scsi: qedf: Fix a potential NULL pointer dereference

[mirror_ubuntu-artful-kernel.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 "i915_drv.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])
{
        struct execlist_mmio_pair *pdp_pair = &ring_context->pdp3_UDW;
        int i;

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

static int populate_shadow_context(struct intel_vgpu_workload *workload)
{
        struct intel_vgpu *vgpu = workload->vgpu;
        struct intel_gvt *gvt = vgpu->gvt;
        int ring_id = workload->ring_id;
        struct i915_gem_context *shadow_ctx = workload->vgpu->shadow_ctx;
        struct drm_i915_gem_object *ctx_obj =
                shadow_ctx->engine[ring_id].state->obj;
        struct execlist_ring_context *shadow_ring_context;
        struct page *page;
        void *dst;
        unsigned long context_gpa, context_page_num;
        int i;

        gvt_dbg_sched("ring id %d workload lrca %x", ring_id,
                        workload->ctx_desc.lrca);

        context_page_num = gvt->dev_priv->engine[ring_id]->context_size;

        context_page_num = context_page_num >> PAGE_SHIFT;

        if (IS_BROADWELL(gvt->dev_priv) && ring_id == RCS)
                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) <<
                                GTT_PAGE_SHIFT));
                if (context_gpa == INTEL_GVT_INVALID_ADDR) {
                        gvt_vgpu_err("Invalid guest context descriptor\n");
                        return -EINVAL;
                }

                page = i915_gem_object_get_page(ctx_obj, LRC_PPHWSP_PN + i);
                dst = kmap(page);
                intel_gvt_hypervisor_read_gpa(vgpu, context_gpa, dst,
                                GTT_PAGE_SIZE);
                kunmap(page);
                i++;
        }

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

#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)

        COPY_REG(ctx_ctrl);
        COPY_REG(ctx_timestamp);

        if (ring_id == RCS) {
                COPY_REG(bb_per_ctx_ptr);
                COPY_REG(rcs_indirect_ctx);
                COPY_REG(rcs_indirect_ctx_offset);
        }
#undef COPY_REG

        set_context_pdp_root_pointer(shadow_ring_context,
                                     workload->shadow_mm->shadow_page_table);

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

        kunmap(page);
        return 0;
}

static inline bool is_gvt_request(struct drm_i915_gem_request *req)
{
        return i915_gem_context_force_single_submission(req->ctx);
}

static int shadow_context_status_change(struct notifier_block *nb,
                unsigned long action, void *data)
{
        struct drm_i915_gem_request *req = (struct drm_i915_gem_request *)data;
        struct intel_gvt *gvt = container_of(nb, struct intel_gvt,
                                shadow_ctx_notifier_block[req->engine->id]);
        struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
        enum intel_engine_id ring_id = req->engine->id;
        struct intel_vgpu_workload *workload;

        if (!is_gvt_request(req)) {
                spin_lock_bh(&scheduler->mmio_context_lock);
                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, ring_id);
                        scheduler->engine_owner[ring_id] = NULL;
                }
                spin_unlock_bh(&scheduler->mmio_context_lock);

                return NOTIFY_OK;
        }

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

        switch (action) {
        case INTEL_CONTEXT_SCHEDULE_IN:
                spin_lock_bh(&scheduler->mmio_context_lock);
                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, ring_id);
                        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_bh(&scheduler->mmio_context_lock);
                atomic_set(&workload->shadow_ctx_active, 1);
                break;
        case INTEL_CONTEXT_SCHEDULE_OUT:
                /* If the status is -EINPROGRESS means this workload
                 * doesn't meet any issue during dispatching so when
                 * get the SCHEDULE_OUT set the status to be zero for
                 * good. If the status is NOT -EINPROGRESS means there
                 * is something wrong happened during dispatching and
                 * the status should not be set to zero
                 */
                if (workload->status == -EINPROGRESS)
                        workload->status = 0;
                atomic_set(&workload->shadow_ctx_active, 0);
                break;
        default:
                WARN_ON(1);
                return NOTIFY_OK;
        }
        wake_up(&workload->shadow_ctx_status_wq);
        return NOTIFY_OK;
}

static int dispatch_workload(struct intel_vgpu_workload *workload)
{
        int ring_id = workload->ring_id;
        struct i915_gem_context *shadow_ctx = workload->vgpu->shadow_ctx;
        struct drm_i915_private *dev_priv = workload->vgpu->gvt->dev_priv;
        struct intel_engine_cs *engine = dev_priv->engine[ring_id];
        struct drm_i915_gem_request *rq;
        struct intel_vgpu *vgpu = workload->vgpu;
        struct intel_ring *ring;
        int ret;

