1176 lines · c
1/******************************************************************************2 * gntdev.c3 *4 * Device for accessing (in user-space) pages that have been granted by other5 * domains.6 *7 * Copyright (c) 2006-2007, D G Murray.8 * (c) 2009 Gerd Hoffmann <kraxel@redhat.com>9 * (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.10 *11 * This program is distributed in the hope that it will be useful,12 * but WITHOUT ANY WARRANTY; without even the implied warranty of13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the14 * GNU General Public License for more details.15 *16 * You should have received a copy of the GNU General Public License17 * along with this program; if not, write to the Free Software18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA19 */20 21#undef DEBUG22 23#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt24 25#include <linux/dma-mapping.h>26#include <linux/module.h>27#include <linux/kernel.h>28#include <linux/init.h>29#include <linux/miscdevice.h>30#include <linux/fs.h>31#include <linux/uaccess.h>32#include <linux/sched.h>33#include <linux/sched/mm.h>34#include <linux/spinlock.h>35#include <linux/slab.h>36#include <linux/highmem.h>37#include <linux/refcount.h>38#include <linux/workqueue.h>39 40#include <xen/xen.h>41#include <xen/grant_table.h>42#include <xen/balloon.h>43#include <xen/gntdev.h>44#include <xen/events.h>45#include <xen/page.h>46#include <asm/xen/hypervisor.h>47#include <asm/xen/hypercall.h>48 49#include "gntdev-common.h"50#ifdef CONFIG_XEN_GNTDEV_DMABUF51#include "gntdev-dmabuf.h"52#endif53 54MODULE_LICENSE("GPL");55MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "56 "Gerd Hoffmann <kraxel@redhat.com>");57MODULE_DESCRIPTION("User-space granted page access driver");58 59static unsigned int limit = 64*1024;60module_param(limit, uint, 0644);61MODULE_PARM_DESC(limit,62 "Maximum number of grants that may be mapped by one mapping request");63 64/* True in PV mode, false otherwise */65static int use_ptemod;66 67static void unmap_grant_pages(struct gntdev_grant_map *map,68 int offset, int pages);69 70static struct miscdevice gntdev_miscdev;71 72/* ------------------------------------------------------------------ */73 74bool gntdev_test_page_count(unsigned int count)75{76 return !count || count > limit;77}78 79static void gntdev_print_maps(struct gntdev_priv *priv,80 char *text, int text_index)81{82#ifdef DEBUG83 struct gntdev_grant_map *map;84 85 pr_debug("%s: maps list (priv %p)\n", __func__, priv);86 list_for_each_entry(map, &priv->maps, next)87 pr_debug(" index %2d, count %2d %s\n",88 map->index, map->count,89 map->index == text_index && text ? text : "");90#endif91}92 93static void gntdev_free_map(struct gntdev_grant_map *map)94{95 if (map == NULL)96 return;97 98#ifdef CONFIG_XEN_GRANT_DMA_ALLOC99 if (map->dma_vaddr) {100 struct gnttab_dma_alloc_args args;101 102 args.dev = map->dma_dev;103 args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT);104 args.nr_pages = map->count;105 args.pages = map->pages;106 args.frames = map->frames;107 args.vaddr = map->dma_vaddr;108 args.dev_bus_addr = map->dma_bus_addr;109 110 gnttab_dma_free_pages(&args);111 } else112#endif113 if (map->pages)114 gnttab_free_pages(map->count, map->pages);115 116#ifdef CONFIG_XEN_GRANT_DMA_ALLOC117 kvfree(map->frames);118#endif119 kvfree(map->pages);120 kvfree(map->grants);121 kvfree(map->map_ops);122 kvfree(map->unmap_ops);123 kvfree(map->kmap_ops);124 kvfree(map->kunmap_ops);125 kvfree(map->being_removed);126 kfree(map);127}128 129struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,130 int dma_flags)131{132 struct gntdev_grant_map *add;133 int i;134 135 add = kzalloc(sizeof(*add), GFP_KERNEL);136 if (NULL == add)137 return NULL;138 139 add->grants = kvmalloc_array(count, sizeof(add->grants[0]),140 GFP_KERNEL);141 add->map_ops = kvmalloc_array(count, sizeof(add->map_ops[0]),142 GFP_KERNEL);143 add->unmap_ops = kvmalloc_array(count, sizeof(add->unmap_ops[0]),144 GFP_KERNEL);145 add->pages = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);146 add->being_removed =147 kvcalloc(count, sizeof(add->being_removed[0]), GFP_KERNEL);148 if (NULL == add->grants ||149 NULL == add->map_ops ||150 NULL == add->unmap_ops ||151 NULL == add->pages ||152 NULL == add->being_removed)153 goto err;154 if (use_ptemod) {155 add->kmap_ops = kvmalloc_array(count, sizeof(add->kmap_ops[0]),156 GFP_KERNEL);157 add->kunmap_ops = kvmalloc_array(count, sizeof(add->kunmap_ops[0]),158 GFP_KERNEL);159 if (NULL == add->kmap_ops || NULL == add->kunmap_ops)160 goto err;161 }162 163#ifdef CONFIG_XEN_GRANT_DMA_ALLOC164 add->dma_flags = dma_flags;165 166 /*167 * Check if this mapping is requested to be backed168 * by a DMA buffer.169 */170 if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) {171 struct gnttab_dma_alloc_args args;172 173 add->frames = kvcalloc(count, sizeof(add->frames[0]),174 GFP_KERNEL);175 if (!add->frames)176 goto err;177 178 /* Remember the device, so we can free DMA memory. */179 add->dma_dev = priv->dma_dev;180 181 args.dev = priv->dma_dev;182 args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT);183 args.nr_pages = count;184 args.pages = add->pages;185 args.frames = add->frames;186 187 if (gnttab_dma_alloc_pages(&args))188 goto err;189 190 add->dma_vaddr = args.vaddr;191 add->dma_bus_addr = args.dev_bus_addr;192 } else193#endif194 if (gnttab_alloc_pages(count, add->pages))195 goto err;196 197 for (i = 0; i < count; i++) {198 add->grants[i].domid = DOMID_INVALID;199 add->grants[i].ref = INVALID_GRANT_REF;200 add->map_ops[i].handle = INVALID_GRANT_HANDLE;201 add->unmap_ops[i].handle = INVALID_GRANT_HANDLE;202 if (use_ptemod) {203 add->kmap_ops[i].handle = INVALID_GRANT_HANDLE;204 add->kunmap_ops[i].handle = INVALID_GRANT_HANDLE;205 }206 }207 208 add->index = 0;209 add->count = count;210 refcount_set(&add->users, 1);211 212 return add;213 214err:215 gntdev_free_map(add);216 return NULL;217}218 219void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add)220{221 struct gntdev_grant_map *map;222 223 list_for_each_entry(map, &priv->maps, next) {224 if (add->index + add->count < map->index) {225 list_add_tail(&add->next, &map->next);226 goto done;227 }228 add->index = map->index + map->count;229 }230 list_add_tail(&add->next, &priv->maps);231 232done:233 gntdev_print_maps(priv, "[new]", add->index);234}235 236static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv,237 int index, int count)238{239 struct gntdev_grant_map *map;240 241 list_for_each_entry(map, &priv->maps, next) {242 if (map->index != index)243 continue;244 if (count && map->count != count)245 continue;246 return map;247 }248 return NULL;249}250 251void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map)252{253 if (!map)254 return;255 256 if (!refcount_dec_and_test(&map->users))257 return;258 259 if (map->pages && !use_ptemod) {260 /*261 * Increment the reference count. This ensures that the262 * subsequent call to unmap_grant_pages() will not wind up263 * re-entering itself. It *can* wind up calling264 * gntdev_put_map() recursively, but such calls will be with a265 * reference count greater than 1, so they will return before266 * this code is reached. The recursion depth is thus limited to267 * 1. Do NOT use refcount_inc() here, as it will detect that268 * the reference count is zero and WARN().269 */270 refcount_set(&map->users, 1);271 272 /*273 * Unmap the grants. This may or may not be asynchronous, so it274 * is possible that the reference count is 1 on return, but it275 * could also be greater than 1.276 */277 unmap_grant_pages(map, 0, map->count);278 279 /* Check if the memory now needs to be freed */280 if (!refcount_dec_and_test(&map->users))281 return;282 283 /*284 * All pages have been returned to the hypervisor, so free the285 * map.286 */287 }288 289 if (use_ptemod && map->notifier_init)290 mmu_interval_notifier_remove(&map->notifier);291 292 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {293 notify_remote_via_evtchn(map->notify.event);294 