text: // SPDX-License-Identifier: GPL-2.0 OR MIT
  /**************************************************************************
   *
   * Copyright 2009-2015 VMware, Inc., Palo Alto, CA., USA
   *
   * 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, sub license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
   * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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.
   *
   **************************************************************************/
  
  #include <drm/ttm/ttm_placement.h>
  
  #include "vmwgfx_resource_priv.h"
  #include "vmwgfx_binding.h"
  #include "vmwgfx_drv.h"
  
  #define VMW_RES_EVICT_ERR_COUNT 10
  
  /**
   * vmw_resource_mob_attach - Mark a resource as attached to its backing mob
   * @res: The resource
   */
  void vmw_resource_mob_attach(struct vmw_resource *res)
  {
  	struct vmw_buffer_object *backup = res->backup;
  	struct rb_node **new = &backup->res_tree.rb_node, *parent = NULL;
  
  	dma_resv_assert_held(res->backup->base.base.resv);
  	res->used_prio = (res->res_dirty) ? res->func->dirty_prio :
  		res->func->prio;
  
  	while (*new) {
  		struct vmw_resource *this =
  			container_of(*new, struct vmw_resource, mob_node);
  
  		parent = *new;
  		new = (res->backup_offset < this->backup_offset) ?
  			&((*new)->rb_left) : &((*new)->rb_right);
  	}
  
  	rb_link_node(&res->mob_node, parent, new);
  	rb_insert_color(&res->mob_node, &backup->res_tree);
  
  	vmw_bo_prio_add(backup, res->used_prio);
  }
  
  /**
   * vmw_resource_mob_detach - Mark a resource as detached from its backing mob
   * @res: The resource
   */
  void vmw_resource_mob_detach(struct vmw_resource *res)
  {
  	struct vmw_buffer_object *backup = res->backup;
  
  	dma_resv_assert_held(backup->base.base.resv);
  	if (vmw_resource_mob_attached(res)) {
  		rb_erase(&res->mob_node, &backup->res_tree);
  		RB_CLEAR_NODE(&res->mob_node);
  		vmw_bo_prio_del(backup, res->used_prio);
  	}
  }
  
  struct vmw_resource *vmw_resource_reference(struct vmw_resource *res)
  {
  	kref_get(&res->kref);
  	return res;
  }
  
  struct vmw_resource *
  vmw_resource_reference_unless_doomed(struct vmw_resource *res)
  {
  	return kref_get_unless_zero(&res->kref) ? res : NULL;
  }
  
  /**
   * vmw_resource_release_id - release a resource id to the id manager.
   *
   * @res: Pointer to the resource.
   *
   * Release the resource id to the resource id manager and set it to -1
   */
  void vmw_resource_release_id(struct vmw_resource *res)
  {
  	struct vmw_private *dev_priv = res->dev_priv;
  	struct idr *idr = &dev_priv->res_idr[res->func->res_type];
  
  	spin_lock(&dev_priv->resource_lock);
  	if (res->id != -1)
  		idr_remove(idr, res->id);
  	res->id = -1;
  	spin_unlock(&dev_priv->resource_lock);
  }
  
  static void vmw_resource_release(struct kref *kref)
  {
  	struct vmw_resource *res =
  	    container_of(kref, struct vmw_resource, kref);
  	struct vmw_private *dev_priv = res->dev_priv;
  	int id;
  	struct idr *idr = &dev_priv->res_idr[res->func->res_type];
  
  	spin_lock(&dev_priv->resource_lock);
  	list_del_init(&res->lru_head);
  	spin_unlock(&dev_priv->resource_lock);
  	if (res->backup) {
  		struct ttm_buffer_object *bo = &res->backup->base;
  
  		ttm_bo_reserve(bo, false, false, NULL);
  		if (vmw_resource_mob_attached(res) &&
  		    res->func->unbind != NULL) {
  			struct ttm_validate_buffer val_buf;
  
  			val_buf.bo = bo;
  			val_buf.num_shared = 0;
  			res->func->unbind(res, false, &val_buf);
  		}
  		res->backup_dirty = false;
  		vmw_resource_mob_detach(res);
  		if (res->dirty)
  			res->func->dirty_free(res);
  		if (res->coherent)
  			vmw_bo_dirty_release(res->backup);
  		ttm_bo_unreserve(bo);
  		vmw_bo_unreference(&res->backup);
  	}
  
  	if (likely(res->hw_destroy != NULL)) {
  		mutex_lock(&dev_priv->binding_mutex);
  		vmw_binding_res_list_kill(&res->binding_head);
  		mutex_unlock(&dev_priv->binding_mutex);
  		res->hw_destroy(res);
  	}
  
  	id = res->id;
  	if (res->res_free != NULL)
  		res->res_free(res);
  	else
  		kfree(res);
  
  	spin_lock(&dev_priv->resource_lock);
  	if (id != -1)
  		idr_remove(idr, id);
  	spin_unlock(&dev_priv->resource_lock);
  }
  
  void vmw_resource_unreference(struct vmw_resource **p_res)
  {
  	struct vmw_resource *res = *p_res;
  
