blob: 4547a91bca67a1005c95c478aef929d121655d00 [file] [log] [blame]
Daniel De Graafdd314052011-02-07 17:23:05 -05001/******************************************************************************
2 * gntalloc.c
3 *
4 * Device for creating grant references (in user-space) that may be shared
5 * with other domains.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
11 *
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
15 */
16
17/*
18 * This driver exists to allow userspace programs in Linux to allocate kernel
19 * memory that will later be shared with another domain. Without this device,
20 * Linux userspace programs cannot create grant references.
21 *
22 * How this stuff works:
23 * X -> granting a page to Y
24 * Y -> mapping the grant from X
25 *
26 * 1. X uses the gntalloc device to allocate a page of kernel memory, P.
27 * 2. X creates an entry in the grant table that says domid(Y) can access P.
28 * This is done without a hypercall unless the grant table needs expansion.
29 * 3. X gives the grant reference identifier, GREF, to Y.
30 * 4. Y maps the page, either directly into kernel memory for use in a backend
31 * driver, or via a the gntdev device to map into the address space of an
32 * application running in Y. This is the first point at which Xen does any
33 * tracking of the page.
34 * 5. A program in X mmap()s a segment of the gntalloc device that corresponds
35 * to the shared page, and can now communicate with Y over the shared page.
36 *
37 *
38 * NOTE TO USERSPACE LIBRARIES:
39 * The grant allocation and mmap()ing are, naturally, two separate operations.
40 * You set up the sharing by calling the create ioctl() and then the mmap().
41 * Teardown requires munmap() and either close() or ioctl().
42 *
43 * WARNING: Since Xen does not allow a guest to forcibly end the use of a grant
44 * reference, this device can be used to consume kernel memory by leaving grant
45 * references mapped by another domain when an application exits. Therefore,
46 * there is a global limit on the number of pages that can be allocated. When
47 * all references to the page are unmapped, it will be freed during the next
48 * grant operation.
49 */
50
Joe Perches283c0972013-06-28 03:21:41 -070051#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
52
Daniel De Graafdd314052011-02-07 17:23:05 -050053#include <linux/atomic.h>
54#include <linux/module.h>
55#include <linux/miscdevice.h>
56#include <linux/kernel.h>
57#include <linux/init.h>
58#include <linux/slab.h>
59#include <linux/fs.h>
60#include <linux/device.h>
61#include <linux/mm.h>
62#include <linux/uaccess.h>
63#include <linux/types.h>
64#include <linux/list.h>
Daniel De Graafbdc612d2011-02-03 12:19:04 -050065#include <linux/highmem.h>
Daniel De Graafdd314052011-02-07 17:23:05 -050066
67#include <xen/xen.h>
68#include <xen/page.h>
69#include <xen/grant_table.h>
70#include <xen/gntalloc.h>
Daniel De Graafbdc612d2011-02-03 12:19:04 -050071#include <xen/events.h>
Daniel De Graafdd314052011-02-07 17:23:05 -050072
73static int limit = 1024;
74module_param(limit, int, 0644);
75MODULE_PARM_DESC(limit, "Maximum number of grants that may be allocated by "
76 "the gntalloc device");
77
78static LIST_HEAD(gref_list);
Daniel De Graaf8ca19a82011-10-27 17:58:48 -040079static DEFINE_MUTEX(gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -050080static int gref_size;
81
Daniel De Graafbdc612d2011-02-03 12:19:04 -050082struct notify_info {
83 uint16_t pgoff:12; /* Bits 0-11: Offset of the byte to clear */
84 uint16_t flags:2; /* Bits 12-13: Unmap notification flags */
