/******************************************************************************
* 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 <kraxel@redhat.com>
*
* 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
#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
#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 <linux/highmem.h>
#include <xen/xen.h>
#include <xen/grant_table.h>
#include <xen/balloon.h>
#include <xen/gntdev.h>
#include <xen/events.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/page.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
"Gerd Hoffmann <kraxel@redhat.com>");
MODULE_DESCRIPTION("User-space granted page access driver");
static int limit = 1024*1024;
module_param(limit, int, 0644);
MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by "
"the gntdev device");
static atomic_t pages_mapped = ATOMIC_INIT(0);
static int use_ptemod;
#define populate_freeable_maps use_ptemod
struct gntdev_priv {
/* maps with visible offsets in the file descriptor */
struct list_head maps;
/* maps that are not visible; will be freed on munmap.
* Only populated if populate_freeable_maps == 1 */
struct list_head freeable_maps;
/* lock protects maps and freeable_maps */
struct mutex lock;
struct mm_struct *mm;
struct mmu_notifier mn;
};
struct unmap_notify {
int flags;
/* Address relative to the start of the grant_map */
int addr;
int event;
};
struct grant_map {
struct list_head next;
struct vm_area_struct *vma;
int index;
int count;
int flags;
atomic_t users;
struct unmap_notify notify;
struct ioctl_gntdev_grant_ref *grants;
struct gnttab_map_grant_ref *map_ops;
struct gnttab_unmap_grant_ref *unmap_ops;
struct gnttab_map_grant_ref *kmap_ops;
struct gnttab_unmap_grant_ref *kunmap_ops;
struct page **pages;
unsigned long pages_vm_start;
};
static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
/* ------------------------------------------------------------------ */
static void gntdev_print_maps(struct gntdev_priv *priv,
char *text, int text_index)
{
#ifdef DEBUG
struct grant_map *map;
pr_debug("%s: maps list (priv %p)\n", __func__, priv);
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 void gntdev_free_map(struct grant_map *map)
{
if (map == NULL)
return;
if (map->pages)
gnttab_free_pages(map->count, map->pages);
kfree(map->pages);
kfree(map->grants);
kfree(map->map_ops);
kfree(map->unmap_ops);
kfree(map->kmap_ops);
kfree(map->kunmap_ops);
kfree(map);
}
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 = kcalloc(count, sizeof(add->grants[0]), GFP_KERNEL);
add->map_ops = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL);
add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL);
add->kmap_ops = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL);
add->kunmap_ops = kcalloc(count, sizeof(add->kunmap_ops[0]), GFP_KERNEL);
add->pages = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
if (NULL == add->grants ||
NULL == add->map_ops ||
NULL == add->unmap_ops ||
NULL == add->kmap_ops ||
NULL == add->kunmap_ops ||
NULL == add->pages)
goto err;
if (gnttab_alloc_pages(count, add->pages))
goto err;
for (i = 0; i < count; i++) {
add->map_ops[i].handle = -1;
add->unmap_ops[i].handle