arch/powerpc/kvm/book3s_64_vio.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License, version 2, as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public License
  12  * along with this program; if not, write to the Free Software
  13  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  14  *
  15  * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
  16  * Copyright 2011 David Gibson, IBM Corporation <dwg@au1.ibm.com>
  17  * Copyright 2016 Alexey Kardashevskiy, IBM Corporation <aik@au1.ibm.com>
  18  */
  19
  20 #include <linux/types.h>
  21 #include <linux/string.h>
  22 #include <linux/kvm.h>
  23 #include <linux/kvm_host.h>
  24 #include <linux/highmem.h>
  25 #include <linux/gfp.h>
  26 #include <linux/slab.h>
  27 #include <linux/sched/signal.h>
  28 #include <linux/hugetlb.h>
  29 #include <linux/list.h>
  30 #include <linux/anon_inodes.h>
  31 #include <linux/iommu.h>
  32 #include <linux/file.h>
  33
  34 #include <asm/tlbflush.h>
  35 #include <asm/kvm_ppc.h>
  36 #include <asm/kvm_book3s.h>
  37 #include <asm/book3s/64/mmu-hash.h>
  38 #include <asm/hvcall.h>
  39 #include <asm/synch.h>
  40 #include <asm/ppc-opcode.h>
  41 #include <asm/kvm_host.h>
  42 #include <asm/udbg.h>
  43 #include <asm/iommu.h>
  44 #include <asm/tce.h>
  45 #include <asm/mmu_context.h>
  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 long kvmppc_account_memlimit(unsigned long stt_pages, bool inc)
  61 {
  62         long ret = 0;
  63
  64         if (!current || !current->mm)
  65                 return ret; /* process exited */
  66
  67         down_write(&current->mm->mmap_sem);
  68
  69         if (inc) {
  70                 unsigned long locked, lock_limit;
  71
  72                 locked = current->mm->locked_vm + stt_pages;
  73                 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
  74                 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
  75                         ret = -ENOMEM;
  76                 else
  77                         current->mm->locked_vm += stt_pages;
  78         } else {
  79                 if (WARN_ON_ONCE(stt_pages > current->mm->locked_vm))
  80                         stt_pages = current->mm->locked_vm;
  81
  82                 current->mm->locked_vm -= stt_pages;
  83         }
  84
  85         pr_debug("[%d] RLIMIT_MEMLOCK KVM %c%ld %ld/%ld%s\n", current->pid,
  86                         inc ? '+' : '-',
  87                         stt_pages << PAGE_SHIFT,
  88                         current->mm->locked_vm << PAGE_SHIFT,
  89                         rlimit(RLIMIT_MEMLOCK),
  90                         ret ? " - exceeded" : "");
  91
  92         up_write(&current->mm->mmap_sem);
  93
  94         return ret;
  95 }
  96
  97 static void kvm_spapr_tce_iommu_table_free(struct rcu_head *head)
  98 {
  99         struct kvmppc_spapr_tce_iommu_table *stit = container_of(head,
 100                         struct kvmppc_spapr_tce_iommu_table, rcu);
 101
 102         iommu_tce_table_put(stit->tbl);
 103
 104         kfree(stit);
 105 }
 106
 107 static void kvm_spapr_tce_liobn_put(struct kref *kref)
 108 {
 109         struct kvmppc_spapr_tce_iommu_table *stit = container_of(kref,
 110                         struct kvmppc_spapr_tce_iommu_table, kref);
 111
 112         list_del_rcu(&stit->next);
 113
 114         call_rcu(&stit->rcu, kvm_spapr_tce_iommu_table_free);
 115 }
 116
 117 extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
 118                 struct iommu_group *grp)
 119 {
 120         int i;
 121         struct kvmppc_spapr_tce_table *stt;
 122         struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
 123         struct iommu_table_group *table_group = NULL;
 124
 125         list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
 126
 127                 table_group = iommu_group_get_iommudata(grp);
 128                 if (WARN_ON(!table_group))
 129                         continue;
 130
 131                 list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
 132                         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
 133                                 if (table_group->tables[i] != stit->tbl)
 134                                         continue;
 135
 136                                 kref_put(&stit->kref, kvm_spapr_tce_liobn_put);
 137                         }
 138                 }
 139         }
 140 }
 141
 142 extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd,
 143                 struct iommu_group *grp)
 144 {
 145         struct kvmppc_spapr_tce_table *stt = NULL;
 146         bool found = false;
 147         struct iommu_table *tbl = NULL;
 148         struct iommu_table_group *table_group;
 149         long i;
 150         struct kvmppc_spapr_tce_iommu_table *stit;
 151         struct fd f;
 152
 153         f = fdget(tablefd);
 154         if (!f.file)
 155                 return -EBADF;
 156
 157         list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
 158                 if (stt == f.file->private_data) {
 159                         found = true;
 160                         break;
 161                 }
 162         }
 163
 164         fdput(f);
 165
 166         if (!found)
 167                 return -EINVAL;
 168
 169         table_group = iommu_group_get_iommudata(grp);
 170         if (WARN_ON(!table_group))
 171                 return -EFAULT;
 172
 173         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
 174                 struct iommu_table *tbltmp = table_group->tables[i];
 175
 176                 if (!tbltmp)
 177                         continue;
 178                 /*
 179                  * Make sure hardware table parameters are exactly the same;
 180                  * this is used in the TCE handlers where boundary checks
 181                  * use only the first attached table.
