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         if (!cli->svm.svmm) {
 175                 up_read(&mm->mmap_sem);
 176                 return -EINVAL;
 177         }
 178
 179         for (addr = args->va_start, end = args->va_start + size; addr < end;) {
 180                 struct vm_area_struct *vma;
 181                 unsigned long next;
 182
 183                 vma = find_vma_intersection(mm, addr, end);
 184                 if (!vma)
 185                         break;
 186
 187                 addr = max(addr, vma->vm_start);
 188                 next = min(vma->vm_end, end);
 189                 /* This is a best effort so we ignore errors */
 190                 nouveau_dmem_migrate_vma(cli->drm, vma, addr, next);
 191                 addr = next;
 192         }
 193
 194         /*
 195          * FIXME Return the number of page we have migrated, again we need to
 196          * update the migrate API to return that information so that we can
 197          * report it to user space.
 198          */
 199         args->result = 0;
 200
 201         up_read(&mm->mmap_sem);
 202         mmput(mm);
 203
 204         return 0;
 205 }
 206
 207 /* Unlink channel instance from SVMM. */
 208 void
 209 nouveau_svmm_part(struct nouveau_svmm *svmm, u64 inst)
 210 {
 211         struct nouveau_ivmm *ivmm;
 212         if (svmm) {
 213                 mutex_lock(&svmm->vmm->cli->drm->svm->mutex);
 214                 ivmm = nouveau_ivmm_find(svmm->vmm->cli->drm->svm, inst);
 215                 if (ivmm) {
 216                         list_del(&ivmm->head);
 217                         kfree(ivmm);
 218                 }
 219                 mutex_unlock(&svmm->vmm->cli->drm->svm->mutex);
 220         }
 221 }
 222
 223 /* Link channel instance to SVMM. */
 224 int
 225 nouveau_svmm_join(struct nouveau_svmm *svmm, u64 inst)
 226 {
 227         struct nouveau_ivmm *ivmm;
 228         if (svmm) {
 229                 if (!(ivmm = kmalloc(sizeof(*ivmm), GFP_KERNEL)))
 230                         return -ENOMEM;
 231                 ivmm->svmm = svmm;
 232                 ivmm->inst = inst;
 233
 234                 mutex_lock(&svmm->vmm->cli->drm->svm->mutex);
 235                 list_add(&ivmm->head, &svmm->vmm->cli->drm->svm->inst);
 236                 mutex_unlock(&svmm->vmm->cli->drm->svm->mutex);
 237         }
 238         return 0;
 239 }
 240
 241 /* Invalidate SVMM address-range on GPU. */
 242 static void
 243 nouveau_svmm_invalidate(struct nouveau_svmm *svmm, u64 start, u64 limit)
 244 {
 245         if (limit > start) {
 246                 bool super = svmm->vmm->vmm.object.client->super;
 247                 svmm->vmm->vmm.object.client->super = true;
 248                 nvif_object_mthd(&svmm->vmm->vmm.object, NVIF_VMM_V0_PFNCLR,
 249                                  &(struct nvif_vmm_pfnclr_v0) {
 250                                         .addr = start,
 251                                         .size = limit - start,
 252                                  }, sizeof(struct nvif_vmm_pfnclr_v0));
 253                 svmm->vmm->vmm.object.client->super = super;
 254         }
 255 }
 256
 257 static int
 258 nouveau_svmm_invalidate_range_start(struct mmu_notifier *mn,
 259                                     const struct mmu_notifier_range *update)
 260 {
 261         struct nouveau_svmm *svmm =
 262                 container_of(mn, struct nouveau_svmm, notifier);
 263         unsigned long start = update->start;
 264         unsigned long limit = update->end;
 265
 266         if (!mmu_notifier_range_blockable(update))
 267                 return -EAGAIN;
 268
