drivers/xen/privcmd.c

   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
  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
  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  */
 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  */
 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  */
 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
 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
 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  */
 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
 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
 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  */
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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  */
 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
 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
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
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);