  	*p_res = NULL;
  	kref_put(&res->kref, vmw_resource_release);
  }
  
  
  /**
   * vmw_resource_alloc_id - release a resource id to the id manager.
   *
   * @res: Pointer to the resource.
   *
   * Allocate the lowest free resource from the resource manager, and set
   * @res->id to that id. Returns 0 on success and -ENOMEM on failure.
   */
  int vmw_resource_alloc_id(struct vmw_resource *res)
  {
  	struct vmw_private *dev_priv = res->dev_priv;
  	int ret;
  	struct idr *idr = &dev_priv->res_idr[res->func->res_type];
  
  	BUG_ON(res->id != -1);
  
  	idr_preload(GFP_KERNEL);
  	spin_lock(&dev_priv->resource_lock);
  
  	ret = idr_alloc(idr, res, 1, 0, GFP_NOWAIT);
  	if (ret >= 0)
  		res->id = ret;
  
  	spin_unlock(&dev_priv->resource_lock);
  	idr_preload_end();
  	return ret < 0 ? ret : 0;
  }
  
  /**
   * vmw_resource_init - initialize a struct vmw_resource
   *
   * @dev_priv:       Pointer to a device private struct.
   * @res:            The struct vmw_resource to initialize.
   * @obj_type:       Resource object type.
   * @delay_id:       Boolean whether to defer device id allocation until
   *                  the first validation.
   * @res_free:       Resource destructor.
   * @func:           Resource function table.
   */
  int vmw_resource_init(struct vmw_private *dev_priv, struct vmw_resource *res,
  		      bool delay_id,
  		      void (*res_free) (struct vmw_resource *res),
  		      const struct vmw_res_func *func)
  {
  	kref_init(&res->kref);
  	res->hw_destroy = NULL;
  	res->res_free = res_free;
  	res->dev_priv = dev_priv;
  	res->func = func;
  	RB_CLEAR_NODE(&res->mob_node);
  	INIT_LIST_HEAD(&res->lru_head);
  	INIT_LIST_HEAD(&res->binding_head);
  	res->id = -1;
  	res->backup = NULL;
  	res->backup_offset = 0;
  	res->backup_dirty = false;
  	res->res_dirty = false;
  	res->coherent = false;
  	res->used_prio = 3;
  	res->dirty = NULL;
  	if (delay_id)
  		return 0;
  	else
  		return vmw_resource_alloc_id(res);
  }
  
  
  /**
   * vmw_user_resource_lookup_handle - lookup a struct resource from a
   * TTM user-space handle and perform basic type checks
   *
   * @dev_priv:     Pointer to a device private struct
   * @tfile:        Pointer to a struct ttm_object_file identifying the caller
   * @handle:       The TTM user-space handle
   * @converter:    Pointer to an object describing the resource type
   * @p_res:        On successful return the location pointed to will contain
   *                a pointer to a refcounted struct vmw_resource.
   *
   * If the handle can't be found or is associated with an incorrect resource
   * type, -EINVAL will be returned.
   */
  int vmw_user_resource_lookup_handle(struct vmw_private *dev_priv,
  				    struct ttm_object_file *tfile,
  				    uint32_t handle,
  				    const struct vmw_user_resource_conv
  				    *converter,
  				    struct vmw_resource **p_res)
  {
  	struct ttm_base_object *base;
  	struct vmw_resource *res;
  	int ret = -EINVAL;
  
  	base = ttm_base_object_lookup(tfile, handle);
  	if (unlikely(base == NULL))
  		return -EINVAL;
  
  	if (unlikely(ttm_base_object_type(base) != converter->object_type))
  		goto out_bad_resource;
  
  	res = converter->base_obj_to_res(base);
  	kref_get(&res->kref);
  
  	*p_res = res;
  	ret = 0;
  
  out_bad_resource:
  	ttm_base_object_unref(&base);
  
  	return ret;
  }
  
  /**
   * vmw_user_resource_lookup_handle - lookup a struct resource from a
   * TTM user-space handle and perform basic type checks
   *
   * @dev_priv:     Pointer to a device private struct
   * @tfile:        Pointer to a struct ttm_object_file identifying the caller
   * @handle:       The TTM user-space handle
   * @converter:    Pointer to an object describing the resource type
   * @p_res:        On successful return the location pointed to will contain
   *                a pointer to a refcounted struct vmw_resource.
   *
   * If the handle can't be found or is associated with an incorrect resource
   * type, -EINVAL will be returned.
   */
  struct vmw_resource *
  vmw_user_resource_noref_lookup_handle(struct vmw_private *dev_priv,
  				      struct ttm_object_file *tfile,
  				      uint32_t handle,
  				      const struct vmw_user_resource_conv
  				      *converter)
  {
  	struct ttm_base_object *base;
  
