linux/drivers/xen/gntdev.c
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   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 <kraxel@redhat.com>
   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#include <linux/highmem.h>
  36
  37#include <xen/xen.h>
  38#include <xen/grant_table.h>
  39#include <xen/balloon.h>
  40#include <xen/gntdev.h>
  41#include <xen/events.h>
  42#include <asm/xen/hypervisor.h>
  43#include <asm/xen/hypercall.h>
  44#include <asm/xen/page.h>
  45
  46MODULE_LICENSE("GPL");
  47MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
  48              "Gerd Hoffmann <kraxel@redhat.com>");
  49MODULE_DESCRIPTION("User-space granted page access driver");
  50
  51static int limit = 1024*1024;
  52module_param(limit, int, 0644);
  53MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by "
  54                "the gntdev device");
  55
  56static atomic_t pages_mapped = ATOMIC_INIT(0);
  57
  58static int use_ptemod;
  59
  60struct gntdev_priv {
  61        struct list_head maps;
  62        /* lock protects maps from concurrent changes */
  63        spinlock_t lock;
  64        struct mm_struct *mm;
  65        struct mmu_notifier mn;
  66};
  67
  68struct unmap_notify {
  69        int flags;
  70        /* Address relative to the start of the grant_map */
  71        int addr;
  72        int event;
  73};
  74
  75struct grant_map {
  76        struct list_head next;
  77        struct vm_area_struct *vma;
  78        int index;
  79        int count;
  80        int flags;
  81        atomic_t users;
  82        struct unmap_notify notify;
  83        struct ioctl_gntdev_grant_ref *grants;
  84        struct gnttab_map_grant_ref   *map_ops;
  85        struct gnttab_unmap_grant_ref *unmap_ops;
  86        struct gnttab_map_grant_ref   *kmap_ops;
  87        struct page **pages;
  88};
  89
  90static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
  91
  92/* ------------------------------------------------------------------ */
  93
  94static void gntdev_print_maps(struct gntdev_priv *priv,
  95                              char *text, int text_index)
  96{
  97#ifdef DEBUG
  98        struct grant_map *map;
  99
 100        pr_debug("%s: maps list (priv %p)\n", __func__, priv);
 101        list_for_each_entry(map, &priv->maps, next)
 102                pr_debug("  index %2d, count %2d %s\n",
 103                       map->index, map->count,
 104                       map->index == text_index && text ? text : "");
 105#endif
 106}
 107
 108static void gntdev_free_map(struct grant_map *map)
 109{
 110        if (map == NULL)
 111                return;
 112
 113        if (map->pages)
 114                free_xenballooned_pages(map->count, map->pages);
 115        kfree(map->pages);
 116        kfree(map->grants);
 117        kfree(map->map_ops);
 118        kfree(map->unmap_ops);
 119        kfree(map->kmap_ops);
 120        kfree(map);
 121}
 122
 123static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
 124{
 125        struct grant_map *add;
 126        int i;
 127
 128        add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
 129        if (NULL == add)
 130                return NULL;
 131
 132        add->grants    = kcalloc(count, sizeof(add->grants[0]), GFP_KERNEL);
 133        add->map_ops   = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL);
 134        add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL);
 135        add->kmap_ops  = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL);
 136        add->pages     = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
 137        if (NULL == add->grants    ||
 138            NULL == add->map_ops   ||
 139            NULL == add->unmap_ops ||
 140            NULL == add->kmap_ops  ||
 141            NULL == add->pages)
 142                goto err;
 143
 144        if (alloc_xenballooned_pages(count, add->pages, false /* lowmem */))
 145                goto err;
 146
 147        for (i = 0; i < count; i++) {
 148                add->map_ops[i].handle = -1;
 149                add->unmap_ops[i].handle = -1;
 150                add->kmap_ops[i].handle = -1;
 151        }
 152
 153        add->index = 0;
 154        add->count = count;
 155        atomic_set(&add->users, 1);
 156
 157        return add;
 158
 159err:
 160        gntdev_free_map(add);
 161        return NULL;
 162}
 163
 164static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
 165{
 166        struct grant_map *map;
 167
 168        list_for_each_entry(map, &priv->maps, next) {
 169                if (add->index + add->count < map->index) {
 170                        list_add_tail(&add->next, &map->next);
 171                        goto done;