 269         SVMM_DBG(svmm, "invalidate %016lx-%016lx", start, limit);
 270
 271         mutex_lock(&svmm->mutex);
 272         if (unlikely(!svmm->vmm))
 273                 goto out;
 274
 275         if (limit > svmm->unmanaged.start && start < svmm->unmanaged.limit) {
 276                 if (start < svmm->unmanaged.start) {
 277                         nouveau_svmm_invalidate(svmm, start,
 278                                                 svmm->unmanaged.limit);
 279                 }
 280                 start = svmm->unmanaged.limit;
 281         }
 282
 283         nouveau_svmm_invalidate(svmm, start, limit);
 284
 285 out:
 286         mutex_unlock(&svmm->mutex);
 287         return 0;
 288 }
 289
 290 static void nouveau_svmm_free_notifier(struct mmu_notifier *mn)
 291 {
 292         kfree(container_of(mn, struct nouveau_svmm, notifier));
 293 }
 294
 295 static const struct mmu_notifier_ops nouveau_mn_ops = {
 296         .invalidate_range_start = nouveau_svmm_invalidate_range_start,
 297         .free_notifier = nouveau_svmm_free_notifier,
 298 };
 299
 300 void
 301 nouveau_svmm_fini(struct nouveau_svmm **psvmm)
 302 {
 303         struct nouveau_svmm *svmm = *psvmm;
 304         if (svmm) {
 305                 mutex_lock(&svmm->mutex);
 306                 svmm->vmm = NULL;
 307                 mutex_unlock(&svmm->mutex);
 308                 mmu_notifier_put(&svmm->notifier);
 309                 *psvmm = NULL;
 310         }
 311 }
 312
 313 int
 314 nouveau_svmm_init(struct drm_device *dev, void *data,
 315                   struct drm_file *file_priv)
 316 {
 317         struct nouveau_cli *cli = nouveau_cli(file_priv);
 318         struct nouveau_svmm *svmm;
 319         struct drm_nouveau_svm_init *args = data;
 320         int ret;
 321
 322         /* Allocate tracking for SVM-enabled VMM. */
 323         if (!(svmm = kzalloc(sizeof(*svmm), GFP_KERNEL)))
 324                 return -ENOMEM;
 325         svmm->vmm = &cli->svm;
 326         svmm->unmanaged.start = args->unmanaged_addr;
 327         svmm->unmanaged.limit = args->unmanaged_addr + args->unmanaged_size;
 328         mutex_init(&svmm->mutex);
 329
 330         /* Check that SVM isn't already enabled for the client. */
 331         mutex_lock(&cli->mutex);
 332         if (cli->svm.cli) {
 333                 ret = -EBUSY;
 334                 goto out_free;
 335         }
 336
 337         /* Allocate a new GPU VMM that can support SVM (managed by the
 338          * client, with replayable faults enabled).
 339          *
 340          * All future channel/memory allocations will make use of this
 341          * VMM instead of the standard one.
 342          */
 343         ret = nvif_vmm_init(&cli->mmu, cli->vmm.vmm.object.oclass, true,
 344                             args->unmanaged_addr, args->unmanaged_size,
 345                             &(struct gp100_vmm_v0) {
 346                                 .fault_replay = true,
 347                             }, sizeof(struct gp100_vmm_v0), &cli->svm.vmm);
 348         if (ret)
 349                 goto out_free;
 350
 351         down_write(&current->mm->mmap_sem);
 352         svmm->notifier.ops = &nouveau_mn_ops;
 353         ret = __mmu_notifier_register(&svmm->notifier, current->mm);
 354         if (ret)
 355                 goto out_mm_unlock;
 356         /* Note, ownership of svmm transfers to mmu_notifier */
 357
 358         cli->svm.svmm = svmm;
 359         cli->svm.cli = cli;
 360         up_write(&current->mm->mmap_sem);
 361         mutex_unlock(&cli->mutex);
 362         return 0;
 363
 364 out_mm_unlock:
 365         up_write(&current->mm->mmap_sem);
 366 out_free:
 367         mutex_unlock(&cli->mutex);
 368         kfree(svmm);
 369         return ret;
 370 }
 371
 372 static const u64
 373 nouveau_svm_pfn_flags[HMM_PFN_FLAG_MAX] = {
 374         [HMM_PFN_VALID         ] = NVIF_VMM_PFNMAP_V0_V,
 375         [HMM_PFN_WRITE         ] = NVIF_VMM_PFNMAP_V0_W,
 376 };
 377
 378 static const u64
 379 nouveau_svm_pfn_values[HMM_PFN_VALUE_MAX] = {
 380         [HMM_PFN_ERROR  ] = ~NVIF_VMM_PFNMAP_V0_V,
 381         [HMM_PFN_NONE   ] =  NVIF_VMM_PFNMAP_V0_NONE,
 382         [HMM_PFN_SPECIAL] = ~NVIF_VMM_PFNMAP_V0_V,
 383 };
 384
 385 /* Issue fault replay for GPU to retry accesses that faulted previously. */
 386 static void
 387 nouveau_svm_fault_replay(struct nouveau_svm *svm)
 388 {
 389         SVM_DBG(svm, "replay");
 390         WARN_ON(nvif_object_mthd(&svm->drm->client.vmm.vmm.object,
 391                                  GP100_VMM_VN_FAULT_REPLAY,
 392                                  &(struct gp100_vmm_fault_replay_vn) {},
 393                                  sizeof(struct gp100_vmm_fault_replay_vn)));
 394 }
 395
 396 /* Cancel a replayable fault that could not be handled.
 397  *
 398  * Cancelling the fault will trigger recovery to reset the engine
 399  * and kill the offending channel (ie. GPU SIGSEGV).
 400  */
 401 static void
 402 nouveau_svm_fault_cancel(struct nouveau_svm *svm,
 403                          u64 inst, u8 hub, u8 gpc, u8 client)
 404 {
 405         SVM_DBG(svm, "cancel %016llx %d %02x %02x", inst, hub, gpc, client);
 406         WARN_ON(nvif_object_mthd(&svm->drm->client.vmm.vmm.object,
 407                                  GP100_VMM_VN_FAULT_CANCEL,
 408                                  &(struct gp100_vmm_fault_cancel_v0) {
 409                                         .hub = hub,
 410                                         .gpc = gpc,
 411                                         .client = client,
 412                                         .inst = inst,
 413                                  }, sizeof(struct gp100_vmm_fault_cancel_v0)));
 414 }
 415
 416 static void
 417 nouveau_svm_fault_cancel_fault(struct nouveau_svm *svm,
 418                                struct nouveau_svm_fault *fault)
 419 {
 420         nouveau_svm_fault_cancel(svm, fault->inst,
 421                                       fault->hub,
 422                                       fault->gpc,
 423                                       fault->client);
 424 }
 425
 426 static int
 427 nouveau_svm_fault_cmp(const void *a, const void *b)
 428 {
 429         const struct nouveau_svm_fault *fa = *(struct nouveau_svm_fault **)a;
 430         const struct nouveau_svm_fault *fb = *(struct nouveau_svm_fault **)b;
 431         int ret;
 432         if ((ret = (s64)fa->inst - fb->inst))
 433                 return ret;
 434         if ((ret = (s64)fa->addr - fb->addr))
 435                 return ret;
 436         /*XXX: atomic? */
 437         return (fa->access == 0 || fa->access == 3) -
 438                (fb->access == 0 || fb->access == 3);
 439 }
 440
 441 static void
 442 nouveau_svm_fault_cache(struct nouveau_svm *svm,
 443                         struct nouveau_svm_fault_buffer *buffer, u32 offset)
 444 {
 445         struct nvif_object *memory = &buffer->object;
 446         const u32 instlo = nvif_rd32(memory, offset + 0x00);
 447         const u32 insthi = nvif_rd32(memory, offset + 0x04);
 448         const u32 addrlo = nvif_rd32(memory, offset + 0x08);
 449         const u32 addrhi = nvif_rd32(memory, offset + 0x0c);
 450         const u32 timelo = nvif_rd32(memory, offset + 0x10);
 451         const u32 timehi = nvif_rd32(memory, offset + 0x14);
 452         const u32 engine = nvif_rd32(memory, offset + 0x18);
