        kunmap(page);
}

/*
 * when populating shadow ctx from guest, we should not overrride oa related
 * registers, so that they will not be overlapped by guest oa configs. Thus
 * made it possible to capture oa data from host for both host and guests.
 */
static void sr_oa_regs(struct intel_vgpu_workload *workload,
                u32 *reg_state, bool save)
{
        struct drm_i915_private *dev_priv = workload->vgpu->gvt->gt->i915;
        u32 ctx_oactxctrl = dev_priv->perf.ctx_oactxctrl_offset;
        u32 ctx_flexeu0 = dev_priv->perf.ctx_flexeu0_offset;
        int i = 0;
        u32 flex_mmio[] = {
                i915_mmio_reg_offset(EU_PERF_CNTL0),
                i915_mmio_reg_offset(EU_PERF_CNTL1),
                i915_mmio_reg_offset(EU_PERF_CNTL2),
                i915_mmio_reg_offset(EU_PERF_CNTL3),
                i915_mmio_reg_offset(EU_PERF_CNTL4),
                i915_mmio_reg_offset(EU_PERF_CNTL5),
                i915_mmio_reg_offset(EU_PERF_CNTL6),
        };

        if (workload->engine->id != RCS0)
                return;

        if (save) {
                workload->oactxctrl = reg_state[ctx_oactxctrl + 1];

                for (i = 0; i < ARRAY_SIZE(workload->flex_mmio); i++) {
                        u32 state_offset = ctx_flexeu0 + i * 2;

                        workload->flex_mmio[i] = reg_state[state_offset + 1];
                }
        } else {
                reg_state[ctx_oactxctrl] =
                        i915_mmio_reg_offset(GEN8_OACTXCONTROL);
                reg_state[ctx_oactxctrl + 1] = workload->oactxctrl;

                for (i = 0; i < ARRAY_SIZE(workload->flex_mmio); i++) {
                        u32 state_offset = ctx_flexeu0 + i * 2;
                        u32 mmio = flex_mmio[i];

                        reg_state[state_offset] = mmio;
                        reg_state[state_offset + 1] = workload->flex_mmio[i];
                }
        }
}

static int populate_shadow_context(struct intel_vgpu_workload *workload)
{
        struct intel_vgpu *vgpu = workload->vgpu;
        struct intel_gvt *gvt = vgpu->gvt;
        struct drm_i915_gem_object *ctx_obj =
                workload->req->context->state->obj;
        struct execlist_ring_context *shadow_ring_context;
        struct page *page;
        void *dst;
        unsigned long context_gpa, context_page_num;
        int i;

        page = i915_gem_object_get_page(ctx_obj, LRC_STATE_PN);
        shadow_ring_context = kmap(page);

        sr_oa_regs(workload, (u32 *)shadow_ring_context, true);
#define COPY_REG(name) \
        intel_gvt_hypervisor_read_gpa(vgpu, workload->ring_context_gpa \
                + RING_CTX_OFF(name.val), &shadow_ring_context->name.val, 4)
#define COPY_REG_MASKED(name) {\
                intel_gvt_hypervisor_read_gpa(vgpu, workload->ring_context_gpa \
                                              + RING_CTX_OFF(name.val),\
                                              &shadow_ring_context->name.val, 4);\
                shadow_ring_context->name.val |= 0xffff << 16;\
        }

        COPY_REG_MASKED(ctx_ctrl);
        COPY_REG(ctx_timestamp);

        if (workload->engine->id == RCS0) {
                COPY_REG(bb_per_ctx_ptr);
                COPY_REG(rcs_indirect_ctx);
                COPY_REG(rcs_indirect_ctx_offset);
        }
#undef COPY_REG
#undef COPY_REG_MASKED

        intel_gvt_hypervisor_read_gpa(vgpu,
                        workload->ring_context_gpa +
                        sizeof(*shadow_ring_context),
                        (void *)shadow_ring_context +
                        sizeof(*shadow_ring_context),
                        I915_GTT_PAGE_SIZE - sizeof(*shadow_ring_context));

        sr_oa_regs(workload, (u32 *)shadow_ring_context, false);
        kunmap(page);

        if (IS_RESTORE_INHIBIT(shadow_ring_context->ctx_ctrl.val))
                return 0;

        gvt_dbg_sched("ring %s workload lrca %x",
                      workload->engine->name,
                      workload->ctx_desc.lrca);

        context_page_num = workload->engine->context_size;
        context_page_num = context_page_num >> PAGE_SHIFT;

        if (IS_BROADWELL(gvt->gt->i915) && workload->engine->id == RCS0)
                context_page_num = 19;

        i = 2;
        while (i < context_page_num) {
                context_gpa = intel_vgpu_gma_to_gpa(vgpu->gtt.ggtt_mm,
                                (u32)((workload->ctx_desc.lrca + i) <<
                                I915_GTT_PAGE_SHIFT));
                if (context_gpa == INTEL_GVT_INVALID_ADDR) {
                        gvt_vgpu_err("Invalid guest context descriptor\n");
                        return -EFAULT;
                }

                page = i915_gem_object_get_page(ctx_obj, i);
                dst = kmap(page);
                intel_gvt_hypervisor_read_gpa(vgpu, context_gpa, dst,
                                I915_GTT_PAGE_SIZE);
                kunmap(page);
                i++;
        }
        return 0;
}

static inline bool is_gvt_request(struct i915_request *rq)
{
        return intel_context_force_single_submission(rq->context);
}

static void save_ring_hw_state(struct intel_vgpu *vgpu,
                               const struct intel_engine_cs *engine)
{
        struct intel_uncore *uncore = engine->uncore;
        i915_reg_t reg;

        reg = RING_INSTDONE(engine->mmio_base);
        vgpu_vreg(vgpu, i915_mmio_reg_offset(reg)) =
                intel_uncore_read(uncore, reg);

        reg = RING_ACTHD(engine->mmio_base);
        vgpu_vreg(vgpu, i915_mmio_reg_offset(reg)) =
                intel_uncore_read(uncore, reg);

        reg = RING_ACTHD_UDW(engine->mmio_base);
        vgpu_vreg(vgpu, i915_mmio_reg_offset(reg)) =
                intel_uncore_read(uncore, reg);
}

static int shadow_context_status_change(struct notifier_block *nb,
                unsigned long action, void *data)
{
        struct i915_request *rq = data;
        struct intel_gvt *gvt = container_of(nb, struct intel_gvt,
                                shadow_ctx_notifier_block[rq->engine->id]);
        struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
        enum intel_engine_id ring_id = rq->engine->id;
        struct intel_vgpu_workload *workload;
        unsigned long flags;