  	base = ttm_base_object_noref_lookup(tfile, handle);
  	if (!base)
  		return ERR_PTR(-ESRCH);
  
  	if (unlikely(ttm_base_object_type(base) != converter->object_type)) {
  		ttm_base_object_noref_release();
  		return ERR_PTR(-EINVAL);
  	}
  
  	return converter->base_obj_to_res(base);
  }
  
  /**
   * Helper function that looks either a surface or bo.
   *
   * The pointer this pointed at by out_surf and out_buf needs to be null.
   */
  int vmw_user_lookup_handle(struct vmw_private *dev_priv,
  			   struct ttm_object_file *tfile,
  			   uint32_t handle,
  			   struct vmw_surface **out_surf,
  			   struct vmw_buffer_object **out_buf)
  {
  	struct vmw_resource *res;
  	int ret;
  
  	BUG_ON(*out_surf || *out_buf);
  
  	ret = vmw_user_resource_lookup_handle(dev_priv, tfile, handle,
  					      user_surface_converter,
  					      &res);
  	if (!ret) {
  		*out_surf = vmw_res_to_srf(res);
  		return 0;
  	}
  
  	*out_surf = NULL;
  	ret = vmw_user_bo_lookup(tfile, handle, out_buf, NULL);
  	return ret;
  }
  
  /**
   * vmw_resource_buf_alloc - Allocate a backup buffer for a resource.
   *
   * @res:            The resource for which to allocate a backup buffer.
   * @interruptible:  Whether any sleeps during allocation should be
   *                  performed while interruptible.
   */
  static int vmw_resource_buf_alloc(struct vmw_resource *res,
  				  bool interruptible)
  {
  	unsigned long size =
  		(res->backup_size + PAGE_SIZE - 1) & PAGE_MASK;
  	struct vmw_buffer_object *backup;
  	int ret;
  
  	if (likely(res->backup)) {
  		BUG_ON(res->backup->base.base.size < size);
  		return 0;
  	}
  
  	backup = kzalloc(sizeof(*backup), GFP_KERNEL);
  	if (unlikely(!backup))
  		return -ENOMEM;
  
  	ret = vmw_bo_init(res->dev_priv, backup, res->backup_size,
  			      res->func->backup_placement,
  			      interruptible, false,
  			      &vmw_bo_bo_free);
  	if (unlikely(ret != 0))
  		goto out_no_bo;
  
  	res->backup = backup;
  
  out_no_bo:
  	return ret;
  }
  
  /**
   * vmw_resource_do_validate - Make a resource up-to-date and visible
   *                            to the device.
   *
   * @res:            The resource to make visible to the device.
   * @val_buf:        Information about a buffer possibly
   *                  containing backup data if a bind operation is needed.
   *
   * On hardware resource shortage, this function returns -EBUSY and
   * should be retried once resources have been freed up.
   */
  static int vmw_resource_do_validate(struct vmw_resource *res,
  				    struct ttm_validate_buffer *val_buf,
  				    bool dirtying)
  {
  	int ret = 0;
  	const struct vmw_res_func *func = res->func;
  
  	if (unlikely(res->id == -1)) {
  		ret = func->create(res);
  		if (unlikely(ret != 0))
  			return ret;
  	}
  
  	if (func->bind &&
  	    ((func->needs_backup && !vmw_resource_mob_attached(res) &&
  	      val_buf->bo != NULL) ||
  	     (!func->needs_backup && val_buf->bo != NULL))) {
  		ret = func->bind(res, val_buf);
  		if (unlikely(ret != 0))
  			goto out_bind_failed;
  		if (func->needs_backup)
  			vmw_resource_mob_attach(res);
  	}
  
  	/*
  	 * Handle the case where the backup mob is marked coherent but
  	 * the resource isn't.
  	 */
  	if (func->dirty_alloc && vmw_resource_mob_attached(res) &&
  	    !res->coherent) {
  		if (res->backup->dirty && !res->dirty) {
  			ret = func->dirty_alloc(res);
  			if (ret)
  				return ret;
  		} else if (!res->backup->dirty && res->dirty) {
  			func->dirty_free(res);
  		}
  	}
  
  	/*
  	 * Transfer the dirty regions to the resource and update
  	 * the resource.
  	 */
  	if (res->dirty) {
  		if (dirtying && !res->res_dirty) {
  			pgoff_t start = res->backup_offset >> PAGE_SHIFT;
  			pgoff_t end = __KERNEL_DIV_ROUND_UP
  				(res->backup_offset + res->backup_size,
  				 PAGE_SIZE);
  
  			vmw_bo_dirty_unmap(res->backup, start, end);
  		}
  
  		vmw_bo_dirty_transfer_to_res(res);
  		return func->dirty_sync(res);
  	}
  
  	return 0;
  
  out_bind_failed:
  	func->destroy(res);
  
