drivers/gpu/drm/virtio/virtgpu_ttm.c - linux - Git at Google

 /*
  * Copyright (C) 2015 Red Hat, Inc.
  * All Rights Reserved.
  *
  * Authors:
  *    Dave Airlie
  *    Alon Levy
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) 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_bo_api.h>
 #include <drm/ttm/ttm_bo_driver.h>
 #include <drm/ttm/ttm_placement.h>
 #include <drm/ttm/ttm_page_alloc.h>
 #include <drm/ttm/ttm_module.h>
 #include <drm/drmP.h>
 #include <drm/drm.h>
 #include <drm/virtgpu_drm.h>
 #include "virtgpu_drv.h"

 #include <linux/delay.h>

 #define DRM_FILE_PAGE_OFFSET (0x100000000ULL >> PAGE_SHIFT)

 static struct
 virtio_gpu_device *virtio_gpu_get_vgdev(struct ttm_bo_device *bdev)
 {
 	struct virtio_gpu_mman *mman;
 	struct virtio_gpu_device *vgdev;

 	mman = container_of(bdev, struct virtio_gpu_mman, bdev);
 	vgdev = container_of(mman, struct virtio_gpu_device, mman);
 	return vgdev;
 }

 static int virtio_gpu_ttm_mem_global_init(struct drm_global_reference *ref)
 {
 	return ttm_mem_global_init(ref->object);
 }

 static void virtio_gpu_ttm_mem_global_release(struct drm_global_reference *ref)
 {
 	ttm_mem_global_release(ref->object);
 }

 static int virtio_gpu_ttm_global_init(struct virtio_gpu_device *vgdev)
 {
 	struct drm_global_reference *global_ref;
 	int r;

 	vgdev->mman.mem_global_referenced = false;
 	global_ref = &vgdev->mman.mem_global_ref;
 	global_ref->global_type = DRM_GLOBAL_TTM_MEM;
 	global_ref->size = sizeof(struct ttm_mem_global);
 	global_ref->init = &virtio_gpu_ttm_mem_global_init;
 	global_ref->release = &virtio_gpu_ttm_mem_global_release;

 	r = drm_global_item_ref(global_ref);
 	if (r != 0) {
 		DRM_ERROR("Failed setting up TTM memory accounting "
 			  "subsystem.\n");
 		return r;
 	}

 	vgdev->mman.bo_global_ref.mem_glob =
 		vgdev->mman.mem_global_ref.object;
 	global_ref = &vgdev->mman.bo_global_ref.ref;
 	global_ref->global_type = DRM_GLOBAL_TTM_BO;
 	global_ref->size = sizeof(struct ttm_bo_global);
 	global_ref->init = &ttm_bo_global_init;
 	global_ref->release = &ttm_bo_global_release;
 	r = drm_global_item_ref(global_ref);
 	if (r != 0) {
 		DRM_ERROR("Failed setting up TTM BO subsystem.\n");
 		drm_global_item_unref(&vgdev->mman.mem_global_ref);
 		return r;
 	}

 	vgdev->mman.mem_global_referenced = true;
 	return 0;
 }

 static void virtio_gpu_ttm_global_fini(struct virtio_gpu_device *vgdev)
 {
 	if (vgdev->mman.mem_global_referenced) {
 		drm_global_item_unref(&vgdev->mman.bo_global_ref.ref);
 		drm_global_item_unref(&vgdev->mman.mem_global_ref);
 		vgdev->mman.mem_global_referenced = false;
 	}
 }

 int virtio_gpu_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	struct drm_file *file_priv;
 	struct virtio_gpu_device *vgdev;
 	int r;

 	file_priv = filp->private_data;
 	vgdev = file_priv->minor->dev->dev_private;
 	if (vgdev == NULL) {
 		DRM_ERROR(
 		 "filp->private_data->minor->dev->dev_private == NULL\n");
 		return -EINVAL;
 	}
 	r = ttm_bo_mmap(filp, vma, &vgdev->mman.bdev);

