arch/riscv/kvm/mmu.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2019 Western Digital Corporation or its affiliates.
   4  *
   5  * Authors:
   6  *     Anup Patel <anup.patel@wdc.com>
   7  */
   8
   9 #include <linux/bitops.h>
  10 #include <linux/errno.h>
  11 #include <linux/err.h>
  12 #include <linux/hugetlb.h>
  13 #include <linux/module.h>
  14 #include <linux/uaccess.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/kvm_host.h>
  17 #include <linux/sched/signal.h>
  18 #include <asm/kvm_nacl.h>
  19 #include <asm/page.h>
  20 #include <asm/pgtable.h>
  21
  22 #ifdef CONFIG_64BIT
  23 static unsigned long gstage_mode __ro_after_init = (HGATP_MODE_SV39X4 << HGATP_MODE_SHIFT);
  24 static unsigned long gstage_pgd_levels __ro_after_init = 3;
  25 #define gstage_index_bits       9
  26 #else
  27 static unsigned long gstage_mode __ro_after_init = (HGATP_MODE_SV32X4 << HGATP_MODE_SHIFT);
  28 static unsigned long gstage_pgd_levels __ro_after_init = 2;
  29 #define gstage_index_bits       10
  30 #endif
  31
  32 #define gstage_pgd_xbits        2
  33 #define gstage_pgd_size (1UL << (HGATP_PAGE_SHIFT + gstage_pgd_xbits))
  34 #define gstage_gpa_bits (HGATP_PAGE_SHIFT + \
  35                          (gstage_pgd_levels * gstage_index_bits) + \
  36                          gstage_pgd_xbits)
  37 #define gstage_gpa_size ((gpa_t)(1ULL << gstage_gpa_bits))
  38
  39 #define gstage_pte_leaf(__ptep) \
  40         (pte_val(*(__ptep)) & (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC))
  41
  42 static inline unsigned long gstage_pte_index(gpa_t addr, u32 level)
  43 {
  44         unsigned long mask;
  45         unsigned long shift = HGATP_PAGE_SHIFT + (gstage_index_bits * level);
  46
  47         if (level == (gstage_pgd_levels - 1))
  48                 mask = (PTRS_PER_PTE * (1UL << gstage_pgd_xbits)) - 1;
  49         else
  50                 mask = PTRS_PER_PTE - 1;
  51
  52         return (addr >> shift) & mask;
  53 }
  54
  55 static inline unsigned long gstage_pte_page_vaddr(pte_t pte)
  56 {
  57         return (unsigned long)pfn_to_virt(__page_val_to_pfn(pte_val(pte)));
  58 }
  59
  60 static int gstage_page_size_to_level(unsigned long page_size, u32 *out_level)
  61 {
  62         u32 i;
  63         unsigned long psz = 1UL << 12;
  64
  65         for (i = 0; i < gstage_pgd_levels; i++) {
  66                 if (page_size == (psz << (i * gstage_index_bits))) {
  67                         *out_level = i;
  68                         return 0;
  69                 }
  70         }
  71
  72         return -EINVAL;
  73 }
  74
  75 static int gstage_level_to_page_order(u32 level, unsigned long *out_pgorder)
  76 {
  77         if (gstage_pgd_levels < level)
  78                 return -EINVAL;
  79
  80         *out_pgorder = 12 + (level * gstage_index_bits);
  81         return 0;
  82 }
  83
  84 static int gstage_level_to_page_size(u32 level, unsigned long *out_pgsize)
  85 {
  86         int rc;
  87         unsigned long page_order = PAGE_SHIFT;
  88
  89         rc = gstage_level_to_page_order(level, &page_order);
  90         if (rc)
  91                 return rc;
  92
  93         *out_pgsize = BIT(page_order);
  94         return 0;
  95 }
  96
  97 static bool gstage_get_leaf_entry(struct kvm *kvm, gpa_t addr,
  98                                   pte_t **ptepp, u32 *ptep_level)
  99 {
 100         pte_t *ptep;
 101         u32 current_level = gstage_pgd_levels - 1;
 102
 103         *ptep_level = current_level;
 104         ptep = (pte_t *)kvm->arch.pgd;
 105         ptep = &ptep[gstage_pte_index(addr, current_level)];
 106         while (ptep && pte_val(ptep_get(ptep))) {
 107                 if (gstage_pte_leaf(ptep)) {
 108                         *ptep_level = current_level;
