drivers/gpu/drm/i915/gt/gen8_ppgtt.c

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * Copyright © 2020 Intel Corporation
   4  */
   5
   6 #include <linux/log2.h>
   7
   8 #include "gen8_ppgtt.h"
   9 #include "i915_scatterlist.h"
  10 #include "i915_trace.h"
  11 #include "i915_pvinfo.h"
  12 #include "i915_vgpu.h"
  13 #include "intel_gt.h"
  14 #include "intel_gtt.h"
  15
  16 static u64 gen8_pde_encode(const dma_addr_t addr,
  17                            const enum i915_cache_level level)
  18 {
  19         u64 pde = addr | _PAGE_PRESENT | _PAGE_RW;
  20
  21         if (level != I915_CACHE_NONE)
  22                 pde |= PPAT_CACHED_PDE;
  23         else
  24                 pde |= PPAT_UNCACHED;
  25
  26         return pde;
  27 }
  28
  29 static u64 gen8_pte_encode(dma_addr_t addr,
  30                            enum i915_cache_level level,
  31                            u32 flags)
  32 {
  33         gen8_pte_t pte = addr | _PAGE_PRESENT | _PAGE_RW;
  34
  35         if (unlikely(flags & PTE_READ_ONLY))
  36                 pte &= ~_PAGE_RW;
  37
  38         switch (level) {
  39         case I915_CACHE_NONE:
  40                 pte |= PPAT_UNCACHED;
  41                 break;
  42         case I915_CACHE_WT:
  43                 pte |= PPAT_DISPLAY_ELLC;
  44                 break;
  45         default:
  46                 pte |= PPAT_CACHED;
  47                 break;
  48         }
  49
  50         return pte;
  51 }
  52
  53 static void gen8_ppgtt_notify_vgt(struct i915_ppgtt *ppgtt, bool create)
  54 {
  55         struct drm_i915_private *i915 = ppgtt->vm.i915;
  56         struct intel_uncore *uncore = ppgtt->vm.gt->uncore;
  57         enum vgt_g2v_type msg;
  58         int i;
  59
  60         if (create)
  61                 atomic_inc(px_used(ppgtt->pd)); /* never remove */
  62         else
  63                 atomic_dec(px_used(ppgtt->pd));
  64
  65         mutex_lock(&i915->vgpu.lock);
  66
  67         if (i915_vm_is_4lvl(&ppgtt->vm)) {
  68                 const u64 daddr = px_dma(ppgtt->pd);
  69
  70                 intel_uncore_write(uncore,
  71                                    vgtif_reg(pdp[0].lo), lower_32_bits(daddr));
  72                 intel_uncore_write(uncore,
  73                                    vgtif_reg(pdp[0].hi), upper_32_bits(daddr));
  74
  75                 msg = create ?
  76                         VGT_G2V_PPGTT_L4_PAGE_TABLE_CREATE :
  77                         VGT_G2V_PPGTT_L4_PAGE_TABLE_DESTROY;
  78         } else {
  79                 for (i = 0; i < GEN8_3LVL_PDPES; i++) {
  80                         const u64 daddr = i915_page_dir_dma_addr(ppgtt, i);
  81
  82                         intel_uncore_write(uncore,
  83                                            vgtif_reg(pdp[i].lo),
  84                                            lower_32_bits(daddr));
  85                         intel_uncore_write(uncore,
  86                                            vgtif_reg(pdp[i].hi),
  87                                            upper_32_bits(daddr));
  88                 }
  89
  90                 msg = create ?