 	return r;
 }

 static int virtio_gpu_invalidate_caches(struct ttm_bo_device *bdev,
 					uint32_t flags)
 {
 	return 0;
 }

 static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man,
 			       struct ttm_buffer_object *bo,
 			       const struct ttm_place *place,
 			       struct ttm_mem_reg *mem)
 {
 	mem->mm_node = (void *)1;
 	return 0;
 }

 static void ttm_bo_man_put_node(struct ttm_mem_type_manager *man,
 				struct ttm_mem_reg *mem)
 {
 	mem->mm_node = (void *)NULL;
 }

 static int ttm_bo_man_init(struct ttm_mem_type_manager *man,
 			   unsigned long p_size)
 {
 	return 0;
 }

 static int ttm_bo_man_takedown(struct ttm_mem_type_manager *man)
 {
 	return 0;
 }

 static void ttm_bo_man_debug(struct ttm_mem_type_manager *man,
 			     struct drm_printer *printer)
 {
 }

 static const struct ttm_mem_type_manager_func virtio_gpu_bo_manager_func = {
 	.init = ttm_bo_man_init,
 	.takedown = ttm_bo_man_takedown,
 	.get_node = ttm_bo_man_get_node,
 	.put_node = ttm_bo_man_put_node,
 	.debug = ttm_bo_man_debug
 };

 static int virtio_gpu_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
 				    struct ttm_mem_type_manager *man)
 {
 	struct virtio_gpu_device *vgdev;

 	vgdev = virtio_gpu_get_vgdev(bdev);

 	switch (type) {
 	case TTM_PL_SYSTEM:
 		/* System memory */
 		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
 		man->available_caching = TTM_PL_MASK_CACHING;
 		man->default_caching = TTM_PL_FLAG_CACHED;
 		break;
 	case TTM_PL_TT:
 		man->func = &virtio_gpu_bo_manager_func;
 		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
 		man->available_caching = TTM_PL_MASK_CACHING;
 		man->default_caching = TTM_PL_FLAG_CACHED;
 		break;
 	default:
 		DRM_ERROR("Unsupported memory type %u\n", (unsigned int)type);
 		return -EINVAL;
 	}
 	return 0;
 }

 static void virtio_gpu_evict_flags(struct ttm_buffer_object *bo,
 				struct ttm_placement *placement)
 {
 	static const struct ttm_place placements = {
 		.fpfn  = 0,
 		.lpfn  = 0,
 		.flags = TTM_PL_MASK_CACHING | TTM_PL_FLAG_SYSTEM,
 	};

 	placement->placement = &placements;
 	placement->busy_placement = &placements;
 	placement->num_placement = 1;
 	placement->num_busy_placement = 1;
 }

 static int virtio_gpu_verify_access(struct ttm_buffer_object *bo,
 				    struct file *filp)
 {
 	return 0;
 }

 static int virtio_gpu_ttm_io_mem_reserve(struct ttm_bo_device *bdev,
 					 struct ttm_mem_reg *mem)
 {
 	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];

 	mem->bus.addr = NULL;
 	mem->bus.offset = 0;
 	mem->bus.size = mem->num_pages << PAGE_SHIFT;
 	mem->bus.base = 0;
 	mem->bus.is_iomem = false;
 	if (!(man->flags & TTM_MEMTYPE_FLAG_MAPPABLE))
 		return -EINVAL;
 	switch (mem->mem_type) {
 	case TTM_PL_SYSTEM:
 	case TTM_PL_TT:
 		/* system memory */
 		return 0;
 	default:
 		return -EINVAL;
 	}
 	return 0;
 }

 static void virtio_gpu_ttm_io_mem_free(struct ttm_bo_device *bdev,
 				       struct ttm_mem_reg *mem)
 {
 }

 /*
  * TTM backend functions.
  */
 struct virtio_gpu_ttm_tt {
 	struct ttm_dma_tt		ttm;
 	struct virtio_gpu_device	*vgdev;
 	u64				offset;
 };

 static int virtio_gpu_ttm_backend_bind(struct ttm_tt *ttm,
 				       struct ttm_mem_reg *bo_mem)
 {
 	struct virtio_gpu_ttm_tt *gtt = (void *)ttm;

 	gtt->offset = (unsigned long)(bo_mem->start << PAGE_SHIFT);
 	if (!ttm->num_pages)
 		WARN(1, "nothing to bind %lu pages for mreg %p back %p!\n",
 		     ttm->num_pages, bo_mem, ttm);

