drivers/gpu/drm/nouveau/nouveau_svm.c

   1 /*
   2  * Copyright 2018 Red Hat Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20  * OTHER DEALINGS IN THE SOFTWARE.
  21  */
  22 #include "nouveau_svm.h"
  23 #include "nouveau_drv.h"
  24 #include "nouveau_chan.h"
  25 #include "nouveau_dmem.h"
  26
  27 #include <nvif/notify.h>
  28 #include <nvif/object.h>
  29 #include <nvif/vmm.h>
  30
  31 #include <nvif/class.h>
  32 #include <nvif/clb069.h>
  33 #include <nvif/ifc00d.h>
  34
  35 #include <linux/sched/mm.h>
  36 #include <linux/sort.h>
  37 #include <linux/hmm.h>
  38
  39 struct nouveau_svm {
  40         struct nouveau_drm *drm;
  41         struct mutex mutex;
  42         struct list_head inst;
  43
  44         struct nouveau_svm_fault_buffer {
  45                 int id;
  46                 struct nvif_object object;
  47                 u32 entries;
  48                 u32 getaddr;
  49                 u32 putaddr;
  50                 u32 get;
  51                 u32 put;
  52                 struct nvif_notify notify;
  53
  54                 struct nouveau_svm_fault {
  55                         u64 inst;
  56                         u64 addr;
  57                         u64 time;
  58                         u32 engine;
  59                         u8  gpc;
  60                         u8  hub;
  61                         u8  access;
  62                         u8  client;
  63                         u8  fault;
  64                         struct nouveau_svmm *svmm;
  65                 } **fault;
  66                 int fault_nr;
  67         } buffer[1];
  68 };
  69
  70 #define SVM_DBG(s,f,a...) NV_DEBUG((s)->drm, "svm: "f"\n", ##a)
  71 #define SVM_ERR(s,f,a...) NV_WARN((s)->drm, "svm: "f"\n", ##a)
  72
  73 struct nouveau_ivmm {
  74         struct nouveau_svmm *svmm;
  75         u64 inst;
  76         struct list_head head;
  77 };
  78
  79 static struct nouveau_ivmm *
  80 nouveau_ivmm_find(struct nouveau_svm *svm, u64 inst)
  81 {
  82         struct nouveau_ivmm *ivmm;
  83         list_for_each_entry(ivmm, &svm->inst, head) {
  84                 if (ivmm->inst == inst)
  85                         return ivmm;
  86         }
  87         return NULL;
  88 }
  89
  90 struct nouveau_svmm {
  91         struct mmu_notifier notifier;
  92         struct nouveau_vmm *vmm;
  93         struct {
  94                 unsigned long start;
  95                 unsigned long limit;
  96         } unmanaged;
  97
  98         struct mutex mutex;
  99 };
 100
 101 #define SVMM_DBG(s,f,a...)                                                     \
 102         NV_DEBUG((s)->vmm->cli->drm, "svm-%p: "f"\n", (s), ##a)
 103 #define SVMM_ERR(s,f,a...)                                                     \
 104         NV_WARN((s)->vmm->cli->drm, "svm-%p: "f"\n", (s), ##a)
 105
 106 int
 107 nouveau_svmm_bind(struct drm_device *dev, void *data,
 108                   struct drm_file *file_priv)
 109 {
 110         struct nouveau_cli *cli = nouveau_cli(file_priv);
 111         struct drm_nouveau_svm_bind *args = data;
 112         unsigned target, cmd, priority;
 113         unsigned long addr, end, size;
 114         struct mm_struct *mm;
 115
 116         args->va_start &= PAGE_MASK;
 117         args->va_end &= PAGE_MASK;
 118
 119         /* Sanity check arguments */
 120         if (args->reserved0 || args->reserved1)
 121                 return -EINVAL;
 122         if (args->header & (~NOUVEAU_SVM_BIND_VALID_MASK))
 123                 return -EINVAL;
 124         if (args->va_start >= args->va_end)
 125                 return -EINVAL;
 126         if (!args->npages)
 127                 return -EINVAL;
 128
 129         cmd = args->header >> NOUVEAU_SVM_BIND_COMMAND_SHIFT;
 130         cmd &= NOUVEAU_SVM_BIND_COMMAND_MASK;
 131         switch (cmd) {
 132         case NOUVEAU_SVM_BIND_COMMAND__MIGRATE:
 133                 break;
 134         default:
 135                 return -EINVAL;
 136         }
 137
 138         priority = args->header >> NOUVEAU_SVM_BIND_PRIORITY_SHIFT;
 139         priority &= NOUVEAU_SVM_BIND_PRIORITY_MASK;
 140
 141         /* FIXME support CPU target ie all target value < GPU_VRAM */
 142         target = args->header >> NOUVEAU_SVM_BIND_TARGET_SHIFT;
 143         target &= NOUVEAU_SVM_BIND_TARGET_MASK;
 144         switch (target) {
 145         case NOUVEAU_SVM_BIND_TARGET__GPU_VRAM:
 146                 break;
 147         default:
 148                 return -EINVAL;
 149         }
 150
 151         /*
 152          * FIXME: For now refuse non 0 stride, we need to change the migrate
 153          * kernel function to handle stride to avoid to create a mess within
 154          * each device driver.