evtchn_put(map->notify.event);295 }296 gntdev_free_map(map);297}298 299/* ------------------------------------------------------------------ */300 301static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)302{303 struct gntdev_grant_map *map = data;304 unsigned int pgnr = (addr - map->pages_vm_start) >> PAGE_SHIFT;305 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte |306 (1 << _GNTMAP_guest_avail0);307 u64 pte_maddr;308 309 BUG_ON(pgnr >= map->count);310 pte_maddr = arbitrary_virt_to_machine(pte).maddr;311 312 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,313 map->grants[pgnr].ref,314 map->grants[pgnr].domid);315 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,316 INVALID_GRANT_HANDLE);317 return 0;318}319 320int gntdev_map_grant_pages(struct gntdev_grant_map *map)321{322 size_t alloced = 0;323 int i, err = 0;324 325 if (!use_ptemod) {326 /* Note: it could already be mapped */327 if (map->map_ops[0].handle != INVALID_GRANT_HANDLE)328 return 0;329 for (i = 0; i < map->count; i++) {330 unsigned long addr = (unsigned long)331 pfn_to_kaddr(page_to_pfn(map->pages[i]));332 gnttab_set_map_op(&map->map_ops[i], addr, map->flags,333 map->grants[i].ref,334 map->grants[i].domid);335 gnttab_set_unmap_op(&map->unmap_ops[i], addr,336 map->flags, INVALID_GRANT_HANDLE);337 }338 } else {339 /*340 * Setup the map_ops corresponding to the pte entries pointing341 * to the kernel linear addresses of the struct pages.342 * These ptes are completely different from the user ptes dealt343 * with find_grant_ptes.344 * Note that GNTMAP_device_map isn't needed here: The345 * dev_bus_addr output field gets consumed only from ->map_ops,346 * and by not requesting it when mapping we also avoid needing347 * to mirror dev_bus_addr into ->unmap_ops (and holding an extra348 * reference to the page in the hypervisor).349 */350 unsigned int flags = (map->flags & ~GNTMAP_device_map) |351 GNTMAP_host_map;352 353 for (i = 0; i < map->count; i++) {354 unsigned long address = (unsigned long)355 pfn_to_kaddr(page_to_pfn(map->pages[i]));356 BUG_ON(PageHighMem(map->pages[i]));357 358 gnttab_set_map_op(&map->kmap_ops[i], address, flags,359 map->grants[i].ref,360 map->grants[i].domid);361 gnttab_set_unmap_op(&map->kunmap_ops[i], address,362 flags, INVALID_GRANT_HANDLE);363 }364 }365 366 pr_debug("map %d+%d\n", map->index, map->count);367 err = gnttab_map_refs(map->map_ops, map->kmap_ops, map->pages,368 map->count);369 370 for (i = 0; i < map->count; i++) {371 if (map->map_ops[i].status == GNTST_okay) {372 map->unmap_ops[i].handle = map->map_ops[i].handle;373 alloced++;374 } else if (!err)375 err = -EINVAL;376 377 if (map->flags & GNTMAP_device_map)378 map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr;379 380 if (use_ptemod) {381 if (map->kmap_ops[i].status == GNTST_okay) {382 alloced++;383 map->kunmap_ops[i].handle = map->kmap_ops[i].handle;384 } else if (!err)385 err = -EINVAL;386 }387 }388 atomic_add(alloced, &map->live_grants);389 return err;390}391 392static void __unmap_grant_pages_done(int result,393 struct gntab_unmap_queue_data *data)394{395 unsigned int i;396 struct gntdev_grant_map *map = data->data;397 unsigned int offset = data->unmap_ops - map->unmap_ops;398 int successful_unmaps = 0;399 int live_grants;400 401 for (i = 0; i < data->count; i++) {402 if (map->unmap_ops[offset + i].status == GNTST_okay &&403 map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE)404 successful_unmaps++;405 406 WARN_ON(map->unmap_ops[offset + i].status != GNTST_okay &&407 map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE);408 pr_debug("unmap handle=%d st=%d\n",409 map->unmap_ops[offset+i].handle,410 map->unmap_ops[offset+i].status);411 map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;412 if (use_ptemod) {413 if (map->kunmap_ops[offset + i].status == GNTST_okay &&414 map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE)415 successful_unmaps++;416 417 WARN_ON(map->kunmap_ops[offset + i].status != GNTST_okay &&418 map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE);419 pr_debug("kunmap handle=%u st=%d\n",420 map->kunmap_ops[offset+i].handle,421 map->kunmap_ops[offset+i].status);422 map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;423 }424 }425 426 /*427 * Decrease the live-grant counter. This must happen after the loop to428 * prevent premature reuse of the grants by gnttab_mmap().429 */430 live_grants = atomic_sub_return(successful_unmaps, &map->live_grants);431 if (WARN_ON(live_grants < 0))432 pr_err("%s: live_grants became negative (%d) after unmapping %d pages!