drivers/xen/privcmd.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /******************************************************************************
   3  * privcmd.c
   4  *
   5  * Interface to privileged domain-0 commands.
   6  *
   7  * Copyright (c) 2002-2004, K A Fraser, B Dragovic
   8  */
   9
  10 #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/sched.h>
  15 #include <linux/slab.h>
  16 #include <linux/string.h>
  17 #include <linux/errno.h>
  18 #include <linux/mm.h>
  19 #include <linux/mman.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/swap.h>
  22 #include <linux/highmem.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/seq_file.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/moduleparam.h>
  27
  28 #include <asm/pgalloc.h>
  29 #include <asm/pgtable.h>
  30 #include <asm/tlb.h>
  31 #include <asm/xen/hypervisor.h>
  32 #include <asm/xen/hypercall.h>
  33
  34 #include <xen/xen.h>
  35 #include <xen/privcmd.h>
  36 #include <xen/interface/xen.h>
  37 #include <xen/interface/memory.h>
  38 #include <xen/interface/hvm/dm_op.h>
  39 #include <xen/features.h>
  40 #include <xen/page.h>
  41 #include <xen/xen-ops.h>
  42 #include <xen/balloon.h>
  43
  44 #include "privcmd.h"
  45
  46 MODULE_LICENSE("GPL");
  47
  48 #define PRIV_VMA_LOCKED ((void *)1)
  49
  50 static unsigned int privcmd_dm_op_max_num = 16;
  51 module_param_named(dm_op_max_nr_bufs, privcmd_dm_op_max_num, uint, 0644);
  52 MODULE_PARM_DESC(dm_op_max_nr_bufs,
  53                  "Maximum number of buffers per dm_op hypercall");
  54
  55 static unsigned int privcmd_dm_op_buf_max_size = 4096;
  56 module_param_named(dm_op_buf_max_size, privcmd_dm_op_buf_max_size, uint,
  57                    0644);
  58 MODULE_PARM_DESC(dm_op_buf_max_size,
  59                  "Maximum size of a dm_op hypercall buffer");
  60
  61 struct privcmd_data {
  62         domid_t domid;
  63 };
  64
  65 static int privcmd_vma_range_is_mapped(
  66                struct vm_area_struct *vma,
  67                unsigned long addr,
  68                unsigned long nr_pages);
  69
  70 static long privcmd_ioctl_hypercall(struct file *file, void __user *udata)
  71 {
  72         struct privcmd_data *data = file->private_data;
  73         struct privcmd_hypercall hypercall;
  74         long ret;
  75
  76         /* Disallow arbitrary hypercalls if restricted */
  77         if (data->domid != DOMID_INVALID)
  78                 return -EPERM;
  79
  80         if (copy_from_user(&hypercall, udata, sizeof(hypercall)))
  81                 return -EFAULT;
  82
  83         xen_preemptible_hcall_begin();
  84         ret = privcmd_call(hypercall.op,
  85                            hypercall.arg[0], hypercall.arg[1],
  86                            hypercall.arg[2], hypercall.arg[3],
  87                            hypercall.arg[4]);
  88         xen_preemptible_hcall_end();
  89
  90         return ret;
  91 }
  92
  93 static void free_page_list(struct list_head *pages)
  94 {
  95         struct page *p, *n;
  96
  97         list_for_each_entry_safe(p, n, pages, lru)
  98                 __free_page(p);
  99
 100         INIT_LIST_HEAD(pages);
 101 }
 102
 103 /*
 104  * Given an array of items in userspace, return a list of pages
 105  * containing the data.  If copying fails, either because of memory
 106  * allocation failure or a problem reading user memory, return an
 107  * error code; its up to the caller to dispose of any partial list.
 108  */
 109 static int gather_array(struct list_head *pagelist,
 110                         unsigned nelem, size_t size,
 111                         const void __user *data)
 112 {
 113         unsigned pageidx;
 114         void *pagedata;
 115         int ret;
 116
 117         if (size > PAGE_SIZE)
 118                 return 0;
 119
 120         pageidx = PAGE_SIZE;
 121         pagedata = NULL;        /* quiet, gcc */
 122         while (nelem--) {
 123                 if (pageidx > PAGE_SIZE-size) {
 124                         struct page *page = alloc_page(GFP_KERNEL);
 125
 126                         ret = -ENOMEM;
 127                         if (page == NULL)
 128                                 goto fail;
 129
 130                         pagedata = page_address(page);
 131
 132                         list_add_tail(&page->lru, pagelist);
 133                         pageidx = 0;
 134                 }
 135
 136                 ret = -EFAULT;
 137                 if (copy_from_user(pagedata + pageidx, data, size))
 138                         goto fail;
 139
 140                 data += size;
 141                 pageidx += size;
 142         }
 143
 144         ret = 0;
 145
 146 fail:
 147         return ret;
 148 }
 149
 150 /*
 151  * Call function "fn" on each element of the array fragmented
 152  * over a list of pages.