  	return ret;
  }
  
  /**
   * vmw_resource_unreserve - Unreserve a resource previously reserved for
   * command submission.
   *
   * @res:               Pointer to the struct vmw_resource to unreserve.
   * @dirty_set:         Change dirty status of the resource.
   * @dirty:             When changing dirty status indicates the new status.
   * @switch_backup:     Backup buffer has been switched.
   * @new_backup:        Pointer to new backup buffer if command submission
   *                     switched. May be NULL.
   * @new_backup_offset: New backup offset if @switch_backup is true.
   *
   * Currently unreserving a resource means putting it back on the device's
   * resource lru list, so that it can be evicted if necessary.
   */
  void vmw_resource_unreserve(struct vmw_resource *res,
  			    bool dirty_set,
  			    bool dirty,
  			    bool switch_backup,
  			    struct vmw_buffer_object *new_backup,
  			    unsigned long new_backup_offset)
  {
  	struct vmw_private *dev_priv = res->dev_priv;
  
  	if (!list_empty(&res->lru_head))
  		return;
  
  	if (switch_backup && new_backup != res->backup) {
  		if (res->backup) {
  			vmw_resource_mob_detach(res);
  			if (res->coherent)
  				vmw_bo_dirty_release(res->backup);
  			vmw_bo_unreference(&res->backup);
  		}
  
  		if (new_backup) {
  			res->backup = vmw_bo_reference(new_backup);
  
  			/*
  			 * The validation code should already have added a
  			 * dirty tracker here.
  			 */
  			WARN_ON(res->coherent && !new_backup->dirty);
  
  			vmw_resource_mob_attach(res);
  		} else {
  			res->backup = NULL;
  		}
  	} else if (switch_backup && res->coherent) {
  		vmw_bo_dirty_release(res->backup);
  	}
  
  	if (switch_backup)
  		res->backup_offset = new_backup_offset;
  
  	if (dirty_set)
  		res->res_dirty = dirty;
  
  	if (!res->func->may_evict || res->id == -1 || res->pin_count)
  		return;
  
  	spin_lock(&dev_priv->resource_lock);
  	list_add_tail(&res->lru_head,
  		      &res->dev_priv->res_lru[res->func->res_type]);
  	spin_unlock(&dev_priv->resource_lock);
  }
  
  /**
   * vmw_resource_check_buffer - Check whether a backup buffer is needed
   *                             for a resource and in that case, allocate
   *                             one, reserve and validate it.
   *
   * @ticket:         The ww aqcquire context to use, or NULL if trylocking.
   * @res:            The resource for which to allocate a backup buffer.
   * @interruptible:  Whether any sleeps during allocation should be
   *                  performed while interruptible.
   * @val_buf:        On successful return contains data about the
   *                  reserved and validated backup buffer.
   */
  static int
  vmw_resource_check_buffer(struct ww_acquire_ctx *ticket,
  			  struct vmw_resource *res,
  			  bool interruptible,
  			  struct ttm_validate_buffer *val_buf)
  {
  	struct ttm_operation_ctx ctx = { true, false };
  	struct list_head val_list;
  	bool backup_dirty = false;
  	int ret;
  
  	if (unlikely(res->backup == NULL)) {
  		ret = vmw_resource_buf_alloc(res, interruptible);
  		if (unlikely(ret != 0))
  			return ret;
  	}
  
  	INIT_LIST_HEAD(&val_list);
  	ttm_bo_get(&res->backup->base);
  	val_buf->bo = &res->backup->base;
  	val_buf->num_shared = 0;
  	list_add_tail(&val_buf->head, &val_list);
  	ret = ttm_eu_reserve_buffers(ticket, &val_list, interruptible, NULL);
  	if (unlikely(ret != 0))
  		goto out_no_reserve;
  
  	if (res->func->needs_backup && !vmw_resource_mob_attached(res))
  		return 0;
  
  	backup_dirty = res->backup_dirty;
  	ret = ttm_bo_validate(&res->backup->base,
  			      res->func->backup_placement,
  			      &ctx);
  
  	if (unlikely(ret != 0))
  		goto out_no_validate;
  
  	return 0;
  
  out_no_validate:
  	ttm_eu_backoff_reservation(ticket, &val_list);
  out_no_reserve:
  	ttm_bo_put(val_buf->bo);
  	val_buf->bo = NULL;
  	if (backup_dirty)
  		vmw_bo_unreference(&res->backup);
  
  	return ret;
  }
  
  /**
   * vmw_resource_reserve - Reserve a resource for command submission
   *
   * @res:            The resource to reserve.
   *
   * This function takes the resource off the LRU list and make sure
   * a backup buffer is present for guest-backed resources. However,
   * the buffer may not be bound to the resource at this point.
   *
   */
  int vmw_resource_reserve(struct vmw_resource *res, bool interruptible,
  			 bool no_backup)
  {
  	struct vmw_private *dev_priv = res->dev_priv;
  	int ret;
  
