diff options
| -rw-r--r-- | drivers/kvm/kvm.h | 1 | ||||
| -rw-r--r-- | drivers/kvm/mmu.c | 21 | ||||
| -rw-r--r-- | drivers/kvm/paging_tmpl.h | 9 |
3 files changed, 29 insertions, 2 deletions
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h index 7de948e..08ffc82 100644 --- a/drivers/kvm/kvm.h +++ b/drivers/kvm/kvm.h @@ -346,6 +346,7 @@ struct kvm_vcpu { gfn_t last_pt_write_gfn; int last_pt_write_count; + u64 *last_pte_updated; struct kvm_guest_debug guest_debug; diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c index 069ce83..d347e89 100644 --- a/drivers/kvm/mmu.c +++ b/drivers/kvm/mmu.c @@ -692,6 +692,15 @@ static void kvm_mmu_put_page(struct kvm_mmu_page *page, mmu_page_remove_parent_pte(page, parent_pte); } +static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm) +{ + int i; + + for (i = 0; i < KVM_MAX_VCPUS; ++i) + if (kvm->vcpus[i]) + kvm->vcpus[i]->last_pte_updated = NULL; +} + static void kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *page) { @@ -717,6 +726,7 @@ static void kvm_mmu_zap_page(struct kvm *kvm, kvm_mmu_free_page(kvm, page); } else list_move(&page->link, &kvm->active_mmu_pages); + kvm_mmu_reset_last_pte_updated(kvm); } static int kvm_mmu_unprotect_page(struct kvm_vcpu *vcpu, gfn_t gfn) @@ -1140,6 +1150,13 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu, offset_in_pte); } +static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu) +{ + u64 *spte = vcpu->last_pte_updated; + + return !!(spte && (*spte & PT_ACCESSED_MASK)); +} + void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, int bytes) { @@ -1160,13 +1177,15 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes); kvm_mmu_audit(vcpu, "pre pte write"); - if (gfn == vcpu->last_pt_write_gfn) { + if (gfn == vcpu->last_pt_write_gfn + && !last_updated_pte_accessed(vcpu)) { ++vcpu->last_pt_write_count; if (vcpu->last_pt_write_count >= 3) flooded = 1; } else { vcpu->last_pt_write_gfn = gfn; vcpu->last_pt_write_count = 1; + vcpu->last_pte_updated = NULL; } index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES; bucket = &vcpu->kvm->mmu_page_hash[index]; diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h index 99ac9b1..be0f852 100644 --- a/drivers/kvm/paging_tmpl.h +++ b/drivers/kvm/paging_tmpl.h @@ -238,7 +238,12 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu, FNAME(mark_pagetable_dirty)(vcpu->kvm, walker); } - spte = PT_PRESENT_MASK | PT_ACCESSED_MASK | PT_DIRTY_MASK; + /* + * We don't set the accessed bit, since we sometimes want to see + * whether the guest actually used the pte (in order to detect + * demand paging). + */ + spte = PT_PRESENT_MASK | PT_DIRTY_MASK; spte |= gpte & PT64_NX_MASK; if (!dirty) access_bits &= ~PT_WRITABLE_MASK; @@ -291,6 +296,8 @@ unshadowed: page_header_update_slot(vcpu->kvm, shadow_pte, gaddr); if (!was_rmapped) rmap_add(vcpu, shadow_pte); + if (!ptwrite || !*ptwrite) + vcpu->last_pte_updated = shadow_pte; } static void FNAME(set_pte)(struct kvm_vcpu *vcpu, pt_element_t gpte, |