1 /******************************************************************************
2 * privcmd.c
3 *
4 * Interface to privileged domain-0 commands.
5 *
6 * Copyright (c) 2002-2004, K A Fraser, B Dragovic
7 */
8
9 #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
10
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/sched.h>
14 #include <linux/slab.h>
15 #include <linux/string.h>
16 #include <linux/errno.h>
17 #include <linux/mm.h>
18 #include <linux/mman.h>
19 #include <linux/uaccess.h>
20 #include <linux/swap.h>
21 #include <linux/highmem.h>
22 #include <linux/pagemap.h>
23 #include <linux/seq_file.h>
24 #include <linux/miscdevice.h>
25 #include <linux/moduleparam.h>
26
27 #include <asm/pgalloc.h>
28 #include <asm/pgtable.h>
29 #include <asm/tlb.h>
30 #include <asm/xen/hypervisor.h>
31 #include <asm/xen/hypercall.h>
32
33 #include <xen/xen.h>
34 #include <xen/privcmd.h>
35 #include <xen/interface/xen.h>
36 #include <xen/interface/memory.h>
37 #include <xen/interface/hvm/dm_op.h>
38 #include <xen/features.h>
39 #include <xen/page.h>
40 #include <xen/xen-ops.h>
41 #include <xen/balloon.h>
42
43 #include "privcmd.h"
44
45 MODULE_LICENSE("GPL");
46
47 #define PRIV_VMA_LOCKED ((void *)1)
48
49 static unsigned int privcmd_dm_op_max_num = 16;
50 module_param_named(dm_op_max_nr_bufs, privcmd_dm_op_max_num, uint, 0644);
51 MODULE_PARM_DESC(dm_op_max_nr_bufs,
52 "Maximum number of buffers per dm_op hypercall");
53
54 static unsigned int privcmd_dm_op_buf_max_size = 4096;
55 module_param_named(dm_op_buf_max_size, privcmd_dm_op_buf_max_size, uint,
56 0644);
57 MODULE_PARM_DESC(dm_op_buf_max_size,
58 "Maximum size of a dm_op hypercall buffer");
59
60 struct privcmd_data {
61 domid_t domid;
62 };
63
64 static int privcmd_vma_range_is_mapped(
65 struct vm_area_struct *vma,
66 unsigned long addr,
67 unsigned long nr_pages);
68
privcmd_ioctl_hypercall(struct file * file,void __user * udata)69 static long privcmd_ioctl_hypercall(struct file *file, void __user *udata)
70 {
71 struct privcmd_data *data = file->private_data;
72 struct privcmd_hypercall hypercall;
73 long ret;
74
75 /* Disallow arbitrary hypercalls if restricted */
76 if (data->domid != DOMID_INVALID)
77 return -EPERM;
78
79 if (copy_from_user(&hypercall, udata, sizeof(hypercall)))
80 return -EFAULT;
81
82 xen_preemptible_hcall_begin();
83 ret = privcmd_call(hypercall.op,
84 hypercall.arg[0], hypercall.arg[1],
85 hypercall.arg[2], hypercall.arg[3],
86 hypercall.arg[4]);
87 xen_preemptible_hcall_end();
88
89 return ret;
90 }
91
free_page_list(struct list_head * pages)92 static void free_page_list(struct list_head *pages)
93 {
94 struct page *p, *n;
95
96 list_for_each_entry_safe(p, n, pages, lru)
97 __free_page(p);
98
99 INIT_LIST_HEAD(pages);
100 }
101
102 /*
103 * Given an array of items in userspace, return a list of pages
104 * containing the data. If copying fails, either because of memory
105 * allocation failure or a problem reading user memory, return an
106 * error code; its up to the caller to dispose of any partial list.
107 */
gather_array(struct list_head * pagelist,unsigned nelem,size_t size,const void __user * data)108 static int gather_array(struct list_head *pagelist,
109 unsigned nelem, size_t size,
110 const void __user *data)
111 {
112 unsigned pageidx;
113 void *pagedata;
114 int ret;
115
116 if (size > PAGE_SIZE)
117 return 0;
118
119 pageidx = PAGE_SIZE;
120 pagedata = NULL; /* quiet, gcc */
121 while (nelem--) {
122 if (pageidx > PAGE_SIZE-size) {
123 struct page *page = alloc_page(GFP_KERNEL);
124
125 ret = -ENOMEM;
126 if (page == NULL)
127 goto fail;
128
129 pagedata = page_address(page);
130
131 list_add_tail(&page->lru, pagelist);
132 pageidx = 0;
133 }
134
135 ret = -EFAULT;
136 if (copy_from_user(pagedata + pageidx, data, size))
137 goto fail;
138
139 data += size;
140 pageidx += size;
141 }
142
143 ret = 0;
144
145 fail:
146 return ret;
147 }
148
149 /*
150 * Call function "fn" on each element of the array fragmented
151 * over a list of pages.
