/* * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * KVM/MIPS MMU handling in the KVM module. * * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved. * Authors: Sanjay Lal */ #include #include #include #include #include /* * KVM_MMU_CACHE_MIN_PAGES is the number of GPA page table translation levels * for which pages need to be cached. */ #if defined(__PAGETABLE_PMD_FOLDED) #define KVM_MMU_CACHE_MIN_PAGES 1 #else #define KVM_MMU_CACHE_MIN_PAGES 2 #endif void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu) { kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache); } /** * kvm_pgd_init() - Initialise KVM GPA page directory. * @page: Pointer to page directory (PGD) for KVM GPA. * * Initialise a KVM GPA page directory with pointers to the invalid table, i.e. * representing no mappings. This is similar to pgd_init(), however it * initialises all the page directory pointers, not just the ones corresponding * to the userland address space (since it is for the guest physical address * space rather than a virtual address space). */ static void kvm_pgd_init(void *page) { unsigned long *p, *end; unsigned long entry; #ifdef __PAGETABLE_PMD_FOLDED entry = (unsigned long)invalid_pte_table; #else entry = (unsigned long)invalid_pmd_table; #endif p = (unsigned long *)page; end = p + PTRS_PER_PGD; do { p[0] = entry; p[1] = entry; p[2] = entry; p[3] = entry; p[4] = entry; p += 8; p[-3] = entry; p[-2] = entry; p[-1] = entry; } while (p != end); } /** * kvm_pgd_alloc() - Allocate and initialise a KVM GPA page directory. * * Allocate a blank KVM GPA page directory (PGD) for representing guest physical * to host physical page mappings. * * Returns: Pointer to new KVM GPA page directory. * NULL on allocation failure. */ pgd_t *kvm_pgd_alloc(void) { pgd_t *ret; ret = (pgd_t *)__get_free_pages(GFP_KERNEL, PGD_ORDER); if (ret) kvm_pgd_init(ret); return ret; } /** * kvm_mips_walk_pgd() - Walk page table with optional allocation. * @pgd: Page directory pointer. * @addr: Address to index page table using. * @cache: MMU page cache to allocate new page tables from, or NULL. * * Walk the page tables pointed to by @pgd to find the PTE corresponding to the * address @addr. If page tables don't exist for @addr, they will be created * from the MMU cache if @cache is not NULL. * * Returns: Pointer to pte_t corresponding to @addr. * NULL if a page table doesn't exist for @addr and !@cache. * NULL if a page table allocation failed. */ static pte_t *kvm_mips_walk_pgd(pgd_t *pgd, struct kvm_mmu_memory_cache *cache, unsigned long addr) { p4d_t *p4d; pud_t *pud; pmd_t *pmd; pgd += pgd_index(addr); if (pgd_none(*pgd)) { /* Not used on MIPS yet */ BUG(); return NULL; } p4d = p4d_offset(pgd, addr); pud = pud_offset(p4d, addr); if (pud_none(*pud)) { pmd_t *new_pmd; if (!cache) return NULL; new_pmd = kvm_mmu_memory_cache_alloc(cache); pmd_init((unsigned long)new_pmd, (unsigned long)invalid_pte_table); pud_populate(NULL, pud, new_pmd); } pmd = pmd_offset(pud, addr); if (pmd_none(*pmd)) { pte_t *new_pte; if (!cache) return NULL; new_pte = kvm_mmu_memory_cache_alloc(cache); clear_page(new_pte); pmd_populate_kernel(NULL, pmd, new_pte); } return pte_offset_kernel(pmd, addr); } /* Caller must hold kvm->mm_lock */ static pte_t *kvm_mips_pte_for_gpa(struct kvm *kvm, struct kvm_mmu_memory_cache *cache, unsigned long addr) { return kvm_mips_walk_pgd(kvm->arch.gpa_mm.pgd, cache, addr); } /* * kvm_mips_flush_gpa_{pte,pmd,pud,pgd,pt}. * Flush a range of guest physical address space from the VM's GPA page tables. */ static bool kvm_mips_flush_gpa_pte(pte_t *pte, unsigned long start_gpa, unsigned long end_gpa) { int i_min = pte_index(start_gpa); int i_max = pte_index(end_gpa); bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PTE - 1); int i; for (i = i_min; i <= i_max; ++i) { if (!pte_present(pte[i])) continue; set_pte(pte + i, __pte(0)); } return safe_to_remove; } static bool kvm_mips_flush_gpa_pmd(pmd_t *pmd, unsigned long start_gpa, unsigned long end_gpa) { pte_t *pte; unsigned long end = ~0ul; int i_min = pmd_index(start_gpa); int i_max = pmd_index(end_gpa); bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PMD - 1); int i; for (i = i_min; i <= i_max; ++i, start_gpa = 0) { if (!pmd_present(pmd[i])) continue; pte = pte_offset_kernel(pmd + i, 0); if (i == i_max) end = end_gpa; if (kvm_mips_flush_gpa_pte(pte, start_gpa, end)) { pmd_clear(pmd + i); pte_free_kernel(NULL, pte); } else { safe_to_remove = false; } } return safe_to_remove; } static bool kvm_mips_flush_gpa_pud(pud_t *pud, unsigned long start_gpa, unsigned long end_gpa) { pmd_t *pmd; unsigned long end = ~0ul; int i_min = pud_index(start_gpa); int i_max = pud_index(end_gpa); bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PUD - 1); int i; for (i = i_min; i <= i_max; ++i, start_gpa = 0) { if (!pud_present(pud[i])) continue; pmd = pmd_offset(pud + i, 0); if (i == i_max) end = end_gpa; if (kvm_mips_flush_gpa_pmd(pmd, start_gpa, end)) { pud_clear(pud + i); pmd_free(NULL, pmd); } else { safe_to_remove = false; } } return safe_to_remove; } static bool kvm_mips_flush_gpa_pgd(pgd_t *pgd, unsigned long start_gpa, unsigned long end_gpa) { p4d_t *p4d; pud_t *pud; unsigned long end = ~0ul; int i_min = pgd_index(start_gpa); int i_max = pgd_index(end_gpa); bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PGD - 1); int i; for (i = i_min; i <= i_max; ++i, start_gpa = 0) { if (!pgd_present(pgd[i])) continue; p4d = p4d_offset(pgd, 0); pud = pud_offset(p4d + i, 0); if (i == i_max) end = end_gpa; if (kvm_mips_flush_gpa_pud(pud, start_gpa, end)) { pgd_clear(pgd + i); pud_free(NULL, pud); } else { safe_to_remove = false; } } return safe_to_remove; } /** * kvm_mips_flush_gpa_pt() - Flush a range of guest physical addresses. * @kvm: KVM pointer. * @start_gfn: Guest frame number of first page in GPA range to flush. * @end_gfn: Guest frame number of last page in GPA range to flush. * * Flushes a range of GPA mappings from the GPA page tables. * * The caller must hold the @kvm->mmu_lock spinlock. * * Returns: Whether its safe to remove the top level page directory because * all lower levels have been removed. */ bool kvm_mips_flush_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn) { return kvm_mips_flush_gpa_pgd(kvm->arch.gpa_mm.pgd, start_gfn << PAGE_SHIFT, end_gfn << PAGE_SHIFT); } #define BUILD_PTE_RANGE_OP(name, op) \ static int kvm_mips_##name##_pte(pte_t *pte, unsigned long start, \ unsigned long end) \ { \ int ret = 0; \ int i_min = pte_index(start); \ int i_max = pte_index(end); \ int i; \ pte_t old, new; \ \ for (i = i_min; i <= i_max; ++i) { \ if (!pte_present(pte[i])) \ continue; \ \ old = pte[i]; \ new = op(old); \ if (pte_val(new) == pte_val(old)) \ continue; \ set_pte(pte + i, new); \ ret = 1; \ } \ return ret; \ } \ \ /* returns true if anything was done */ \ static int kvm_mips_##name##_pmd(pmd_t *pmd, unsigned long start, \ unsigned long end) \ { \ int ret = 0; \ pte_t *pte; \ unsigned long cur_end = ~0ul; \ int i_min = pmd_index(start); \ int i_max = pmd_index(end); \ int i; \ \ for (i = i_min; i <= i_max; ++i, start = 0) { \ if (!pmd_present(pmd[i])) \ continue; \ \ pte = pte_offset_kernel(pmd + i, 0); \ if (i == i_max) \ cur_end = end; \ \ ret |= kvm_mips_##name##_pte(pte, start, cur_end); \ } \ return ret; \ } \ \ static int kvm_mips_##name##_pud(pud_t *pud, unsigned long start, \ unsigned long end) \ { \ int ret = 0; \ pmd_t *pmd; \ unsigned long cur_end = ~0ul; \ int i_min = pud_index(start); \ int i_max = pud_index(end); \ int i; \ \ for (i = i_min; i <= i_max; ++i, start = 0) { \ if (!pud_present(pud[i])) \ continue; \ \ pmd = pmd_offset(pud + i, 0); \ if (i == i_max) \ cur_end = end; \ \ ret |= kvm_mips_##name##_pmd(pmd, start, cur_end); \ } \ return ret; \ } \ \ static int kvm_mips_##name##_pgd(pgd_t *pgd, unsigned long start, \ unsigned long end) \ { \ int ret = 0; \ p4d_t *p4d; \ pud_t *pud; \ unsigned long cur_end = ~0ul; \ int i_min = pgd_index(start); \ int i_max = pgd_index(end); \ int i; \ \ for (i = i_min; i <= i_max; ++i, start = 0) { \ if (!pgd_present(pgd[i])) \ continue; \ \ p4d = p4d_offset(pgd, 0); \ pud = pud_offset(p4d + i, 0); \ if (i == i_max) \ cur_end = end; \ \ ret |= kvm_mips_##name##_pud(pud, start, cur_end); \ } \ return ret; \ } /* * kvm_mips_mkclean_gpa_pt. * Mark a range of guest physical address space clean (writes fault) in the VM's * GPA page table to allow dirty page tracking. */ BUILD_PTE_RANGE_OP(mkclean, pte_mkclean) /** * kvm_mips_mkclean_gpa_pt() - Make a range of guest physical addresses clean. * @kvm: KVM pointer. * @start_gfn: Guest frame number of first page in GPA range to flush. * @end_gfn: Guest frame number of last page in GPA range to flush. * * Make a range of GPA mappings clean so that guest writes will fault and * trigger dirty page logging. * * The caller must hold the @kvm->mmu_lock spinlock. * * Returns: Whether any GPA mappings were modified, which would require * derived mappings (GVA page tables & TLB enties) to be * invalidated. */ int kvm_mips_mkclean_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn) { return kvm_mips_mkclean_pgd(kvm->arch.gpa_mm.pgd, start_gfn << PAGE_SHIFT, end_gfn << PAGE_SHIFT); } /** * kvm_arch_mmu_enable_log_dirty_pt_masked() - write protect dirty pages * @kvm: The KVM pointer * @slot: The memory slot associated with mask * @gfn_offset: The gfn offset in memory slot * @mask: The mask of dirty pages at offset 'gfn_offset' in this memory * slot to be write protected * * Walks bits set in mask write protects the associated pte's. Caller must * acquire @kvm->mmu_lock. */ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn_offset, unsigned long mask) { gfn_t base_gfn = slot->base_gfn + gfn_offset; gfn_t start = base_gfn + __ffs(mask); gfn_t end = base_gfn + __fls(mask); kvm_mips_mkclean_gpa_pt(kvm, start, end); } /* * kvm_mips_mkold_gpa_pt. * Mark a range of guest physical address space old (all accesses fault) in the * VM's GPA page table to allow detection of commonly used pages. */ BUILD_PTE_RANGE_OP(mkold, pte_mkold) static int kvm_mips_mkold_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn) { return kvm_mips_mkold_pgd(kvm->arch.gpa_mm.pgd, start_gfn << PAGE_SHIFT, end_gfn << PAGE_SHIFT); } static int handle_hva_to_gpa(struct kvm *kvm, unsigned long start, unsigned long end, int (*handler)(struct kvm *kvm, gfn_t gfn, gpa_t gfn_end, struct kvm_memory_slot *memslot, void *data), void *data) { struct kvm_memslots *slots; struct kvm_memory_slot *memslot; int ret = 0; slots = kvm_memslots(kvm); /* we only care about the pages that the guest sees */ kvm_for_each_memslot(memslot, slots) { unsigned long hva_start, hva_end; gfn_t gfn, gfn_end; hva_start = max(start, memslot->userspace_addr); hva_end = min(end, memslot->userspace_addr + (memslot->npages << PAGE_SHIFT)); if (hva_start >= hva_end) continue; /* * {gfn(page) | page intersects with [hva_start, hva_end)} = * {gfn_start, gfn_start+1, ..., gfn_end-1}. */ gfn = hva_to_gfn_memslot(hva_start, memslot); gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot); ret |= handler(kvm, gfn, gfn_end, memslot, data); } return ret; } static int kvm_unmap_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end, struct kvm_memory_slot *memslot, void *data) { kvm_mips_flush_gpa_pt(kvm, gfn, gfn_end); return 1; } int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end, unsigned flags) { handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL); kvm_mips_callbacks->flush_shadow_all(kvm); return 