 453         const u32   info = nvif_rd32(memory, offset + 0x1c);
 454         const u64   inst = (u64)insthi << 32 | instlo;
 455         const u8     gpc = (info & 0x1f000000) >> 24;
 456         const u8     hub = (info & 0x00100000) >> 20;
 457         const u8  client = (info & 0x00007f00) >> 8;
 458         struct nouveau_svm_fault *fault;
 459
 460         //XXX: i think we're supposed to spin waiting */
 461         if (WARN_ON(!(info & 0x80000000)))
 462                 return;
 463
 464         nvif_mask(memory, offset + 0x1c, 0x80000000, 0x00000000);
 465
 466         if (!buffer->fault[buffer->fault_nr]) {
 467                 fault = kmalloc(sizeof(*fault), GFP_KERNEL);
 468                 if (WARN_ON(!fault)) {
 469                         nouveau_svm_fault_cancel(svm, inst, hub, gpc, client);
 470                         return;
 471                 }
 472                 buffer->fault[buffer->fault_nr] = fault;
 473         }
 474
 475         fault = buffer->fault[buffer->fault_nr++];
 476         fault->inst   = inst;
 477         fault->addr   = (u64)addrhi << 32 | addrlo;
 478         fault->time   = (u64)timehi << 32 | timelo;
 479         fault->engine = engine;
 480         fault->gpc    = gpc;
 481         fault->hub    = hub;
 482         fault->access = (info & 0x000f0000) >> 16;
 483         fault->client = client;
 484         fault->fault  = (info & 0x0000001f);
 485
 486         SVM_DBG(svm, "fault %016llx %016llx %02x",
 487                 fault->inst, fault->addr, fault->access);
 488 }
 489
 490 struct svm_notifier {
 491         struct mmu_interval_notifier notifier;
 492         struct nouveau_svmm *svmm;
 493 };
 494
 495 static bool nouveau_svm_range_invalidate(struct mmu_interval_notifier *mni,
 496                                          const struct mmu_notifier_range *range,
 497                                          unsigned long cur_seq)
 498 {
 499         struct svm_notifier *sn =
 500                 container_of(mni, struct svm_notifier, notifier);
 501
 502         /*
 503          * serializes the update to mni->invalidate_seq done by caller and
 504          * prevents invalidation of the PTE from progressing while HW is being
 505          * programmed. This is very hacky and only works because the normal
 506          * notifier that does invalidation is always called after the range
 507          * notifier.
 508          */
 509         if (mmu_notifier_range_blockable(range))
 510                 mutex_lock(&sn->svmm->mutex);
 511         else if (!mutex_trylock(&sn->svmm->mutex))
 512                 return false;
 513         mmu_interval_set_seq(mni, cur_seq);
 514         mutex_unlock(&sn->svmm->mutex);
 515         return true;
 516 }
 517
 518 static const struct mmu_interval_notifier_ops nouveau_svm_mni_ops = {
 519         .invalidate = nouveau_svm_range_invalidate,
 520 };
 521
 522 static int nouveau_range_fault(struct nouveau_svmm *svmm,
 523                                struct nouveau_drm *drm, void *data, u32 size,
 524                                u64 *pfns, struct svm_notifier *notifier)
 525 {
 526         unsigned long timeout =
 527                 jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
 528         /* Have HMM fault pages within the fault window to the GPU. */
 529         struct hmm_range range = {
 530                 .notifier = &notifier->notifier,
 531                 .start = notifier->notifier.interval_tree.start,
 532                 .end = notifier->notifier.interval_tree.last + 1,
 533                 .pfns = pfns,
 534                 .flags = nouveau_svm_pfn_flags,