        if (!is_gvt_request(rq)) {
                spin_lock_irqsave(&scheduler->mmio_context_lock, flags);
                if (action == INTEL_CONTEXT_SCHEDULE_IN &&
                    scheduler->engine_owner[ring_id]) {
                        /* Switch ring from vGPU to host. */
                        intel_gvt_switch_mmio(scheduler->engine_owner[ring_id],
                                              NULL, rq->engine);
                        scheduler->engine_owner[ring_id] = NULL;
                }
                spin_unlock_irqrestore(&scheduler->mmio_context_lock, flags);

                return NOTIFY_OK;
        }

        workload = scheduler->current_workload[ring_id];
        if (unlikely(!workload))
                return NOTIFY_OK;

        switch (action) {
        case INTEL_CONTEXT_SCHEDULE_IN:
                spin_lock_irqsave(&scheduler->mmio_context_lock, flags);
                if (workload->vgpu != scheduler->engine_owner[ring_id]) {
                        /* Switch ring from host to vGPU or vGPU to vGPU. */
                        intel_gvt_switch_mmio(scheduler->engine_owner[ring_id],
                                              workload->vgpu, rq->engine);
                        scheduler->engine_owner[ring_id] = workload->vgpu;
                } else
                        gvt_dbg_sched("skip ring %d mmio switch for vgpu%d\n",
                                      ring_id, workload->vgpu->id);
                spin_unlock_irqrestore(&scheduler->mmio_context_lock, flags);
                atomic_set(&workload->shadow_ctx_active, 1);
                break;
        case INTEL_CONTEXT_SCHEDULE_OUT:
                save_ring_hw_state(workload->vgpu, rq->engine);
                atomic_set(&workload->shadow_ctx_active, 0);
                break;
        case INTEL_CONTEXT_SCHEDULE_PREEMPTED:
                save_ring_hw_state(workload->vgpu, rq->engine);
                break;
        default:
                WARN_ON(1);
                return NOTIFY_OK;
        }
        wake_up(&workload->shadow_ctx_status_wq);
        return NOTIFY_OK;
}

static void
shadow_context_descriptor_update(struct intel_context *ce,
                                 struct intel_vgpu_workload *workload)
{
        u64 desc = ce->lrc_desc;

        /*
         * Update bits 0-11 of the context descriptor which includes flags
         * like GEN8_CTX_* cached in desc_template
         */
        desc &= ~(0x3ull << GEN8_CTX_ADDRESSING_MODE_SHIFT);
        desc |= (u64)workload->ctx_desc.addressing_mode <<
                GEN8_CTX_ADDRESSING_MODE_SHIFT;

        ce->lrc_desc = desc;
}

static int copy_workload_to_ring_buffer(struct intel_vgpu_workload *workload)
{
        struct intel_vgpu *vgpu = workload->vgpu;
        struct i915_request *req = workload->req;
        void *shadow_ring_buffer_va;
        u32 *cs;
        int err;

        if (IS_GEN(req->i915, 9) && is_inhibit_context(req->context))
                intel_vgpu_restore_inhibit_context(vgpu, req);

        /*
         * To track whether a request has started on HW, we can emit a
         * breadcrumb at the beginning of the request and check its
         * timeline's HWSP to see if the breadcrumb has advanced past the
         * start of this request. Actually, the request must have the
         * init_breadcrumb if its timeline set has_init_bread_crumb, or the
         * scheduler might get a wrong state of it during reset. Since the
         * requests from gvt always set the has_init_breadcrumb flag, here
         * need to do the emit_init_breadcrumb for all the requests.
         */
        if (req->engine->emit_init_breadcrumb) {
                err = req->engine->emit_init_breadcrumb(req);
                if (err) {
                        gvt_vgpu_err("fail to emit init breadcrumb\n");
                        return err;
                }
        }

        /* allocate shadow ring buffer */
        cs = intel_ring_begin(workload->req, workload->rb_len / sizeof(u32));
        if (IS_ERR(cs)) {
                gvt_vgpu_err("fail to alloc size =%ld shadow  ring buffer\n",
                        workload->rb_len);
                return PTR_ERR(cs);
        }

        shadow_ring_buffer_va = workload->shadow_ring_buffer_va;

        /* get shadow ring buffer va */
        workload->shadow_ring_buffer_va = cs;

        memcpy(cs, shadow_ring_buffer_va,
                        workload->rb_len);

        cs += workload->rb_len / sizeof(u32);
        intel_ring_advance(workload->req, cs);

        return 0;
}

static void release_shadow_wa_ctx(struct intel_shadow_wa_ctx *wa_ctx)
{
        if (!wa_ctx->indirect_ctx.obj)
                return;

        i915_gem_object_unpin_map(wa_ctx->indirect_ctx.obj);
        i915_gem_object_put(wa_ctx->indirect_ctx.obj);

        wa_ctx->indirect_ctx.obj = NULL;
        wa_ctx->indirect_ctx.shadow_va = NULL;
}

static void set_context_ppgtt_from_shadow(struct intel_vgpu_workload *workload,
                                          struct intel_context *ce)
{
        struct intel_vgpu_mm *mm = workload->shadow_mm;
        struct i915_ppgtt *ppgtt = i915_vm_to_ppgtt(ce->vm);
        int i = 0;

        if (mm->ppgtt_mm.root_entry_type == GTT_TYPE_PPGTT_ROOT_L4_ENTRY) {
                px_dma(ppgtt->pd) = mm->ppgtt_mm.shadow_pdps[0];
        } else {
                for (i = 0; i < GVT_RING_CTX_NR_PDPS; i++) {
                        struct i915_page_directory * const pd =
                                i915_pd_entry(ppgtt->pd, i);

                        px_dma(pd) = mm->ppgtt_mm.shadow_pdps[i];
                }
        }
}

static int
intel_gvt_workload_req_alloc(struct intel_vgpu_workload *workload)
{
        struct intel_vgpu *vgpu = workload->vgpu;
        struct intel_vgpu_submission *s = &vgpu->submission;
        struct i915_request *rq;

        if (workload->req)
                return 0;

        rq = i915_request_create(s->shadow[workload->engine->id]);
        if (IS_ERR(rq)) {
                gvt_vgpu_err("fail to allocate gem request\n");
                return PTR_ERR(rq);
        }

        workload->req = i915_request_get(rq);
        return 0;
}

/**
 * intel_gvt_scan_and_shadow_workload - audit the workload by scanning and
 * shadow it as well, include ringbuffer,wa_ctx and ctx.
 * @workload: an abstract entity for each execlist submission.
 *
 * This function is called before the workload submitting to i915, to make
 * sure the content of the workload is valid.
 */
int intel_gvt_scan_and_shadow_workload(struct intel_vgpu_workload *workload)
{
        struct intel_vgpu *vgpu = workload->vgpu;
        struct intel_vgpu_submission *s = &vgpu->submission;
        int ret;

        lockdep_assert_held(&vgpu->vgpu_lock);

        if (workload->shadow)
                return 0;