 153  */
 154 static int traverse_pages(unsigned nelem, size_t size,
 155                           struct list_head *pos,
 156                           int (*fn)(void *data, void *state),
 157                           void *state)
 158 {
 159         void *pagedata;
 160         unsigned pageidx;
 161         int ret = 0;
 162
 163         BUG_ON(size > PAGE_SIZE);
 164
 165         pageidx = PAGE_SIZE;
 166         pagedata = NULL;        /* hush, gcc */
 167
 168         while (nelem--) {
 169                 if (pageidx > PAGE_SIZE-size) {
 170                         struct page *page;
 171                         pos = pos->next;
 172                         page = list_entry(pos, struct page, lru);
 173                         pagedata = page_address(page);
 174                         pageidx = 0;
 175                 }
 176
 177                 ret = (*fn)(pagedata + pageidx, state);
 178                 if (ret)
 179                         break;
 180                 pageidx += size;
 181         }
 182
 183         return ret;
 184 }
 185
 186 /*
 187  * Similar to traverse_pages, but use each page as a "block" of
 188  * data to be processed as one unit.
 189  */
 190 static int traverse_pages_block(unsigned nelem, size_t size,
 191                                 struct list_head *pos,
 192                                 int (*fn)(void *data, int nr, void *state),
 193                                 void *state)
 194 {
 195         void *pagedata;
 196         int ret = 0;
 197
 198         BUG_ON(size > PAGE_SIZE);
 199
 200         while (nelem) {
 201                 int nr = (PAGE_SIZE/size);
 202                 struct page *page;
 203                 if (nr > nelem)
 204                         nr = nelem;
 205                 pos = pos->next;
 206                 page = list_entry(pos, struct page, lru);
 207                 pagedata = page_address(page);
 208                 ret = (*fn)(pagedata, nr, state);
 209                 if (ret)
 210                         break;
 211                 nelem -= nr;
 212         }
 213
 214         return ret;
 215 }
 216
 217 struct mmap_gfn_state {
 218         unsigned long va;
 219         struct vm_area_struct *vma;
 220         domid_t domain;
 221 };
 222
 223 static int mmap_gfn_range(void *data, void *state)
 224 {
 225         struct privcmd_mmap_entry *msg = data;
 226         struct mmap_gfn_state *st = state;
 227         struct vm_area_struct *vma = st->vma;
 228         int rc;
 229
 230         /* Do not allow range to wrap the address space. */
 231         if ((msg->npages > (LONG_MAX >> PAGE_SHIFT)) ||
 232             ((unsigned long)(msg->npages << PAGE_SHIFT) >= -st->va))
 233                 return -EINVAL;
 234
 235         /* Range chunks must be contiguous in va space. */
 236         if ((msg->va != st->va) ||
 237             ((msg->va+(msg->npages<<PAGE_SHIFT)) > vma->vm_end))
 238                 return -EINVAL;
 239
 240         rc = xen_remap_domain_gfn_range(vma,
 241                                         msg->va & PAGE_MASK,
 242                                         msg->mfn, msg->npages,
 243                                         vma->vm_page_prot,
 244                                         st->domain, NULL);
 245         if (rc < 0)
 246                 return rc;
 247
 248         st->va += msg->npages << PAGE_SHIFT;
 249
 250         return 0;
 251 }
 252
 253 static long privcmd_ioctl_mmap(struct file *file, void __user *udata)
 254 {
 255         struct privcmd_data *data = file->private_data;
 256         struct privcmd_mmap mmapcmd;
 257         struct mm_struct *mm = current->mm;
 258         struct vm_area_struct *vma;
 259         int rc;
 260         LIST_HEAD(pagelist);
 261         struct mmap_gfn_state state;
 262
 263         /* We only support privcmd_ioctl_mmap_batch for auto translated. */
 264         if (xen_feature(XENFEAT_auto_translated_physmap))
 265                 return -ENOSYS;
 266
 267         if (copy_from_user(&mmapcmd, udata, sizeof(mmapcmd)))
 268                 return -EFAULT;
 269
 270         /* If restriction is in place, check the domid matches */