 155          */
 156         if (args->stride)
 157                 return -EINVAL;
 158
 159         size = ((unsigned long)args->npages) << PAGE_SHIFT;
 160         if ((args->va_start + size) <= args->va_start)
 161                 return -EINVAL;
 162         if ((args->va_start + size) > args->va_end)
 163                 return -EINVAL;
 164
 165         /*
 166          * Ok we are ask to do something sane, for now we only support migrate
 167          * commands but we will add things like memory policy (what to do on
 168          * page fault) and maybe some other commands.
 169          */
 170
 171         mm = get_task_mm(current);
 172         down_read(&mm->mmap_sem);
 173
 174         for (addr = args->va_start, end = args->va_start + size; addr < end;) {
 175                 struct vm_area_struct *vma;
 176                 unsigned long next;
 177
 178                 vma = find_vma_intersection(mm, addr, end);
 179                 if (!vma)
 180                         break;
 181
 182                 next = min(vma->vm_end, end);
 183                 /* This is a best effort so we ignore errors */
 184                 nouveau_dmem_migrate_vma(cli->drm, vma, addr, next);
 185                 addr = next;
 186         }
 187
 188         /*
 189          * FIXME Return the number of page we have migrated, again we need to
 190          * update the migrate API to return that information so that we can
 191          * report it to user space.
 192          */
 193         args->result = 0;
 194
 195         up_read(&mm->mmap_sem);
 196         mmput(mm);
 197
 198         return 0;
 199 }
 200
 201 /* Unlink channel instance from SVMM. */
 202 void
 203 nouveau_svmm_part(struct nouveau_svmm *svmm, u64 inst)
 204 {
 205         struct nouveau_ivmm *ivmm;
 206         if (svmm) {
 207                 mutex_lock(&svmm->vmm->cli->drm->svm->mutex);
 208                 ivmm = nouveau_ivmm_find(svmm->vmm->cli->drm->svm, inst);
 209                 if (ivmm) {
 210                         list_del(&ivmm->head);
 211                         kfree(ivmm);
 212                 }
 213                 mutex_unlock(&svmm->vmm->cli->drm->svm->mutex);
 214         }
 215 }
 216
 217 /* Link channel instance to SVMM. */
 218 int
 219 nouveau_svmm_join(struct nouveau_svmm *svmm, u64 inst)
 220 {
 221         struct nouveau_ivmm *ivmm;
 222         if (svmm) {
 223                 if (!(ivmm = kmalloc(sizeof(*ivmm), GFP_KERNEL)))
 224                         return -ENOMEM;
 225                 ivmm->svmm = svmm;
 226                 ivmm->inst = inst;
 227
 228                 mutex_lock(&svmm->vmm->cli->drm->svm->mutex);
 229                 list_add(&ivmm->head, &svmm->vmm->cli->drm->svm->inst);
 230                 mutex_unlock(&svmm->vmm->cli->drm->svm->mutex);
 231         }
 232         return 0;
 233 }
 234
 235 /* Invalidate SVMM address-range on GPU. */
 236 static void
 237 nouveau_svmm_invalidate(struct nouveau_svmm *svmm, u64 start, u64 limit)
 238 {
 239         if (limit > start) {
 240                 bool super = svmm->vmm->vmm.object.client->super;
 241                 svmm->vmm->vmm.object.client->super = true;
 242                 nvif_object_mthd(&svmm->vmm->vmm.object, NVIF_VMM_V0_PFNCLR,
 243                                  &(struct nvif_vmm_pfnclr_v0) {
 244                                         .addr = start,
 245                                         .size = limit - start,
 246                                  }, sizeof(struct nvif_vmm_pfnclr_v0));
 247                 svmm->vmm->vmm.object.client->super = super;
 248         }
 249 }
 250
 251 static int
 252 nouveau_svmm_invalidate_range_start(struct mmu_notifier *mn,
 253                                     const struct mmu_notifier_range *update)
 254 {
 255         struct nouveau_svmm *svmm =
 256                 container_of(mn, struct nouveau_svmm, notifier);
 257         unsigned long start = update->start;
 258         unsigned long limit = update->end;
 259
 260         if (!mmu_notifier_range_blockable(update))
 261                 return -EAGAIN;
 262
 263         SVMM_DBG(svmm, "invalidate %016lx-%016lx", start, limit);
 264
 265         mutex_lock(&svmm->mutex);
 266         if (unlikely(!svmm->vmm))
 267                 goto out;
 268
 269         if (limit > svmm->unmanaged.start && start < svmm->unmanaged.limit) {
 270                 if (start < svmm->unmanaged.start) {
 271                         nouveau_svmm_invalidate(svmm, start,