  91                         VGT_G2V_PPGTT_L3_PAGE_TABLE_CREATE :
  92                         VGT_G2V_PPGTT_L3_PAGE_TABLE_DESTROY;
  93         }
  94
  95         /* g2v_notify atomically (via hv trap) consumes the message packet. */
  96         intel_uncore_write(uncore, vgtif_reg(g2v_notify), msg);
  97
  98         mutex_unlock(&i915->vgpu.lock);
  99 }
 100
 101 /* Index shifts into the pagetable are offset by GEN8_PTE_SHIFT [12] */
 102 #define GEN8_PAGE_SIZE (SZ_4K) /* page and page-directory sizes are the same */
 103 #define GEN8_PTE_SHIFT (ilog2(GEN8_PAGE_SIZE))
 104 #define GEN8_PDES (GEN8_PAGE_SIZE / sizeof(u64))
 105 #define gen8_pd_shift(lvl) ((lvl) * ilog2(GEN8_PDES))
 106 #define gen8_pd_index(i, lvl) i915_pde_index((i), gen8_pd_shift(lvl))
 107 #define __gen8_pte_shift(lvl) (GEN8_PTE_SHIFT + gen8_pd_shift(lvl))
 108 #define __gen8_pte_index(a, lvl) i915_pde_index((a), __gen8_pte_shift(lvl))
 109
 110 #define as_pd(x) container_of((x), typeof(struct i915_page_directory), pt)
 111
 112 static inline unsigned int
 113 gen8_pd_range(u64 start, u64 end, int lvl, unsigned int *idx)
 114 {
 115         const int shift = gen8_pd_shift(lvl);
 116         const u64 mask = ~0ull << gen8_pd_shift(lvl + 1);
 117
 118         GEM_BUG_ON(start >= end);
 119         end += ~mask >> gen8_pd_shift(1);
 120
 121         *idx = i915_pde_index(start, shift);
 122         if ((start ^ end) & mask)
 123                 return GEN8_PDES - *idx;
 124         else
 125                 return i915_pde_index(end, shift) - *idx;
 126 }
 127
 128 static inline bool gen8_pd_contains(u64 start, u64 end, int lvl)
 129 {
 130         const u64 mask = ~0ull << gen8_pd_shift(lvl + 1);
 131
 132         GEM_BUG_ON(start >= end);
 133         return (start ^ end) & mask && (start & ~mask) == 0;
 134 }
 135
 136 static inline unsigned int gen8_pt_count(u64 start, u64 end)
 137 {
 138         GEM_BUG_ON(start >= end);
 139         if ((start ^ end) >> gen8_pd_shift(1))
 140                 return GEN8_PDES - (start & (GEN8_PDES - 1));
 141         else
 142                 return end - start;
 143 }
 144
 145 static inline unsigned int
 146 gen8_pd_top_count(const struct i915_address_space *vm)
 147 {
 148         unsigned int shift = __gen8_pte_shift(vm->top);
 149         return (vm->total + (1ull << shift) - 1) >> shift;
 150 }
 151
 152 static inline struct i915_page_directory *
 153 gen8_pdp_for_page_index(struct i915_address_space * const vm, const u64 idx)
 154 {
 155         struct i915_ppgtt * const ppgtt = i915_vm_to_ppgtt(vm);
 156
 157         if (vm->top == 2)
 158                 return ppgtt->pd;
 159         else
 160                 return i915_pd_entry(ppgtt->pd, gen8_pd_index(idx, vm->top));
 161 }
 162
 163 static inline struct i915_page_directory *
 164 gen8_pdp_for_page_address(struct i915_address_space * const vm, const u64 addr)
 165 {
 166         return gen8_pdp_for_page_index(vm, addr >> GEN8_PTE_SHIFT);
 167 }
 168
 169 static void __gen8_ppgtt_cleanup(struct i915_address_space *vm,
 170                                  struct i915_page_directory *pd,
 171                                  int count, int lvl)
 172 {
 173         if (lvl) {
 174                 void **pde = pd->entry;
 175
 176                 do {
 177                         if (!*pde)
 178                                 continue;
 179
 180                         __gen8_ppgtt_cleanup(vm, *pde, GEN8_PDES, lvl - 1);
 181                 } while (pde++, --count);
 182         }
 183
 184         free_px(vm, &pd->pt, lvl);
 185 }
 186
 187 static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
 188 {
 189         struct i915_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
 190
 191         if (intel_vgpu_active(vm->i915))
 192                 gen8_ppgtt_notify_vgt(ppgtt, false);
 193
 194         __gen8_ppgtt_cleanup(vm, ppgtt->pd, gen8_pd_top_count(vm), vm->top);
 195         free_scratch(vm);
 196 }
 197
 198 static u64 __gen8_ppgtt_clear(struct i915_address_space * const vm,
 199                               struct i915_page_directory * const pd,
 200                               u64 start, const u64 end, int lvl)
 201 {
 202         const struct drm_i915_gem_object * const scratch = vm->scratch[lvl];