 	/* Not implemented */
 	return 0;
 }

 static int virtio_gpu_ttm_backend_unbind(struct ttm_tt *ttm)
 {
 	/* Not implemented */
 	return 0;
 }

 static void virtio_gpu_ttm_backend_destroy(struct ttm_tt *ttm)
 {
 	struct virtio_gpu_ttm_tt *gtt = (void *)ttm;

 	ttm_dma_tt_fini(&gtt->ttm);
 	kfree(gtt);
 }

 static struct ttm_backend_func virtio_gpu_backend_func = {
 	.bind = &virtio_gpu_ttm_backend_bind,
 	.unbind = &virtio_gpu_ttm_backend_unbind,
 	.destroy = &virtio_gpu_ttm_backend_destroy,
 };

 static struct ttm_tt *virtio_gpu_ttm_tt_create(struct ttm_buffer_object *bo,
 					       uint32_t page_flags)
 {
 	struct virtio_gpu_device *vgdev;
 	struct virtio_gpu_ttm_tt *gtt;

 	vgdev = virtio_gpu_get_vgdev(bo->bdev);
 	gtt = kzalloc(sizeof(struct virtio_gpu_ttm_tt), GFP_KERNEL);
 	if (gtt == NULL)
 		return NULL;
 	gtt->ttm.ttm.func = &virtio_gpu_backend_func;
 	gtt->vgdev = vgdev;
 	if (ttm_dma_tt_init(&gtt->ttm, bo, page_flags)) {
 		kfree(gtt);
 		return NULL;
 	}
 	return &gtt->ttm.ttm;
 }

 static void virtio_gpu_move_null(struct ttm_buffer_object *bo,
 				 struct ttm_mem_reg *new_mem)
 {
 	struct ttm_mem_reg *old_mem = &bo->mem;

 	BUG_ON(old_mem->mm_node != NULL);
 	*old_mem = *new_mem;
 	new_mem->mm_node = NULL;
 }

 static int virtio_gpu_bo_move(struct ttm_buffer_object *bo, bool evict,
 			      struct ttm_operation_ctx *ctx,
 			      struct ttm_mem_reg *new_mem)
 {
 	int ret;

 	ret = ttm_bo_wait(bo, ctx->interruptible, ctx->no_wait_gpu);
 	if (ret)
 		return ret;

 	virtio_gpu_move_null(bo, new_mem);
 	return 0;
 }

 static void virtio_gpu_bo_move_notify(struct ttm_buffer_object *tbo,
 				      bool evict,
 				      struct ttm_mem_reg *new_mem)
 {
 	struct virtio_gpu_object *bo;
 	struct virtio_gpu_device *vgdev;

 	bo = container_of(tbo, struct virtio_gpu_object, tbo);
 	vgdev = (struct virtio_gpu_device *)bo->gem_base.dev->dev_private;

 	if (!new_mem || (new_mem->placement & TTM_PL_FLAG_SYSTEM)) {
 		if (bo->hw_res_handle)
 			virtio_gpu_object_detach(vgdev, bo);

 	} else if (new_mem->placement & TTM_PL_FLAG_TT) {
 		if (bo->hw_res_handle) {
 			virtio_gpu_object_attach(vgdev, bo, bo->hw_res_handle,
 						 NULL);
 		}
 	}
 }

 static void virtio_gpu_bo_swap_notify(struct ttm_buffer_object *tbo)
 {
 	struct virtio_gpu_object *bo;
 	struct virtio_gpu_device *vgdev;

 	bo = container_of(tbo, struct virtio_gpu_object, tbo);
 	vgdev = (struct virtio_gpu_device *)bo->gem_base.dev->dev_private;