 272                                                 svmm->unmanaged.limit);
 273                 }
 274                 start = svmm->unmanaged.limit;
 275         }
 276
 277         nouveau_svmm_invalidate(svmm, start, limit);
 278
 279 out:
 280         mutex_unlock(&svmm->mutex);
 281         return 0;
 282 }
 283
 284 static void nouveau_svmm_free_notifier(struct mmu_notifier *mn)
 285 {
 286         kfree(container_of(mn, struct nouveau_svmm, notifier));
 287 }
 288
 289 static const struct mmu_notifier_ops nouveau_mn_ops = {
 290         .invalidate_range_start = nouveau_svmm_invalidate_range_start,
 291         .free_notifier = nouveau_svmm_free_notifier,
 292 };
 293
 294 void
 295 nouveau_svmm_fini(struct nouveau_svmm **psvmm)
 296 {
 297         struct nouveau_svmm *svmm = *psvmm;
 298         if (svmm) {
 299                 mutex_lock(&svmm->mutex);
 300                 svmm->vmm = NULL;
 301                 mutex_unlock(&svmm->mutex);
 302                 mmu_notifier_put(&svmm->notifier);
 303                 *psvmm = NULL;
 304         }
 305 }
 306
 307 int
 308 nouveau_svmm_init(struct drm_device *dev, void *data,
 309                   struct drm_file *file_priv)
 310 {
 311         struct nouveau_cli *cli = nouveau_cli(file_priv);
 312         struct nouveau_svmm *svmm;
 313         struct drm_nouveau_svm_init *args = data;
 314         int ret;
 315
 316         /* Allocate tracking for SVM-enabled VMM. */
 317         if (!(svmm = kzalloc(sizeof(*svmm), GFP_KERNEL)))
 318                 return -ENOMEM;
 319         svmm->vmm = &cli->svm;
 320         svmm->unmanaged.start = args->unmanaged_addr;
 321         svmm->unmanaged.limit = args->unmanaged_addr + args->unmanaged_size;
 322         mutex_init(&svmm->mutex);
 323
 324         /* Check that SVM isn't already enabled for the client. */
 325         mutex_lock(&cli->mutex);
 326         if (cli->svm.cli) {
 327                 ret = -EBUSY;
 328                 goto out_free;
 329         }
 330
 331         /* Allocate a new GPU VMM that can support SVM (managed by the
 332          * client, with replayable faults enabled).
 333          *
 334          * All future channel/memory allocations will make use of this
 335          * VMM instead of the standard one.
 336          */
 337         ret = nvif_vmm_init(&cli->mmu, cli->vmm.vmm.object.oclass, true,
 338                             args->unmanaged_addr, args->unmanaged_size,
 339                             &(struct gp100_vmm_v0) {
 340                                 .fault_replay = true,
 341                             }, sizeof(struct gp100_vmm_v0), &cli->svm.vmm);
 342         if (ret)
 343                 goto out_free;
 344
 345         down_write(&current->mm->mmap_sem);
 346         svmm->notifier.ops = &nouveau_mn_ops;
 347         ret = __mmu_notifier_register(&svmm->notifier, current->mm);
 348         if (ret)
 349                 goto out_mm_unlock;
 350         /* Note, ownership of svmm transfers to mmu_notifier */
 351
 352         cli->svm.svmm = svmm;
 353         cli->svm.cli = cli;
 354         up_write(&current->mm->mmap_sem);
 355         mutex_unlock(&cli->mutex);
 356         return 0;
 357
 358 out_mm_unlock:
 359         up_write(&current->mm->mmap_sem);
 360 out_free:
 361         mutex_unlock(&cli->mutex);
 362         kfree(svmm);
 363         return ret;
 364 }
 365
 366 static const u64
 367 nouveau_svm_pfn_flags[HMM_PFN_FLAG_MAX] = {
 368         [HMM_PFN_VALID         ] = NVIF_VMM_PFNMAP_V0_V,
 369         [HMM_PFN_WRITE         ] = NVIF_VMM_PFNMAP_V0_W,
 370         [HMM_PFN_DEVICE_PRIVATE] = NVIF_VMM_PFNMAP_V0_VRAM,
 371 };
 372
 373 static const u64
 374 nouveau_svm_pfn_values[HMM_PFN_VALUE_MAX] = {
 375         [HMM_PFN_ERROR  ] = ~NVIF_VMM_PFNMAP_V0_V,
 376         [HMM_PFN_NONE   ] =  NVIF_VMM_PFNMAP_V0_NONE,
 377         [HMM_PFN_SPECIAL] = ~NVIF_VMM_PFNMAP_V0_V,
 378 };
 379
 380 /* Issue fault replay for GPU to retry accesses that faulted previously. */
 381 static void
 382 nouveau_svm_fault_replay(struct nouveau_svm *svm)
 383 {
 384         SVM_DBG(svm, "replay");
 385         WARN_ON(nvif_object_mthd(&svm->drm->client.vmm.vmm.object,
 386                                  GP100_VMM_VN_FAULT_REPLAY,
 387                                  &(struct gp100_vmm_fault_replay_vn) {},
 388                                  sizeof(struct gp100_vmm_fault_replay_vn)));
 389 }
 390
 391 /* Cancel a replayable fault that could not be handled.