 203         unsigned int idx, len;
 204
 205         GEM_BUG_ON(end > vm->total >> GEN8_PTE_SHIFT);
 206
 207         len = gen8_pd_range(start, end, lvl--, &idx);
 208         DBG("%s(%p):{ lvl:%d, start:%llx, end:%llx, idx:%d, len:%d, used:%d }\n",
 209             __func__, vm, lvl + 1, start, end,
 210             idx, len, atomic_read(px_used(pd)));
 211         GEM_BUG_ON(!len || len >= atomic_read(px_used(pd)));
 212
 213         do {
 214                 struct i915_page_table *pt = pd->entry[idx];
 215
 216                 if (atomic_fetch_inc(&pt->used) >> gen8_pd_shift(1) &&
 217                     gen8_pd_contains(start, end, lvl)) {
 218                         DBG("%s(%p):{ lvl:%d, idx:%d, start:%llx, end:%llx } removing pd\n",
 219                             __func__, vm, lvl + 1, idx, start, end);
 220                         clear_pd_entry(pd, idx, scratch);
 221                         __gen8_ppgtt_cleanup(vm, as_pd(pt), I915_PDES, lvl);
 222                         start += (u64)I915_PDES << gen8_pd_shift(lvl);
 223                         continue;
 224                 }
 225
 226                 if (lvl) {
 227                         start = __gen8_ppgtt_clear(vm, as_pd(pt),
 228                                                    start, end, lvl);
 229                 } else {
 230                         unsigned int count;
 231                         u64 *vaddr;
 232
 233                         count = gen8_pt_count(start, end);
 234                         DBG("%s(%p):{ lvl:%d, start:%llx, end:%llx, idx:%d, len:%d, used:%d } removing pte\n",
 235                             __func__, vm, lvl, start, end,
 236                             gen8_pd_index(start, 0), count,
 237                             atomic_read(&pt->used));
 238                         GEM_BUG_ON(!count || count >= atomic_read(&pt->used));
 239
 240                         vaddr = kmap_atomic_px(pt);
 241                         memset64(vaddr + gen8_pd_index(start, 0),
 242                                  vm->scratch[0]->encode,
 243                                  count);
 244                         kunmap_atomic(vaddr);
 245
 246                         atomic_sub(count, &pt->used);
 247                         start += count;
 248                 }
 249
 250                 if (release_pd_entry(pd, idx, pt, scratch))
 251                         free_px(vm, pt, lvl);
 252         } while (idx++, --len);
 253
 254         return start;
 255 }
 256
 257 static void gen8_ppgtt_clear(struct i915_address_space *vm,
 258                              u64 start, u64 length)
 259 {
 260         GEM_BUG_ON(!IS_ALIGNED(start, BIT_ULL(GEN8_PTE_SHIFT)));
 261         GEM_BUG_ON(!IS_ALIGNED(length, BIT_ULL(GEN8_PTE_SHIFT)));
 262         GEM_BUG_ON(range_overflows(start, length, vm->total));
 263
 264         start >>= GEN8_PTE_SHIFT;
 265         length >>= GEN8_PTE_SHIFT;
 266         GEM_BUG_ON(length == 0);
 267
 268         __gen8_ppgtt_clear(vm, i915_vm_to_ppgtt(vm)->pd,
 269                            start, start + length, vm->top);
 270 }
 271
 272 static void __gen8_ppgtt_alloc(struct i915_address_space * const vm,
 273                                struct i915_vm_pt_stash *stash,
 274                                struct i915_page_directory * const pd,
 275                                u64 * const start, const u64 end, int lvl)
 276 {
 277         unsigned int idx, len;
 278
 279         GEM_BUG_ON(end > vm->total >> GEN8_PTE_SHIFT);
 280
 281         len = gen8_pd_range(*start, end, lvl--, &idx);
 282         DBG("%s(%p):{ lvl:%d, start:%llx, end:%llx, idx:%d, len:%d, used:%d }\n",
 283             __func__, vm, lvl + 1, *start, end,
 284             idx, len, atomic_read(px_used(pd)));
 285         GEM_BUG_ON(!len || (idx + len - 1) >> gen8_pd_shift(1));
 286
 287         spin_lock(&pd->lock);
 288         GEM_BUG_ON(!atomic_read(px_used(pd))); /* Must be pinned! */
 289         do {
 290                 struct i915_page_table *pt = pd->entry[idx];
 291
 292                 if (!pt) {
 293                         spin_unlock(&pd->lock);
 294
 295                         DBG("%s(%p):{ lvl:%d, idx:%d } allocating new tree\n",