        gvt_dbg_sched("ring id %d prepare to dispatch workload %p\n",
                ring_id, workload);

        shadow_ctx->desc_template &= ~(0x3 << GEN8_CTX_ADDRESSING_MODE_SHIFT);
        shadow_ctx->desc_template |= workload->ctx_desc.addressing_mode <<
                                    GEN8_CTX_ADDRESSING_MODE_SHIFT;

        mutex_lock(&dev_priv->drm.struct_mutex);

        /* pin shadow context by gvt even the shadow context will be pinned
         * when i915 alloc request. That is because gvt will update the guest
         * context from shadow context when workload is completed, and at that
         * moment, i915 may already unpined the shadow context to make the
         * shadow_ctx pages invalid. So gvt need to pin itself. After update
         * the guest context, gvt can unpin the shadow_ctx safely.
         */
        ring = engine->context_pin(engine, shadow_ctx);
        if (IS_ERR(ring)) {
                ret = PTR_ERR(ring);
                gvt_vgpu_err("fail to pin shadow context\n");
                workload->status = ret;
                mutex_unlock(&dev_priv->drm.struct_mutex);
                return ret;
        }

        rq = i915_gem_request_alloc(dev_priv->engine[ring_id], shadow_ctx);
        if (IS_ERR(rq)) {
                gvt_vgpu_err("fail to allocate gem request\n");
                ret = PTR_ERR(rq);
                goto out;
        }

        gvt_dbg_sched("ring id %d get i915 gem request %p\n", ring_id, rq);

        workload->req = i915_gem_request_get(rq);

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

        if ((workload->ring_id == RCS) &&
            (workload->wa_ctx.indirect_ctx.size != 0)) {
                ret = intel_gvt_scan_and_shadow_wa_ctx(&workload->wa_ctx);
                if (ret)
                        goto out;
        }

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

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

        gvt_dbg_sched("ring id %d submit workload to i915 %p\n",
                        ring_id, workload->req);

        ret = 0;
        workload->dispatched = true;
out:
        if (ret)
                workload->status = ret;

        if (!IS_ERR_OR_NULL(rq))
                i915_add_request(rq);
        else
                engine->context_unpin(engine, shadow_ctx);

        mutex_unlock(&dev_priv->drm.struct_mutex);
        return ret;
}

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

        mutex_lock(&gvt->lock);

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

        if (scheduler->need_reschedule) {
                gvt_dbg_sched("ring id %d stop - will reschedule\n", ring_id);
                goto out;
        }

        if (list_empty(workload_q_head(scheduler->current_vgpu, ring_id)))
                goto out;

        /*
         * still have current workload, maybe the workload disptacher
         * fail to submit it for some reason, resubmit it.
         */
        if (scheduler->current_workload[ring_id]) {
                workload = scheduler->current_workload[ring_id];
                gvt_dbg_sched("ring id %d still have current workload %p\n",
                                ring_id, 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[ring_id] = container_of(
                        workload_q_head(scheduler->current_vgpu, ring_id)->next,
                        struct intel_vgpu_workload, list);

        workload = scheduler->current_workload[ring_id];

        gvt_dbg_sched("ring id %d pick new workload %p\n", ring_id, workload);

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

static void update_guest_context(struct intel_vgpu_workload *workload)
{
        struct intel_vgpu *vgpu = workload->vgpu;
        struct intel_gvt *gvt = vgpu->gvt;
        int ring_id = workload->ring_id;
        struct i915_gem_context *shadow_ctx = workload->vgpu->shadow_ctx;
        struct drm_i915_gem_object *ctx_obj =
                shadow_ctx->engine[ring_id].state->obj;
        struct execlist_ring_context *shadow_ring_context;
        struct page *page;
        void *src;
        unsigned long context_gpa, context_page_num;
        int i;

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

        context_page_num = gvt->dev_priv->engine[ring_id]->context_size;

        context_page_num = context_page_num >> PAGE_SHIFT;

        if (IS_BROADWELL(gvt->dev_priv) && ring_id == RCS)
                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) <<
                                        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, LRC_PPHWSP_PN + i);
                src = kmap(page);
                intel_gvt_hypervisor_write_gpa(vgpu, context_gpa, src,
                                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),
                        GTT_PAGE_SIZE - sizeof(*shadow_ring_context));

        kunmap(page);
}

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;
        struct intel_vgpu *vgpu;
        int event;

        mutex_lock(&gvt->lock);

        workload = scheduler->current_workload[ring_id];
        vgpu = workload->vgpu;