152 */
traverse_pages(unsigned nelem,size_t size,struct list_head * pos,int (* fn)(void * data,void * state),void * state)153 static int traverse_pages(unsigned nelem, size_t size,
154 struct list_head *pos,
155 int (*fn)(void *data, void *state),
156 void *state)
157 {
158 void *pagedata;
159 unsigned pageidx;
160 int ret = 0;
161
162 BUG_ON(size > PAGE_SIZE);
163
164 pageidx = PAGE_SIZE;
165 pagedata = NULL; /* hush, gcc */
166
167 while (nelem--) {
168 if (pageidx > PAGE_SIZE-size) {
169 struct page *page;
170 pos = pos->next;
171 page = list_entry(pos, struct page, lru);
172 pagedata = page_address(page);
173 pageidx = 0;
174 }
175
176 ret = (*fn)(pagedata + pageidx, state);
177 if (ret)
178 break;
179 pageidx += size;
180 }
181
182 return ret;
183 }
184
185 /*
186 * Similar to traverse_pages, but use each page as a "block" of
187 * data to be processed as one unit.
188 */
traverse_pages_block(unsigned nelem,size_t size,struct list_head * pos,int (* fn)(void * data,int nr,void * state),void * state)189 static int traverse_pages_block(unsigned nelem, size_t size,
190 struct list_head *pos,
191 int (*fn)(void *data, int nr, void *state),
192 void *state)
193 {
194 void *pagedata;
195 int ret = 0;
196
197 BUG_ON(size > PAGE_SIZE);
198
199 while (nelem) {
200 int nr = (PAGE_SIZE/size);
201 struct page *page;
202 if (nr > nelem)
203 nr = nelem;
204 pos = pos->next;
205 page = list_entry(pos, struct page, lru);
206 pagedata = page_address(page);
207 ret = (*fn)(pagedata, nr, state);
208 if (ret)
209 break;
210 nelem -= nr;
211 }
212
213 return ret;
214 }
215
216 struct mmap_gfn_state {
217 unsigned long va;
218 struct vm_area_struct *vma;
219 domid_t domain;
220 };
221
mmap_gfn_range(void * data,void * state)222 static int mmap_gfn_range(void *data, void *state)
223 {
224 struct privcmd_mmap_entry *msg = data;
225 struct mmap_gfn_state *st = state;
226 struct vm_area_struct *vma = st->vma;
227 int rc;
228
229 /* Do not allow range to wrap the address space. */
230 if ((msg->npages > (LONG_MAX >> PAGE_SHIFT)) ||
231 ((unsigned long)(msg->npages << PAGE_SHIFT) >= -st->va))
232 return -EINVAL;
233
234 /* Range chunks must be contiguous in va space. */
235 if ((msg->va != st->va) ||
236 ((msg->va+(msg->npages<<PAGE_SHIFT)) > vma->vm_end))
237 return -EINVAL;
238
239 rc = xen_remap_domain_gfn_range(vma,
240 msg->va & PAGE_MASK,
241 msg->mfn, msg->npages,
242 vma->vm_page_prot,
243 st->domain, NULL);
244 if (rc < 0)
245 return rc;
246
247 st->va += msg->npages << PAGE_SHIFT;
248
249 return 0;
250 }
251
privcmd_ioctl_mmap(struct file * file,void __user * udata)252 static long privcmd_ioctl_mmap(struct file *file, void __user *udata)
253 {
254 struct privcmd_data *data = file->private_data;
255 struct privcmd_mmap mmapcmd;
256 struct mm_struct *mm = current->mm;
257 struct vm_area_struct *vma;
258 int rc;
259 LIST_HEAD(pagelist);
260 struct mmap_gfn_state state;
261
262 /* We only support privcmd_ioctl_mmap_batch for auto translated. */
263 if (xen_feature(XENFEAT_auto_translated_physmap))
264 return -ENOSYS;
265
266 if (copy_from_user(&mmapcmd, udata, sizeof(mmapcmd)))
267 return -EFAULT;
268
