/* * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License, version 2, as * published by the Free Software Foundation. * * Copyright 2016 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> */ #include <linux/types.h> #include <linux/string.h> #include <linux/kvm.h> #include <linux/kvm_host.h> #include <asm/kvm_ppc.h> #include <asm/kvm_book3s.h> #include <asm/page.h> #include <asm/mmu.h> #include <asm/pgtable.h> #include <asm/pgalloc.h> #include <asm/pte-walk.h> /* * Supported radix tree geometry. * Like p9, we support either 5 or 9 bits at the first (lowest) level, * for a page size of 64k or 4k. */ static int p9_supported_radix_bits[4] = { 5, 9, 9, 13 }; int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr, struct kvmppc_pte *gpte, bool data, bool iswrite) { struct kvm *kvm = vcpu->kvm; u32 pid; int ret, level, ps; __be64 prte, rpte; unsigned long ptbl; unsigned long root, pte, index; unsigned long rts, bits, offset; unsigned long gpa; unsigned long proc_tbl_size; /* Work out effective PID */ switch (eaddr >> 62) { case 0: pid = vcpu->arch.pid; break; case 3: pid = 0; break; default: return -EINVAL; } proc_tbl_size = 1 << ((kvm->arch.process_table & PRTS_MASK) + 12); if (pid * 16 >= proc_tbl_size) return -EINVAL; /* Read partition table to find root of tree for effective PID */ ptbl = (kvm->arch.process_table & PRTB_MASK) + (pid * 16); ret = kvm_read_guest(kvm, ptbl, &prte, sizeof(prte)); if (ret) return ret; root = be64_to_cpu(prte); rts = ((root & RTS1_MASK) >> (RTS1_SHIFT - 3)) | ((root & RTS2_MASK) >> RTS2_SHIFT); bits = root & RPDS_MASK; root = root & RPDB_MASK; /* P9 DD1 interprets RTS (radix tree size) differently */ offset = rts + 31; if (cpu_has_feature(CPU_FTR_POWER9_DD1)) offset -= 3; /* current implementations only support 52-bit space */ if (offset != 52) return -EINVAL; for (level = 3; level >= 0; --level) { if (level && bits != p9_supported_radix_bits[level]) return -EINVAL; if (level == 0 && !(bits == 5 || bits == 9)) return -EINVAL; offset -= bits; index = (eaddr >> offset) & ((1UL << bits) - 1); /* check that low bits of page table base are zero */ if (root & ((1UL << (bits + 3)) - 1)) return -EINVAL; ret = kvm_read_guest(kvm, root + index * 8, &rpte, sizeof(rpte)); if (ret) return ret; pte = __be64_to_cpu(rpte); if (!(pte & _PAGE_PRESENT)) return -ENOENT; if (pte & _PAGE_PTE) break; bits = pte & 0x1f; root = pte & 0x0fffffffffffff00ul; } /* need a leaf at lowest level; 512GB pages not supported */ if (level < 0 || level == 3) return -EINVAL; /* offset is now log base 2 of the page size */ gpa = pte & 0x01fffffffffff000ul; if (gpa & ((1ul << offset) - 1)) return -EINVAL; gpa += eaddr & ((1ul << offset) - 1); for (ps = MMU_PAGE_4K; ps < MMU_PAGE_COUNT; ++ps) if (offset == mmu_psize_defs[ps].shift) break; gpte->page_size = ps; gpte->eaddr = eaddr; gpte->raddr = gpa; /* Work out permissions */ gpte->may_read = !!(pte & _PAGE_READ); gpte->may_write = !!(pte & _PAGE_WRITE); gpte->may_execute = !!(pte & _PAGE_EXEC); if (kvmppc_get_msr(vcpu) & MSR_PR) { if (pte & _PAGE_PRIVILEGED) { gpte->may_read = 0; gpte->may_write = 0; gpte->may_execute = 0; } } else { if (!