arch/powerpc/kvm/book3s_64_vio.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
   5  * Copyright 2011 David Gibson, IBM Corporation <dwg@au1.ibm.com>
   6  * Copyright 2016 Alexey Kardashevskiy, IBM Corporation <aik@au1.ibm.com>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/string.h>
  11 #include <linux/kvm.h>
  12 #include <linux/kvm_host.h>
  13 #include <linux/highmem.h>
  14 #include <linux/gfp.h>
  15 #include <linux/slab.h>
  16 #include <linux/sched/signal.h>
  17 #include <linux/hugetlb.h>
  18 #include <linux/list.h>
  19 #include <linux/anon_inodes.h>
  20 #include <linux/iommu.h>
  21 #include <linux/file.h>
  22 #include <linux/mm.h>
  23
  24 #include <asm/kvm_ppc.h>
  25 #include <asm/kvm_book3s.h>
  26 #include <asm/book3s/64/mmu-hash.h>
  27 #include <asm/hvcall.h>
  28 #include <asm/synch.h>
  29 #include <asm/ppc-opcode.h>
  30 #include <asm/udbg.h>
  31 #include <asm/iommu.h>
  32 #include <asm/tce.h>
  33 #include <asm/mmu_context.h>
  34
  35 static struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm *kvm,
  36         unsigned long liobn)
  37 {
  38         struct kvmppc_spapr_tce_table *stt;
  39
  40         list_for_each_entry_lockless(stt, &kvm->arch.spapr_tce_tables, list)
  41                 if (stt->liobn == liobn)
  42                         return stt;
  43
  44         return NULL;
  45 }
  46
  47 static unsigned long kvmppc_tce_pages(unsigned long iommu_pages)
  48 {
  49         return ALIGN(iommu_pages * sizeof(u64), PAGE_SIZE) / PAGE_SIZE;
  50 }
  51
  52 static unsigned long kvmppc_stt_pages(unsigned long tce_pages)
  53 {
  54         unsigned long stt_bytes = sizeof(struct kvmppc_spapr_tce_table) +
  55                         (tce_pages * sizeof(struct page *));
  56
  57         return tce_pages + ALIGN(stt_bytes, PAGE_SIZE) / PAGE_SIZE;
  58 }
  59
  60 static void kvm_spapr_tce_iommu_table_free(struct rcu_head *head)
  61 {
  62         struct kvmppc_spapr_tce_iommu_table *stit = container_of(head,
  63                         struct kvmppc_spapr_tce_iommu_table, rcu);
  64
  65         iommu_tce_table_put(stit->tbl);
  66
  67         kfree(stit);
  68 }
  69
  70 static void kvm_spapr_tce_liobn_put(struct kref *kref)
  71 {
  72         struct kvmppc_spapr_tce_iommu_table *stit = container_of(kref,
  73                         struct kvmppc_spapr_tce_iommu_table, kref);
  74
  75         list_del_rcu(&stit->next);
  76
  77         call_rcu(&stit->rcu, kvm_spapr_tce_iommu_table_free);
  78 }
  79
  80 void kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
  81                                        struct iommu_group *grp)
  82 {
  83         int i;
  84         struct kvmppc_spapr_tce_table *stt;
  85         struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
  86         struct iommu_table_group *table_group = NULL;
  87
  88         rcu_read_lock();
  89         list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
  90
  91                 table_group = iommu_group_get_iommudata(grp);
  92                 if (WARN_ON(!table_group))
  93                         continue;
  94
  95                 list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
  96                         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
  97                                 if (table_group->tables[i] != stit->tbl)
  98                                         continue;
  99
 100                                 kref_put(&stit->kref, kvm_spapr_tce_liobn_put);
 101                         }
 102                 }
 103                 cond_resched_rcu();
 104         }
 105         rcu_read_unlock();
 106 }
 107
 108 long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd,
 109                                       struct iommu_group *grp)
 110 {
 111         struct kvmppc_spapr_tce_table *stt = NULL;
 112         bool found = false;
 113         struct iommu_table *tbl = NULL;
 114         struct iommu_table_group *table_group;
 115         long i;
 116         struct kvmppc_spapr_tce_iommu_table *stit;