        if (!test_and_set_bit(workload->engine->id, s->shadow_ctx_desc_updated))
                shadow_context_descriptor_update(s->shadow[workload->engine->id],
                                                 workload);

        ret = intel_gvt_scan_and_shadow_ringbuffer(workload);
        if (ret)
                return ret;

        if (workload->engine->id == RCS0 &&
            workload->wa_ctx.indirect_ctx.size) {
                ret = intel_gvt_scan_and_shadow_wa_ctx(&workload->wa_ctx);
                if (ret)
                        goto err_shadow;
        }

        workload->shadow = true;
        return 0;

err_shadow:
        release_shadow_wa_ctx(&workload->wa_ctx);
        return ret;
}

static void release_shadow_batch_buffer(struct intel_vgpu_workload *workload);

static int prepare_shadow_batch_buffer(struct intel_vgpu_workload *workload)
{
        struct intel_gvt *gvt = workload->vgpu->gvt;
        const int gmadr_bytes = gvt->device_info.gmadr_bytes_in_cmd;
        struct intel_vgpu_shadow_bb *bb;
        int ret;

        list_for_each_entry(bb, &workload->shadow_bb, list) {
                /* For privilge batch buffer and not wa_ctx, the bb_start_cmd_va
                 * is only updated into ring_scan_buffer, not real ring address
                 * allocated in later copy_workload_to_ring_buffer. pls be noted
                 * shadow_ring_buffer_va is now pointed to real ring buffer va
                 * in copy_workload_to_ring_buffer.
                 */

                if (bb->bb_offset)
                        bb->bb_start_cmd_va = workload->shadow_ring_buffer_va
                                + bb->bb_offset;

                if (bb->ppgtt) {
                        /* for non-priv bb, scan&shadow is only for
                         * debugging purpose, so the content of shadow bb
                         * is the same as original bb. Therefore,
                         * here, rather than switch to shadow bb's gma
                         * address, we directly use original batch buffer's
                         * gma address, and send original bb to hardware
                         * directly
                         */
                        if (bb->clflush & CLFLUSH_AFTER) {
                                drm_clflush_virt_range(bb->va,
                                                bb->obj->base.size);
                                bb->clflush &= ~CLFLUSH_AFTER;
                        }
                        i915_gem_object_finish_access(bb->obj);
                        bb->accessing = false;

                } else {
                        bb->vma = i915_gem_object_ggtt_pin(bb->obj,
                                        NULL, 0, 0, 0);
                        if (IS_ERR(bb->vma)) {
                                ret = PTR_ERR(bb->vma);
                                goto err;
                        }

                        /* relocate shadow batch buffer */
                        bb->bb_start_cmd_va[1] = i915_ggtt_offset(bb->vma);
                        if (gmadr_bytes == 8)
                                bb->bb_start_cmd_va[2] = 0;

                        /* No one is going to touch shadow bb from now on. */
                        if (bb->clflush & CLFLUSH_AFTER) {
                                drm_clflush_virt_range(bb->va,
                                                bb->obj->base.size);
                                bb->clflush &= ~CLFLUSH_AFTER;
                        }

                        ret = i915_gem_object_set_to_gtt_domain(bb->obj,
                                                                false);
                        if (ret)
                                goto err;

                        ret = i915_vma_move_to_active(bb->vma,
                                                      workload->req,
                                                      0);
                        if (ret)
                                goto err;

                        i915_gem_object_finish_access(bb->obj);
                        bb->accessing = false;
                }
        }
        return 0;
err:
        release_shadow_batch_buffer(workload);
        return ret;
}

static void update_wa_ctx_2_shadow_ctx(struct intel_shadow_wa_ctx *wa_ctx)
{
        struct intel_vgpu_workload *workload =
                container_of(wa_ctx, struct intel_vgpu_workload, wa_ctx);
        struct i915_request *rq = workload->req;
        struct execlist_ring_context *shadow_ring_context =
                (struct execlist_ring_context *)rq->context->lrc_reg_state;

        shadow_ring_context->bb_per_ctx_ptr.val =
                (shadow_ring_context->bb_per_ctx_ptr.val &
                (~PER_CTX_ADDR_MASK)) | wa_ctx->per_ctx.shadow_gma;
        shadow_ring_context->rcs_indirect_ctx.val =
                (shadow_ring_context->rcs_indirect_ctx.val &
                (~INDIRECT_CTX_ADDR_MASK)) | wa_ctx->indirect_ctx.shadow_gma;
}

static int prepare_shadow_wa_ctx(struct intel_shadow_wa_ctx *wa_ctx)
{
        struct i915_vma *vma;
        unsigned char *per_ctx_va =
                (unsigned char *)wa_ctx->indirect_ctx.shadow_va +
                wa_ctx->indirect_ctx.size;

        if (wa_ctx->indirect_ctx.size == 0)
                return 0;

        vma = i915_gem_object_ggtt_pin(wa_ctx->indirect_ctx.obj, NULL,
                                       0, CACHELINE_BYTES, 0);
        if (IS_ERR(vma))
                return PTR_ERR(vma);

        /* FIXME: we are not tracking our pinned VMA leaving it
         * up to the core to fix up the stray pin_count upon
         * free.
         */

        wa_ctx->indirect_ctx.shadow_gma = i915_ggtt_offset(vma);

        wa_ctx->per_ctx.shadow_gma = *((unsigned int *)per_ctx_va + 1);
        memset(per_ctx_va, 0, CACHELINE_BYTES);

        update_wa_ctx_2_shadow_ctx(wa_ctx);
        return 0;
}

static void update_vreg_in_ctx(struct intel_vgpu_workload *workload)
{
        vgpu_vreg_t(workload->vgpu, RING_START(workload->engine->mmio_base)) =
                workload->rb_start;
}

static void release_shadow_batch_buffer(struct intel_vgpu_workload *workload)
{
        struct intel_vgpu_shadow_bb *bb, *pos;

        if (list_empty(&workload->shadow_bb))
                return;

        bb = list_first_entry(&workload->shadow_bb,
                        struct intel_vgpu_shadow_bb, list);

        list_for_each_entry_safe(bb, pos, &workload->shadow_bb, list) {
                if (bb->obj) {
                        if (bb->accessing)
                                i915_gem_object_finish_access(bb->obj);

                        if (bb->va && !IS_ERR(bb->va))
                                i915_gem_object_unpin_map(bb->obj);