 172                }
 173                add->index = map->index + map->count;
 174        }
 175        list_add_tail(&add->next, &priv->maps);
 176
 177done:
 178        gntdev_print_maps(priv, "[new]", add->index);
 179}
 180
 181static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
 182                int index, int count)
 183{
 184        struct grant_map *map;
 185
 186        list_for_each_entry(map, &priv->maps, next) {
 187                if (map->index != index)
 188                        continue;
 189                if (count && map->count != count)
 190                        continue;
 191                return map;
 192        }
 193        return NULL;
 194}
 195
 196static void gntdev_put_map(struct grant_map *map)
 197{
 198        if (!map)
 199                return;
 200
 201        if (!atomic_dec_and_test(&map->users))
 202                return;
 203
 204        atomic_sub(map->count, &pages_mapped);
 205
 206        if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
 207                notify_remote_via_evtchn(map->notify.event);
 208                evtchn_put(map->notify.event);
 209        }
 210
 211        if (map->pages && !use_ptemod)
 212                unmap_grant_pages(map, 0, map->count);
 213        gntdev_free_map(map);
 214}
 215
 216/* ------------------------------------------------------------------ */
 217
 218static int find_grant_ptes(pte_t *pte, pgtable_t token,
 219                unsigned long addr, void *data)
 220{
 221        struct grant_map *map = data;
 222        unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
 223        int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
 224        u64 pte_maddr;
 225
 226        BUG_ON(pgnr >= map->count);
 227        pte_maddr = arbitrary_virt_to_machine(pte).maddr;
 228
 229        gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
 230                          map->grants[pgnr].ref,
 231                          map->grants[pgnr].domid);
 232        gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
 233                            -1 /* handle */);
 234        return 0;
 235}
 236
 237static int map_grant_pages(struct grant_map *map)
 238{
 239        int i, err = 0;
 240
 241        if (!use_ptemod) {
 242                /* Note: it could already be mapped */
 243                if (map->map_ops[0].handle != -1)
 244                        return 0;
 245                for (i = 0; i < map->count; i++) {
 246                        unsigned long addr = (unsigned long)
 247                                pfn_to_kaddr(page_to_pfn(map->pages[i]));
 248                        gnttab_set_map_op(&map->map_ops[i], addr, map->flags,
 249                                map->grants[i].ref,
 250                                map->grants[i].domid);
 251                        gnttab_set_unmap_op(&map->unmap_ops[i], addr,
 252                                map->flags, -1 /* handle */);
 253                }
 254        } else {
 255                /*
 256                 * Setup the map_ops corresponding to the pte entries pointing
 257                 * to the kernel linear addresses of the struct pages.
 258                 * These ptes are completely different from the user ptes dealt
 259                 * with find_grant_ptes.
 260                 */
 261                for (i = 0; i < map->count; i++) {
 262                        unsigned level;
 263                        unsigned long address = (unsigned long)
 264                                pfn_to_kaddr(page_to_pfn(map->pages[i]));
 265                        pte_t *ptep;
 266                        u64 pte_maddr = 0;
 267                        BUG_ON(PageHighMem(map->pages[i]));
 268
 269                        ptep = lookup_address(address, &level);
 270                        pte_maddr = arbitrary_virt_to_machine(ptep).maddr;
 271                        gnttab_set_map_op(&map->kmap_ops[i], pte_maddr,
 272                                map->flags |
 273                                GNTMAP_host_map |
 274                                GNTMAP_contains_pte,
 275                                map->grants[i].ref,
 276                                map->grants[i].domid);
 277                }
 278        }
 279
 280        pr_debug("map %d+%d\n", map->index, map->count);
 281        err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
 282                        map->pages, map->count);
 283        if (err)
 284                return err;
 285
 286        for (i = 0; i < map->count; i++) {
 287                if (map->map_ops[i].status)
 288                        err = -EINVAL;
 289                else {
 290                        BUG_ON(map->map_ops[i].handle == -1);