 296                             __func__, vm, lvl + 1, idx);
 297
 298                         pt = stash->pt[!!lvl];
 299                         __i915_gem_object_pin_pages(pt->base);
 300                         i915_gem_object_make_unshrinkable(pt->base);
 301
 302                         if (lvl ||
 303                             gen8_pt_count(*start, end) < I915_PDES ||
 304                             intel_vgpu_active(vm->i915))
 305                                 fill_px(pt, vm->scratch[lvl]->encode);
 306
 307                         spin_lock(&pd->lock);
 308                         if (likely(!pd->entry[idx])) {
 309                                 stash->pt[!!lvl] = pt->stash;
 310                                 atomic_set(&pt->used, 0);
 311                                 set_pd_entry(pd, idx, pt);
 312                         } else {
 313                                 pt = pd->entry[idx];
 314                         }
 315                 }
 316
 317                 if (lvl) {
 318                         atomic_inc(&pt->used);
 319                         spin_unlock(&pd->lock);
 320
 321                         __gen8_ppgtt_alloc(vm, stash,
 322                                            as_pd(pt), start, end, lvl);
 323
 324                         spin_lock(&pd->lock);
 325                         atomic_dec(&pt->used);
 326                         GEM_BUG_ON(!atomic_read(&pt->used));
 327                 } else {
 328                         unsigned int count = gen8_pt_count(*start, end);
 329
 330                         DBG("%s(%p):{ lvl:%d, start:%llx, end:%llx, idx:%d, len:%d, used:%d } inserting pte\n",
 331                             __func__, vm, lvl, *start, end,
 332                             gen8_pd_index(*start, 0), count,
 333                             atomic_read(&pt->used));
 334
 335                         atomic_add(count, &pt->used);
 336                         /* All other pdes may be simultaneously removed */
 337                         GEM_BUG_ON(atomic_read(&pt->used) > NALLOC * I915_PDES);
 338                         *start += count;
 339                 }
 340         } while (idx++, --len);
 341         spin_unlock(&pd->lock);
 342 }
 343
 344 static void gen8_ppgtt_alloc(struct i915_address_space *vm,
 345                              struct i915_vm_pt_stash *stash,
 346                              u64 start, u64 length)
 347 {
 348         GEM_BUG_ON(!IS_ALIGNED(start, BIT_ULL(GEN8_PTE_SHIFT)));
 349         GEM_BUG_ON(!IS_ALIGNED(length, BIT_ULL(GEN8_PTE_SHIFT)));
 350         GEM_BUG_ON(range_overflows(start, length, vm->total));
 351
 352         start >>= GEN8_PTE_SHIFT;
 353         length >>= GEN8_PTE_SHIFT;
 354         GEM_BUG_ON(length == 0);
 355
 356         __gen8_ppgtt_alloc(vm, stash, i915_vm_to_ppgtt(vm)->pd,
 357                            &start, start + length, vm->top);
 358 }
 359
 360 static __always_inline u64
 361 gen8_ppgtt_insert_pte(struct i915_ppgtt *ppgtt,
 362                       struct i915_page_directory *pdp,
 363                       struct sgt_dma *iter,
 364                       u64 idx,
 365                       enum i915_cache_level cache_level,
 366                       u32 flags)
 367 {
 368         struct i915_page_directory *pd;
 369         const gen8_pte_t pte_encode = gen8_pte_encode(0, cache_level, flags);
 370         gen8_pte_t *vaddr;
 371
 372         pd = i915_pd_entry(pdp, gen8_pd_index(idx, 2));
 373         vaddr = kmap_atomic_px(i915_pt_entry(pd, gen8_pd_index(idx, 1)));
 374         do {
 375                 GEM_BUG_ON(sg_dma_len(iter->sg) < I915_GTT_PAGE_SIZE);
 376                 vaddr[gen8_pd_index(idx, 0)] = pte_encode | iter->dma;
 377
 378                 iter->dma += I915_GTT_PAGE_SIZE;
 379                 if (iter->dma >= iter->max) {
 380                         iter->sg = __sg_next(iter->sg);
 381                         if (!iter->sg || sg_dma_len(iter->sg) == 0) {
 382                                 idx = 0;
 383                                 break;
 384                         }
 385
 386                         iter->dma = sg_dma_address(iter->sg);
 387                         iter->max = iter->dma + sg_dma_len(iter->sg);