85 int event; /* Port (event channel) to notify */
86};
87
Daniel De Graafdd314052011-02-07 17:23:05 -050088/* Metadata on a grant reference. */
89struct gntalloc_gref {
90 struct list_head next_gref; /* list entry gref_list */
91 struct list_head next_file; /* list entry file->list, if open */
92 struct page *page; /* The shared page */
93 uint64_t file_index; /* File offset for mmap() */
94 unsigned int users; /* Use count - when zero, waiting on Xen */
95 grant_ref_t gref_id; /* The grant reference number */
Daniel De Graafbdc612d2011-02-03 12:19:04 -050096 struct notify_info notify; /* Unmap notification */
Daniel De Graafdd314052011-02-07 17:23:05 -050097};
98
99struct gntalloc_file_private_data {
100 struct list_head list;
101 uint64_t index;
102};
103
Daniel De Graaf243082e2011-11-28 11:49:11 -0500104struct gntalloc_vma_private_data {
105 struct gntalloc_gref *gref;
106 int users;
107 int count;
108};
109
Daniel De Graafdd314052011-02-07 17:23:05 -0500110static void __del_gref(struct gntalloc_gref *gref);
111
112static void do_cleanup(void)
113{
114 struct gntalloc_gref *gref, *n;
115 list_for_each_entry_safe(gref, n, &gref_list, next_gref) {
116 if (!gref->users)
117 __del_gref(gref);
118 }
119}
120
121static int add_grefs(struct ioctl_gntalloc_alloc_gref *op,
122 uint32_t *gref_ids, struct gntalloc_file_private_data *priv)
123{
124 int i, rc, readonly;
125 LIST_HEAD(queue_gref);
126 LIST_HEAD(queue_file);
David Vrabel5903c6b2014-09-02 15:21:30 +0100127 struct gntalloc_gref *gref, *next;
Daniel De Graafdd314052011-02-07 17:23:05 -0500128
129 readonly = !(op->flags & GNTALLOC_FLAG_WRITABLE);
130 rc = -ENOMEM;
131 for (i = 0; i < op->count; i++) {
132 gref = kzalloc(sizeof(*gref), GFP_KERNEL);
133 if (!gref)
134 goto undo;
135 list_add_tail(&gref->next_gref, &queue_gref);
136 list_add_tail(&gref->next_file, &queue_file);
137 gref->users = 1;
138 gref->file_index = op->index + i * PAGE_SIZE;
139 gref->page = alloc_page(GFP_KERNEL|__GFP_ZERO);
140 if (!gref->page)
141 goto undo;
142
143 /* Grant foreign access to the page. */
David Vrabele9de2e52014-09-02 15:21:29 +0100144 rc = gnttab_grant_foreign_access(op->domid,
Julien Grall0df4f262015-08-07 17:34:37 +0100145 xen_page_to_gfn(gref->page),
146 readonly);
David Vrabele9de2e52014-09-02 15:21:29 +0100147 if (rc < 0)
Daniel De Graafdd314052011-02-07 17:23:05 -0500148 goto undo;
David Vrabele9de2e52014-09-02 15:21:29 +0100149 gref_ids[i] = gref->gref_id = rc;
Daniel De Graafdd314052011-02-07 17:23:05 -0500150 }
151
152 /* Add to gref lists. */
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400153 mutex_lock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500154 list_splice_tail(&queue_gref, &gref_list);
155 list_splice_tail(&queue_file, &priv->list);
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400156 mutex_unlock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500157
158 return 0;
159
160undo:
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400161 mutex_lock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500162 gref_size -= (op->count - i);
163
David Vrabel5903c6b2014-09-02 15:21:30 +0100164 list_for_each_entry_safe(gref, next, &queue_file, next_file) {
165 list_del(&gref->next_file);
Daniel De Graafdd314052011-02-07 17:23:05 -0500166 __del_gref(gref);
167 }
168
169 /* It's possible for the target domain to map the just-allocated grant
170 * references by blindly guessing their IDs; if this is done, then
171 * __del_gref will leave them in the queue_gref list. They need to be
172 * added to the global list so that we can free them when they are no
173 * longer referenced.