 109                         *ptepp = ptep;
 110                         return true;
 111                 }
 112
 113                 if (current_level) {
 114                         current_level--;
 115                         *ptep_level = current_level;
 116                         ptep = (pte_t *)gstage_pte_page_vaddr(ptep_get(ptep));
 117                         ptep = &ptep[gstage_pte_index(addr, current_level)];
 118                 } else {
 119                         ptep = NULL;
 120                 }
 121         }
 122
 123         return false;
 124 }
 125
 126 static void gstage_remote_tlb_flush(struct kvm *kvm, u32 level, gpa_t addr)
 127 {
 128         unsigned long order = PAGE_SHIFT;
 129
 130         if (gstage_level_to_page_order(level, &order))
 131                 return;
 132         addr &= ~(BIT(order) - 1);
 133
 134         kvm_riscv_hfence_gvma_vmid_gpa(kvm, -1UL, 0, addr, BIT(order), order);
 135 }
 136
 137 static int gstage_set_pte(struct kvm *kvm, u32 level,
 138                            struct kvm_mmu_memory_cache *pcache,
 139                            gpa_t addr, const pte_t *new_pte)
 140 {
 141         u32 current_level = gstage_pgd_levels - 1;
 142         pte_t *next_ptep = (pte_t *)kvm->arch.pgd;
 143         pte_t *ptep = &next_ptep[gstage_pte_index(addr, current_level)];
 144
 145         if (current_level < level)
 146                 return -EINVAL;
 147
 148         while (current_level != level) {
 149                 if (gstage_pte_leaf(ptep))
 150                         return -EEXIST;
 151
 152                 if (!pte_val(ptep_get(ptep))) {
 153                         if (!pcache)
 154                                 return -ENOMEM;
 155                         next_ptep = kvm_mmu_memory_cache_alloc(pcache);
 156                         if (!next_ptep)
 157                                 return -ENOMEM;
 158                         set_pte(ptep, pfn_pte(PFN_DOWN(__pa(next_ptep)),
 159                                               __pgprot(_PAGE_TABLE)));
 160                 } else {
 161                         if (gstage_pte_leaf(ptep))
 162                                 return -EEXIST;
 163                         next_ptep = (pte_t *)gstage_pte_page_vaddr(ptep_get(ptep));
 164                 }
 165
 166                 current_level--;
 167                 ptep = &next_ptep[gstage_pte_index(addr, current_level)];
 168         }
 169
 170         set_pte(ptep, *new_pte);
 171         if (gstage_pte_leaf(ptep))
 172                 gstage_remote_tlb_flush(kvm, current_level, addr);
 173
 174         return 0;
 175 }
 176
 177 static int gstage_map_page(struct kvm *kvm,
 178                            struct kvm_mmu_memory_cache *pcache,
 179                            gpa_t gpa, phys_addr_t hpa,
 180                            unsigned long page_size,
 181                            bool page_rdonly, bool page_exec)
 182 {
 183         int ret;
 184         u32 level = 0;
 185         pte_t new_pte;
 186         pgprot_t prot;
 187
 188         ret = gstage_page_size_to_level(page_size, &level);
 189         if (ret)
 190                 return ret;
 191
 192         /*
 193          * A RISC-V implementation can choose to either:
 194          * 1) Update 'A' and 'D' PTE bits in hardware
 195          * 2) Generate page fault when 'A' and/or 'D' bits are not set
 196          *    PTE so that software can update these bits.
 197          *
 198          * We support both options mentioned above. To achieve this, we
 199          * always set 'A' and 'D' PTE bits at time of creating G-stage
 200          * mapping. To support KVM dirty page logging with both options
 201          * mentioned above, we will write-protect G-stage PTEs to track
 202          * dirty pages.
