/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright © 2011-2012 Intel Corporation
 */

/*
 * This file implements HW context support. On gen5+ a HW context consists of an
 * opaque GPU object which is referenced at times of context saves and restores.
 * With RC6 enabled, the context is also referenced as the GPU enters and exists
 * from RC6 (GPU has it's own internal power context, except on gen5). Though
 * something like a context does exist for the media ring, the code only
 * supports contexts for the render ring.
 *
 * In software, there is a distinction between contexts created by the user,
 * and the default HW context. The default HW context is used by GPU clients
 * that do not request setup of their own hardware context. The default
 * context's state is never restored to help prevent programming errors. This
 * would happen if a client ran and piggy-backed off another clients GPU state.
 * The default context only exists to give the GPU some offset to load as the
 * current to invoke a save of the context we actually care about. In fact, the
 * code could likely be constructed, albeit in a more complicated fashion, to
 * never use the default context, though that limits the driver's ability to
 * swap out, and/or destroy other contexts.
 *
 * All other contexts are created as a request by the GPU client. These contexts
 * store GPU state, and thus allow GPU clients to not re-emit state (and
 * potentially query certain state) at any time. The kernel driver makes
 * certain that the appropriate commands are inserted.
 *
 * The context life cycle is semi-complicated in that context BOs may live
 * longer than the context itself because of the way the hardware, and object
 * tracking works. Below is a very crude representation of the state machine
 * describing the context life.
 *                                         refcount     pincount     active
 * S0: initial state                          0            0           0
 * S1: context created                        1            0           0
 * S2: context is currently running           2            1           X
 * S3: GPU referenced, but not current        2            0           1
 * S4: context is current, but destroyed      1            1           0
 * S5: like S3, but destroyed                 1            0           1
 *
 * The most common (but not all) transitions:
 * S0->S1: client creates a context
 * S1->S2: client submits execbuf with context
 * S2->S3: other clients submits execbuf with context
 * S3->S1: context object was retired
 * S3->S2: clients submits another execbuf
 * S2->S4: context destroy called with current context
 * S3->S5->S0: destroy path
 * S4->S5->S0: destroy path on current context
 *
 * There are two confusing terms used above:
 *  The "current context" means the context which is currently running on the
 *  GPU. The GPU has loaded its state already and has stored away the gtt
 *  offset of the BO. The GPU is not actively referencing the data at this
 *  offset, but it will on the next context switch. The only way to avoid this
 *  is to do a GPU reset.
 *
 *  An "active context' is one which was previously the "current context" and is
 *  on the active list waiting for the next context switch to occur. Until this
 *  happens, the object must remain at the same gtt offset. It is therefore
 *  possible to destroy a context, but it is still active.
 *
 */

#include <linux/log2.h>
#include <linux/nospec.h>

#include <drm/drm_syncobj.h>

#include "gt/gen6_ppgtt.h"
#include "gt/intel_context.h"
#include "gt/intel_context_param.h"
#include "gt/intel_engine_heartbeat.h"
#include "gt/intel_engine_user.h"
#include "gt/intel_gpu_commands.h"
#include "gt/intel_ring.h"

#include "i915_gem_context.h"
#include "i915_trace.h"
#include "i915_user_extensions.h"

#define ALL_L3_SLICES(dev) (1 << NUM_L3_SLICES(dev)) - 1

static struct kmem_cache *slab_luts;

struct i915_lut_handle *i915_lut_handle_alloc(void)
{
        return kmem_cache_alloc(slab_luts, GFP_KERNEL);
}

void i915_lut_handle_free(struct i915_lut_handle *lut)
{
        return kmem_cache_free(slab_luts, lut);
}

static void lut_close(struct i915_gem_context *ctx)
{
        struct radix_tree_iter iter;
        void __rcu **slot;

        mutex_lock(&ctx->lut_mutex);
        rcu_read_lock();
        radix_tree_for_each_slot(slot, &ctx->handles_vma, &iter, 0) {
                struct i915_vma *vma = rcu_dereference_raw(*slot);
                struct drm_i915_gem_object *obj = vma->obj;
                struct i915_lut_handle *lut;

                if (!kref_get_unless_zero(&obj->base.refcount))
                        continue;

                spin_lock(&obj->lut_lock);
                list_for_each_entry(lut, &obj->lut_list, obj_link) {
                        if (lut->ctx != ctx)
                                continue;

                        if (lut->handle != iter.index)
                                continue;

                        list_del(&lut->obj_link);
                        break;
                }
                spin_unlock(&obj->lut_lock);

                if (&lut->obj_link != &obj->lut_list) {
                        i915_lut_handle_free(lut);
                        radix_tree_iter_delete(&ctx->handles_vma, &iter, slot);
                        i915_vma_close(vma);
                        i915_gem_object_put(obj);
                }

                i915_gem_object_put(obj);
        }
        rcu_read_unlock();
        mutex_unlock(&ctx->lut_mutex);
}

static struct intel_context *
lookup_user_engine(struct i915_gem_context *ctx,
                   unsigned long flags,
                   const struct i915_engine_class_instance *ci)
#define LOOKUP_USER_INDEX BIT(0)
{
        int idx;

        if (!!(flags & LOOKUP_USER_INDEX) != i915_gem_context_user_engines(ctx))
                return ERR_PTR(-EINVAL);

        if (!i915_gem_context_user_engines(ctx)) {
                struct intel_engine_cs *engine;

                engine = intel_engine_lookup_user(ctx->i915,
                                                  ci->engine_class,
                                                  ci->engine_instance);
                if (!engine)
                        return ERR_PTR(-EINVAL);

                idx = engine->legacy_idx;
        } else {
                idx = ci->engine_instance;
        }

        return i915_gem_context_get_engine(ctx, idx);
}

static int validate_priority(struct drm_i915_private *i915,
                             const struct drm_i915_gem_context_param *args)
{
        s64 priority = args->value;

        if (args->size)
                return -EINVAL;

        if (!(i915->caps.scheduler & I915_SCHEDULER_CAP_PRIORITY))
                return -ENODEV;

        if (priority > I915_CONTEXT_MAX_USER_PRIORITY ||
            priority < I915_CONTEXT_MIN_USER_PRIORITY)
                return -EINVAL;

        if (priority > I915_CONTEXT_DEFAULT_PRIORITY &&
            !capable(CAP_SYS_NICE))
                return -EPERM;

        return 0;
}

static void proto_context_close(struct i915_gem_proto_context *pc)
{
        int i;

        if (pc->vm)
                i915_vm_put(pc->vm);
        if (pc->user_engines) {
                for (i = 0; i < pc->num_user_engines; i++)
                        kfree(pc->user_engines[i].siblings);
                kfree(pc->user_engines);
        }
        kfree(pc);
}

static int proto_context_set_persistence(struct drm_i915_private *i915,
                                         struct i915_gem_proto_context *pc,
                                         bool persist)
{
        if (persist) {
                /*
                 * Only contexts that are short-lived [that will expire or be
                 * reset] are allowed to survive past termination. We require
                 * hangcheck to ensure that the persistent requests are healthy.
                 */
                if (!i915->params.enable_hangcheck)
                        return -EINVAL;

                pc->user_flags |= BIT(UCONTEXT_PERSISTENCE);
        } else {
                /* To cancel a context we use "preempt-to-idle" */
                if (!(i915->caps.scheduler & I915_SCHEDULER_CAP_PREEMPTION))
                        return -ENODEV;

                /*
                 * If the cancel fails, we then need to reset, cleanly!
                 *
                 * If the per-engine reset fails, all hope is lost! We resort
                 * to a full GPU reset in that unlikely case, but realistically
                 * if the engine could not reset, the full reset does not fare
                 * much better. The damage has been done.
                 *
                 * However, if we cannot reset an engine by itself, we cannot
                 * cleanup a hanging persistent context without causing
                 * colateral damage, and we should not pretend we can by
                 * exposing the interface.
                 */
                if (!intel_has_reset_engine(&i915->gt))
                        return -ENODEV;

                pc->user_flags &= ~BIT(UCONTEXT_PERSISTENCE);
        }

        return 0;
}

static struct i915_gem_proto_context *
proto_context_create(struct drm_i915_private *i915, unsigned int flags)
{
        struct i915_gem_proto_context *pc, *err;