        /* 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 (workload->req) {
                struct drm_i915_private *dev_priv =
                        workload->vgpu->gvt->dev_priv;
                struct intel_engine_cs *engine =
                        dev_priv->engine[workload->ring_id];
                wait_event(workload->shadow_ctx_status_wq,
                           !atomic_read(&workload->shadow_ctx_active));

                i915_gem_request_put(fetch_and_zero(&workload->req));

                if (!workload->status && !vgpu->resetting) {
                        update_guest_context(workload);

                        for_each_set_bit(event, workload->pending_events,
                                         INTEL_GVT_EVENT_MAX)
                                intel_vgpu_trigger_virtual_event(vgpu, event);
                }
                mutex_lock(&dev_priv->drm.struct_mutex);
                /* unpin shadow ctx as the shadow_ctx update is done */
                engine->context_unpin(engine, workload->vgpu->shadow_ctx);
                mutex_unlock(&dev_priv->drm.struct_mutex);
        }

        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);
        workload->complete(workload);

        atomic_dec(&vgpu->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->lock);
}

struct workload_thread_param {
        struct intel_gvt *gvt;
        int ring_id;
};

static DEFINE_MUTEX(scheduler_mutex);

static int workload_thread(void *priv)
{
        struct workload_thread_param *p = (struct workload_thread_param *)priv;
        struct intel_gvt *gvt = p->gvt;
        int ring_id = p->ring_id;
        struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
        struct intel_vgpu_workload *workload = NULL;
        struct intel_vgpu *vgpu = NULL;
        int ret;
        bool need_force_wake = IS_SKYLAKE(gvt->dev_priv)
                        || IS_KABYLAKE(gvt->dev_priv);
        DEFINE_WAIT_FUNC(wait, woken_wake_function);

        kfree(p);

        gvt_dbg_core("workload thread for ring %d started\n", ring_id);

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

                if (!workload)
                        break;

                mutex_lock(&scheduler_mutex);

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

                intel_runtime_pm_get(gvt->dev_priv);

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

                if (need_force_wake)
                        intel_uncore_forcewake_get(gvt->dev_priv,
                                        FORCEWAKE_ALL);

                mutex_lock(&gvt->lock);
                ret = dispatch_workload(workload);
                mutex_unlock(&gvt->lock);

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

                gvt_dbg_sched("ring id %d wait workload %p\n",
                                workload->ring_id, workload);
                i915_wait_request(workload->req, 0, MAX_SCHEDULE_TIMEOUT);

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

                complete_current_workload(gvt, ring_id);

                if (need_force_wake)
                        intel_uncore_forcewake_put(gvt->dev_priv,
                                        FORCEWAKE_ALL);

                intel_runtime_pm_put(gvt->dev_priv);

                mutex_unlock(&scheduler_mutex);

        }
        return 0;
}

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

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

                wait_event(scheduler->workload_complete_wq,
                                !atomic_read(&vgpu->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->dev_priv, 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 workload_thread_param *param = NULL;
        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->dev_priv, i) {
                init_waitqueue_head(&scheduler->waitq[i]);

                param = kzalloc(sizeof(*param), GFP_KERNEL);
                if (!param) {
                        ret = -ENOMEM;
                        goto err;
                }

                param->gvt = gvt;
                param->ring_id = i;

                scheduler->thread[i] = kthread_run(workload_thread, param,
                        "gvt workload %d", i);
                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);
        kfree(param);
        param = NULL;
        return ret;
}

void intel_vgpu_clean_gvt_context(struct intel_vgpu *vgpu)
{
        i915_gem_context_put_unlocked(vgpu->shadow_ctx);
}

int intel_vgpu_init_gvt_context(struct intel_vgpu *vgpu)
{
        atomic_set(&vgpu->running_workload_num, 0);

        vgpu->shadow_ctx = i915_gem_context_create_gvt(
                        &vgpu->gvt->dev_priv->drm);
        if (IS_ERR(vgpu->shadow_ctx))
                return PTR_ERR(vgpu->shadow_ctx);

        vgpu->shadow_ctx->engine[RCS].initialised = true;

        return 0;
}