 203          */
 204
 205         if (page_exec) {
 206                 if (page_rdonly)
 207                         prot = PAGE_READ_EXEC;
 208                 else
 209                         prot = PAGE_WRITE_EXEC;
 210         } else {
 211                 if (page_rdonly)
 212                         prot = PAGE_READ;
 213                 else
 214                         prot = PAGE_WRITE;
 215         }
 216         new_pte = pfn_pte(PFN_DOWN(hpa), prot);
 217         new_pte = pte_mkdirty(new_pte);
 218
 219         return gstage_set_pte(kvm, level, pcache, gpa, &new_pte);
 220 }
 221
 222 enum gstage_op {
 223         GSTAGE_OP_NOP = 0,      /* Nothing */
 224         GSTAGE_OP_CLEAR,        /* Clear/Unmap */
 225         GSTAGE_OP_WP,           /* Write-protect */
 226 };
 227
 228 static void gstage_op_pte(struct kvm *kvm, gpa_t addr,
 229                           pte_t *ptep, u32 ptep_level, enum gstage_op op)
 230 {
 231         int i, ret;
 232         pte_t *next_ptep;
 233         u32 next_ptep_level;
 234         unsigned long next_page_size, page_size;
 235
 236         ret = gstage_level_to_page_size(ptep_level, &page_size);
 237         if (ret)
 238                 return;
 239
 240         BUG_ON(addr & (page_size - 1));
 241
 242         if (!pte_val(ptep_get(ptep)))
 243                 return;
 244
 245         if (ptep_level && !gstage_pte_leaf(ptep)) {
 246                 next_ptep = (pte_t *)gstage_pte_page_vaddr(ptep_get(ptep));
 247                 next_ptep_level = ptep_level - 1;
 248                 ret = gstage_level_to_page_size(next_ptep_level,
 249                                                 &next_page_size);
 250                 if (ret)
 251                         return;
 252
 253                 if (op == GSTAGE_OP_CLEAR)
 254                         set_pte(ptep, __pte(0));
 255                 for (i = 0; i < PTRS_PER_PTE; i++)
 256                         gstage_op_pte(kvm, addr + i * next_page_size,
 257                                         &next_ptep[i], next_ptep_level, op);
 258                 if (op == GSTAGE_OP_CLEAR)
 259                         put_page(virt_to_page(next_ptep));
 260         } else {
 261                 if (op == GSTAGE_OP_CLEAR)
 262                         set_pte(ptep, __pte(0));
 263                 else if (op == GSTAGE_OP_WP)
 264                         set_pte(ptep, __pte(pte_val(ptep_get(ptep)) & ~_PAGE_WRITE));
 265                 gstage_remote_tlb_flush(kvm, ptep_level, addr);
 266         }
 267 }
 268
 269 static void gstage_unmap_range(struct kvm *kvm, gpa_t start,
 270                                gpa_t size, bool may_block)
 271 {
 272         int ret;
 273         pte_t *ptep;
 274         u32 ptep_level;
 275         bool found_leaf;
 276         unsigned long page_size;
 277         gpa_t addr = start, end = start + size;
 278
 279         while (addr < end) {
 280                 found_leaf = gstage_get_leaf_entry(kvm, addr,
 281                                                    &ptep, &ptep_level);
 282                 ret = gstage_level_to_page_size(ptep_level, &page_size);
 283                 if (ret)
 284                         break;
 285
 286                 if (!found_leaf)
 287                         goto next;
 288
 289                 if (!(addr & (page_size - 1)) && ((end - addr) >= page_size))
 290                         gstage_op_pte(kvm, addr, ptep,
 291                                       ptep_level, GSTAGE_OP_CLEAR);
 292
 293 next:
 294                 addr += page_size;
 295
 296                 /*
 297                  * If the range is too large, release the kvm->mmu_lock
 298                  * to prevent starvation and lockup detector warnings.