 182                  */
 183                 if ((tbltmp->it_page_shift == stt->page_shift) &&
 184                                 (tbltmp->it_offset == stt->offset) &&
 185                                 (tbltmp->it_size == stt->size)) {
 186                         /*
 187                          * Reference the table to avoid races with
 188                          * add/remove DMA windows.
 189                          */
 190                         tbl = iommu_tce_table_get(tbltmp);
 191                         break;
 192                 }
 193         }
 194         if (!tbl)
 195                 return -EINVAL;
 196
 197         list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
 198                 if (tbl != stit->tbl)
 199                         continue;
 200
 201                 if (!kref_get_unless_zero(&stit->kref)) {
 202                         /* stit is being destroyed */
 203                         iommu_tce_table_put(tbl);
 204                         return -ENOTTY;
 205                 }
 206                 /*
 207                  * The table is already known to this KVM, we just increased
 208                  * its KVM reference counter and can return.
 209                  */
 210                 return 0;
 211         }
 212
 213         stit = kzalloc(sizeof(*stit), GFP_KERNEL);
 214         if (!stit) {
 215                 iommu_tce_table_put(tbl);
 216                 return -ENOMEM;
 217         }
 218
 219         stit->tbl = tbl;
 220         kref_init(&stit->kref);
 221
 222         list_add_rcu(&stit->next, &stt->iommu_tables);
 223
 224         return 0;
 225 }
 226
 227 static void release_spapr_tce_table(struct rcu_head *head)
 228 {
 229         struct kvmppc_spapr_tce_table *stt = container_of(head,
 230                         struct kvmppc_spapr_tce_table, rcu);
 231         unsigned long i, npages = kvmppc_tce_pages(stt->size);
 232
 233         for (i = 0; i < npages; i++)
 234                 __free_page(stt->pages[i]);
 235
 236         kfree(stt);
 237 }
 238
 239 static int kvm_spapr_tce_fault(struct vm_fault *vmf)
 240 {
 241         struct kvmppc_spapr_tce_table *stt = vmf->vma->vm_file->private_data;
 242         struct page *page;
 243
 244         if (vmf->pgoff >= kvmppc_tce_pages(stt->size))
 245                 return VM_FAULT_SIGBUS;
 246
 247         page = stt->pages[vmf->pgoff];
 248         get_page(page);
 249         vmf->page = page;
 250         return 0;
 251 }
 252
 253 static const struct vm_operations_struct kvm_spapr_tce_vm_ops = {
 254         .fault = kvm_spapr_tce_fault,
 255 };
 256
 257 static int kvm_spapr_tce_mmap(struct file *file, struct vm_area_struct *vma)
 258 {
 259         vma->vm_ops = &kvm_spapr_tce_vm_ops;
 260         return 0;
 261 }
 262
 263 static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
 264 {
 265         struct kvmppc_spapr_tce_table *stt = filp->private_data;
 266         struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
 267         struct kvm *kvm = stt->kvm;
 268
 269         mutex_lock(&kvm->lock);
 270         list_del_rcu(&stt->list);
 271         mutex_unlock(&kvm->lock);
 272
 273         list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
 274                 WARN_ON(!kref_read(&stit->kref));
 275                 while (1) {
 276                         if (kref_put(&stit->kref, kvm_spapr_tce_liobn_put))
 277                                 break;
 278                 }
 279         }
 280
 281         kvm_put_kvm(stt->kvm);
 282
 283         kvmppc_account_memlimit(
 284                 kvmppc_stt_pages(kvmppc_tce_pages(stt->size)), false);
 285         call_rcu(&stt->rcu, release_spapr_tce_table);
 286
 287         return 0;
 288 }
 289
 290 static const struct file_operations kvm_spapr_tce_fops = {
 291         .mmap           = kvm_spapr_tce_mmap,
 292         .release        = kvm_spapr_tce_release,
 293 };
 294
 295 long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
 296                                    struct kvm_create_spapr_tce_64 *args)
