| /****************************************************************************** |
| * gntdev.c |
| * |
| * Device for accessing (in user-space) pages that have been granted by other |
| * domains. |
| * |
| * Copyright (c) 2006-2007, D G Murray. |
| * (c) 2009 Gerd Hoffmann <kraxel@redhat.com> |
| * (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 <linux/module.h> |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/miscdevice.h> |
| #include <linux/fs.h> |
| #include <linux/uaccess.h> |
| #include <linux/sched.h> |
| #include <linux/sched/mm.h> |
| #include <linux/spinlock.h> |
| #include <linux/slab.h> |
| #include <linux/highmem.h> |
| #include <linux/refcount.h> |
| #ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
| #include <linux/of_device.h> |
| #endif |
| |
| #include <xen/xen.h> |
| #include <xen/grant_table.h> |
| #include <xen/balloon.h> |
| #include <xen/gntdev.h> |
| #include <xen/events.h> |
| #include <xen/page.h> |
| #include <asm/xen/hypervisor.h> |
| #include <asm/xen/hypercall.h> |
| |
| #include "gntdev-common.h" |
| #ifdef CONFIG_XEN_GNTDEV_DMABUF |
| #include "gntdev-dmabuf.h" |
| #endif |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, " |
| "Gerd Hoffmann <kraxel@redhat.com>"); |
| MODULE_DESCRIPTION("User-space granted page access driver"); |
| |
| static int limit = 1024*1024; |
| module_param(limit, int, 0644); |
| MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by " |
| "the gntdev device"); |
| |
| static atomic_t pages_mapped = ATOMIC_INIT(0); |
| |
| static int use_ptemod; |
| #define populate_freeable_maps use_ptemod |
| |
| static int unmap_grant_pages(struct gntdev_grant_map *map, |
| int offset, int pages); |
| |
| static struct miscdevice gntdev_miscdev; |
| |
| /* ------------------------------------------------------------------ */ |
| |
| bool gntdev_account_mapped_pages(int count) |
| { |
| return atomic_add_return(count, &pages_mapped) > 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 |
| kfree(map->frames); |
| #endif |
| kfree(map->pages); |
| kfree(map->grants); |
| kfree(map->map_ops); |
| kfree(map->unmap_ops); |
| kfree(map->kmap_ops); |
| kfree(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 = kcalloc(count, sizeof(add->grants[0]), GFP_KERNEL); |
| add->map_ops = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL); |
| add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL); |
| add->kmap_ops = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL); |
| add->kunmap_ops = kcalloc(count, sizeof(add->kunmap_ops[0]), GFP_KERNEL); |
| add->pages = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL); |
| if (NULL == add->grants || |
| NULL == add->map_ops || |
| NULL == add->unmap_ops || |
| NULL == add->kmap_ops || |
| NULL == add->kunmap_ops || |
| NULL == add->pages) |
| goto err; |
| |
| #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 = kcalloc(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; |
| 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; |
| |
| atomic_sub(map->count, &pages_mapped); |
| |
| if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { |
| notify_remote_via_evtchn(map->notify.event); |
| evtchn_put(map->notify.event); |
| } |
| |
| if (populate_freeable_maps && priv) { |
| mutex_lock(&priv->lock); |
| list_del(&map->next); |
| mutex_unlock(&priv->lock); |
| } |
| |
| if (map->pages && !use_ptemod) |
| unmap_grant_pages(map, 0, map->count); |
| gntdev_free_map(map); |
| } |
| |
| /* ------------------------------------------------------------------ */ |
| |
| static int find_grant_ptes(pte_t *pte, pgtable_t token, |
| 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, pgtable_t token, |
| 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. |
| */ |
| 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, |
| map->flags | GNTMAP_host_map, |
| map->grants[i].ref, |
| map->grants[i].domid); |
| gnttab_set_unmap_op(&map->kunmap_ops[i], address, |
| map->flags | GNTMAP_host_map, -1); |