 299                  */
 300                 if (may_block && addr < end)
 301                         cond_resched_lock(&kvm->mmu_lock);
 302         }
 303 }
 304
 305 static void gstage_wp_range(struct kvm *kvm, gpa_t start, gpa_t end)
 306 {
 307         int ret;
 308         pte_t *ptep;
 309         u32 ptep_level;
 310         bool found_leaf;
 311         gpa_t addr = start;
 312         unsigned long page_size;
 313
 314         while (addr < end) {
 315                 found_leaf = gstage_get_leaf_entry(kvm, addr,
 316                                                    &ptep, &ptep_level);
 317                 ret = gstage_level_to_page_size(ptep_level, &page_size);
 318                 if (ret)
 319                         break;
 320
 321                 if (!found_leaf)
 322                         goto next;
 323
 324                 if (!(addr & (page_size - 1)) && ((end - addr) >= page_size))
 325                         gstage_op_pte(kvm, addr, ptep,
 326                                       ptep_level, GSTAGE_OP_WP);
 327
 328 next:
 329                 addr += page_size;
 330         }
 331 }
 332
 333 static void gstage_wp_memory_region(struct kvm *kvm, int slot)
 334 {
 335         struct kvm_memslots *slots = kvm_memslots(kvm);
 336         struct kvm_memory_slot *memslot = id_to_memslot(slots, slot);
 337         phys_addr_t start = memslot->base_gfn << PAGE_SHIFT;
 338         phys_addr_t end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;
 339
 340         spin_lock(&kvm->mmu_lock);
 341         gstage_wp_range(kvm, start, end);
 342         spin_unlock(&kvm->mmu_lock);
 343         kvm_flush_remote_tlbs(kvm);
 344 }
 345
 346 int kvm_riscv_gstage_ioremap(struct kvm *kvm, gpa_t gpa,
 347                              phys_addr_t hpa, unsigned long size,
 348                              bool writable, bool in_atomic)
 349 {
 350         pte_t pte;
 351         int ret = 0;
 352         unsigned long pfn;
 353         phys_addr_t addr, end;
 354         struct kvm_mmu_memory_cache pcache = {
 355                 .gfp_custom = (in_atomic) ? GFP_ATOMIC | __GFP_ACCOUNT : 0,
 356                 .gfp_zero = __GFP_ZERO,
 357         };
 358
 359         end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK;
 360         pfn = __phys_to_pfn(hpa);
 361
 362         for (addr = gpa; addr < end; addr += PAGE_SIZE) {
 363                 pte = pfn_pte(pfn, PAGE_KERNEL_IO);
 364
 365                 if (!writable)
 366                         pte = pte_wrprotect(pte);
 367
 368                 ret = kvm_mmu_topup_memory_cache(&pcache, gstage_pgd_levels);
 369                 if (ret)
 370                         goto out;
 371
 372                 spin_lock(&kvm->mmu_lock);
 373                 ret = gstage_set_pte(kvm, 0, &pcache, addr, &pte);
 374                 spin_unlock(&kvm->mmu_lock);
 375                 if (ret)
 376                         goto out;
 377
 378                 pfn++;
 379         }
 380
 381 out:
 382         kvm_mmu_free_memory_cache(&pcache);
 383         return ret;
 384 }
 385
 386 void kvm_riscv_gstage_iounmap(struct kvm *kvm, gpa_t gpa, unsigned long size)
 387 {
 388         spin_lock(&kvm->mmu_lock);
 389         gstage_unmap_range(kvm, gpa, size, false);
 390         spin_unlock(&kvm->mmu_lock);
 391 }
 392
 393 void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
 394                                              struct kvm_memory_slot *slot,
 395                                              gfn_t gfn_offset,
 396                                              unsigned long mask)
 397 {
 398         phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
 399         phys_addr_t start = (base_gfn +  __ffs(mask)) << PAGE_SHIFT;
 400         phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;
 401
 402         gstage_wp_range(kvm, start, end);
 403 }
 404
 405 void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
 406 {
 407 }
 408
 409 void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free)
 410 {
 411 }
 412
 413 void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
 414 {
 415 }
 416
 417 void kvm_arch_flush_shadow_all(struct kvm *kvm)
 418 {
 419         kvm_riscv_gstage_free_pgd(kvm);
 420 }
 421
 422 void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
 423                                    struct kvm_memory_slot *slot)
 424 {
 425         gpa_t gpa = slot->base_gfn << PAGE_SHIFT;
 426         phys_addr_t size = slot->npages << PAGE_SHIFT;
 427
 428         spin_lock(&kvm->mmu_lock);
 429         gstage_unmap_range(kvm, gpa, size, false);
 430         spin_unlock(&kvm->mmu_lock);
 431 }
 432
 433 void kvm_arch_commit_memory_region(struct kvm *kvm,
 434                                 struct kvm_memory_slot *old,
 435                                 const struct kvm_memory_slot *new,
 436                                 enum kvm_mr_change change)
 437 {
 438         /*
 439          * At this point memslot has been committed and there is an
 440          * allocated dirty_bitmap[], dirty pages will be tracked while
 441          * the memory slot is write protected.
