/****************************************************************************** * 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 * (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc. * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "gntdev-common.h" #ifdef CONFIG_XEN_GNTDEV_DMABUF #include "gntdev-dmabuf.h" #endif MODULE_LICENSE("GPL"); MODULE_AUTHOR("Derek G. Murray , " "Gerd Hoffmann "); MODULE_DESCRIPTION("User-space granted page access driver"); static unsigned int limit = 64*1024; module_param(limit, uint, 0644); MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by one mapping request"); static int use_ptemod; static int unmap_grant_pages(struct gntdev_grant_map *map, int offset, int pages); static struct miscdevice gntdev_miscdev; /* ------------------------------------------------------------------ */ bool gntdev_test_page_count(unsigned int count) { return !count || count > limit; } static void gntdev_print_maps(struct gntdev_priv *priv, char *text, int text_index) { #ifdef DEBUG struct gntdev_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 gntdev_grant_map *map) { if (map == NULL) return; #ifdef CONFIG_XEN_GRANT_DMA_ALLOC if (map->dma_vaddr) { struct gnttab_dma_alloc_args args; args.dev = map->dma_dev; args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT); args.nr_pages = map->count; args.pages = map->pages; args.frames = map->frames; args.vaddr = map->dma_vaddr; args.dev_bus_addr = map->dma_bus_addr; gnttab_dma_free_pages(&args); } else #endif if (map->pages) gnttab_free_pages(map->count, map->pages); #ifdef CONFIG_XEN_GRANT_DMA_ALLOC kvfree(map->frames); #endif kvfree(map->pages); kvfree(map->grants); kvfree(map->map_ops); kvfree(map->unmap_ops); kvfree(map->kmap_ops); kvfree(map->kunmap_ops); kfree(map); } struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count, int dma_flags) { struct gntdev_grant_map *add; int i; add = kzalloc(sizeof(*add), GFP_KERNEL); if (NULL == add) return NULL; add->grants = kvcalloc(count, sizeof(add->grants[0]), GFP_KERNEL); add->map_ops = kvcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL); add->unmap_ops = kvcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL); add->pages = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL); if (NULL == add->grants || NULL == add->map_ops || NULL == add->unmap_ops || NULL == add->pages) goto err; if (use_ptemod) { add->kmap_ops = kvcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL); add->kunmap_ops = kvcalloc(count, sizeof(add->kunmap_ops[0]), GFP_KERNEL); if (NULL == add->kmap_ops || NULL == add->kunmap_ops) goto err; } #ifdef CONFIG_XEN_GRANT_DMA_ALLOC add->dma_flags = dma_flags; /* * Check if this mapping is requested to be backed * by a DMA buffer. */ if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) { struct gnttab_dma_alloc_args args; add->frames = kvcalloc(count, sizeof(add->frames[0]), GFP_KERNEL); if (!add->frames) goto err; /* Remember the device, so we can free DMA memory. */ add->dma_dev = priv->dma_dev; args.dev = priv->dma_dev; args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT); args.nr_pages = count; args.pages = add->pages; args.frames = add->frames; if (gnttab_dma_alloc_pages(&args)) goto err; add->dma_vaddr = args.vaddr; add->dma_bus_addr = args.dev_bus_addr; } else #endif 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 = -1; if (use_ptemod) { add->kmap_ops[i].handle = -1; add->kunmap_ops[i].handle = -1; } } add->index = 0; add->count = count; refcount_set(&add->users, 1); return add; err: gntdev_free_map(add); return NULL; } void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add) { struct gntdev_grant_map *map; list_for_each_entry(map, &priv->maps, next) { if (add->index + add->count < map->index) { list_add_tail(&add->next, &map->next); goto done; } add->index = map->index + map->count; } list_add_tail(&add->next, &priv->maps); done: gntdev_print_maps(priv, "[new]", add->index); } static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv, int index, int count) { struct gntdev_grant_map *map; list_for_each_entry(map, &priv->maps, next) { if (map->index != index) continue; if (count && map->count != count) continue; return map; } return NULL; } void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) { if (!map) return; if (!refcount_dec_and_test(&map->users)) return; if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { notify_remote_via_evtchn(map->notify.event); evtchn_put(map->notify.event); } if (map->pages && !use_ptemod) unmap_grant_pages(map, 0, map->count); gntdev_free_map(map); } /* ------------------------------------------------------------------ */ static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data) { struct gntdev_grant_map *map = data; unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte; u64 pte_maddr; BUG_ON(pgnr >= map->count); pte_maddr = arbitrary_virt_to_machine(pte).maddr; /* * Set the PTE as special to force get_user_pages_fast() fall * back to the slow path. If this is not supported as part of * the grant map, it will be done afterwards. */ if (xen_feature(XENFEAT_gnttab_map_avail_bits)) flags |= (1 << _GNTMAP_guest_avail0); gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags, map->grants[pgnr].ref, map->grants[pgnr].domid); gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags, -1 /* handle */); return 0; } #ifdef CONFIG_X86 static int set_grant_ptes_as_special(pte_t *pte, unsigned long addr, void *data) { set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte)); return 0; } #endif int gntdev_map_grant_pages(struct gntdev_grant_map *map) { int i, err = 0; if (!use_ptemod) { /* Note: it could already be mapped */ if (map->map_ops[0].handle != -1) return 0; for (i = 0; i < map->count; i++) { unsigned long addr = (unsigned long) pfn_to_kaddr(page_to_pfn(map->pages[i])); gnttab_set_map_op(&map->map_ops[i], addr, map->flags, map->grants[i].ref, map->grants[i].domid); gnttab_set_unmap_op(&map->unmap_ops[i], addr, map->flags, -1 /* handle */); } } else { /* * Setup the map_ops corresponding to the pte entries pointing * to the kernel linear addresses of the struct pages. * These ptes are completely different from the user ptes dealt * with find_grant_ptes. * Note that GNTMAP_device_map isn't needed here: The * dev_bus_addr output field gets consumed only from ->map_ops, * and by not requesting it when mapping we also avoid needing * to mirror dev_bus_addr into ->unmap_ops (and holding an extra * reference to the page in the hypervisor). */ unsigned int flags = (map->flags & ~GNTMAP_device_map) | GNTMAP_host_map; for (i = 0; i < map->count; i++) { unsigned long address = (unsigned long) pfn_to_kaddr(page_to_pfn(map->pages[i])); BUG_ON(PageHighMem(map->pages[i])); gnttab_set_map_op(&map->kmap_ops[i], address, flags, map->grants[i].ref, map->grants[i].domid); gnttab_set_unmap_op(&map->kunmap_ops[i], address, flags, -1); } } pr_debug("map %d+%d\n", map->index, map->count); err = gnttab_map_refs(map->map_ops, map->kmap_ops, map->pages, map->count); for (i = 0; i < map->count; i++) { if (map->map_ops[i].status == GNTST_okay) map->unmap_ops[i].handle = map->map_ops[i].handle; else if (!err) err = -EINVAL; if (map->flags & GNTMAP_device_map) map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr; if (use_ptemod) { if (map->kmap_ops[i].status == GNTST_okay) map->kunmap_ops[i].handle = map->kmap_ops[i].handle; else if (!err) err = -EINVAL; } } return err; } static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset, int pages) { int i, err = 0; struct gntab_unmap_queue_data unmap_data; if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { int pgno = (map->notify.addr >> PAGE_SHIFT); if (pgno >= offset && pgno < offset + pages) { /* No need for kmap, pages are in lowmem */ uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; } } unmap_data.unmap_ops = map->unmap_ops + offset; unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL; unmap_data.pages = map->pages + offset; unmap_data.count = pages; err = gnttab_unmap_refs_sync(&unmap_data); if (err) return err; for (i = 0; i < pages; i++) { if (map->unmap_ops[offset+i].status) err = -EINVAL; pr_debug("unmap handle=%d st=%d\n", map->unmap_ops[offset+i].handle, map->unmap_ops[offset+i].status); map->unmap_ops[offset+i].handle = -1; } return err; } static int unmap_grant_pages(struct gntdev_grant_map *map, int offset, int pages) { int range, err = 0; pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); /* It is possible the requested range will have a "hole" where we * already unmapped some of the grants. Only unmap valid ranges. */ while (pages && !err) { while (pages && map->unmap_ops[offset].handle == -1) { offset++; pages--; } range = 0; while (range < pages) { if (map->unmap_ops[offset+range].handle == -1) break; range++; } err = __unmap_grant_pages(map, offset, range); offset += range; pages -= range; } return err; } /* ------------------------------------------------------------------ */ static void gntdev_vma_open(struct vm_area_struct *vma) { struct gntdev_grant_map *map = vma->vm_private_data; pr_debug("gntdev_vma_open %p\n", vma); refcount_inc(&map->users); } static void gntdev_vma_close(struct vm_area_struct *vma) { struct gntdev_grant_map *map = vma->vm_private_data; struct file *file = vma->vm_file; struct gntdev_priv *priv = file->private_data; pr_debug("gntdev_vma_close %p\n", vma); if (use_ptemod) { WARN_ON(map->vma != vma); mmu_interval_notifier_remove(&map->notifier); map->vma = NULL; } vma->vm_private_data = NULL; gntdev_put_map(priv, map); } static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma, unsigned long addr) { struct gntdev_grant_map *map = vma->vm_private_data; return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT]; } static const struct vm_operations_struct gntdev_vmops = { .open = gntdev_vma_open, .close = gntdev_vma_close, .find_special_page = gntdev_vma_find_special_page, }; /* ------------------------------------------------------------------ */ static bool gntdev_invalidate(struct mmu_interval_notifier *mn, const struct mmu_notifier_range *range, unsigned long cur_seq) { struct gntdev_grant_map *map = container_of(mn, struct gntdev_grant_map, notifier); unsigned long mstart, mend; int err; if (!mmu_notifier_range_blockable(range)) return false; /* * If the VMA is split or otherwise changed the notifier is not * updated, but we don't want to process VA's outside the modified * VMA. FIXME: It would be much more understandable to just prevent * modifying the VMA in the first place. */ if (map->vma->vm_start >= range->end || map->vma->vm_end <= range->start) return true; mstart = max(range->start, map->vma->vm_start); mend = min(range->end, map->vma->vm_end); pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", map->index, map->count, map->vma->vm_start, map->vma->vm_end, range->start, range->end, mstart, mend); err = unmap_grant_pages(map, (mstart - map->vma->vm_start) >> PAGE_SHIFT, (mend - mstart) >> PAGE_SHIFT); WARN_ON(err); return true; } static const struct mmu_interval_notifier_ops gntdev_mmu_ops = { .invalidate = gntdev_invalidate, }; /* ------------------------------------------------------------------ */ static int gntdev_open(struct inode *inode, struct file *flip) { struct gntdev_priv *priv; priv = kzalloc(sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; INIT_LIST_HEAD(&priv->maps); mutex_init(&priv->lock); #ifdef CONFIG_XEN_GNTDEV_DMABUF priv->dmabuf_priv = gntdev_dmabuf_init(flip); if (IS_ERR(priv->dmabuf_priv)) { int ret = PTR_ERR(priv->dmabuf_priv); kfree(priv); return ret; } #endif flip->private_data = priv; #ifdef CONFIG_XEN_GRANT_DMA_ALLOC priv->dma_dev = gntdev_miscdev.this_device; dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64)); #endif pr_debug("priv %p\n", priv); return 0; } static int gntdev_release(struct inode *inode, struct file *flip) { struct gntdev_priv *priv = flip->private_data; struct gntdev_grant_map *map; pr_debug("priv %p\n", priv); mutex_lock(&priv->lock); while (!list_empty(&priv->maps)) { map = list_entry(priv->maps.next, struct gntdev_grant_map, next); list_del(&map->next); gntdev_put_map(NULL /* already removed */, map); } mutex_unlock(&priv->lock); #ifdef CONFIG_XEN_GNTDEV_DMABUF gntdev_dmabuf_fini(priv->dmabuf_priv); #endif kfree(priv); return 0; } static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, struct ioctl_gntdev_map_grant_ref __user *u) { struct ioctl_gntdev_map_grant_ref op; struct gntdev_grant_map *map; int err; if (copy_from_user(&op, u, sizeof(op)) != 0) return -EFAULT; pr_debug("priv %p, add %d\n", priv, op.count); if (unlikely(gntdev_test_page_count(op.count))) return -EINVAL; err = -ENOMEM; map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */); if (!map) return err; if (copy_from_user(map->grants, &u->refs, sizeof(map->grants[0]) * op.count) != 0) { gntdev_put_map(NULL, map); return -EFAULT; } mutex_lock(&priv->lock); gntdev_add_map(priv, map); op.index = map->index << PAGE_SHIFT; mutex_unlock(&priv->lock); if (copy_to_user(u, &op, sizeof(op)) != 0) return -EFAULT; return 0; } static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, struct ioctl_gntdev_unmap_grant_ref __user *u) { struct ioctl_gntdev_unmap_grant_ref op; struct gntdev_grant_map *map; int err = -ENOENT; if (copy_from_user(&op, u, sizeof(op)) != 0) return -EFAULT; pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); mutex_lock(&priv->lock); map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); if (map) { list_del(&map->next); err = 0; } mutex_unlock(&priv->lock); if (map) gntdev_put_map(priv, map); return err; } static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, struct ioctl_gntdev_get_offset_for_vaddr __user *u) { struct ioctl_gntdev_get_offset_for_vaddr op; struct vm_area_struct *vma; struct gntdev_grant_map *map; int rv = -EINVAL; if (copy_from_user(&op, u, sizeof(op)) != 0) return -EFAULT; pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr); mmap_read_lock(current->mm); vma = find_vma(current->mm, op.vaddr); if (!vma || vma->vm_ops != &gntdev_vmops) goto out_unlock; map = vma->vm_private_data; if (!map) goto out_unlock; op.offset = map->index << PAGE_SHIFT; op.count = map->count; rv = 0; out_unlock: mmap_read_unlock(current->mm); if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) return -EFAULT; return rv; } static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) { struct ioctl_gntdev_unmap_notify op; struct gntdev_grant_map *map; int rc; int out_flags; evtchn_port_t out_event; if (copy_from_user(&op, u, sizeof(op))) return -EFAULT; if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) return -EINVAL; /* We need to grab a reference to the event channel we are going to use * to send the notify before releasing the reference we may already have * (if someone has called this ioctl twice). This is required so that * it is possible to change the clear_byte part of the notification * without disturbing the event channel part, which may now be the last * reference to that event channel. */ if (op.action & UNMAP_NOTIFY_SEND_EVENT) { if (evtchn_get(op.event_channel_port)) return -EINVAL; } out_flags = op.action; out_event = op.event_channel_port; mutex_lock(&priv->lock); list_for_each_entry(map, &priv->maps, next) { uint64_t begin = map->index << PAGE_SHIFT; uint64_t end = (map->index + map->count) << PAGE_SHIFT; if (op.index >= begin && op.index < end) goto found; } rc = -ENOENT; goto unlock_out; found: if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && (map->flags & GNTMAP_readonly)) { rc = -EINVAL; goto unlock_out; } out_flags = map->notify.flags; out_event = map->notify.event; map->notify.flags = op.action; map->notify.addr = op.index - (map->index << PAGE_SHIFT); map->notify.event = op.event_channel_port; rc = 0; unlock_out: mutex_unlock(&priv->lock); /* Drop the reference to the event channel we did not save in the map */ if (out_flags & UNMAP_NOTIFY_SEND_EVENT) evtchn_put(out_event); return rc; } #define GNTDEV_COPY_BATCH 16 struct gntdev_copy_batch { struct gnttab_copy ops[GNTDEV_COPY_BATCH]; struct page *pages[GNTDEV_COPY_BATCH]; s16 __user *status[GNTDEV_COPY_BATCH]; unsigned int nr_ops; unsigned int nr_pages; bool writeable; }; static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, unsigned long *gfn) { unsigned long addr = (unsigned long)virt; struct page *page; unsigned long xen_pfn; int ret; ret = pin_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page); if (ret < 0) return ret; batch->pages[batch->nr_pages++] = page; xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK); *gfn = pfn_to_gfn(xen_pfn); return 0; } static void gntdev_put_pages(struct gntdev_copy_batch *batch) { unpin_user_pages_dirty_lock(batch->pages, batch->nr_pages, batch->writeable); batch->nr_pages = 0; batch->writeable = false; } static int gntdev_copy(struct gntdev_copy_batch *batch) { unsigned int i; gnttab_batch_copy(batch->ops, batch->nr_ops); gntdev_put_pages(batch); /* * For each completed op, update the status if the op failed * and all previous ops for the segment were successful. */ for (i = 0; i < batch->nr_ops; i++) { s16 status = batch->ops[i].status; s16 old_status; if (status == GNTST_okay) continue; if (__get_user(old_status, batch->status[i])) return -EFAULT; if (old_status != GNTST_okay) continue; if (__put_user(status, batch->status[i])) return -EFAULT; } batch->nr_ops = 0; return 0; } static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, struct gntdev_grant_copy_segment *seg, s16 __user *status) { uint16_t copied = 0; /* * Disallow local -> local copies since there is only space in * batch->pages for one page per-op and this would be a very * expensive memcpy(). */ if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref))) return -EINVAL; /* Can't cross page if source/dest is a grant ref. */ if (seg->flags & GNTCOPY_source_gref) { if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE) return -EINVAL; } if (seg->flags & GNTCOPY_dest_gref) { if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE) return -EINVAL; } if (put_user(GNTST_okay, status)) return -EFAULT; while (copied < seg->len) { struct gnttab_copy *op; void __user *virt; size_t len, off; unsigned long gfn; int ret; if (batch->nr_ops >= GNTDEV_COPY_BATCH) { ret = gntdev_copy(batch); if (ret < 0) return ret; } len = seg->len - copied; op = &batch->ops[batch->nr_ops]; op->flags = 0; if (seg->flags & GNTCOPY_source_gref) { op->source.u.ref = seg->source.foreign.ref; op->source.domid = seg->source.foreign.domid; op->source.offset = seg->source.foreign.offset + copied; op->flags |= GNTCOPY_source_gref; } else { virt = seg->source.virt + copied; off = (unsigned long)virt & ~XEN_PAGE_MASK; len = min(len, (size_t)XEN_PAGE_SIZE - off); batch->writeable = false; ret = gntdev_get_page(batch, virt, &gfn); if (ret < 0) return ret; op->source.u.gmfn = gfn; op->source.domid = DOMID_SELF; op->source.offset = off; } if (seg->flags & GNTCOPY_dest_gref) { op->dest.u.ref = seg->dest.foreign.ref; op->dest.domid = seg->dest.foreign.domid; op->dest.offset = seg->dest.foreign.offset + copied; op->flags |= GNTCOPY_dest_gref; } else { virt = seg->dest.virt + copied; off = (unsigned long)virt & ~XEN_PAGE_MASK; len = min(len, (size_t)XEN_PAGE_SIZE - off); batch->writeable = true; ret = gntdev_get_page(batch, virt, &gfn); if (ret < 0) return ret; op->dest.u.gmfn = gfn; op->dest.domid = DOMID_SELF; op->dest.offset = off; } op->len = len; copied += len; batch->status[batch->nr_ops] = status; batch->nr_ops++; } return 0; } static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u) { struct ioctl_gntdev_grant_copy copy; struct gntdev_copy_batch batch; unsigned int i; int ret = 0; if (copy_from_user(©, u, sizeof(copy))) return -EFAULT; batch.nr_ops = 0; batch.nr_pages = 0; for (i = 0; i < copy.count; i++) { struct gntdev_grant_copy_segment seg; if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) { ret = -EFAULT; goto out; } ret = gntdev_grant_copy_seg(&batch, &seg, ©.segments[i].status); if (ret < 0) goto out; cond_resched(); } if (batch.nr_ops) ret = gntdev_copy(&batch); return ret; out: gntdev_put_pages(&batch); return ret; } static long gntdev_ioctl(struct file *flip, unsigned int cmd, unsigned long arg) { struct gntdev_priv *priv = flip->private_data; void __user *ptr = (void __user *)arg; switch (cmd) { case IOCTL_GNTDEV_MAP_GRANT_REF: return gntdev_ioctl_map_grant_ref(priv, ptr); case IOCTL_GNTDEV_UNMAP_GRANT_REF: return gntdev_ioctl_unmap_grant_ref(priv, ptr); case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: return gntdev_ioctl_notify(priv, ptr); case IOCTL_GNTDEV_GRANT_COPY: return gntdev_ioctl_grant_copy(priv, ptr); #ifdef