 388                 }
 389
 390                 if (gen8_pd_index(++idx, 0) == 0) {
 391                         if (gen8_pd_index(idx, 1) == 0) {
 392                                 /* Limited by sg length for 3lvl */
 393                                 if (gen8_pd_index(idx, 2) == 0)
 394                                         break;
 395
 396                                 pd = pdp->entry[gen8_pd_index(idx, 2)];
 397                         }
 398
 399                         clflush_cache_range(vaddr, PAGE_SIZE);
 400                         kunmap_atomic(vaddr);
 401                         vaddr = kmap_atomic_px(i915_pt_entry(pd, gen8_pd_index(idx, 1)));
 402                 }
 403         } while (1);
 404         clflush_cache_range(vaddr, PAGE_SIZE);
 405         kunmap_atomic(vaddr);
 406
 407         return idx;
 408 }
 409
 410 static void gen8_ppgtt_insert_huge(struct i915_vma *vma,
 411                                    struct sgt_dma *iter,
 412                                    enum i915_cache_level cache_level,
 413                                    u32 flags)
 414 {
 415         const gen8_pte_t pte_encode = gen8_pte_encode(0, cache_level, flags);
 416         unsigned int rem = sg_dma_len(iter->sg);
 417         u64 start = vma->node.start;
 418
 419         GEM_BUG_ON(!i915_vm_is_4lvl(vma->vm));
 420
 421         do {
 422                 struct i915_page_directory * const pdp =
 423                         gen8_pdp_for_page_address(vma->vm, start);
 424                 struct i915_page_directory * const pd =
 425                         i915_pd_entry(pdp, __gen8_pte_index(start, 2));
 426                 gen8_pte_t encode = pte_encode;
 427                 unsigned int maybe_64K = -1;
 428                 unsigned int page_size;
 429                 gen8_pte_t *vaddr;
 430                 u16 index;
 431
 432                 if (vma->page_sizes.sg & I915_GTT_PAGE_SIZE_2M &&
 433                     IS_ALIGNED(iter->dma, I915_GTT_PAGE_SIZE_2M) &&
 434                     rem >= I915_GTT_PAGE_SIZE_2M &&
 435                     !__gen8_pte_index(start, 0)) {
 436                         index = __gen8_pte_index(start, 1);
 437                         encode |= GEN8_PDE_PS_2M;
 438                         page_size = I915_GTT_PAGE_SIZE_2M;
 439
 440                         vaddr = kmap_atomic_px(pd);
 441                 } else {
 442                         struct i915_page_table *pt =
 443                                 i915_pt_entry(pd, __gen8_pte_index(start, 1));
 444
 445                         index = __gen8_pte_index(start, 0);
 446                         page_size = I915_GTT_PAGE_SIZE;
 447
 448                         if (!index &&
 449                             vma->page_sizes.sg & I915_GTT_PAGE_SIZE_64K &&
 450                             IS_ALIGNED(iter->dma, I915_GTT_PAGE_SIZE_64K) &&
 451                             (IS_ALIGNED(rem, I915_GTT_PAGE_SIZE_64K) ||
 452                              rem >= (I915_PDES - index) * I915_GTT_PAGE_SIZE))
 453                                 maybe_64K = __gen8_pte_index(start, 1);
 454
 455                         vaddr = kmap_atomic_px(pt);
 456                 }
 457
 458                 do {
 459                         GEM_BUG_ON(sg_dma_len(iter->sg) < page_size);
 460                         vaddr[index++] = encode | iter->dma;
 461
 462                         start += page_size;
 463                         iter->dma += page_size;
 464                         rem -= page_size;
 465                         if (iter->dma >= iter->max) {
 466                                 iter->sg = __sg_next(iter->sg);
 467                                 if (!iter->sg)
 468                                         break;
 469
 470                                 rem = sg_dma_len(iter->sg);
 471                                 if (!rem)
 472                                         break;
 473
 474                                 iter->dma = sg_dma_address(iter->sg);
 475                                 iter->max = iter->dma + rem;
 476
 477                                 if (maybe_64K != -1 && index < I915_PDES &&
 478                                     !(IS_ALIGNED(iter->dma, I915_GTT_PAGE_SIZE_64K) &&