 271         if (data->domid != DOMID_INVALID && data->domid != mmapcmd.dom)
 272                 return -EPERM;
 273
 274         rc = gather_array(&pagelist,
 275                           mmapcmd.num, sizeof(struct privcmd_mmap_entry),
 276                           mmapcmd.entry);
 277
 278         if (rc || list_empty(&pagelist))
 279                 goto out;
 280
 281         down_write(&mm->mmap_sem);
 282
 283         {
 284                 struct page *page = list_first_entry(&pagelist,
 285                                                      struct page, lru);
 286                 struct privcmd_mmap_entry *msg = page_address(page);
 287
 288                 vma = find_vma(mm, msg->va);
 289                 rc = -EINVAL;
 290
 291                 if (!vma || (msg->va != vma->vm_start) || vma->vm_private_data)
 292                         goto out_up;
 293                 vma->vm_private_data = PRIV_VMA_LOCKED;
 294         }
 295
 296         state.va = vma->vm_start;
 297         state.vma = vma;
 298         state.domain = mmapcmd.dom;
 299
 300         rc = traverse_pages(mmapcmd.num, sizeof(struct privcmd_mmap_entry),
 301                             &pagelist,
 302                             mmap_gfn_range, &state);
 303
 304
 305 out_up:
 306         up_write(&mm->mmap_sem);
 307
 308 out:
 309         free_page_list(&pagelist);
 310
 311         return rc;
 312 }
 313
 314 struct mmap_batch_state {
 315         domid_t domain;
 316         unsigned long va;
 317         struct vm_area_struct *vma;
 318         int index;
 319         /* A tristate:
 320          *      0 for no errors
 321          *      1 if at least one error has happened (and no
 322          *          -ENOENT errors have happened)
 323          *      -ENOENT if at least 1 -ENOENT has happened.
 324          */
 325         int global_error;
 326         int version;
 327
 328         /* User-space gfn array to store errors in the second pass for V1. */
 329         xen_pfn_t __user *user_gfn;
 330         /* User-space int array to store errors in the second pass for V2. */
 331         int __user *user_err;
 332 };
 333
 334 /* auto translated dom0 note: if domU being created is PV, then gfn is
 335  * mfn(addr on bus). If it's auto xlated, then gfn is pfn (input to HAP).
 336  */
 337 static int mmap_batch_fn(void *data, int nr, void *state)
 338 {
 339         xen_pfn_t *gfnp = data;
 340         struct mmap_batch_state *st = state;
 341         struct vm_area_struct *vma = st->vma;
 342         struct page **pages = vma->vm_private_data;
 343         struct page **cur_pages = NULL;
 344         int ret;
 345
 346         if (xen_feature(XENFEAT_auto_translated_physmap))
 347                 cur_pages = &pages[st->index];
 348
 349         BUG_ON(nr < 0);
 350         ret = xen_remap_domain_gfn_array(st->vma, st->va & PAGE_MASK, gfnp, nr,
 351                                          (int *)gfnp, st->vma->vm_page_prot,
 352                                          st->domain, cur_pages);
 353
 354         /* Adjust the global_error? */
 355         if (ret != nr) {
 356                 if (ret == -ENOENT)
 357                         st->global_error = -ENOENT;
 358                 else {
 359                         /* Record that at least one error has happened. */
 360                         if (st->global_error == 0)
 361                                 st->global_error = 1;
 362                 }
 363         }
 364         st->va += XEN_PAGE_SIZE * nr;
 365         st->index += nr / XEN_PFN_PER_PAGE;
 366
 367         return 0;
 368 }
 369
 370 static int mmap_return_error(int err, struct mmap_batch_state *st)
 371 {
 372         int ret;
 373
 374         if (st->version == 1) {
 375                 if (err) {
 376                         xen_pfn_t gfn;
 377
 378                         ret = get_user(gfn, st->user_gfn);
 379                         if (ret < 0)
 380                                 return ret;
 381                         /*
 382                          * V1 encodes the error codes in the 32bit top
 383                          * nibble of the gfn (with its known
 384                          * limitations vis-a-vis 64 bit callers).