 	if (bo->pages)
 		virtio_gpu_object_free_sg_table(bo);
 }

 static struct ttm_bo_driver virtio_gpu_bo_driver = {
 	.ttm_tt_create = &virtio_gpu_ttm_tt_create,
 	.invalidate_caches = &virtio_gpu_invalidate_caches,
 	.init_mem_type = &virtio_gpu_init_mem_type,
 	.eviction_valuable = ttm_bo_eviction_valuable,
 	.evict_flags = &virtio_gpu_evict_flags,
 	.move = &virtio_gpu_bo_move,
 	.verify_access = &virtio_gpu_verify_access,
 	.io_mem_reserve = &virtio_gpu_ttm_io_mem_reserve,
 	.io_mem_free = &virtio_gpu_ttm_io_mem_free,
 	.move_notify = &virtio_gpu_bo_move_notify,
 	.swap_notify = &virtio_gpu_bo_swap_notify,
 };

 int virtio_gpu_ttm_init(struct virtio_gpu_device *vgdev)
 {
 	int r;

 	r = virtio_gpu_ttm_global_init(vgdev);
 	if (r)
 		return r;
 	/* No others user of address space so set it to 0 */
 	r = ttm_bo_device_init(&vgdev->mman.bdev,
 			       vgdev->mman.bo_global_ref.ref.object,
 			       &virtio_gpu_bo_driver,
 			       vgdev->ddev->anon_inode->i_mapping,
 			       DRM_FILE_PAGE_OFFSET, 0);
 	if (r) {
 		DRM_ERROR("failed initializing buffer object driver(%d).\n", r);
 		goto err_dev_init;
 	}

 	r = ttm_bo_init_mm(&vgdev->mman.bdev, TTM_PL_TT, 0);
 	if (r) {
 		DRM_ERROR("Failed initializing GTT heap.\n");
 		goto err_mm_init;
 	}
 	return 0;

 err_mm_init:
 	ttm_bo_device_release(&vgdev->mman.bdev);
 err_dev_init:
 	virtio_gpu_ttm_global_fini(vgdev);
 	return r;
 }

 void virtio_gpu_ttm_fini(struct virtio_gpu_device *vgdev)
 {
 	ttm_bo_device_release(&vgdev->mman.bdev);
 	virtio_gpu_ttm_global_fini(vgdev);
 	DRM_INFO("virtio_gpu: ttm finalized\n");
 }
	/*
	* Copyright (C) 2015 Red Hat, Inc.
	* All Rights Reserved.
	*
	* Authors:
	* Dave Airlie
	* Alon Levy
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) 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_bo_api.h>
	#include <drm/ttm/ttm_bo_driver.h>
	#include <drm/ttm/ttm_placement.h>
	#include <drm/ttm/ttm_page_alloc.h>
	#include <drm/ttm/ttm_module.h>
	#include <drm/drmP.h>
	#include <drm/drm.h>
	#include <drm/virtgpu_drm.h>
	#include "virtgpu_drv.h"

	#include <linux/delay.h>

	#define DRM_FILE_PAGE_OFFSET (0x100000000ULL >> PAGE_SHIFT)

	static struct
	virtio_gpu_device virtio_gpu_get_vgdev(struct ttm_bo_device bdev)
	{
	struct virtio_gpu_mman *mman;
	struct virtio_gpu_device *vgdev;

	mman = container_of(bdev, struct virtio_gpu_mman, bdev);
	vgdev = container_of(mman, struct virtio_gpu_device, mman);
	return vgdev;
	}

	static int virtio_gpu_ttm_mem_global_init(struct drm_global_reference *ref)
	{
	return ttm_mem_global_init(ref->object);
	}

	static void virtio_gpu_ttm_mem_global_release(struct drm_global_reference *ref)
	{
	ttm_mem_global_release(ref->object);
	}

	static int virtio_gpu_ttm_global_init(struct virtio_gpu_device *vgdev)
	{
	struct drm_global_reference *global_ref;
	int r;