 117         struct fd f;
 118
 119         f = fdget(tablefd);
 120         if (!f.file)
 121                 return -EBADF;
 122
 123         rcu_read_lock();
 124         list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
 125                 if (stt == f.file->private_data) {
 126                         found = true;
 127                         break;
 128                 }
 129         }
 130         rcu_read_unlock();
 131
 132         fdput(f);
 133
 134         if (!found)
 135                 return -EINVAL;
 136
 137         table_group = iommu_group_get_iommudata(grp);
 138         if (WARN_ON(!table_group))
 139                 return -EFAULT;
 140
 141         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
 142                 struct iommu_table *tbltmp = table_group->tables[i];
 143
 144                 if (!tbltmp)
 145                         continue;
 146                 /* Make sure hardware table parameters are compatible */
 147                 if ((tbltmp->it_page_shift <= stt->page_shift) &&
 148                                 (tbltmp->it_offset << tbltmp->it_page_shift ==
 149                                  stt->offset << stt->page_shift) &&
 150                                 (tbltmp->it_size << tbltmp->it_page_shift >=
 151                                  stt->size << stt->page_shift)) {
 152                         /*
 153                          * Reference the table to avoid races with
 154                          * add/remove DMA windows.
 155                          */
 156                         tbl = iommu_tce_table_get(tbltmp);
 157                         break;
 158                 }
 159         }
 160         if (!tbl)
 161                 return -EINVAL;
 162
 163         rcu_read_lock();
 164         list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
 165                 if (tbl != stit->tbl)
 166                         continue;
 167
 168                 if (!kref_get_unless_zero(&stit->kref)) {
 169                         /* stit is being destroyed */
 170                         iommu_tce_table_put(tbl);
 171                         rcu_read_unlock();
 172                         return -ENOTTY;
 173                 }
 174                 /*
 175                  * The table is already known to this KVM, we just increased
 176                  * its KVM reference counter and can return.
 177                  */
 178                 rcu_read_unlock();
 179                 return 0;
 180         }
 181         rcu_read_unlock();
 182
 183         stit = kzalloc(sizeof(*stit), GFP_KERNEL);
 184         if (!stit) {
 185                 iommu_tce_table_put(tbl);
 186                 return -ENOMEM;
 187         }
 188
 189         stit->tbl = tbl;
 190         kref_init(&stit->kref);
 191
 192         list_add_rcu(&stit->next, &stt->iommu_tables);
 193
 194         return 0;
 195 }
 196
 197 static void release_spapr_tce_table(struct rcu_head *head)
 198 {
 199         struct kvmppc_spapr_tce_table *stt = container_of(head,
 200                         struct kvmppc_spapr_tce_table, rcu);
 201         unsigned long i, npages = kvmppc_tce_pages(stt->size);
 202
 203         for (i = 0; i < npages; i++)
 204                 if (stt->pages[i])
 205                         __free_page(stt->pages[i]);
 206
 207         kfree(stt);
 208 }
 209
 210 static struct page *kvm_spapr_get_tce_page(struct kvmppc_spapr_tce_table *stt,
 211                 unsigned long sttpage)
 212 {
 213         struct page *page = stt->pages[sttpage];
 214
 215         if (page)
 216                 return page;
 217
 218         mutex_lock(&stt->alloc_lock);
 219         page = stt->pages[sttpage];
 220         if (!page) {
 221                 page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 222                 WARN_ON_ONCE(!page);
 223                 if (page)
 224                         stt->pages[sttpage] = page;
 225         }
 226         mutex_unlock(&stt->alloc_lock);
 227
 228         return page;
 229 }
 230