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

        pc->num_user_engines = -1;
        pc->user_engines = NULL;
        pc->user_flags = BIT(UCONTEXT_BANNABLE) |
                         BIT(UCONTEXT_RECOVERABLE);
        if (i915->params.enable_hangcheck)
                pc->user_flags |= BIT(UCONTEXT_PERSISTENCE);
        pc->sched.priority = I915_PRIORITY_NORMAL;

        if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE) {
                if (!HAS_EXECLISTS(i915)) {
                        err = ERR_PTR(-EINVAL);
                        goto proto_close;
                }
                pc->single_timeline = true;
        }

        return pc;

proto_close:
        proto_context_close(pc);
        return err;
}

static int proto_context_register_locked(struct drm_i915_file_private *fpriv,
                                         struct i915_gem_proto_context *pc,
                                         u32 *id)
{
        int ret;
        void *old;

        lockdep_assert_held(&fpriv->proto_context_lock);

        ret = xa_alloc(&fpriv->context_xa, id, NULL, xa_limit_32b, GFP_KERNEL);
        if (ret)
                return ret;

        old = xa_store(&fpriv->proto_context_xa, *id, pc, GFP_KERNEL);
        if (xa_is_err(old)) {
                xa_erase(&fpriv->context_xa, *id);
                return xa_err(old);
        }
        WARN_ON(old);

        return 0;
}

static int proto_context_register(struct drm_i915_file_private *fpriv,
                                  struct i915_gem_proto_context *pc,
                                  u32 *id)
{
        int ret;

        mutex_lock(&fpriv->proto_context_lock);
        ret = proto_context_register_locked(fpriv, pc, id);
        mutex_unlock(&fpriv->proto_context_lock);

        return ret;
}

static int set_proto_ctx_vm(struct drm_i915_file_private *fpriv,
                            struct i915_gem_proto_context *pc,
                            const struct drm_i915_gem_context_param *args)
{
        struct drm_i915_private *i915 = fpriv->dev_priv;
        struct i915_address_space *vm;

        if (args->size)
                return -EINVAL;

        if (!HAS_FULL_PPGTT(i915))
                return -ENODEV;

        if (upper_32_bits(args->value))
                return -ENOENT;

        vm = i915_gem_vm_lookup(fpriv, args->value);
        if (!vm)
                return -ENOENT;

        if (pc->vm)
                i915_vm_put(pc->vm);
        pc->vm = vm;

        return 0;
}

struct set_proto_ctx_engines {
        struct drm_i915_private *i915;
        unsigned num_engines;
        struct i915_gem_proto_engine *engines;
};

static int
set_proto_ctx_engines_balance(struct i915_user_extension __user *base,
                              void *data)
{
        struct i915_context_engines_load_balance __user *ext =
                container_of_user(base, typeof(*ext), base);
        const struct set_proto_ctx_engines *set = data;
        struct drm_i915_private *i915 = set->i915;
        struct intel_engine_cs **siblings;
        u16 num_siblings, idx;
        unsigned int n;
        int err;

        if (!HAS_EXECLISTS(i915))
                return -ENODEV;

        if (get_user(idx, &ext->engine_index))
                return -EFAULT;

        if (idx >= set->num_engines) {
                drm_dbg(&i915->drm, "Invalid placement value, %d >= %d\n",
                        idx, set->num_engines);
                return -EINVAL;
        }

        idx = array_index_nospec(idx, set->num_engines);
        if (set->engines[idx].type != I915_GEM_ENGINE_TYPE_INVALID) {
                drm_dbg(&i915->drm,
                        "Invalid placement[%d], already occupied\n", idx);
                return -EEXIST;
        }

        if (get_user(num_siblings, &ext->num_siblings))
                return -EFAULT;

        err = check_user_mbz(&ext->flags);
        if (err)
                return err;

        err = check_user_mbz(&ext->mbz64);
        if (err)
                return err;

        if (num_siblings == 0)
                return 0;

        siblings = kmalloc_array(num_siblings, sizeof(*siblings), GFP_KERNEL);
        if (!siblings)
                return -ENOMEM;

        for (n = 0; n < num_siblings; n++) {
                struct i915_engine_class_instance ci;

                if (copy_from_user(&ci, &ext->engines[n], sizeof(ci))) {
                        err = -EFAULT;
                        goto err_siblings;
                }

                siblings[n] = intel_engine_lookup_user(i915,
                                                       ci.engine_class,
                                                       ci.engine_instance);
                if (!siblings[n]) {
                        drm_dbg(&i915->drm,
                                "Invalid sibling[%d]: { class:%d, inst:%d }\n",
                                n, ci.engine_class, ci.engine_instance);
                        err = -EINVAL;
                        goto err_siblings;
                }
        }

        if (num_siblings == 1) {
                set->engines[idx].type = I915_GEM_ENGINE_TYPE_PHYSICAL;
                set->engines[idx].engine = siblings[0];
                kfree(siblings);
        } else {
                set->engines[idx].type = I915_GEM_ENGINE_TYPE_BALANCED;
                set->engines[idx].num_siblings = num_siblings;
                set->engines[idx].siblings = siblings;
        }

        return 0;

err_siblings:
        kfree(siblings);

        return err;
}

static int
set_proto_ctx_engines_bond(struct i915_user_extension __user *base, void *data)
{
        struct i915_context_engines_bond __user *ext =
                container_of_user(base, typeof(*ext), base);
        const struct set_proto_ctx_engines *set = data;
        struct drm_i915_private *i915 = set->i915;
        struct i915_engine_class_instance ci;
        struct intel_engine_cs *master;
        u16 idx, num_bonds;
        int err, n;

        if (get_user(idx, &ext->virtual_index))
                return -EFAULT;

        if (idx >= set->num_engines) {
                drm_dbg(&i915->drm,
                        "Invalid index for virtual engine: %d >= %d\n",
                        idx, set->num_engines);
                return -EINVAL;
        }

        idx = array_index_nospec(idx, set->num_engines);
        if (set->engines[idx].type == I915_GEM_ENGINE_TYPE_INVALID) {
                drm_dbg(&i915->drm, "Invalid engine at %d\n", idx);
                return -EINVAL;
        }

        if (set->engines[idx].type != I915_GEM_ENGINE_TYPE_PHYSICAL) {
                drm_dbg(&i915->drm,
                        "Bonding with virtual engines not allowed\n");
                return -EINVAL;
        }

        err = check_user_mbz(&ext->flags);
        if (err)
                return err;

        for (n = 0; n < ARRAY_SIZE(ext->mbz64); n++) {
                err = check_user_mbz(&ext->mbz64[n]);
                if (err)
                        return err;
        }

        if (copy_from_user(&ci, &ext->master, sizeof(ci)))
                return -EFAULT;

        master = intel_engine_lookup_user(i915,
                                          ci.engine_class,
                                          ci.engine_instance);
        if (!master) {
                drm_dbg(&i915->drm,
                        "Unrecognised master engine: { class:%u, instance:%u }\n",
                        ci.engine_class, ci.engine_instance);
                return -EINVAL;
        }

        if (intel_engine_uses_guc(master)) {
                DRM_DEBUG("bonding extension not supported with GuC submission");
                return -ENODEV;
        }

        if (get_user(num_bonds, &ext->num_bonds))
                return -EFAULT;

        for (n = 0; n < num_bonds; n++) {
                struct intel_engine_cs *bond;

                if (copy_from_user(&ci, &ext->engines[n], sizeof(ci)))
                        return -EFAULT;

                bond = intel_engine_lookup_user(i915,
                                                ci.engine_class,
                                                ci.engine_instance);
                if (!bond) {
                        drm_dbg(&i915->drm,
                                "Unrecognised engine[%d] for bonding: { class:%d, instance: %d }\n",
                                n, ci.engine_class, ci.engine_instance);
                        return -EINVAL;
                }
        }

        return 0;
}

static const i915_user_extension_fn set_proto_ctx_engines_extensions[] = {
        [I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE] = set_proto_ctx_engines_balance,
        [I915_CONTEXT_ENGINES_EXT_BOND] = set_proto_ctx_engines_bond,
};

static int set_proto_ctx_engines(struct drm_i915_file_private *fpriv,
                                 struct i915_gem_proto_context *pc,
                                 const struct drm_i915_gem_context_param *args)
{
        struct drm_i915_private *i915 = fpriv->dev_priv;
        struct set_proto_ctx_engines set = { .i915 = i915 };
        struct i915_context_param_engines __user *user =
                u64_to_user_ptr(args->value);
        unsigned int n;
        u64 extensions;
        int err;

        if (pc->num_user_engines >= 0) {
                drm_dbg(&i915->drm, "Cannot set engines twice");
                return -EINVAL;
        }

        if (args->size < sizeof(*user) ||
            !IS_ALIGNED(args->size - sizeof(*user), sizeof(*user->engines))) {
                drm_dbg(&i915->drm, "Invalid size for engine array: %d\n",
                        args->size);
                return -EINVAL;
        }