174 */
175 if (unlikely(!list_empty(&queue_gref)))
176 list_splice_tail(&queue_gref, &gref_list);
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400177 mutex_unlock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500178 return rc;
179}
180
181static void __del_gref(struct gntalloc_gref *gref)
182{
Daniel De Graafbdc612d2011-02-03 12:19:04 -0500183 if (gref->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
184 uint8_t *tmp = kmap(gref->page);
185 tmp[gref->notify.pgoff] = 0;
186 kunmap(gref->page);
187 }
Daniel De Graaf0cc678f2011-10-27 17:58:49 -0400188 if (gref->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
Daniel De Graafbdc612d2011-02-03 12:19:04 -0500189 notify_remote_via_evtchn(gref->notify.event);
Daniel De Graaf0cc678f2011-10-27 17:58:49 -0400190 evtchn_put(gref->notify.event);
191 }
Daniel De Graafbdc612d2011-02-03 12:19:04 -0500192
193 gref->notify.flags = 0;
194
David Vrabele9de2e52014-09-02 15:21:29 +0100195 if (gref->gref_id) {
Daniel De Graafdd314052011-02-07 17:23:05 -0500196 if (gnttab_query_foreign_access(gref->gref_id))
197 return;
198
199 if (!gnttab_end_foreign_access_ref(gref->gref_id, 0))
200 return;
Daniel De Graaf0105d2b2011-11-28 11:49:10 -0500201
202 gnttab_free_grant_reference(gref->gref_id);
Daniel De Graafdd314052011-02-07 17:23:05 -0500203 }
204
205 gref_size--;
206 list_del(&gref->next_gref);
207
208 if (gref->page)
209 __free_page(gref->page);
210
211 kfree(gref);
212}
213
214/* finds contiguous grant references in a file, returns the first */
215static struct gntalloc_gref *find_grefs(struct gntalloc_file_private_data *priv,
216 uint64_t index, uint32_t count)
217{
218 struct gntalloc_gref *rv = NULL, *gref;
219 list_for_each_entry(gref, &priv->list, next_file) {
220 if (gref->file_index == index && !rv)
221 rv = gref;
222 if (rv) {
223 if (gref->file_index != index)
224 return NULL;
225 index += PAGE_SIZE;
226 count--;
227 if (count == 0)
228 return rv;
229 }
230 }
231 return NULL;
232}
233
234/*
235 * -------------------------------------
236 * File operations.
237 * -------------------------------------
238 */
239static int gntalloc_open(struct inode *inode, struct file *filp)
240{
241 struct gntalloc_file_private_data *priv;
242
243 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
244 if (!priv)
245 goto out_nomem;
246 INIT_LIST_HEAD(&priv->list);
247
248 filp->private_data = priv;
249
250 pr_debug("%s: priv %p\n", __func__, priv);
251
252 return 0;
253
254out_nomem:
255 return -ENOMEM;
256}
257
258static int gntalloc_release(struct inode *inode, struct file *filp)
259{
260 struct gntalloc_file_private_data *priv = filp->private_data;
261 struct gntalloc_gref *gref;
262
263 pr_debug("%s: priv %p\n", __func__, priv);
264
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400265 mutex_lock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500266 while (!list_empty(&priv->list)) {
267 gref = list_entry(priv->list.next,
268 struct gntalloc_gref, next_file);
269 list_del(&gref->next_file);
270 gref->users--;
271 if (gref->users == 0)
272 __del_gref(gref);
273 }
274 kfree(priv);
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400275 mutex_unlock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500276
277 return 0;
278}
279
280static long gntalloc_ioctl_alloc(struct gntalloc_file_private_data *priv,
281 struct ioctl_gntalloc_alloc_gref __user *arg)
282{
283 int rc = 0;
284 struct ioctl_gntalloc_alloc_gref op;
285 uint32_t *gref_ids;
286
287 pr_debug("%s: priv %p\n", __func__, priv);
288
289 if (copy_from_user(&op, arg, sizeof(op))) {
290 rc = -EFAULT;
291 goto out;
292 }
293
Dan Carpenter21643e62011-11-04 21:24:08 +0300294 gref_ids = kcalloc(op.count, sizeof(gref_ids[0]), GFP_TEMPORARY);
Daniel De Graafdd314052011-02-07 17:23:05 -0500295 if (!gref_ids) {
296 rc = -ENOMEM;
297 goto out;
298 }
299
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400300 mutex_lock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500301 /* Clean up pages that were at zero (local) users but were still mapped
302 * by remote domains. Since those pages count towards the limit that we
303 * are about to enforce, removing them here is a good idea.