 231 static vm_fault_t kvm_spapr_tce_fault(struct vm_fault *vmf)
 232 {
 233         struct kvmppc_spapr_tce_table *stt = vmf->vma->vm_file->private_data;
 234         struct page *page;
 235
 236         if (vmf->pgoff >= kvmppc_tce_pages(stt->size))
 237                 return VM_FAULT_SIGBUS;
 238
 239         page = kvm_spapr_get_tce_page(stt, vmf->pgoff);
 240         if (!page)
 241                 return VM_FAULT_OOM;
 242
 243         get_page(page);
 244         vmf->page = page;
 245         return 0;
 246 }
 247
 248 static const struct vm_operations_struct kvm_spapr_tce_vm_ops = {
 249         .fault = kvm_spapr_tce_fault,
 250 };
 251
 252 static int kvm_spapr_tce_mmap(struct file *file, struct vm_area_struct *vma)
 253 {
 254         vma->vm_ops = &kvm_spapr_tce_vm_ops;
 255         return 0;
 256 }
 257
 258 static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
 259 {
 260         struct kvmppc_spapr_tce_table *stt = filp->private_data;
 261         struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
 262         struct kvm *kvm = stt->kvm;
 263
 264         mutex_lock(&kvm->lock);
 265         list_del_rcu(&stt->list);
 266         mutex_unlock(&kvm->lock);
 267
 268         list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
 269                 WARN_ON(!kref_read(&stit->kref));
 270                 while (1) {
 271                         if (kref_put(&stit->kref, kvm_spapr_tce_liobn_put))
 272                                 break;
 273                 }
 274         }
 275
 276         account_locked_vm(kvm->mm,
 277                 kvmppc_stt_pages(kvmppc_tce_pages(stt->size)), false);
 278
 279         kvm_put_kvm(stt->kvm);
 280
 281         call_rcu(&stt->rcu, release_spapr_tce_table);
 282
 283         return 0;
 284 }
 285
 286 static const struct file_operations kvm_spapr_tce_fops = {
 287         .mmap           = kvm_spapr_tce_mmap,
 288         .release        = kvm_spapr_tce_release,
 289 };
 290
 291 int kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
 292                                   struct kvm_create_spapr_tce_64 *args)
 293 {
 294         struct kvmppc_spapr_tce_table *stt = NULL;
 295         struct kvmppc_spapr_tce_table *siter;
 296         struct mm_struct *mm = kvm->mm;
 297         unsigned long npages;
 298         int ret;
 299
 300         if (!args->size || args->page_shift < 12 || args->page_shift > 34 ||
 301                 (args->offset + args->size > (ULLONG_MAX >> args->page_shift)))
 302                 return -EINVAL;
 303
 304         npages = kvmppc_tce_pages(args->size);
 305         ret = account_locked_vm(mm, kvmppc_stt_pages(npages), true);
 306         if (ret)
 307                 return ret;
 308
 309         ret = -ENOMEM;
 310         stt = kzalloc(struct_size(stt, pages, npages), GFP_KERNEL | __GFP_NOWARN);
 311         if (!stt)
 312                 goto fail_acct;
 313
 314         stt->liobn = args->liobn;
 315         stt->page_shift = args->page_shift;
 316         stt->offset = args->offset;
 317         stt->size = args->size;
 318         stt->kvm = kvm;
 319         mutex_init(&stt->alloc_lock);
 320         INIT_LIST_HEAD_RCU(&stt->iommu_tables);
 321
 322         mutex_lock(&kvm->lock);
 323
 324         /* Check this LIOBN hasn't been previously allocated */
 325         ret = 0;
 326         list_for_each_entry(siter, &kvm->arch.spapr_tce_tables, list) {
 327                 if (siter->liobn == args->liobn) {
 328                         ret = -EBUSY;
 329                         break;
 330                 }
 331         }
 332
 333         kvm_get_kvm(kvm);
 334         if (!ret)
 335                 ret = anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops,
 336                                        stt, O_RDWR | O_CLOEXEC);
 337
 338         if (ret >= 0)
 339                 list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables);
 340         else
 341                 kvm_put_kvm_no_destroy(kvm);
 342
 343         mutex_unlock(&kvm->lock);
 344
 345         if (ret >= 0)