 291                        map->unmap_ops[i].handle = map->map_ops[i].handle;
 292                        pr_debug("map handle=%d\n", map->map_ops[i].handle);
 293                }
 294        }
 295        return err;
 296}
 297
 298static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
 299{
 300        int i, err = 0;
 301
 302        if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
 303                int pgno = (map->notify.addr >> PAGE_SHIFT);
 304                if (pgno >= offset && pgno < offset + pages && use_ptemod) {
 305                        void __user *tmp = (void __user *)
 306                                map->vma->vm_start + map->notify.addr;
 307                        err = copy_to_user(tmp, &err, 1);
 308                        if (err)
 309                                return -EFAULT;
 310                        map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
 311                } else if (pgno >= offset && pgno < offset + pages) {
 312                        uint8_t *tmp = kmap(map->pages[pgno]);
 313                        tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
 314                        kunmap(map->pages[pgno]);
 315                        map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
 316                }
 317        }
 318
 319        err = gnttab_unmap_refs(map->unmap_ops + offset,
 320                        use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset,
 321                        pages);
 322        if (err)
 323                return err;
 324
 325        for (i = 0; i < pages; i++) {
 326                if (map->unmap_ops[offset+i].status)
 327                        err = -EINVAL;
 328                pr_debug("unmap handle=%d st=%d\n",
 329                        map->unmap_ops[offset+i].handle,
 330                        map->unmap_ops[offset+i].status);
 331                map->unmap_ops[offset+i].handle = -1;
 332        }
 333        return err;
 334}
 335
 336static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
 337{
 338        int range, err = 0;
 339
 340        pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
 341
 342        /* It is possible the requested range will have a "hole" where we
 343         * already unmapped some of the grants. Only unmap valid ranges.
 344         */
 345        while (pages && !err) {
 346                while (pages && map->unmap_ops[offset].handle == -1) {
 347                        offset++;
 348                        pages--;
 349                }
 350                range = 0;
 351                while (range < pages) {
 352                        if (map->unmap_ops[offset+range].handle == -1) {
 353                                range--;
 354                                break;
 355                        }
 356                        range++;
 357                }
 358                err = __unmap_grant_pages(map, offset, range);
 359                offset += range;
 360                pages -= range;
 361        }
 362
 363        return err;
 364}
 365
 366/* ------------------------------------------------------------------ */
 367
 368static void gntdev_vma_open(struct vm_area_struct *vma)
 369{
 370        struct grant_map *map = vma->vm_private_data;
 371
 372        pr_debug("gntdev_vma_open %p\n", vma);
 373        atomic_inc(&map->users);
 374}
 375
 376static void gntdev_vma_close(struct vm_area_struct *vma)
 377{
 378        struct grant_map *map = vma->vm_private_data;
 379
 380        pr_debug("gntdev_vma_close %p\n", vma);
 381        map->vma = NULL;
 382        vma->vm_private_data = NULL;
 383        gntdev_put_map(map);
 384}
 385
 386static struct vm_operations_struct gntdev_vmops = {
 387        .open = gntdev_vma_open,
 388        .close = gntdev_vma_close,
 389};
 390
 391/* ------------------------------------------------------------------ */
 392
 393static void mn_invl_range_start(struct mmu_notifier *mn,
 394                                struct mm_struct *mm,
 395                                unsigned long start, unsigned long end)
 396{
 397        struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
 398        struct grant_map *map;
 399        unsigned long mstart, mend;
 400        int err;
 401
 402        spin_lock(&priv->lock);
 403        list_for_each_entry(map, &priv->maps, next) {
 404                if (!map->vma)
 405                        continue;
 406                if (map->vma->vm_start >= end)
 407                        continue;
 408                if (map->vma->vm_end <= start)
 409                        continue;
 410                mstart = max(start, map->vma->vm_start);
 411                mend   = min(end,   map->vma->vm_end);