\n",433 __func__, live_grants, successful_unmaps);434 435 /* Release reference taken by __unmap_grant_pages */436 gntdev_put_map(NULL, map);437}438 439static void __unmap_grant_pages(struct gntdev_grant_map *map, int offset,440 int pages)441{442 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {443 int pgno = (map->notify.addr >> PAGE_SHIFT);444 445 if (pgno >= offset && pgno < offset + pages) {446 /* No need for kmap, pages are in lowmem */447 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));448 449 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;450 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;451 }452 }453 454 map->unmap_data.unmap_ops = map->unmap_ops + offset;455 map->unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;456 map->unmap_data.pages = map->pages + offset;457 map->unmap_data.count = pages;458 map->unmap_data.done = __unmap_grant_pages_done;459 map->unmap_data.data = map;460 refcount_inc(&map->users); /* to keep map alive during async call below */461 462 gnttab_unmap_refs_async(&map->unmap_data);463}464 465static void unmap_grant_pages(struct gntdev_grant_map *map, int offset,466 int pages)467{468 int range;469 470 if (atomic_read(&map->live_grants) == 0)471 return; /* Nothing to do */472 473 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);474 475 /* It is possible the requested range will have a "hole" where we476 * already unmapped some of the grants. Only unmap valid ranges.477 */478 while (pages) {479 while (pages && map->being_removed[offset]) {480 offset++;481 pages--;482 }483 range = 0;484 while (range < pages) {485 if (map->being_removed[offset + range])486 break;487 map->being_removed[offset + range] = true;488 range++;489 }490 if (range)491 __unmap_grant_pages(map, offset, range);492 offset += range;493 pages -= range;494 }495}496 497/* ------------------------------------------------------------------ */498 499static void gntdev_vma_open(struct vm_area_struct *vma)500{501 struct gntdev_grant_map *map = vma->vm_private_data;502 503 pr_debug("gntdev_vma_open %p\n", vma);504 refcount_inc(&map->users);505}506 507static void gntdev_vma_close(struct vm_area_struct *vma)508{509 struct gntdev_grant_map *map = vma->vm_private_data;510 struct file *file = vma->vm_file;511 struct gntdev_priv *priv = file->private_data;512 513 pr_debug("gntdev_vma_close %p\n", vma);514 515 vma->vm_private_data = NULL;516 gntdev_put_map(priv, map);517}518 519static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,520 unsigned long addr)521{522 struct gntdev_grant_map *map = vma->vm_private_data;523 524 return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT];525}526 527static const struct vm_operations_struct gntdev_vmops = {528 .open = gntdev_vma_open,529 .close = gntdev_vma_close,530 .find_special_page = gntdev_vma_find_special_page,531};532 533/* ------------------------------------------------------------------ */534 535static bool gntdev_invalidate(struct mmu_interval_notifier *mn,536 const struct mmu_notifier_range *range,537 unsigned long cur_seq)538{539 struct gntdev_grant_map *map =540 container_of(mn, struct gntdev_grant_map, notifier);541 unsigned long mstart, mend;542 unsigned long map_start, map_end;543 544 if (!mmu_notifier_range_blockable(range))545 return false;546 547 map_start = map->pages_vm_start;548 map_end = map->pages_vm_start + (map->count << PAGE_SHIFT);549 550 /*551 * If the VMA is split or otherwise changed the notifier is