 392  *
 393  * Cancelling the fault will trigger recovery to reset the engine
 394  * and kill the offending channel (ie. GPU SIGSEGV).
 395  */
 396 static void
 397 nouveau_svm_fault_cancel(struct nouveau_svm *svm,
 398                          u64 inst, u8 hub, u8 gpc, u8 client)
 399 {
 400         SVM_DBG(svm, "cancel %016llx %d %02x %02x", inst, hub, gpc, client);
 401         WARN_ON(nvif_object_mthd(&svm->drm->client.vmm.vmm.object,
 402                                  GP100_VMM_VN_FAULT_CANCEL,
 403                                  &(struct gp100_vmm_fault_cancel_v0) {
 404                                         .hub = hub,
 405                                         .gpc = gpc,
 406                                         .client = client,
 407                                         .inst = inst,
 408                                  }, sizeof(struct gp100_vmm_fault_cancel_v0)));
 409 }
 410
 411 static void
 412 nouveau_svm_fault_cancel_fault(struct nouveau_svm *svm,
 413                                struct nouveau_svm_fault *fault)
 414 {
 415         nouveau_svm_fault_cancel(svm, fault->inst,
 416                                       fault->hub,
 417                                       fault->gpc,
 418                                       fault->client);
 419 }
 420
 421 static int
 422 nouveau_svm_fault_cmp(const void *a, const void *b)
 423 {
 424         const struct nouveau_svm_fault *fa = *(struct nouveau_svm_fault **)a;
 425         const struct nouveau_svm_fault *fb = *(struct nouveau_svm_fault **)b;
 426         int ret;
 427         if ((ret = (s64)fa->inst - fb->inst))
 428                 return ret;
 429         if ((ret = (s64)fa->addr - fb->addr))
 430                 return ret;
 431         /*XXX: atomic? */
 432         return (fa->access == 0 || fa->access == 3) -
 433                (fb->access == 0 || fb->access == 3);
 434 }
 435
 436 static void
 437 nouveau_svm_fault_cache(struct nouveau_svm *svm,
 438                         struct nouveau_svm_fault_buffer *buffer, u32 offset)
 439 {
 440         struct nvif_object *memory = &buffer->object;
 441         const u32 instlo = nvif_rd32(memory, offset + 0x00);
 442         const u32 insthi = nvif_rd32(memory, offset + 0x04);
 443         const u32 addrlo = nvif_rd32(memory, offset + 0x08);
 444         const u32 addrhi = nvif_rd32(memory, offset + 0x0c);
 445         const u32 timelo = nvif_rd32(memory, offset + 0x10);
 446         const u32 timehi = nvif_rd32(memory, offset + 0x14);
 447         const u32 engine = nvif_rd32(memory, offset + 0x18);
 448         const u32   info = nvif_rd32(memory, offset + 0x1c);
 449         const u64   inst = (u64)insthi << 32 | instlo;
 450         const u8     gpc = (info & 0x1f000000) >> 24;
 451         const u8     hub = (info & 0x00100000) >> 20;
 452         const u8  client = (info & 0x00007f00) >> 8;
 453         struct nouveau_svm_fault *fault;
 454
 455         //XXX: i think we're supposed to spin waiting */
 456         if (WARN_ON(!(info & 0x80000000)))
 457                 return;
 458
 459         nvif_mask(memory, offset + 0x1c, 0x80000000, 0x00000000);
 460
 461         if (!buffer->fault[buffer->fault_nr]) {
 462                 fault = kmalloc(sizeof(*fault), GFP_KERNEL);
 463                 if (WARN_ON(!fault)) {
 464                         nouveau_svm_fault_cancel(svm, inst, hub, gpc, client);
 465                         return;
 466                 }
 467                 buffer->fault[buffer->fault_nr] = fault;
 468         }
 469
 470         fault = buffer->fault[buffer->fault_nr++];
 471         fault->inst   = inst;
 472         fault->addr   = (u64)addrhi << 32 | addrlo;
 473         fault->time   = (u64)timehi << 32 | timelo;
 474         fault->engine = engine;
 475         fault->gpc    = gpc;
 476         fault->hub    = hub;
 477         fault->access = (info & 0x000f0000) >> 16;
 478         fault->client = client;
 479         fault->fault  = (info & 0x0000001f);
 480
 481         SVM_DBG(svm, "fault %016llx %016llx %02x",
 482                 fault->inst, fault->addr, fault->access);
 483 }
 484
 485 struct svm_notifier {
 486         struct mmu_interval_notifier notifier;
 487         struct nouveau_svmm *svmm;
 488 };
 489
 490 static bool nouveau_svm_range_invalidate(struct mmu_interval_notifier *mni,
 491                                          const struct mmu_notifier_range *range,
 492                                          unsigned long cur_seq)
 493 {
 494         struct svm_notifier *sn =
 495                 container_of(mni, struct svm_notifier, notifier);
 496
 497         /*
 498          * serializes the update to mni->invalidate_seq done by caller and
 499          * prevents invalidation of the PTE from progressing while HW is being
 500          * programmed. This is very hacky and only works because the normal
 501          * notifier that does invalidation is always called after the range
 502          * notifier.
