drivers/gpu/drm/vmwgfx/vmwgfx_context.c - arm/linux-arm64-legacy - Git at Google

 /**************************************************************************
  *
  * Copyright © 2009-2012 VMware, Inc., Palo Alto, CA., USA
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
  * distribute, 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 "vmwgfx_drv.h"
 #include "vmwgfx_resource_priv.h"
 #include "ttm/ttm_placement.h"

 struct vmw_user_context {
 	struct ttm_base_object base;
 	struct vmw_resource res;
 };

 static void vmw_user_context_free(struct vmw_resource *res);
 static struct vmw_resource *
 vmw_user_context_base_to_res(struct ttm_base_object *base);

 static int vmw_gb_context_create(struct vmw_resource *res);
 static int vmw_gb_context_bind(struct vmw_resource *res,
 			       struct ttm_validate_buffer *val_buf);
 static int vmw_gb_context_unbind(struct vmw_resource *res,
 				 bool readback,
 				 struct ttm_validate_buffer *val_buf);
 static int vmw_gb_context_destroy(struct vmw_resource *res);

 static uint64_t vmw_user_context_size;

 static const struct vmw_user_resource_conv user_context_conv = {
 	.object_type = VMW_RES_CONTEXT,
 	.base_obj_to_res = vmw_user_context_base_to_res,
 	.res_free = vmw_user_context_free
 };

 const struct vmw_user_resource_conv *user_context_converter =
 	&user_context_conv;


 static const struct vmw_res_func vmw_legacy_context_func = {
 	.res_type = vmw_res_context,
 	.needs_backup = false,
 	.may_evict = false,
 	.type_name = "legacy contexts",
 	.backup_placement = NULL,
 	.create = NULL,
 	.destroy = NULL,
 	.bind = NULL,
 	.unbind = NULL
 };

 static const struct vmw_res_func vmw_gb_context_func = {
 	.res_type = vmw_res_context,
 	.needs_backup = true,
 	.may_evict = true,
 	.type_name = "guest backed contexts",
 	.backup_placement = &vmw_mob_placement,
 	.create = vmw_gb_context_create,
 	.destroy = vmw_gb_context_destroy,
 	.bind = vmw_gb_context_bind,
 	.unbind = vmw_gb_context_unbind
 };

 /**
  * Context management:
  */

 static void vmw_hw_context_destroy(struct vmw_resource *res)
 {

 	struct vmw_private *dev_priv = res->dev_priv;
 	struct {
 		SVGA3dCmdHeader header;
 		SVGA3dCmdDestroyContext body;
 	} *cmd;


 	if (res->func->destroy == vmw_gb_context_destroy) {
 		mutex_lock(&dev_priv->cmdbuf_mutex);
 		(void) vmw_gb_context_destroy(res);
 		if (dev_priv->pinned_bo != NULL &&
 		    !dev_priv->query_cid_valid)
 			__vmw_execbuf_release_pinned_bo(dev_priv, NULL);
 		mutex_unlock(&dev_priv->cmdbuf_mutex);
 		return;
 	}

 	vmw_execbuf_release_pinned_bo(dev_priv);
 	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
 	if (unlikely(cmd == NULL)) {
 		DRM_ERROR("Failed reserving FIFO space for surface "
 			  "destruction.\n");
 		return;
 	}

 	cmd->header.id = cpu_to_le32(SVGA_3D_CMD_CONTEXT_DESTROY);
 	cmd->header.size = cpu_to_le32(sizeof(cmd->body));
 	cmd->body.cid = cpu_to_le32(res->id);

 	vmw_fifo_commit(dev_priv, sizeof(*cmd));
 	vmw_3d_resource_dec(dev_priv, false);
 }

 static int vmw_gb_context_init(struct vmw_private *dev_priv,
 			       struct vmw_resource *res,
 			       void (*res_free) (struct vmw_resource *res))
 {
 	int ret;

 	ret = vmw_resource_init(dev_priv, res, true,
 				res_free, &vmw_gb_context_func);
 	res->backup_size = SVGA3D_CONTEXT_DATA_SIZE;

 	if (unlikely(ret != 0)) {
 		if (res_free)
 			res_free(res);
 		else
 			kfree(res);
 		return ret;
 	}

 	vmw_resource_activate(res, vmw_hw_context_destroy);
 	return 0;
 }

 static int vmw_context_init(struct vmw_private *dev_priv,
 			    struct vmw_resource *res,
 			    void (*res_free) (struct vmw_resource *res))
 {
 	int ret;