not552 * updated, but we don't want to process VA's outside the modified553 * VMA. FIXME: It would be much more understandable to just prevent554 * modifying the VMA in the first place.555 */556 if (map_start >= range->end || map_end <= range->start)557 return true;558 559 mstart = max(range->start, map_start);560 mend = min(range->end, map_end);561 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",562 map->index, map->count, map_start, map_end,563 range->start, range->end, mstart, mend);564 unmap_grant_pages(map, (mstart - map_start) >> PAGE_SHIFT,565 (mend - mstart) >> PAGE_SHIFT);566 567 return true;568}569 570static const struct mmu_interval_notifier_ops gntdev_mmu_ops = {571 .invalidate = gntdev_invalidate,572};573 574/* ------------------------------------------------------------------ */575 576static int gntdev_open(struct inode *inode, struct file *flip)577{578 struct gntdev_priv *priv;579 580 priv = kzalloc(sizeof(*priv), GFP_KERNEL);581 if (!priv)582 return -ENOMEM;583 584 INIT_LIST_HEAD(&priv->maps);585 mutex_init(&priv->lock);586 587#ifdef CONFIG_XEN_GNTDEV_DMABUF588 priv->dmabuf_priv = gntdev_dmabuf_init(flip);589 if (IS_ERR(priv->dmabuf_priv)) {590 int ret = PTR_ERR(priv->dmabuf_priv);591 592 kfree(priv);593 return ret;594 }595#endif596 597 flip->private_data = priv;598#ifdef CONFIG_XEN_GRANT_DMA_ALLOC599 priv->dma_dev = gntdev_miscdev.this_device;600 dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64));601#endif602 pr_debug("priv %p\n", priv);603 604 return 0;605}606 607static int gntdev_release(struct inode *inode, struct file *flip)608{609 struct gntdev_priv *priv = flip->private_data;610 struct gntdev_grant_map *map;611 612 pr_debug("priv %p\n", priv);613 614 mutex_lock(&priv->lock);615 while (!list_empty(&priv->maps)) {616 map = list_entry(priv->maps.next,617 struct gntdev_grant_map, next);618 list_del(&map->next);619 gntdev_put_map(NULL /* already removed */, map);620 }621 mutex_unlock(&priv->lock);622 623#ifdef CONFIG_XEN_GNTDEV_DMABUF624 gntdev_dmabuf_fini(priv->dmabuf_priv);625#endif626 627 kfree(priv);628 return 0;629}630 631static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,632 struct ioctl_gntdev_map_grant_ref __user *u)633{634 struct ioctl_gntdev_map_grant_ref op;635 struct gntdev_grant_map *map;636 int err;637 638 if (copy_from_user(&op, u, sizeof(op)) != 0)639 return -EFAULT;640 pr_debug("priv %p, add %d\n", priv, op.count);641 if (unlikely(gntdev_test_page_count(op.count)))642 return -EINVAL;643 644 err = -ENOMEM;645 map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */);646 if (!map)647 return err;648 649 if (copy_from_user(map->grants, &u->refs,650 sizeof(map->grants[0]) * op.count) != 0) {651 gntdev_put_map(NULL, map);652 return -EFAULT;653 }654 655 mutex_lock(&priv->lock);656 gntdev_add_map(priv, map);657 op.index = map->index << PAGE_SHIFT;658 mutex_unlock(&priv->lock);659 660 if (copy_to_user(u, &op, sizeof(op)) != 0)661 return -EFAULT;662 663 return 0;664}665 666static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,667 struct ioctl_gntdev_unmap_grant_ref __user *u)668{669 struct ioctl_gntdev_unmap_grant_ref op;670 struct gntdev_grant_map *map;671 int err = -ENOENT;672 673 if (copy_from_user(&op, u, sizeof(op)) != 0)674 return -EFAULT;675 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);676 677 mutex_lock(&priv->lock);678 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);679 if (map) {680 list_del(&map->next);681 err = 0;682 }683 mutex_unlock(&priv->lock);684 if (map)685 gntdev_put_map(priv, map);686 return err;687}688 689static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,690 struct ioctl_gntdev_get_offset_for_vaddr __user *u)691{692 struct ioctl_gntdev_get_offset_for_vaddr op;693 struct vm_area_struct *vma;694 struct gntdev_grant_map *map;695 int rv = -EINVAL;696 697 if (copy_from_user(&op, u, sizeof(op)) != 0)698 return -EFAULT;699 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);700 701 mmap_read_lock(current->mm);702 vma = find_vma(current->mm, op.vaddr);703 