  	spin_lock(&dev_priv->resource_lock);
  	list_del_init(&res->lru_head);
  	spin_unlock(&dev_priv->resource_lock);
  
  	if (res->func->needs_backup && res->backup == NULL &&
  	    !no_backup) {
  		ret = vmw_resource_buf_alloc(res, interruptible);
  		if (unlikely(ret != 0)) {
  			DRM_ERROR("Failed to allocate a backup buffer "
  				  "of size %lu. bytes\n",
  				  (unsigned long) res->backup_size);
  			return ret;
  		}
  	}
  
  	return 0;
  }
  
  /**
   * vmw_resource_backoff_reservation - Unreserve and unreference a
   *                                    backup buffer
   *.
   * @ticket:         The ww acquire ctx used for reservation.
   * @val_buf:        Backup buffer information.
   */
  static void
  vmw_resource_backoff_reservation(struct ww_acquire_ctx *ticket,
  				 struct ttm_validate_buffer *val_buf)
  {
  	struct list_head val_list;
  
  	if (likely(val_buf->bo == NULL))
  		return;
  
  	INIT_LIST_HEAD(&val_list);
  	list_add_tail(&val_buf->head, &val_list);
  	ttm_eu_backoff_reservation(ticket, &val_list);
  	ttm_bo_put(val_buf->bo);
  	val_buf->bo = NULL;
  }
  
  /**
   * vmw_resource_do_evict - Evict a resource, and transfer its data
   *                         to a backup buffer.
   *
   * @ticket:         The ww acquire ticket to use, or NULL if trylocking.
   * @res:            The resource to evict.
   * @interruptible:  Whether to wait interruptible.
   */
  static int vmw_resource_do_evict(struct ww_acquire_ctx *ticket,
  				 struct vmw_resource *res, bool interruptible)
  {
  	struct ttm_validate_buffer val_buf;
  	const struct vmw_res_func *func = res->func;
  	int ret;
  
  	BUG_ON(!func->may_evict);
  
  	val_buf.bo = NULL;
  	val_buf.num_shared = 0;
  	ret = vmw_resource_check_buffer(ticket, res, interruptible, &val_buf);
  	if (unlikely(ret != 0))
  		return ret;
  
  	if (unlikely(func->unbind != NULL &&
  		     (!func->needs_backup || vmw_resource_mob_attached(res)))) {
  		ret = func->unbind(res, res->res_dirty, &val_buf);
  		if (unlikely(ret != 0))
  			goto out_no_unbind;
  		vmw_resource_mob_detach(res);
  	}
  	ret = func->destroy(res);
  	res->backup_dirty = true;
  	res->res_dirty = false;
  out_no_unbind:
  	vmw_resource_backoff_reservation(ticket, &val_buf);
  
  	return ret;
  }
  
  
  /**
   * vmw_resource_validate - Make a resource up-to-date and visible
   *                         to the device.
   * @res: The resource to make visible to the device.
   * @intr: Perform waits interruptible if possible.
   * @dirtying: Pending GPU operation will dirty the resource
   *
   * On succesful return, any backup DMA buffer pointed to by @res->backup will
   * be reserved and validated.
   * On hardware resource shortage, this function will repeatedly evict
   * resources of the same type until the validation succeeds.
   *
   * Return: Zero on success, -ERESTARTSYS if interrupted, negative error code
   * on failure.
   */
  int vmw_resource_validate(struct vmw_resource *res, bool intr,
  			  bool dirtying)
  {
  	int ret;
  	struct vmw_resource *evict_res;
  	struct vmw_private *dev_priv = res->dev_priv;
  	struct list_head *lru_list = &dev_priv->res_lru[res->func->res_type];
  	struct ttm_validate_buffer val_buf;
  	unsigned err_count = 0;
  
  	if (!res->func->create)
  		return 0;
  
  	val_buf.bo = NULL;
  	val_buf.num_shared = 0;
  	if (res->backup)
  		val_buf.bo = &res->backup->base;
  	do {
  		ret = vmw_resource_do_validate(res, &val_buf, dirtying);
  		if (likely(ret != -EBUSY))
  			break;
  
  		spin_lock(&dev_priv->resource_lock);
  		if (list_empty(lru_list) || !res->func->may_evict) {
  			DRM_ERROR("Out of device device resources "
  				  "for %s.\n", res->func->type_name);
  			ret = -EBUSY;
  			spin_unlock(&dev_priv->resource_lock);
  			break;
  		}
  
  		evict_res = vmw_resource_reference
  			(list_first_entry(lru_list, struct vmw_resource,
  					  lru_head));
  		list_del_init(&evict_res->lru_head);
  
  		spin_unlock(&dev_priv->resource_lock);
  