	vgdev->mman.mem_global_referenced = false;
	global_ref = &vgdev->mman.mem_global_ref;
	global_ref->global_type = DRM_GLOBAL_TTM_MEM;
	global_ref->size = sizeof(struct ttm_mem_global);
	global_ref->init = &virtio_gpu_ttm_mem_global_init;
	global_ref->release = &virtio_gpu_ttm_mem_global_release;

	r = drm_global_item_ref(global_ref);
	if (r != 0) {
	DRM_ERROR("Failed setting up TTM memory accounting "
	"subsystem.\n");
	return r;
	}

	vgdev->mman.bo_global_ref.mem_glob =
	vgdev->mman.mem_global_ref.object;
	global_ref = &vgdev->mman.bo_global_ref.ref;
	global_ref->global_type = DRM_GLOBAL_TTM_BO;
	global_ref->size = sizeof(struct ttm_bo_global);
	global_ref->init = &ttm_bo_global_init;
	global_ref->release = &ttm_bo_global_release;
	r = drm_global_item_ref(global_ref);
	if (r != 0) {
	DRM_ERROR("Failed setting up TTM BO subsystem.\n");
	drm_global_item_unref(&vgdev->mman.mem_global_ref);
	return r;
	}

	vgdev->mman.mem_global_referenced = true;
	return 0;
	}

	static void virtio_gpu_ttm_global_fini(struct virtio_gpu_device *vgdev)
	{
	if (vgdev->mman.mem_global_referenced) {
	drm_global_item_unref(&vgdev->mman.bo_global_ref.ref);
	drm_global_item_unref(&vgdev->mman.mem_global_ref);
	vgdev->mman.mem_global_referenced = false;
	}
	}

	int virtio_gpu_mmap(struct file filp, struct vm_area_struct vma)
	{
	struct drm_file *file_priv;
	struct virtio_gpu_device *vgdev;
	int r;

	file_priv = filp->private_data;
	vgdev = file_priv->minor->dev->dev_private;
	if (vgdev == NULL) {
	DRM_ERROR(
	"filp->private_data->minor->dev->dev_private == NULL\n");
	return -EINVAL;
	}
	r = ttm_bo_mmap(filp, vma, &vgdev->mman.bdev);

	return r;
	}

	static int virtio_gpu_invalidate_caches(struct ttm_bo_device *bdev,
	uint32_t flags)
	{
	return 0;
	}

	static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man,
	struct ttm_buffer_object *bo,
	const struct ttm_place *place,
	struct ttm_mem_reg *mem)
	{
	mem->mm_node = (void *)1;
	return 0;
	}

	static void ttm_bo_man_put_node(struct ttm_mem_type_manager *man,
	struct ttm_mem_reg *mem)
	{
	mem->mm_node = (void *)NULL;
	}

	static int ttm_bo_man_init(struct ttm_mem_type_manager *man,
	unsigned long p_size)
	{
	return 0;
	}

	static int ttm_bo_man_takedown(struct ttm_mem_type_manager *man)
	{
	return 0;
	}

	static void ttm_bo_man_debug(struct ttm_mem_type_manager *man,
	struct drm_printer *printer)
	{
	}

	static const struct ttm_mem_type_manager_func virtio_gpu_bo_manager_func = {
	.init = ttm_bo_man_init,
	.takedown = ttm_bo_man_takedown,
	.get_node = ttm_bo_man_get_node,
	.put_node = ttm_bo_man_put_node,
	.debug = ttm_bo_man_debug
	};

	static int virtio_gpu_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
	struct ttm_mem_type_manager *man)
	{
	struct virtio_gpu_device *vgdev;

	vgdev = virtio_gpu_get_vgdev(bdev);

	switch (type) {
	case TTM_PL_SYSTEM:
	/* System memory */
	man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
	man->available_caching = TTM_PL_MASK_CACHING;
	man->default_caching = TTM_PL_FLAG_CACHED;
	break;
	case TTM_PL_TT:
	man->func = &virtio_gpu_bo_manager_func;
	man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
	man->available_caching = TTM_PL_MASK_CACHING;
	man->default_caching = TTM_PL_FLAG_CACHED;
	break;
	default:
	DRM_ERROR("Unsupported memory type %u\n", (unsigned int)type);
	return -EINVAL;
	}
	return 0;
	}