if (!vma || vma->vm_ops != &gntdev_vmops)704 goto out_unlock;705 706 map = vma->vm_private_data;707 if (!map)708 goto out_unlock;709 710 op.offset = map->index << PAGE_SHIFT;711 op.count = map->count;712 rv = 0;713 714 out_unlock:715 mmap_read_unlock(current->mm);716 717 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0)718 return -EFAULT;719 return rv;720}721 722static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)723{724 struct ioctl_gntdev_unmap_notify op;725 struct gntdev_grant_map *map;726 int rc;727 int out_flags;728 evtchn_port_t out_event;729 730 if (copy_from_user(&op, u, sizeof(op)))731 return -EFAULT;732 733 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))734 return -EINVAL;735 736 /* We need to grab a reference to the event channel we are going to use737 * to send the notify before releasing the reference we may already have738 * (if someone has called this ioctl twice). This is required so that739 * it is possible to change the clear_byte part of the notification740 * without disturbing the event channel part, which may now be the last741 * reference to that event channel.742 */743 if (op.action & UNMAP_NOTIFY_SEND_EVENT) {744 if (evtchn_get(op.event_channel_port))745 return -EINVAL;746 }747 748 out_flags = op.action;749 out_event = op.event_channel_port;750 751 mutex_lock(&priv->lock);752 753 list_for_each_entry(map, &priv->maps, next) {754 uint64_t begin = map->index << PAGE_SHIFT;755 uint64_t end = (map->index + map->count) << PAGE_SHIFT;756 if (op.index >= begin && op.index < end)757 goto found;758 }759 rc = -ENOENT;760 goto unlock_out;761 762 found:763 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&764 (map->flags & GNTMAP_readonly)) {765 rc = -EINVAL;766 goto unlock_out;767 }768 769 out_flags = map->notify.flags;770 out_event = map->notify.event;771 772 map->notify.flags = op.action;773 map->notify.addr = op.index - (map->index << PAGE_SHIFT);774 map->notify.event = op.event_channel_port;775 776 rc = 0;777 778 unlock_out:779 mutex_unlock(&priv->lock);780 781 /* Drop the reference to the event channel we did not save in the map */782 if (out_flags & UNMAP_NOTIFY_SEND_EVENT)783 evtchn_put(out_event);784 785 return rc;786}787 788#define GNTDEV_COPY_BATCH 16789 790struct gntdev_copy_batch {791 struct gnttab_copy ops[GNTDEV_COPY_BATCH];792 struct page *pages[GNTDEV_COPY_BATCH];793 s16 __user *status[GNTDEV_COPY_BATCH];794 unsigned int nr_ops;795 unsigned int nr_pages;796 bool writeable;797};798 799static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt,800 unsigned long *gfn)801{802 unsigned long addr = (unsigned long)virt;803 struct page *page;804 unsigned long xen_pfn;805 int ret;806 807 ret = pin_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page);808 if (ret < 0)809 return ret;810 811 batch->pages[batch->nr_pages++] = page;812 813 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK);814 *gfn = pfn_to_gfn(xen_pfn);815 816 return 0;817}818 819static void gntdev_put_pages(struct gntdev_copy_batch *batch)820{821 unpin_user_pages_dirty_lock(batch->pages, batch->nr_pages, batch->writeable);822 batch->nr_pages = 0;823 batch->writeable = false;824}825 826static int gntdev_copy(struct gntdev_copy_batch *batch)827{828 unsigned int i;829 830 gnttab_batch_copy(batch->ops, batch->nr_ops);831 gntdev_put_pages(batch);832 833 /*834 * For each completed op, update the status if the op failed835 * and all previous ops for the segment were successful.836 */837 for (i = 0; i < batch->nr_ops; i++) {838 s16 status = batch->ops[i].status;839 s16 old_status;840 841 if (status == GNTST_okay)842 continue;843 844 if (__get_user(old_status, batch->status[i]))845 return -EFAULT;846 847 if (old_status != GNTST_okay)848 continue;849 850 if (__put_user(status, batch->status[i]))851 return -EFAULT;852 }853 854 batch->nr_ops = 0;855 return 0;856}857 858static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch,859 struct gntdev_grant_copy_segment *seg,860 s16 __user *status)861{862 uint16_t copied = 0;863 864 /*865 * Disallow local -> local copies since there is only space in866 * batch->pages for one page per-op and this would be a very867 * expensive memcpy().868 */869 if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref)))870 return -EINVAL;871 872 /* Can't cross page if source/dest is a grant ref. */873 if (seg->flags & GNTCOPY_source_gref) {874 if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE)875 return -EINVAL;876 }877 if (seg->flags & GNTCOPY_dest_gref) {878 if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE)879 return -EINVAL;880 }881 882 if (put_user(GNTST_okay, status))883 return -EFAULT;884 885 while (copied < seg->len) {886 struct gnttab_copy *op;887 void __user *virt;888 size_t len, off;889 unsigned long gfn;890 int ret;891 892 if (batch->nr_ops >= GNTDEV_COPY_BATCH) {893 ret = gntdev_copy(batch);894 if (ret < 0)895 return ret;896 }897 898 len = seg->len - copied;899 900 op = &batch->ops[batch->nr_ops];901 op->flags = 0;902 903 if (seg->flags & GNTCOPY_source_gref) {904 op->source.u.ref = seg->source.foreign.ref;905 op->source.domid = seg->source.foreign.domid;906 op->source.offset = seg->source.foreign.offset + copied;907 op->flags |= GNTCOPY_source_gref;908 } else {909 virt = seg->source.virt + copied;910 off = (unsigned long)virt & ~XEN_PAGE_MASK;911 len = min(len, (size_t)XEN_PAGE_SIZE - off);912 batch->writeable = false;913 914 ret = gntdev_get_page(batch, virt, &gfn);915 if (ret < 0)916 return ret;917 918 op->source.u.gmfn = gfn;919 op->source.domid = DOMID_SELF;920 op->source.offset = off;921 }922 923 if (seg->flags & GNTCOPY_dest_gref) {924 op->dest.u.ref = seg->dest.foreign.ref;925 op->dest.domid = seg->dest.foreign.domid;926 op->dest.offset = seg->dest.foreign.offset + copied;927 op->flags |= GNTCOPY_dest_gref;928 } else {929 virt = seg->dest.virt + copied;930 off = (unsigned long)virt & ~XEN_PAGE_MASK;931 len = min(len, (size_t)XEN_PAGE_SIZE - off);932 batch->writeable = true;933 934 ret = gntdev_get_page(batch, virt, &gfn);935 if (ret < 0)936 return ret;937 938 op->dest.u.gmfn = gfn;939 op->dest.domid = DOMID_SELF;940 op->dest.offset = off;941 }942 943 op->len = len;944 copied += len;945 946 batch->status[batch->nr_ops] = status;947 batch->nr_ops++;948 }949 950 return 0;951}952 953static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u)954{955 struct ioctl_gntdev_grant_copy copy;956 struct gntdev_copy_batch batch;957 unsigned int i;958 int ret = 0;959 960 if (copy_from_user(©, u, sizeof(copy)))961 return -EFAULT;962 963 batch.nr_ops = 0;964 batch.nr_pages = 0;965 966 for (i = 0; i < copy.count; i++) {967 struct gntdev_grant_copy_segment seg;968 969 if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) {970 ret = -EFAULT;971 goto out;972 }973 974 ret = gntdev_grant_copy_seg(&batch, &seg, ©.segments[i].status);975 if (ret < 0)976 goto out;977 978 cond_resched();979 }980 if (batch.nr_ops)981 ret = gntdev_copy(&batch);982 return ret;983 984 out:985 gntdev_put_pages(&batch);986 return ret;987}988 989static long gntdev_ioctl(struct file *flip,990 unsigned int cmd, unsigned long arg)991{992 struct gntdev_priv *priv = flip->private_data;993 void __user *ptr = (void __user *)arg;994 995 switch (cmd) {996 case IOCTL_GNTDEV_MAP_GRANT_REF:997 return gntdev_ioctl_map_grant_ref(priv, ptr);998 999 case IOCTL_GNTDEV_UNMAP_GRANT_REF:1000 return gntdev_ioctl_unmap_grant_ref(priv, ptr);1001 1002 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:1003 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);1004 1005 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:1006 return gntdev_ioctl_notify(priv, ptr);1007 1008 case IOCTL_GNTDEV_GRANT_COPY:1009 return gntdev_ioctl_grant_copy(priv, ptr);1010 1011#ifdef CONFIG_XEN_GNTDEV_DMABUF1012 case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS:1013 return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr);1014 1015 case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED:1016 return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr);1017 