269 /* If restriction is in place, check the domid matches */
270 if (data->domid != DOMID_INVALID && data->domid != mmapcmd.dom)
271 return -EPERM;
272
273 rc = gather_array(&pagelist,
274 mmapcmd.num, sizeof(struct privcmd_mmap_entry),
275 mmapcmd.entry);
276
277 if (rc || list_empty(&pagelist))
278 goto out;
279
280 down_write(&mm->mmap_sem);
281
282 {
283 struct page *page = list_first_entry(&pagelist,
284 struct page, lru);
285 struct privcmd_mmap_entry *msg = page_address(page);
286
287 vma = find_vma(mm, msg->va);
288 rc = -EINVAL;
289
290 if (!vma || (msg->va != vma->vm_start) || vma->vm_private_data)
291 goto out_up;
292 vma->vm_private_data = PRIV_VMA_LOCKED;
293 }
294
295 state.va = vma->vm_start;
296 state.vma = vma;
297 state.domain = mmapcmd.dom;
298
299 rc = traverse_pages(mmapcmd.num, sizeof(struct privcmd_mmap_entry),
300 &pagelist,
301 mmap_gfn_range, &state);
302
303
304 out_up:
305 up_write(&mm->mmap_sem);
306
307 out:
308 free_page_list(&pagelist);
309
310 return rc;
311 }
312
313 struct mmap_batch_state {
314 domid_t domain;
315 unsigned long va;
316 struct vm_area_struct *vma;
317 int index;
318 /* A tristate:
319 * 0 for no errors
320 * 1 if at least one error has happened (and no
321 * -ENOENT errors have happened)
322 * -ENOENT if at least 1 -ENOENT has happened.
323 */
324 int global_error;
325 int version;
326
327 /* User-space gfn array to store errors in the second pass for V1. */
328 xen_pfn_t __user *user_gfn;
329 /* User-space int array to store errors in the second pass for V2. */
330 int __user *user_err;
331 };
332
333 /* auto translated dom0 note: if domU being created is PV, then gfn is
334 * mfn(addr on bus). If it's auto xlated, then gfn is pfn (input to HAP).
335 */
mmap_batch_fn(void * data,int nr,void * state)336 static int mmap_batch_fn(void *data, int nr, void *state)
337 {
338 xen_pfn_t *gfnp = data;
339 struct mmap_batch_state *st = state;
340 struct vm_area_struct *vma = st->vma;
341 struct page **pages = vma->vm_private_data;
342 struct page **cur_pages = NULL;
343 int ret;
344
345 if (xen_feature(XENFEAT_auto_translated_physmap))
346 cur_pages = &pages[st->index];
347
348 BUG_ON(nr < 0);
349 ret = xen_remap_domain_gfn_array(st->vma, st->va & PAGE_MASK, gfnp, nr,
350 (int *)gfnp, st->vma->vm_page_prot,
351 st->domain, cur_pages);
352
353 /* Adjust the global_error? */
354 if (ret != nr) {
355 if (ret == -ENOENT)
356 st->global_error = -ENOENT;
357 else {
358 /* Record that at least one error has happened. */
359 if (st->global_error == 0)
360 st->global_error = 1;
361 }
362 }
363 st->va += XEN_PAGE_SIZE * nr;
364 st->index += nr / XEN_PFN_PER_PAGE;
365
366 return 0;
367 }
368
mmap_return_error(int err,struct mmap_batch_state * st)369 static int mmap_return_error(int err, struct mmap_batch_state *st)
370 {
371 int ret;
372
373 if (st->version == 1) {
374 if (err) {
375 xen_pfn_t gfn;
376
377 ret = get_user(gfn, st->user_gfn);
378 if (ret < 0)
379 return ret;
380 /*
381 * V1 encodes the error codes in the 32bit top
382 * nibble of the gfn (with its known
383 * limitations vis-a-vis 64 bit callers).
384 */
385 gfn |= (err == -ENOENT) ?