 503          */
 504         if (mmu_notifier_range_blockable(range))
 505                 mutex_lock(&sn->svmm->mutex);
 506         else if (!mutex_trylock(&sn->svmm->mutex))
 507                 return false;
 508         mmu_interval_set_seq(mni, cur_seq);
 509         mutex_unlock(&sn->svmm->mutex);
 510         return true;
 511 }
 512
 513 static const struct mmu_interval_notifier_ops nouveau_svm_mni_ops = {
 514         .invalidate = nouveau_svm_range_invalidate,
 515 };
 516
 517 static int nouveau_range_fault(struct nouveau_svmm *svmm,
 518                                struct nouveau_drm *drm, void *data, u32 size,
 519                                u64 *pfns, struct svm_notifier *notifier)
 520 {
 521         unsigned long timeout =
 522                 jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
 523         /* Have HMM fault pages within the fault window to the GPU. */
 524         struct hmm_range range = {
 525                 .notifier = &notifier->notifier,
 526                 .start = notifier->notifier.interval_tree.start,
 527                 .end = notifier->notifier.interval_tree.last + 1,
 528                 .pfns = pfns,
 529                 .flags = nouveau_svm_pfn_flags,
 530                 .values = nouveau_svm_pfn_values,
 531                 .pfn_shift = NVIF_VMM_PFNMAP_V0_ADDR_SHIFT,
 532         };
 533         struct mm_struct *mm = notifier->notifier.mm;
 534         long ret;
 535
 536         while (true) {
 537                 if (time_after(jiffies, timeout))
 538                         return -EBUSY;
 539
 540                 range.notifier_seq = mmu_interval_read_begin(range.notifier);
 541                 range.default_flags = 0;
 542                 range.pfn_flags_mask = -1UL;
 543                 down_read(&mm->mmap_sem);
 544                 ret = hmm_range_fault(&range, 0);
 545                 up_read(&mm->mmap_sem);
 546                 if (ret <= 0) {
 547                         if (ret == 0 || ret == -EBUSY)
 548                                 continue;
 549                         return ret;
 550                 }
 551
 552                 mutex_lock(&svmm->mutex);
 553                 if (mmu_interval_read_retry(range.notifier,
 554                                             range.notifier_seq)) {
 555                         mutex_unlock(&svmm->mutex);
 556                         continue;
 557                 }
 558                 break;
 559         }
 560
 561         nouveau_dmem_convert_pfn(drm, &range);
 562
 563         svmm->vmm->vmm.object.client->super = true;
 564         ret = nvif_object_ioctl(&svmm->vmm->vmm.object, data, size, NULL);
 565         svmm->vmm->vmm.object.client->super = false;
 566         mutex_unlock(&svmm->mutex);
 567
 568         return ret;
 569 }
 570
 571 static int
 572 nouveau_svm_fault(struct nvif_notify *notify)
 573 {
 574         struct nouveau_svm_fault_buffer *buffer =
 575                 container_of(notify, typeof(*buffer), notify);
 576         struct nouveau_svm *svm =
 577                 container_of(buffer, typeof(*svm), buffer[buffer->id]);
 578         struct nvif_object *device = &svm->drm->client.device.object;
 579         struct nouveau_svmm *svmm;
 580         struct {
 581                 struct {
 582                         struct nvif_ioctl_v0 i;
 583                         struct nvif_ioctl_mthd_v0 m;
 584                         struct nvif_vmm_pfnmap_v0 p;
 585                 } i;
 586                 u64 phys[16];
 587         } args;
 588         struct vm_area_struct *vma;
 589         u64 inst, start, limit;
 590         int fi, fn, pi, fill;
 591         int replay = 0, ret;
 592
 593         /* Parse available fault buffer entries into a cache, and update
 594          * the GET pointer so HW can reuse the entries.
