diff options
Diffstat (limited to 'arch/powerpc/kvm/book3s_64_mmu_radix.c')
-rw-r--r-- | arch/powerpc/kvm/book3s_64_mmu_radix.c | 150 |
1 files changed, 100 insertions, 50 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c index aa12cd4078b3..6a73714759ba 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c @@ -11,12 +11,12 @@ #include <linux/anon_inodes.h> #include <linux/file.h> #include <linux/debugfs.h> +#include <linux/pgtable.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> #include <asm/ultravisor.h> @@ -40,7 +40,8 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid, /* Can't access quadrants 1 or 2 in non-HV mode, call the HV to do it */ if (kvmhv_on_pseries()) return plpar_hcall_norets(H_COPY_TOFROM_GUEST, lpid, pid, eaddr, - __pa(to), __pa(from), n); + (to != NULL) ? __pa(to): 0, + (from != NULL) ? __pa(from): 0, n); quadrant = 1; if (!pid) @@ -64,9 +65,9 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid, isync(); if (is_load) - ret = probe_user_read(to, (const void __user *)from, n); + ret = copy_from_user_nofault(to, (const void __user *)from, n); else - ret = probe_user_write((void __user *)to, from, n); + ret = copy_to_user_nofault((void __user *)to, from, n); /* switch the pid first to avoid running host with unallocated pid */ if (quadrant == 1 && pid != old_pid) @@ -353,7 +354,13 @@ static struct kmem_cache *kvm_pmd_cache; static pte_t *kvmppc_pte_alloc(void) { - return kmem_cache_alloc(kvm_pte_cache, GFP_KERNEL); + pte_t *pte; + + pte = kmem_cache_alloc(kvm_pte_cache, GFP_KERNEL); + /* pmd_populate() will only reference _pa(pte). */ + kmemleak_ignore(pte); + + return pte; } static void kvmppc_pte_free(pte_t *ptep) @@ -363,7 +370,13 @@ static void kvmppc_pte_free(pte_t *ptep) static pmd_t *kvmppc_pmd_alloc(void) { - return kmem_cache_alloc(kvm_pmd_cache, GFP_KERNEL); + pmd_t *pmd; + + pmd = kmem_cache_alloc(kvm_pmd_cache, GFP_KERNEL); + /* pud_populate() will only reference _pa(pmd). */ + kmemleak_ignore(pmd); + + return pmd; } static void kvmppc_pmd_free(pmd_t *pmdp) @@ -417,9 +430,13 @@ void kvmppc_unmap_pte(struct kvm *kvm, pte_t *pte, unsigned long gpa, * Callers are responsible for flushing the PWC. * * When page tables are being unmapped/freed as part of page fault path - * (full == false), ptes are not expected. There is code to unmap them - * and emit a warning if encountered, but there may already be data - * corruption due to the unexpected mappings. + * (full == false), valid ptes are generally not expected; however, there + * is one situation where they arise, which is when dirty page logging is + * turned off for a memslot while the VM is running. The new memslot + * becomes visible to page faults before the memslot commit function + * gets to flush the memslot, which can lead to a 2MB page mapping being + * installed for a guest physical address where there are already 64kB + * (or 4kB) mappings (of sub-pages of the same 2MB page). */ static void kvmppc_unmap_free_pte(struct kvm *kvm, pte_t *pte, bool full, unsigned int lpid) @@ -433,7 +450,6 @@ static void kvmppc_unmap_free_pte(struct kvm *kvm, pte_t *pte, bool full, for (it = 0; it < PTRS_PER_PTE; ++it, ++p) { if (pte_val(*p) == 0) continue; - WARN_ON_ONCE(1); kvmppc_unmap_pte(kvm, p, pte_pfn(*p) << PAGE_SHIFT, PAGE_SHIFT, NULL, lpid); @@ -499,13 +515,14 @@ void kvmppc_free_pgtable_radix(struct kvm *kvm, pgd_t *pgd, unsigned int lpid) unsigned long ig; for (ig = 0; ig < PTRS_PER_PGD; ++ig, ++pgd) { + p4d_t *p4d = p4d_offset(pgd, 0); pud_t *pud; - if (!pgd_present(*pgd)) + if (!p4d_present(*p4d)) continue; - pud = pud_offset(pgd, 0); + pud = pud_offset(p4d, 0); kvmppc_unmap_free_pud(kvm, pud, lpid); - pgd_clear(pgd); + p4d_clear(p4d); } } @@ -566,6 +583,7 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, pte_t pte, unsigned long *rmapp, struct rmap_nested **n_rmap) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud, *new_pud = NULL; pmd_t *pmd, *new_pmd = NULL; pte_t *ptep, *new_ptep = NULL; @@ -573,9 +591,11 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, pte_t pte, /* Traverse the guest's 2nd-level tree, allocate new levels needed */ pgd = pgtable + pgd_index(gpa); + p4d = p4d_offset(pgd, gpa); + pud = NULL; - if (pgd_present(*pgd)) - pud = pud_offset(pgd, gpa); + if (p4d_present(*p4d)) + pud = pud_offset(p4d, gpa); else new_pud = pud_alloc_one(kvm->mm, gpa); @@ -596,13 +616,13 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, pte_t pte, /* Now traverse again under the lock and change the tree */ ret = -ENOMEM; - if (pgd_none(*pgd)) { + if (p4d_none(*p4d)) { if (!new_pud) goto out_unlock; - pgd_populate(kvm->mm, pgd, new_pud); + p4d_populate(kvm->mm, p4d, new_pud); new_pud = NULL; } - pud = pud_offset(pgd, gpa); + pud = pud_offset(p4d, gpa); if (pud_is_leaf(*pud)) { unsigned long hgpa = gpa & PUD_MASK; @@ -735,7 +755,7 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, pte_t pte, return ret; } -bool kvmppc_hv_handle_set_rc(struct kvm *kvm, pgd_t *pgtable, bool writing, +bool kvmppc_hv_handle_set_rc(struct kvm *kvm, bool nested, bool writing, unsigned long gpa, unsigned int lpid) { unsigned long pgflags; @@ -750,12 +770,12 @@ bool kvmppc_hv_handle_set_rc(struct kvm *kvm, pgd_t *pgtable, bool writing, pgflags = _PAGE_ACCESSED; if (writing) pgflags |= _PAGE_DIRTY; - /* - * We are walking the secondary (partition-scoped) page table here. - * We can do this without disabling irq because the Linux MM - * subsystem doesn't do THP splits and collapses on this tree. - */ - ptep = __find_linux_pte(pgtable, gpa, NULL, &shift); + + if (nested) + ptep = find_kvm_nested_guest_pte(kvm, lpid, gpa, &shift); + else + ptep = find_kvm_secondary_pte(kvm, gpa, &shift); + if (ptep && pte_present(*ptep) && (!writing || pte_write(*ptep))) { kvmppc_radix_update_pte(kvm, ptep, 0, pgflags, gpa, shift); return true; @@ -791,7 +811,7 @@ int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu, * is that the page is writable. */ hva = gfn_to_hva_memslot(memslot, gfn); - if (!kvm_ro && __get_user_pages_fast(hva, 1, 1, &page) == 1) { + if (!kvm_ro && get_user_page_fast_only(hva, FOLL_WRITE, &page)) { upgrade_write = true; } else { unsigned long pfn; @@ -813,12 +833,12 @@ int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu, * Read the PTE from the process' radix tree and use that * so we get the shift and attribute bits. */ - local_irq_disable(); - ptep = __find_linux_pte(vcpu->arch.pgdir, hva, NULL, &shift); + spin_lock(&kvm->mmu_lock); + ptep = find_kvm_host_pte(kvm, mmu_seq, hva, &shift); pte = __pte(0); if (ptep) - pte = *ptep; - local_irq_enable(); + pte = READ_ONCE(*ptep); + spin_unlock(&kvm->mmu_lock); /* * If the PTE disappeared temporarily due to a THP * collapse, just return and let the guest try again. @@ -887,7 +907,7 @@ int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu, return ret; } -int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, +int kvmppc_book3s_radix_page_fault(struct kvm_vcpu *vcpu, unsigned long ea, unsigned long dsisr) { struct kvm *kvm = vcpu->kvm; @@ -933,7 +953,7 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, kvmppc_core_queue_data_storage(vcpu, ea, dsisr); return RESUME_GUEST; } - return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea, writing); + return kvmppc_hv_emulate_mmio(vcpu, gpa, ea, writing); } if (memslot->flags & KVM_MEM_READONLY) { @@ -949,8 +969,8 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, /* Failed to set the reference/change bits */ if (dsisr & DSISR_SET_RC) { spin_lock(&kvm->mmu_lock); - if (kvmppc_hv_handle_set_rc(kvm, kvm->arch.pgtable, - writing, gpa, kvm->arch.lpid)) + if (kvmppc_hv_handle_set_rc(kvm, false, writing, + gpa, kvm->arch.lpid)) dsisr &= ~DSISR_SET_RC; spin_unlock(&kvm->mmu_lock); @@ -981,11 +1001,11 @@ int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot, return 0; } - ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); + ptep = find_kvm_secondary_pte(kvm, gpa, &shift); if (ptep && pte_present(*ptep)) kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot, kvm->arch.lpid); - return 0; + return 0; } /* Called with kvm->mmu_lock held */ @@ -1001,7 +1021,7 @@ int kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot, if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE) return ref; - ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); + ptep = find_kvm_secondary_pte(kvm, gpa, &shift); if (ptep && pte_present(*ptep) && pte_young(*ptep)) { old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0, gpa, shift); @@ -1028,7 +1048,7 @@ int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot, if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE) return ref; - ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); + ptep = find_kvm_secondary_pte(kvm, gpa, &shift); if (ptep && pte_present(*ptep) && pte_young(*ptep)) ref = 1; return ref; @@ -1040,7 +1060,7 @@ static int kvm_radix_test_clear_dirty(struct kvm *kvm, { unsigned long gfn = memslot->base_gfn + pagenum; unsigned long gpa = gfn << PAGE_SHIFT; - pte_t *ptep; + pte_t *ptep, pte; unsigned int shift; int ret = 0; unsigned long old, *rmapp; @@ -1048,12 +1068,35 @@ static int kvm_radix_test_clear_dirty(struct kvm *kvm, if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE) return ret; - 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); + /* + * For performance reasons we don't hold kvm->mmu_lock while walking the + * partition scoped table. + */ + ptep = find_kvm_secondary_pte_unlocked(kvm, gpa, &shift); + if (!ptep) + return 0; + + pte = READ_ONCE(*ptep); + if (pte_present(pte) && pte_dirty(pte)) { spin_lock(&kvm->mmu_lock); + /* + * Recheck the pte again + */ + if (pte_val(pte) != pte_val(*ptep)) { + /* + * We have KVM_MEM_LOG_DIRTY_PAGES enabled. Hence we can + * only find PAGE_SIZE pte entries here. We can continue + * to use the pte addr returned by above page table + * walk. + */ + if (!pte_present(*ptep) || !pte_dirty(*ptep)) { + spin_unlock(&kvm->mmu_lock); + return 0; + } + } + + ret = 1; + VM_BUG_ON(shift); old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_DIRTY, 0, gpa, shift); kvmppc_radix_tlbie_page(kvm, gpa, shift, kvm->arch.lpid); @@ -1109,12 +1152,17 @@ void kvmppc_radix_flush_memslot(struct kvm *kvm, gpa = memslot->base_gfn << PAGE_SHIFT; spin_lock(&kvm->mmu_lock); for (n = memslot->npages; n; --n) { - ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); + ptep = find_kvm_secondary_pte(kvm, gpa, &shift); if (ptep && pte_present(*ptep)) kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot, kvm->arch.lpid); gpa += PAGE_SIZE; } + /* + * Increase the mmu notifier sequence number to prevent any page + * fault that read the memslot earlier from writing a PTE. + */ + kvm->mmu_notifier_seq++; spin_unlock(&kvm->mmu_lock); } @@ -1220,7 +1268,8 @@ static ssize_t debugfs_radix_read(struct file *file, char __user *buf, unsigned long gpa; pgd_t *pgt; struct kvm_nested_guest *nested; - pgd_t pgd, *pgdp; + pgd_t *pgdp; + p4d_t p4d, *p4dp; pud_t pud, *pudp; pmd_t pmd, *pmdp; pte_t *ptep; @@ -1293,13 +1342,14 @@ static ssize_t debugfs_radix_read(struct file *file, char __user *buf, } pgdp = pgt + pgd_index(gpa); - pgd = READ_ONCE(*pgdp); - if (!(pgd_val(pgd) & _PAGE_PRESENT)) { - gpa = (gpa & PGDIR_MASK) + PGDIR_SIZE; + p4dp = p4d_offset(pgdp, gpa); + p4d = READ_ONCE(*p4dp); + if (!(p4d_val(p4d) & _PAGE_PRESENT)) { + gpa = (gpa & P4D_MASK) + P4D_SIZE; continue; } - pudp = pud_offset(&pgd, gpa); + pudp = pud_offset(&p4d, gpa); pud = READ_ONCE(*pudp); if (!(pud_val(pud) & _PAGE_PRESENT)) { gpa = (gpa & PUD_MASK) + PUD_SIZE; |