                        if (bb->vma && !IS_ERR(bb->vma)) {
                                i915_vma_unpin(bb->vma);
                                i915_vma_close(bb->vma);
                        }
                        i915_gem_object_put(bb->obj);
                }
                list_del(&bb->list);
                kfree(bb);
        }
}

static int prepare_workload(struct intel_vgpu_workload *workload)
{
        struct intel_vgpu *vgpu = workload->vgpu;
        struct intel_vgpu_submission *s = &vgpu->submission;
        int ret = 0;

        ret = intel_vgpu_pin_mm(workload->shadow_mm);
        if (ret) {
                gvt_vgpu_err("fail to vgpu pin mm\n");
                return ret;
        }

        if (workload->shadow_mm->type != INTEL_GVT_MM_PPGTT ||
            !workload->shadow_mm->ppgtt_mm.shadowed) {
                gvt_vgpu_err("workload shadow ppgtt isn't ready\n");
                return -EINVAL;
        }

        update_shadow_pdps(workload);

        set_context_ppgtt_from_shadow(workload, s->shadow[workload->engine->id]);

        ret = intel_vgpu_sync_oos_pages(workload->vgpu);
        if (ret) {
                gvt_vgpu_err("fail to vgpu sync oos pages\n");
                goto err_unpin_mm;
        }

        ret = intel_vgpu_flush_post_shadow(workload->vgpu);
        if (ret) {
                gvt_vgpu_err("fail to flush post shadow\n");
                goto err_unpin_mm;
        }

        ret = copy_workload_to_ring_buffer(workload);
        if (ret) {
                gvt_vgpu_err("fail to generate request\n");
                goto err_unpin_mm;
        }

        ret = prepare_shadow_batch_buffer(workload);
        if (ret) {
                gvt_vgpu_err("fail to prepare_shadow_batch_buffer\n");
                goto err_unpin_mm;
        }

        ret = prepare_shadow_wa_ctx(&workload->wa_ctx);
        if (ret) {
                gvt_vgpu_err("fail to prepare_shadow_wa_ctx\n");
                goto err_shadow_batch;
        }

        if (workload->prepare) {
                ret = workload->prepare(workload);
                if (ret)
                        goto err_shadow_wa_ctx;
        }

        return 0;
err_shadow_wa_ctx:
        release_shadow_wa_ctx(&workload->wa_ctx);
err_shadow_batch:
        release_shadow_batch_buffer(workload);
err_unpin_mm:
        intel_vgpu_unpin_mm(workload->shadow_mm);
        return ret;
}

static int dispatch_workload(struct intel_vgpu_workload *workload)
{
        struct intel_vgpu *vgpu = workload->vgpu;
        struct i915_request *rq;
        int ret;

        gvt_dbg_sched("ring id %s prepare to dispatch workload %p\n",
                      workload->engine->name, workload);

        mutex_lock(&vgpu->vgpu_lock);

        ret = intel_gvt_workload_req_alloc(workload);
        if (ret)
                goto err_req;

        ret = intel_gvt_scan_and_shadow_workload(workload);
        if (ret)
                goto out;

        ret = populate_shadow_context(workload);
        if (ret) {
                release_shadow_wa_ctx(&workload->wa_ctx);
                goto out;
        }

        ret = prepare_workload(workload);
out:
        if (ret) {
                /* We might still need to add request with
                 * clean ctx to retire it properly..
                 */
                rq = fetch_and_zero(&workload->req);
                i915_request_put(rq);
        }

        if (!IS_ERR_OR_NULL(workload->req)) {
                gvt_dbg_sched("ring id %s submit workload to i915 %p\n",
                              workload->engine->name, workload->req);
                i915_request_add(workload->req);
                workload->dispatched = true;
        }
err_req:
        if (ret)
                workload->status = ret;
        mutex_unlock(&vgpu->vgpu_lock);
        return ret;
}

static struct intel_vgpu_workload *
pick_next_workload(struct intel_gvt *gvt, struct intel_engine_cs *engine)
{
        struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
        struct intel_vgpu_workload *workload = NULL;

        mutex_lock(&gvt->sched_lock);

        /*
         * no current vgpu / will be scheduled out / no workload
         * bail out
         */
        if (!scheduler->current_vgpu) {
                gvt_dbg_sched("ring %s stop - no current vgpu\n", engine->name);
                goto out;
        }

        if (scheduler->need_reschedule) {
                gvt_dbg_sched("ring %s stop - will reschedule\n", engine->name);
                goto out;
        }

        if (!scheduler->current_vgpu->active ||
            list_empty(workload_q_head(scheduler->current_vgpu, engine)))
                goto out;

        /*
         * still have current workload, maybe the workload disptacher
         * fail to submit it for some reason, resubmit it.
         */
        if (scheduler->current_workload[engine->id]) {
                workload = scheduler->current_workload[engine->id];
                gvt_dbg_sched("ring %s still have current workload %p\n",
                              engine->name, workload);
                goto out;
        }

        /*
         * pick a workload as current workload
         * once current workload is set, schedule policy routines
         * will wait the current workload is finished when trying to
         * schedule out a vgpu.
         */
        scheduler->current_workload[engine->id] =
                list_first_entry(workload_q_head(scheduler->current_vgpu,
                                                 engine),
                                 struct intel_vgpu_workload, list);

        workload = scheduler->current_workload[engine->id];

        gvt_dbg_sched("ring %s pick new workload %p\n", engine->name, workload);

        atomic_inc(&workload->vgpu->submission.running_workload_num);
out:
        mutex_unlock(&gvt->sched_lock);
        return workload;
}

static void update_guest_context(struct intel_vgpu_workload *workload)
{
        struct i915_request *rq = workload->req;
        struct intel_vgpu *vgpu = workload->vgpu;
        struct drm_i915_gem_object *ctx_obj = rq->context->state->obj;
        struct execlist_ring_context *shadow_ring_context;
        struct page *page;
        void *src;
        unsigned long context_gpa, context_page_num;
        int i;
        u32 ring_base;
        u32 head, tail;
        u16 wrap_count;

        gvt_dbg_sched("ring id %d workload lrca %x\n", rq->engine->id,
                      workload->ctx_desc.lrca);

        head = workload->rb_head;
        tail = workload->rb_tail;
        wrap_count = workload->guest_rb_head >> RB_HEAD_WRAP_CNT_OFF;

        if (tail < head) {
                if (wrap_count == RB_HEAD_WRAP_CNT_MAX)
                        wrap_count = 0;
                else
                        wrap_count += 1;
        }

        head = (wrap_count << RB_HEAD_WRAP_CNT_OFF) | tail;

        ring_base = rq->engine->mmio_base;
        vgpu_vreg_t(vgpu, RING_TAIL(ring_base)) = tail;
        vgpu_vreg_t(vgpu, RING_HEAD(ring_base)) = head;

        context_page_num = rq->engine->context_size;
        context_page_num = context_page_num >> PAGE_SHIFT;

        if (IS_BROADWELL(rq->i915) && rq->engine->id == RCS0)
                context_page_num = 19;

        i = 2;

        while (i < context_page_num) {
                context_gpa = intel_vgpu_gma_to_gpa(vgpu->gtt.ggtt_mm,
                                (u32)((workload->ctx_desc.lrca + i) <<
                                        I915_GTT_PAGE_SHIFT));
                if (context_gpa == INTEL_GVT_INVALID_ADDR) {
                        gvt_vgpu_err("invalid guest context descriptor\n");
                        return;
                }

                page = i915_gem_object_get_page(ctx_obj, i);
                src = kmap(page);
                intel_gvt_hypervisor_write_gpa(vgpu, context_gpa, src,
                                I915_GTT_PAGE_SIZE);
                kunmap(page);
                i++;
        }

        intel_gvt_hypervisor_write_gpa(vgpu, workload->ring_context_gpa +
                RING_CTX_OFF(ring_header.val), &workload->rb_tail, 4);

        page = i915_gem_object_get_page(ctx_obj, LRC_STATE_PN);
        shadow_ring_context = kmap(page);