 297 {
 298         struct kvmppc_spapr_tce_table *stt = NULL;
 299         struct kvmppc_spapr_tce_table *siter;
 300         unsigned long npages, size;
 301         int ret = -ENOMEM;
 302         int i;
 303
 304         if (!args->size)
 305                 return -EINVAL;
 306
 307         size = _ALIGN_UP(args->size, PAGE_SIZE >> 3);
 308         npages = kvmppc_tce_pages(size);
 309         ret = kvmppc_account_memlimit(kvmppc_stt_pages(npages), true);
 310         if (ret)
 311                 return ret;
 312
 313         ret = -ENOMEM;
 314         stt = kzalloc(sizeof(*stt) + npages * sizeof(struct page *),
 315                       GFP_KERNEL);
 316         if (!stt)
 317                 goto fail_acct;
 318
 319         stt->liobn = args->liobn;
 320         stt->page_shift = args->page_shift;
 321         stt->offset = args->offset;
 322         stt->size = size;
 323         stt->kvm = kvm;
 324         INIT_LIST_HEAD_RCU(&stt->iommu_tables);
 325
 326         for (i = 0; i < npages; i++) {
 327                 stt->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO);
 328                 if (!stt->pages[i])
 329                         goto fail;
 330         }
 331
 332         mutex_lock(&kvm->lock);
 333
 334         /* Check this LIOBN hasn't been previously allocated */
 335         ret = 0;
 336         list_for_each_entry(siter, &kvm->arch.spapr_tce_tables, list) {
 337                 if (siter->liobn == args->liobn) {
 338                         ret = -EBUSY;
 339                         break;
 340                 }
 341         }
 342
 343         if (!ret)
 344                 ret = anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops,
 345                                        stt, O_RDWR | O_CLOEXEC);
 346
 347         if (ret >= 0) {
 348                 list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables);
 349                 kvm_get_kvm(kvm);
 350         }
 351
 352         mutex_unlock(&kvm->lock);
 353
 354         if (ret >= 0)
 355                 return ret;
 356
 357  fail:
 358         for (i = 0; i < npages; i++)
 359                 if (stt->pages[i])
 360                         __free_page(stt->pages[i]);
 361
 362         kfree(stt);
 363  fail_acct:
 364         kvmppc_account_memlimit(kvmppc_stt_pages(npages), false);
 365         return ret;
 366 }
 367
 368 static void kvmppc_clear_tce(struct iommu_table *tbl, unsigned long entry)
 369 {
 370         unsigned long hpa = 0;
 371         enum dma_data_direction dir = DMA_NONE;
 372
 373         iommu_tce_xchg(tbl, entry, &hpa, &dir);
 374 }
 375
 376 static long kvmppc_tce_iommu_mapped_dec(struct kvm *kvm,
 377                 struct iommu_table *tbl, unsigned long entry)
 378 {
 379         struct mm_iommu_table_group_mem_t *mem = NULL;
 380         const unsigned long pgsize = 1ULL << tbl->it_page_shift;
 381         unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
 382
 383         if (!pua)
 384                 /* it_userspace allocation might be delayed */
 385                 return H_TOO_HARD;
 386
 387         mem = mm_iommu_lookup(kvm->mm, *pua, pgsize);
 388         if (!mem)
 389                 return H_TOO_HARD;
 390
 391         mm_iommu_mapped_dec(mem);
 392
 393         *pua = 0;
 394
 395         return H_SUCCESS;
 396 }
 397
 398 static long kvmppc_tce_iommu_unmap(struct kvm *kvm,
 399                 struct iommu_table *tbl, unsigned long entry)
 400 {
 401         enum dma_data_direction dir = DMA_NONE;
 402         unsigned long hpa = 0;
 403         long ret;
 404
 405         if (WARN_ON_ONCE(iommu_tce_xchg(tbl, entry, &hpa, &dir)))
 406                 return H_TOO_HARD;
 407
 408         if (dir == DMA_NONE)
 409                 return H_SUCCESS;
 410
 411         ret = kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
 412         if (ret != H_SUCCESS)
 413                 iommu_tce_xchg(tbl, entry, &hpa, &dir);
 414
 415         return ret;
 416 }
 417
 418 long kvmppc_tce_iommu_map(struct kvm *kvm, struct iommu_table *tbl,