 346                 return ret;
 347
 348         kfree(stt);
 349  fail_acct:
 350         account_locked_vm(mm, kvmppc_stt_pages(npages), false);
 351         return ret;
 352 }
 353
 354 static long kvmppc_tce_to_ua(struct kvm *kvm, unsigned long tce,
 355                 unsigned long *ua)
 356 {
 357         unsigned long gfn = tce >> PAGE_SHIFT;
 358         struct kvm_memory_slot *memslot;
 359
 360         memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn);
 361         if (!memslot)
 362                 return -EINVAL;
 363
 364         *ua = __gfn_to_hva_memslot(memslot, gfn) |
 365                 (tce & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));
 366
 367         return 0;
 368 }
 369
 370 static long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt,
 371                 unsigned long tce)
 372 {
 373         unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
 374         enum dma_data_direction dir = iommu_tce_direction(tce);
 375         struct kvmppc_spapr_tce_iommu_table *stit;
 376         unsigned long ua = 0;
 377
 378         /* Allow userspace to poison TCE table */
 379         if (dir == DMA_NONE)
 380                 return H_SUCCESS;
 381
 382         if (iommu_tce_check_gpa(stt->page_shift, gpa))
 383                 return H_TOO_HARD;
 384
 385         if (kvmppc_tce_to_ua(stt->kvm, tce, &ua))
 386                 return H_TOO_HARD;
 387
 388         rcu_read_lock();
 389         list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
 390                 unsigned long hpa = 0;
 391                 struct mm_iommu_table_group_mem_t *mem;
 392                 long shift = stit->tbl->it_page_shift;
 393
 394                 mem = mm_iommu_lookup(stt->kvm->mm, ua, 1ULL << shift);
 395                 if (!mem || mm_iommu_ua_to_hpa(mem, ua, shift, &hpa)) {
 396                         rcu_read_unlock();
 397                         return H_TOO_HARD;
 398                 }
 399         }
 400         rcu_read_unlock();
 401
 402         return H_SUCCESS;
 403 }
 404
 405 /*
 406  * Handles TCE requests for emulated devices.
 407  * Puts guest TCE values to the table and expects user space to convert them.
 408  * Cannot fail so kvmppc_tce_validate must be called before it.
 409  */
 410 static void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt,
 411                 unsigned long idx, unsigned long tce)
 412 {
 413         struct page *page;
 414         u64 *tbl;
 415         unsigned long sttpage;
 416
 417         idx -= stt->offset;
 418         sttpage = idx / TCES_PER_PAGE;
 419         page = stt->pages[sttpage];
 420
 421         if (!page) {
 422                 /* We allow any TCE, not just with read|write permissions */
 423                 if (!tce)
 424                         return;
 425
 426                 page = kvm_spapr_get_tce_page(stt, sttpage);
 427                 if (!page)
 428                         return;
 429         }
 430         tbl = page_to_virt(page);
 431
 432         tbl[idx % TCES_PER_PAGE] = tce;
 433 }
 434
 435 static void kvmppc_clear_tce(struct mm_struct *mm, struct kvmppc_spapr_tce_table *stt,
 436                 struct iommu_table *tbl, unsigned long entry)
 437 {
 438         unsigned long i;
 439         unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
 440         unsigned long io_entry = entry << (stt->page_shift - tbl->it_page_shift);
 441
 442         for (i = 0; i < subpages; ++i) {
 443                 unsigned long hpa = 0;
 444                 enum dma_data_direction dir = DMA_NONE;
 445
 446                 iommu_tce_xchg_no_kill(mm, tbl, io_entry + i, &hpa, &dir);
 447         }
 448 }
 449
 450 static long kvmppc_tce_iommu_mapped_dec(struct kvm *kvm,
 451                 struct iommu_table *tbl, unsigned long entry)
 452 {
 453         struct mm_iommu_table_group_mem_t *mem = NULL;
 454         const unsigned long pgsize = 1ULL << tbl->it_page_shift;
 455         __be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY_RO(tbl, entry);
 456
 457         if (!pua)