(pte & _PAGE_PRIVILEGED)) { /* Check AMR/IAMR to see if strict mode is in force */ if (vcpu->arch.amr & (1ul << 62)) gpte->may_read = 0; if (vcpu->arch.amr & (1ul << 63)) gpte->may_write = 0; if (vcpu->arch.iamr & (1ul << 62)) gpte->may_execute = 0; } } return 0; } #ifdef CONFIG_PPC_64K_PAGES #define MMU_BASE_PSIZE MMU_PAGE_64K #else #define MMU_BASE_PSIZE MMU_PAGE_4K #endif static void kvmppc_radix_tlbie_page(struct kvm *kvm, unsigned long addr, unsigned int pshift) { int psize = MMU_BASE_PSIZE; if (pshift >= PMD_SHIFT) psize = MMU_PAGE_2M; addr &= ~0xfffUL; addr |= mmu_psize_defs[psize].ap << 5; asm volatile("ptesync": : :"memory"); asm volatile(PPC_TLBIE_5(%0, %1, 0, 0, 1) : : "r" (addr), "r" (kvm->arch.lpid) : "memory"); asm volatile("ptesync": : :"memory"); } unsigned long kvmppc_radix_update_pte(struct kvm *kvm, pte_t *ptep, unsigned long clr, unsigned long set, unsigned long addr, unsigned int shift) { unsigned long old = 0; if (!(clr & _PAGE_PRESENT) && cpu_has_feature(CPU_FTR_POWER9_DD1) && pte_present(*ptep)) { /* have to invalidate it first */ old = __radix_pte_update(ptep, _PAGE_PRESENT, 0); kvmppc_radix_tlbie_page(kvm, addr, shift); set |= _PAGE_PRESENT; old &= _PAGE_PRESENT; } return __radix_pte_update(ptep, clr, set) | old; } void kvmppc_radix_set_pte_at(struct kvm *kvm, unsigned long addr, pte_t *ptep, pte_t pte) { radix__set_pte_at(kvm->mm, addr, ptep, pte, 0); } static struct kmem_cache *kvm_pte_cache; static pte_t *kvmppc_pte_alloc(void) { return kmem_cache_alloc(kvm_pte_cache, GFP_KERNEL); } static void kvmppc_pte_free(pte_t *ptep) { kmem_cache_free(kvm_pte_cache, ptep); } static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa, unsigned int level, unsigned long mmu_seq) { pgd_t *pgd; pud_t *pud, *new_pud = NULL; pmd_t *pmd, *new_pmd = NULL; pte_t *ptep, *new_ptep = NULL; unsigned long old; int ret; /* Traverse the guest's 2nd-level tree, allocate new levels needed */ pgd = kvm->arch.pgtable + pgd_index(gpa); pud = NULL; if (pgd_present(*pgd)) pud = pud_offset(pgd, gpa); else new_pud = pud_alloc_one(kvm->mm, gpa); pmd = NULL; if (pud && pud_present(*pud)) pmd = pmd_offset(pud, gpa); else new_pmd = pmd_alloc_one(kvm->mm, gpa); if (level == 0 && !(pmd && pmd_present(*pmd))) new_ptep = kvmppc_pte_alloc(); /* Check if we might have been invalidated; let the guest retry if so */ spin_lock(&kvm->mmu_lock); ret = -EAGAIN; if (mmu_notifier_retry(kvm, mmu_seq)) goto out_unlock; /* Now traverse again under the lock and change the tree */ ret = -ENOMEM; if (pgd_none(*pgd)) { if (!new_pud) goto out_unlock; pgd_populate(kvm->mm, pgd, new_pud); new_pud = NULL; } pud = pud_offset(pgd, gpa); if (pud_none(*pud)) { if (!new_pmd) goto out_unlock; pud_populate(kvm->mm, pud, new_pmd); new_pmd = NULL; } pmd = pmd_offset(pud, gpa); if (pmd_large(*pmd)) { /* Someone else has instantiated a large page here; retry */ ret = -EAGAIN; goto out_unlock; } if (level == 1 && !pmd_none(*pmd)) { /* * There's a page table page here, but we wanted * to install a large page. Tell the caller and let * it try installing a normal page if it wants. */ ret = -EBUSY; goto out_unlock; } if (level == 0) { if (pmd_none(*pmd)) { if (!new_ptep) goto out_unlock; pmd_populate(kvm->mm, pmd, new_ptep); new_ptep = NULL; } ptep = pte_offset_kernel(pmd, gpa); if (pte_present(*ptep)) { /* PTE was previously valid, so invalidate it */ old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT, 0, gpa, 0); kvmppc_radix_tlbie_page(kvm, gpa, 0); if (old & _PAGE_DIRTY) mark_page_dirty(kvm, gpa >> PAGE_SHIFT); } kvmppc_radix_set_pte_at(kvm, gpa, ptep, pte); } else { kvmppc_radix_set_pte_at(kvm, gpa, pmdp_ptep(pmd), pte); } ret = 0; out_unlock: spin_unlock(&kvm->mmu_lock); if (new_pud) pud_free(kvm->mm, new_pud); if (new_pmd) pmd_free(kvm->mm, new_pmd); if (new_ptep) kvmppc_pte_free(new_ptep); return ret; } int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, unsigned long ea, unsigned long dsisr) { struct kvm *kvm = vcpu->kvm; unsigned long mmu_seq, pte_size; unsigned long gpa, gfn, hva, pfn; struct kvm_memory_slot *memslot; struct page *page = NULL, *pages[1]; long ret, npages, ok; unsigned int writing; struct vm_area_struct *vma; unsigned long flags; pte_t pte, *ptep; unsigned long pgflags; unsigned int shift, level; /* Check for unusual errors */ if (dsisr & DSISR_UNSUPP_MMU) { pr_err("KVM: Got unsupported MMU fault\n"); return -EFAULT; } if (dsisr & DSISR_BADACCESS) { /* Reflect to the guest as DSI */ pr_err("KVM: Got radix HV page fault with DSISR=%lx\n", dsisr); kvmppc_core_queue_data_storage(vcpu, ea, dsisr); return RESUME_GUEST; } /* Translate the logical address and get the page */ gpa = vcpu->arch.fault_gpa & ~0xfffUL; gpa &= ~0xF000000000000000ul; gfn = gpa >> PAGE_SHIFT; if (!(dsisr & DSISR_PRTABLE_FAULT)) gpa |= ea & 0xfff; memslot = gfn_to_memslot(kvm, gfn); /* No memslot means it's an emulated MMIO region */ if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID)) { if (dsisr & (DSISR_PRTABLE_FAULT | DSISR_BADACCESS | DSISR_SET_RC)) { /* * Bad address in guest page table tree, or other * unusual error - reflect it to the guest as DSI. */ kvmppc_core_queue_data_storage(vcpu, ea, dsisr); return RESUME_GUEST; } return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea, dsisr & DSISR_ISSTORE); } /* used to check for invalidations in progress */ mmu_seq = kvm->mmu_notifier_seq; smp_rmb(); writing = (dsisr & DSISR_ISSTORE) != 0; hva = gfn_to_hva_memslot(memslot, gfn); if (dsisr & DSISR_SET_RC) { /* * Need to set an R or C bit in the 2nd-level tables; * if the relevant bits aren't already set in the linux * page tables, fall through to do the gup_fast to * set them in the linux page tables too. */ ok = 0; pgflags = _PAGE_ACCESSED; if (writing) pgflags |= _PAGE_DIRTY; local_irq_save(flags); ptep = find_current_mm_pte(current->mm->pgd, hva, NULL, NULL); if (ptep) { pte = READ_ONCE(*ptep); if (pte_present(pte) && (pte_val(pte) & pgflags) == pgflags) ok = 1; } local_irq_restore(flags); if (ok) { spin_lock(&kvm->mmu_lock); if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) { spin_unlock(&kvm->mmu_lock); return RESUME_GUEST; } /* * We are walking the secondary page table here. We can do this * without disabling irq. */ ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); if (ptep && pte_present(*ptep)) { kvmppc_radix_update_pte(kvm, ptep, 0, pgflags, gpa, shift); spin_unlock(&kvm->mmu_lock); return RESUME_GUEST; } spin_unlock(&kvm->mmu_lock); } } ret = -EFAULT; pfn = 0; pte_size = PAGE_SIZE; pgflags = _PAGE_READ | _PAGE_EXEC; level = 0; npages = get_user_pages_fast(hva, 1, writing, pages); if (npages < 1) { /* Check if it's an I/O mapping */ down_read(¤t->mm->mmap_sem); vma = find_vma(current->mm, hva); if (vma && vma->vm_start <= hva && hva < vma->vm_end && (vma->vm_flags & VM_PFNMAP)) { pfn = vma->vm_pgoff + ((hva - vma->vm_start) >> PAGE_SHIFT); pgflags = pgprot_val(vma->vm_page_prot); } up_read(¤t->mm->mmap_sem); if (!pfn) return -EFAULT; } else { page = pages[0]; pfn = page_to_pfn(page); if (PageHuge(page)) { page = compound_head(page); pte_size <<= compound_order(page); /* See if we can insert a 2MB large-page