 479                                       (IS_ALIGNED(rem, I915_GTT_PAGE_SIZE_64K) ||
 480                                        rem >= (I915_PDES - index) * I915_GTT_PAGE_SIZE)))
 481                                         maybe_64K = -1;
 482
 483                                 if (unlikely(!IS_ALIGNED(iter->dma, page_size)))
 484                                         break;
 485                         }
 486                 } while (rem >= page_size && index < I915_PDES);
 487
 488                 clflush_cache_range(vaddr, PAGE_SIZE);
 489                 kunmap_atomic(vaddr);
 490
 491                 /*
 492                  * Is it safe to mark the 2M block as 64K? -- Either we have
 493                  * filled whole page-table with 64K entries, or filled part of
 494                  * it and have reached the end of the sg table and we have
 495                  * enough padding.
 496                  */
 497                 if (maybe_64K != -1 &&
 498                     (index == I915_PDES ||
 499                      (i915_vm_has_scratch_64K(vma->vm) &&
 500                       !iter->sg && IS_ALIGNED(vma->node.start +
 501                                               vma->node.size,
 502                                               I915_GTT_PAGE_SIZE_2M)))) {
 503                         vaddr = kmap_atomic_px(pd);
 504                         vaddr[maybe_64K] |= GEN8_PDE_IPS_64K;
 505                         kunmap_atomic(vaddr);
 506                         page_size = I915_GTT_PAGE_SIZE_64K;
 507
 508                         /*
 509                          * We write all 4K page entries, even when using 64K
 510                          * pages. In order to verify that the HW isn't cheating
 511                          * by using the 4K PTE instead of the 64K PTE, we want
 512                          * to remove all the surplus entries. If the HW skipped
 513                          * the 64K PTE, it will read/write into the scratch page
 514                          * instead - which we detect as missing results during
 515                          * selftests.
 516                          */
 517                         if (I915_SELFTEST_ONLY(vma->vm->scrub_64K)) {
 518                                 u16 i;
 519
 520                                 encode = vma->vm->scratch[0]->encode;
 521                                 vaddr = kmap_atomic_px(i915_pt_entry(pd, maybe_64K));
 522
 523                                 for (i = 1; i < index; i += 16)
 524                                         memset64(vaddr + i, encode, 15);
 525
 526                                 kunmap_atomic(vaddr);
 527                         }
 528                 }
 529
 530                 vma->page_sizes.gtt |= page_size;
 531         } while (iter->sg && sg_dma_len(iter->sg));
 532 }
 533
 534 static void gen8_ppgtt_insert(struct i915_address_space *vm,
 535                               struct i915_vma *vma,
 536                               enum i915_cache_level cache_level,
 537                               u32 flags)
 538 {
 539         struct i915_ppgtt * const ppgtt = i915_vm_to_ppgtt(vm);
 540         struct sgt_dma iter = sgt_dma(vma);
 541
 542         if (vma->page_sizes.sg > I915_GTT_PAGE_SIZE) {
 543                 gen8_ppgtt_insert_huge(vma, &iter, cache_level, flags);
 544         } else  {
 545                 u64 idx = vma->node.start >> GEN8_PTE_SHIFT;
 546
 547                 do {
 548                         struct i915_page_directory * const pdp =
 549                                 gen8_pdp_for_page_index(vm, idx);
 550
 551                         idx = gen8_ppgtt_insert_pte(ppgtt, pdp, &iter, idx,
 552                                                     cache_level, flags);
 553                 } while (idx);
 554
 555                 vma->page_sizes.gtt = I915_GTT_PAGE_SIZE;
 556         }
 557 }
 558
 559 static int gen8_init_scratch(struct i915_address_space *vm)
 560 {
 561         int ret;
 562         int i;
 563
 564         /*
 565          * If everybody agrees to not to write into the scratch page,
 566          * we can reuse it for all vm, keeping contexts and processes separate.