0; } static int kvm_set_spte_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end, struct kvm_memory_slot *memslot, void *data) { gpa_t gpa = gfn << PAGE_SHIFT; pte_t hva_pte = *(pte_t *)data; pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa); pte_t old_pte; if (!gpa_pte) return 0; /* Mapping may need adjusting depending on memslot flags */ old_pte = *gpa_pte; if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES && !pte_dirty(old_pte)) hva_pte = pte_mkclean(hva_pte); else if (memslot->flags & KVM_MEM_READONLY) hva_pte = pte_wrprotect(hva_pte); set_pte(gpa_pte, hva_pte); /* Replacing an absent or old page doesn't need flushes */ if (!pte_present(old_pte) || !pte_young(old_pte)) return 0; /* Pages swapped, aged, moved, or cleaned require flushes */ return !pte_present(hva_pte) || !pte_young(hva_pte) || pte_pfn(old_pte) != pte_pfn(hva_pte) || (pte_dirty(old_pte) && !pte_dirty(hva_pte)); } int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte) { unsigned long end = hva + PAGE_SIZE; int ret; ret = handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &pte); if (ret) kvm_mips_callbacks->flush_shadow_all(kvm); return 0; } static int kvm_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end, struct kvm_memory_slot *memslot, void *data) { return kvm_mips_mkold_gpa_pt(kvm, gfn, gfn_end); } static int kvm_test_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end, struct kvm_memory_slot *memslot, void *data) { gpa_t gpa = gfn << PAGE_SHIFT; pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa); if (!gpa_pte) return 0; return pte_young(*gpa_pte); } int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end) { return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL); } int kvm_test_age_hva(struct kvm *kvm, unsigned long hva) { return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL); } /** * _kvm_mips_map_page_fast() - Fast path GPA fault handler. * @vcpu: VCPU pointer. * @gpa: Guest physical address of fault. * @write_fault: Whether the fault was due to a write. * @out_entry: New PTE for @gpa (written on success unless NULL). * @out_buddy: New PTE for @gpa's buddy (written on success unless * NULL). * * Perform fast path GPA fault handling, doing all that can be done without * calling into KVM. This handles marking old pages young (for idle page * tracking), and dirtying of clean pages (for dirty page logging). * * Returns: 0 on success, in which case we can update derived mappings and * resume guest execution. * -EFAULT on failure due to absent GPA mapping or write to * read-only page, in which case KVM must be consulted. */ static int _kvm_mips_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa, bool write_fault, pte_t *out_entry, pte_t *out_buddy) { struct kvm *kvm = vcpu->kvm; gfn_t gfn = gpa >> PAGE_SHIFT; pte_t *ptep; kvm_pfn_t pfn = 0; /* silence bogus GCC warning */ bool pfn_valid = false; int ret = 0; spin_lock(&kvm->mmu_lock); /* Fast path - just check GPA page table for an existing entry */ ptep = kvm_mips_pte_for_gpa(kvm, NULL, gpa); if (!ptep || !pte_present(*ptep)) { ret = -EFAULT; goto out; } /* Track access to pages marked old */ if (!pte_young(*ptep)) { set_pte(ptep, pte_mkyoung(*ptep)); pfn = pte_pfn(*ptep); pfn_valid = true; /* call kvm_set_pfn_accessed() after unlock */ } if (write_fault && !pte_dirty(*ptep)) { if (!pte_write(*ptep)) { ret = -EFAULT; goto out; } /* Track dirtying of writeable pages */ set_pte(ptep, pte_mkdirty(*ptep)); pfn = pte_pfn(*ptep); mark_page_dirty(kvm, gfn); kvm_set_pfn_dirty(pfn); } if (out_entry) *out_entry = *ptep; if (out_buddy) *out_buddy = *ptep_buddy(ptep); out: spin_unlock(&kvm->mmu_lock); if (pfn_valid) kvm_set_pfn_accessed(pfn); return ret; } /** * kvm_mips_map_page() - Map a guest physical page. * @vcpu: VCPU pointer. * @gpa: Guest physical address of fault. * @write_fault: Whether the fault was due to a write. * @out_entry: New PTE for @gpa (written on success unless NULL). * @out_buddy: New PTE for @gpa's buddy (written on success unless * NULL). * * Handle GPA faults by creating a new GPA mapping (or updating an existing * one). * * This takes care of marking pages young or dirty (idle/dirty page tracking), * asking KVM for the corresponding PFN, and creating a mapping in the GPA page * tables. Derived mappings (GVA page tables and TLBs) must be handled by the * caller. * * Returns: 0 on success, in which case the caller may use the @out_entry * and @out_buddy PTEs to update derived mappings and resume guest * execution. * -EFAULT if there is no memory region at @gpa or a write was * attempted to a read-only memory region. This is usually handled * as an MMIO access. */ static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa, bool write_fault, pte_t *out_entry, pte_t *out_buddy) { struct kvm *kvm = vcpu->kvm; struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; gfn_t gfn = gpa >> PAGE_SHIFT; int srcu_idx, err; kvm_pfn_t pfn; pte_t *ptep, entry; bool writeable; unsigned long prot_bits; unsigned long mmu_seq; /* Try the fast path to handle old / clean pages */ srcu_idx = srcu_read_lock(&kvm->srcu); err = _kvm_mips_map_page_fast(vcpu, gpa, write_fault, out_entry, out_buddy); if (!err) goto out; /* We need a minimum of cached pages ready for page table creation */ err = kvm_mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES); if (err) goto out; retry: /* * Used to check for invalidations in progress, of the pfn that is * returned by pfn_to_pfn_prot below. */ mmu_seq = kvm->mmu_notifier_seq; /* * Ensure the read of mmu_notifier_seq isn't reordered with PTE reads in * gfn_to_pfn_prot() (which calls get_user_pages()), so that we don't * risk the page we get a reference to getting unmapped before we have a * chance to grab the mmu_lock without mmu_notifier_retry() noticing. * * This smp_rmb() pairs with the effective smp_wmb() of the combination * of the pte_unmap_unlock() after the PTE is zapped, and the * spin_lock() in kvm_mmu_notifier_invalidate_() before * mmu_notifier_seq is incremented. */ smp_rmb(); /* Slow path - ask KVM core whether we can access this GPA */ pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writeable); if (is_error_noslot_pfn(pfn)) { err = -EFAULT; goto out; } spin_lock(&kvm->mmu_lock); /* Check if an invalidation has taken place since we got pfn */ if (mmu_notifier_retry(kvm, mmu_seq)) { /* * This can happen when mappings are changed asynchronously, but * also synchronously if a COW is triggered by * gfn_to_pfn_prot(). */ spin_unlock(&kvm->mmu_lock); kvm_release_pfn_clean(pfn); goto retry; } /* Ensure page tables are allocated */ ptep = kvm_mips_pte_for_gpa(kvm, memcache, gpa); /* Set up the PTE */ prot_bits = _PAGE_PRESENT | __READABLE | _page_cachable_default; if (writeable) { prot_bits |= _PAGE_WRITE; if (write_fault) { prot_bits |= __WRITEABLE; mark_page_dirty(kvm, gfn); kvm_set_pfn_dirty(pfn); } } entry = pfn_pte(pfn, __pgprot(prot_bits)); /* Write the PTE */ set_pte(ptep, entry); err = 0; if (out_entry) *out_entry = *ptep; if (out_buddy) *out_buddy = *ptep_buddy(ptep); spin_unlock(&kvm->mmu_lock); kvm_release_pfn_clean(pfn); kvm_set_pfn_accessed(pfn); out: srcu_read_unlock(&kvm->srcu, srcu_idx); return err; } static pte_t *kvm_trap_emul_pte_for_gva(struct kvm_vcpu *vcpu, unsigned long addr) { struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; pgd_t *pgdp; int ret; /* We need a minimum of cached pages ready for page table creation */ ret = kvm_mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES); if (ret) return NULL; if (KVM_GUEST_KERNEL_MODE(vcpu)) pgdp = vcpu->arch.guest_kernel_mm.pgd; else