        set.num_engines = (args->size - sizeof(*user)) / sizeof(*user->engines);
        /* RING_MASK has no shift so we can use it directly here */
        if (set.num_engines > I915_EXEC_RING_MASK + 1)
                return -EINVAL;

        set.engines = kmalloc_array(set.num_engines, sizeof(*set.engines), GFP_KERNEL);
        if (!set.engines)
                return -ENOMEM;

        for (n = 0; n < set.num_engines; n++) {
                struct i915_engine_class_instance ci;
                struct intel_engine_cs *engine;

                if (copy_from_user(&ci, &user->engines[n], sizeof(ci))) {
                        kfree(set.engines);
                        return -EFAULT;
                }

                memset(&set.engines[n], 0, sizeof(set.engines[n]));

                if (ci.engine_class == (u16)I915_ENGINE_CLASS_INVALID &&
                    ci.engine_instance == (u16)I915_ENGINE_CLASS_INVALID_NONE)
                        continue;

                engine = intel_engine_lookup_user(i915,
                                                  ci.engine_class,
                                                  ci.engine_instance);
                if (!engine) {
                        drm_dbg(&i915->drm,
                                "Invalid engine[%d]: { class:%d, instance:%d }\n",
                                n, ci.engine_class, ci.engine_instance);
                        kfree(set.engines);
                        return -ENOENT;
                }

                set.engines[n].type = I915_GEM_ENGINE_TYPE_PHYSICAL;
                set.engines[n].engine = engine;
        }

        err = -EFAULT;
        if (!get_user(extensions, &user->extensions))
                err = i915_user_extensions(u64_to_user_ptr(extensions),
                                           set_proto_ctx_engines_extensions,
                                           ARRAY_SIZE(set_proto_ctx_engines_extensions),
                                           &set);
        if (err) {
                kfree(set.engines);
                return err;
        }

        pc->num_user_engines = set.num_engines;
        pc->user_engines = set.engines;

        return 0;
}

static int set_proto_ctx_sseu(struct drm_i915_file_private *fpriv,
                              struct i915_gem_proto_context *pc,
                              struct drm_i915_gem_context_param *args)
{
        struct drm_i915_private *i915 = fpriv->dev_priv;
        struct drm_i915_gem_context_param_sseu user_sseu;
        struct intel_sseu *sseu;
        int ret;

        if (args->size < sizeof(user_sseu))
                return -EINVAL;

        if (GRAPHICS_VER(i915) != 11)
                return -ENODEV;

        if (copy_from_user(&user_sseu, u64_to_user_ptr(args->value),
                           sizeof(user_sseu)))
                return -EFAULT;

        if (user_sseu.rsvd)
                return -EINVAL;

        if (user_sseu.flags & ~(I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX))
                return -EINVAL;

        if (!!(user_sseu.flags & I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX) != (pc->num_user_engines >= 0))
                return -EINVAL;

        if (pc->num_user_engines >= 0) {
                int idx = user_sseu.engine.engine_instance;
                struct i915_gem_proto_engine *pe;

                if (idx >= pc->num_user_engines)
                        return -EINVAL;

                pe = &pc->user_engines[idx];

                /* Only render engine supports RPCS configuration. */
                if (pe->engine->class != RENDER_CLASS)
                        return -EINVAL;

                sseu = &pe->sseu;
        } else {
                /* Only render engine supports RPCS configuration. */
                if (user_sseu.engine.engine_class != I915_ENGINE_CLASS_RENDER)
                        return -EINVAL;

                /* There is only one render engine */
                if (user_sseu.engine.engine_instance != 0)
                        return -EINVAL;

                sseu = &pc->legacy_rcs_sseu;
        }

        ret = i915_gem_user_to_context_sseu(&i915->gt, &user_sseu, sseu);
        if (ret)
                return ret;

        args->size = sizeof(user_sseu);

        return 0;
}

static int set_proto_ctx_param(struct drm_i915_file_private *fpriv,
                               struct i915_gem_proto_context *pc,
                               struct drm_i915_gem_context_param *args)
{
        int ret = 0;

        switch (args->param) {
        case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
                if (args->size)
                        ret = -EINVAL;
                else if (args->value)
                        pc->user_flags |= BIT(UCONTEXT_NO_ERROR_CAPTURE);
                else
                        pc->user_flags &= ~BIT(UCONTEXT_NO_ERROR_CAPTURE);
                break;

        case I915_CONTEXT_PARAM_BANNABLE:
                if (args->size)
                        ret = -EINVAL;
                else if (!capable(CAP_SYS_ADMIN) && !args->value)
                        ret = -EPERM;
                else if (args->value)
                        pc->user_flags |= BIT(UCONTEXT_BANNABLE);
                else
                        pc->user_flags &= ~BIT(UCONTEXT_BANNABLE);
                break;

        case I915_CONTEXT_PARAM_RECOVERABLE:
                if (args->size)
                        ret = -EINVAL;
                else if (args->value)
                        pc->user_flags |= BIT(UCONTEXT_RECOVERABLE);
                else
                        pc->user_flags &= ~BIT(UCONTEXT_RECOVERABLE);
                break;

        case I915_CONTEXT_PARAM_PRIORITY:
                ret = validate_priority(fpriv->dev_priv, args);
                if (!ret)
                        pc->sched.priority = args->value;
                break;

        case I915_CONTEXT_PARAM_SSEU:
                ret = set_proto_ctx_sseu(fpriv, pc, args);
                break;

        case I915_CONTEXT_PARAM_VM:
                ret = set_proto_ctx_vm(fpriv, pc, args);
                break;

        case I915_CONTEXT_PARAM_ENGINES:
                ret = set_proto_ctx_engines(fpriv, pc, args);
                break;

        case I915_CONTEXT_PARAM_PERSISTENCE:
                if (args->size)
                        ret = -EINVAL;
                ret = proto_context_set_persistence(fpriv->dev_priv, pc,
                                                    args->value);
                break;

        case I915_CONTEXT_PARAM_NO_ZEROMAP:
        case I915_CONTEXT_PARAM_BAN_PERIOD:
        case I915_CONTEXT_PARAM_RINGSIZE:
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static struct i915_address_space *
context_get_vm_rcu(struct i915_gem_context *ctx)
{
        GEM_BUG_ON(!rcu_access_pointer(ctx->vm));

        do {
                struct i915_address_space *vm;

                /*
                 * We do not allow downgrading from full-ppgtt [to a shared
                 * global gtt], so ctx->vm cannot become NULL.
                 */
                vm = rcu_dereference(ctx->vm);
                if (!kref_get_unless_zero(&vm->ref))
                        continue;

                /*
                 * This ppgtt may have be reallocated between
                 * the read and the kref, and reassigned to a third
                 * context. In order to avoid inadvertent sharing
                 * of this ppgtt with that third context (and not
                 * src), we have to confirm that we have the same
                 * ppgtt after passing through the strong memory
                 * barrier implied by a successful
                 * kref_get_unless_zero().
                 *
                 * Once we have acquired the current ppgtt of ctx,
                 * we no longer care if it is released from ctx, as
                 * it cannot be reallocated elsewhere.
                 */

                if (vm == rcu_access_pointer(ctx->vm))
                        return rcu_pointer_handoff(vm);

                i915_vm_put(vm);
        } while (1);
}

static int intel_context_set_gem(struct intel_context *ce,
                                 struct i915_gem_context *ctx,
                                 struct intel_sseu sseu)
{
        int ret = 0;

        GEM_BUG_ON(rcu_access_pointer(ce->gem_context));
        RCU_INIT_POINTER(ce->gem_context, ctx);

        ce->ring_size = SZ_16K;

        if (rcu_access_pointer(ctx->vm)) {
                struct i915_address_space *vm;

                rcu_read_lock();
                vm = context_get_vm_rcu(ctx); /* hmm */
                rcu_read_unlock();

                i915_vm_put(ce->vm);
                ce->vm = vm;
        }

        if (ctx->sched.priority >= I915_PRIORITY_NORMAL &&
            intel_engine_has_timeslices(ce->engine) &&
            intel_engine_has_semaphores(ce->engine))
                __set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags);

        if (IS_ACTIVE(CONFIG_DRM_I915_REQUEST_TIMEOUT) &&
            ctx->i915->params.request_timeout_ms) {
                unsigned int timeout_ms = ctx->i915->params.request_timeout_ms;

                intel_context_set_watchdog_us(ce, (u64)timeout_ms * 1000);
        }

        /* A valid SSEU has no zero fields */
        if (sseu.slice_mask && !WARN_ON(ce->engine->class != RENDER_CLASS))
                ret = intel_context_reconfigure_sseu(ce, sseu);

        return ret;
}

static void __free_engines(struct i915_gem_engines *e, unsigned int count)
{
        while (count--) {
                if (!e->engines[count])
                        continue;

                intel_context_put(e->engines[count]);
        }
        kfree(e);
}

static void free_engines(struct i915_gem_engines *e)
{
        __free_engines(e, e->num_engines);
}

static void free_engines_rcu(struct rcu_head *rcu)
{
        struct i915_gem_engines *engines =
                container_of(rcu, struct i915_gem_engines, rcu);

        i915_sw_fence_fini(&engines->fence);
        free_engines(engines);
}

static int __i915_sw_fence_call
engines_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
{
        struct i915_gem_engines *engines =
                container_of(fence, typeof(*engines), fence);

        switch (state) {
        case FENCE_COMPLETE:
                if (!list_empty(&engines->link)) {
                        struct i915_gem_context *ctx = engines->ctx;
                        unsigned long flags;