 567          */
 568         if (vm->has_read_only && vm->gt->vm && !i915_is_ggtt(vm->gt->vm)) {
 569                 struct i915_address_space *clone = vm->gt->vm;
 570
 571                 GEM_BUG_ON(!clone->has_read_only);
 572
 573                 vm->scratch_order = clone->scratch_order;
 574                 for (i = 0; i <= vm->top; i++)
 575                         vm->scratch[i] = i915_gem_object_get(clone->scratch[i]);
 576
 577                 return 0;
 578         }
 579
 580         ret = setup_scratch_page(vm);
 581         if (ret)
 582                 return ret;
 583
 584         vm->scratch[0]->encode =
 585                 gen8_pte_encode(px_dma(vm->scratch[0]),
 586                                 I915_CACHE_LLC, vm->has_read_only);
 587
 588         for (i = 1; i <= vm->top; i++) {
 589                 struct drm_i915_gem_object *obj;
 590
 591                 obj = vm->alloc_pt_dma(vm, I915_GTT_PAGE_SIZE_4K);
 592                 if (IS_ERR(obj))
 593                         goto free_scratch;
 594
 595                 ret = pin_pt_dma(vm, obj);
 596                 if (ret) {
 597                         i915_gem_object_put(obj);
 598                         goto free_scratch;
 599                 }
 600
 601                 fill_px(obj, vm->scratch[i - 1]->encode);
 602                 obj->encode = gen8_pde_encode(px_dma(obj), I915_CACHE_LLC);
 603
 604                 vm->scratch[i] = obj;
 605         }
 606
 607         return 0;
 608
 609 free_scratch:
 610         while (i--)
 611                 i915_gem_object_put(vm->scratch[i]);
 612         return -ENOMEM;
 613 }
 614
 615 static int gen8_preallocate_top_level_pdp(struct i915_ppgtt *ppgtt)
 616 {
 617         struct i915_address_space *vm = &ppgtt->vm;
 618         struct i915_page_directory *pd = ppgtt->pd;
 619         unsigned int idx;
 620
 621         GEM_BUG_ON(vm->top != 2);
 622         GEM_BUG_ON(gen8_pd_top_count(vm) != GEN8_3LVL_PDPES);
 623
 624         for (idx = 0; idx < GEN8_3LVL_PDPES; idx++) {
 625                 struct i915_page_directory *pde;
 626                 int err;
 627
 628                 pde = alloc_pd(vm);
 629                 if (IS_ERR(pde))
 630                         return PTR_ERR(pde);
 631
 632                 err = pin_pt_dma(vm, pde->pt.base);
 633                 if (err) {
 634                         i915_gem_object_put(pde->pt.base);
 635                         free_pd(vm, pde);
 636                         return err;
 637                 }
 638
 639                 fill_px(pde, vm->scratch[1]->encode);
 640                 set_pd_entry(pd, idx, pde);
 641                 atomic_inc(px_used(pde)); /* keep pinned */
 642         }
 643         wmb();
 644
 645         return 0;
 646 }
 647
 648 static struct i915_page_directory *
 649 gen8_alloc_top_pd(struct i915_address_space *vm)
 650 {
 651         const unsigned int count = gen8_pd_top_count(vm);
 652         struct i915_page_directory *pd;
 653         int err;
 654
 655         GEM_BUG_ON(count > I915_PDES);
 656
 657         pd = __alloc_pd(count);
 658         if (unlikely(!pd))
 659                 return ERR_PTR(-ENOMEM);
 660
 661         pd->pt.base = vm->alloc_pt_dma(vm, I915_GTT_PAGE_SIZE_4K);
 662         if (IS_ERR(pd->pt.base)) {
 663                 err = PTR_ERR(pd->pt.base);
 664                 pd->pt.base = NULL;
 665                 goto err_pd;
 666         }
 667
 668         err = pin_pt_dma(vm, pd->pt.base);
 669         if (err)
 670                 goto err_pd;
 671
 672         fill_page_dma(px_base(pd), vm->scratch[vm->top]->encode, count);
 673         atomic_inc(px_used(pd)); /* mark as pinned */
 674         return pd;
 675
 676 err_pd:
 677         free_pd(vm, pd);
 678         return ERR_PTR(err);
 679 }
 680
 681 /*
 682  * GEN8 legacy ppgtt programming is accomplished through a max 4 PDP registers
 683  * with a net effect resembling a 2-level page table in normal x86 terms. Each
 684  * PDP represents 1GB of memory 4 * 512 * 512 * 4096 = 4GB legacy 32b address
 685  * space.