 	struct {
 		SVGA3dCmdHeader header;
 		SVGA3dCmdDefineContext body;
 	} *cmd;

 	if (dev_priv->has_mob)
 		return vmw_gb_context_init(dev_priv, res, res_free);

 	ret = vmw_resource_init(dev_priv, res, false,
 				res_free, &vmw_legacy_context_func);

 	if (unlikely(ret != 0)) {
 		DRM_ERROR("Failed to allocate a resource id.\n");
 		goto out_early;
 	}

 	if (unlikely(res->id >= SVGA3D_MAX_CONTEXT_IDS)) {
 		DRM_ERROR("Out of hw context ids.\n");
 		vmw_resource_unreference(&res);
 		return -ENOMEM;
 	}

 	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
 	if (unlikely(cmd == NULL)) {
 		DRM_ERROR("Fifo reserve failed.\n");
 		vmw_resource_unreference(&res);
 		return -ENOMEM;
 	}

 	cmd->header.id = cpu_to_le32(SVGA_3D_CMD_CONTEXT_DEFINE);
 	cmd->header.size = cpu_to_le32(sizeof(cmd->body));
 	cmd->body.cid = cpu_to_le32(res->id);

 	vmw_fifo_commit(dev_priv, sizeof(*cmd));
 	(void) vmw_3d_resource_inc(dev_priv, false);
 	vmw_resource_activate(res, vmw_hw_context_destroy);
 	return 0;

 out_early:
 	if (res_free == NULL)
 		kfree(res);
 	else
 		res_free(res);
 	return ret;
 }

 struct vmw_resource *vmw_context_alloc(struct vmw_private *dev_priv)
 {
 	struct vmw_resource *res = kmalloc(sizeof(*res), GFP_KERNEL);
 	int ret;

 	if (unlikely(res == NULL))
 		return NULL;

 	ret = vmw_context_init(dev_priv, res, NULL);

 	return (ret == 0) ? res : NULL;
 }


 static int vmw_gb_context_create(struct vmw_resource *res)
 {
 	struct vmw_private *dev_priv = res->dev_priv;
 	int ret;
 	struct {
 		SVGA3dCmdHeader header;
 		SVGA3dCmdDefineGBContext body;
 	} *cmd;

 	if (likely(res->id != -1))
 		return 0;

 	ret = vmw_resource_alloc_id(res);
 	if (unlikely(ret != 0)) {
 		DRM_ERROR("Failed to allocate a context id.\n");
 		goto out_no_id;
 	}

 	if (unlikely(res->id >= VMWGFX_NUM_GB_CONTEXT)) {
 		ret = -EBUSY;
 		goto out_no_fifo;
 	}

 	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
 	if (unlikely(cmd == NULL)) {
 		DRM_ERROR("Failed reserving FIFO space for context "
 			  "creation.\n");
 		ret = -ENOMEM;
 		goto out_no_fifo;
 	}

 	cmd->header.id = SVGA_3D_CMD_DEFINE_GB_CONTEXT;
 	cmd->header.size = sizeof(cmd->body);
 	cmd->body.cid = res->id;
 	vmw_fifo_commit(dev_priv, sizeof(*cmd));
 	(void) vmw_3d_resource_inc(dev_priv, false);

 	return 0;

 out_no_fifo:
 	vmw_resource_release_id(res);
 out_no_id:
 	return ret;
 }

 static int vmw_gb_context_bind(struct vmw_resource *res,
 			       struct ttm_validate_buffer *val_buf)
 {
 	struct vmw_private *dev_priv = res->dev_priv;
 	struct {
 		SVGA3dCmdHeader header;
 		SVGA3dCmdBindGBContext body;
 	} *cmd;
 	struct ttm_buffer_object *bo = val_buf->bo;

 	BUG_ON(bo->mem.mem_type != VMW_PL_MOB);