 535                 .values = nouveau_svm_pfn_values,
 536                 .pfn_shift = NVIF_VMM_PFNMAP_V0_ADDR_SHIFT,
 537         };
 538         struct mm_struct *mm = notifier->notifier.mm;
 539         long ret;
 540
 541         while (true) {
 542                 if (time_after(jiffies, timeout))
 543                         return -EBUSY;
 544
 545                 range.notifier_seq = mmu_interval_read_begin(range.notifier);
 546                 range.default_flags = 0;
 547                 range.pfn_flags_mask = -1UL;
 548                 down_read(&mm->mmap_sem);
 549                 ret = hmm_range_fault(&range);
 550                 up_read(&mm->mmap_sem);
 551                 if (ret <= 0) {
 552                         if (ret == 0 || ret == -EBUSY)
 553                                 continue;
 554                         return ret;
 555                 }
 556
 557                 mutex_lock(&svmm->mutex);
 558                 if (mmu_interval_read_retry(range.notifier,
 559                                             range.notifier_seq)) {
 560                         mutex_unlock(&svmm->mutex);
 561                         continue;
 562                 }
 563                 break;
 564         }
 565
 566         nouveau_dmem_convert_pfn(drm, &range);
 567
 568         svmm->vmm->vmm.object.client->super = true;
 569         ret = nvif_object_ioctl(&svmm->vmm->vmm.object, data, size, NULL);
 570         svmm->vmm->vmm.object.client->super = false;
 571         mutex_unlock(&svmm->mutex);
 572
 573         return ret;
 574 }
 575
 576 static int
 577 nouveau_svm_fault(struct nvif_notify *notify)
 578 {
 579         struct nouveau_svm_fault_buffer *buffer =
 580                 container_of(notify, typeof(*buffer), notify);
 581         struct nouveau_svm *svm =
 582                 container_of(buffer, typeof(*svm), buffer[buffer->id]);
 583         struct nvif_object *device = &svm->drm->client.device.object;
 584         struct nouveau_svmm *svmm;
 585         struct {
 586                 struct {
 587                         struct nvif_ioctl_v0 i;
 588                         struct nvif_ioctl_mthd_v0 m;
 589                         struct nvif_vmm_pfnmap_v0 p;
 590                 } i;
 591                 u64 phys[16];
 592         } args;
 593         struct vm_area_struct *vma;
 594         u64 inst, start, limit;
 595         int fi, fn, pi, fill;
 596         int replay = 0, ret;
 597
 598         /* Parse available fault buffer entries into a cache, and update
 599          * the GET pointer so HW can reuse the entries.
 600          */
 601         SVM_DBG(svm, "fault handler");
 602         if (buffer->get == buffer->put) {
 603                 buffer->put = nvif_rd32(device, buffer->putaddr);
 604                 buffer->get = nvif_rd32(device, buffer->getaddr);
 605                 if (buffer->get == buffer->put)
 606                         return NVIF_NOTIFY_KEEP;
 607         }
 608         buffer->fault_nr = 0;
 609
 610         SVM_DBG(svm, "get %08x put %08x", buffer->get, buffer->put);
 611         while (buffer->get != buffer->put) {
 612                 nouveau_svm_fault_cache(svm, buffer, buffer->get * 0x20);
 613                 if (++buffer->get == buffer->entries)
 614                         buffer->get = 0;
 615         }
 616         nvif_wr32(device, buffer->getaddr, buffer->get);
 617         SVM_DBG(svm, "%d fault(s) pending", buffer->fault_nr);
 618
 619         /* Sort parsed faults by instance pointer to prevent unnecessary
 620          * instance to SVMM translations, followed by address and access
 621          * type to reduce the amount of work when handling the faults.