 385                          */
 386                         gfn |= (err == -ENOENT) ?
 387                                 PRIVCMD_MMAPBATCH_PAGED_ERROR :
 388                                 PRIVCMD_MMAPBATCH_MFN_ERROR;
 389                         return __put_user(gfn, st->user_gfn++);
 390                 } else
 391                         st->user_gfn++;
 392         } else { /* st->version == 2 */
 393                 if (err)
 394                         return __put_user(err, st->user_err++);
 395                 else
 396                         st->user_err++;
 397         }
 398
 399         return 0;
 400 }
 401
 402 static int mmap_return_errors(void *data, int nr, void *state)
 403 {
 404         struct mmap_batch_state *st = state;
 405         int *errs = data;
 406         int i;
 407         int ret;
 408
 409         for (i = 0; i < nr; i++) {
 410                 ret = mmap_return_error(errs[i], st);
 411                 if (ret < 0)
 412                         return ret;
 413         }
 414         return 0;
 415 }
 416
 417 /* Allocate pfns that are then mapped with gfns from foreign domid. Update
 418  * the vma with the page info to use later.
 419  * Returns: 0 if success, otherwise -errno
 420  */
 421 static int alloc_empty_pages(struct vm_area_struct *vma, int numpgs)
 422 {
 423         int rc;
 424         struct page **pages;
 425
 426         pages = kcalloc(numpgs, sizeof(pages[0]), GFP_KERNEL);
 427         if (pages == NULL)
 428                 return -ENOMEM;
 429
 430         rc = alloc_xenballooned_pages(numpgs, pages);
 431         if (rc != 0) {
 432                 pr_warn("%s Could not alloc %d pfns rc:%d\n", __func__,
 433                         numpgs, rc);
 434                 kfree(pages);
 435                 return -ENOMEM;
 436         }
 437         BUG_ON(vma->vm_private_data != NULL);
 438         vma->vm_private_data = pages;
 439
 440         return 0;
 441 }
 442
 443 static const struct vm_operations_struct privcmd_vm_ops;
 444
 445 static long privcmd_ioctl_mmap_batch(
 446         struct file *file, void __user *udata, int version)
 447 {
 448         struct privcmd_data *data = file->private_data;
 449         int ret;
 450         struct privcmd_mmapbatch_v2 m;
 451         struct mm_struct *mm = current->mm;
 452         struct vm_area_struct *vma;
 453         unsigned long nr_pages;
 454         LIST_HEAD(pagelist);
 455         struct mmap_batch_state state;
 456
 457         switch (version) {
 458         case 1:
 459                 if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch)))
 460                         return -EFAULT;
 461                 /* Returns per-frame error in m.arr. */
 462                 m.err = NULL;
 463                 if (!access_ok(m.arr, m.num * sizeof(*m.arr)))
 464                         return -EFAULT;
 465                 break;
 466         case 2:
 467                 if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch_v2)))
 468                         return -EFAULT;
 469                 /* Returns per-frame error code in m.err. */
 470                 if (!access_ok(m.err, m.num * (sizeof(*m.err))))
 471                         return -EFAULT;
 472                 break;
 473         default:
 474                 return -EINVAL;
 475         }
 476
 477         /* If restriction is in place, check the domid matches */
 478         if (data->domid != DOMID_INVALID && data->domid != m.dom)
 479                 return -EPERM;
 480
 481         nr_pages = DIV_ROUND_UP(m.num, XEN_PFN_PER_PAGE);
 482         if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
 483                 return -EINVAL;
 484
 485         ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t), m.arr);
 486
 487         if (ret)
 488                 goto out;
 489         if (list_empty(&pagelist)) {
 490                 ret = -EINVAL;
 491                 goto out;
 492         }
 493
 494         if (version == 2) {
 495                 /* Zero error array now to only copy back actual errors. */
 496                 if (clear_user(m.err, sizeof(int) * m.num)) {
 497                         ret = -EFAULT;
 498                         goto out;
 499                 }
 500         }
 501
 502         down_write(&mm->mmap_sem);
 503
 504         vma = find_vma(mm, m.addr);
 505         if (!vma ||
 506             vma->vm_ops != &privcmd_vm_ops) {
 507                 ret = -EINVAL;
 508                 goto out_unlock;
 509         }
 510
 511         /*
 512          * Caller must either:
 513          *
 514          * Map the whole VMA range, which will also allocate all the
 515          * pages required for the auto_translated_physmap case.