304 */
305 do_cleanup();
306 if (gref_size + op.count > limit) {
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400307 mutex_unlock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500308 rc = -ENOSPC;
309 goto out_free;
310 }
311 gref_size += op.count;
312 op.index = priv->index;
313 priv->index += op.count * PAGE_SIZE;
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400314 mutex_unlock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500315
316 rc = add_grefs(&op, gref_ids, priv);
317 if (rc < 0)
318 goto out_free;
319
320 /* Once we finish add_grefs, it is unsafe to touch the new reference,
321 * since it is possible for a concurrent ioctl to remove it (by guessing
322 * its index). If the userspace application doesn't provide valid memory
323 * to write the IDs to, then it will need to close the file in order to
324 * release - which it will do by segfaulting when it tries to access the
325 * IDs to close them.
326 */
327 if (copy_to_user(arg, &op, sizeof(op))) {
328 rc = -EFAULT;
329 goto out_free;
330 }
331 if (copy_to_user(arg->gref_ids, gref_ids,
332 sizeof(gref_ids[0]) * op.count)) {
333 rc = -EFAULT;
334 goto out_free;
335 }
336
337out_free:
338 kfree(gref_ids);
339out:
340 return rc;
341}
342
343static long gntalloc_ioctl_dealloc(struct gntalloc_file_private_data *priv,
344 void __user *arg)
345{
346 int i, rc = 0;
347 struct ioctl_gntalloc_dealloc_gref op;
348 struct gntalloc_gref *gref, *n;
349
350 pr_debug("%s: priv %p\n", __func__, priv);
351
352 if (copy_from_user(&op, arg, sizeof(op))) {
353 rc = -EFAULT;
354 goto dealloc_grant_out;
355 }
356
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400357 mutex_lock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500358 gref = find_grefs(priv, op.index, op.count);
359 if (gref) {
360 /* Remove from the file list only, and decrease reference count.
361 * The later call to do_cleanup() will remove from gref_list and
362 * free the memory if the pages aren't mapped anywhere.
363 */
364 for (i = 0; i < op.count; i++) {
365 n = list_entry(gref->next_file.next,
366 struct gntalloc_gref, next_file);
367 list_del(&gref->next_file);
368 gref->users--;
369 gref = n;
370 }
371 } else {
372 rc = -EINVAL;
373 }
374
375 do_cleanup();
376
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400377 mutex_unlock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500378dealloc_grant_out:
379 return rc;
380}
381
Daniel De Graafbdc612d2011-02-03 12:19:04 -0500382static long gntalloc_ioctl_unmap_notify(struct gntalloc_file_private_data *priv,
383 void __user *arg)
384{
385 struct ioctl_gntalloc_unmap_notify op;
386 struct gntalloc_gref *gref;
387 uint64_t index;
388 int pgoff;
389 int rc;
390
391 if (copy_from_user(&op, arg, sizeof(op)))
392 return -EFAULT;
393
394 index = op.index & ~(PAGE_SIZE - 1);
395 pgoff = op.index & (PAGE_SIZE - 1);
396
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400397 mutex_lock(&gref_mutex);
Daniel De Graafbdc612d2011-02-03 12:19:04 -0500398
399 gref = find_grefs(priv, index, 1);
400 if (!gref) {
401 rc = -ENOENT;
402 goto unlock_out;
403 }
404
405 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) {
406 rc = -EINVAL;
407 goto unlock_out;
408 }
409
Daniel De Graaf0cc678f2011-10-27 17:58:49 -0400410 /* We need to grab a reference to the event channel we are going to use
411 * to send the notify before releasing the reference we may already have
412 * (if someone has called this ioctl twice). This is required so that
413 * it is possible to change the clear_byte part of the notification
414 * without disturbing the event channel part, which may now be the last
415 * reference to that event channel.