386 PRIVCMD_MMAPBATCH_PAGED_ERROR :
387 PRIVCMD_MMAPBATCH_MFN_ERROR;
388 return __put_user(gfn, st->user_gfn++);
389 } else
390 st->user_gfn++;
391 } else { /* st->version == 2 */
392 if (err)
393 return __put_user(err, st->user_err++);
394 else
395 st->user_err++;
396 }
397
398 return 0;
399 }
400
mmap_return_errors(void * data,int nr,void * state)401 static int mmap_return_errors(void *data, int nr, void *state)
402 {
403 struct mmap_batch_state *st = state;
404 int *errs = data;
405 int i;
406 int ret;
407
408 for (i = 0; i < nr; i++) {
409 ret = mmap_return_error(errs[i], st);
410 if (ret < 0)
411 return ret;
412 }
413 return 0;
414 }
415
416 /* Allocate pfns that are then mapped with gfns from foreign domid. Update
417 * the vma with the page info to use later.
418 * Returns: 0 if success, otherwise -errno
419 */
alloc_empty_pages(struct vm_area_struct * vma,int numpgs)420 static int alloc_empty_pages(struct vm_area_struct *vma, int numpgs)
421 {
422 int rc;
423 struct page **pages;
424
425 pages = kcalloc(numpgs, sizeof(pages[0]), GFP_KERNEL);
426 if (pages == NULL)
427 return -ENOMEM;
428
429 rc = alloc_xenballooned_pages(numpgs, pages);
430 if (rc != 0) {
431 pr_warn("%s Could not alloc %d pfns rc:%d\n", __func__,
432 numpgs, rc);
433 kfree(pages);
434 return -ENOMEM;
435 }
436 BUG_ON(vma->vm_private_data != NULL);
437 vma->vm_private_data = pages;
438
439 return 0;
440 }
441
442 static const struct vm_operations_struct privcmd_vm_ops;
443
privcmd_ioctl_mmap_batch(struct file * file,void __user * udata,int version)444 static long privcmd_ioctl_mmap_batch(
445 struct file *file, void __user *udata, int version)
446 {
447 struct privcmd_data *data = file->private_data;
448 int ret;
449 struct privcmd_mmapbatch_v2 m;
450 struct mm_struct *mm = current->mm;
451 struct vm_area_struct *vma;
452 unsigned long nr_pages;
453 LIST_HEAD(pagelist);
454 struct mmap_batch_state state;
455
456 switch (version) {
457 case 1:
458 if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch)))
459 return -EFAULT;
460 /* Returns per-frame error in m.arr. */
461 m.err = NULL;
462 if (!access_ok(VERIFY_WRITE, m.arr, m.num * sizeof(*m.arr)))
463 return -EFAULT;
464 break;
465 case 2:
466 if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch_v2)))
467 return -EFAULT;
468 /* Returns per-frame error code in m.err. */
469 if (!access_ok(VERIFY_WRITE, m.err, m.num * (sizeof(*m.err))))
470 return -EFAULT;
471 break;
472 default:
473 return -EINVAL;
474 }
475
476 /* If restriction is in place, check the domid matches */
477 if (data->domid != DOMID_INVALID && data->domid != m.dom)
478 return -EPERM;
479
480 nr_pages = DIV_ROUND_UP(m.num, XEN_PFN_PER_PAGE);
481 if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
482 return -EINVAL;
483
484 ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t), m.arr);
485
486 if (ret)
487 goto out;
488 if (list_empty(&pagelist)) {
489 ret = -EINVAL;
490 goto out;
491 }
492
493 if (version == 2) {
494 /* Zero error array now to only copy back actual errors. */
495 if (clear_user(m.err, sizeof(int) * m.num)) {
496 ret = -EFAULT;
497 goto out;
498 }
499 }
500
501 down_write(&mm->mmap_sem);
502
503 vma = find_vma(mm, m.addr);
504 if (!vma ||
505 vma->vm_ops != &privcmd_vm_ops) {
506 ret = -EINVAL;
507 goto out_unlock;
508 }
509
510 /*
511 * Caller must either:
512 *
513 * Map the whole VMA range, which will also allocate all the
514 * pages required for the auto_translated_physmap case.
515 *
516 * Or
517 *
518 * Map unmapped holes left from a previous map attempt (e.g.,
519 * because those foreign frames were previously paged out).