 	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
 	if (unlikely(cmd == NULL)) {
 		DRM_ERROR("Failed reserving FIFO space for context "
 			  "binding.\n");
 		return -ENOMEM;
 	}

 	cmd->header.id = SVGA_3D_CMD_BIND_GB_CONTEXT;
 	cmd->header.size = sizeof(cmd->body);
 	cmd->body.cid = res->id;
 	cmd->body.mobid = bo->mem.start;
 	cmd->body.validContents = res->backup_dirty;
 	res->backup_dirty = false;
 	vmw_fifo_commit(dev_priv, sizeof(*cmd));

 	return 0;
 }

 static int vmw_gb_context_unbind(struct vmw_resource *res,
 				 bool readback,
 				 struct ttm_validate_buffer *val_buf)
 {
 	struct vmw_private *dev_priv = res->dev_priv;
 	struct ttm_buffer_object *bo = val_buf->bo;
 	struct vmw_fence_obj *fence;

 	struct {
 		SVGA3dCmdHeader header;
 		SVGA3dCmdReadbackGBContext body;
 	} *cmd1;
 	struct {
 		SVGA3dCmdHeader header;
 		SVGA3dCmdBindGBContext body;
 	} *cmd2;
 	uint32_t submit_size;
 	uint8_t *cmd;


 	BUG_ON(bo->mem.mem_type != VMW_PL_MOB);

 	submit_size = sizeof(*cmd2) + (readback ? sizeof(*cmd1) : 0);

 	cmd = vmw_fifo_reserve(dev_priv, submit_size);
 	if (unlikely(cmd == NULL)) {
 		DRM_ERROR("Failed reserving FIFO space for context "
 			  "unbinding.\n");
 		return -ENOMEM;
 	}

 	cmd2 = (void *) cmd;
 	if (readback) {
 		cmd1 = (void *) cmd;
 		cmd1->header.id = SVGA_3D_CMD_READBACK_GB_CONTEXT;
 		cmd1->header.size = sizeof(cmd1->body);
 		cmd1->body.cid = res->id;
 		cmd2 = (void *) (&cmd1[1]);
 	}
 	cmd2->header.id = SVGA_3D_CMD_BIND_GB_CONTEXT;
 	cmd2->header.size = sizeof(cmd2->body);
 	cmd2->body.cid = res->id;
 	cmd2->body.mobid = SVGA3D_INVALID_ID;

 	vmw_fifo_commit(dev_priv, submit_size);

 	/*
 	 * Create a fence object and fence the backup buffer.
 	 */

 	(void) vmw_execbuf_fence_commands(NULL, dev_priv,
 					  &fence, NULL);

 	vmw_fence_single_bo(bo, fence);

 	if (likely(fence != NULL))
 		vmw_fence_obj_unreference(&fence);

 	return 0;
 }

 static int vmw_gb_context_destroy(struct vmw_resource *res)
 {
 	struct vmw_private *dev_priv = res->dev_priv;
 	struct {
 		SVGA3dCmdHeader header;
 		SVGA3dCmdDestroyGBContext body;
 	} *cmd;

 	if (likely(res->id == -1))
 		return 0;

 	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
 	if (unlikely(cmd == NULL)) {
 		DRM_ERROR("Failed reserving FIFO space for context "
 			  "destruction.\n");
 		return -ENOMEM;
 	}

 	cmd->header.id = SVGA_3D_CMD_DESTROY_GB_CONTEXT;
 	cmd->header.size = sizeof(cmd->body);
 	cmd->body.cid = res->id;
 	vmw_fifo_commit(dev_priv, sizeof(*cmd));
 	if (dev_priv->query_cid == res->id)
 		dev_priv->query_cid_valid = false;
 	vmw_resource_release_id(res);
 	vmw_3d_resource_dec(dev_priv, false);

 	return 0;
 }

 /**
  * User-space context management:
  */

 static struct vmw_resource *
 vmw_user_context_base_to_res(struct ttm_base_object *base)
 {
 	return &(container_of(base, struct vmw_user_context, base)->res);
 }

 static void vmw_user_context_free(struct vmw_resource *res)
 {
 	struct vmw_user_context *ctx =
 	    container_of(res, struct vmw_user_context, res);
 	struct vmw_private *dev_priv = res->dev_priv;

 	ttm_base_object_kfree(ctx, base);
 	ttm_mem_global_free(vmw_mem_glob(dev_priv),
 			    vmw_user_context_size);
 }

 /**
  * This function is called when user space has no more references on the
  * base object. It releases the base-object's reference on the resource object.
  */

 static void vmw_user_context_base_release(struct ttm_base_object **p_base)
 {
 	struct ttm_base_object *base = *p_base;
 	struct vmw_user_context *ctx =
 	    container_of(base, struct vmw_user_context, base);
 	struct vmw_resource *res = &ctx->res;

