[linux.git] / drivers / xen / gntdev.c

/******************************************************************************
 * gntdev.c
 *
 * Device for accessing (in user-space) pages that have been granted by other
 * domains.
 *
 * Copyright (c) 2006-2007, D G Murray.
 *           (c) 2009 Gerd Hoffmann <[email protected]>
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#undef DEBUG

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/mmu_notifier.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/slab.h>

#include <xen/xen.h>
#include <xen/grant_table.h>
#include <xen/gntdev.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/page.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Derek G. Murray <[email protected]>, "
	      "Gerd Hoffmann <[email protected]>");
MODULE_DESCRIPTION("User-space granted page access driver");

static int limit = 1024;
module_param(limit, int, 0644);
MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped at "
		"once by a gntdev instance");

struct gntdev_priv {
	struct list_head maps;
	uint32_t used;
	uint32_t limit;
	/* lock protects maps from concurrent changes */
	spinlock_t lock;
	struct mm_struct *mm;
	struct mmu_notifier mn;
};

struct grant_map {
	struct list_head next;
	struct gntdev_priv *priv;
	struct vm_area_struct *vma;
	int index;
	int count;
	int flags;
	int is_mapped;
	struct ioctl_gntdev_grant_ref *grants;
	struct gnttab_map_grant_ref   *map_ops;
	struct gnttab_unmap_grant_ref *unmap_ops;
	struct page **pages;
};

/* ------------------------------------------------------------------ */

static void gntdev_print_maps(struct gntdev_priv *priv,
			      char *text, int text_index)
{
#ifdef DEBUG
	struct grant_map *map;

	pr_debug("maps list (priv %p, usage %d/%d)\n",
	       priv, priv->used, priv->limit);

	list_for_each_entry(map, &priv->maps, next)
		pr_debug("  index %2d, count %2d %s\n",
		       map->index, map->count,
		       map->index == text_index && text ? text : "");
#endif
}

static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
{
	struct grant_map *add;
	int i;

	add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
	if (NULL == add)
		return NULL;

	add->grants    = kzalloc(sizeof(add->grants[0])    * count, GFP_KERNEL);
	add->map_ops   = kzalloc(sizeof(add->map_ops[0])   * count, GFP_KERNEL);
	add->unmap_ops = kzalloc(sizeof(add->unmap_ops[0]) * count, GFP_KERNEL);
	add->pages     = kzalloc(sizeof(add->pages[0])     * count, GFP_KERNEL);
	if (NULL == add->grants    ||
	    NULL == add->map_ops   ||
	    NULL == add->unmap_ops ||
	    NULL == add->pages)
		goto err;

	for (i = 0; i < count; i++) {
		add->pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
		if (add->pages[i] == NULL)
			goto err;
	}

	add->index = 0;
	add->count = count;
	add->priv  = priv;

	if (add->count + priv->used > priv->limit)
		goto err;

	return add;

err:
	if (add->pages)
		for (i = 0; i < count; i++) {
			if (add->pages[i])
				__free_page(add->pages[i]);
		}
	kfree(add->pages);
	kfree(add->grants);
	kfree(add->map_ops);
	kfree(add->unmap_ops);
	kfree(add);
	return NULL;
}

static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
{
	struct grant_map *map;

	list_for_each_entry(map, &priv->maps, next) {
		if (add->index + add->count < map->index) {
			list_add_tail(&add->next, &map->next);
			goto done;
		}
		add->index = map->index + map->count;
	}
	list_add_tail(&add->next, &priv->maps);

done:
	priv->used += add->count;
	gntdev_print_maps(priv, "[new]", add->index);
}

static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
		int index, int count)
{
	struct grant_map *map;

	list_for_each_entry(map, &priv->maps, next) {
		if (map->index != index)
			continue;
		if (map->count != count)
			continue;
		return map;
	}
	return NULL;
}

static struct grant_map *gntdev_find_map_vaddr(struct gntdev_priv *priv,
					       unsigned long vaddr)
{
	struct grant_map *map;

	list_for_each_entry(map, &priv->maps, next) {
		if (!map->vma)
			continue;
		if (vaddr < map->vma->vm_start)
			continue;
		if (vaddr >= map->vma->vm_end)
			continue;
		return map;
	}
	return NULL;
}

static int gntdev_del_map(struct grant_map *map)
{
	int i;

	if (map->vma)
		return -EBUSY;
	for (i = 0; i < map->count; i++)
		if (map->unmap_ops[i].handle)
			return -EBUSY;

	map->priv->used -= map->count;
	list_del(&map->next);
	return 0;
}

static void gntdev_free_map(struct grant_map *map)
{
	int i;

	if (!map)
		return;

	if (map->pages)
		for (i = 0; i < map->count; i++) {
			if (map->pages[i])
				__free_page(map->pages[i]);
		}
	kfree(map->pages);
	kfree(map->grants);
	kfree(map->map_ops);
	kfree(map->unmap_ops);
	kfree(map);
}