 412                pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
 413                                map->index, map->count,
 414                                map->vma->vm_start, map->vma->vm_end,
 415                                start, end, mstart, mend);
 416                err = unmap_grant_pages(map,
 417                                        (mstart - map->vma->vm_start) >> PAGE_SHIFT,
 418                                        (mend - mstart) >> PAGE_SHIFT);
 419                WARN_ON(err);
 420        }
 421        spin_unlock(&priv->lock);
 422}
 423
 424static void mn_invl_page(struct mmu_notifier *mn,
 425                         struct mm_struct *mm,
 426                         unsigned long address)
 427{
 428        mn_invl_range_start(mn, mm, address, address + PAGE_SIZE);
 429}
 430
 431static void mn_release(struct mmu_notifier *mn,
 432                       struct mm_struct *mm)
 433{
 434        struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
 435        struct grant_map *map;
 436        int err;
 437
 438        spin_lock(&priv->lock);
 439        list_for_each_entry(map, &priv->maps, next) {
 440                if (!map->vma)
 441                        continue;
 442                pr_debug("map %d+%d (%lx %lx)\n",
 443                                map->index, map->count,
 444                                map->vma->vm_start, map->vma->vm_end);
 445                err = unmap_grant_pages(map, /* offset */ 0, map->count);
 446                WARN_ON(err);
 447        }
 448        spin_unlock(&priv->lock);
 449}
 450
 451static struct mmu_notifier_ops gntdev_mmu_ops = {
 452        .release                = mn_release,
 453        .invalidate_page        = mn_invl_page,
 454        .invalidate_range_start = mn_invl_range_start,
 455};
 456
 457/* ------------------------------------------------------------------ */
 458
 459static int gntdev_open(struct inode *inode, struct file *flip)
 460{
 461        struct gntdev_priv *priv;
 462        int ret = 0;
 463
 464        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 465        if (!priv)
 466                return -ENOMEM;
 467
 468        INIT_LIST_HEAD(&priv->maps);
 469        spin_lock_init(&priv->lock);
 470
 471        if (use_ptemod) {
 472                priv->mm = get_task_mm(current);
 473                if (!priv->mm) {
 474                        kfree(priv);
 475                        return -ENOMEM;
 476                }
 477                priv->mn.ops = &gntdev_mmu_ops;
 478                ret = mmu_notifier_register(&priv->mn, priv->mm);
 479                mmput(priv->mm);
 480        }
 481
 482        if (ret) {
 483                kfree(priv);
 484                return ret;
 485        }
 486
 487        flip->private_data = priv;
 488        pr_debug("priv %p\n", priv);
 489
 490        return 0;
 491}
 492
 493static int gntdev_release(struct inode *inode, struct file *flip)
 494{
 495        struct gntdev_priv *priv = flip->private_data;
 496        struct grant_map *map;
 497
 498        pr_debug("priv %p\n", priv);
 499
 500        while (!list_empty(&priv->maps)) {
 501                map = list_entry(priv->maps.next, struct grant_map, next);
 502                list_del(&map->next);
 503                gntdev_put_map(map);
 504        }
 505
 506        if (use_ptemod)
 507                mmu_notifier_unregister(&priv->mn, priv->mm);
 508        kfree(priv);
 509        return 0;
 510}
 511
 512static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
 513                                       struct ioctl_gntdev_map_grant_ref __user *u)
 514{
 515        struct ioctl_gntdev_map_grant_ref op;
 516        struct grant_map *map;
 517        int err;
 518
 519        if (copy_from_user(&op, u, sizeof(op)) != 0)
 520                return -EFAULT;
 521        pr_debug("priv %p, add %d\n", priv, op.count);
 522        if (unlikely(op.count <= 0))
 523                return -EINVAL;
 524
 525        err = -ENOMEM;
 526        map = gntdev_alloc_map(priv, op.count);
 527        if (!map)
 528                return err;
 529
 530        if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) {
 531                pr_debug("can't map: over limit\n");
 532                gntdev_put_map(map);
 533                return err;
 534        }
 535
 536        if (copy_from_user(map->grants, &u->refs,
 537                           sizeof(map->grants[0]) * op.count) != 0) {
 538                gntdev_put_map(map);
 539                return err;
 540        }
 541
 542        spin_lock(&priv->lock);
 543        gntdev_add_map(priv, map);
 544        op.index = map->index << PAGE_SHIFT;
 545        spin_unlock(&priv->lock);