520 */
521 if (vma->vm_private_data == NULL) {
522 if (m.addr != vma->vm_start ||
523 m.addr + (nr_pages << PAGE_SHIFT) != vma->vm_end) {
524 ret = -EINVAL;
525 goto out_unlock;
526 }
527 if (xen_feature(XENFEAT_auto_translated_physmap)) {
528 ret = alloc_empty_pages(vma, nr_pages);
529 if (ret < 0)
530 goto out_unlock;
531 } else
532 vma->vm_private_data = PRIV_VMA_LOCKED;
533 } else {
534 if (m.addr < vma->vm_start ||
535 m.addr + (nr_pages << PAGE_SHIFT) > vma->vm_end) {
536 ret = -EINVAL;
537 goto out_unlock;
538 }
539 if (privcmd_vma_range_is_mapped(vma, m.addr, nr_pages)) {
540 ret = -EINVAL;
541 goto out_unlock;
542 }
543 }
544
545 state.domain = m.dom;
546 state.vma = vma;
547 state.va = m.addr;
548 state.index = 0;
549 state.global_error = 0;
550 state.version = version;
551
552 BUILD_BUG_ON(((PAGE_SIZE / sizeof(xen_pfn_t)) % XEN_PFN_PER_PAGE) != 0);
553 /* mmap_batch_fn guarantees ret == 0 */
554 BUG_ON(traverse_pages_block(m.num, sizeof(xen_pfn_t),
555 &pagelist, mmap_batch_fn, &state));
556
557 up_write(&mm->mmap_sem);
558
559 if (state.global_error) {
560 /* Write back errors in second pass. */
561 state.user_gfn = (xen_pfn_t *)m.arr;
562 state.user_err = m.err;
563 ret = traverse_pages_block(m.num, sizeof(xen_pfn_t),
564 &pagelist, mmap_return_errors, &state);
565 } else
566 ret = 0;
567
568 /* If we have not had any EFAULT-like global errors then set the global
569 * error to -ENOENT if necessary. */
570 if ((ret == 0) && (state.global_error == -ENOENT))
571 ret = -ENOENT;
572
573 out:
574 free_page_list(&pagelist);
575 return ret;
576
577 out_unlock:
578 up_write(&mm->mmap_sem);
579 goto out;
580 }
581
lock_pages(struct privcmd_dm_op_buf kbufs[],unsigned int num,struct page * pages[],unsigned int nr_pages)582 static int lock_pages(
583 struct privcmd_dm_op_buf kbufs[], unsigned int num,
584 struct page *pages[], unsigned int nr_pages)
585 {
586 unsigned int i;
587
588 for (i = 0; i < num; i++) {
589 unsigned int requested;
590 int pinned;
591
592 requested = DIV_ROUND_UP(
593 offset_in_page(kbufs[i].uptr) + kbufs[i].size,
594 PAGE_SIZE);
595 if (requested > nr_pages)
596 return -ENOSPC;
597
598 pinned = get_user_pages_fast(
599 (unsigned long) kbufs[i].uptr,
600 requested, FOLL_WRITE, pages);
601 if (pinned < 0)
602 return pinned;
603
604 nr_pages -= pinned;
605 pages += pinned;
606 }
607
608 return 0;
609 }
610
unlock_pages(struct page * pages[],unsigned int nr_pages)611 static void unlock_pages(struct page *pages[], unsigned int nr_pages)
612 {
613 unsigned int i;
614
615 if (!pages)
616 return;
617
618 for (i = 0; i < nr_pages; i++) {
619 if (pages[i])
620 put_page(pages[i]);
621 }
622 }
623
privcmd_ioctl_dm_op(struct file * file,void __user * udata)624 static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
625 {
626 struct privcmd_data *data = file->private_data;
627 struct privcmd_dm_op kdata;
628 struct privcmd_dm_op_buf *kbufs;
629 unsigned int nr_pages = 0;
630 struct page **pages = NULL;
631 struct xen_dm_op_buf *xbufs = NULL;
632 unsigned int i;
633 long rc;
634
635 if (copy_from_user(&kdata, udata, sizeof(kdata)))
636 return -EFAULT;
637
638 /* If restriction is in place, check the domid matches */
639 if (data->domid != DOMID_INVALID && data->domid != kdata.dom)
640 return -EPERM;
641
642 if (kdata.num == 0)
643 return 0;
644
645 if (kdata.num > privcmd_dm_op_max_num)
646 return -E2BIG;
647
648 kbufs = kcalloc(kdata.num, sizeof(*kbufs), GFP_KERNEL);
649 if (!kbufs)