/* ------------------------------------------------------------------ */

static int find_grant_ptes(pte_t *pte, pgtable_t token,
		unsigned long addr, void *data)
{
	struct grant_map *map = data;
	unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
	u64 pte_maddr;

	BUG_ON(pgnr >= map->count);
	pte_maddr = arbitrary_virt_to_machine(pte).maddr;

	gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr,
			  GNTMAP_contains_pte | map->flags,
			  map->grants[pgnr].ref,
			  map->grants[pgnr].domid);
	gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr,
			    GNTMAP_contains_pte | map->flags,
			    0 /* handle */);
	return 0;
}

static int map_grant_pages(struct grant_map *map)
{
	int i, err = 0;

	pr_debug("map %d+%d\n", map->index, map->count);
	err = gnttab_map_refs(map->map_ops, map->pages, map->count);
	if (err)
		return err;

	for (i = 0; i < map->count; i++) {
		if (map->map_ops[i].status)
			err = -EINVAL;
		map->unmap_ops[i].handle = map->map_ops[i].handle;
	}
	return err;
}

static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
{
	int i, err = 0;

	pr_debug("map %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
	err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages, pages);
	if (err)
		return err;

	for (i = 0; i < pages; i++) {
		if (map->unmap_ops[offset+i].status)
			err = -EINVAL;
		map->unmap_ops[offset+i].handle = 0;
	}
	return err;
}

/* ------------------------------------------------------------------ */

static void gntdev_vma_close(struct vm_area_struct *vma)
{
	struct grant_map *map = vma->vm_private_data;

	pr_debug("close %p\n", vma);
	map->is_mapped = 0;
	map->vma = NULL;
	vma->vm_private_data = NULL;
}

static int gntdev_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	pr_debug("vaddr %p, pgoff %ld (shouldn't happen)\n",
			vmf->virtual_address, vmf->pgoff);
	vmf->flags = VM_FAULT_ERROR;
	return 0;
}

static struct vm_operations_struct gntdev_vmops = {
	.close = gntdev_vma_close,
	.fault = gntdev_vma_fault,
};

/* ------------------------------------------------------------------ */

static void mn_invl_range_start(struct mmu_notifier *mn,
				struct mm_struct *mm,
				unsigned long start, unsigned long end)
{
	struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
	struct grant_map *map;
	unsigned long mstart, mend;
	int err;

	spin_lock(&priv->lock);
	list_for_each_entry(map, &priv->maps, next) {
		if (!map->vma)
			continue;
		if (!map->is_mapped)
			continue;
		if (map->vma->vm_start >= end)
			continue;
		if (map->vma->vm_end <= start)
			continue;
		mstart = max(start, map->vma->vm_start);
		mend   = min(end,   map->vma->vm_end);
		pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
				map->index, map->count,
				map->vma->vm_start, map->vma->vm_end,
				start, end, mstart, mend);
		err = unmap_grant_pages(map,
					(mstart - map->vma->vm_start) >> PAGE_SHIFT,
					(mend - mstart) >> PAGE_SHIFT);
		WARN_ON(err);
	}
	spin_unlock(&priv->lock);
}

static void mn_invl_page(struct mmu_notifier *mn,
			 struct mm_struct *mm,
			 unsigned long address)
{
	mn_invl_range_start(mn, mm, address, address + PAGE_SIZE);
}

static void mn_release(struct mmu_notifier *mn,
		       struct mm_struct *mm)
{
	struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
	struct grant_map *map;
	int err;

	spin_lock(&priv->lock);
	list_for_each_entry(map, &priv->maps, next) {
		if (!map->vma)
			continue;
		pr_debug("map %d+%d (%lx %lx)\n",
				map->index, map->count,
				map->vma->vm_start, map->vma->vm_end);
		err = unmap_grant_pages(map, /* offset */ 0, map->count);
		WARN_ON(err);
	}
	spin_unlock(&priv->lock);
}

struct mmu_notifier_ops gntdev_mmu_ops = {
	.release                = mn_release,
	.invalidate_page        = mn_invl_page,
	.invalidate_range_start = mn_invl_range_start,
};

/* ------------------------------------------------------------------ */

static int gntdev_open(struct inode *inode, struct file *flip)
{
	struct gntdev_priv *priv;
	int ret = 0;