416 */
417 if (op.action & UNMAP_NOTIFY_SEND_EVENT) {
418 if (evtchn_get(op.event_channel_port)) {
419 rc = -EINVAL;
420 goto unlock_out;
421 }
422 }
423
424 if (gref->notify.flags & UNMAP_NOTIFY_SEND_EVENT)
425 evtchn_put(gref->notify.event);
426
Daniel De Graafbdc612d2011-02-03 12:19:04 -0500427 gref->notify.flags = op.action;
428 gref->notify.pgoff = pgoff;
429 gref->notify.event = op.event_channel_port;
430 rc = 0;
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400431
Daniel De Graafbdc612d2011-02-03 12:19:04 -0500432 unlock_out:
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400433 mutex_unlock(&gref_mutex);
Daniel De Graafbdc612d2011-02-03 12:19:04 -0500434 return rc;
435}
436
Daniel De Graafdd314052011-02-07 17:23:05 -0500437static long gntalloc_ioctl(struct file *filp, unsigned int cmd,
438 unsigned long arg)
439{
440 struct gntalloc_file_private_data *priv = filp->private_data;
441
442 switch (cmd) {
443 case IOCTL_GNTALLOC_ALLOC_GREF:
444 return gntalloc_ioctl_alloc(priv, (void __user *)arg);
445
446 case IOCTL_GNTALLOC_DEALLOC_GREF:
447 return gntalloc_ioctl_dealloc(priv, (void __user *)arg);
448
Daniel De Graafbdc612d2011-02-03 12:19:04 -0500449 case IOCTL_GNTALLOC_SET_UNMAP_NOTIFY:
450 return gntalloc_ioctl_unmap_notify(priv, (void __user *)arg);
451
Daniel De Graafdd314052011-02-07 17:23:05 -0500452 default:
453 return -ENOIOCTLCMD;
454 }
455
456 return 0;
457}
458
Daniel De Graafd79647a2011-03-07 15:18:57 -0500459static void gntalloc_vma_open(struct vm_area_struct *vma)
460{
Daniel De Graaf243082e2011-11-28 11:49:11 -0500461 struct gntalloc_vma_private_data *priv = vma->vm_private_data;
462
463 if (!priv)
Daniel De Graafd79647a2011-03-07 15:18:57 -0500464 return;
465
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400466 mutex_lock(&gref_mutex);
Daniel De Graaf243082e2011-11-28 11:49:11 -0500467 priv->users++;
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400468 mutex_unlock(&gref_mutex);
Daniel De Graafd79647a2011-03-07 15:18:57 -0500469}
470
Daniel De Graafdd314052011-02-07 17:23:05 -0500471static void gntalloc_vma_close(struct vm_area_struct *vma)
472{
Daniel De Graaf243082e2011-11-28 11:49:11 -0500473 struct gntalloc_vma_private_data *priv = vma->vm_private_data;
474 struct gntalloc_gref *gref, *next;
475 int i;
476
477 if (!priv)
Daniel De Graafdd314052011-02-07 17:23:05 -0500478 return;
479
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400480 mutex_lock(&gref_mutex);
Daniel De Graaf243082e2011-11-28 11:49:11 -0500481 priv->users--;
482 if (priv->users == 0) {
483 gref = priv->gref;
484 for (i = 0; i < priv->count; i++) {
485 gref->users--;
486 next = list_entry(gref->next_gref.next,
487 struct gntalloc_gref, next_gref);
488 if (gref->users == 0)
489 __del_gref(gref);
490 gref = next;
491 }
492 kfree(priv);
493 }
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400494 mutex_unlock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500495}
496
Kirill A. Shutemov7cbea8d2015-09-09 15:39:26 -0700497static const struct vm_operations_struct gntalloc_vmops = {
Daniel De Graafd79647a2011-03-07 15:18:57 -0500498 .open = gntalloc_vma_open,
Daniel De Graafdd314052011-02-07 17:23:05 -0500499 .close = gntalloc_vma_close,
500};
501
502static int gntalloc_mmap(struct file *filp, struct vm_area_struct *vma)
503{
504 struct gntalloc_file_private_data *priv = filp->private_data;
Daniel De Graaf243082e2011-11-28 11:49:11 -0500505 struct gntalloc_vma_private_data *vm_priv;