pgdp = vcpu->arch.guest_user_mm.pgd; return kvm_mips_walk_pgd(pgdp, memcache, addr); } void kvm_trap_emul_invalidate_gva(struct kvm_vcpu *vcpu, unsigned long addr, bool user) { pgd_t *pgdp; pte_t *ptep; addr &= PAGE_MASK << 1; pgdp = vcpu->arch.guest_kernel_mm.pgd; ptep = kvm_mips_walk_pgd(pgdp, NULL, addr); if (ptep) { ptep[0] = pfn_pte(0, __pgprot(0)); ptep[1] = pfn_pte(0, __pgprot(0)); } if (user) { pgdp = vcpu->arch.guest_user_mm.pgd; ptep = kvm_mips_walk_pgd(pgdp, NULL, addr); if (ptep) { ptep[0] = pfn_pte(0, __pgprot(0)); ptep[1] = pfn_pte(0, __pgprot(0)); } } } /* * kvm_mips_flush_gva_{pte,pmd,pud,pgd,pt}. * Flush a range of guest physical address space from the VM's GPA page tables. */ static bool kvm_mips_flush_gva_pte(pte_t *pte, unsigned long start_gva, unsigned long end_gva) { int i_min = pte_index(start_gva); int i_max = pte_index(end_gva); bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PTE - 1); int i; /* * There's no freeing to do, so there's no point clearing individual * entries unless only part of the last level page table needs flushing. */ if (safe_to_remove) return true; for (i = i_min; i <= i_max; ++i) { if (!pte_present(pte[i])) continue; set_pte(pte + i, __pte(0)); } return false; } static bool kvm_mips_flush_gva_pmd(pmd_t *pmd, unsigned long start_gva, unsigned long end_gva) { pte_t *pte; unsigned long end = ~0ul; int i_min = pmd_index(start_gva); int i_max = pmd_index(end_gva); bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PMD - 1); int i; for (i = i_min; i <= i_max; ++i, start_gva = 0) { if (!pmd_present(pmd[i])) continue; pte = pte_offset_kernel(pmd + i, 0); if (i == i_max) end = end_gva; if (kvm_mips_flush_gva_pte(pte, start_gva, end)) { pmd_clear(pmd + i); pte_free_kernel(NULL, pte); } else { safe_to_remove = false; } } return safe_to_remove; } static bool kvm_mips_flush_gva_pud(pud_t *pud, unsigned long start_gva, unsigned long end_gva) { pmd_t *pmd; unsigned long end = ~0ul; int i_min = pud_index(start_gva); int i_max = pud_index(end_gva); bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PUD - 1); int i; for (i = i_min; i <= i_max; ++i, start_gva = 0) { if (!pud_present(pud[i])) continue; pmd = pmd_offset(pud + i, 0); if (i == i_max) end = end_gva; if (kvm_mips_flush_gva_pmd(pmd, start_gva, end)) { pud_clear(pud + i); pmd_free(NULL, pmd); } else { safe_to_remove = false; } } return safe_to_remove; } static bool kvm_mips_flush_gva_pgd(pgd_t *pgd, unsigned long start_gva, unsigned long end_gva) { p4d_t *p4d; pud_t *pud; unsigned long end = ~0ul; int i_min = pgd_index(start_gva); int i_max = pgd_index(end_gva); bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PGD - 1); int i; for (i = i_min; i <= i_max; ++i, start_gva = 0) { if (!pgd_present(pgd[i])) continue; p4d = p4d_offset(pgd, 0); pud = pud_offset(p4d + i, 0); if (i == i_max) end = end_gva; if (kvm_mips_flush_gva_pud(pud, start_gva, end)) { pgd_clear(pgd + i); pud_free(NULL, pud); } else { safe_to_remove = false; } } return safe_to_remove; } void kvm_mips_flush_gva_pt(pgd_t *pgd, enum kvm_mips_flush flags) { if (flags & KMF_GPA) { /* all of guest virtual address space could be affected */ if (flags & KMF_KERN) /* useg, kseg0, seg2/3 */ kvm_mips_flush_gva_pgd(pgd, 0, 0x7fffffff); else /* useg */ kvm_mips_flush_gva_pgd(pgd, 0, 0x3fffffff); } else { /* useg */ kvm_mips_flush_gva_pgd(pgd, 0, 0x3fffffff); /* kseg2/3 */ if (flags & KMF_KERN) kvm_mips_flush_gva_pgd(pgd, 0x60000000, 0x7fffffff); } } static pte_t kvm_mips_gpa_pte_to_gva_unmapped(pte_t pte) { /* * Don't leak writeable but clean entries from GPA page tables. We don't * want the normal Linux tlbmod handler to handle dirtying when KVM * accesses guest memory. */ if (!pte_dirty(pte)) pte = pte_wrprotect(pte); return pte; } static pte_t kvm_mips_gpa_pte_to_gva_mapped(pte_t pte, long entrylo) { /* Guest EntryLo overrides host EntryLo */ if (!