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

	INIT_LIST_HEAD(&priv->maps);
	spin_lock_init(&priv->lock);
	priv->limit = limit;

	priv->mm = get_task_mm(current);
	if (!priv->mm) {
		kfree(priv);
		return -ENOMEM;
	}
	priv->mn.ops = &gntdev_mmu_ops;
	ret = mmu_notifier_register(&priv->mn, priv->mm);
	mmput(priv->mm);

	if (ret) {
		kfree(priv);
		return ret;
	}

	flip->private_data = priv;
	pr_debug("priv %p\n", priv);

	return 0;
}

static int gntdev_release(struct inode *inode, struct file *flip)
{
	struct gntdev_priv *priv = flip->private_data;
	struct grant_map *map;
	int err;

	pr_debug("priv %p\n", priv);

	spin_lock(&priv->lock);
	while (!list_empty(&priv->maps)) {
		map = list_entry(priv->maps.next, struct grant_map, next);
		err = gntdev_del_map(map);
		if (WARN_ON(err))
			gntdev_free_map(map);

	}
	spin_unlock(&priv->lock);

	mmu_notifier_unregister(&priv->mn, priv->mm);
	kfree(priv);
	return 0;
}

static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
				       struct ioctl_gntdev_map_grant_ref __user *u)
{
	struct ioctl_gntdev_map_grant_ref op;
	struct grant_map *map;
	int err;

	if (copy_from_user(&op, u, sizeof(op)) != 0)
		return -EFAULT;
	pr_debug("priv %p, add %d\n", priv, op.count);
	if (unlikely(op.count <= 0))
		return -EINVAL;
	if (unlikely(op.count > priv->limit))
		return -EINVAL;

	err = -ENOMEM;
	map = gntdev_alloc_map(priv, op.count);
	if (!map)
		return err;
	if (copy_from_user(map->grants, &u->refs,
			   sizeof(map->grants[0]) * op.count) != 0) {
		gntdev_free_map(map);
		return err;
	}

	spin_lock(&priv->lock);
	gntdev_add_map(priv, map);
	op.index = map->index << PAGE_SHIFT;
	spin_unlock(&priv->lock);

	if (copy_to_user(u, &op, sizeof(op)) != 0) {
		spin_lock(&priv->lock);
		gntdev_del_map(map);
		spin_unlock(&priv->lock);
		gntdev_free_map(map);
		return err;
	}
	return 0;
}

static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
					 struct ioctl_gntdev_unmap_grant_ref __user *u)
{
	struct ioctl_gntdev_unmap_grant_ref op;
	struct grant_map *map;
	int err = -ENOENT;

	if (copy_from_user(&op, u, sizeof(op)) != 0)
		return -EFAULT;
	pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);

	spin_lock(&priv->lock);
	map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
	if (map)
		err = gntdev_del_map(map);
	spin_unlock(&priv->lock);
	if (!err)
		gntdev_free_map(map);
	return err;
}

static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
					      struct ioctl_gntdev_get_offset_for_vaddr __user *u)
{
	struct ioctl_gntdev_get_offset_for_vaddr op;
	struct grant_map *map;

	if (copy_from_user(&op, u, sizeof(op)) != 0)
		return -EFAULT;
	pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);

	spin_lock(&priv->lock);
	map = gntdev_find_map_vaddr(priv, op.vaddr);
	if (map == NULL ||
	    map->vma->vm_start != op.vaddr) {
		spin_unlock(&priv->lock);
		return -EINVAL;
	}
	op.offset = map->index << PAGE_SHIFT;
	op.count = map->count;
	spin_unlock(&priv->lock);

	if (copy_to_user(u, &op, sizeof(op)) != 0)
		return -EFAULT;
	return 0;
}

static long gntdev_ioctl_set_max_grants(struct gntdev_priv *priv,
					struct ioctl_gntdev_set_max_grants __user *u)
{
	struct ioctl_gntdev_set_max_grants op;

	if (copy_from_user(&op, u, sizeof(op)) != 0)
		return -EFAULT;
	pr_debug("priv %p, limit %d\n", priv, op.count);
	if (op.count > limit)
		return -E2BIG;

	spin_lock(&priv->lock);
	priv->limit = op.count;
	spin_unlock(&priv->lock);
	return 0;
}

static long gntdev_ioctl(struct file *flip,
			 unsigned int cmd, unsigned long arg)
{
	struct gntdev_priv *priv = flip->private_data;
	void __user *ptr = (void __user *)arg;

	switch (cmd) {
	case IOCTL_GNTDEV_MAP_GRANT_REF:
		return gntdev_ioctl_map_grant_ref(priv, ptr);

	case IOCTL_GNTDEV_UNMAP_GRANT_REF:
		return gntdev_ioctl_unmap_grant_ref(priv, ptr);

	case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
		return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);

	case IOCTL_GNTDEV_SET_MAX_GRANTS:
		return gntdev_ioctl_set_max_grants(priv, ptr);

	default:
		pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
		return -ENOIOCTLCMD;
	}

	return 0;
}

static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
{
	struct gntdev_priv *priv = flip->private_data;
	int index = vma->vm_pgoff;
	int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
	struct grant_map *map;
	int err = -EINVAL;

	if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	pr_debug("map %d+%d at %lx (pgoff %lx)\n",
			index, count, vma->vm_start, vma->vm_pgoff);