 516          *
 517          * Or
 518          *
 519          * Map unmapped holes left from a previous map attempt (e.g.,
 520          * because those foreign frames were previously paged out).
 521          */
 522         if (vma->vm_private_data == NULL) {
 523                 if (m.addr != vma->vm_start ||
 524                     m.addr + (nr_pages << PAGE_SHIFT) != vma->vm_end) {
 525                         ret = -EINVAL;
 526                         goto out_unlock;
 527                 }
 528                 if (xen_feature(XENFEAT_auto_translated_physmap)) {
 529                         ret = alloc_empty_pages(vma, nr_pages);
 530                         if (ret < 0)
 531                                 goto out_unlock;
 532                 } else
 533                         vma->vm_private_data = PRIV_VMA_LOCKED;
 534         } else {
 535                 if (m.addr < vma->vm_start ||
 536                     m.addr + (nr_pages << PAGE_SHIFT) > vma->vm_end) {
 537                         ret = -EINVAL;
 538                         goto out_unlock;
 539                 }
 540                 if (privcmd_vma_range_is_mapped(vma, m.addr, nr_pages)) {
 541                         ret = -EINVAL;
 542                         goto out_unlock;
 543                 }
 544         }
 545
 546         state.domain        = m.dom;
 547         state.vma           = vma;
 548         state.va            = m.addr;
 549         state.index         = 0;
 550         state.global_error  = 0;
 551         state.version       = version;
 552
 553         BUILD_BUG_ON(((PAGE_SIZE / sizeof(xen_pfn_t)) % XEN_PFN_PER_PAGE) != 0);
 554         /* mmap_batch_fn guarantees ret == 0 */
 555         BUG_ON(traverse_pages_block(m.num, sizeof(xen_pfn_t),
 556                                     &pagelist, mmap_batch_fn, &state));
 557
 558         up_write(&mm->mmap_sem);
 559
 560         if (state.global_error) {
 561                 /* Write back errors in second pass. */
 562                 state.user_gfn = (xen_pfn_t *)m.arr;
 563                 state.user_err = m.err;
 564                 ret = traverse_pages_block(m.num, sizeof(xen_pfn_t),
 565                                            &pagelist, mmap_return_errors, &state);
 566         } else
 567                 ret = 0;
 568
 569         /* If we have not had any EFAULT-like global errors then set the global
 570          * error to -ENOENT if necessary. */
 571         if ((ret == 0) && (state.global_error == -ENOENT))
 572                 ret = -ENOENT;
 573
 574 out:
 575         free_page_list(&pagelist);
 576         return ret;
 577
 578 out_unlock:
 579         up_write(&mm->mmap_sem);
 580         goto out;
 581 }
 582
 583 static int lock_pages(
 584         struct privcmd_dm_op_buf kbufs[], unsigned int num,
 585         struct page *pages[], unsigned int nr_pages)
 586 {
 587         unsigned int i;
 588
 589         for (i = 0; i < num; i++) {
 590                 unsigned int requested;
 591                 int pinned;
 592
 593                 requested = DIV_ROUND_UP(
 594                         offset_in_page(kbufs[i].uptr) + kbufs[i].size,
 595                         PAGE_SIZE);
 596                 if (requested > nr_pages)
 597                         return -ENOSPC;
 598
 599                 pinned = get_user_pages_fast(
 600                         (unsigned long) kbufs[i].uptr,
 601                         requested, FOLL_WRITE, pages);
 602                 if (pinned < 0)
 603                         return pinned;
 604
 605                 nr_pages -= pinned;
 606                 pages += pinned;
 607         }
 608
 609         return 0;
 610 }
 611
 612 static void unlock_pages(struct page *pages[], unsigned int nr_pages)
 613 {
 614         unsigned int i;
 615
 616         if (!pages)
 617                 return;
 618
 619         for (i = 0; i < nr_pages; i++) {
 620                 if (pages[i])
 621                         put_page(pages[i]);
 622         }
 623 }
 624
 625 static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
 626 {
 627         struct privcmd_data *data = file->private_data;
 628         struct privcmd_dm_op kdata;
 629         struct privcmd_dm_op_buf *kbufs;