CONFIG_XEN_GNTDEV_DMABUF case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS: return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr); case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED: return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr); case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS: return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr); case IOCTL_GNTDEV_DMABUF_IMP_RELEASE: return gntdev_ioctl_dmabuf_imp_release(priv, ptr); #endif default: pr_debug("priv %p, unknown cmd %x\n", priv, cmd); return -ENOIOCTLCMD; } return 0; } static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) { struct gntdev_priv *priv = flip->private_data; int index = vma->vm_pgoff; int count = vma_pages(vma); struct gntdev_grant_map *map; int err = -EINVAL; if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) return -EINVAL; pr_debug("map %d+%d at %lx (pgoff %lx)\n", index, count, vma->vm_start, vma->vm_pgoff); mutex_lock(&priv->lock); map = gntdev_find_map_index(priv, index, count); if (!map) goto unlock_out; if (use_ptemod && map->vma) goto unlock_out; refcount_inc(&map->users); vma->vm_ops = &gntdev_vmops; vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP; if (use_ptemod) vma->vm_flags |= VM_DONTCOPY; vma->vm_private_data = map; if (map->flags) { if ((vma->vm_flags & VM_WRITE) && (map->flags & GNTMAP_readonly)) goto out_unlock_put; } else { map->flags = GNTMAP_host_map; if (!(vma->vm_flags & VM_WRITE)) map->flags |= GNTMAP_readonly; } if (use_ptemod) { map->vma = vma; err = mmu_interval_notifier_insert_locked( &map->notifier, vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, &gntdev_mmu_ops); if (err) goto out_unlock_put; } mutex_unlock(&priv->lock); if (use_ptemod) { /* * gntdev takes the address of the PTE in find_grant_ptes() and * passes it to the hypervisor in gntdev_map_grant_pages(). The * purpose of the notifier is to prevent the hypervisor pointer * to the PTE from going stale. * * Since this vma's mappings can't be touched without the * mmap_lock, and we are holding it now, there is no need for * the notifier_range locking pattern. */ mmu_interval_read_begin(&map->notifier); map->pages_vm_start = vma->vm_start; err = apply_to_page_range(vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, find_grant_ptes, map); if (err) { pr_warn("find_grant_ptes() failure.\n"); goto out_put_map; } } err = gntdev_map_grant_pages(map); if (err) goto out_put_map; if (!use_ptemod) { err = vm_map_pages_zero(vma, map->pages, map->count); if (err) goto out_put_map; } else { #ifdef CONFIG_X86 /* * If the PTEs were not made special by the grant map * hypercall, do so here. * * This is racy since the mapping is already visible * to userspace but userspace should be well-behaved * enough to not touch it until the mmap() call * returns. */ if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) { apply_to_page_range(vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, set_grant_ptes_as_special, NULL); } #endif } return 0; unlock_out: mutex_unlock(&priv->lock); return err; out_unlock_put: mutex_unlock(&priv->lock); out_put_map: if (use_ptemod) { unmap_grant_pages(map, 0, map->count); if (map->vma) { mmu_interval_notifier_remove(&map->notifier); map->vma = NULL; } } gntdev_put_map(priv, map); return err; } static const struct file_operations gntdev_fops = { .owner = THIS_MODULE, .open = gntdev_open, .release = gntdev_release, .mmap = gntdev_mmap, .unlocked_ioctl = gntdev_ioctl }; static struct miscdevice gntdev_miscdev = { .minor = MISC_DYNAMIC_MINOR, .name = "xen/gntdev", .fops = &gntdev_fops, }; /* ------------------------------------------------------------------ */ static int __init gntdev_init(void) { int err; if (!xen_domain()) return -ENODEV; use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap); err = misc_register(&gntdev_miscdev); if (err != 0) { pr_err("Could not register gntdev device\n"); return err; } return 0; } static void __exit gntdev_exit(void) { misc_deregister(&gntdev_miscdev); } module_init(gntdev_init); module_exit(gntdev_exit); /* ------------------------------------------------------------------ */