 622          */
 623         sort(buffer->fault, buffer->fault_nr, sizeof(*buffer->fault),
 624              nouveau_svm_fault_cmp, NULL);
 625
 626         /* Lookup SVMM structure for each unique instance pointer. */
 627         mutex_lock(&svm->mutex);
 628         for (fi = 0, svmm = NULL; fi < buffer->fault_nr; fi++) {
 629                 if (!svmm || buffer->fault[fi]->inst != inst) {
 630                         struct nouveau_ivmm *ivmm =
 631                                 nouveau_ivmm_find(svm, buffer->fault[fi]->inst);
 632                         svmm = ivmm ? ivmm->svmm : NULL;
 633                         inst = buffer->fault[fi]->inst;
 634                         SVM_DBG(svm, "inst %016llx -> svm-%p", inst, svmm);
 635                 }
 636                 buffer->fault[fi]->svmm = svmm;
 637         }
 638         mutex_unlock(&svm->mutex);
 639
 640         /* Process list of faults. */
 641         args.i.i.version = 0;
 642         args.i.i.type = NVIF_IOCTL_V0_MTHD;
 643         args.i.m.version = 0;
 644         args.i.m.method = NVIF_VMM_V0_PFNMAP;
 645         args.i.p.version = 0;
 646
 647         for (fi = 0; fn = fi + 1, fi < buffer->fault_nr; fi = fn) {
 648                 struct svm_notifier notifier;
 649                 struct mm_struct *mm;
 650
 651                 /* Cancel any faults from non-SVM channels. */
 652                 if (!(svmm = buffer->fault[fi]->svmm)) {
 653                         nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
 654                         continue;
 655                 }
 656                 SVMM_DBG(svmm, "addr %016llx", buffer->fault[fi]->addr);
 657
 658                 /* We try and group handling of faults within a small
 659                  * window into a single update.
 660                  */
 661                 start = buffer->fault[fi]->addr;
 662                 limit = start + (ARRAY_SIZE(args.phys) << PAGE_SHIFT);
 663                 if (start < svmm->unmanaged.limit)
 664                         limit = min_t(u64, limit, svmm->unmanaged.start);
 665                 SVMM_DBG(svmm, "wndw %016llx-%016llx", start, limit);
 666
 667                 mm = svmm->notifier.mm;
 668                 if (!mmget_not_zero(mm)) {
 669                         nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
 670                         continue;
 671                 }
 672
 673                 /* Intersect fault window with the CPU VMA, cancelling
 674                  * the fault if the address is invalid.
 675                  */
 676                 down_read(&mm->mmap_sem);
 677                 vma = find_vma_intersection(mm, start, limit);
 678                 if (!vma) {
 679                         SVMM_ERR(svmm, "wndw %016llx-%016llx", start, limit);
 680                         up_read(&mm->mmap_sem);
 681                         mmput(mm);
 682                         nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
 683                         continue;
 684                 }
 685                 start = max_t(u64, start, vma->vm_start);
 686                 limit = min_t(u64, limit, vma->vm_end);
 687                 up_read(&mm->mmap_sem);
 688                 SVMM_DBG(svmm, "wndw %016llx-%016llx", start, limit);
 689
 690                 if (buffer->fault[fi]->addr != start) {
 691                         SVMM_ERR(svmm, "addr %016llx", buffer->fault[fi]->addr);
 692                         mmput(mm);
 693                         nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
 694                         continue;
 695                 }
 696
 697                 /* Prepare the GPU-side update of all pages within the
 698                  * fault window, determining required pages and access
 699                  * permissions based on pending faults.
 700                  */
 701                 args.i.p.page = PAGE_SHIFT;
 702                 args.i.p.addr = start;
 703                 for (fn = fi, pi = 0;;) {
 704                         /* Determine required permissions based on GPU fault
 705                          * access flags.
 706                          *XXX: atomic?
 707                          */
 708                         if (buffer->fault[fn]->access != 0 /* READ. */ &&
 709                             buffer->fault[fn]->access != 3 /* PREFETCH. */) {
 710                                 args.phys[pi++] = NVIF_VMM_PFNMAP_V0_V |
 711                                                   NVIF_VMM_PFNMAP_V0_W;
 712                         } else {
 713                                 args.phys[pi++] = NVIF_VMM_PFNMAP_V0_V;
 714                         }
 715                         args.i.p.size = pi << PAGE_SHIFT;
 716
 717                         /* It's okay to skip over duplicate addresses from the
 718                          * same SVMM as faults are ordered by access type such
 719                          * that only the first one needs to be handled.
 720                          *
 721                          * ie. WRITE faults appear first, thus any handling of
 722                          * pending READ faults will already be satisfied.