 630         unsigned int nr_pages = 0;
 631         struct page **pages = NULL;
 632         struct xen_dm_op_buf *xbufs = NULL;
 633         unsigned int i;
 634         long rc;
 635
 636         if (copy_from_user(&kdata, udata, sizeof(kdata)))
 637                 return -EFAULT;
 638
 639         /* If restriction is in place, check the domid matches */
 640         if (data->domid != DOMID_INVALID && data->domid != kdata.dom)
 641                 return -EPERM;
 642
 643         if (kdata.num == 0)
 644                 return 0;
 645
 646         if (kdata.num > privcmd_dm_op_max_num)
 647                 return -E2BIG;
 648
 649         kbufs = kcalloc(kdata.num, sizeof(*kbufs), GFP_KERNEL);
 650         if (!kbufs)
 651                 return -ENOMEM;
 652
 653         if (copy_from_user(kbufs, kdata.ubufs,
 654                            sizeof(*kbufs) * kdata.num)) {
 655                 rc = -EFAULT;
 656                 goto out;
 657         }
 658
 659         for (i = 0; i < kdata.num; i++) {
 660                 if (kbufs[i].size > privcmd_dm_op_buf_max_size) {
 661                         rc = -E2BIG;
 662                         goto out;
 663                 }
 664
 665                 if (!access_ok(kbufs[i].uptr,
 666                                kbufs[i].size)) {
 667                         rc = -EFAULT;
 668                         goto out;
 669                 }
 670
 671                 nr_pages += DIV_ROUND_UP(
 672                         offset_in_page(kbufs[i].uptr) + kbufs[i].size,
 673                         PAGE_SIZE);
 674         }
 675
 676         pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL);
 677         if (!pages) {
 678                 rc = -ENOMEM;
 679                 goto out;
 680         }
 681
 682         xbufs = kcalloc(kdata.num, sizeof(*xbufs), GFP_KERNEL);
 683         if (!xbufs) {
 684                 rc = -ENOMEM;
 685                 goto out;
 686         }
 687
 688         rc = lock_pages(kbufs, kdata.num, pages, nr_pages);
 689         if (rc)
 690                 goto out;
 691
 692         for (i = 0; i < kdata.num; i++) {
 693                 set_xen_guest_handle(xbufs[i].h, kbufs[i].uptr);
 694                 xbufs[i].size = kbufs[i].size;
 695         }
 696
 697         xen_preemptible_hcall_begin();
 698         rc = HYPERVISOR_dm_op(kdata.dom, kdata.num, xbufs);
 699         xen_preemptible_hcall_end();
 700
 701 out:
 702         unlock_pages(pages, nr_pages);
 703         kfree(xbufs);
 704         kfree(pages);
 705         kfree(kbufs);
 706
 707         return rc;
 708 }
 709
 710 static long privcmd_ioctl_restrict(struct file *file, void __user *udata)
 711 {
 712         struct privcmd_data *data = file->private_data;
 713         domid_t dom;
 714
 715         if (copy_from_user(&dom, udata, sizeof(dom)))
 716                 return -EFAULT;
 717
 718         /* Set restriction to the specified domain, or check it matches */
 719         if (data->domid == DOMID_INVALID)
 720                 data->domid = dom;
 721         else if (data->domid != dom)
 722                 return -EINVAL;
 723
 724         return 0;
 725 }
 726
 727 static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
 728 {
 729         struct privcmd_data *data = file->private_data;
 730         struct mm_struct *mm = current->mm;
 731         struct vm_area_struct *vma;
 732         struct privcmd_mmap_resource kdata;
 733         xen_pfn_t *pfns = NULL;
 734         struct xen_mem_acquire_resource xdata;
 735         int rc;
 736
 737         if (copy_from_user(&kdata, udata, sizeof(kdata)))
 738                 return -EFAULT;
 739
 740         /* If restriction is in place, check the domid matches */
 741         if (data->domid != DOMID_INVALID && data->domid != kdata.dom)
 742                 return -EPERM;
 743
 744         down_write(&mm->mmap_sem);
 745
 746         vma = find_vma(mm, kdata.addr);
 747         if (!vma || vma->vm_ops != &privcmd_vm_ops) {
 748                 rc = -EINVAL;
 749                 goto out;
 750         }
 751
 752         pfns = kcalloc(kdata.num, sizeof(*pfns), GFP_KERNEL);
 753         if (!pfns) {
 754                 rc = -ENOMEM;
 755                 goto out;
 756         }