	spin_lock(&priv->lock);
	map = gntdev_find_map_index(priv, index, count);
	if (!map)
		goto unlock_out;
	if (map->vma)
		goto unlock_out;
	if (priv->mm != vma->vm_mm) {
		printk(KERN_WARNING "Huh? Other mm?\n");
		goto unlock_out;
	}

	vma->vm_ops = &gntdev_vmops;

	vma->vm_flags |= VM_RESERVED|VM_DONTCOPY|VM_DONTEXPAND|VM_PFNMAP;

	vma->vm_private_data = map;
	map->vma = vma;

	map->flags = GNTMAP_host_map | GNTMAP_application_map;
	if (!(vma->vm_flags & VM_WRITE))
		map->flags |= GNTMAP_readonly;

	spin_unlock(&priv->lock);

	err = apply_to_page_range(vma->vm_mm, vma->vm_start,
				  vma->vm_end - vma->vm_start,
				  find_grant_ptes, map);
	if (err) {
		printk(KERN_WARNING "find_grant_ptes() failure.\n");
		return err;
	}

	err = map_grant_pages(map);
	if (err) {
		printk(KERN_WARNING "map_grant_pages() failure.\n");
		return err;
	}

	map->is_mapped = 1;

	return 0;

unlock_out:
	spin_unlock(&priv->lock);
	return err;
}

static const struct file_operations gntdev_fops = {
	.owner = THIS_MODULE,
	.open = gntdev_open,
	.release = gntdev_release,
	.mmap = gntdev_mmap,
	.unlocked_ioctl = gntdev_ioctl
};

static struct miscdevice gntdev_miscdev = {
	.minor        = MISC_DYNAMIC_MINOR,
	.name         = "xen/gntdev",
	.fops         = &gntdev_fops,
};

/* ------------------------------------------------------------------ */

static int __init gntdev_init(void)
{
	int err;

	if (!xen_domain())
		return -ENODEV;

	err = misc_register(&gntdev_miscdev);
	if (err != 0) {
		printk(KERN_ERR "Could not register gntdev device\n");
		return err;
	}
	return 0;
}

static void __exit gntdev_exit(void)
{
	misc_deregister(&gntdev_miscdev);
}

module_init(gntdev_init);
module_exit(gntdev_exit);