                        spin_lock_irqsave(&ctx->stale.lock, flags);
                        list_del(&engines->link);
                        spin_unlock_irqrestore(&ctx->stale.lock, flags);
                }
                i915_gem_context_put(engines->ctx);
                break;

        case FENCE_FREE:
                init_rcu_head(&engines->rcu);
                call_rcu(&engines->rcu, free_engines_rcu);
                break;
        }

        return NOTIFY_DONE;
}

static struct i915_gem_engines *alloc_engines(unsigned int count)
{
        struct i915_gem_engines *e;

        e = kzalloc(struct_size(e, engines, count), GFP_KERNEL);
        if (!e)
                return NULL;

        i915_sw_fence_init(&e->fence, engines_notify);
        return e;
}

static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx,
                                                struct intel_sseu rcs_sseu)
{
        const struct intel_gt *gt = &ctx->i915->gt;
        struct intel_engine_cs *engine;
        struct i915_gem_engines *e, *err;
        enum intel_engine_id id;

        e = alloc_engines(I915_NUM_ENGINES);
        if (!e)
                return ERR_PTR(-ENOMEM);

        for_each_engine(engine, gt, id) {
                struct intel_context *ce;
                struct intel_sseu sseu = {};
                int ret;

                if (engine->legacy_idx == INVALID_ENGINE)
                        continue;

                GEM_BUG_ON(engine->legacy_idx >= I915_NUM_ENGINES);
                GEM_BUG_ON(e->engines[engine->legacy_idx]);

                ce = intel_context_create(engine);
                if (IS_ERR(ce)) {
                        err = ERR_CAST(ce);
                        goto free_engines;
                }

                e->engines[engine->legacy_idx] = ce;
                e->num_engines = max(e->num_engines, engine->legacy_idx + 1);

                if (engine->class == RENDER_CLASS)
                        sseu = rcs_sseu;

                ret = intel_context_set_gem(ce, ctx, sseu);
                if (ret) {
                        err = ERR_PTR(ret);
                        goto free_engines;
                }

        }

        return e;

free_engines:
        free_engines(e);
        return err;
}

static struct i915_gem_engines *user_engines(struct i915_gem_context *ctx,
                                             unsigned int num_engines,
                                             struct i915_gem_proto_engine *pe)
{
        struct i915_gem_engines *e, *err;
        unsigned int n;

        e = alloc_engines(num_engines);
        if (!e)
                return ERR_PTR(-ENOMEM);
        e->num_engines = num_engines;

        for (n = 0; n < num_engines; n++) {
                struct intel_context *ce;
                int ret;

                switch (pe[n].type) {
                case I915_GEM_ENGINE_TYPE_PHYSICAL:
                        ce = intel_context_create(pe[n].engine);
                        break;

                case I915_GEM_ENGINE_TYPE_BALANCED:
                        ce = intel_engine_create_virtual(pe[n].siblings,
                                                         pe[n].num_siblings);
                        break;

                case I915_GEM_ENGINE_TYPE_INVALID:
                default:
                        GEM_WARN_ON(pe[n].type != I915_GEM_ENGINE_TYPE_INVALID);
                        continue;
                }

                if (IS_ERR(ce)) {
                        err = ERR_CAST(ce);
                        goto free_engines;
                }

                e->engines[n] = ce;

                ret = intel_context_set_gem(ce, ctx, pe->sseu);
                if (ret) {
                        err = ERR_PTR(ret);
                        goto free_engines;
                }
        }

        return e;

free_engines:
        free_engines(e);
        return err;
}

void i915_gem_context_release(struct kref *ref)
{
        struct i915_gem_context *ctx = container_of(ref, typeof(*ctx), ref);

        trace_i915_context_free(ctx);
        GEM_BUG_ON(!i915_gem_context_is_closed(ctx));

        if (ctx->syncobj)
                drm_syncobj_put(ctx->syncobj);

        mutex_destroy(&ctx->engines_mutex);
        mutex_destroy(&ctx->lut_mutex);

        put_pid(ctx->pid);
        mutex_destroy(&ctx->mutex);

        kfree_rcu(ctx, rcu);
}

static inline struct i915_gem_engines *
__context_engines_static(const struct i915_gem_context *ctx)
{
        return rcu_dereference_protected(ctx->engines, true);
}

static void __reset_context(struct i915_gem_context *ctx,
                            struct intel_engine_cs *engine)
{
        intel_gt_handle_error(engine->gt, engine->mask, 0,
                              "context closure in %s", ctx->name);
}

static bool __cancel_engine(struct intel_engine_cs *engine)
{
        /*
         * Send a "high priority pulse" down the engine to cause the
         * current request to be momentarily preempted. (If it fails to
         * be preempted, it will be reset). As we have marked our context
         * as banned, any incomplete request, including any running, will
         * be skipped following the preemption.
         *
         * If there is no hangchecking (one of the reasons why we try to
         * cancel the context) and no forced preemption, there may be no
         * means by which we reset the GPU and evict the persistent hog.
         * Ergo if we are unable to inject a preemptive pulse that can
         * kill the banned context, we fallback to doing a local reset
         * instead.
         */
        return intel_engine_pulse(engine) == 0;
}

static struct intel_engine_cs *active_engine(struct intel_context *ce)
{
        struct intel_engine_cs *engine = NULL;
        struct i915_request *rq;

        if (intel_context_has_inflight(ce))
                return intel_context_inflight(ce);

        if (!ce->timeline)
                return NULL;

        /*
         * rq->link is only SLAB_TYPESAFE_BY_RCU, we need to hold a reference
         * to the request to prevent it being transferred to a new timeline
         * (and onto a new timeline->requests list).
         */
        rcu_read_lock();
        list_for_each_entry_reverse(rq, &ce->timeline->requests, link) {
                bool found;

                /* timeline is already completed upto this point? */
                if (!i915_request_get_rcu(rq))
                        break;

                /* Check with the backend if the request is inflight */
                found = true;
                if (likely(rcu_access_pointer(rq->timeline) == ce->timeline))
                        found = i915_request_active_engine(rq, &engine);

                i915_request_put(rq);
                if (found)
                        break;
        }
        rcu_read_unlock();

        return engine;
}

static void kill_engines(struct i915_gem_engines *engines, bool ban)
{
        struct i915_gem_engines_iter it;
        struct intel_context *ce;

        /*
         * Map the user's engine back to the actual engines; one virtual
         * engine will be mapped to multiple engines, and using ctx->engine[]
         * the same engine may be have multiple instances in the user's map.
         * However, we only care about pending requests, so only include
         * engines on which there are incomplete requests.
         */
        for_each_gem_engine(ce, engines, it) {
                struct intel_engine_cs *engine;

                if (ban && intel_context_ban(ce, NULL))
                        continue;

                /*
                 * Check the current active state of this context; if we
                 * are currently executing on the GPU we need to evict
                 * ourselves. On the other hand, if we haven't yet been
                 * submitted to the GPU or if everything is complete,
                 * we have nothing to do.
                 */
                engine = active_engine(ce);