 595          */
 596         SVM_DBG(svm, "fault handler");
 597         if (buffer->get == buffer->put) {
 598                 buffer->put = nvif_rd32(device, buffer->putaddr);
 599                 buffer->get = nvif_rd32(device, buffer->getaddr);
 600                 if (buffer->get == buffer->put)
 601                         return NVIF_NOTIFY_KEEP;
 602         }
 603         buffer->fault_nr = 0;
 604
 605         SVM_DBG(svm, "get %08x put %08x", buffer->get, buffer->put);
 606         while (buffer->get != buffer->put) {
 607                 nouveau_svm_fault_cache(svm, buffer, buffer->get * 0x20);
 608                 if (++buffer->get == buffer->entries)
 609                         buffer->get = 0;
 610         }
 611         nvif_wr32(device, buffer->getaddr, buffer->get);
 612         SVM_DBG(svm, "%d fault(s) pending", buffer->fault_nr);
 613
 614         /* Sort parsed faults by instance pointer to prevent unnecessary
 615          * instance to SVMM translations, followed by address and access
 616          * type to reduce the amount of work when handling the faults.
 617          */
 618         sort(buffer->fault, buffer->fault_nr, sizeof(*buffer->fault),
 619              nouveau_svm_fault_cmp, NULL);
 620
 621         /* Lookup SVMM structure for each unique instance pointer. */
 622         mutex_lock(&svm->mutex);
 623         for (fi = 0, svmm = NULL; fi < buffer->fault_nr; fi++) {
 624                 if (!svmm || buffer->fault[fi]->inst != inst) {
 625                         struct nouveau_ivmm *ivmm =
 626                                 nouveau_ivmm_find(svm, buffer->fault[fi]->inst);
 627                         svmm = ivmm ? ivmm->svmm : NULL;
 628                         inst = buffer->fault[fi]->inst;
 629                         SVM_DBG(svm, "inst %016llx -> svm-%p", inst, svmm);
 630                 }
 631                 buffer->fault[fi]->svmm = svmm;
 632         }
 633         mutex_unlock(&svm->mutex);
 634
 635         /* Process list of faults. */
 636         args.i.i.version = 0;
 637         args.i.i.type = NVIF_IOCTL_V0_MTHD;
 638         args.i.m.version = 0;
 639         args.i.m.method = NVIF_VMM_V0_PFNMAP;
 640         args.i.p.version = 0;
 641
 642         for (fi = 0; fn = fi + 1, fi < buffer->fault_nr; fi = fn) {
 643                 struct svm_notifier notifier;
 644                 struct mm_struct *mm;
 645
 646                 /* Cancel any faults from non-SVM channels. */
 647                 if (!(svmm = buffer->fault[fi]->svmm)) {
 648                         nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
 649                         continue;
 650                 }
 651                 SVMM_DBG(svmm, "addr %016llx", buffer->fault[fi]->addr);
 652
 653                 /* We try and group handling of faults within a small
 654                  * window into a single update.
 655                  */
 656                 start = buffer->fault[fi]->addr;
 657                 limit = start + (ARRAY_SIZE(args.phys) << PAGE_SHIFT);
 658                 if (start < svmm->unmanaged.limit)
 659                         limit = min_t(u64, limit, svmm->unmanaged.start);
 660                 else
 661                 if (limit > svmm->unmanaged.start)
 662                         start = max_t(u64, start, svmm->unmanaged.limit);
 663                 SVMM_DBG(svmm, "wndw %016llx-%016llx", start, limit);
 664
 665                 mm = svmm->notifier.mm;
 666                 if (!mmget_not_zero(mm)) {
 667                         nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
 668                         continue;
 669                 }
 670
 671                 /* Intersect fault window with the CPU VMA, cancelling
 672                  * the fault if the address is invalid.
 673                  */
 674                 down_read(&mm->mmap_sem);
 675                 vma = find_vma_intersection(mm, start, limit);
 676                 if (!vma) {
 677                         SVMM_ERR(svmm, "wndw %016llx-%016llx", start, limit);
 678                         up_read(&mm->mmap_sem);
 679                         mmput(mm);
 680                         nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
 681                         continue;
 682                 }
 683                 start = max_t(u64, start, vma->vm_start);
 684                 limit = min_t(u64, limit, vma->vm_end);
 685                 up_read(&mm->mmap_sem);
 686                 SVMM_DBG(svmm, "wndw %016llx-%016llx", start, limit);
 687
 688                 if (buffer->fault[fi]->addr != start) {
 689                         SVMM_ERR(svmm, "addr %016llx", buffer->fault[fi]->addr);
 690                         mmput(mm);
 691                         nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
 692                         continue;
 693                 }
 694
 695                 /* Prepare the GPU-side update of all pages within the
 696                  * fault window, determining required pages and access
 697                  * permissions based on pending faults.