1018 case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS:1019 return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr);1020 1021 case IOCTL_GNTDEV_DMABUF_IMP_RELEASE:1022 return gntdev_ioctl_dmabuf_imp_release(priv, ptr);1023#endif1024 1025 default:1026 pr_debug("priv %p, unknown cmd %x\n", priv, cmd);1027 return -ENOIOCTLCMD;1028 }1029 1030 return 0;1031}1032 1033static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)1034{1035 struct gntdev_priv *priv = flip->private_data;1036 int index = vma->vm_pgoff;1037 int count = vma_pages(vma);1038 struct gntdev_grant_map *map;1039 int err = -EINVAL;1040 1041 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))1042 return -EINVAL;1043 1044 pr_debug("map %d+%d at %lx (pgoff %lx)\n",1045 index, count, vma->vm_start, vma->vm_pgoff);1046 1047 mutex_lock(&priv->lock);1048 map = gntdev_find_map_index(priv, index, count);1049 if (!map)1050 goto unlock_out;1051 if (!atomic_add_unless(&map->in_use, 1, 1))1052 goto unlock_out;1053 1054 refcount_inc(&map->users);1055 1056 vma->vm_ops = &gntdev_vmops;1057 1058 vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP);1059 1060 if (use_ptemod)1061 vm_flags_set(vma, VM_DONTCOPY);1062 1063 vma->vm_private_data = map;1064 if (map->flags) {1065 if ((vma->vm_flags & VM_WRITE) &&1066 (map->flags & GNTMAP_readonly))1067 goto out_unlock_put;1068 } else {1069 map->flags = GNTMAP_host_map;1070 if (!(vma->vm_flags & VM_WRITE))1071 map->flags |= GNTMAP_readonly;1072 }1073 1074 map->pages_vm_start = vma->vm_start;1075 1076 if (use_ptemod) {1077 err = mmu_interval_notifier_insert_locked(1078 &map->notifier, vma->vm_mm, vma->vm_start,1079 vma->vm_end - vma->vm_start, &gntdev_mmu_ops);1080 if (err)1081 goto out_unlock_put;1082 1083 map->notifier_init = true;1084 }1085 mutex_unlock(&priv->lock);1086 1087 if (use_ptemod) {1088 /*1089 * gntdev takes the address of the PTE in find_grant_ptes() and1090 * passes it to the hypervisor in gntdev_map_grant_pages(). The1091 * purpose of the notifier is to prevent the hypervisor pointer1092 * to the PTE from going stale.1093 *1094 * Since this vma's mappings can't be touched without the1095 * mmap_lock, and we are holding it now, there is no need for1096 * the notifier_range locking pattern.1097 */1098 mmu_interval_read_begin(&map->notifier);1099 1100 err = apply_to_page_range(vma->vm_mm, vma->vm_start,1101 vma->vm_end - vma->vm_start,1102 find_grant_ptes, map);1103 if (err) {1104 pr_warn("find_grant_ptes() failure.\n");1105 goto out_put_map;1106 }1107 }1108 1109 err = gntdev_map_grant_pages(map);1110 if (err)1111 goto out_put_map;1112 1113 if (!use_ptemod) {1114 err = vm_map_pages_zero(vma, map->pages, map->count);1115 if (err)1116 goto out_put_map;1117 }1118 1119 return 0;1120 1121unlock_out:1122 mutex_unlock(&priv->lock);1123 return err;1124 1125out_unlock_put:1126 mutex_unlock(&priv->lock);1127out_put_map:1128 if (use_ptemod)1129 unmap_grant_pages(map, 0, map->count);1130 gntdev_put_map(priv, map);1131 return err;1132}1133 1134static const struct file_operations gntdev_fops = {1135 .owner = THIS_MODULE,1136 .open = gntdev_open,1137 .release = gntdev_release,1138 .mmap = gntdev_mmap,1139 .unlocked_ioctl = gntdev_ioctl1140};1141 1142static struct miscdevice gntdev_miscdev = {1143 .minor = MISC_DYNAMIC_MINOR,1144 .name = "xen/gntdev",1145 .fops = &gntdev_fops,1146};1147 1148/* ------------------------------------------------------------------ */1149 1150static int __init gntdev_init(void)1151{1152 int err;1153 1154 if (!xen_domain())1155 return -ENODEV;1156 1157 use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap);1158 1159 err = misc_register(&gntdev_miscdev);1160 if (err != 0) {1161 pr_err("Could not register gntdev device\n");1162 return err;1163 }1164 return 0;1165}1166 1167static void __exit gntdev_exit(void)1168{1169 misc_deregister(&gntdev_miscdev);1170}1171 1172module_init(gntdev_init);1173module_exit(gntdev_exit);1174 1175/* ------------------------------------------------------------------ */1176