                /* First attempt to gracefully cancel the context */
                if (engine && !__cancel_engine(engine) && ban)
                        /*
                         * If we are unable to send a preemptive pulse to bump
                         * the context from the GPU, we have to resort to a full
                         * reset. We hope the collateral damage is worth it.
                         */
                        __reset_context(engines->ctx, engine);
        }
}

static void kill_context(struct i915_gem_context *ctx)
{
        bool ban = (!i915_gem_context_is_persistent(ctx) ||
                    !ctx->i915->params.enable_hangcheck);
        struct i915_gem_engines *pos, *next;

        spin_lock_irq(&ctx->stale.lock);
        GEM_BUG_ON(!i915_gem_context_is_closed(ctx));
        list_for_each_entry_safe(pos, next, &ctx->stale.engines, link) {
                if (!i915_sw_fence_await(&pos->fence)) {
                        list_del_init(&pos->link);
                        continue;
                }

                spin_unlock_irq(&ctx->stale.lock);

                kill_engines(pos, ban);

                spin_lock_irq(&ctx->stale.lock);
                GEM_BUG_ON(i915_sw_fence_signaled(&pos->fence));
                list_safe_reset_next(pos, next, link);
                list_del_init(&pos->link); /* decouple from FENCE_COMPLETE */

                i915_sw_fence_complete(&pos->fence);
        }
        spin_unlock_irq(&ctx->stale.lock);
}

static void engines_idle_release(struct i915_gem_context *ctx,
                                 struct i915_gem_engines *engines)
{
        struct i915_gem_engines_iter it;
        struct intel_context *ce;

        INIT_LIST_HEAD(&engines->link);

        engines->ctx = i915_gem_context_get(ctx);

        for_each_gem_engine(ce, engines, it) {
                int err;

                /* serialises with execbuf */
                set_bit(CONTEXT_CLOSED_BIT, &ce->flags);
                if (!intel_context_pin_if_active(ce))
                        continue;

                /* Wait until context is finally scheduled out and retired */
                err = i915_sw_fence_await_active(&engines->fence,
                                                 &ce->active,
                                                 I915_ACTIVE_AWAIT_BARRIER);
                intel_context_unpin(ce);
                if (err)
                        goto kill;
        }

        spin_lock_irq(&ctx->stale.lock);
        if (!i915_gem_context_is_closed(ctx))
                list_add_tail(&engines->link, &ctx->stale.engines);
        spin_unlock_irq(&ctx->stale.lock);

kill:
        if (list_empty(&engines->link)) /* raced, already closed */
                kill_engines(engines, true);

        i915_sw_fence_commit(&engines->fence);
}

static void set_closed_name(struct i915_gem_context *ctx)
{
        char *s;

        /* Replace '[]' with '<>' to indicate closed in debug prints */

        s = strrchr(ctx->name, '[');
        if (!s)
                return;

        *s = '<';

        s = strchr(s + 1, ']');
        if (s)
                *s = '>';
}

static void context_close(struct i915_gem_context *ctx)
{
        struct i915_address_space *vm;

        /* Flush any concurrent set_engines() */
        mutex_lock(&ctx->engines_mutex);
        engines_idle_release(ctx, rcu_replace_pointer(ctx->engines, NULL, 1));
        i915_gem_context_set_closed(ctx);
        mutex_unlock(&ctx->engines_mutex);

        mutex_lock(&ctx->mutex);

        set_closed_name(ctx);

        vm = i915_gem_context_vm(ctx);
        if (vm)
                i915_vm_close(vm);

        ctx->file_priv = ERR_PTR(-EBADF);

        /*
         * The LUT uses the VMA as a backpointer to unref the object,
         * so we need to clear the LUT before we close all the VMA (inside
         * the ppgtt).
         */
        lut_close(ctx);

        spin_lock(&ctx->i915->gem.contexts.lock);
        list_del(&ctx->link);
        spin_unlock(&ctx->i915->gem.contexts.lock);

        mutex_unlock(&ctx->mutex);

        /*
         * If the user has disabled hangchecking, we can not be sure that
         * the batches will ever complete after the context is closed,
         * keeping the context and all resources pinned forever. So in this
         * case we opt to forcibly kill off all remaining requests on
         * context close.
         */
        kill_context(ctx);

        i915_gem_context_put(ctx);
}

static int __context_set_persistence(struct i915_gem_context *ctx, bool state)
{
        if (i915_gem_context_is_persistent(ctx) == state)
                return 0;

        if (state) {
                /*
                 * Only contexts that are short-lived [that will expire or be
                 * reset] are allowed to survive past termination. We require
                 * hangcheck to ensure that the persistent requests are healthy.
                 */
                if (!ctx->i915->params.enable_hangcheck)
                        return -EINVAL;

                i915_gem_context_set_persistence(ctx);
        } else {
                /* To cancel a context we use "preempt-to-idle" */
                if (!(ctx->i915->caps.scheduler & I915_SCHEDULER_CAP_PREEMPTION))
                        return -ENODEV;

                /*
                 * If the cancel fails, we then need to reset, cleanly!
                 *
                 * If the per-engine reset fails, all hope is lost! We resort
                 * to a full GPU reset in that unlikely case, but realistically
                 * if the engine could not reset, the full reset does not fare
                 * much better. The damage has been done.
                 *
                 * However, if we cannot reset an engine by itself, we cannot
                 * cleanup a hanging persistent context without causing
                 * colateral damage, and we should not pretend we can by
                 * exposing the interface.
                 */
                if (!intel_has_reset_engine(&ctx->i915->gt))
                        return -ENODEV;

                i915_gem_context_clear_persistence(ctx);
        }

        return 0;
}

static inline struct i915_gem_engines *
__context_engines_await(const struct i915_gem_context *ctx,
                        bool *user_engines)
{
        struct i915_gem_engines *engines;

        rcu_read_lock();
        do {
                engines = rcu_dereference(ctx->engines);
                GEM_BUG_ON(!engines);

                if (user_engines)
                        *user_engines = i915_gem_context_user_engines(ctx);

                /* successful await => strong mb */
                if (unlikely(!i915_sw_fence_await(&engines->fence)))
                        continue;

                if (likely(engines == rcu_access_pointer(ctx->engines)))
                        break;

                i915_sw_fence_complete(&engines->fence);
        } while (1);
        rcu_read_unlock();

        return engines;
}

static void
context_apply_all(struct i915_gem_context *ctx,
                  void (*fn)(struct intel_context *ce, void *data),
                  void *data)
{
        struct i915_gem_engines_iter it;
        struct i915_gem_engines *e;
        struct intel_context *ce;

        e = __context_engines_await(ctx, NULL);
        for_each_gem_engine(ce, e, it)
                fn(ce, data);
        i915_sw_fence_complete(&e->fence);
}

static struct i915_gem_context *
i915_gem_create_context(struct drm_i915_private *i915,
                        const struct i915_gem_proto_context *pc)
{
        struct i915_gem_context *ctx;
        struct i915_address_space *vm = NULL;
        struct i915_gem_engines *e;
        int err;
        int i;

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

        kref_init(&ctx->ref);
        ctx->i915 = i915;
        ctx->sched = pc->sched;
        mutex_init(&ctx->mutex);
        INIT_LIST_HEAD(&ctx->link);

        spin_lock_init(&ctx->stale.lock);
        INIT_LIST_HEAD(&ctx->stale.engines);

        if (pc->vm) {
                vm = i915_vm_get(pc->vm);
        } else if (HAS_FULL_PPGTT(i915)) {
                struct i915_ppgtt *ppgtt;

                ppgtt = i915_ppgtt_create(&i915->gt);
                if (IS_ERR(ppgtt)) {
                        drm_dbg(&i915->drm, "PPGTT setup failed (%ld)\n",
                                PTR_ERR(ppgtt));
                        err = PTR_ERR(ppgtt);
                        goto err_ctx;
                }
                vm = &ppgtt->vm;
        }
        if (vm) {
                RCU_INIT_POINTER(ctx->vm, i915_vm_open(vm));

                /* i915_vm_open() takes a reference */
                i915_vm_put(vm);
        }

        mutex_init(&ctx->engines_mutex);
        if (pc->num_user_engines >= 0) {
                i915_gem_context_set_user_engines(ctx);
                e = user_engines(ctx, pc->num_user_engines, pc->user_engines);
        } else {
                i915_gem_context_clear_user_engines(ctx);
                e = default_engines(ctx, pc->legacy_rcs_sseu);
        }
        if (IS_ERR(e)) {
                err = PTR_ERR(e);
                goto err_vm;
        }
        RCU_INIT_POINTER(ctx->engines, e);

        INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);
        mutex_init(&ctx->lut_mutex);