650 return -ENOMEM;
651
652 if (copy_from_user(kbufs, kdata.ubufs,
653 sizeof(*kbufs) * kdata.num)) {
654 rc = -EFAULT;
655 goto out;
656 }
657
658 for (i = 0; i < kdata.num; i++) {
659 if (kbufs[i].size > privcmd_dm_op_buf_max_size) {
660 rc = -E2BIG;
661 goto out;
662 }
663
664 if (!access_ok(VERIFY_WRITE, kbufs[i].uptr,
665 kbufs[i].size)) {
666 rc = -EFAULT;
667 goto out;
668 }
669
670 nr_pages += DIV_ROUND_UP(
671 offset_in_page(kbufs[i].uptr) + kbufs[i].size,
672 PAGE_SIZE);
673 }
674
675 pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL);
676 if (!pages) {
677 rc = -ENOMEM;
678 goto out;
679 }
680
681 xbufs = kcalloc(kdata.num, sizeof(*xbufs), GFP_KERNEL);
682 if (!xbufs) {
683 rc = -ENOMEM;
684 goto out;
685 }
686
687 rc = lock_pages(kbufs, kdata.num, pages, nr_pages);
688 if (rc)
689 goto out;
690
691 for (i = 0; i < kdata.num; i++) {
692 set_xen_guest_handle(xbufs[i].h, kbufs[i].uptr);
693 xbufs[i].size = kbufs[i].size;
694 }
695
696 xen_preemptible_hcall_begin();
697 rc = HYPERVISOR_dm_op(kdata.dom, kdata.num, xbufs);
698 xen_preemptible_hcall_end();
699
700 out:
701 unlock_pages(pages, nr_pages);
702 kfree(xbufs);
703 kfree(pages);
704 kfree(kbufs);
705
706 return rc;
707 }
708
privcmd_ioctl_restrict(struct file * file,void __user * udata)709 static long privcmd_ioctl_restrict(struct file *file, void __user *udata)
710 {
711 struct privcmd_data *data = file->private_data;
712 domid_t dom;
713
714 if (copy_from_user(&dom, udata, sizeof(dom)))
715 return -EFAULT;
716
717 /* Set restriction to the specified domain, or check it matches */
718 if (data->domid == DOMID_INVALID)
719 data->domid = dom;
720 else if (data->domid != dom)
721 return -EINVAL;
722
723 return 0;
724 }
725
726 struct remap_pfn {
727 struct mm_struct *mm;
728 struct page **pages;
729 pgprot_t prot;
730 unsigned long i;
731 };
732
remap_pfn_fn(pte_t * ptep,pgtable_t token,unsigned long addr,void * data)733 static int remap_pfn_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
734 void *data)
735 {
736 struct remap_pfn *r = data;
737 struct page *page = r->pages[r->i];
738 pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), r->prot));
739
740 set_pte_at(r->mm, addr, ptep, pte);
741 r->i++;
742
743 return 0;
744 }
745
privcmd_ioctl_mmap_resource(struct file * file,struct privcmd_mmap_resource __user * udata)746 static long privcmd_ioctl_mmap_resource(struct file *file,
747 struct privcmd_mmap_resource __user *udata)
748 {
749 struct privcmd_data *data = file->private_data;
750 struct mm_struct *mm = current->mm;
751 struct vm_area_struct *vma;
752 struct privcmd_mmap_resource kdata;
753 xen_pfn_t *pfns = NULL;
754 struct xen_mem_acquire_resource xdata = { };
755 int rc;
756
757 if (copy_from_user(&kdata, udata, sizeof(kdata)))
758 return -EFAULT;
759
760 /* If restriction is in place, check the domid matches */
761 if (data->domid != DOMID_INVALID && data->domid != kdata.dom)
762 return -EPERM;
763
764 /* Both fields must be set or unset */
765 if (!!kdata.addr != !!kdata.num)
766 return -EINVAL;
767
768 xdata.domid = kdata.dom;
769 xdata.type = kdata.type;
770 xdata.id = kdata.id;
771
772 if (!kdata.addr && !kdata.num) {
773 /* Query the size of the resource. */
774 rc = HYPERVISOR_memory_op(XENMEM_acquire_resource, &xdata);
775 if (rc)
776 return rc;
777 return __put_user(xdata.nr_frames, &udata->num);
778 }
779
780 down_write(&mm->mmap_sem);
781
782 vma = find_vma(mm, kdata.addr);