PTE here */ if (pte_size >= PMD_SIZE && (gpa & PMD_MASK & PAGE_MASK) == (hva & PMD_MASK & PAGE_MASK)) { level = 1; pfn &= ~((PMD_SIZE >> PAGE_SHIFT) - 1); } } /* See if we can provide write access */ if (writing) { /* * We assume gup_fast has set dirty on the host PTE. */ pgflags |= _PAGE_WRITE; } else { local_irq_save(flags); ptep = find_current_mm_pte(current->mm->pgd, hva, NULL, NULL); if (ptep && pte_write(*ptep) && pte_dirty(*ptep)) pgflags |= _PAGE_WRITE; local_irq_restore(flags); } } /* * Compute the PTE value that we need to insert. */ pgflags |= _PAGE_PRESENT | _PAGE_PTE | _PAGE_ACCESSED; if (pgflags & _PAGE_WRITE) pgflags |= _PAGE_DIRTY; pte = pfn_pte(pfn, __pgprot(pgflags)); /* Allocate space in the tree and write the PTE */ ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq); if (ret == -EBUSY) { /* * There's already a PMD where wanted to install a large page; * for now, fall back to installing a small page. */ level = 0; pfn |= gfn & ((PMD_SIZE >> PAGE_SHIFT) - 1); pte = pfn_pte(pfn, __pgprot(pgflags)); ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq); } if (ret == 0 || ret == -EAGAIN) ret = RESUME_GUEST; if (page) { /* * We drop pages[0] here, not page because page might * have been set to the head page of a compound, but * we have to drop the reference on the correct tail * page to match the get inside gup() */ put_page(pages[0]); } return ret; } static void mark_pages_dirty(struct kvm *kvm, struct kvm_memory_slot *memslot, unsigned long gfn, unsigned int order) { unsigned long i, limit; unsigned long *dp; if (!memslot->dirty_bitmap) return; limit = 1ul << order; if (limit < BITS_PER_LONG) { for (i = 0; i < limit; ++i) mark_page_dirty(kvm, gfn + i); return; } dp = memslot->dirty_bitmap + (gfn - memslot->base_gfn); limit /= BITS_PER_LONG; for (i = 0; i < limit; ++i) *dp++ = ~0ul; } /* Called with kvm->lock held */ int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot, unsigned long gfn) { pte_t *ptep; unsigned long gpa = gfn << PAGE_SHIFT; unsigned int shift; unsigned long old; ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); if (ptep && pte_present(*ptep)) { old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT, 0, gpa, shift); kvmppc_radix_tlbie_page(kvm, gpa, shift); if (old & _PAGE_DIRTY) { if (!shift) mark_page_dirty(kvm, gfn); else mark_pages_dirty(kvm, memslot, gfn, shift - PAGE_SHIFT); } } return 0; } /* Called with kvm->lock held */ int kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot, unsigned long gfn) { pte_t *ptep; unsigned long gpa = gfn << PAGE_SHIFT; unsigned int shift; int ref = 0; ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); if (ptep && pte_present(*ptep) && pte_young(*ptep)) { kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0, gpa, shift); /* XXX need to flush tlb here? */ ref = 1; } return ref; } /* Called with kvm->lock held */ int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot, unsigned long gfn) { pte_t *ptep; unsigned long gpa = gfn << PAGE_SHIFT; unsigned int shift; int ref = 0; ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); if (ptep && pte_present(*ptep) && pte_young(*ptep)) ref = 1; return ref; } /* Returns the number of PAGE_SIZE pages that are dirty */ static int kvm_radix_test_clear_dirty(struct kvm *kvm, struct kvm_memory_slot *memslot, int pagenum) { unsigned long gfn = memslot->base_gfn + pagenum; unsigned long gpa = gfn << PAGE_SHIFT; pte_t *ptep; unsigned