 	*p_base = NULL;
 	vmw_resource_unreference(&res);
 }

 int vmw_context_destroy_ioctl(struct drm_device *dev, void *data,
 			      struct drm_file *file_priv)
 {
 	struct drm_vmw_context_arg *arg = (struct drm_vmw_context_arg *)data;
 	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;

 	return ttm_ref_object_base_unref(tfile, arg->cid, TTM_REF_USAGE);
 }

 int vmw_context_define_ioctl(struct drm_device *dev, void *data,
 			     struct drm_file *file_priv)
 {
 	struct vmw_private *dev_priv = vmw_priv(dev);
 	struct vmw_user_context *ctx;
 	struct vmw_resource *res;
 	struct vmw_resource *tmp;
 	struct drm_vmw_context_arg *arg = (struct drm_vmw_context_arg *)data;
 	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
 	struct vmw_master *vmaster = vmw_master(file_priv->master);
 	int ret;


 	/*
 	 * Approximate idr memory usage with 128 bytes. It will be limited
 	 * by maximum number_of contexts anyway.
 	 */

 	if (unlikely(vmw_user_context_size == 0))
 		vmw_user_context_size = ttm_round_pot(sizeof(*ctx)) + 128;

 	ret = ttm_read_lock(&vmaster->lock, true);
 	if (unlikely(ret != 0))
 		return ret;

 	ret = ttm_mem_global_alloc(vmw_mem_glob(dev_priv),
 				   vmw_user_context_size,
 				   false, true);
 	if (unlikely(ret != 0)) {
 		if (ret != -ERESTARTSYS)
 			DRM_ERROR("Out of graphics memory for context"
 				  " creation.\n");
 		goto out_unlock;
 	}

 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (unlikely(ctx == NULL)) {
 		ttm_mem_global_free(vmw_mem_glob(dev_priv),
 				    vmw_user_context_size);
 		ret = -ENOMEM;
 		goto out_unlock;
 	}

 	res = &ctx->res;
 	ctx->base.shareable = false;
 	ctx->base.tfile = NULL;

 	/*
 	 * From here on, the destructor takes over resource freeing.
 	 */

 	ret = vmw_context_init(dev_priv, res, vmw_user_context_free);
 	if (unlikely(ret != 0))
 		goto out_unlock;

 	tmp = vmw_resource_reference(&ctx->res);
 	ret = ttm_base_object_init(tfile, &ctx->base, false, VMW_RES_CONTEXT,
 				   &vmw_user_context_base_release, NULL);

 	if (unlikely(ret != 0)) {
 		vmw_resource_unreference(&tmp);
 		goto out_err;
 	}

 	arg->cid = ctx->base.hash.key;
 out_err:
 	vmw_resource_unreference(&res);
 out_unlock:
 	ttm_read_unlock(&vmaster->lock);
 	return ret;

 }
	/**************************************************************************
	*
	* Copyright © 2009-2012 VMware, Inc., Palo Alto, CA., USA
	* All Rights Reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, 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 "vmwgfx_drv.h"
	#include "vmwgfx_resource_priv.h"
	#include "ttm/ttm_placement.h"

	struct vmw_user_context {
	struct ttm_base_object base;
	struct vmw_resource res;
	};

	static void vmw_user_context_free(struct vmw_resource *res);
	static struct vmw_resource *
	vmw_user_context_base_to_res(struct ttm_base_object *base);

	static int vmw_gb_context_create(struct vmw_resource *res);
	static int vmw_gb_context_bind(struct vmw_resource *res,
	struct ttm_validate_buffer *val_buf);
	static int vmw_gb_context_unbind(struct vmw_resource *res,
	bool readback,
	struct ttm_validate_buffer *val_buf);
	static int vmw_gb_context_destroy(struct vmw_resource *res);

	static uint64_t vmw_user_context_size;

	static const struct vmw_user_resource_conv user_context_conv = {
	.object_type = VMW_RES_CONTEXT,
	.base_obj_to_res = vmw_user_context_base_to_res,
	.res_free = vmw_user_context_free
	};

	const struct vmw_user_resource_conv *user_context_converter =
	&user_context_conv;


	static const struct vmw_res_func vmw_legacy_context_func = {
	.res_type = vmw_res_context,
	.needs_backup = false,
	.may_evict = false,
	.type_name = "legacy contexts",
	.backup_placement = NULL,
	.create = NULL,
	.destroy = NULL,
	.bind = NULL,
	.unbind = NULL
	};

	static const struct vmw_res_func vmw_gb_context_func = {
	.res_type = vmw_res_context,
	.needs_backup = true,
	.may_evict = true,
	.type_name = "guest backed contexts",
	.backup_placement = &vmw_mob_placement,
	.create = vmw_gb_context_create,
	.destroy = vmw_gb_context_destroy,
	.bind = vmw_gb_context_bind,
	.unbind = vmw_gb_context_unbind
	};