/* ------------------------------------------------------------------ */
Commit	Line	Data
ab31523c GH	1	/******************************************************************************
	2	* gntdev.c
	3	*
	4	* Device for accessing (in user-space) pages that have been granted by other
	5	* domains.
	6	*
	7	* Copyright (c) 2006-2007, D G Murray.
	8	* (c) 2009 Gerd Hoffmann <[email protected]>
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	18	*/
	19
	20	#undef DEBUG
	21
	22	#include <linux/module.h>
	23	#include <linux/kernel.h>
	24	#include <linux/init.h>
	25	#include <linux/miscdevice.h>
	26	#include <linux/fs.h>
	27	#include <linux/mm.h>
	28	#include <linux/mman.h>
	29	#include <linux/mmu_notifier.h>
	30	#include <linux/types.h>
	31	#include <linux/uaccess.h>
	32	#include <linux/sched.h>
	33	#include <linux/spinlock.h>
	34	#include <linux/slab.h>
	35
	36	#include <xen/xen.h>
	37	#include <xen/grant_table.h>
	38	#include <xen/gntdev.h>
	39	#include <asm/xen/hypervisor.h>
	40	#include <asm/xen/hypercall.h>
	41	#include <asm/xen/page.h>
	42
	43	MODULE_LICENSE("GPL");
	44	MODULE_AUTHOR("Derek G. Murray <[email protected]>, "
	45	"Gerd Hoffmann <[email protected]>");
	46	MODULE_DESCRIPTION("User-space granted page access driver");
	47
	48	static int limit = 1024;
	49	module_param(limit, int, 0644);
	50	MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped at "
	51	"once by a gntdev instance");
	52
	53	struct gntdev_priv {
	54	struct list_head maps;
	55	uint32_t used;
	56	uint32_t limit;
	57	/* lock protects maps from concurrent changes */
	58	spinlock_t lock;
	59	struct mm_struct *mm;
	60	struct mmu_notifier mn;
	61	};
	62
	63	struct grant_map {
	64	struct list_head next;
65	struct gntdev_priv *priv;
66	struct vm_area_struct *vma;
67	int index;
68	int count;
69	int flags;
70	int is_mapped;
71	struct ioctl_gntdev_grant_ref *grants;
72	struct gnttab_map_grant_ref *map_ops;
73	struct gnttab_unmap_grant_ref *unmap_ops;
a12b4eb3	74	struct page **pages;
ab31523c GH	75	};
	76
	77	/* ------------------------------------------------------------------ */
	78
	79	static void gntdev_print_maps(struct gntdev_priv *priv,
	80	char *text, int text_index)
	81	{
	82	#ifdef DEBUG
	83	struct grant_map *map;
	84
	85	pr_debug("maps list (priv %p, usage %d/%d)\n",
	86	priv, priv->used, priv->limit);
	87
	88	list_for_each_entry(map, &priv->maps, next)
	89	pr_debug(" index %2d, count %2d %s\n",
	90	map->index, map->count,
	91	map->index == text_index && text ? text : "");
	92	#endif
	93	}
	94
	95	static struct grant_map gntdev_alloc_map(struct gntdev_priv priv, int count)
	96	{
	97	struct grant_map *add;
a12b4eb3	98	int i;
ab31523c GH	99
	100	add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
	101	if (NULL == add)
	102	return NULL;
	103
	104	add->grants = kzalloc(sizeof(add->grants[0]) * count, GFP_KERNEL);
	105	add->map_ops = kzalloc(sizeof(add->map_ops[0]) * count, GFP_KERNEL);
	106	add->unmap_ops = kzalloc(sizeof(add->unmap_ops[0]) * count, GFP_KERNEL);
a12b4eb3 SS	107	add->pages = kzalloc(sizeof(add->pages[0]) * count, GFP_KERNEL);
	108	if (NULL == add->grants \|\|
	109	NULL == add->map_ops \|\|
	110	NULL == add->unmap_ops \|\|
	111	NULL == add->pages)
ab31523c GH	112	goto err;
ab31523c GH	113
a12b4eb3 SS	114	for (i = 0; i < count; i++) {
	115	add->pages[i] = alloc_page(GFP_KERNEL \| __GFP_HIGHMEM);
	116	if (add->pages[i] == NULL)
	117	goto err;
	118	}
	119
ab31523c GH	120	add->index = 0;
	121	add->count = count;
	122	add->priv = priv;
	123
	124	if (add->count + priv->used > priv->limit)
	125	goto err;
	126
	127	return add;
	128
	129	err:
a12b4eb3 SS	130	if (add->pages)
	131	for (i = 0; i < count; i++) {
	132	if (add->pages[i])
	133	__free_page(add->pages[i]);
	134	}
	135	kfree(add->pages);
ab31523c GH	136	kfree(add->grants);
	137	kfree(add->map_ops);
	138	kfree(add->unmap_ops);
	139	kfree(add);
	140	return NULL;
	141	}
	142
	143	static void gntdev_add_map(struct gntdev_priv priv, struct grant_map add)
	144	{
	145	struct grant_map *map;
	146
	147	list_for_each_entry(map, &priv->maps, next) {
	148	if (add->index + add->count < map->index) {
	149	list_add_tail(&add->next, &map->next);
	150	goto done;
	151	}
	152	add->index = map->index + map->count;
	153	}
	154	list_add_tail(&add->next, &priv->maps);
	155
	156	done:
	157	priv->used += add->count;
	158	gntdev_print_maps(priv, "[new]", add->index);
	159	}
	160
	161	static struct grant_map gntdev_find_map_index(struct gntdev_priv priv,