 442          */
 443         if (change != KVM_MR_DELETE && new->flags & KVM_MEM_LOG_DIRTY_PAGES)
 444                 gstage_wp_memory_region(kvm, new->id);
 445 }
 446
 447 int kvm_arch_prepare_memory_region(struct kvm *kvm,
 448                                 const struct kvm_memory_slot *old,
 449                                 struct kvm_memory_slot *new,
 450                                 enum kvm_mr_change change)
 451 {
 452         hva_t hva, reg_end, size;
 453         gpa_t base_gpa;
 454         bool writable;
 455         int ret = 0;
 456
 457         if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
 458                         change != KVM_MR_FLAGS_ONLY)
 459                 return 0;
 460
 461         /*
 462          * Prevent userspace from creating a memory region outside of the GPA
 463          * space addressable by the KVM guest GPA space.
 464          */
 465         if ((new->base_gfn + new->npages) >=
 466             (gstage_gpa_size >> PAGE_SHIFT))
 467                 return -EFAULT;
 468
 469         hva = new->userspace_addr;
 470         size = new->npages << PAGE_SHIFT;
 471         reg_end = hva + size;
 472         base_gpa = new->base_gfn << PAGE_SHIFT;
 473         writable = !(new->flags & KVM_MEM_READONLY);
 474
 475         mmap_read_lock(current->mm);
 476
 477         /*
 478          * A memory region could potentially cover multiple VMAs, and
 479          * any holes between them, so iterate over all of them to find
 480          * out if we can map any of them right now.
 481          *
 482          *     +--------------------------------------------+
 483          * +---------------+----------------+   +----------------+
 484          * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
 485          * +---------------+----------------+   +----------------+
 486          *     |               memory region                |
 487          *     +--------------------------------------------+
 488          */
 489         do {
 490                 struct vm_area_struct *vma = find_vma(current->mm, hva);
 491                 hva_t vm_start, vm_end;
 492
 493                 if (!vma || vma->vm_start >= reg_end)
 494                         break;
 495
 496                 /*
 497                  * Mapping a read-only VMA is only allowed if the
 498                  * memory region is configured as read-only.
 499                  */
 500                 if (writable && !(vma->vm_flags & VM_WRITE)) {
 501                         ret = -EPERM;
 502                         break;
 503                 }
 504
 505                 /* Take the intersection of this VMA with the memory region */
 506                 vm_start = max(hva, vma->vm_start);
 507                 vm_end = min(reg_end, vma->vm_end);
 508
 509                 if (vma->vm_flags & VM_PFNMAP) {
 510                         gpa_t gpa = base_gpa + (vm_start - hva);
 511                         phys_addr_t pa;
 512
 513                         pa = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
 514                         pa += vm_start - vma->vm_start;
 515
 516                         /* IO region dirty page logging not allowed */
 517                         if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
 518                                 ret = -EINVAL;
 519                                 goto out;
 520                         }
 521
 522                         ret = kvm_riscv_gstage_ioremap(kvm, gpa, pa,
 523                                                        vm_end - vm_start,
 524                                                        writable, false);
 525                         if (ret)
 526                                 break;
 527                 }
 528                 hva = vm_end;
 529         } while (hva < reg_end);
 530
 531         if (change == KVM_MR_FLAGS_ONLY)
 532                 goto out;
 533
 534         if (ret)
 535                 kvm_riscv_gstage_iounmap(kvm, base_gpa, size);
 536
 537 out:
 538         mmap_read_unlock(current->mm);
 539         return ret;
 540 }
 541
 542 bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
 543 {
 544         if (!kvm->arch.pgd)
 545                 return false;
 546
 547         gstage_unmap_range(kvm, range->start << PAGE_SHIFT,
 548                            (range->end - range->start) << PAGE_SHIFT,