int shift; int ret = 0; ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) { ret = 1; if (shift) ret = 1 << (shift - PAGE_SHIFT); kvmppc_radix_update_pte(kvm, ptep, _PAGE_DIRTY, 0, gpa, shift); kvmppc_radix_tlbie_page(kvm, gpa, shift); } return ret; } long kvmppc_hv_get_dirty_log_radix(struct kvm *kvm, struct kvm_memory_slot *memslot, unsigned long *map) { unsigned long i, j; unsigned long n, *p; int npages; /* * Radix accumulates dirty bits in the first half of the * memslot's dirty_bitmap area, for when pages are paged * out or modified by the host directly. Pick up these * bits and add them to the map. */ n = kvm_dirty_bitmap_bytes(memslot) / sizeof(long); p = memslot->dirty_bitmap; for (i = 0; i < n; ++i) map[i] |= xchg(&p[i], 0); for (i = 0; i < memslot->npages; i = j) { npages = kvm_radix_test_clear_dirty(kvm, memslot, i); /* * Note that if npages > 0 then i must be a multiple of npages, * since huge pages are only used to back the guest at guest * real addresses that are a multiple of their size. * Since we have at most one PTE covering any given guest * real address, if npages > 1 we can skip to i + npages. */ j = i + 1; if (npages) for (j = i; npages; ++j, --npages) __set_bit_le(j, map); } return 0; } static void add_rmmu_ap_encoding(struct kvm_ppc_rmmu_info *info, int psize, int *indexp) { if (!mmu_psize_defs[psize].shift) return; info->ap_encodings[*indexp] = mmu_psize_defs[psize].shift | (mmu_psize_defs[psize].ap << 29); ++(*indexp); } int kvmhv_get_rmmu_info(struct kvm *kvm, struct kvm_ppc_rmmu_info *info) { int i; if (!radix_enabled()) return -EINVAL; memset(info, 0, sizeof(*info)); /* 4k page size */ info->geometries[0].page_shift = 12; info->geometries[0].level_bits[0] = 9; for (i = 1; i < 4; ++i) info->geometries[0].level_bits[i] = p9_supported_radix_bits[i]; /* 64k page size */ info->geometries[1].page_shift = 16; for (i = 0; i < 4; ++i) info->geometries[1].level_bits[i] = p9_supported_radix_bits[i]; i = 0; add_rmmu_ap_encoding(info, MMU_PAGE_4K, &i); add_rmmu_ap_encoding(info, MMU_PAGE_64K, &i); add_rmmu_ap_encoding(info, MMU_PAGE_2M, &i); add_rmmu_ap_encoding(info, MMU_PAGE_1G, &i); return 0; } int kvmppc_init_vm_radix(struct kvm *kvm) { kvm->arch.pgtable = pgd_alloc(kvm->mm); if (!kvm->arch.pgtable) return -ENOMEM; return 0; } void kvmppc_free_radix(struct kvm *kvm) { unsigned long ig, iu, im; pte_t *pte; pmd_t *pmd; pud_t *pud; pgd_t *pgd; if (!kvm->arch.pgtable) return; pgd = kvm->arch.pgtable; for (ig = 0; ig < PTRS_PER_PGD; ++ig, ++pgd) { if (!pgd_present(*pgd)) continue; pud = pud_offset(pgd, 0); for (iu = 0; iu < PTRS_PER_PUD; ++iu, ++pud) { if (!pud_present(*pud)) continue; pmd = pmd_offset(pud, 0); for (im = 0; im < PTRS_PER_PMD; ++im, ++pmd) { if (pmd_huge(*pmd)) { pmd_clear(pmd); continue; } if (!pmd_present(*pmd)) continue; pte = pte_offset_map(pmd, 0); memset(pte, 0, sizeof(long) << PTE_INDEX_SIZE); kvmppc_pte_free(pte); pmd_clear(pmd); } pmd_free(kvm->mm, pmd_offset(pud, 0)); pud_clear(pud); } pud_free(kvm->mm, pud_offset(pgd, 0)); pgd_clear(pgd); } pgd_free(kvm->mm, kvm->arch.pgtable); } static void pte_ctor(void *addr) { memset(addr, 0, PTE_TABLE_SIZE); } int kvmppc_radix_init(void) { unsigned long size = sizeof(void *) << PTE_INDEX_SIZE; kvm_pte_cache = kmem_cache_create("kvm-pte", size, size, 0, pte_ctor); if (!kvm_pte_cache) return -ENOMEM; return 0; } void kvmppc_radix_exit(void) { kmem_cache_destroy(kvm_pte_cache); }