v4.19.13 snapshot.
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
new file mode 100644
index 0000000..b0b02a5
--- /dev/null
+++ b/drivers/xen/gntdev.c
@@ -0,0 +1,1231 @@
+/******************************************************************************
+ * 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,
+ struct mm_struct *mm,
+ unsigned long start, unsigned long end,
+ bool blockable)
+{
+ struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
+ struct gntdev_grant_map *map;
+ int ret = 0;
+
+ if (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, start, end, blockable);
+ if (ret)
+ goto out_unlock;
+ }
+ list_for_each_entry(map, &priv->freeable_maps, next) {
+ ret = unmap_if_in_range(map, start, end, 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();
+ 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);
+
+/* ------------------------------------------------------------------ */