  		/* Trylock backup buffers with a NULL ticket. */
  		ret = vmw_resource_do_evict(NULL, evict_res, intr);
  		if (unlikely(ret != 0)) {
  			spin_lock(&dev_priv->resource_lock);
  			list_add_tail(&evict_res->lru_head, lru_list);
  			spin_unlock(&dev_priv->resource_lock);
  			if (ret == -ERESTARTSYS ||
  			    ++err_count > VMW_RES_EVICT_ERR_COUNT) {
  				vmw_resource_unreference(&evict_res);
  				goto out_no_validate;
  			}
  		}
  
  		vmw_resource_unreference(&evict_res);
  	} while (1);
  
  	if (unlikely(ret != 0))
  		goto out_no_validate;
  	else if (!res->func->needs_backup && res->backup) {
  		WARN_ON_ONCE(vmw_resource_mob_attached(res));
  		vmw_bo_unreference(&res->backup);
  	}
  
  	return 0;
  
  out_no_validate:
  	return ret;
  }
  
  
  /**
   * vmw_resource_unbind_list
   *
   * @vbo: Pointer to the current backing MOB.
   *
   * Evicts the Guest Backed hardware resource if the backup
   * buffer is being moved out of MOB memory.
   * Note that this function will not race with the resource
   * validation code, since resource validation and eviction
   * both require the backup buffer to be reserved.
   */
  void vmw_resource_unbind_list(struct vmw_buffer_object *vbo)
  {
  	struct ttm_validate_buffer val_buf = {
  		.bo = &vbo->base,
  		.num_shared = 0
  	};
  
  	dma_resv_assert_held(vbo->base.base.resv);
  	while (!RB_EMPTY_ROOT(&vbo->res_tree)) {
  		struct rb_node *node = vbo->res_tree.rb_node;
  		struct vmw_resource *res =
  			container_of(node, struct vmw_resource, mob_node);
  
  		if (!WARN_ON_ONCE(!res->func->unbind))
  			(void) res->func->unbind(res, res->res_dirty, &val_buf);
  
  		res->backup_dirty = true;
  		res->res_dirty = false;
  		vmw_resource_mob_detach(res);
  	}
  
  	(void) ttm_bo_wait(&vbo->base, false, false);
  }
  
  
  /**
   * vmw_query_readback_all - Read back cached query states
   *
   * @dx_query_mob: Buffer containing the DX query MOB
   *
   * Read back cached states from the device if they exist.  This function
   * assumings binding_mutex is held.
   */
  int vmw_query_readback_all(struct vmw_buffer_object *dx_query_mob)
  {
  	struct vmw_resource *dx_query_ctx;
  	struct vmw_private *dev_priv;
  	struct {
  		SVGA3dCmdHeader header;
  		SVGA3dCmdDXReadbackAllQuery body;
  	} *cmd;
  
  
  	/* No query bound, so do nothing */
  	if (!dx_query_mob || !dx_query_mob->dx_query_ctx)
  		return 0;
  
  	dx_query_ctx = dx_query_mob->dx_query_ctx;
  	dev_priv     = dx_query_ctx->dev_priv;
  
  	cmd = VMW_CMD_CTX_RESERVE(dev_priv, sizeof(*cmd), dx_query_ctx->id);
  	if (unlikely(cmd == NULL))
  		return -ENOMEM;
  
  	cmd->header.id   = SVGA_3D_CMD_DX_READBACK_ALL_QUERY;
  	cmd->header.size = sizeof(cmd->body);
  	cmd->body.cid    = dx_query_ctx->id;
  
  	vmw_cmd_commit(dev_priv, sizeof(*cmd));
  
  	/* Triggers a rebind the next time affected context is bound */
  	dx_query_mob->dx_query_ctx = NULL;
  
  	return 0;
  }
  
  
  
  /**
   * vmw_query_move_notify - Read back cached query states
   *
   * @bo: The TTM buffer object about to move.
   * @mem: The memory region @bo is moving to.
   *
   * Called before the query MOB is swapped out to read back cached query
   * states from the device.
   */
  void vmw_query_move_notify(struct ttm_buffer_object *bo,
  			   struct ttm_resource *mem)
  {
  	struct vmw_buffer_object *dx_query_mob;
  	struct ttm_bo_device *bdev = bo->bdev;
  	struct vmw_private *dev_priv;
  
  
  	dev_priv = container_of(bdev, struct vmw_private, bdev);
  
  	mutex_lock(&dev_priv->binding_mutex);
  
  	dx_query_mob = container_of(bo, struct vmw_buffer_object, base);
  	if (!dx_query_mob || !dx_query_mob->dx_query_ctx) {
  		mutex_unlock(&dev_priv->binding_mutex);
  		return;
  	}
  
  	/* If BO is being moved from MOB to system memory */
  	if (mem->mem_type == TTM_PL_SYSTEM && bo->mem.mem_type == VMW_PL_MOB) {
  		struct vmw_fence_obj *fence;
  
  		(void) vmw_query_readback_all(dx_query_mob);
  		mutex_unlock(&dev_priv->binding_mutex);
  