        /* NB: Mark all slices as needing a remap so that when the context first
         * loads it will restore whatever remap state already exists. If there
         * is no remap info, it will be a NOP. */
        ctx->remap_slice = ALL_L3_SLICES(i915);

        ctx->user_flags = pc->user_flags;

        for (i = 0; i < ARRAY_SIZE(ctx->hang_timestamp); i++)
                ctx->hang_timestamp[i] = jiffies - CONTEXT_FAST_HANG_JIFFIES;

        if (pc->single_timeline) {
                err = drm_syncobj_create(&ctx->syncobj,
                                         DRM_SYNCOBJ_CREATE_SIGNALED,
                                         NULL);
                if (err)
                        goto err_engines;
        }

        trace_i915_context_create(ctx);

        return ctx;

err_engines:
        free_engines(e);
err_vm:
        if (ctx->vm)
                i915_vm_close(ctx->vm);
err_ctx:
        kfree(ctx);
        return ERR_PTR(err);
}

static void init_contexts(struct i915_gem_contexts *gc)
{
        spin_lock_init(&gc->lock);
        INIT_LIST_HEAD(&gc->list);
}

void i915_gem_init__contexts(struct drm_i915_private *i915)
{
        init_contexts(&i915->gem.contexts);
}

static void gem_context_register(struct i915_gem_context *ctx,
                                 struct drm_i915_file_private *fpriv,
                                 u32 id)
{
        struct drm_i915_private *i915 = ctx->i915;
        void *old;

        ctx->file_priv = fpriv;

        ctx->pid = get_task_pid(current, PIDTYPE_PID);
        snprintf(ctx->name, sizeof(ctx->name), "%s[%d]",
                 current->comm, pid_nr(ctx->pid));

        /* And finally expose ourselves to userspace via the idr */
        old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
        WARN_ON(old);

        spin_lock(&i915->gem.contexts.lock);
        list_add_tail(&ctx->link, &i915->gem.contexts.list);
        spin_unlock(&i915->gem.contexts.lock);
}

int i915_gem_context_open(struct drm_i915_private *i915,
                          struct drm_file *file)
{
        struct drm_i915_file_private *file_priv = file->driver_priv;
        struct i915_gem_proto_context *pc;
        struct i915_gem_context *ctx;
        int err;

        mutex_init(&file_priv->proto_context_lock);
        xa_init_flags(&file_priv->proto_context_xa, XA_FLAGS_ALLOC);

        /* 0 reserved for the default context */
        xa_init_flags(&file_priv->context_xa, XA_FLAGS_ALLOC1);

        /* 0 reserved for invalid/unassigned ppgtt */
        xa_init_flags(&file_priv->vm_xa, XA_FLAGS_ALLOC1);

        pc = proto_context_create(i915, 0);
        if (IS_ERR(pc)) {
                err = PTR_ERR(pc);
                goto err;
        }

        ctx = i915_gem_create_context(i915, pc);
        proto_context_close(pc);
        if (IS_ERR(ctx)) {
                err = PTR_ERR(ctx);
                goto err;
        }

        gem_context_register(ctx, file_priv, 0);

        return 0;

err:
        xa_destroy(&file_priv->vm_xa);
        xa_destroy(&file_priv->context_xa);
        xa_destroy(&file_priv->proto_context_xa);
        mutex_destroy(&file_priv->proto_context_lock);
        return err;
}

void i915_gem_context_close(struct drm_file *file)
{
        struct drm_i915_file_private *file_priv = file->driver_priv;
        struct i915_gem_proto_context *pc;
        struct i915_address_space *vm;
        struct i915_gem_context *ctx;
        unsigned long idx;

        xa_for_each(&file_priv->proto_context_xa, idx, pc)
                proto_context_close(pc);
        xa_destroy(&file_priv->proto_context_xa);
        mutex_destroy(&file_priv->proto_context_lock);

        xa_for_each(&file_priv->context_xa, idx, ctx)
                context_close(ctx);
        xa_destroy(&file_priv->context_xa);

        xa_for_each(&file_priv->vm_xa, idx, vm)
                i915_vm_put(vm);
        xa_destroy(&file_priv->vm_xa);
}

int i915_gem_vm_create_ioctl(struct drm_device *dev, void *data,
                             struct drm_file *file)
{
        struct drm_i915_private *i915 = to_i915(dev);
        struct drm_i915_gem_vm_control *args = data;
        struct drm_i915_file_private *file_priv = file->driver_priv;
        struct i915_ppgtt *ppgtt;
        u32 id;
        int err;

        if (!HAS_FULL_PPGTT(i915))
                return -ENODEV;

        if (args->flags)
                return -EINVAL;

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

        if (args->extensions) {
                err = i915_user_extensions(u64_to_user_ptr(args->extensions),
                                           NULL, 0,
                                           ppgtt);
                if (err)
                        goto err_put;
        }

        err = xa_alloc(&file_priv->vm_xa, &id, &ppgtt->vm,
                       xa_limit_32b, GFP_KERNEL);
        if (err)
                goto err_put;

        GEM_BUG_ON(id == 0); /* reserved for invalid/unassigned ppgtt */
        args->vm_id = id;
        return 0;

err_put:
        i915_vm_put(&ppgtt->vm);
        return err;
}

int i915_gem_vm_destroy_ioctl(struct drm_device *dev, void *data,
                              struct drm_file *file)
{
        struct drm_i915_file_private *file_priv = file->driver_priv;
        struct drm_i915_gem_vm_control *args = data;
        struct i915_address_space *vm;

        if (args->flags)
                return -EINVAL;

        if (args->extensions)
                return -EINVAL;

        vm = xa_erase(&file_priv->vm_xa, args->vm_id);
        if (!vm)
                return -ENOENT;

        i915_vm_put(vm);
        return 0;
}

static int get_ppgtt(struct drm_i915_file_private *file_priv,
                     struct i915_gem_context *ctx,
                     struct drm_i915_gem_context_param *args)
{
        struct i915_address_space *vm;
        int err;
        u32 id;

        if (!rcu_access_pointer(ctx->vm))
                return -ENODEV;

        rcu_read_lock();
        vm = context_get_vm_rcu(ctx);
        rcu_read_unlock();
        if (!vm)
                return -ENODEV;

        err = xa_alloc(&file_priv->vm_xa, &id, vm, xa_limit_32b, GFP_KERNEL);
        if (err)
                goto err_put;

        i915_vm_open(vm);

        GEM_BUG_ON(id == 0); /* reserved for invalid/unassigned ppgtt */
        args->value = id;
        args->size = 0;

err_put:
        i915_vm_put(vm);
        return err;
}

int
i915_gem_user_to_context_sseu(struct intel_gt *gt,
                              const struct drm_i915_gem_context_param_sseu *user,
                              struct intel_sseu *context)
{
        const struct sseu_dev_info *device = &gt->info.sseu;
        struct drm_i915_private *i915 = gt->i915;

        /* No zeros in any field. */
        if (!user->slice_mask || !user->subslice_mask ||
            !user->min_eus_per_subslice || !user->max_eus_per_subslice)
                return -EINVAL;

        /* Max > min. */
        if (user->max_eus_per_subslice < user->min_eus_per_subslice)
                return -EINVAL;

        /*
         * Some future proofing on the types since the uAPI is wider than the
         * current internal implementation.
         */
        if (overflows_type(user->slice_mask, context->slice_mask) ||
            overflows_type(user->subslice_mask, context->subslice_mask) ||
            overflows_type(user->min_eus_per_subslice,
                           context->min_eus_per_subslice) ||
            overflows_type(user->max_eus_per_subslice,
                           context->max_eus_per_subslice))
                return -EINVAL;

        /* Check validity against hardware. */
        if (user->slice_mask & ~device->slice_mask)
                return -EINVAL;

        if (user->subslice_mask & ~device->subslice_mask[0])
                return -EINVAL;

        if (user->max_eus_per_subslice > device->max_eus_per_subslice)
                return -EINVAL;

        context->slice_mask = user->slice_mask;
        context->subslice_mask = user->subslice_mask;
        context->min_eus_per_subslice = user->min_eus_per_subslice;
        context->max_eus_per_subslice = user->max_eus_per_subslice;

        /* Part specific restrictions. */
        if (GRAPHICS_VER(i915) == 11) {
                unsigned int hw_s = hweight8(device->slice_mask);
                unsigned int hw_ss_per_s = hweight8(device->subslice_mask[0]);
                unsigned int req_s = hweight8(context->slice_mask);
                unsigned int req_ss = hweight8(context->subslice_mask);

                /*
                 * Only full subslice enablement is possible if more than one
                 * slice is turned on.
                 */
                if (req_s > 1 && req_ss != hw_ss_per_s)
                        return -EINVAL;

                /*
                 * If more than four (SScount bitfield limit) subslices are
                 * requested then the number has to be even.
                 */
                if (req_ss > 4 && (req_ss & 1))
                        return -EINVAL;

                /*
                 * If only one slice is enabled and subslice count is below the
                 * device full enablement, it must be at most half of the all
                 * available subslices.
                 */
                if (req_s == 1 && req_ss < hw_ss_per_s &&
                    req_ss > (hw_ss_per_s / 2))
                        return -EINVAL;

                /* ABI restriction - VME use case only. */

                /* All slices or one slice only. */
                if (req_s != 1 && req_s != hw_s)
                        return -EINVAL;