	/**
	* Context management:
	*/

	static void vmw_hw_context_destroy(struct vmw_resource *res)
	{

	struct vmw_private *dev_priv = res->dev_priv;
	struct {
	SVGA3dCmdHeader header;
	SVGA3dCmdDestroyContext body;
	} *cmd;


	if (res->func->destroy == vmw_gb_context_destroy) {
	mutex_lock(&dev_priv->cmdbuf_mutex);
	(void) vmw_gb_context_destroy(res);
	if (dev_priv->pinned_bo != NULL &&
	!dev_priv->query_cid_valid)
	__vmw_execbuf_release_pinned_bo(dev_priv, NULL);
	mutex_unlock(&dev_priv->cmdbuf_mutex);
	return;
	}

	vmw_execbuf_release_pinned_bo(dev_priv);
	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
	if (unlikely(cmd == NULL)) {
	DRM_ERROR("Failed reserving FIFO space for surface "
	"destruction.\n");
	return;
	}

	cmd->header.id = cpu_to_le32(SVGA_3D_CMD_CONTEXT_DESTROY);
	cmd->header.size = cpu_to_le32(sizeof(cmd->body));
	cmd->body.cid = cpu_to_le32(res->id);

	vmw_fifo_commit(dev_priv, sizeof(*cmd));
	vmw_3d_resource_dec(dev_priv, false);
	}

	static int vmw_gb_context_init(struct vmw_private *dev_priv,
	struct vmw_resource *res,
	void (res_free) (struct vmw_resource res))
	{
	int ret;

	ret = vmw_resource_init(dev_priv, res, true,
	res_free, &vmw_gb_context_func);
	res->backup_size = SVGA3D_CONTEXT_DATA_SIZE;

	if (unlikely(ret != 0)) {
	if (res_free)
	res_free(res);
	else
	kfree(res);
	return ret;
	}

	vmw_resource_activate(res, vmw_hw_context_destroy);
	return 0;
	}

	static int vmw_context_init(struct vmw_private *dev_priv,
	struct vmw_resource *res,
	void (res_free) (struct vmw_resource res))
	{
	int ret;

	struct {
	SVGA3dCmdHeader header;
	SVGA3dCmdDefineContext body;
	} *cmd;

	if (dev_priv->has_mob)
	return vmw_gb_context_init(dev_priv, res, res_free);

	ret = vmw_resource_init(dev_priv, res, false,
	res_free, &vmw_legacy_context_func);

	if (unlikely(ret != 0)) {
	DRM_ERROR("Failed to allocate a resource id.\n");
	goto out_early;
	}

	if (unlikely(res->id >= SVGA3D_MAX_CONTEXT_IDS)) {
	DRM_ERROR("Out of hw context ids.\n");
	vmw_resource_unreference(&res);
	return -ENOMEM;
	}

	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
	if (unlikely(cmd == NULL)) {
	DRM_ERROR("Fifo reserve failed.\n");
	vmw_resource_unreference(&res);
	return -ENOMEM;
	}

	cmd->header.id = cpu_to_le32(SVGA_3D_CMD_CONTEXT_DEFINE);
	cmd->header.size = cpu_to_le32(sizeof(cmd->body));
	cmd->body.cid = cpu_to_le32(res->id);

	vmw_fifo_commit(dev_priv, sizeof(*cmd));
	(void) vmw_3d_resource_inc(dev_priv, false);
	vmw_resource_activate(res, vmw_hw_context_destroy);
	return 0;

	out_early:
	if (res_free == NULL)
	kfree(res);
	else
	res_free(res);
	return ret;
	}

	struct vmw_resource vmw_context_alloc(struct vmw_private dev_priv)
	{
	struct vmw_resource res = kmalloc(sizeof(res), GFP_KERNEL);
	int ret;

	if (unlikely(res == NULL))
	return NULL;

	ret = vmw_context_init(dev_priv, res, NULL);

	return (ret == 0) ? res : NULL;
	}


	static int vmw_gb_context_create(struct vmw_resource *res)
	{
	struct vmw_private *dev_priv = res->dev_priv;
	int ret;
	struct {
	SVGA3dCmdHeader header;
	SVGA3dCmdDefineGBContext body;
	} *cmd;

	if (likely(res->id != -1))
	return 0;

	ret = vmw_resource_alloc_id(res);
	if (unlikely(ret != 0)) {
	DRM_ERROR("Failed to allocate a context id.\n");
	goto out_no_id;
	}

	if (unlikely(res->id >= VMWGFX_NUM_GB_CONTEXT)) {
	ret = -EBUSY;
	goto out_no_fifo;
	}