 546
 547        if (copy_to_user(u, &op, sizeof(op)) != 0)
 548                return -EFAULT;
 549
 550        return 0;
 551}
 552
 553static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
 554                                         struct ioctl_gntdev_unmap_grant_ref __user *u)
 555{
 556        struct ioctl_gntdev_unmap_grant_ref op;
 557        struct grant_map *map;
 558        int err = -ENOENT;
 559
 560        if (copy_from_user(&op, u, sizeof(op)) != 0)
 561                return -EFAULT;
 562        pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
 563
 564        spin_lock(&priv->lock);
 565        map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
 566        if (map) {
 567                list_del(&map->next);
 568                err = 0;
 569        }
 570        spin_unlock(&priv->lock);
 571        if (map)
 572                gntdev_put_map(map);
 573        return err;
 574}
 575
 576static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
 577                                              struct ioctl_gntdev_get_offset_for_vaddr __user *u)
 578{
 579        struct ioctl_gntdev_get_offset_for_vaddr op;
 580        struct vm_area_struct *vma;
 581        struct grant_map *map;
 582
 583        if (copy_from_user(&op, u, sizeof(op)) != 0)
 584                return -EFAULT;
 585        pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
 586
 587        vma = find_vma(current->mm, op.vaddr);
 588        if (!vma || vma->vm_ops != &gntdev_vmops)
 589                return -EINVAL;
 590
 591        map = vma->vm_private_data;
 592        if (!map)
 593                return -EINVAL;
 594
 595        op.offset = map->index << PAGE_SHIFT;
 596        op.count = map->count;
 597
 598        if (copy_to_user(u, &op, sizeof(op)) != 0)
 599                return -EFAULT;
 600        return 0;
 601}
 602
 603static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
 604{
 605        struct ioctl_gntdev_unmap_notify op;
 606        struct grant_map *map;
 607        int rc;
 608        int out_flags;
 609        unsigned int out_event;
 610
 611        if (copy_from_user(&op, u, sizeof(op)))
 612                return -EFAULT;
 613
 614        if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
 615                return -EINVAL;
 616
 617        /* We need to grab a reference to the event channel we are going to use
 618         * to send the notify before releasing the reference we may already have
 619         * (if someone has called this ioctl twice). This is required so that
 620         * it is possible to change the clear_byte part of the notification
 621         * without disturbing the event channel part, which may now be the last
 622         * reference to that event channel.
 623         */
 624        if (op.action & UNMAP_NOTIFY_SEND_EVENT) {
 625                if (evtchn_get(op.event_channel_port))
 626                        return -EINVAL;
 627        }
 628
 629        out_flags = op.action;
 630        out_event = op.event_channel_port;
 631
 632        spin_lock(&priv->lock);
 633
 634        list_for_each_entry(map, &priv->maps, next) {
 635                uint64_t begin = map->index << PAGE_SHIFT;
 636                uint64_t end = (map->index + map->count) << PAGE_SHIFT;
 637                if (op.index >= begin && op.index < end)
 638                        goto found;
 639        }
 640        rc = -ENOENT;
 641        goto unlock_out;
 642
 643 found:
 644        if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
 645                        (map->flags & GNTMAP_readonly)) {
 646                rc = -EINVAL;
 647                goto unlock_out;
 648        }
 649
 650        out_flags = map->notify.flags;
 651        out_event = map->notify.event;
 652
 653        map->notify.flags = op.action;
 654        map->notify.addr = op.index - (map->index << PAGE_SHIFT);
 655        map->notify.event = op.event_channel_port;
 656
 657        rc = 0;
 658
 659 unlock_out:
 660        spin_unlock(&priv->lock);
 661
 662        /* Drop the reference to the event channel we did not save in the map */
 663        if (out_flags & UNMAP_NOTIFY_SEND_EVENT)
 664                evtchn_put(out_event);
 665
 666        return rc;
 667}
 668
 669static long gntdev_ioctl(struct file *flip,
 670                         unsigned int cmd, unsigned long arg)
 671{
 672        struct gntdev_priv *priv = flip->private_data;
 673        void __user *ptr = (void __user *)arg;
 674
 675        switch (cmd) {
 676        case IOCTL_GNTDEV_MAP_GRANT_REF:
 677                return gntdev_ioctl_map_grant_ref(priv, ptr);
 678
 679        case IOCTL_GNTDEV_UNMAP_GRANT_REF:
 680                return gntdev_ioctl_unmap_grant_ref(priv, ptr);