 419                 unsigned long entry, unsigned long ua,
 420                 enum dma_data_direction dir)
 421 {
 422         long ret;
 423         unsigned long hpa, *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
 424         struct mm_iommu_table_group_mem_t *mem;
 425
 426         if (!pua)
 427                 /* it_userspace allocation might be delayed */
 428                 return H_TOO_HARD;
 429
 430         mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
 431         if (!mem)
 432                 /* This only handles v2 IOMMU type, v1 is handled via ioctl() */
 433                 return H_TOO_HARD;
 434
 435         if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, tbl->it_page_shift, &hpa)))
 436                 return H_TOO_HARD;
 437
 438         if (mm_iommu_mapped_inc(mem))
 439                 return H_TOO_HARD;
 440
 441         ret = iommu_tce_xchg(tbl, entry, &hpa, &dir);
 442         if (WARN_ON_ONCE(ret)) {
 443                 mm_iommu_mapped_dec(mem);
 444                 return H_TOO_HARD;
 445         }
 446
 447         if (dir != DMA_NONE)
 448                 kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
 449
 450         *pua = ua;
 451
 452         return 0;
 453 }
 454
 455 long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
 456                       unsigned long ioba, unsigned long tce)
 457 {
 458         struct kvmppc_spapr_tce_table *stt;
 459         long ret, idx;
 460         struct kvmppc_spapr_tce_iommu_table *stit;
 461         unsigned long entry, ua = 0;
 462         enum dma_data_direction dir;
 463
 464         /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
 465         /*          liobn, ioba, tce); */
 466
 467         stt = kvmppc_find_table(vcpu->kvm, liobn);
 468         if (!stt)
 469                 return H_TOO_HARD;
 470
 471         ret = kvmppc_ioba_validate(stt, ioba, 1);
 472         if (ret != H_SUCCESS)
 473                 return ret;
 474
 475         ret = kvmppc_tce_validate(stt, tce);
 476         if (ret != H_SUCCESS)
 477                 return ret;
 478
 479         dir = iommu_tce_direction(tce);
 480
 481         idx = srcu_read_lock(&vcpu->kvm->srcu);
 482
 483         if ((dir != DMA_NONE) && kvmppc_gpa_to_ua(vcpu->kvm,
 484                         tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), &ua, NULL)) {
 485                 ret = H_PARAMETER;
 486                 goto unlock_exit;
 487         }
 488
 489         entry = ioba >> stt->page_shift;
 490
 491         list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
 492                 if (dir == DMA_NONE)
 493                         ret = kvmppc_tce_iommu_unmap(vcpu->kvm,
 494                                         stit->tbl, entry);
 495                 else
 496                         ret = kvmppc_tce_iommu_map(vcpu->kvm, stit->tbl,
 497                                         entry, ua, dir);
 498
 499                 if (ret == H_SUCCESS)
 500                         continue;
 501
 502                 if (ret == H_TOO_HARD)
 503                         goto unlock_exit;
 504
 505                 WARN_ON_ONCE(1);
 506                 kvmppc_clear_tce(stit->tbl, entry);
 507         }
 508
 509         kvmppc_tce_put(stt, entry, tce);
 510
 511 unlock_exit:
 512         srcu_read_unlock(&vcpu->kvm->srcu, idx);
 513
 514         return ret;
 515 }
 516 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce);
 517
 518 long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
 519                 unsigned long liobn, unsigned long ioba,
 520                 unsigned long tce_list, unsigned long npages)
 521 {
 522         struct kvmppc_spapr_tce_table *stt;
 523         long i, ret = H_SUCCESS, idx;
 524         unsigned long entry, ua = 0;
 525         u64 __user *tces;
 526         u64 tce;
 527         struct kvmppc_spapr_tce_iommu_table *stit;
 528
 529         stt = kvmppc_find_table(vcpu->kvm, liobn);
 530         if (!stt)
 531                 return H_TOO_HARD;
 532
 533         entry = ioba >> stt->page_shift;