	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
	if (unlikely(cmd == NULL)) {
	DRM_ERROR("Failed reserving FIFO space for context "
	"creation.\n");
	ret = -ENOMEM;
	goto out_no_fifo;
	}

	cmd->header.id = SVGA_3D_CMD_DEFINE_GB_CONTEXT;
	cmd->header.size = sizeof(cmd->body);
	cmd->body.cid = res->id;
	vmw_fifo_commit(dev_priv, sizeof(*cmd));
	(void) vmw_3d_resource_inc(dev_priv, false);

	return 0;

	out_no_fifo:
	vmw_resource_release_id(res);
	out_no_id:
	return ret;
	}

	static int vmw_gb_context_bind(struct vmw_resource *res,
	struct ttm_validate_buffer *val_buf)
	{
	struct vmw_private *dev_priv = res->dev_priv;
	struct {
	SVGA3dCmdHeader header;
	SVGA3dCmdBindGBContext body;
	} *cmd;
	struct ttm_buffer_object *bo = val_buf->bo;

	BUG_ON(bo->mem.mem_type != VMW_PL_MOB);

	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
	if (unlikely(cmd == NULL)) {
	DRM_ERROR("Failed reserving FIFO space for context "
	"binding.\n");
	return -ENOMEM;
	}

	cmd->header.id = SVGA_3D_CMD_BIND_GB_CONTEXT;
	cmd->header.size = sizeof(cmd->body);
	cmd->body.cid = res->id;
	cmd->body.mobid = bo->mem.start;
	cmd->body.validContents = res->backup_dirty;
	res->backup_dirty = false;
	vmw_fifo_commit(dev_priv, sizeof(*cmd));

	return 0;
	}

	static int vmw_gb_context_unbind(struct vmw_resource *res,
	bool readback,
	struct ttm_validate_buffer *val_buf)
	{
	struct vmw_private *dev_priv = res->dev_priv;
	struct ttm_buffer_object *bo = val_buf->bo;
	struct vmw_fence_obj *fence;

	struct {
	SVGA3dCmdHeader header;
	SVGA3dCmdReadbackGBContext body;
	} *cmd1;
	struct {
	SVGA3dCmdHeader header;
	SVGA3dCmdBindGBContext body;
	} *cmd2;
	uint32_t submit_size;
	uint8_t *cmd;


	BUG_ON(bo->mem.mem_type != VMW_PL_MOB);

	submit_size = sizeof(cmd2) + (readback ? sizeof(cmd1) : 0);

	cmd = vmw_fifo_reserve(dev_priv, submit_size);
	if (unlikely(cmd == NULL)) {
	DRM_ERROR("Failed reserving FIFO space for context "
	"unbinding.\n");
	return -ENOMEM;
	}

	cmd2 = (void *) cmd;
	if (readback) {
	cmd1 = (void *) cmd;
	cmd1->header.id = SVGA_3D_CMD_READBACK_GB_CONTEXT;
	cmd1->header.size = sizeof(cmd1->body);
	cmd1->body.cid = res->id;
	cmd2 = (void *) (&cmd1[1]);
	}
	cmd2->header.id = SVGA_3D_CMD_BIND_GB_CONTEXT;
	cmd2->header.size = sizeof(cmd2->body);
	cmd2->body.cid = res->id;
	cmd2->body.mobid = SVGA3D_INVALID_ID;

	vmw_fifo_commit(dev_priv, submit_size);

	/*
	* Create a fence object and fence the backup buffer.
	*/

	(void) vmw_execbuf_fence_commands(NULL, dev_priv,
	&fence, NULL);

	vmw_fence_single_bo(bo, fence);

	if (likely(fence != NULL))
	vmw_fence_obj_unreference(&fence);

	return 0;
	}

	static int vmw_gb_context_destroy(struct vmw_resource *res)
	{
	struct vmw_private *dev_priv = res->dev_priv;
	struct {
	SVGA3dCmdHeader header;
	SVGA3dCmdDestroyGBContext body;
	} *cmd;

	if (likely(res->id == -1))
	return 0;