 698                  */
 699                 args.i.p.page = PAGE_SHIFT;
 700                 args.i.p.addr = start;
 701                 for (fn = fi, pi = 0;;) {
 702                         /* Determine required permissions based on GPU fault
 703                          * access flags.
 704                          *XXX: atomic?
 705                          */
 706                         if (buffer->fault[fn]->access != 0 /* READ. */ &&
 707                             buffer->fault[fn]->access != 3 /* PREFETCH. */) {
 708                                 args.phys[pi++] = NVIF_VMM_PFNMAP_V0_V |
 709                                                   NVIF_VMM_PFNMAP_V0_W;
 710                         } else {
 711                                 args.phys[pi++] = NVIF_VMM_PFNMAP_V0_V;
 712                         }
 713                         args.i.p.size = pi << PAGE_SHIFT;
 714
 715                         /* It's okay to skip over duplicate addresses from the
 716                          * same SVMM as faults are ordered by access type such
 717                          * that only the first one needs to be handled.
 718                          *
 719                          * ie. WRITE faults appear first, thus any handling of
 720                          * pending READ faults will already be satisfied.
 721                          */
 722                         while (++fn < buffer->fault_nr &&
 723                                buffer->fault[fn]->svmm == svmm &&
 724                                buffer->fault[fn    ]->addr ==
 725                                buffer->fault[fn - 1]->addr);
 726
 727                         /* If the next fault is outside the window, or all GPU
 728                          * faults have been dealt with, we're done here.
 729                          */
 730                         if (fn >= buffer->fault_nr ||
 731                             buffer->fault[fn]->svmm != svmm ||
 732                             buffer->fault[fn]->addr >= limit)
 733                                 break;
 734
 735                         /* Fill in the gap between this fault and the next. */
 736                         fill = (buffer->fault[fn    ]->addr -
 737                                 buffer->fault[fn - 1]->addr) >> PAGE_SHIFT;
 738                         while (--fill)
 739                                 args.phys[pi++] = NVIF_VMM_PFNMAP_V0_NONE;
 740                 }
 741
 742                 SVMM_DBG(svmm, "wndw %016llx-%016llx covering %d fault(s)",
 743                          args.i.p.addr,
 744                          args.i.p.addr + args.i.p.size, fn - fi);
 745
 746                 notifier.svmm = svmm;
 747                 ret = mmu_interval_notifier_insert(&notifier.notifier,
 748                                                    svmm->notifier.mm,
 749                                                    args.i.p.addr, args.i.p.size,
 750                                                    &nouveau_svm_mni_ops);
 751                 if (!ret) {
 752                         ret = nouveau_range_fault(
 753                                 svmm, svm->drm, &args,
 754                                 sizeof(args.i) + pi * sizeof(args.phys[0]),
 755                                 args.phys, &notifier);
 756                         mmu_interval_notifier_remove(&notifier.notifier);
 757                 }
 758                 mmput(mm);
 759
 760                 /* Cancel any faults in the window whose pages didn't manage
 761                  * to keep their valid bit, or stay writeable when required.
 762                  *
 763                  * If handling failed completely, cancel all faults.