 757
 758         if (IS_ENABLED(CONFIG_XEN_AUTO_XLATE) &&
 759             xen_feature(XENFEAT_auto_translated_physmap)) {
 760                 unsigned int nr = DIV_ROUND_UP(kdata.num, XEN_PFN_PER_PAGE);
 761                 struct page **pages;
 762                 unsigned int i;
 763
 764                 rc = alloc_empty_pages(vma, nr);
 765                 if (rc < 0)
 766                         goto out;
 767
 768                 pages = vma->vm_private_data;
 769                 for (i = 0; i < kdata.num; i++) {
 770                         xen_pfn_t pfn =
 771                                 page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
 772
 773                         pfns[i] = pfn + (i % XEN_PFN_PER_PAGE);
 774                 }
 775         } else
 776                 vma->vm_private_data = PRIV_VMA_LOCKED;
 777
 778         memset(&xdata, 0, sizeof(xdata));
 779         xdata.domid = kdata.dom;
 780         xdata.type = kdata.type;
 781         xdata.id = kdata.id;
 782         xdata.frame = kdata.idx;
 783         xdata.nr_frames = kdata.num;
 784         set_xen_guest_handle(xdata.frame_list, pfns);
 785
 786         xen_preemptible_hcall_begin();
 787         rc = HYPERVISOR_memory_op(XENMEM_acquire_resource, &xdata);
 788         xen_preemptible_hcall_end();
 789
 790         if (rc)
 791                 goto out;
 792
 793         if (IS_ENABLED(CONFIG_XEN_AUTO_XLATE) &&
 794             xen_feature(XENFEAT_auto_translated_physmap)) {
 795                 rc = xen_remap_vma_range(vma, kdata.addr, kdata.num << PAGE_SHIFT);
 796         } else {
 797                 unsigned int domid =
 798                         (xdata.flags & XENMEM_rsrc_acq_caller_owned) ?
 799                         DOMID_SELF : kdata.dom;
 800                 int num;
 801
 802                 num = xen_remap_domain_mfn_array(vma,
 803                                                  kdata.addr & PAGE_MASK,
 804                                                  pfns, kdata.num, (int *)pfns,
 805                                                  vma->vm_page_prot,
 806                                                  domid,
 807                                                  vma->vm_private_data);
 808                 if (num < 0)
 809                         rc = num;
 810                 else if (num != kdata.num) {
 811                         unsigned int i;
 812
 813                         for (i = 0; i < num; i++) {
 814                                 rc = pfns[i];
 815                                 if (rc < 0)
 816                                         break;
 817                         }
 818                 } else
 819                         rc = 0;
 820         }
 821
 822 out:
 823         up_write(&mm->mmap_sem);
 824         kfree(pfns);
 825
 826         return rc;
 827 }
 828
 829 static long privcmd_ioctl(struct file *file,
 830                           unsigned int cmd, unsigned long data)
 831 {
 832         int ret = -ENOTTY;
 833         void __user *udata = (void __user *) data;
 834
 835         switch (cmd) {
 836         case IOCTL_PRIVCMD_HYPERCALL:
 837                 ret = privcmd_ioctl_hypercall(file, udata);
 838                 break;
 839
 840         case IOCTL_PRIVCMD_MMAP:
 841                 ret = privcmd_ioctl_mmap(file, udata);
 842                 break;
 843
 844         case IOCTL_PRIVCMD_MMAPBATCH:
 845                 ret = privcmd_ioctl_mmap_batch(file, udata, 1);
 846                 break;
 847
 848         case IOCTL_PRIVCMD_MMAPBATCH_V2:
 849                 ret = privcmd_ioctl_mmap_batch(file, udata, 2);
 850                 break;
 851
 852         case IOCTL_PRIVCMD_DM_OP:
 853                 ret = privcmd_ioctl_dm_op(file, udata);
 854                 break;
 855
 856         case IOCTL_PRIVCMD_RESTRICT:
 857                 ret = privcmd_ioctl_restrict(file, udata);
 858                 break;
 859
 860         case IOCTL_PRIVCMD_MMAP_RESOURCE:
 861                 ret = privcmd_ioctl_mmap_resource(file, udata);
 862                 break;
 863
 864         default:
 865                 break;
 866         }
 867
 868         return ret;
 869 }
 870
 871 static int privcmd_open(struct inode *ino, struct file *file)