(entrylo & ENTRYLO_D)) pte = pte_mkclean(pte); return kvm_mips_gpa_pte_to_gva_unmapped(pte); } #ifdef CONFIG_KVM_MIPS_VZ int kvm_mips_handle_vz_root_tlb_fault(unsigned long badvaddr, struct kvm_vcpu *vcpu, bool write_fault) { int ret; ret = kvm_mips_map_page(vcpu, badvaddr, write_fault, NULL, NULL); if (ret) return ret; /* Invalidate this entry in the TLB */ return kvm_vz_host_tlb_inv(vcpu, badvaddr); } #endif /* XXXKYMA: Must be called with interrupts disabled */ int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr, struct kvm_vcpu *vcpu, bool write_fault) { unsigned long gpa; pte_t pte_gpa[2], *ptep_gva; int idx; if (KVM_GUEST_KSEGX(badvaddr) != KVM_GUEST_KSEG0) { kvm_err("%s: Invalid BadVaddr: %#lx\n", __func__, badvaddr); kvm_mips_dump_host_tlbs(); return -1; } /* Get the GPA page table entry */ gpa = KVM_GUEST_CPHYSADDR(badvaddr); idx = (badvaddr >> PAGE_SHIFT) & 1; if (kvm_mips_map_page(vcpu, gpa, write_fault, &pte_gpa[idx], &pte_gpa[!idx]) < 0) return -1; /* Get the GVA page table entry */ ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, badvaddr & ~PAGE_SIZE); if (!ptep_gva) { kvm_err("No ptep for gva %lx\n", badvaddr); return -1; } /* Copy a pair of entries from GPA page table to GVA page table */ ptep_gva[0] = kvm_mips_gpa_pte_to_gva_unmapped(pte_gpa[0]); ptep_gva[1] = kvm_mips_gpa_pte_to_gva_unmapped(pte_gpa[1]); /* Invalidate this entry in the TLB, guest kernel ASID only */ kvm_mips_host_tlb_inv(vcpu, badvaddr, false, true); return 0; } int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu, struct kvm_mips_tlb *tlb, unsigned long gva, bool write_fault) { struct kvm *kvm = vcpu->kvm; long tlb_lo[2]; pte_t pte_gpa[2], *ptep_buddy, *ptep_gva; unsigned int idx = TLB_LO_IDX(*tlb, gva); bool kernel = KVM_GUEST_KERNEL_MODE(vcpu); tlb_lo[0] = tlb->tlb_lo[0]; tlb_lo[1] = tlb->tlb_lo[1]; /* * The commpage address must not be mapped to anything else if the guest * TLB contains entries nearby, or commpage accesses will break. */ if (!((gva ^ KVM_GUEST_COMMPAGE_ADDR) & VPN2_MASK & (PAGE_MASK << 1))) tlb_lo[TLB_LO_IDX(*tlb, KVM_GUEST_COMMPAGE_ADDR)] = 0; /* Get the GPA page table entry */ if (kvm_mips_map_page(vcpu, mips3_tlbpfn_to_paddr(tlb_lo[idx]), write_fault, &pte_gpa[idx], NULL) < 0) return -1; /* And its GVA buddy's GPA page table entry if it also exists */ pte_gpa[!idx] = pfn_pte(0, __pgprot(0)); if (tlb_lo[!idx] & ENTRYLO_V) { spin_lock(&kvm->mmu_lock); ptep_buddy = kvm_mips_pte_for_gpa(kvm, NULL, mips3_tlbpfn_to_paddr(tlb_lo[!idx])); if (ptep_buddy) pte_gpa[!idx] = *ptep_buddy; spin_unlock(&kvm->mmu_lock); } /* Get the GVA page table entry pair */ ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, gva & ~PAGE_SIZE); if (!ptep_gva) { kvm_err("No ptep for gva %lx\n", gva); return -1; } /* Copy a pair of entries from GPA page table to GVA page table */ ptep_gva[0] = kvm_mips_gpa_pte_to_gva_mapped(pte_gpa[0], tlb_lo[0]); ptep_gva[1] = kvm_mips_gpa_pte_to_gva_mapped(pte_gpa[1], tlb_lo[1]); /* Invalidate this entry in the TLB, current guest mode ASID only */ kvm_mips_host_tlb_inv(vcpu, gva, !kernel, kernel); kvm_debug("@ %#lx tlb_lo0: 0x%08lx tlb_lo1: 0x%08lx\n", vcpu->arch.pc, tlb->tlb_lo[0], tlb->tlb_lo[1]); return 0; } int kvm_mips_handle_commpage_tlb_fault(unsigned long badvaddr, struct kvm_vcpu *vcpu) { kvm_pfn_t pfn; pte_t *ptep; ptep = kvm_trap_emul_pte_for_gva(vcpu, badvaddr); if (!ptep) { kvm_err("No ptep for commpage %lx\n", badvaddr); return -1; } pfn = PFN_DOWN(virt_to_phys(vcpu->arch.kseg0_commpage)); /* Also set valid and dirty, so refill handler doesn't have to */ *ptep = pte_mkyoung(pte_mkdirty(pfn_pte(pfn, PAGE_SHARED))); /* Invalidate this entry in the TLB, guest kernel ASID only */ kvm_mips_host_tlb_inv(vcpu, badvaddr, false, true); return 