	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
	if (unlikely(cmd == NULL)) {
	DRM_ERROR("Failed reserving FIFO space for context "
	"destruction.\n");
	return -ENOMEM;
	}

	cmd->header.id = SVGA_3D_CMD_DESTROY_GB_CONTEXT;
	cmd->header.size = sizeof(cmd->body);
	cmd->body.cid = res->id;
	vmw_fifo_commit(dev_priv, sizeof(*cmd));
	if (dev_priv->query_cid == res->id)
	dev_priv->query_cid_valid = false;
	vmw_resource_release_id(res);
	vmw_3d_resource_dec(dev_priv, false);

	return 0;
	}

	/**
	* User-space context management:
	*/

	static struct vmw_resource *
	vmw_user_context_base_to_res(struct ttm_base_object *base)
	{
	return &(container_of(base, struct vmw_user_context, base)->res);
	}

	static void vmw_user_context_free(struct vmw_resource *res)
	{
	struct vmw_user_context *ctx =
	container_of(res, struct vmw_user_context, res);
	struct vmw_private *dev_priv = res->dev_priv;

	ttm_base_object_kfree(ctx, base);
	ttm_mem_global_free(vmw_mem_glob(dev_priv),
	vmw_user_context_size);
	}

	/**
	* This function is called when user space has no more references on the
	* base object. It releases the base-object's reference on the resource object.
	*/

	static void vmw_user_context_base_release(struct ttm_base_object **p_base)
	{
	struct ttm_base_object base = p_base;
	struct vmw_user_context *ctx =
	container_of(base, struct vmw_user_context, base);
	struct vmw_resource *res = &ctx->res;

	*p_base = NULL;
	vmw_resource_unreference(&res);
	}

	int vmw_context_destroy_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	struct drm_vmw_context_arg arg = (struct drm_vmw_context_arg )data;
	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;

	return ttm_ref_object_base_unref(tfile, arg->cid, TTM_REF_USAGE);
	}

	int vmw_context_define_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	struct vmw_private *dev_priv = vmw_priv(dev);
	struct vmw_user_context *ctx;
	struct vmw_resource *res;
	struct vmw_resource *tmp;
	struct drm_vmw_context_arg arg = (struct drm_vmw_context_arg )data;
	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
	struct vmw_master *vmaster = vmw_master(file_priv->master);
	int ret;


	/*
	* Approximate idr memory usage with 128 bytes. It will be limited
	* by maximum number_of contexts anyway.
	*/

	if (unlikely(vmw_user_context_size == 0))
	vmw_user_context_size = ttm_round_pot(sizeof(*ctx)) + 128;

	ret = ttm_read_lock(&vmaster->lock, true);
	if (unlikely(ret != 0))
	return ret;

	ret = ttm_mem_global_alloc(vmw_mem_glob(dev_priv),
	vmw_user_context_size,
	false, true);
	if (unlikely(ret != 0)) {
	if (ret != -ERESTARTSYS)
	DRM_ERROR("Out of graphics memory for context"
	" creation.\n");
	goto out_unlock;
	}

	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
	if (unlikely(ctx == NULL)) {
	ttm_mem_global_free(vmw_mem_glob(dev_priv),
	vmw_user_context_size);
	ret = -ENOMEM;
	goto out_unlock;
	}

	res = &ctx->res;
	ctx->base.shareable = false;
	ctx->base.tfile = NULL;

	/*
	* From here on, the destructor takes over resource freeing.
	*/

	ret = vmw_context_init(dev_priv, res, vmw_user_context_free);
	if (unlikely(ret != 0))
	goto out_unlock;

	tmp = vmw_resource_reference(&ctx->res);
	ret = ttm_base_object_init(tfile, &ctx->base, false, VMW_RES_CONTEXT,
	&vmw_user_context_base_release, NULL);

	if (unlikely(ret != 0)) {
	vmw_resource_unreference(&tmp);
	goto out_err;
	}

	arg->cid = ctx->base.hash.key;
	out_err:
	vmw_resource_unreference(&res);
	out_unlock:
	ttm_read_unlock(&vmaster->lock);
	return ret;

	}