	162	int index, int count)
	163	{
	164	struct grant_map *map;
	165
	166	list_for_each_entry(map, &priv->maps, next) {
	167	if (map->index != index)
	168	continue;
	169	if (map->count != count)
	170	continue;
	171	return map;
	172	}
	173	return NULL;
	174	}
	175
	176	static struct grant_map gntdev_find_map_vaddr(struct gntdev_priv priv,
	177	unsigned long vaddr)
	178	{
	179	struct grant_map *map;
	180
	181	list_for_each_entry(map, &priv->maps, next) {
	182	if (!map->vma)
	183	continue;
	184	if (vaddr < map->vma->vm_start)
	185	continue;
	186	if (vaddr >= map->vma->vm_end)
	187	continue;
	188	return map;
	189	}
	190	return NULL;
	191	}
	192
	193	static int gntdev_del_map(struct grant_map *map)
	194	{
	195	int i;
	196
	197	if (map->vma)
	198	return -EBUSY;
	199	for (i = 0; i < map->count; i++)
200	if (map->unmap_ops[i].handle)
201	return -EBUSY;
202
203	map->priv->used -= map->count;
204	list_del(&map->next);
205	return 0;
206	}
207
208	static void gntdev_free_map(struct grant_map *map)
209	{
a12b4eb3 SS	210	int i;
a12b4eb3 SS	211
ab31523c GH	212	if (!map)
ab31523c GH	213	return;
a12b4eb3 SS	214
	215	if (map->pages)
	216	for (i = 0; i < map->count; i++) {
	217	if (map->pages[i])
	218	__free_page(map->pages[i]);
	219	}
	220	kfree(map->pages);
ab31523c GH	221	kfree(map->grants);
	222	kfree(map->map_ops);
	223	kfree(map->unmap_ops);
	224	kfree(map);
	225	}
	226
	227	/* ------------------------------------------------------------------ */
	228
	229	static int find_grant_ptes(pte_t *pte, pgtable_t token,
	230	unsigned long addr, void *data)
	231	{
	232	struct grant_map *map = data;
	233	unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
	234	u64 pte_maddr;
	235
	236	BUG_ON(pgnr >= map->count);
ba5d1012 JF	237	pte_maddr = arbitrary_virt_to_machine(pte).maddr;
ba5d1012 JF	238
9329e760 IC	239	gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr,
9329e760 IC	240	GNTMAP_contains_pte \| map->flags,
ab31523c GH	241	map->grants[pgnr].ref,
ab31523c GH	242	map->grants[pgnr].domid);
9329e760 IC	243	gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr,
9329e760 IC	244	GNTMAP_contains_pte \| map->flags,
ab31523c GH	245	0 /* handle */);
	246	return 0;
	247	}
	248
	249	static int map_grant_pages(struct grant_map *map)
	250	{
	251	int i, err = 0;
	252
	253	pr_debug("map %d+%d\n", map->index, map->count);
a12b4eb3	254	err = gnttab_map_refs(map->map_ops, map->pages, map->count);
ab31523c GH	255	if (err)
	256	return err;
	257
	258	for (i = 0; i < map->count; i++) {
	259	if (map->map_ops[i].status)
	260	err = -EINVAL;
	261	map->unmap_ops[i].handle = map->map_ops[i].handle;
	262	}
	263	return err;
	264	}
	265
	266	static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
	267	{
	268	int i, err = 0;
	269
	270	pr_debug("map %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
a12b4eb3	271	err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages, pages);
ab31523c GH	272	if (err)
	273	return err;
	274
	275	for (i = 0; i < pages; i++) {
	276	if (map->unmap_ops[offset+i].status)
	277	err = -EINVAL;
	278	map->unmap_ops[offset+i].handle = 0;
	279	}
	280	return err;
	281	}
	282
	283	/* ------------------------------------------------------------------ */
	284
	285	static void gntdev_vma_close(struct vm_area_struct *vma)
	286	{
	287	struct grant_map *map = vma->vm_private_data;
	288
	289	pr_debug("close %p\n", vma);
	290	map->is_mapped = 0;
	291	map->vma = NULL;
	292	vma->vm_private_data = NULL;
	293	}
	294
	295	static int gntdev_vma_fault(struct vm_area_struct vma, struct vm_fault vmf)
	296	{
	297	pr_debug("vaddr %p, pgoff %ld (shouldn't happen)\n",
	298	vmf->virtual_address, vmf->pgoff);
	299	vmf->flags = VM_FAULT_ERROR;
	300	return 0;
	301	}
	302
	303	static struct vm_operations_struct gntdev_vmops = {
	304	.close = gntdev_vma_close,
	305	.fault = gntdev_vma_fault,
	306	};
	307
	308	/* ------------------------------------------------------------------ */
	309
	310	static void mn_invl_range_start(struct mmu_notifier *mn,
	311	struct mm_struct *mm,
	312	unsigned long start, unsigned long end)
	313	{
	314	struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
	315	struct grant_map *map;
	316	unsigned long mstart, mend;
	317	int err;
	318
	319	spin_lock(&priv->lock);
	320	list_for_each_entry(map, &priv->maps, next) {
	321	if (!map->vma)
	322	continue;
	323	if (!map->is_mapped)
	324	continue;
	325	if (map->vma->vm_start >= end)
	326	continue;
	327	if (map->vma->vm_end <= start)