| } |
| } |
| |
| pr_debug("map %d+%d\n", map->index, map->count); |
| err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL, |
| map->pages, map->count); |
| if (err) |
| return err; |
| |
| for (i = 0; i < map->count; i++) { |
| if (map->map_ops[i].status) { |
| err = -EINVAL; |
| continue; |
| } |
| |
| map->unmap_ops[i].handle = map->map_ops[i].handle; |
| if (use_ptemod) |
| map->kunmap_ops[i].handle = map->kmap_ops[i].handle; |
| #ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
| else if (map->dma_vaddr) { |
| unsigned long bfn; |
| |
| bfn = pfn_to_bfn(page_to_pfn(map->pages[i])); |
| map->unmap_ops[i].dev_bus_addr = __pfn_to_phys(bfn); |
| } |
| #endif |
| } |
| 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) { |
| /* It is possible that an mmu notifier could be running |
| * concurrently, so take priv->lock to ensure that the vma won't |
| * vanishing during the unmap_grant_pages call, since we will |
| * spin here until that completes. Such a concurrent call will |
| * not do any unmapping, since that has been done prior to |
| * closing the vma, but it may still iterate the unmap_ops list. |
| */ |
| mutex_lock(&priv->lock); |
| map->vma = NULL; |
| mutex_unlock(&priv->lock); |
| } |
| 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 in_range(struct gntdev_grant_map *map, |
| unsigned long start, unsigned long end) |
| { |
| if (!map->vma) |
| return false; |
| if (map->vma->vm_start >= end) |
| return false; |
| if (map->vma->vm_end <= start) |
| return false; |
| |
| return true; |
| } |
| |
| static int unmap_if_in_range(struct gntdev_grant_map *map, |
| unsigned long start, unsigned long end, |
| bool blockable) |
| { |
| unsigned long mstart, mend; |
| int err; |
| |
| if (!in_range(map, start, end)) |
| return 0; |
| |
| if (!blockable) |
| return -EAGAIN; |
| |
| mstart = max(start, map->vma->vm_start); |
| mend = min(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, |
| start, end, mstart, mend); |
| err = unmap_grant_pages(map, |
| (mstart - map->vma->vm_start) >> PAGE_SHIFT, |
| (mend - mstart) >> PAGE_SHIFT); |
| WARN_ON(err); |
| |
| return 0; |
| } |
| |
| static int mn_invl_range_start(struct mmu_notifier *mn, |
| const struct mmu_notifier_range *range) |
| { |
| struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); |
| struct gntdev_grant_map *map; |
| int ret = 0; |
| |
| if (range->blockable) |
| mutex_lock(&priv->lock); |
| else if (!mutex_trylock(&priv->lock)) |
| return -EAGAIN; |
| |
| list_for_each_entry(map, &priv->maps, next) { |
| ret = unmap_if_in_range(map, range->start, range->end, |
| range->blockable); |
| if (ret) |
| goto out_unlock; |
| } |
| list_for_each_entry(map, &priv->freeable_maps, next) { |
| ret = unmap_if_in_range(map, range->start, range->end, |
| range->blockable); |
| if (ret) |
| goto out_unlock; |
| } |
| |
| out_unlock: |
| mutex_unlock(&priv->lock); |
| |
| return ret; |
| } |
| |
| static void mn_release(struct mmu_notifier *mn, |
| struct mm_struct *mm) |
| { |
| struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); |
| struct gntdev_grant_map *map; |
| int err; |
| |
| mutex_lock(&priv->lock); |
| list_for_each_entry(map, &priv->maps, next) { |
| if (!map->vma) |
| continue; |
| pr_debug("map %d+%d (%lx %lx)\n", |
| map->index, map->count, |
| map->vma->vm_start, map->vma->vm_end); |
| err = unmap_grant_pages(map, /* offset */ 0, map->count); |
| WARN_ON(err); |
| } |
| list_for_each_entry(map, &priv->freeable_maps, next) { |
| if (!map->vma) |
| continue; |
| pr_debug("map %d+%d (%lx %lx)\n", |
| map->index, map->count, |
| map->vma->vm_start, map->vma->vm_end); |
| err = unmap_grant_pages(map, /* offset */ 0, map->count); |
| WARN_ON(err); |
| } |
| mutex_unlock(&priv->lock); |
| } |
| |
| static const struct mmu_notifier_ops gntdev_mmu_ops = { |
| .release = mn_release, |
| .invalidate_range_start = mn_invl_range_start, |
| }; |
| |
| /* ------------------------------------------------------------------ */ |