 458                 return H_SUCCESS;
 459
 460         mem = mm_iommu_lookup(kvm->mm, be64_to_cpu(*pua), pgsize);
 461         if (!mem)
 462                 return H_TOO_HARD;
 463
 464         mm_iommu_mapped_dec(mem);
 465
 466         *pua = cpu_to_be64(0);
 467
 468         return H_SUCCESS;
 469 }
 470
 471 static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm,
 472                 struct iommu_table *tbl, unsigned long entry)
 473 {
 474         enum dma_data_direction dir = DMA_NONE;
 475         unsigned long hpa = 0;
 476         long ret;
 477
 478         if (WARN_ON_ONCE(iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa,
 479                                         &dir)))
 480                 return H_TOO_HARD;
 481
 482         if (dir == DMA_NONE)
 483                 return H_SUCCESS;
 484
 485         ret = kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
 486         if (ret != H_SUCCESS)
 487                 iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
 488
 489         return ret;
 490 }
 491
 492 static long kvmppc_tce_iommu_unmap(struct kvm *kvm,
 493                 struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
 494                 unsigned long entry)
 495 {
 496         unsigned long i, ret = H_SUCCESS;
 497         unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
 498         unsigned long io_entry = entry * subpages;
 499
 500         for (i = 0; i < subpages; ++i) {
 501                 ret = kvmppc_tce_iommu_do_unmap(kvm, tbl, io_entry + i);
 502                 if (ret != H_SUCCESS)
 503                         break;
 504         }
 505
 506         iommu_tce_kill(tbl, io_entry, subpages);
 507
 508         return ret;
 509 }
 510
 511 static long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
 512                 unsigned long entry, unsigned long ua,
 513                 enum dma_data_direction dir)
 514 {
 515         long ret;
 516         unsigned long hpa;
 517         __be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
 518         struct mm_iommu_table_group_mem_t *mem;
 519
 520         if (!pua)
 521                 /* it_userspace allocation might be delayed */
 522                 return H_TOO_HARD;
 523
 524         mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
 525         if (!mem)
 526                 /* This only handles v2 IOMMU type, v1 is handled via ioctl() */
 527                 return H_TOO_HARD;
 528
 529         if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, tbl->it_page_shift, &hpa)))
 530                 return H_TOO_HARD;
 531
 532         if (mm_iommu_mapped_inc(mem))
 533                 return H_TOO_HARD;
 534
 535         ret = iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
 536         if (WARN_ON_ONCE(ret)) {
 537                 mm_iommu_mapped_dec(mem);
 538                 return H_TOO_HARD;
 539         }
 540
 541         if (dir != DMA_NONE)
 542                 kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
 543
 544         *pua = cpu_to_be64(ua);
 545
 546         return 0;
 547 }
 548
 549 static long kvmppc_tce_iommu_map(struct kvm *kvm,
 550                 struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
 551                 unsigned long entry, unsigned long ua,
 552                 enum dma_data_direction dir)
 553 {
 554         unsigned long i, pgoff, ret = H_SUCCESS;
 555         unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
 556         unsigned long io_entry = entry * subpages;
 557
 558         for (i = 0, pgoff = 0; i < subpages;
 559                         ++i, pgoff += IOMMU_PAGE_SIZE(tbl)) {
 560
 561                 ret = kvmppc_tce_iommu_do_map(kvm, tbl,
 562                                 io_entry + i, ua + pgoff, dir);
 563                 if (ret != H_SUCCESS)
 564                         break;
 565         }
 566
 567         iommu_tce_kill(tbl, io_entry, subpages);
 568
 569         return ret;
 570 }
 571
 572 long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