783 if (!vma || vma->vm_ops != &privcmd_vm_ops) {
784 rc = -EINVAL;
785 goto out;
786 }
787
788 pfns = kcalloc(kdata.num, sizeof(*pfns), GFP_KERNEL | __GFP_NOWARN);
789 if (!pfns) {
790 rc = -ENOMEM;
791 goto out;
792 }
793
794 if (xen_feature(XENFEAT_auto_translated_physmap)) {
795 unsigned int nr = DIV_ROUND_UP(kdata.num, XEN_PFN_PER_PAGE);
796 struct page **pages;
797 unsigned int i;
798
799 rc = alloc_empty_pages(vma, nr);
800 if (rc < 0)
801 goto out;
802
803 pages = vma->vm_private_data;
804 for (i = 0; i < kdata.num; i++) {
805 xen_pfn_t pfn =
806 page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
807
808 pfns[i] = pfn + (i % XEN_PFN_PER_PAGE);
809 }
810 } else
811 vma->vm_private_data = PRIV_VMA_LOCKED;
812
813 xdata.frame = kdata.idx;
814 xdata.nr_frames = kdata.num;
815 set_xen_guest_handle(xdata.frame_list, pfns);
816
817 xen_preemptible_hcall_begin();
818 rc = HYPERVISOR_memory_op(XENMEM_acquire_resource, &xdata);
819 xen_preemptible_hcall_end();
820
821 if (rc)
822 goto out;
823
824 if (xen_feature(XENFEAT_auto_translated_physmap)) {
825 struct remap_pfn r = {
826 .mm = vma->vm_mm,
827 .pages = vma->vm_private_data,
828 .prot = vma->vm_page_prot,
829 };
830
831 rc = apply_to_page_range(r.mm, kdata.addr,
832 kdata.num << PAGE_SHIFT,
833 remap_pfn_fn, &r);
834 } else {
835 unsigned int domid =
836 (xdata.flags & XENMEM_rsrc_acq_caller_owned) ?
837 DOMID_SELF : kdata.dom;
838 int num, *errs = (int *)pfns;
839
840 BUILD_BUG_ON(sizeof(*errs) > sizeof(*pfns));
841 num = xen_remap_domain_mfn_array(vma,
842 kdata.addr & PAGE_MASK,
843 pfns, kdata.num, errs,
844 vma->vm_page_prot,
845 domid,
846 vma->vm_private_data);
847 if (num < 0)
848 rc = num;
849 else if (num != kdata.num) {
850 unsigned int i;
851
852 for (i = 0; i < num; i++) {
853 rc = errs[i];
854 if (rc < 0)
855 break;
856 }
857 } else
858 rc = 0;
859 }
860
861 out:
862 up_write(&mm->mmap_sem);
863 kfree(pfns);
864
865 return rc;
866 }
867
privcmd_ioctl(struct file * file,unsigned int cmd,unsigned long data)868 static long privcmd_ioctl(struct file *file,
869 unsigned int cmd, unsigned long data)
870 {
871 int ret = -ENOTTY;
872 void __user *udata = (void __user *) data;
873
874 switch (cmd) {
875 case IOCTL_PRIVCMD_HYPERCALL:
876 ret = privcmd_ioctl_hypercall(file, udata);
877 break;
878
879 case IOCTL_PRIVCMD_MMAP:
880 ret = privcmd_ioctl_mmap(file, udata);
881 break;
882
883 case IOCTL_PRIVCMD_MMAPBATCH:
884 ret = privcmd_ioctl_mmap_batch(file, udata, 1);
885 break;
886
887 case IOCTL_PRIVCMD_MMAPBATCH_V2:
888 ret = privcmd_ioctl_mmap_batch(file, udata, 2);
889 break;
890
891 case IOCTL_PRIVCMD_DM_OP:
892 ret = privcmd_ioctl_dm_op(file, udata);
893 break;
894
895 case IOCTL_PRIVCMD_RESTRICT:
896 ret = privcmd_ioctl_restrict(file, udata);
897 break;
898
899 case IOCTL_PRIVCMD_MMAP_RESOURCE:
900 ret = privcmd_ioctl_mmap_resource(file, udata);
901 break;
902
903 default:
904 break;
905 }
906
907 return ret;
908 }
909
privcmd_open(struct inode * ino,struct file * file)910 static int privcmd_open(struct inode *ino, struct file *file)
911 {
912 struct privcmd_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
913
914 if (!data)
915 return -ENOMEM;
916
917 /* DOMID_INVALID implies no restriction */
918 data->domid = DOMID_INVALID;
919
920 file->private_data = data;
921 return 0;
922 }
923
privcmd_release(struct inode * ino,struct file * file)924 static int privcmd_release(struct inode *ino, struct file *file)
925 {