 764                  */
 765                 while (fi < fn) {
 766                         struct nouveau_svm_fault *fault = buffer->fault[fi++];
 767                         pi = (fault->addr - args.i.p.addr) >> PAGE_SHIFT;
 768                         if (ret ||
 769                              !(args.phys[pi] & NVIF_VMM_PFNMAP_V0_V) ||
 770                             (!(args.phys[pi] & NVIF_VMM_PFNMAP_V0_W) &&
 771                              fault->access != 0 && fault->access != 3)) {
 772                                 nouveau_svm_fault_cancel_fault(svm, fault);
 773                                 continue;
 774                         }
 775                         replay++;
 776                 }
 777         }
 778
 779         /* Issue fault replay to the GPU. */
 780         if (replay)
 781                 nouveau_svm_fault_replay(svm);
 782         return NVIF_NOTIFY_KEEP;
 783 }
 784
 785 static void
 786 nouveau_svm_fault_buffer_fini(struct nouveau_svm *svm, int id)
 787 {
 788         struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
 789         nvif_notify_put(&buffer->notify);
 790 }
 791
 792 static int
 793 nouveau_svm_fault_buffer_init(struct nouveau_svm *svm, int id)
 794 {
 795         struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
 796         struct nvif_object *device = &svm->drm->client.device.object;
 797         buffer->get = nvif_rd32(device, buffer->getaddr);
 798         buffer->put = nvif_rd32(device, buffer->putaddr);
 799         SVM_DBG(svm, "get %08x put %08x (init)", buffer->get, buffer->put);
 800         return nvif_notify_get(&buffer->notify);
 801 }
 802
 803 static void
 804 nouveau_svm_fault_buffer_dtor(struct nouveau_svm *svm, int id)
 805 {
 806         struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
 807         int i;
 808
 809         if (buffer->fault) {
 810                 for (i = 0; buffer->fault[i] && i < buffer->entries; i++)
 811                         kfree(buffer->fault[i]);
 812                 kvfree(buffer->fault);
 813         }
 814
 815         nouveau_svm_fault_buffer_fini(svm, id);
 816
 817         nvif_notify_fini(&buffer->notify);
 818         nvif_object_fini(&buffer->object);
 819 }
 820
 821 static int
 822 nouveau_svm_fault_buffer_ctor(struct nouveau_svm *svm, s32 oclass, int id)
 823 {
 824         struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
 825         struct nouveau_drm *drm = svm->drm;
 826         struct nvif_object *device = &drm->client.device.object;
 827         struct nvif_clb069_v0 args = {};
 828         int ret;
 829
 830         buffer->id = id;
 831
 832         ret = nvif_object_init(device, 0, oclass, &args, sizeof(args),
 833                                &buffer->object);
 834         if (ret < 0) {
 835                 SVM_ERR(svm, "Fault buffer allocation failed: %d", ret);
 836                 return ret;
 837         }
 838
 839         nvif_object_map(&buffer->object, NULL, 0);
 840         buffer->entries = args.entries;
 841         buffer->getaddr = args.get;
 842         buffer->putaddr = args.put;
 843
 844         ret = nvif_notify_init(&buffer->object, nouveau_svm_fault, true,
 845                                NVB069_V0_NTFY_FAULT, NULL, 0, 0,
 846                                &buffer->notify);
 847         if (ret)
 848                 return ret;
 849
 850         buffer->fault = kvzalloc(sizeof(*buffer->fault) * buffer->entries, GFP_KERNEL);
 851         if (!buffer->fault)
 852                 return -ENOMEM;
 853
 854         return nouveau_svm_fault_buffer_init(svm, id);
 855 }
 856
 857 void
 858 nouveau_svm_resume(struct nouveau_drm *drm)
 859 {
 860         struct nouveau_svm *svm = drm->svm;
 861         if (svm)
 862                 nouveau_svm_fault_buffer_init(svm, 0);
 863 }
 864
 865 void
 866 nouveau_svm_suspend(struct nouveau_drm *drm)
 867 {
 868         struct nouveau_svm *svm = drm->svm;
 869         if (svm)
 870                 nouveau_svm_fault_buffer_fini(svm, 0);
 871 }
 872
 873 void
 874 nouveau_svm_fini(struct nouveau_drm *drm)
 875 {
 876         struct nouveau_svm *svm = drm->svm;
 877         if (svm) {
 878                 nouveau_svm_fault_buffer_dtor(svm, 0);
 879                 kfree(drm->svm);
 880                 drm->svm = NULL;
 881         }
 882 }
 883
 884 void
 885 nouveau_svm_init(struct nouveau_drm *drm)
 886 {
 887         static const struct nvif_mclass buffers[] = {
 888                 {   VOLTA_FAULT_BUFFER_A, 0 },
 889                 { MAXWELL_FAULT_BUFFER_A, 0 },
 890                 {}
 891         };
 892         struct nouveau_svm *svm;
 893         int ret;
 894
 895         /* Disable on Volta and newer until channel recovery is fixed,
 896          * otherwise clients will have a trivial way to trash the GPU
 897          * for everyone.
 898          */
 899         if (drm->client.device.info.family > NV_DEVICE_INFO_V0_PASCAL)
 900                 return;
 901
 902         if (!(drm->svm = svm = kzalloc(sizeof(*drm->svm), GFP_KERNEL)))
 903                 return;
 904
 905         drm->svm->drm = drm;
 906         mutex_init(&drm->svm->mutex);
 907         INIT_LIST_HEAD(&drm->svm->inst);
 908
 909         ret = nvif_mclass(&drm->client.device.object, buffers);
 910         if (ret < 0) {
 911                 SVM_DBG(svm, "No supported fault buffer class");
 912                 nouveau_svm_fini(drm);
 913                 return;
 914         }
 915
 916         ret = nouveau_svm_fault_buffer_ctor(svm, buffers[ret].oclass, 0);
 917         if (ret) {
 918                 nouveau_svm_fini(drm);
 919                 return;
 920         }
 921
 922         SVM_DBG(svm, "Initialised");
 923 }