 573                       unsigned long ioba, unsigned long tce)
 574 {
 575         struct kvmppc_spapr_tce_table *stt;
 576         long ret, idx;
 577         struct kvmppc_spapr_tce_iommu_table *stit;
 578         unsigned long entry, ua = 0;
 579         enum dma_data_direction dir;
 580
 581         /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
 582         /*          liobn, ioba, tce); */
 583
 584         stt = kvmppc_find_table(vcpu->kvm, liobn);
 585         if (!stt)
 586                 return H_TOO_HARD;
 587
 588         ret = kvmppc_ioba_validate(stt, ioba, 1);
 589         if (ret != H_SUCCESS)
 590                 return ret;
 591
 592         idx = srcu_read_lock(&vcpu->kvm->srcu);
 593
 594         ret = kvmppc_tce_validate(stt, tce);
 595         if (ret != H_SUCCESS)
 596                 goto unlock_exit;
 597
 598         dir = iommu_tce_direction(tce);
 599
 600         if ((dir != DMA_NONE) && kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
 601                 ret = H_PARAMETER;
 602                 goto unlock_exit;
 603         }
 604
 605         entry = ioba >> stt->page_shift;
 606
 607         list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
 608                 if (dir == DMA_NONE)
 609                         ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
 610                                         stit->tbl, entry);
 611                 else
 612                         ret = kvmppc_tce_iommu_map(vcpu->kvm, stt, stit->tbl,
 613                                         entry, ua, dir);
 614
 615
 616                 if (ret != H_SUCCESS) {
 617                         kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl, entry);
 618                         goto unlock_exit;
 619                 }
 620         }
 621
 622         kvmppc_tce_put(stt, entry, tce);
 623
 624 unlock_exit:
 625         srcu_read_unlock(&vcpu->kvm->srcu, idx);
 626
 627         return ret;
 628 }
 629 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce);
 630
 631 long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
 632                 unsigned long liobn, unsigned long ioba,
 633                 unsigned long tce_list, unsigned long npages)
 634 {
 635         struct kvmppc_spapr_tce_table *stt;
 636         long i, ret = H_SUCCESS, idx;
 637         unsigned long entry, ua = 0;
 638         u64 __user *tces;
 639         u64 tce;
 640         struct kvmppc_spapr_tce_iommu_table *stit;
 641
 642         stt = kvmppc_find_table(vcpu->kvm, liobn);
 643         if (!stt)
 644                 return H_TOO_HARD;
 645
 646         entry = ioba >> stt->page_shift;
 647         /*
 648          * SPAPR spec says that the maximum size of the list is 512 TCEs
 649          * so the whole table fits in 4K page
 650          */
 651         if (npages > 512)
 652                 return H_PARAMETER;
 653
 654         if (tce_list & (SZ_4K - 1))
 655                 return H_PARAMETER;
 656
 657         ret = kvmppc_ioba_validate(stt, ioba, npages);
 658         if (ret != H_SUCCESS)
 659                 return ret;
 660
 661         idx = srcu_read_lock(&vcpu->kvm->srcu);
 662         if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua)) {
 663                 ret = H_TOO_HARD;
 664                 goto unlock_exit;
 665         }
 666         tces = (u64 __user *) ua;
 667
 668         for (i = 0; i < npages; ++i) {
 669                 if (get_user(tce, tces + i)) {
 670                         ret = H_TOO_HARD;
 671                         goto unlock_exit;
 672                 }
 673                 tce = be64_to_cpu(tce);
 674
 675                 ret = kvmppc_tce_validate(stt, tce);
 676                 if (ret != H_SUCCESS)
 677                         goto unlock_exit;
 678         }
 679
 680         for (i = 0; i < npages; ++i) {
 681                 /*
 682                  * This looks unsafe, because we validate, then regrab
 683                  * the TCE from userspace which could have been changed by
 684                  * another thread.