 549                            range->may_block);
 550         return false;
 551 }
 552
 553 bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
 554 {
 555         pte_t *ptep;
 556         u32 ptep_level = 0;
 557         u64 size = (range->end - range->start) << PAGE_SHIFT;
 558
 559         if (!kvm->arch.pgd)
 560                 return false;
 561
 562         WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
 563
 564         if (!gstage_get_leaf_entry(kvm, range->start << PAGE_SHIFT,
 565                                    &ptep, &ptep_level))
 566                 return false;
 567
 568         return ptep_test_and_clear_young(NULL, 0, ptep);
 569 }
 570
 571 bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
 572 {
 573         pte_t *ptep;
 574         u32 ptep_level = 0;
 575         u64 size = (range->end - range->start) << PAGE_SHIFT;
 576
 577         if (!kvm->arch.pgd)
 578                 return false;
 579
 580         WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
 581
 582         if (!gstage_get_leaf_entry(kvm, range->start << PAGE_SHIFT,
 583                                    &ptep, &ptep_level))
 584                 return false;
 585
 586         return pte_young(ptep_get(ptep));
 587 }
 588
 589 int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
 590                          struct kvm_memory_slot *memslot,
 591                          gpa_t gpa, unsigned long hva, bool is_write)
 592 {
 593         int ret;
 594         kvm_pfn_t hfn;
 595         bool writable;
 596         short vma_pageshift;
 597         gfn_t gfn = gpa >> PAGE_SHIFT;
 598         struct vm_area_struct *vma;
 599         struct kvm *kvm = vcpu->kvm;
 600         struct kvm_mmu_memory_cache *pcache = &vcpu->arch.mmu_page_cache;
 601         bool logging = (memslot->dirty_bitmap &&
 602                         !(memslot->flags & KVM_MEM_READONLY)) ? true : false;
 603         unsigned long vma_pagesize, mmu_seq;
 604         struct page *page;
 605
 606         /* We need minimum second+third level pages */
 607         ret = kvm_mmu_topup_memory_cache(pcache, gstage_pgd_levels);
 608         if (ret) {
 609                 kvm_err("Failed to topup G-stage cache\n");
 610                 return ret;
 611         }
 612
 613         mmap_read_lock(current->mm);
 614
 615         vma = vma_lookup(current->mm, hva);
 616         if (unlikely(!vma)) {
 617                 kvm_err("Failed to find VMA for hva 0x%lx\n", hva);
 618                 mmap_read_unlock(current->mm);
 619                 return -EFAULT;
 620         }
 621
 622         if (is_vm_hugetlb_page(vma))
 623                 vma_pageshift = huge_page_shift(hstate_vma(vma));
 624         else
 625                 vma_pageshift = PAGE_SHIFT;
 626         vma_pagesize = 1ULL << vma_pageshift;
 627         if (logging || (vma->vm_flags & VM_PFNMAP))
 628                 vma_pagesize = PAGE_SIZE;
 629
 630         if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
 631                 gfn = (gpa & huge_page_mask(hstate_vma(vma))) >> PAGE_SHIFT;
 632
 633         /*
 634          * Read mmu_invalidate_seq so that KVM can detect if the results of
 635          * vma_lookup() or __kvm_faultin_pfn() become stale prior to acquiring
 636          * kvm->mmu_lock.
 637          *
 638          * Rely on mmap_read_unlock() for an implicit smp_rmb(), which pairs
 639          * with the smp_wmb() in kvm_mmu_invalidate_end().
 640          */
 641         mmu_seq = kvm->mmu_invalidate_seq;
 642         mmap_read_unlock(current->mm);
 643
 644         if (vma_pagesize != PUD_SIZE &&
 645             vma_pagesize != PMD_SIZE &&
 646             vma_pagesize != PAGE_SIZE) {
 647                 kvm_err("Invalid VMA page size 0x%lx\n", vma_pagesize);
 648                 return -EFAULT;
 649         }
 650
 651         hfn = kvm_faultin_pfn(vcpu, gfn, is_write, &writable, &page);
 652         if (hfn == KVM_PFN_ERR_HWPOISON) {
 653                 send_sig_mceerr(BUS_MCEERR_AR, (void __user *)hva,
 654                                 vma_pageshift, current);
 655                 return 0;
 656         }
 657         if (is_error_noslot_pfn(hfn))
 658                 return -EFAULT;
 659
 660         /*
 661          * If logging is active then we allow writable pages only
 662          * for write faults.