| |
| static int gntdev_open(struct inode *inode, struct file *flip) |
| { |
| struct gntdev_priv *priv; |
| int ret = 0; |
| |
| priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
| if (!priv) |
| return -ENOMEM; |
| |
| INIT_LIST_HEAD(&priv->maps); |
| INIT_LIST_HEAD(&priv->freeable_maps); |
| mutex_init(&priv->lock); |
| |
| #ifdef CONFIG_XEN_GNTDEV_DMABUF |
| priv->dmabuf_priv = gntdev_dmabuf_init(flip); |
| if (IS_ERR(priv->dmabuf_priv)) { |
| ret = PTR_ERR(priv->dmabuf_priv); |
| kfree(priv); |
| return ret; |
| } |
| #endif |
| |
| if (use_ptemod) { |
| priv->mm = get_task_mm(current); |
| if (!priv->mm) { |
| kfree(priv); |
| return -ENOMEM; |
| } |
| priv->mn.ops = &gntdev_mmu_ops; |
| ret = mmu_notifier_register(&priv->mn, priv->mm); |
| mmput(priv->mm); |
| } |
| |
| if (ret) { |
| kfree(priv); |
| return ret; |
| } |
| |
| flip->private_data = priv; |
| #ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
| priv->dma_dev = gntdev_miscdev.this_device; |
| |
| /* |
| * The device is not spawn from a device tree, so arch_setup_dma_ops |
| * is not called, thus leaving the device with dummy DMA ops. |
| * Fix this by calling of_dma_configure() with a NULL node to set |
| * default DMA ops. |
| */ |
| of_dma_configure(priv->dma_dev, NULL, true); |
| #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); |
| } |
| WARN_ON(!list_empty(&priv->freeable_maps)); |
| mutex_unlock(&priv->lock); |
| |
| #ifdef CONFIG_XEN_GNTDEV_DMABUF |
| gntdev_dmabuf_fini(priv->dmabuf_priv); |
| #endif |
| |
| if (use_ptemod) |
| mmu_notifier_unregister(&priv->mn, priv->mm); |
| |
| 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(op.count <= 0)) |
| return -EINVAL; |
| |
| err = -ENOMEM; |
| map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */); |
| if (!map) |
| return err; |
| |
| if (unlikely(gntdev_account_mapped_pages(op.count))) { |
| pr_debug("can't map: over limit\n"); |
| gntdev_put_map(NULL, 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); |
| if (populate_freeable_maps) |
| list_add_tail(&map->next, &priv->freeable_maps); |
| 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); |
| |
| down_read(¤t->mm->mmap_sem); |
| 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: |
| up_read(¤t->mm->mmap_sem); |
| |
| 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; |
| unsigned int 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; |
| }; |
| |
| static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, |
| bool writeable, unsigned long *gfn) |
| { |
| unsigned long addr = (unsigned long)virt; |
| struct page *page; |
| unsigned long xen_pfn; |
| int ret; |
| |
| ret = get_user_pages_fast(addr, 1, writeable, &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) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < batch->nr_pages; i++) |
| put_page(batch->pages[i]); |
| batch->nr_pages = 0; |
| } |
| |
| 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); |
| |
| ret = gntdev_get_page(batch, virt, false, &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); |
| |
| ret = gntdev_get_page(batch, virt, true, &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 i, 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; |
| if (use_ptemod && priv->mm != vma->vm_mm) { |
| pr_warn("Huh? Other mm?\n"); |
| 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 (use_ptemod) |
| map->vma = vma; |
| |
| 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; |
| } |
| |
| mutex_unlock(&priv->lock); |
| |
| if (use_ptemod) { |
| 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) { |
| for (i = 0; i < count; i++) { |
| err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE, |
| map->pages[i]); |
| 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) { |
| map->vma = NULL; |
| unmap_grant_pages(map, 0, map->count); |
| } |
| 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); |
| |
| /* ------------------------------------------------------------------ */ |