0; } /** * kvm_mips_migrate_count() - Migrate timer. * @vcpu: Virtual CPU. * * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it * if it was running prior to being cancelled. * * Must be called when the VCPU is migrated to a different CPU to ensure that * timer expiry during guest execution interrupts the guest and causes the * interrupt to be delivered in a timely manner. */ static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu) { if (hrtimer_cancel(&vcpu->arch.comparecount_timer)) hrtimer_restart(&vcpu->arch.comparecount_timer); } /* Restore ASID once we are scheduled back after preemption */ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { unsigned long flags; kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu); local_irq_save(flags); vcpu->cpu = cpu; if (vcpu->arch.last_sched_cpu != cpu) { kvm_debug("[%d->%d]KVM VCPU[%d] switch\n", vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id); /* * Migrate the timer interrupt to the current CPU so that it * always interrupts the guest and synchronously triggers a * guest timer interrupt. */ kvm_mips_migrate_count(vcpu); } /* restore guest state to registers */ kvm_mips_callbacks->vcpu_load(vcpu, cpu); local_irq_restore(flags); } /* ASID can change if another task is scheduled during preemption */ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { unsigned long flags; int cpu; local_irq_save(flags); cpu = smp_processor_id(); vcpu->arch.last_sched_cpu = cpu; vcpu->cpu = -1; /* save guest state in registers */ kvm_mips_callbacks->vcpu_put(vcpu, cpu); local_irq_restore(flags); } /** * kvm_trap_emul_gva_fault() - Safely attempt to handle a GVA access fault. * @vcpu: Virtual CPU. * @gva: Guest virtual address to be accessed. * @write: True if write attempted (must be dirtied and made writable). * * Safely attempt to handle a GVA fault, mapping GVA pages if necessary, and * dirtying the page if @write so that guest instructions can be modified. * * Returns: KVM_MIPS_MAPPED on success. * KVM_MIPS_GVA if bad guest virtual address. * KVM_MIPS_GPA if bad guest physical address. * KVM_MIPS_TLB if guest TLB not present. * KVM_MIPS_TLBINV if guest TLB present but not valid. * KVM_MIPS_TLBMOD if guest TLB read only. */ enum kvm_mips_fault_result kvm_trap_emul_gva_fault(struct kvm_vcpu *vcpu, unsigned long gva, bool write) { struct mips_coproc *cop0 = vcpu->arch.cop0; struct kvm_mips_tlb *tlb; int index; if (KVM_GUEST_KSEGX(gva) == KVM_GUEST_KSEG0) { if (kvm_mips_handle_kseg0_tlb_fault(gva, vcpu, write) < 0) return KVM_MIPS_GPA; } else if ((KVM_GUEST_KSEGX(gva) < KVM_GUEST_KSEG0) || KVM_GUEST_KSEGX(gva) == KVM_GUEST_KSEG23) { /* Address should be in the guest TLB */ index = kvm_mips_guest_tlb_lookup(vcpu, (gva & VPN2_MASK) | (kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID)); if (index < 0) return KVM_MIPS_TLB; tlb = &vcpu->arch.guest_tlb[index]; /* Entry should be valid, and dirty for writes */ if (!TLB_IS_VALID(*tlb, gva)) return KVM_MIPS_TLBINV; if (write && !TLB_IS_DIRTY(*tlb, gva)) return KVM_MIPS_TLBMOD; if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb, gva, write)) return KVM_MIPS_GPA; } else { return KVM_MIPS_GVA; } return KVM_MIPS_MAPPED; } int kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu, u32 *out) { int err; if (WARN(IS_ENABLED(CONFIG_KVM_MIPS_VZ), "Expect BadInstr/BadInstrP registers to be used with VZ\n")) return -EINVAL; retry: kvm_trap_emul_gva_lockless_begin(vcpu); err = get_user(*out, opc); kvm_trap_emul_gva_lockless_end(vcpu); if (unlikely(err)) { /* * Try to handle the fault, maybe we just raced with a GVA * invalidation. */ err = kvm_trap_emul_gva_fault(vcpu, (unsigned long)opc, false); if (unlikely(err)) { kvm_err("%s: illegal address: %p\n", __func__, opc); return -EFAULT; } /* Hopefully it'll work now */ goto retry; } return 0; }