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