	328	continue;
	329	mstart = max(start, map->vma->vm_start);
	330	mend = min(end, map->vma->vm_end);
	331	pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
	332	map->index, map->count,
	333	map->vma->vm_start, map->vma->vm_end,
	334	start, end, mstart, mend);
	335	err = unmap_grant_pages(map,
336	(mstart - map->vma->vm_start) >> PAGE_SHIFT,
337	(mend - mstart) >> PAGE_SHIFT);
338	WARN_ON(err);
339	}
340	spin_unlock(&priv->lock);
341	}
342
343	static void mn_invl_page(struct mmu_notifier *mn,
344	struct mm_struct *mm,
345	unsigned long address)
346	{
347	mn_invl_range_start(mn, mm, address, address + PAGE_SIZE);
348	}
349
350	static void mn_release(struct mmu_notifier *mn,
351	struct mm_struct *mm)
352	{
353	struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
354	struct grant_map *map;
355	int err;
356
357	spin_lock(&priv->lock);
358	list_for_each_entry(map, &priv->maps, next) {
359	if (!map->vma)
360	continue;
361	pr_debug("map %d+%d (%lx %lx)\n",
362	map->index, map->count,
363	map->vma->vm_start, map->vma->vm_end);
364	err = unmap_grant_pages(map, /* offset */ 0, map->count);
365	WARN_ON(err);
366	}
367	spin_unlock(&priv->lock);
368	}
369
370	struct mmu_notifier_ops gntdev_mmu_ops = {
371	.release = mn_release,
372	.invalidate_page = mn_invl_page,
373	.invalidate_range_start = mn_invl_range_start,
374	};
375
376	/* ------------------------------------------------------------------ */
377
378	static int gntdev_open(struct inode inode, struct file flip)
379	{
380	struct gntdev_priv *priv;
381	int ret = 0;
382
383	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
384	if (!priv)
385	return -ENOMEM;
386
387	INIT_LIST_HEAD(&priv->maps);
388	spin_lock_init(&priv->lock);
389	priv->limit = limit;
390
391	priv->mm = get_task_mm(current);
392	if (!priv->mm) {
393	kfree(priv);
394	return -ENOMEM;
395	}
396	priv->mn.ops = &gntdev_mmu_ops;
397	ret = mmu_notifier_register(&priv->mn, priv->mm);
398	mmput(priv->mm);
399
400	if (ret) {
401	kfree(priv);
402	return ret;
403	}
404
405	flip->private_data = priv;
406	pr_debug("priv %p\n", priv);
407
408	return 0;
409	}
410
411	static int gntdev_release(struct inode inode, struct file flip)
412	{
413	struct gntdev_priv *priv = flip->private_data;
414	struct grant_map *map;
415	int err;
416
417	pr_debug("priv %p\n", priv);
418
419	spin_lock(&priv->lock);
420	while (!list_empty(&priv->maps)) {
421	map = list_entry(priv->maps.next, struct grant_map, next);
422	err = gntdev_del_map(map);
423	if (WARN_ON(err))
424	gntdev_free_map(map);
425
426	}
427	spin_unlock(&priv->lock);
428
429	mmu_notifier_unregister(&priv->mn, priv->mm);
430	kfree(priv);
431	return 0;
432	}
433
434	static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
435	struct ioctl_gntdev_map_grant_ref __user *u)
436	{
437	struct ioctl_gntdev_map_grant_ref op;
438	struct grant_map *map;
439	int err;
440
441	if (copy_from_user(&op, u, sizeof(op)) != 0)
442	return -EFAULT;
443	pr_debug("priv %p, add %d\n", priv, op.count);
444	if (unlikely(op.count <= 0))
445	return -EINVAL;
446	if (unlikely(op.count > priv->limit))
447	return -EINVAL;
448
449	err = -ENOMEM;
450	map = gntdev_alloc_map(priv, op.count);
451	if (!map)
452	return err;
453	if (copy_from_user(map->grants, &u->refs,
454	sizeof(map->grants[0]) * op.count) != 0) {
455	gntdev_free_map(map);
456	return err;
457	}
458
459	spin_lock(&priv->lock);
460	gntdev_add_map(priv, map);
461	op.index = map->index << PAGE_SHIFT;
462	spin_unlock(&priv->lock);
463
464	if (copy_to_user(u, &op, sizeof(op)) != 0) {
465	spin_lock(&priv->lock);
466	gntdev_del_map(map);
467	spin_unlock(&priv->lock);
468	gntdev_free_map(map);
469	return err;
470	}
471	return 0;
472	}
473
474	static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
475	struct ioctl_gntdev_unmap_grant_ref __user *u)
476	{
477	struct ioctl_gntdev_unmap_grant_ref op;
478	struct grant_map *map;
479	int err = -ENOENT;
480
481	if (copy_from_user(&op, u, sizeof(op)) != 0)
482	return -EFAULT;
483	pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
484
485	spin_lock(&priv->lock);
486	map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
487	if (map)
488	err = gntdev_del_map(map);
489	spin_unlock(&priv->lock);
490	if (!err)
491	gntdev_free_map(map);
492	return err;
493	}
494
495	static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
496	struct ioctl_gntdev_get_offset_for_vaddr __user *u)
497	{
498	struct ioctl_gntdev_get_offset_for_vaddr op;
499	struct grant_map *map;