 723                          */
 724                         while (++fn < buffer->fault_nr &&
 725                                buffer->fault[fn]->svmm == svmm &&
 726                                buffer->fault[fn    ]->addr ==
 727                                buffer->fault[fn - 1]->addr);
 728
 729                         /* If the next fault is outside the window, or all GPU
 730                          * faults have been dealt with, we're done here.
 731                          */
 732                         if (fn >= buffer->fault_nr ||
 733                             buffer->fault[fn]->svmm != svmm ||
 734                             buffer->fault[fn]->addr >= limit)
 735                                 break;
 736
 737                         /* Fill in the gap between this fault and the next. */
 738                         fill = (buffer->fault[fn    ]->addr -
 739                                 buffer->fault[fn - 1]->addr) >> PAGE_SHIFT;
 740                         while (--fill)
 741                                 args.phys[pi++] = NVIF_VMM_PFNMAP_V0_NONE;
 742                 }
 743
 744                 SVMM_DBG(svmm, "wndw %016llx-%016llx covering %d fault(s)",
 745                          args.i.p.addr,
 746                          args.i.p.addr + args.i.p.size, fn - fi);
 747
 748                 notifier.svmm = svmm;
 749                 ret = mmu_interval_notifier_insert(&notifier.notifier,
 750                                                    svmm->notifier.mm,
 751                                                    args.i.p.addr, args.i.p.size,
 752                                                    &nouveau_svm_mni_ops);
 753                 if (!ret) {
 754                         ret = nouveau_range_fault(
 755                                 svmm, svm->drm, &args,
 756                                 sizeof(args.i) + pi * sizeof(args.phys[0]),
 757                                 args.phys, &notifier);
 758                         mmu_interval_notifier_remove(&notifier.notifier);
 759                 }
 760                 mmput(mm);
 761
 762                 /* Cancel any faults in the window whose pages didn't manage
 763                  * to keep their valid bit, or stay writeable when required.
 764                  *
 765                  * If handling failed completely, cancel all faults.
 766                  */
 767                 while (fi < fn) {
 768                         struct nouveau_svm_fault *fault = buffer->fault[fi++];
 769                         pi = (fault->addr - args.i.p.addr) >> PAGE_SHIFT;
 770                         if (ret ||
 771                              !(args.phys[pi] & NVIF_VMM_PFNMAP_V0_V) ||
 772                             (!(args.phys[pi] & NVIF_VMM_PFNMAP_V0_W) &&
 773                              fault->access != 0 && fault->access != 3)) {
 774                                 nouveau_svm_fault_cancel_fault(svm, fault);
 775                                 continue;
 776                         }
 777                         replay++;
 778                 }
 779         }
 780
 781         /* Issue fault replay to the GPU. */
 782         if (replay)
 783                 nouveau_svm_fault_replay(svm);
 784         return NVIF_NOTIFY_KEEP;
 785 }
 786
 787 static void
 788 nouveau_svm_fault_buffer_fini(struct nouveau_svm *svm, int id)
 789 {
 790         struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
 791         nvif_notify_put(&buffer->notify);
 792 }
 793
 794 static int
 795 nouveau_svm_fault_buffer_init(struct nouveau_svm *svm, int id)
 796 {
 797         struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
 798         struct nvif_object *device = &svm->drm->client.device.object;
 799         buffer->get = nvif_rd32(device, buffer->getaddr);
 800         buffer->put = nvif_rd32(device, buffer->putaddr);
 801         SVM_DBG(svm, "get %08x put %08x (init)", buffer->get, buffer->put);
 802         return nvif_notify_get(&buffer->notify);
 803 }
 804
 805 static void