 872 {
 873         struct privcmd_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
 874
 875         if (!data)
 876                 return -ENOMEM;
 877
 878         /* DOMID_INVALID implies no restriction */
 879         data->domid = DOMID_INVALID;
 880
 881         file->private_data = data;
 882         return 0;
 883 }
 884
 885 static int privcmd_release(struct inode *ino, struct file *file)
 886 {
 887         struct privcmd_data *data = file->private_data;
 888
 889         kfree(data);
 890         return 0;
 891 }
 892
 893 static void privcmd_close(struct vm_area_struct *vma)
 894 {
 895         struct page **pages = vma->vm_private_data;
 896         int numpgs = vma_pages(vma);
 897         int numgfns = (vma->vm_end - vma->vm_start) >> XEN_PAGE_SHIFT;
 898         int rc;
 899
 900         if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)
 901                 return;
 902
 903         rc = xen_unmap_domain_gfn_range(vma, numgfns, pages);
 904         if (rc == 0)
 905                 free_xenballooned_pages(numpgs, pages);
 906         else
 907                 pr_crit("unable to unmap MFN range: leaking %d pages. rc=%d\n",
 908                         numpgs, rc);
 909         kfree(pages);
 910 }
 911
 912 static vm_fault_t privcmd_fault(struct vm_fault *vmf)
 913 {
 914         printk(KERN_DEBUG "privcmd_fault: vma=%p %lx-%lx, pgoff=%lx, uv=%p\n",
 915                vmf->vma, vmf->vma->vm_start, vmf->vma->vm_end,
 916                vmf->pgoff, (void *)vmf->address);
 917
 918         return VM_FAULT_SIGBUS;
 919 }
 920
 921 static const struct vm_operations_struct privcmd_vm_ops = {
 922         .close = privcmd_close,
 923         .fault = privcmd_fault
 924 };
 925
 926 static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)
 927 {
 928         /* DONTCOPY is essential for Xen because copy_page_range doesn't know
 929          * how to recreate these mappings */
 930         vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTCOPY |
 931                          VM_DONTEXPAND | VM_DONTDUMP;
 932         vma->vm_ops = &privcmd_vm_ops;
 933         vma->vm_private_data = NULL;
 934
 935         return 0;
 936 }
 937
 938 /*
 939  * For MMAPBATCH*. This allows asserting the singleshot mapping
 940  * on a per pfn/pte basis. Mapping calls that fail with ENOENT
 941  * can be then retried until success.
 942  */
 943 static int is_mapped_fn(pte_t *pte, unsigned long addr, void *data)
 944 {
 945         return pte_none(*pte) ? 0 : -EBUSY;
 946 }
 947
 948 static int privcmd_vma_range_is_mapped(
 949                    struct vm_area_struct *vma,
 950                    unsigned long addr,
 951                    unsigned long nr_pages)
 952 {
 953         return apply_to_page_range(vma->vm_mm, addr, nr_pages << PAGE_SHIFT,
 954                                    is_mapped_fn, NULL) != 0;
 955 }
 956
 957 const struct file_operations xen_privcmd_fops = {
 958         .owner = THIS_MODULE,
 959         .unlocked_ioctl = privcmd_ioctl,
 960         .open = privcmd_open,
 961         .release = privcmd_release,
 962         .mmap = privcmd_mmap,
 963 };
 964 EXPORT_SYMBOL_GPL(xen_privcmd_fops);
 965
 966 static struct miscdevice privcmd_dev = {
 967         .minor = MISC_DYNAMIC_MINOR,
 968         .name = "xen/privcmd",
 969         .fops = &xen_privcmd_fops,
 970 };
 971
 972 static int __init privcmd_init(void)
 973 {
 974         int err;
 975
 976         if (!xen_domain())
 977                 return -ENODEV;
 978
 979         err = misc_register(&privcmd_dev);
 980         if (err != 0) {
 981                 pr_err("Could not register Xen privcmd device\n");
 982                 return err;
 983         }
 984
 985         err = misc_register(&xen_privcmdbuf_dev);
 986         if (err != 0) {
 987                 pr_err("Could not register Xen hypercall-buf device\n");
 988                 misc_deregister(&privcmd_dev);
 989                 return err;
 990         }
 991
 992         return 0;
 993 }
 994
 995 static void __exit privcmd_exit(void)
 996 {
 997         misc_deregister(&privcmd_dev);
 998         misc_deregister(&xen_privcmdbuf_dev);
 999 }
1000
1001 module_init(privcmd_init);
1002 module_exit(privcmd_exit);