#define COPY_REG(name) \
        intel_gvt_hypervisor_write_gpa(vgpu, workload->ring_context_gpa + \
                RING_CTX_OFF(name.val), &shadow_ring_context->name.val, 4)

        COPY_REG(ctx_ctrl);
        COPY_REG(ctx_timestamp);

#undef COPY_REG

        intel_gvt_hypervisor_write_gpa(vgpu,
                        workload->ring_context_gpa +
                        sizeof(*shadow_ring_context),
                        (void *)shadow_ring_context +
                        sizeof(*shadow_ring_context),
                        I915_GTT_PAGE_SIZE - sizeof(*shadow_ring_context));

        kunmap(page);
}

void intel_vgpu_clean_workloads(struct intel_vgpu *vgpu,
                                intel_engine_mask_t engine_mask)
{
        struct intel_vgpu_submission *s = &vgpu->submission;
        struct drm_i915_private *dev_priv = vgpu->gvt->gt->i915;
        struct intel_engine_cs *engine;
        struct intel_vgpu_workload *pos, *n;
        intel_engine_mask_t tmp;

        /* free the unsubmited workloads in the queues. */
        for_each_engine_masked(engine, &dev_priv->gt, engine_mask, tmp) {
                list_for_each_entry_safe(pos, n,
                        &s->workload_q_head[engine->id], list) {
                        list_del_init(&pos->list);
                        intel_vgpu_destroy_workload(pos);
                }
                clear_bit(engine->id, s->shadow_ctx_desc_updated);
        }
}

static void complete_current_workload(struct intel_gvt *gvt, int ring_id)
{
        struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
        struct intel_vgpu_workload *workload =
                scheduler->current_workload[ring_id];
        struct intel_vgpu *vgpu = workload->vgpu;
        struct intel_vgpu_submission *s = &vgpu->submission;
        struct i915_request *rq = workload->req;
        int event;

        mutex_lock(&vgpu->vgpu_lock);
        mutex_lock(&gvt->sched_lock);

        /* For the workload w/ request, needs to wait for the context
         * switch to make sure request is completed.
         * For the workload w/o request, directly complete the workload.
         */
        if (rq) {
                wait_event(workload->shadow_ctx_status_wq,
                           !atomic_read(&workload->shadow_ctx_active));

                /* If this request caused GPU hang, req->fence.error will
                 * be set to -EIO. Use -EIO to set workload status so
                 * that when this request caused GPU hang, didn't trigger
                 * context switch interrupt to guest.
                 */
                if (likely(workload->status == -EINPROGRESS)) {
                        if (workload->req->fence.error == -EIO)
                                workload->status = -EIO;
                        else
                                workload->status = 0;
                }

                if (!workload->status &&
                    !(vgpu->resetting_eng & BIT(ring_id))) {
                        update_guest_context(workload);

                        for_each_set_bit(event, workload->pending_events,
                                         INTEL_GVT_EVENT_MAX)
                                intel_vgpu_trigger_virtual_event(vgpu, event);
                }

                i915_request_put(fetch_and_zero(&workload->req));
        }

        gvt_dbg_sched("ring id %d complete workload %p status %d\n",
                        ring_id, workload, workload->status);

        scheduler->current_workload[ring_id] = NULL;

        list_del_init(&workload->list);

        if (workload->status || vgpu->resetting_eng & BIT(ring_id)) {
                /* if workload->status is not successful means HW GPU
                 * has occurred GPU hang or something wrong with i915/GVT,
                 * and GVT won't inject context switch interrupt to guest.
                 * So this error is a vGPU hang actually to the guest.
                 * According to this we should emunlate a vGPU hang. If
                 * there are pending workloads which are already submitted
                 * from guest, we should clean them up like HW GPU does.
                 *
                 * if it is in middle of engine resetting, the pending
                 * workloads won't be submitted to HW GPU and will be
                 * cleaned up during the resetting process later, so doing
                 * the workload clean up here doesn't have any impact.
                 **/
                intel_vgpu_clean_workloads(vgpu, BIT(ring_id));
        }

        workload->complete(workload);

        atomic_dec(&s->running_workload_num);
        wake_up(&scheduler->workload_complete_wq);

        if (gvt->scheduler.need_reschedule)
                intel_gvt_request_service(gvt, INTEL_GVT_REQUEST_EVENT_SCHED);

        mutex_unlock(&gvt->sched_lock);
        mutex_unlock(&vgpu->vgpu_lock);
}

static int workload_thread(void *arg)
{
        struct intel_engine_cs *engine = arg;
        const bool need_force_wake = INTEL_GEN(engine->i915) >= 9;
        struct intel_gvt *gvt = engine->i915->gvt;
        struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
        struct intel_vgpu_workload *workload = NULL;
        struct intel_vgpu *vgpu = NULL;
        int ret;
        DEFINE_WAIT_FUNC(wait, woken_wake_function);

        gvt_dbg_core("workload thread for ring %s started\n", engine->name);

        while (!kthread_should_stop()) {
                intel_wakeref_t wakeref;

                add_wait_queue(&scheduler->waitq[engine->id], &wait);
                do {
                        workload = pick_next_workload(gvt, engine);
                        if (workload)
                                break;
                        wait_woken(&wait, TASK_INTERRUPTIBLE,
                                   MAX_SCHEDULE_TIMEOUT);
                } while (!kthread_should_stop());
                remove_wait_queue(&scheduler->waitq[engine->id], &wait);

                if (!workload)
                        break;

                gvt_dbg_sched("ring %s next workload %p vgpu %d\n",
                              engine->name, workload,
                              workload->vgpu->id);

                wakeref = intel_runtime_pm_get(engine->uncore->rpm);

                gvt_dbg_sched("ring %s will dispatch workload %p\n",
                              engine->name, workload);

                if (need_force_wake)
                        intel_uncore_forcewake_get(engine->uncore,
                                                   FORCEWAKE_ALL);
                /*
                 * Update the vReg of the vGPU which submitted this
                 * workload. The vGPU may use these registers for checking
                 * the context state. The value comes from GPU commands
                 * in this workload.
                 */
                update_vreg_in_ctx(workload);