  		/* Create a fence and attach the BO to it */
  		(void) vmw_execbuf_fence_commands(NULL, dev_priv, &fence, NULL);
  		vmw_bo_fence_single(bo, fence);
  
  		if (fence != NULL)
  			vmw_fence_obj_unreference(&fence);
  
  		(void) ttm_bo_wait(bo, false, false);
  	} else
  		mutex_unlock(&dev_priv->binding_mutex);
  
  }
  
  /**
   * vmw_resource_needs_backup - Return whether a resource needs a backup buffer.
   *
   * @res:            The resource being queried.
   */
  bool vmw_resource_needs_backup(const struct vmw_resource *res)
  {
  	return res->func->needs_backup;
  }
  
  /**
   * vmw_resource_evict_type - Evict all resources of a specific type
   *
   * @dev_priv:       Pointer to a device private struct
   * @type:           The resource type to evict
   *
   * To avoid thrashing starvation or as part of the hibernation sequence,
   * try to evict all evictable resources of a specific type.
   */
  static void vmw_resource_evict_type(struct vmw_private *dev_priv,
  				    enum vmw_res_type type)
  {
  	struct list_head *lru_list = &dev_priv->res_lru[type];
  	struct vmw_resource *evict_res;
  	unsigned err_count = 0;
  	int ret;
  	struct ww_acquire_ctx ticket;
  
  	do {
  		spin_lock(&dev_priv->resource_lock);
  
  		if (list_empty(lru_list))
  			goto out_unlock;
  
  		evict_res = vmw_resource_reference(
  			list_first_entry(lru_list, struct vmw_resource,
  					 lru_head));
  		list_del_init(&evict_res->lru_head);
  		spin_unlock(&dev_priv->resource_lock);
  
  		/* Wait lock backup buffers with a ticket. */
  		ret = vmw_resource_do_evict(&ticket, evict_res, false);
  		if (unlikely(ret != 0)) {
  			spin_lock(&dev_priv->resource_lock);
  			list_add_tail(&evict_res->lru_head, lru_list);
  			spin_unlock(&dev_priv->resource_lock);
  			if (++err_count > VMW_RES_EVICT_ERR_COUNT) {
  				vmw_resource_unreference(&evict_res);
  				return;
  			}
  		}
  
  		vmw_resource_unreference(&evict_res);
  	} while (1);
  
  out_unlock:
  	spin_unlock(&dev_priv->resource_lock);
  }
  
  /**
   * vmw_resource_evict_all - Evict all evictable resources
   *
   * @dev_priv:       Pointer to a device private struct
   *
   * To avoid thrashing starvation or as part of the hibernation sequence,
   * evict all evictable resources. In particular this means that all
   * guest-backed resources that are registered with the device are
   * evicted and the OTable becomes clean.
   */
  void vmw_resource_evict_all(struct vmw_private *dev_priv)
  {
  	enum vmw_res_type type;
  
  	mutex_lock(&dev_priv->cmdbuf_mutex);
  
  	for (type = 0; type < vmw_res_max; ++type)
  		vmw_resource_evict_type(dev_priv, type);
  
  	mutex_unlock(&dev_priv->cmdbuf_mutex);
  }
  
  /**
   * vmw_resource_pin - Add a pin reference on a resource
   *
   * @res: The resource to add a pin reference on
   *
   * This function adds a pin reference, and if needed validates the resource.
   * Having a pin reference means that the resource can never be evicted, and
   * its id will never change as long as there is a pin reference.
   * This function returns 0 on success and a negative error code on failure.
   */
  int vmw_resource_pin(struct vmw_resource *res, bool interruptible)
  {
  	struct ttm_operation_ctx ctx = { interruptible, false };
  	struct vmw_private *dev_priv = res->dev_priv;
  	int ret;
  
  	ttm_write_lock(&dev_priv->reservation_sem, interruptible);
  	mutex_lock(&dev_priv->cmdbuf_mutex);
  	ret = vmw_resource_reserve(res, interruptible, false);
  	if (ret)
  		goto out_no_reserve;
  
  	if (res->pin_count == 0) {
  		struct vmw_buffer_object *vbo = NULL;
  
  		if (res->backup) {
  			vbo = res->backup;
  
  			ttm_bo_reserve(&vbo->base, interruptible, false, NULL);
  			if (!vbo->base.pin_count) {
  				ret = ttm_bo_validate
  					(&vbo->base,
  					 res->func->backup_placement,
  					 &ctx);
  				if (ret) {
  					ttm_bo_unreserve(&vbo->base);
  					goto out_no_validate;
  				}
  			}
  