 686  *
 687  */
 688 struct i915_ppgtt *gen8_ppgtt_create(struct intel_gt *gt)
 689 {
 690         struct i915_ppgtt *ppgtt;
 691         int err;
 692
 693         ppgtt = kzalloc(sizeof(*ppgtt), GFP_KERNEL);
 694         if (!ppgtt)
 695                 return ERR_PTR(-ENOMEM);
 696
 697         ppgtt_init(ppgtt, gt);
 698         ppgtt->vm.top = i915_vm_is_4lvl(&ppgtt->vm) ? 3 : 2;
 699         ppgtt->vm.pd_shift = ilog2(SZ_4K * SZ_4K / sizeof(gen8_pte_t));
 700
 701         /*
 702          * From bdw, there is hw support for read-only pages in the PPGTT.
 703          *
 704          * Gen11 has HSDES#:1807136187 unresolved. Disable ro support
 705          * for now.
 706          *
 707          * Gen12 has inherited the same read-only fault issue from gen11.
 708          */
 709         ppgtt->vm.has_read_only = !IS_GEN_RANGE(gt->i915, 11, 12);
 710
 711         ppgtt->vm.alloc_pt_dma = alloc_pt_dma;
 712
 713         err = gen8_init_scratch(&ppgtt->vm);
 714         if (err)
 715                 goto err_free;
 716
 717         ppgtt->pd = gen8_alloc_top_pd(&ppgtt->vm);
 718         if (IS_ERR(ppgtt->pd)) {
 719                 err = PTR_ERR(ppgtt->pd);
 720                 goto err_free_scratch;
 721         }
 722
 723         if (!i915_vm_is_4lvl(&ppgtt->vm)) {
 724                 err = gen8_preallocate_top_level_pdp(ppgtt);
 725                 if (err)
 726                         goto err_free_pd;
 727         }
 728
 729         ppgtt->vm.bind_async_flags = I915_VMA_LOCAL_BIND;
 730         ppgtt->vm.insert_entries = gen8_ppgtt_insert;
 731         ppgtt->vm.allocate_va_range = gen8_ppgtt_alloc;
 732         ppgtt->vm.clear_range = gen8_ppgtt_clear;
 733
 734         ppgtt->vm.pte_encode = gen8_pte_encode;
 735
 736         if (intel_vgpu_active(gt->i915))
 737                 gen8_ppgtt_notify_vgt(ppgtt, true);
 738
 739         ppgtt->vm.cleanup = gen8_ppgtt_cleanup;
 740
 741         return ppgtt;
 742
 743 err_free_pd:
 744         __gen8_ppgtt_cleanup(&ppgtt->vm, ppgtt->pd,
 745                              gen8_pd_top_count(&ppgtt->vm), ppgtt->vm.top);
 746 err_free_scratch:
 747         free_scratch(&ppgtt->vm);
 748 err_free:
 749         kfree(ppgtt);
 750         return ERR_PTR(err);
 751 }