 806 nouveau_svm_fault_buffer_dtor(struct nouveau_svm *svm, int id)
 807 {
 808         struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
 809         int i;
 810
 811         if (buffer->fault) {
 812                 for (i = 0; buffer->fault[i] && i < buffer->entries; i++)
 813                         kfree(buffer->fault[i]);
 814                 kvfree(buffer->fault);
 815         }
 816
 817         nouveau_svm_fault_buffer_fini(svm, id);
 818
 819         nvif_notify_fini(&buffer->notify);
 820         nvif_object_fini(&buffer->object);
 821 }
 822
 823 static int
 824 nouveau_svm_fault_buffer_ctor(struct nouveau_svm *svm, s32 oclass, int id)
 825 {
 826         struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
 827         struct nouveau_drm *drm = svm->drm;
 828         struct nvif_object *device = &drm->client.device.object;
 829         struct nvif_clb069_v0 args = {};
 830         int ret;
 831
 832         buffer->id = id;
 833
 834         ret = nvif_object_init(device, 0, oclass, &args, sizeof(args),
 835                                &buffer->object);
 836         if (ret < 0) {
 837                 SVM_ERR(svm, "Fault buffer allocation failed: %d", ret);
 838                 return ret;
 839         }
 840
 841         nvif_object_map(&buffer->object, NULL, 0);
 842         buffer->entries = args.entries;
 843         buffer->getaddr = args.get;
 844         buffer->putaddr = args.put;
 845
 846         ret = nvif_notify_init(&buffer->object, nouveau_svm_fault, true,
 847                                NVB069_V0_NTFY_FAULT, NULL, 0, 0,
 848                                &buffer->notify);
 849         if (ret)
 850                 return ret;
 851
 852         buffer->fault = kvzalloc(sizeof(*buffer->fault) * buffer->entries, GFP_KERNEL);
 853         if (!buffer->fault)
 854                 return -ENOMEM;
 855
 856         return nouveau_svm_fault_buffer_init(svm, id);
 857 }
 858
 859 void
 860 nouveau_svm_resume(struct nouveau_drm *drm)
 861 {
 862         struct nouveau_svm *svm = drm->svm;
 863         if (svm)
 864                 nouveau_svm_fault_buffer_init(svm, 0);
 865 }
 866
 867 void
 868 nouveau_svm_suspend(struct nouveau_drm *drm)
 869 {
 870         struct nouveau_svm *svm = drm->svm;
 871         if (svm)
 872                 nouveau_svm_fault_buffer_fini(svm, 0);
 873 }
 874
 875 void
 876 nouveau_svm_fini(struct nouveau_drm *drm)
 877 {
 878         struct nouveau_svm *svm = drm->svm;
 879         if (svm) {
 880                 nouveau_svm_fault_buffer_dtor(svm, 0);
 881                 kfree(drm->svm);
 882                 drm->svm = NULL;
 883         }
 884 }
 885
 886 void
 887 nouveau_svm_init(struct nouveau_drm *drm)
 888 {
 889         static const struct nvif_mclass buffers[] = {
 890                 {   VOLTA_FAULT_BUFFER_A, 0 },
 891                 { MAXWELL_FAULT_BUFFER_A, 0 },
 892                 {}
 893         };
 894         struct nouveau_svm *svm;
 895         int ret;
 896
 897         /* Disable on Volta and newer until channel recovery is fixed,
 898          * otherwise clients will have a trivial way to trash the GPU
 899          * for everyone.
 900          */
 901         if (drm->client.device.info.family > NV_DEVICE_INFO_V0_PASCAL)
 902                 return;
 903
 904         if (!(drm->svm = svm = kzalloc(sizeof(*drm->svm), GFP_KERNEL)))
 905                 return;
 906
 907         drm->svm->drm = drm;
 908         mutex_init(&drm->svm->mutex);
 909         INIT_LIST_HEAD(&drm->svm->inst);
 910
 911         ret = nvif_mclass(&drm->client.device.object, buffers);
 912         if (ret < 0) {
 913                 SVM_DBG(svm, "No supported fault buffer class");
 914                 nouveau_svm_fini(drm);
 915                 return;
 916         }
 917
 918         ret = nouveau_svm_fault_buffer_ctor(svm, buffers[ret].oclass, 0);
 919         if (ret) {
 920                 nouveau_svm_fini(drm);
 921                 return;
 922         }
 923
 924         SVM_DBG(svm, "Initialised");
 925 }