Daniel De Graafdd314052011-02-07 17:23:05 -0500506 struct gntalloc_gref *gref;
507 int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
508 int rv, i;
509
Daniel De Graafdd314052011-02-07 17:23:05 -0500510 if (!(vma->vm_flags & VM_SHARED)) {
Joe Perches283c0972013-06-28 03:21:41 -0700511 pr_err("%s: Mapping must be shared\n", __func__);
Daniel De Graafdd314052011-02-07 17:23:05 -0500512 return -EINVAL;
513 }
514
Daniel De Graaf243082e2011-11-28 11:49:11 -0500515 vm_priv = kmalloc(sizeof(*vm_priv), GFP_KERNEL);
516 if (!vm_priv)
517 return -ENOMEM;
518
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400519 mutex_lock(&gref_mutex);
Daniel De Graaf243082e2011-11-28 11:49:11 -0500520
521 pr_debug("%s: priv %p,%p, page %lu+%d\n", __func__,
522 priv, vm_priv, vma->vm_pgoff, count);
523
Daniel De Graafdd314052011-02-07 17:23:05 -0500524 gref = find_grefs(priv, vma->vm_pgoff << PAGE_SHIFT, count);
525 if (gref == NULL) {
526 rv = -ENOENT;
527 pr_debug("%s: Could not find grant reference",
528 __func__);
Julia Lawall2e163412011-12-23 18:39:29 +0100529 kfree(vm_priv);
Daniel De Graafdd314052011-02-07 17:23:05 -0500530 goto out_unlock;
531 }
532
Daniel De Graaf243082e2011-11-28 11:49:11 -0500533 vm_priv->gref = gref;
534 vm_priv->users = 1;
535 vm_priv->count = count;
Daniel De Graafdd314052011-02-07 17:23:05 -0500536
Daniel De Graaf243082e2011-11-28 11:49:11 -0500537 vma->vm_private_data = vm_priv;
538
Konstantin Khlebnikov314e51b2012-10-08 16:29:02 -0700539 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
Daniel De Graafdd314052011-02-07 17:23:05 -0500540
541 vma->vm_ops = &gntalloc_vmops;
542
543 for (i = 0; i < count; i++) {
544 gref->users++;
545 rv = vm_insert_page(vma, vma->vm_start + i * PAGE_SIZE,
546 gref->page);
547 if (rv)
548 goto out_unlock;
549
550 gref = list_entry(gref->next_file.next,
551 struct gntalloc_gref, next_file);
552 }
553 rv = 0;
554
555out_unlock:
Daniel De Graaf8ca19a82011-10-27 17:58:48 -0400556 mutex_unlock(&gref_mutex);
Daniel De Graafdd314052011-02-07 17:23:05 -0500557 return rv;
558}
559
560static const struct file_operations gntalloc_fops = {
561 .owner = THIS_MODULE,
562 .open = gntalloc_open,
563 .release = gntalloc_release,
564 .unlocked_ioctl = gntalloc_ioctl,
565 .mmap = gntalloc_mmap
566};
567
568/*
569 * -------------------------------------
570 * Module creation/destruction.
571 * -------------------------------------
572 */
573static struct miscdevice gntalloc_miscdev = {
574 .minor = MISC_DYNAMIC_MINOR,
575 .name = "xen/gntalloc",
576 .fops = &gntalloc_fops,
577};
578
579static int __init gntalloc_init(void)
580{
581 int err;
582
583 if (!xen_domain())
584 return -ENODEV;
585
586 err = misc_register(&gntalloc_miscdev);
587 if (err != 0) {
Joe Perches283c0972013-06-28 03:21:41 -0700588 pr_err("Could not register misc gntalloc device\n");
Daniel De Graafdd314052011-02-07 17:23:05 -0500589 return err;
590 }
591
592 pr_debug("Created grant allocation device at %d,%d\n",
593 MISC_MAJOR, gntalloc_miscdev.minor);
594
595 return 0;
596}
597
598static void __exit gntalloc_exit(void)
599{
600 misc_deregister(&gntalloc_miscdev);
601}
602
603module_init(gntalloc_init);
604module_exit(gntalloc_exit);
605
606MODULE_LICENSE("GPL");
607MODULE_AUTHOR("Carter Weatherly <carter.weatherly@jhuapl.edu>, "
608 "Daniel De Graaf <dgdegra@tycho.nsa.gov>");
609MODULE_DESCRIPTION("User-space grant reference allocator driver");