                ret = dispatch_workload(workload);

                if (ret) {
                        vgpu = workload->vgpu;
                        gvt_vgpu_err("fail to dispatch workload, skip\n");
                        goto complete;
                }

                gvt_dbg_sched("ring %s wait workload %p\n",
                              engine->name, workload);
                i915_request_wait(workload->req, 0, MAX_SCHEDULE_TIMEOUT);

complete:
                gvt_dbg_sched("will complete workload %p, status: %d\n",
                              workload, workload->status);

                complete_current_workload(gvt, engine->id);

                if (need_force_wake)
                        intel_uncore_forcewake_put(engine->uncore,
                                                   FORCEWAKE_ALL);

                intel_runtime_pm_put(engine->uncore->rpm, wakeref);
                if (ret && (vgpu_is_vm_unhealthy(ret)))
                        enter_failsafe_mode(vgpu, GVT_FAILSAFE_GUEST_ERR);
        }
        return 0;
}

void intel_gvt_wait_vgpu_idle(struct intel_vgpu *vgpu)
{
        struct intel_vgpu_submission *s = &vgpu->submission;
        struct intel_gvt *gvt = vgpu->gvt;
        struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;

        if (atomic_read(&s->running_workload_num)) {
                gvt_dbg_sched("wait vgpu idle\n");

                wait_event(scheduler->workload_complete_wq,
                                !atomic_read(&s->running_workload_num));
        }
}

void intel_gvt_clean_workload_scheduler(struct intel_gvt *gvt)
{
        struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
        struct intel_engine_cs *engine;
        enum intel_engine_id i;

        gvt_dbg_core("clean workload scheduler\n");

        for_each_engine(engine, gvt->gt, i) {
                atomic_notifier_chain_unregister(
                                        &engine->context_status_notifier,
                                        &gvt->shadow_ctx_notifier_block[i]);
                kthread_stop(scheduler->thread[i]);
        }
}

int intel_gvt_init_workload_scheduler(struct intel_gvt *gvt)
{
        struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
        struct intel_engine_cs *engine;
        enum intel_engine_id i;
        int ret;

        gvt_dbg_core("init workload scheduler\n");

        init_waitqueue_head(&scheduler->workload_complete_wq);

        for_each_engine(engine, gvt->gt, i) {
                init_waitqueue_head(&scheduler->waitq[i]);

                scheduler->thread[i] = kthread_run(workload_thread, engine,
                                                   "gvt:%s", engine->name);
                if (IS_ERR(scheduler->thread[i])) {
                        gvt_err("fail to create workload thread\n");
                        ret = PTR_ERR(scheduler->thread[i]);
                        goto err;
                }

                gvt->shadow_ctx_notifier_block[i].notifier_call =
                                        shadow_context_status_change;
                atomic_notifier_chain_register(&engine->context_status_notifier,
                                        &gvt->shadow_ctx_notifier_block[i]);
        }

        return 0;

err:
        intel_gvt_clean_workload_scheduler(gvt);
        return ret;
}

static void
i915_context_ppgtt_root_restore(struct intel_vgpu_submission *s,
                                struct i915_ppgtt *ppgtt)
{
        int i;

        if (i915_vm_is_4lvl(&ppgtt->vm)) {
                px_dma(ppgtt->pd) = s->i915_context_pml4;
        } else {
                for (i = 0; i < GEN8_3LVL_PDPES; i++) {
                        struct i915_page_directory * const pd =
                                i915_pd_entry(ppgtt->pd, i);

                        px_dma(pd) = s->i915_context_pdps[i];
                }
        }
}

/**
 * intel_vgpu_clean_submission - free submission-related resource for vGPU
 * @vgpu: a vGPU
 *
 * This function is called when a vGPU is being destroyed.
 *
 */
void intel_vgpu_clean_submission(struct intel_vgpu *vgpu)
{
        struct intel_vgpu_submission *s = &vgpu->submission;
        struct intel_engine_cs *engine;
        enum intel_engine_id id;

        intel_vgpu_select_submission_ops(vgpu, ALL_ENGINES, 0);

        i915_context_ppgtt_root_restore(s, i915_vm_to_ppgtt(s->shadow[0]->vm));
        for_each_engine(engine, vgpu->gvt->gt, id)
                intel_context_unpin(s->shadow[id]);

        kmem_cache_destroy(s->workloads);
}


/**
 * intel_vgpu_reset_submission - reset submission-related resource for vGPU
 * @vgpu: a vGPU
 * @engine_mask: engines expected to be reset
 *
 * This function is called when a vGPU is being destroyed.
 *
 */
void intel_vgpu_reset_submission(struct intel_vgpu *vgpu,
                                 intel_engine_mask_t engine_mask)
{
        struct intel_vgpu_submission *s = &vgpu->submission;

        if (!s->active)
                return;

        intel_vgpu_clean_workloads(vgpu, engine_mask);
        s->ops->reset(vgpu, engine_mask);
}

static void
i915_context_ppgtt_root_save(struct intel_vgpu_submission *s,
                             struct i915_ppgtt *ppgtt)
{
        int i;

        if (i915_vm_is_4lvl(&ppgtt->vm)) {
                s->i915_context_pml4 = px_dma(ppgtt->pd);
        } else {
                for (i = 0; i < GEN8_3LVL_PDPES; i++) {
                        struct i915_page_directory * const pd =
                                i915_pd_entry(ppgtt->pd, i);

                        s->i915_context_pdps[i] = px_dma(pd);
                }
        }
}

/**
 * intel_vgpu_setup_submission - setup submission-related resource for vGPU
 * @vgpu: a vGPU
 *
 * This function is called when a vGPU is being created.
 *
 * Returns:
 * Zero on success, negative error code if failed.
 *
 */
int intel_vgpu_setup_submission(struct intel_vgpu *vgpu)
{
        struct drm_i915_private *i915 = vgpu->gvt->gt->i915;
        struct intel_vgpu_submission *s = &vgpu->submission;
        struct intel_engine_cs *engine;
        struct i915_ppgtt *ppgtt;
        enum intel_engine_id i;
        int ret;

        ppgtt = i915_ppgtt_create(&i915->gt);
        if (IS_ERR(ppgtt))
                return PTR_ERR(ppgtt);

        i915_context_ppgtt_root_save(s, ppgtt);

        for_each_engine(engine, vgpu->gvt->gt, i) {
                struct intel_context *ce;

                INIT_LIST_HEAD(&s->workload_q_head[i]);
                s->shadow[i] = ERR_PTR(-EINVAL);

                ce = intel_context_create(engine);
                if (IS_ERR(ce)) {
                        ret = PTR_ERR(ce);
                        goto out_shadow_ctx;
                }

                i915_vm_put(ce->vm);
                ce->vm = i915_vm_get(&ppgtt->vm);
                intel_context_set_single_submission(ce);