926 struct privcmd_data *data = file->private_data;
927
928 kfree(data);
929 return 0;
930 }
931
privcmd_close(struct vm_area_struct * vma)932 static void privcmd_close(struct vm_area_struct *vma)
933 {
934 struct page **pages = vma->vm_private_data;
935 int numpgs = vma_pages(vma);
936 int numgfns = (vma->vm_end - vma->vm_start) >> XEN_PAGE_SHIFT;
937 int rc;
938
939 if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)
940 return;
941
942 rc = xen_unmap_domain_gfn_range(vma, numgfns, pages);
943 if (rc == 0)
944 free_xenballooned_pages(numpgs, pages);
945 else
946 pr_crit("unable to unmap MFN range: leaking %d pages. rc=%d\n",
947 numpgs, rc);
948 kfree(pages);
949 }
950
privcmd_fault(struct vm_fault * vmf)951 static vm_fault_t privcmd_fault(struct vm_fault *vmf)
952 {
953 printk(KERN_DEBUG "privcmd_fault: vma=%p %lx-%lx, pgoff=%lx, uv=%p\n",
954 vmf->vma, vmf->vma->vm_start, vmf->vma->vm_end,
955 vmf->pgoff, (void *)vmf->address);
956
957 return VM_FAULT_SIGBUS;
958 }
959
960 static const struct vm_operations_struct privcmd_vm_ops = {
961 .close = privcmd_close,
962 .fault = privcmd_fault
963 };
964
privcmd_mmap(struct file * file,struct vm_area_struct * vma)965 static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)
966 {
967 /* DONTCOPY is essential for Xen because copy_page_range doesn't know
968 * how to recreate these mappings */
969 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTCOPY |
970 VM_DONTEXPAND | VM_DONTDUMP;
971 vma->vm_ops = &privcmd_vm_ops;
972 vma->vm_private_data = NULL;
973
974 return 0;
975 }
976
977 /*
978 * For MMAPBATCH*. This allows asserting the singleshot mapping
979 * on a per pfn/pte basis. Mapping calls that fail with ENOENT
980 * can be then retried until success.
981 */
is_mapped_fn(pte_t * pte,struct page * pmd_page,unsigned long addr,void * data)982 static int is_mapped_fn(pte_t *pte, struct page *pmd_page,
983 unsigned long addr, void *data)
984 {
985 return pte_none(*pte) ? 0 : -EBUSY;
986 }
987
privcmd_vma_range_is_mapped(struct vm_area_struct * vma,unsigned long addr,unsigned long nr_pages)988 static int privcmd_vma_range_is_mapped(
989 struct vm_area_struct *vma,
990 unsigned long addr,
991 unsigned long nr_pages)
992 {
993 return apply_to_page_range(vma->vm_mm, addr, nr_pages << PAGE_SHIFT,
994 is_mapped_fn, NULL) != 0;
995 }
996
997 const struct file_operations xen_privcmd_fops = {
998 .owner = THIS_MODULE,
999 .unlocked_ioctl = privcmd_ioctl,
1000 .open = privcmd_open,
1001 .release = privcmd_release,
1002 .mmap = privcmd_mmap,
1003 };
1004 EXPORT_SYMBOL_GPL(xen_privcmd_fops);
1005
1006 static struct miscdevice privcmd_dev = {
1007 .minor = MISC_DYNAMIC_MINOR,
1008 .name = "xen/privcmd",
1009 .fops = &xen_privcmd_fops,
1010 };
1011
privcmd_init(void)1012 static int __init privcmd_init(void)
1013 {
1014 int err;
1015
1016 if (!xen_domain())
1017 return -ENODEV;
1018
1019 err = misc_register(&privcmd_dev);
1020 if (err != 0) {
1021 pr_err("Could not register Xen privcmd device\n");
1022 return err;
1023 }
1024
1025 err = misc_register(&xen_privcmdbuf_dev);
1026 if (err != 0) {
1027 pr_err("Could not register Xen hypercall-buf device\n");
1028 misc_deregister(&privcmd_dev);
1029 return err;
1030 }
1031
1032 return 0;
1033 }
1034
privcmd_exit(void)1035 static void __exit privcmd_exit(void)
1036 {
1037 misc_deregister(&privcmd_dev);
1038 misc_deregister(&xen_privcmdbuf_dev);
1039 }
1040
1041 module_init(privcmd_init);
1042 module_exit(privcmd_exit);
1043