 681
 682        case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
 683                return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
 684
 685        case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
 686                return gntdev_ioctl_notify(priv, ptr);
 687
 688        default:
 689                pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
 690                return -ENOIOCTLCMD;
 691        }
 692
 693        return 0;
 694}
 695
 696static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
 697{
 698        struct gntdev_priv *priv = flip->private_data;
 699        int index = vma->vm_pgoff;
 700        int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 701        struct grant_map *map;
 702        int i, err = -EINVAL;
 703
 704        if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
 705                return -EINVAL;
 706
 707        pr_debug("map %d+%d at %lx (pgoff %lx)\n",
 708                        index, count, vma->vm_start, vma->vm_pgoff);
 709
 710        spin_lock(&priv->lock);
 711        map = gntdev_find_map_index(priv, index, count);
 712        if (!map)
 713                goto unlock_out;
 714        if (use_ptemod && map->vma)
 715                goto unlock_out;
 716        if (use_ptemod && priv->mm != vma->vm_mm) {
 717                printk(KERN_WARNING "Huh? Other mm?\n");
 718                goto unlock_out;
 719        }
 720
 721        atomic_inc(&map->users);
 722
 723        vma->vm_ops = &gntdev_vmops;
 724
 725        vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 726
 727        if (use_ptemod)
 728                vma->vm_flags |= VM_DONTCOPY;
 729
 730        vma->vm_private_data = map;
 731
 732        if (use_ptemod)
 733                map->vma = vma;
 734
 735        if (map->flags) {
 736                if ((vma->vm_flags & VM_WRITE) &&
 737                                (map->flags & GNTMAP_readonly))
 738                        goto out_unlock_put;
 739        } else {
 740                map->flags = GNTMAP_host_map;
 741                if (!(vma->vm_flags & VM_WRITE))
 742                        map->flags |= GNTMAP_readonly;
 743        }
 744
 745        spin_unlock(&priv->lock);
 746
 747        if (use_ptemod) {
 748                err = apply_to_page_range(vma->vm_mm, vma->vm_start,
 749                                          vma->vm_end - vma->vm_start,
 750                                          find_grant_ptes, map);
 751                if (err) {
 752                        printk(KERN_WARNING "find_grant_ptes() failure.\n");
 753                        goto out_put_map;
 754                }
 755        }
 756
 757        err = map_grant_pages(map);
 758        if (err)
 759                goto out_put_map;
 760
 761        if (!use_ptemod) {
 762                for (i = 0; i < count; i++) {
 763                        err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE,
 764                                map->pages[i]);
 765                        if (err)
 766                                goto out_put_map;
 767                }
 768        }
 769
 770        return 0;
 771
 772unlock_out:
 773        spin_unlock(&priv->lock);
 774        return err;
 775
 776out_unlock_put:
 777        spin_unlock(&priv->lock);
 778out_put_map:
 779        if (use_ptemod)
 780                map->vma = NULL;
 781        gntdev_put_map(map);
 782        return err;
 783}
 784
 785static const struct file_operations gntdev_fops = {
 786        .owner = THIS_MODULE,
 787        .open = gntdev_open,
 788        .release = gntdev_release,
 789        .mmap = gntdev_mmap,
 790        .unlocked_ioctl = gntdev_ioctl
 791};
 792
 793static struct miscdevice gntdev_miscdev = {
 794        .minor        = MISC_DYNAMIC_MINOR,
 795        .name         = "xen/gntdev",
 796        .fops         = &gntdev_fops,
 797};
 798
 799/* ------------------------------------------------------------------ */
 800
 801static int __init gntdev_init(void)
 802{
 803        int err;
 804
 805        if (!xen_domain())
 806                return -ENODEV;
 807
 808        use_ptemod = xen_pv_domain();
 809
 810        err = misc_register(&gntdev_miscdev);
 811        if (err != 0) {
 812                printk(KERN_ERR "Could not register gntdev device\n");
 813                return err;
 814        }
 815        return 0;
 816}
 817
 818static void __exit gntdev_exit(void)
 819{
 820        misc_deregister(&gntdev_miscdev);
 821}
 822
 823module_init(gntdev_init);
 824module_exit(gntdev_exit);
 825
 826/* ------------------------------------------------------------------ */
 827
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