	static void virtio_gpu_evict_flags(struct ttm_buffer_object *bo,
	struct ttm_placement *placement)
	{
	static const struct ttm_place placements = {
	.fpfn = 0,
	.lpfn = 0,
	.flags = TTM_PL_MASK_CACHING \| TTM_PL_FLAG_SYSTEM,
	};

	placement->placement = &placements;
	placement->busy_placement = &placements;
	placement->num_placement = 1;
	placement->num_busy_placement = 1;
	}

	static int virtio_gpu_verify_access(struct ttm_buffer_object *bo,
	struct file *filp)
	{
	return 0;
	}

	static int virtio_gpu_ttm_io_mem_reserve(struct ttm_bo_device *bdev,
	struct ttm_mem_reg *mem)
	{
	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];

	mem->bus.addr = NULL;
	mem->bus.offset = 0;
	mem->bus.size = mem->num_pages << PAGE_SHIFT;
	mem->bus.base = 0;
	mem->bus.is_iomem = false;
	if (!(man->flags & TTM_MEMTYPE_FLAG_MAPPABLE))
	return -EINVAL;
	switch (mem->mem_type) {
	case TTM_PL_SYSTEM:
	case TTM_PL_TT:
	/* system memory */
	return 0;
	default:
	return -EINVAL;
	}
	return 0;
	}

	static void virtio_gpu_ttm_io_mem_free(struct ttm_bo_device *bdev,
	struct ttm_mem_reg *mem)
	{
	}

	/*
	* TTM backend functions.
	*/
	struct virtio_gpu_ttm_tt {
	struct ttm_dma_tt ttm;
	struct virtio_gpu_device *vgdev;
	u64 offset;
	};

	static int virtio_gpu_ttm_backend_bind(struct ttm_tt *ttm,
	struct ttm_mem_reg *bo_mem)
	{
	struct virtio_gpu_ttm_tt gtt = (void )ttm;

	gtt->offset = (unsigned long)(bo_mem->start << PAGE_SHIFT);
	if (!ttm->num_pages)
	WARN(1, "nothing to bind %lu pages for mreg %p back %p!\n",
	ttm->num_pages, bo_mem, ttm);

	/* Not implemented */
	return 0;
	}

	static int virtio_gpu_ttm_backend_unbind(struct ttm_tt *ttm)
	{
	/* Not implemented */
	return 0;
	}

	static void virtio_gpu_ttm_backend_destroy(struct ttm_tt *ttm)
	{
	struct virtio_gpu_ttm_tt gtt = (void )ttm;

	ttm_dma_tt_fini(&gtt->ttm);
	kfree(gtt);
	}

	static struct ttm_backend_func virtio_gpu_backend_func = {
	.bind = &virtio_gpu_ttm_backend_bind,
	.unbind = &virtio_gpu_ttm_backend_unbind,
	.destroy = &virtio_gpu_ttm_backend_destroy,
	};

	static struct ttm_tt virtio_gpu_ttm_tt_create(struct ttm_buffer_object bo,
	uint32_t page_flags)
	{
	struct virtio_gpu_device *vgdev;
	struct virtio_gpu_ttm_tt *gtt;

	vgdev = virtio_gpu_get_vgdev(bo->bdev);
	gtt = kzalloc(sizeof(struct virtio_gpu_ttm_tt), GFP_KERNEL);
	if (gtt == NULL)
	return NULL;
	gtt->ttm.ttm.func = &virtio_gpu_backend_func;
	gtt->vgdev = vgdev;
	if (ttm_dma_tt_init(&gtt->ttm, bo, page_flags)) {
	kfree(gtt);
	return NULL;
	}
	return &gtt->ttm.ttm;
	}

	static void virtio_gpu_move_null(struct ttm_buffer_object *bo,
	struct ttm_mem_reg *new_mem)
	{
	struct ttm_mem_reg *old_mem = &bo->mem;