  			/* Do we really need to pin the MOB as well? */
  			vmw_bo_pin_reserved(vbo, true);
  		}
  		ret = vmw_resource_validate(res, interruptible, true);
  		if (vbo)
  			ttm_bo_unreserve(&vbo->base);
  		if (ret)
  			goto out_no_validate;
  	}
  	res->pin_count++;
  
  out_no_validate:
  	vmw_resource_unreserve(res, false, false, false, NULL, 0UL);
  out_no_reserve:
  	mutex_unlock(&dev_priv->cmdbuf_mutex);
  	ttm_write_unlock(&dev_priv->reservation_sem);
  
  	return ret;
  }
  
  /**
   * vmw_resource_unpin - Remove a pin reference from a resource
   *
   * @res: The resource to remove a pin reference from
   *
   * Having a pin reference means that the resource can never be evicted, and
   * its id will never change as long as there is a pin reference.
   */
  void vmw_resource_unpin(struct vmw_resource *res)
  {
  	struct vmw_private *dev_priv = res->dev_priv;
  	int ret;
  
  	(void) ttm_read_lock(&dev_priv->reservation_sem, false);
  	mutex_lock(&dev_priv->cmdbuf_mutex);
  
  	ret = vmw_resource_reserve(res, false, true);
  	WARN_ON(ret);
  
  	WARN_ON(res->pin_count == 0);
  	if (--res->pin_count == 0 && res->backup) {
  		struct vmw_buffer_object *vbo = res->backup;
  
  		(void) ttm_bo_reserve(&vbo->base, false, false, NULL);
  		vmw_bo_pin_reserved(vbo, false);
  		ttm_bo_unreserve(&vbo->base);
  	}
  
  	vmw_resource_unreserve(res, false, false, false, NULL, 0UL);
  
  	mutex_unlock(&dev_priv->cmdbuf_mutex);
  	ttm_read_unlock(&dev_priv->reservation_sem);
  }
  
  /**
   * vmw_res_type - Return the resource type
   *
   * @res: Pointer to the resource
   */
  enum vmw_res_type vmw_res_type(const struct vmw_resource *res)
  {
  	return res->func->res_type;
  }
  
  /**
   * vmw_resource_update_dirty - Update a resource's dirty tracker with a
   * sequential range of touched backing store memory.
   * @res: The resource.
   * @start: The first page touched.
   * @end: The last page touched + 1.
   */
  void vmw_resource_dirty_update(struct vmw_resource *res, pgoff_t start,
  			       pgoff_t end)
  {
  	if (res->dirty)
  		res->func->dirty_range_add(res, start << PAGE_SHIFT,
  					   end << PAGE_SHIFT);
  }
  
  /**
   * vmw_resources_clean - Clean resources intersecting a mob range
   * @vbo: The mob buffer object
   * @start: The mob page offset starting the range
   * @end: The mob page offset ending the range
   * @num_prefault: Returns how many pages including the first have been
   * cleaned and are ok to prefault
   */
  int vmw_resources_clean(struct vmw_buffer_object *vbo, pgoff_t start,
  			pgoff_t end, pgoff_t *num_prefault)
  {
  	struct rb_node *cur = vbo->res_tree.rb_node;
  	struct vmw_resource *found = NULL;
  	unsigned long res_start = start << PAGE_SHIFT;
  	unsigned long res_end = end << PAGE_SHIFT;
  	unsigned long last_cleaned = 0;
  
  	/*
  	 * Find the resource with lowest backup_offset that intersects the
  	 * range.
  	 */
  	while (cur) {
  		struct vmw_resource *cur_res =
  			container_of(cur, struct vmw_resource, mob_node);
  
  		if (cur_res->backup_offset >= res_end) {
  			cur = cur->rb_left;
  		} else if (cur_res->backup_offset + cur_res->backup_size <=
  			   res_start) {
  			cur = cur->rb_right;
  		} else {
  			found = cur_res;
  			cur = cur->rb_left;
  			/* Continue to look for resources with lower offsets */
  		}
  	}
  
  	/*
  	 * In order of increasing backup_offset, clean dirty resorces
  	 * intersecting the range.
  	 */
  	while (found) {
  		if (found->res_dirty) {
  			int ret;
  
  			if (!found->func->clean)
  				return -EINVAL;
  
  			ret = found->func->clean(found);
  			if (ret)
  				return ret;
  
  			found->res_dirty = false;
  		}
  		last_cleaned = found->backup_offset + found->backup_size;
  		cur = rb_next(&found->mob_node);
  		if (!cur)
  			break;
  
  		found = container_of(cur, struct vmw_resource, mob_node);
  		if (found->backup_offset >= res_end)
  			break;
  	}
  
  	/*
  	 * Set number of pages allowed prefaulting and fence the buffer object
  	 */
  	*num_prefault = 1;
  	if (last_cleaned > res_start) {
  		struct ttm_buffer_object *bo = &vbo->base;
  
  		*num_prefault = __KERNEL_DIV_ROUND_UP(last_cleaned - res_start,
  						      PAGE_SIZE);
  		vmw_bo_fence_single(bo, NULL);
  		if (bo->moving)
  			dma_fence_put(bo->moving);
  		bo->moving = dma_fence_get
  			(dma_resv_get_excl(bo->base.resv));
  	}
  
  	return 0;
  }
  