 663          */
 664         if (logging && !is_write)
 665                 writable = false;
 666
 667         spin_lock(&kvm->mmu_lock);
 668
 669         if (mmu_invalidate_retry(kvm, mmu_seq))
 670                 goto out_unlock;
 671
 672         if (writable) {
 673                 mark_page_dirty(kvm, gfn);
 674                 ret = gstage_map_page(kvm, pcache, gpa, hfn << PAGE_SHIFT,
 675                                       vma_pagesize, false, true);
 676         } else {
 677                 ret = gstage_map_page(kvm, pcache, gpa, hfn << PAGE_SHIFT,
 678                                       vma_pagesize, true, true);
 679         }
 680
 681         if (ret)
 682                 kvm_err("Failed to map in G-stage\n");
 683
 684 out_unlock:
 685         kvm_release_faultin_page(kvm, page, ret && ret != -EEXIST, writable);
 686         spin_unlock(&kvm->mmu_lock);
 687         return ret;
 688 }
 689
 690 int kvm_riscv_gstage_alloc_pgd(struct kvm *kvm)
 691 {
 692         struct page *pgd_page;
 693
 694         if (kvm->arch.pgd != NULL) {
 695                 kvm_err("kvm_arch already initialized?\n");
 696                 return -EINVAL;
 697         }
 698
 699         pgd_page = alloc_pages(GFP_KERNEL | __GFP_ZERO,
 700                                 get_order(gstage_pgd_size));
 701         if (!pgd_page)
 702                 return -ENOMEM;
 703         kvm->arch.pgd = page_to_virt(pgd_page);
 704         kvm->arch.pgd_phys = page_to_phys(pgd_page);
 705
 706         return 0;
 707 }
 708
 709 void kvm_riscv_gstage_free_pgd(struct kvm *kvm)
 710 {
 711         void *pgd = NULL;
 712
 713         spin_lock(&kvm->mmu_lock);
 714         if (kvm->arch.pgd) {
 715                 gstage_unmap_range(kvm, 0UL, gstage_gpa_size, false);
 716                 pgd = READ_ONCE(kvm->arch.pgd);
 717                 kvm->arch.pgd = NULL;
 718                 kvm->arch.pgd_phys = 0;
 719         }
 720         spin_unlock(&kvm->mmu_lock);
 721
 722         if (pgd)
 723                 free_pages((unsigned long)pgd, get_order(gstage_pgd_size));
 724 }
 725
 726 void kvm_riscv_gstage_update_hgatp(struct kvm_vcpu *vcpu)
 727 {
 728         unsigned long hgatp = gstage_mode;
 729         struct kvm_arch *k = &vcpu->kvm->arch;
 730
 731         hgatp |= (READ_ONCE(k->vmid.vmid) << HGATP_VMID_SHIFT) & HGATP_VMID;
 732         hgatp |= (k->pgd_phys >> PAGE_SHIFT) & HGATP_PPN;
 733
 734         ncsr_write(CSR_HGATP, hgatp);
 735
 736         if (!kvm_riscv_gstage_vmid_bits())
 737                 kvm_riscv_local_hfence_gvma_all();
 738 }
 739
 740 void __init kvm_riscv_gstage_mode_detect(void)
 741 {
 742 #ifdef CONFIG_64BIT
 743         /* Try Sv57x4 G-stage mode */
 744         csr_write(CSR_HGATP, HGATP_MODE_SV57X4 << HGATP_MODE_SHIFT);
 745         if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) == HGATP_MODE_SV57X4) {
 746                 gstage_mode = (HGATP_MODE_SV57X4 << HGATP_MODE_SHIFT);
 747                 gstage_pgd_levels = 5;
 748                 goto skip_sv48x4_test;
 749         }
 750
 751         /* Try Sv48x4 G-stage mode */
 752         csr_write(CSR_HGATP, HGATP_MODE_SV48X4 << HGATP_MODE_SHIFT);
 753         if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) == HGATP_MODE_SV48X4) {
 754                 gstage_mode = (HGATP_MODE_SV48X4 << HGATP_MODE_SHIFT);
 755                 gstage_pgd_levels = 4;
 756         }
 757 skip_sv48x4_test:
 758
 759         csr_write(CSR_HGATP, 0);
 760         kvm_riscv_local_hfence_gvma_all();
 761 #endif
 762 }
 763
 764 unsigned long __init kvm_riscv_gstage_mode(void)
 765 {
 766         return gstage_mode >> HGATP_MODE_SHIFT;
 767 }
 768
 769 int kvm_riscv_gstage_gpa_bits(void)
 770 {
 771         return gstage_gpa_bits;
 772 }