 685                  *
 686                  * But it actually is safe, because the relevant checks will be
 687                  * re-executed in the following code.  If userspace tries to
 688                  * change this dodgily it will result in a messier failure mode
 689                  * but won't threaten the host.
 690                  */
 691                 if (get_user(tce, tces + i)) {
 692                         ret = H_TOO_HARD;
 693                         goto unlock_exit;
 694                 }
 695                 tce = be64_to_cpu(tce);
 696
 697                 if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
 698                         ret = H_PARAMETER;
 699                         goto unlock_exit;
 700                 }
 701
 702                 list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
 703                         ret = kvmppc_tce_iommu_map(vcpu->kvm, stt,
 704                                         stit->tbl, entry + i, ua,
 705                                         iommu_tce_direction(tce));
 706
 707                         if (ret != H_SUCCESS) {
 708                                 kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl,
 709                                                  entry + i);
 710                                 goto unlock_exit;
 711                         }
 712                 }
 713
 714                 kvmppc_tce_put(stt, entry + i, tce);
 715         }
 716
 717 unlock_exit:
 718         srcu_read_unlock(&vcpu->kvm->srcu, idx);
 719
 720         return ret;
 721 }
 722 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce_indirect);
 723
 724 long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
 725                 unsigned long liobn, unsigned long ioba,
 726                 unsigned long tce_value, unsigned long npages)
 727 {
 728         struct kvmppc_spapr_tce_table *stt;
 729         long i, ret;
 730         struct kvmppc_spapr_tce_iommu_table *stit;
 731
 732         stt = kvmppc_find_table(vcpu->kvm, liobn);
 733         if (!stt)
 734                 return H_TOO_HARD;
 735
 736         ret = kvmppc_ioba_validate(stt, ioba, npages);
 737         if (ret != H_SUCCESS)
 738                 return ret;
 739
 740         /* Check permission bits only to allow userspace poison TCE for debug */
 741         if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
 742                 return H_PARAMETER;
 743
 744         list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
 745                 unsigned long entry = ioba >> stt->page_shift;
 746
 747                 for (i = 0; i < npages; ++i) {
 748                         ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
 749                                         stit->tbl, entry + i);
 750
 751                         if (ret == H_SUCCESS)
 752                                 continue;
 753
 754                         if (ret == H_TOO_HARD)
 755                                 return ret;
 756
 757                         WARN_ON_ONCE(1);
 758                         kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl, entry + i);
 759                 }
 760         }
 761
 762         for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
 763                 kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
 764
 765         return ret;
 766 }
 767 EXPORT_SYMBOL_GPL(kvmppc_h_stuff_tce);
 768
 769 long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
 770                       unsigned long ioba)
 771 {
 772         struct kvmppc_spapr_tce_table *stt;
 773         long ret;
 774         unsigned long idx;
 775         struct page *page;
 776         u64 *tbl;
 777
 778         stt = kvmppc_find_table(vcpu->kvm, liobn);
 779         if (!stt)
 780                 return H_TOO_HARD;
 781
 782         ret = kvmppc_ioba_validate(stt, ioba, 1);
 783         if (ret != H_SUCCESS)
 784                 return ret;
 785
 786         idx = (ioba >> stt->page_shift) - stt->offset;
 787         page = stt->pages[idx / TCES_PER_PAGE];
 788         if (!page) {
 789                 kvmppc_set_gpr(vcpu, 4, 0);
 790                 return H_SUCCESS;
 791         }
 792         tbl = (u64 *)page_address(page);
 793
 794         kvmppc_set_gpr(vcpu, 4, tbl[idx % TCES_PER_PAGE]);
 795
 796         return H_SUCCESS;
 797 }
 798 EXPORT_SYMBOL_GPL(kvmppc_h_get_tce);