 534         /*
 535          * SPAPR spec says that the maximum size of the list is 512 TCEs
 536          * so the whole table fits in 4K page
 537          */
 538         if (npages > 512)
 539                 return H_PARAMETER;
 540
 541         if (tce_list & (SZ_4K - 1))
 542                 return H_PARAMETER;
 543
 544         ret = kvmppc_ioba_validate(stt, ioba, npages);
 545         if (ret != H_SUCCESS)
 546                 return ret;
 547
 548         idx = srcu_read_lock(&vcpu->kvm->srcu);
 549         if (kvmppc_gpa_to_ua(vcpu->kvm, tce_list, &ua, NULL)) {
 550                 ret = H_TOO_HARD;
 551                 goto unlock_exit;
 552         }
 553         tces = (u64 __user *) ua;
 554
 555         for (i = 0; i < npages; ++i) {
 556                 if (get_user(tce, tces + i)) {
 557                         ret = H_TOO_HARD;
 558                         goto unlock_exit;
 559                 }
 560                 tce = be64_to_cpu(tce);
 561
 562                 ret = kvmppc_tce_validate(stt, tce);
 563                 if (ret != H_SUCCESS)
 564                         goto unlock_exit;
 565
 566                 if (kvmppc_gpa_to_ua(vcpu->kvm,
 567                                 tce & ~(TCE_PCI_READ | TCE_PCI_WRITE),
 568                                 &ua, NULL)) {
 569                         ret = H_PARAMETER;
 570                         goto unlock_exit;
 571                 }
 572
 573                 list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
 574                         ret = kvmppc_tce_iommu_map(vcpu->kvm,
 575                                         stit->tbl, entry + i, ua,
 576                                         iommu_tce_direction(tce));
 577
 578                         if (ret == H_SUCCESS)
 579                                 continue;
 580
 581                         if (ret == H_TOO_HARD)
 582                                 goto unlock_exit;
 583
 584                         WARN_ON_ONCE(1);
 585                         kvmppc_clear_tce(stit->tbl, entry);
 586                 }
 587
 588                 kvmppc_tce_put(stt, entry + i, tce);
 589         }
 590
 591 unlock_exit:
 592         srcu_read_unlock(&vcpu->kvm->srcu, idx);
 593
 594         return ret;
 595 }
 596 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce_indirect);
 597
 598 long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
 599                 unsigned long liobn, unsigned long ioba,
 600                 unsigned long tce_value, unsigned long npages)
 601 {
 602         struct kvmppc_spapr_tce_table *stt;
 603         long i, ret;
 604         struct kvmppc_spapr_tce_iommu_table *stit;
 605
 606         stt = kvmppc_find_table(vcpu->kvm, liobn);
 607         if (!stt)
 608                 return H_TOO_HARD;
 609
 610         ret = kvmppc_ioba_validate(stt, ioba, npages);
 611         if (ret != H_SUCCESS)
 612                 return ret;
 613
 614         /* Check permission bits only to allow userspace poison TCE for debug */
 615         if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
 616                 return H_PARAMETER;
 617
 618         list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
 619                 unsigned long entry = ioba >> stit->tbl->it_page_shift;
 620
 621                 for (i = 0; i < npages; ++i) {
 622                         ret = kvmppc_tce_iommu_unmap(vcpu->kvm,
 623                                         stit->tbl, entry + i);
 624
 625                         if (ret == H_SUCCESS)
 626                                 continue;
 627
 628                         if (ret == H_TOO_HARD)
 629                                 return ret;
 630
 631                         WARN_ON_ONCE(1);
 632                         kvmppc_clear_tce(stit->tbl, entry);
 633                 }
 634         }
 635
 636         for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
 637                 kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
 638
 639         return H_SUCCESS;
 640 }
 641 EXPORT_SYMBOL_GPL(kvmppc_h_stuff_tce);