                /*
                 * Half subslices or full enablement only when one slice is
                 * enabled.
                 */
                if (req_s == 1 &&
                    (req_ss != hw_ss_per_s && req_ss != (hw_ss_per_s / 2)))
                        return -EINVAL;

                /* No EU configuration changes. */
                if ((user->min_eus_per_subslice !=
                     device->max_eus_per_subslice) ||
                    (user->max_eus_per_subslice !=
                     device->max_eus_per_subslice))
                        return -EINVAL;
        }

        return 0;
}

static int set_sseu(struct i915_gem_context *ctx,
                    struct drm_i915_gem_context_param *args)
{
        struct drm_i915_private *i915 = ctx->i915;
        struct drm_i915_gem_context_param_sseu user_sseu;
        struct intel_context *ce;
        struct intel_sseu sseu;
        unsigned long lookup;
        int ret;

        if (args->size < sizeof(user_sseu))
                return -EINVAL;

        if (GRAPHICS_VER(i915) != 11)
                return -ENODEV;

        if (copy_from_user(&user_sseu, u64_to_user_ptr(args->value),
                           sizeof(user_sseu)))
                return -EFAULT;

        if (user_sseu.rsvd)
                return -EINVAL;

        if (user_sseu.flags & ~(I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX))
                return -EINVAL;

        lookup = 0;
        if (user_sseu.flags & I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX)
                lookup |= LOOKUP_USER_INDEX;

        ce = lookup_user_engine(ctx, lookup, &user_sseu.engine);
        if (IS_ERR(ce))
                return PTR_ERR(ce);

        /* Only render engine supports RPCS configuration. */
        if (ce->engine->class != RENDER_CLASS) {
                ret = -ENODEV;
                goto out_ce;
        }

        ret = i915_gem_user_to_context_sseu(ce->engine->gt, &user_sseu, &sseu);
        if (ret)
                goto out_ce;

        ret = intel_context_reconfigure_sseu(ce, sseu);
        if (ret)
                goto out_ce;

        args->size = sizeof(user_sseu);

out_ce:
        intel_context_put(ce);
        return ret;
}

static int
set_persistence(struct i915_gem_context *ctx,
                const struct drm_i915_gem_context_param *args)
{
        if (args->size)
                return -EINVAL;

        return __context_set_persistence(ctx, args->value);
}

static void __apply_priority(struct intel_context *ce, void *arg)
{
        struct i915_gem_context *ctx = arg;

        if (!intel_engine_has_timeslices(ce->engine))
                return;

        if (ctx->sched.priority >= I915_PRIORITY_NORMAL &&
            intel_engine_has_semaphores(ce->engine))
                intel_context_set_use_semaphores(ce);
        else
                intel_context_clear_use_semaphores(ce);
}

static int set_priority(struct i915_gem_context *ctx,
                        const struct drm_i915_gem_context_param *args)
{
        int err;

        err = validate_priority(ctx->i915, args);
        if (err)
                return err;

        ctx->sched.priority = args->value;
        context_apply_all(ctx, __apply_priority, ctx);

        return 0;
}

static int ctx_setparam(struct drm_i915_file_private *fpriv,
                        struct i915_gem_context *ctx,
                        struct drm_i915_gem_context_param *args)
{
        int ret = 0;

        switch (args->param) {
        case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
                if (args->size)
                        ret = -EINVAL;
                else if (args->value)
                        i915_gem_context_set_no_error_capture(ctx);
                else
                        i915_gem_context_clear_no_error_capture(ctx);
                break;

        case I915_CONTEXT_PARAM_BANNABLE:
                if (args->size)
                        ret = -EINVAL;
                else if (!capable(CAP_SYS_ADMIN) && !args->value)
                        ret = -EPERM;
                else if (args->value)
                        i915_gem_context_set_bannable(ctx);
                else
                        i915_gem_context_clear_bannable(ctx);
                break;

        case I915_CONTEXT_PARAM_RECOVERABLE:
                if (args->size)
                        ret = -EINVAL;
                else if (args->value)
                        i915_gem_context_set_recoverable(ctx);
                else
                        i915_gem_context_clear_recoverable(ctx);
                break;

        case I915_CONTEXT_PARAM_PRIORITY:
                ret = set_priority(ctx, args);
                break;

        case I915_CONTEXT_PARAM_SSEU:
                ret = set_sseu(ctx, args);
                break;

        case I915_CONTEXT_PARAM_PERSISTENCE:
                ret = set_persistence(ctx, args);
                break;

        case I915_CONTEXT_PARAM_NO_ZEROMAP:
        case I915_CONTEXT_PARAM_BAN_PERIOD:
        case I915_CONTEXT_PARAM_RINGSIZE:
        case I915_CONTEXT_PARAM_VM:
        case I915_CONTEXT_PARAM_ENGINES:
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

struct create_ext {
        struct i915_gem_proto_context *pc;
        struct drm_i915_file_private *fpriv;
};

static int create_setparam(struct i915_user_extension __user *ext, void *data)
{
        struct drm_i915_gem_context_create_ext_setparam local;
        const struct create_ext *arg = data;

        if (copy_from_user(&local, ext, sizeof(local)))
                return -EFAULT;

        if (local.param.ctx_id)
                return -EINVAL;

        return set_proto_ctx_param(arg->fpriv, arg->pc, &local.param);
}

static int invalid_ext(struct i915_user_extension __user *ext, void *data)
{
        return -EINVAL;
}

static const i915_user_extension_fn create_extensions[] = {
        [I915_CONTEXT_CREATE_EXT_SETPARAM] = create_setparam,
        [I915_CONTEXT_CREATE_EXT_CLONE] = invalid_ext,
};

static bool client_is_banned(struct drm_i915_file_private *file_priv)
{
        return atomic_read(&file_priv->ban_score) >= I915_CLIENT_SCORE_BANNED;
}

static inline struct i915_gem_context *
__context_lookup(struct drm_i915_file_private *file_priv, u32 id)
{
        struct i915_gem_context *ctx;

        rcu_read_lock();
        ctx = xa_load(&file_priv->context_xa, id);
        if (ctx && !kref_get_unless_zero(&ctx->ref))
                ctx = NULL;
        rcu_read_unlock();

        return ctx;
}

static struct i915_gem_context *
finalize_create_context_locked(struct drm_i915_file_private *file_priv,
                               struct i915_gem_proto_context *pc, u32 id)
{
        struct i915_gem_context *ctx;
        void *old;

        lockdep_assert_held(&file_priv->proto_context_lock);

        ctx = i915_gem_create_context(file_priv->dev_priv, pc);
        if (IS_ERR(ctx))
                return ctx;

        gem_context_register(ctx, file_priv, id);

        old = xa_erase(&file_priv->proto_context_xa, id);
        GEM_BUG_ON(old != pc);
        proto_context_close(pc);

        /* One for the xarray and one for the caller */
        return i915_gem_context_get(ctx);
}

struct i915_gem_context *
i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id)
{
        struct i915_gem_proto_context *pc;
        struct i915_gem_context *ctx;

        ctx = __context_lookup(file_priv, id);
        if (ctx)
                return ctx;

        mutex_lock(&file_priv->proto_context_lock);
        /* Try one more time under the lock */
        ctx = __context_lookup(file_priv, id);
        if (!ctx) {
                pc = xa_load(&file_priv->proto_context_xa, id);
                if (!pc)
                        ctx = ERR_PTR(-ENOENT);
                else
                        ctx = finalize_create_context_locked(file_priv, pc, id);
        }
        mutex_unlock(&file_priv->proto_context_lock);

        return ctx;
}

int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
                                  struct drm_file *file)
{
        struct drm_i915_private *i915 = to_i915(dev);
        struct drm_i915_gem_context_create_ext *args = data;
        struct create_ext ext_data;
        int ret;
        u32 id;

        if (!DRIVER_CAPS(i915)->has_logical_contexts)
                return -ENODEV;

        if (args->flags & I915_CONTEXT_CREATE_FLAGS_UNKNOWN)
                return -EINVAL;

        ret = intel_gt_terminally_wedged(&i915->gt);
        if (ret)
                return ret;

        ext_data.fpriv = file->driver_priv;
        if (client_is_banned(ext_data.fpriv)) {
                drm_dbg(&i915->drm,
                        "client %s[%d] banned from creating ctx\n",
                        current->comm, task_pid_nr(current));
                return -EIO;
        }

        ext_data.pc = proto_context_create(i915, args->flags);
        if (IS_ERR(ext_data.pc))
                return PTR_ERR(ext_data.pc);

        if (args->flags & I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS) {
                ret = i915_user_extensions(u64_to_user_ptr(args->extensions),
                                           create_extensions,
                                           ARRAY_SIZE(create_extensions),
                                           &ext_data);
                if (ret)
                        goto err_pc;
        }

        if (GRAPHICS_VER(i915) > 12) {
                struct i915_gem_context *ctx;