                /* Max ring buffer size */
                if (!intel_uc_wants_guc_submission(&engine->gt->uc)) {
                        const unsigned int ring_size = 512 * SZ_4K;

                        ce->ring = __intel_context_ring_size(ring_size);
                }

                ret = intel_context_pin(ce);
                intel_context_put(ce);
                if (ret)
                        goto out_shadow_ctx;

                s->shadow[i] = ce;
        }

        bitmap_zero(s->shadow_ctx_desc_updated, I915_NUM_ENGINES);

        s->workloads = kmem_cache_create_usercopy("gvt-g_vgpu_workload",
                                                  sizeof(struct intel_vgpu_workload), 0,
                                                  SLAB_HWCACHE_ALIGN,
                                                  offsetof(struct intel_vgpu_workload, rb_tail),
                                                  sizeof_field(struct intel_vgpu_workload, rb_tail),
                                                  NULL);

        if (!s->workloads) {
                ret = -ENOMEM;
                goto out_shadow_ctx;
        }

        atomic_set(&s->running_workload_num, 0);
        bitmap_zero(s->tlb_handle_pending, I915_NUM_ENGINES);

        i915_vm_put(&ppgtt->vm);
        return 0;

out_shadow_ctx:
        i915_context_ppgtt_root_restore(s, ppgtt);
        for_each_engine(engine, vgpu->gvt->gt, i) {
                if (IS_ERR(s->shadow[i]))
                        break;

                intel_context_unpin(s->shadow[i]);
                intel_context_put(s->shadow[i]);
        }
        i915_vm_put(&ppgtt->vm);
        return ret;
}

/**
 * intel_vgpu_select_submission_ops - select virtual submission interface
 * @vgpu: a vGPU
 * @engine_mask: either ALL_ENGINES or target engine mask
 * @interface: expected vGPU virtual submission interface
 *
 * This function is called when guest configures submission interface.
 *
 * Returns:
 * Zero on success, negative error code if failed.
 *
 */
int intel_vgpu_select_submission_ops(struct intel_vgpu *vgpu,
                                     intel_engine_mask_t engine_mask,
                                     unsigned int interface)
{
        struct drm_i915_private *i915 = vgpu->gvt->gt->i915;
        struct intel_vgpu_submission *s = &vgpu->submission;
        const struct intel_vgpu_submission_ops *ops[] = {
                [INTEL_VGPU_EXECLIST_SUBMISSION] =
                        &intel_vgpu_execlist_submission_ops,
        };
        int ret;

        if (drm_WARN_ON(&i915->drm, interface >= ARRAY_SIZE(ops)))
                return -EINVAL;

        if (drm_WARN_ON(&i915->drm,
                        interface == 0 && engine_mask != ALL_ENGINES))
                return -EINVAL;

        if (s->active)
                s->ops->clean(vgpu, engine_mask);

        if (interface == 0) {
                s->ops = NULL;
                s->virtual_submission_interface = 0;
                s->active = false;
                gvt_dbg_core("vgpu%d: remove submission ops\n", vgpu->id);
                return 0;
        }

        ret = ops[interface]->init(vgpu, engine_mask);
        if (ret)
                return ret;

        s->ops = ops[interface];
        s->virtual_submission_interface = interface;
        s->active = true;

        gvt_dbg_core("vgpu%d: activate ops [ %s ]\n",
                        vgpu->id, s->ops->name);

        return 0;
}

/**
 * intel_vgpu_destroy_workload - destroy a vGPU workload
 * @workload: workload to destroy
 *
 * This function is called when destroy a vGPU workload.
 *
 */
void intel_vgpu_destroy_workload(struct intel_vgpu_workload *workload)
{
        struct intel_vgpu_submission *s = &workload->vgpu->submission;

        release_shadow_batch_buffer(workload);
        release_shadow_wa_ctx(&workload->wa_ctx);

        if (workload->shadow_mm)
                intel_vgpu_mm_put(workload->shadow_mm);

        kmem_cache_free(s->workloads, workload);
}

static struct intel_vgpu_workload *
alloc_workload(struct intel_vgpu *vgpu)
{
        struct intel_vgpu_submission *s = &vgpu->submission;
        struct intel_vgpu_workload *workload;

        workload = kmem_cache_zalloc(s->workloads, GFP_KERNEL);
        if (!workload)
                return ERR_PTR(-ENOMEM);

        INIT_LIST_HEAD(&workload->list);
        INIT_LIST_HEAD(&workload->shadow_bb);

        init_waitqueue_head(&workload->shadow_ctx_status_wq);
        atomic_set(&workload->shadow_ctx_active, 0);

        workload->status = -EINPROGRESS;
        workload->vgpu = vgpu;

        return workload;
}

#define RING_CTX_OFF(x) \
        offsetof(struct execlist_ring_context, x)

static void read_guest_pdps(struct intel_vgpu *vgpu,
                u64 ring_context_gpa, u32 pdp[8])
{
        u64 gpa;
        int i;

        gpa = ring_context_gpa + RING_CTX_OFF(pdps[0].val);

        for (i = 0; i < 8; i++)
                intel_gvt_hypervisor_read_gpa(vgpu,
                                gpa + i * 8, &pdp[7 - i], 4);
}

static int prepare_mm(struct intel_vgpu_workload *workload)
{
        struct execlist_ctx_descriptor_format *desc = &workload->ctx_desc;
        struct intel_vgpu_mm *mm;
        struct intel_vgpu *vgpu = workload->vgpu;
        enum intel_gvt_gtt_type root_entry_type;
        u64 pdps[GVT_RING_CTX_NR_PDPS];

        switch (desc->addressing_mode) {
        case 1: /* legacy 32-bit */
                root_entry_type = GTT_TYPE_PPGTT_ROOT_L3_ENTRY;
                break;
        case 3: /* legacy 64-bit */
                root_entry_type = GTT_TYPE_PPGTT_ROOT_L4_ENTRY;
                break;
        default:
                gvt_vgpu_err("Advanced Context mode(SVM) is not supported!\n");
                return -EINVAL;
        }

        read_guest_pdps(workload->vgpu, workload->ring_context_gpa, (void *)pdps);

        mm = intel_vgpu_get_ppgtt_mm(workload->vgpu, root_entry_type, pdps);
        if (IS_ERR(mm))
                return PTR_ERR(mm);

        workload->shadow_mm = mm;
        return 0;
}

#define same_context(a, b) (((a)->context_id == (b)->context_id) && \
                ((a)->lrca == (b)->lrca))