	BUG_ON(old_mem->mm_node != NULL);
	old_mem = new_mem;
	new_mem->mm_node = NULL;
	}

	static int virtio_gpu_bo_move(struct ttm_buffer_object *bo, bool evict,
	struct ttm_operation_ctx *ctx,
	struct ttm_mem_reg *new_mem)
	{
	int ret;

	ret = ttm_bo_wait(bo, ctx->interruptible, ctx->no_wait_gpu);
	if (ret)
	return ret;

	virtio_gpu_move_null(bo, new_mem);
	return 0;
	}

	static void virtio_gpu_bo_move_notify(struct ttm_buffer_object *tbo,
	bool evict,
	struct ttm_mem_reg *new_mem)
	{
	struct virtio_gpu_object *bo;
	struct virtio_gpu_device *vgdev;

	bo = container_of(tbo, struct virtio_gpu_object, tbo);
	vgdev = (struct virtio_gpu_device *)bo->gem_base.dev->dev_private;

	if (!new_mem \|\| (new_mem->placement & TTM_PL_FLAG_SYSTEM)) {
	if (bo->hw_res_handle)
	virtio_gpu_object_detach(vgdev, bo);

	} else if (new_mem->placement & TTM_PL_FLAG_TT) {
	if (bo->hw_res_handle) {
	virtio_gpu_object_attach(vgdev, bo, bo->hw_res_handle,
	NULL);
	}
	}
	}

	static void virtio_gpu_bo_swap_notify(struct ttm_buffer_object *tbo)
	{
	struct virtio_gpu_object *bo;
	struct virtio_gpu_device *vgdev;

	bo = container_of(tbo, struct virtio_gpu_object, tbo);
	vgdev = (struct virtio_gpu_device *)bo->gem_base.dev->dev_private;

	if (bo->pages)
	virtio_gpu_object_free_sg_table(bo);
	}

	static struct ttm_bo_driver virtio_gpu_bo_driver = {
	.ttm_tt_create = &virtio_gpu_ttm_tt_create,
	.invalidate_caches = &virtio_gpu_invalidate_caches,
	.init_mem_type = &virtio_gpu_init_mem_type,
	.eviction_valuable = ttm_bo_eviction_valuable,
	.evict_flags = &virtio_gpu_evict_flags,
	.move = &virtio_gpu_bo_move,
	.verify_access = &virtio_gpu_verify_access,
	.io_mem_reserve = &virtio_gpu_ttm_io_mem_reserve,
	.io_mem_free = &virtio_gpu_ttm_io_mem_free,
	.move_notify = &virtio_gpu_bo_move_notify,
	.swap_notify = &virtio_gpu_bo_swap_notify,
	};

	int virtio_gpu_ttm_init(struct virtio_gpu_device *vgdev)
	{
	int r;

	r = virtio_gpu_ttm_global_init(vgdev);
	if (r)
	return r;
	/* No others user of address space so set it to 0 */
	r = ttm_bo_device_init(&vgdev->mman.bdev,
	vgdev->mman.bo_global_ref.ref.object,
	&virtio_gpu_bo_driver,
	vgdev->ddev->anon_inode->i_mapping,
	DRM_FILE_PAGE_OFFSET, 0);
	if (r) {
	DRM_ERROR("failed initializing buffer object driver(%d).\n", r);
	goto err_dev_init;
	}

	r = ttm_bo_init_mm(&vgdev->mman.bdev, TTM_PL_TT, 0);
	if (r) {
	DRM_ERROR("Failed initializing GTT heap.\n");
	goto err_mm_init;
	}
	return 0;

	err_mm_init:
	ttm_bo_device_release(&vgdev->mman.bdev);
	err_dev_init:
	virtio_gpu_ttm_global_fini(vgdev);
	return r;
	}

	void virtio_gpu_ttm_fini(struct virtio_gpu_device *vgdev)
	{
	ttm_bo_device_release(&vgdev->mman.bdev);
	virtio_gpu_ttm_global_fini(vgdev);
	DRM_INFO("virtio_gpu: ttm finalized\n");
	}