                /* Get ourselves a context ID */
                ret = xa_alloc(&ext_data.fpriv->context_xa, &id, NULL,
                               xa_limit_32b, GFP_KERNEL);
                if (ret)
                        goto err_pc;

                ctx = i915_gem_create_context(i915, ext_data.pc);
                if (IS_ERR(ctx)) {
                        ret = PTR_ERR(ctx);
                        goto err_pc;
                }

                proto_context_close(ext_data.pc);
                gem_context_register(ctx, ext_data.fpriv, id);
        } else {
                ret = proto_context_register(ext_data.fpriv, ext_data.pc, &id);
                if (ret < 0)
                        goto err_pc;
        }

        args->ctx_id = id;
        drm_dbg(&i915->drm, "HW context %d created\n", args->ctx_id);

        return 0;

err_pc:
        proto_context_close(ext_data.pc);
        return ret;
}

int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
                                   struct drm_file *file)
{
        struct drm_i915_gem_context_destroy *args = data;
        struct drm_i915_file_private *file_priv = file->driver_priv;
        struct i915_gem_proto_context *pc;
        struct i915_gem_context *ctx;

        if (args->pad != 0)
                return -EINVAL;

        if (!args->ctx_id)
                return -ENOENT;

        /* We need to hold the proto-context lock here to prevent races
         * with finalize_create_context_locked().
         */
        mutex_lock(&file_priv->proto_context_lock);
        ctx = xa_erase(&file_priv->context_xa, args->ctx_id);
        pc = xa_erase(&file_priv->proto_context_xa, args->ctx_id);
        mutex_unlock(&file_priv->proto_context_lock);

        if (!ctx && !pc)
                return -ENOENT;
        GEM_WARN_ON(ctx && pc);

        if (pc)
                proto_context_close(pc);

        if (ctx)
                context_close(ctx);

        return 0;
}

static int get_sseu(struct i915_gem_context *ctx,
                    struct drm_i915_gem_context_param *args)
{
        struct drm_i915_gem_context_param_sseu user_sseu;
        struct intel_context *ce;
        unsigned long lookup;
        int err;

        if (args->size == 0)
                goto out;
        else if (args->size < sizeof(user_sseu))
                return -EINVAL;

        if (copy_from_user(&user_sseu, u64_to_user_ptr(args->value),
                           sizeof(user_sseu)))
                return -EFAULT;

        if (user_sseu.rsvd)
                return -EINVAL;

        if (user_sseu.flags & ~(I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX))
                return -EINVAL;

        lookup = 0;
        if (user_sseu.flags & I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX)
                lookup |= LOOKUP_USER_INDEX;

        ce = lookup_user_engine(ctx, lookup, &user_sseu.engine);
        if (IS_ERR(ce))
                return PTR_ERR(ce);

        err = intel_context_lock_pinned(ce); /* serialises with set_sseu */
        if (err) {
                intel_context_put(ce);
                return err;
        }

        user_sseu.slice_mask = ce->sseu.slice_mask;
        user_sseu.subslice_mask = ce->sseu.subslice_mask;
        user_sseu.min_eus_per_subslice = ce->sseu.min_eus_per_subslice;
        user_sseu.max_eus_per_subslice = ce->sseu.max_eus_per_subslice;

        intel_context_unlock_pinned(ce);
        intel_context_put(ce);

        if (copy_to_user(u64_to_user_ptr(args->value), &user_sseu,
                         sizeof(user_sseu)))
                return -EFAULT;

out:
        args->size = sizeof(user_sseu);

        return 0;
}

int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
                                    struct drm_file *file)
{
        struct drm_i915_file_private *file_priv = file->driver_priv;
        struct drm_i915_gem_context_param *args = data;
        struct i915_gem_context *ctx;
        int ret = 0;

        ctx = i915_gem_context_lookup(file_priv, args->ctx_id);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);

        switch (args->param) {
        case I915_CONTEXT_PARAM_GTT_SIZE:
                args->size = 0;
                rcu_read_lock();
                if (rcu_access_pointer(ctx->vm))
                        args->value = rcu_dereference(ctx->vm)->total;
                else
                        args->value = to_i915(dev)->ggtt.vm.total;
                rcu_read_unlock();
                break;

        case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
                args->size = 0;
                args->value = i915_gem_context_no_error_capture(ctx);
                break;

        case I915_CONTEXT_PARAM_BANNABLE:
                args->size = 0;
                args->value = i915_gem_context_is_bannable(ctx);
                break;

        case I915_CONTEXT_PARAM_RECOVERABLE:
                args->size = 0;
                args->value = i915_gem_context_is_recoverable(ctx);
                break;

        case I915_CONTEXT_PARAM_PRIORITY:
                args->size = 0;
                args->value = ctx->sched.priority;
                break;

        case I915_CONTEXT_PARAM_SSEU:
                ret = get_sseu(ctx, args);
                break;

        case I915_CONTEXT_PARAM_VM:
                ret = get_ppgtt(file_priv, ctx, args);
                break;

        case I915_CONTEXT_PARAM_PERSISTENCE:
                args->size = 0;
                args->value = i915_gem_context_is_persistent(ctx);
                break;

        case I915_CONTEXT_PARAM_NO_ZEROMAP:
        case I915_CONTEXT_PARAM_BAN_PERIOD:
        case I915_CONTEXT_PARAM_ENGINES:
        case I915_CONTEXT_PARAM_RINGSIZE:
        default:
                ret = -EINVAL;
                break;
        }

        i915_gem_context_put(ctx);
        return ret;
}

int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
                                    struct drm_file *file)
{
        struct drm_i915_file_private *file_priv = file->driver_priv;
        struct drm_i915_gem_context_param *args = data;
        struct i915_gem_proto_context *pc;
        struct i915_gem_context *ctx;
        int ret = 0;

        mutex_lock(&file_priv->proto_context_lock);
        ctx = __context_lookup(file_priv, args->ctx_id);
        if (!ctx) {
                pc = xa_load(&file_priv->proto_context_xa, args->ctx_id);
                if (pc) {
                        /* Contexts should be finalized inside
                         * GEM_CONTEXT_CREATE starting with graphics
                         * version 13.
                         */
                        WARN_ON(GRAPHICS_VER(file_priv->dev_priv) > 12);
                        ret = set_proto_ctx_param(file_priv, pc, args);
                } else {
                        ret = -ENOENT;
                }
        }
        mutex_unlock(&file_priv->proto_context_lock);

        if (ctx) {
                ret = ctx_setparam(file_priv, ctx, args);
                i915_gem_context_put(ctx);
        }

        return ret;
}

int i915_gem_context_reset_stats_ioctl(struct drm_device *dev,
                                       void *data, struct drm_file *file)
{
        struct drm_i915_private *i915 = to_i915(dev);
        struct drm_i915_reset_stats *args = data;
        struct i915_gem_context *ctx;

        if (args->flags || args->pad)
                return -EINVAL;

        ctx = i915_gem_context_lookup(file->driver_priv, args->ctx_id);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);

        /*
         * We opt for unserialised reads here. This may result in tearing
         * in the extremely unlikely event of a GPU hang on this context
         * as we are querying them. If we need that extra layer of protection,
         * we should wrap the hangstats with a seqlock.
         */

        if (capable(CAP_SYS_ADMIN))
                args->reset_count = i915_reset_count(&i915->gpu_error);
        else
                args->reset_count = 0;

        args->batch_active = atomic_read(&ctx->guilty_count);
        args->batch_pending = atomic_read(&ctx->active_count);

        i915_gem_context_put(ctx);
        return 0;
}

/* GEM context-engines iterator: for_each_gem_engine() */
struct intel_context *
i915_gem_engines_iter_next(struct i915_gem_engines_iter *it)
{
        const struct i915_gem_engines *e = it->engines;
        struct intel_context *ctx;

        if (unlikely(!e))
                return NULL;

        do {
                if (it->idx >= e->num_engines)
                        return NULL;

                ctx = e->engines[it->idx++];
        } while (!ctx);

        return ctx;
}

#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/mock_context.c"
#include "selftests/i915_gem_context.c"
#endif

void i915_gem_context_module_exit(void)
{
        kmem_cache_destroy(slab_luts);
}

int __init i915_gem_context_module_init(void)
{
        slab_luts = KMEM_CACHE(i915_lut_handle, 0);
        if (!slab_luts)
                return -ENOMEM;

        return 0;
}