500
501	if (copy_from_user(&op, u, sizeof(op)) != 0)
502	return -EFAULT;
503	pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
504
505	spin_lock(&priv->lock);
506	map = gntdev_find_map_vaddr(priv, op.vaddr);
507	if (map == NULL \|\|
508	map->vma->vm_start != op.vaddr) {
509	spin_unlock(&priv->lock);
510	return -EINVAL;
511	}
512	op.offset = map->index << PAGE_SHIFT;
513	op.count = map->count;
514	spin_unlock(&priv->lock);
515
516	if (copy_to_user(u, &op, sizeof(op)) != 0)
517	return -EFAULT;
518	return 0;
519	}
520
521	static long gntdev_ioctl_set_max_grants(struct gntdev_priv *priv,
522	struct ioctl_gntdev_set_max_grants __user *u)
523	{
524	struct ioctl_gntdev_set_max_grants op;
525
526	if (copy_from_user(&op, u, sizeof(op)) != 0)
527	return -EFAULT;
528	pr_debug("priv %p, limit %d\n", priv, op.count);
529	if (op.count > limit)
530	return -E2BIG;
531
532	spin_lock(&priv->lock);
533	priv->limit = op.count;
534	spin_unlock(&priv->lock);
535	return 0;
536	}
537
538	static long gntdev_ioctl(struct file *flip,
539	unsigned int cmd, unsigned long arg)
540	{
541	struct gntdev_priv *priv = flip->private_data;
542	void __user ptr = (void __user )arg;
543
544	switch (cmd) {
545	case IOCTL_GNTDEV_MAP_GRANT_REF:
546	return gntdev_ioctl_map_grant_ref(priv, ptr);
547
548	case IOCTL_GNTDEV_UNMAP_GRANT_REF:
549	return gntdev_ioctl_unmap_grant_ref(priv, ptr);
550
551	case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
552	return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
553
554	case IOCTL_GNTDEV_SET_MAX_GRANTS:
555	return gntdev_ioctl_set_max_grants(priv, ptr);
556
557	default:
558	pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
559	return -ENOIOCTLCMD;
560	}
561
562	return 0;
563	}
564
565	static int gntdev_mmap(struct file flip, struct vm_area_struct vma)
566	{
567	struct gntdev_priv *priv = flip->private_data;
568	int index = vma->vm_pgoff;
569	int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
570	struct grant_map *map;
571	int err = -EINVAL;
572
573	if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
574	return -EINVAL;
575
576	pr_debug("map %d+%d at %lx (pgoff %lx)\n",
577	index, count, vma->vm_start, vma->vm_pgoff);
578
579	spin_lock(&priv->lock);
580	map = gntdev_find_map_index(priv, index, count);
581	if (!map)
582	goto unlock_out;
583	if (map->vma)
584	goto unlock_out;
585	if (priv->mm != vma->vm_mm) {
586	printk(KERN_WARNING "Huh? Other mm?\n");
587	goto unlock_out;
588	}
589
590	vma->vm_ops = &gntdev_vmops;
591
8d3eaea2	592	vma->vm_flags \|= VM_RESERVED\|VM_DONTCOPY\|VM_DONTEXPAND\|VM_PFNMAP;
ab31523c GH	593
	594	vma->vm_private_data = map;
	595	map->vma = vma;
	596
9329e760	597	map->flags = GNTMAP_host_map \| GNTMAP_application_map;
ab31523c GH	598	if (!(vma->vm_flags & VM_WRITE))
	599	map->flags \|= GNTMAP_readonly;
	600
f0a70c88 DDG	601	spin_unlock(&priv->lock);
f0a70c88 DDG	602
ab31523c GH	603	err = apply_to_page_range(vma->vm_mm, vma->vm_start,
	604	vma->vm_end - vma->vm_start,
	605	find_grant_ptes, map);
	606	if (err) {
	607	printk(KERN_WARNING "find_grant_ptes() failure.\n");
f0a70c88	608	return err;
ab31523c GH	609	}
	610
	611	err = map_grant_pages(map);
	612	if (err) {
	613	printk(KERN_WARNING "map_grant_pages() failure.\n");
f0a70c88	614	return err;
ab31523c	615	}
f0a70c88	616
ab31523c GH	617	map->is_mapped = 1;
ab31523c GH	618
f0a70c88 DDG	619	return 0;
f0a70c88 DDG	620
ab31523c GH	621	unlock_out:
	622	spin_unlock(&priv->lock);
	623	return err;
	624	}
	625
	626	static const struct file_operations gntdev_fops = {
	627	.owner = THIS_MODULE,
	628	.open = gntdev_open,
	629	.release = gntdev_release,
	630	.mmap = gntdev_mmap,
	631	.unlocked_ioctl = gntdev_ioctl
	632	};
	633
	634	static struct miscdevice gntdev_miscdev = {
	635	.minor = MISC_DYNAMIC_MINOR,
	636	.name = "xen/gntdev",
	637	.fops = &gntdev_fops,
	638	};
	639
	640	/* ------------------------------------------------------------------ */
	641
	642	static int __init gntdev_init(void)
	643	{
	644	int err;
	645
	646	if (!xen_domain())
	647	return -ENODEV;
	648
	649	err = misc_register(&gntdev_miscdev);
	650	if (err != 0) {
	651	printk(KERN_ERR "Could not register gntdev device\n");
	652	return err;
	653	}
	654	return 0;
	655	}
	656
	657	static void __exit gntdev_exit(void)
	658	{
	659	misc_deregister(&gntdev_miscdev);
	660	}
	661
	662	module_init(gntdev_init);
	663	module_exit(gntdev_exit);
	664
	665	/* ------------------------------------------------------------------ */