/**
 * intel_vgpu_create_workload - create a vGPU workload
 * @vgpu: a vGPU
 * @engine: the engine
 * @desc: a guest context descriptor
 *
 * This function is called when creating a vGPU workload.
 *
 * Returns:
 * struct intel_vgpu_workload * on success, negative error code in
 * pointer if failed.
 *
 */
struct intel_vgpu_workload *
intel_vgpu_create_workload(struct intel_vgpu *vgpu,
                           const struct intel_engine_cs *engine,
                           struct execlist_ctx_descriptor_format *desc)
{
        struct intel_vgpu_submission *s = &vgpu->submission;
        struct list_head *q = workload_q_head(vgpu, engine);
        struct intel_vgpu_workload *last_workload = NULL;
        struct intel_vgpu_workload *workload = NULL;
        u64 ring_context_gpa;
        u32 head, tail, start, ctl, ctx_ctl, per_ctx, indirect_ctx;
        u32 guest_head;
        int ret;

        ring_context_gpa = intel_vgpu_gma_to_gpa(vgpu->gtt.ggtt_mm,
                        (u32)((desc->lrca + 1) << I915_GTT_PAGE_SHIFT));
        if (ring_context_gpa == INTEL_GVT_INVALID_ADDR) {
                gvt_vgpu_err("invalid guest context LRCA: %x\n", desc->lrca);
                return ERR_PTR(-EINVAL);
        }

        intel_gvt_hypervisor_read_gpa(vgpu, ring_context_gpa +
                        RING_CTX_OFF(ring_header.val), &head, 4);

        intel_gvt_hypervisor_read_gpa(vgpu, ring_context_gpa +
                        RING_CTX_OFF(ring_tail.val), &tail, 4);

        guest_head = head;

        head &= RB_HEAD_OFF_MASK;
        tail &= RB_TAIL_OFF_MASK;

        list_for_each_entry_reverse(last_workload, q, list) {

                if (same_context(&last_workload->ctx_desc, desc)) {
                        gvt_dbg_el("ring %s cur workload == last\n",
                                   engine->name);
                        gvt_dbg_el("ctx head %x real head %lx\n", head,
                                   last_workload->rb_tail);
                        /*
                         * cannot use guest context head pointer here,
                         * as it might not be updated at this time
                         */
                        head = last_workload->rb_tail;
                        break;
                }
        }

        gvt_dbg_el("ring %s begin a new workload\n", engine->name);

        /* record some ring buffer register values for scan and shadow */
        intel_gvt_hypervisor_read_gpa(vgpu, ring_context_gpa +
                        RING_CTX_OFF(rb_start.val), &start, 4);
        intel_gvt_hypervisor_read_gpa(vgpu, ring_context_gpa +
                        RING_CTX_OFF(rb_ctrl.val), &ctl, 4);
        intel_gvt_hypervisor_read_gpa(vgpu, ring_context_gpa +
                        RING_CTX_OFF(ctx_ctrl.val), &ctx_ctl, 4);

        if (!intel_gvt_ggtt_validate_range(vgpu, start,
                                _RING_CTL_BUF_SIZE(ctl))) {
                gvt_vgpu_err("context contain invalid rb at: 0x%x\n", start);
                return ERR_PTR(-EINVAL);
        }

        workload = alloc_workload(vgpu);
        if (IS_ERR(workload))
                return workload;

        workload->engine = engine;
        workload->ctx_desc = *desc;
        workload->ring_context_gpa = ring_context_gpa;
        workload->rb_head = head;
        workload->guest_rb_head = guest_head;
        workload->rb_tail = tail;
        workload->rb_start = start;
        workload->rb_ctl = ctl;

        if (engine->id == RCS0) {
                intel_gvt_hypervisor_read_gpa(vgpu, ring_context_gpa +
                        RING_CTX_OFF(bb_per_ctx_ptr.val), &per_ctx, 4);
                intel_gvt_hypervisor_read_gpa(vgpu, ring_context_gpa +
                        RING_CTX_OFF(rcs_indirect_ctx.val), &indirect_ctx, 4);

                workload->wa_ctx.indirect_ctx.guest_gma =
                        indirect_ctx & INDIRECT_CTX_ADDR_MASK;
                workload->wa_ctx.indirect_ctx.size =
                        (indirect_ctx & INDIRECT_CTX_SIZE_MASK) *
                        CACHELINE_BYTES;

                if (workload->wa_ctx.indirect_ctx.size != 0) {
                        if (!intel_gvt_ggtt_validate_range(vgpu,
                                workload->wa_ctx.indirect_ctx.guest_gma,
                                workload->wa_ctx.indirect_ctx.size)) {
                                gvt_vgpu_err("invalid wa_ctx at: 0x%lx\n",
                                    workload->wa_ctx.indirect_ctx.guest_gma);
                                kmem_cache_free(s->workloads, workload);
                                return ERR_PTR(-EINVAL);
                        }
                }

                workload->wa_ctx.per_ctx.guest_gma =
                        per_ctx & PER_CTX_ADDR_MASK;
                workload->wa_ctx.per_ctx.valid = per_ctx & 1;
                if (workload->wa_ctx.per_ctx.valid) {
                        if (!intel_gvt_ggtt_validate_range(vgpu,
                                workload->wa_ctx.per_ctx.guest_gma,
                                CACHELINE_BYTES)) {
                                gvt_vgpu_err("invalid per_ctx at: 0x%lx\n",
                                        workload->wa_ctx.per_ctx.guest_gma);
                                kmem_cache_free(s->workloads, workload);
                                return ERR_PTR(-EINVAL);
                        }
                }
        }

        gvt_dbg_el("workload %p ring %s head %x tail %x start %x ctl %x\n",
                   workload, engine->name, head, tail, start, ctl);

        ret = prepare_mm(workload);
        if (ret) {
                kmem_cache_free(s->workloads, workload);
                return ERR_PTR(ret);
        }

        /* Only scan and shadow the first workload in the queue
         * as there is only one pre-allocated buf-obj for shadow.
         */
        if (list_empty(q)) {
                intel_wakeref_t wakeref;

                with_intel_runtime_pm(engine->gt->uncore->rpm, wakeref)
                        ret = intel_gvt_scan_and_shadow_workload(workload);
        }

        if (ret) {
                if (vgpu_is_vm_unhealthy(ret))
                        enter_failsafe_mode(vgpu, GVT_FAILSAFE_GUEST_ERR);
                intel_vgpu_destroy_workload(workload);
                return ERR_PTR(ret);
        }

        return workload;
}

/**
 * intel_vgpu_queue_workload - Qeue a vGPU workload
 * @workload: the workload to queue in
 */
void intel_vgpu_queue_workload(struct intel_vgpu_workload *workload)
{
        list_add_tail(&workload->list,
                      workload_q_head(workload->vgpu, workload->engine));
        intel_gvt_kick_schedule(workload->vgpu->gvt);
        wake_up(&workload->vgpu->gvt->scheduler.waitq[workload->engine->id]);
}