From patchwork Wed Jun 10 15:27:04 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Tosatti X-Patchwork-Id: 29311 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n5AFVXGY010914 for ; Wed, 10 Jun 2009 15:31:34 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759671AbZFJPb2 (ORCPT ); Wed, 10 Jun 2009 11:31:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759769AbZFJPb2 (ORCPT ); Wed, 10 Jun 2009 11:31:28 -0400 Received: from mx2.redhat.com ([66.187.237.31]:56492 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758374AbZFJPbY (ORCPT ); Wed, 10 Jun 2009 11:31:24 -0400 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n5AFVRM5018611 for ; Wed, 10 Jun 2009 11:31:27 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n5AFVPVq021543; Wed, 10 Jun 2009 11:31:25 -0400 Received: from amt.cnet (vpn-10-153.str.redhat.com [10.32.10.153]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n5AFVMVn019096; Wed, 10 Jun 2009 11:31:23 -0400 Received: from amt.cnet (amt.cnet [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id 6C130550004; Wed, 10 Jun 2009 12:30:40 -0300 (BRT) Received: (from marcelo@localhost) by amt.cnet (8.14.3/8.14.3/Submit) id n5AFUdcD011123; Wed, 10 Jun 2009 12:30:39 -0300 Message-Id: <20090610152747.558682414@localhost.localdomain> References: <20090610152702.666650177@localhost.localdomain> User-Agent: quilt/0.46-1 Date: Wed, 10 Jun 2009 12:27:04 -0300 From: Marcelo Tosatti To: avi@redhat.com Cc: kvm@vger.kernel.org, Marcelo Tosatti Subject: [patch 2/6] KVM: MMU audit: update count_writable_mappings / count_rmaps Content-Disposition: inline; filename=mmu-audit-1 X-Scanned-By: MIMEDefang 2.58 on 172.16.27.26 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Under testing, count_writable_mappings returns a value that is 2 integers larger than what count_rmaps returns. Suspicion is that either of the two functions is counting a duplicate (either positively or negatively). Modifying check_writable_mappings_rmap to check for rmap existance on all present MMU pages fails to trigger an error, which should keep Avi happy. Also introduce mmu_spte_walk to invoke a callback on all present sptes visible to the current vcpu, might be useful in the future. Signed-off-by: Marcelo Tosatti Index: kvm/arch/x86/kvm/mmu.c =================================================================== --- kvm.orig/arch/x86/kvm/mmu.c +++ kvm/arch/x86/kvm/mmu.c @@ -3020,6 +3020,55 @@ static gva_t canonicalize(gva_t gva) return gva; } + +typedef void (*inspect_spte_fn) (struct kvm *kvm, struct kvm_mmu_page *sp, + u64 *sptep); + +static void __mmu_spte_walk(struct kvm *kvm, struct kvm_mmu_page *sp, + inspect_spte_fn fn) +{ + int i; + + for (i = 0; i < PT64_ENT_PER_PAGE; ++i) { + u64 ent = sp->spt[i]; + + if (is_shadow_present_pte(ent)) { + if (sp->role.level > 1 && !is_large_pte(ent)) { + struct kvm_mmu_page *child; + child = page_header(ent & PT64_BASE_ADDR_MASK); + __mmu_spte_walk(kvm, child, fn); + } + if (sp->role.level == 1) + fn(kvm, sp, &sp->spt[i]); + } + } +} + +static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn) +{ + int i; + struct kvm_mmu_page *sp; + + if (!VALID_PAGE(vcpu->arch.mmu.root_hpa)) + return; + if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) { + hpa_t root = vcpu->arch.mmu.root_hpa; + sp = page_header(root); + __mmu_spte_walk(vcpu->kvm, sp, fn); + return; + } + for (i = 0; i < 4; ++i) { + hpa_t root = vcpu->arch.mmu.pae_root[i]; + + if (root && VALID_PAGE(root)) { + root &= PT64_BASE_ADDR_MASK; + sp = page_header(root); + __mmu_spte_walk(vcpu->kvm, sp, fn); + } + } + return; +} + static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte, gva_t va, int level) { @@ -3112,9 +3161,47 @@ static int count_rmaps(struct kvm_vcpu * return nmaps; } -static int count_writable_mappings(struct kvm_vcpu *vcpu) +void inspect_spte_has_rmap(struct kvm *kvm, struct kvm_mmu_page *sp, u64 *sptep) +{ + unsigned long *rmapp; + struct kvm_mmu_page *rev_sp; + gfn_t gfn; + + if (*sptep & PT_WRITABLE_MASK) { + rev_sp = page_header(__pa(sptep)); + gfn = rev_sp->gfns[sptep - rev_sp->spt]; + + if (!gfn_to_memslot(kvm, gfn)) { + if (!printk_ratelimit()) + return; + printk(KERN_ERR "%s: no memslot for gfn %ld\n", + audit_msg, gfn); + printk(KERN_ERR "%s: index %ld of sp (gfn=%lx)\n", + audit_msg, sptep - rev_sp->spt, + rev_sp->gfn); + dump_stack(); + return; + } + + rmapp = gfn_to_rmap(kvm, rev_sp->gfns[sptep - rev_sp->spt], 0); + if (!*rmapp) { + if (!printk_ratelimit()) + return; + printk(KERN_ERR "%s: no rmap for writable spte %llx\n", + audit_msg, *sptep); + dump_stack(); + } + } + +} + +void audit_writable_sptes_have_rmaps(struct kvm_vcpu *vcpu) +{ + mmu_spte_walk(vcpu, inspect_spte_has_rmap); +} + +static void check_writable_mappings_rmap(struct kvm_vcpu *vcpu) { - int nmaps = 0; struct kvm_mmu_page *sp; int i; @@ -3131,20 +3218,16 @@ static int count_writable_mappings(struc continue; if (!(ent & PT_WRITABLE_MASK)) continue; - ++nmaps; + inspect_spte_has_rmap(vcpu->kvm, sp, &pt[i]); } } - return nmaps; + return; } static void audit_rmap(struct kvm_vcpu *vcpu) { - int n_rmap = count_rmaps(vcpu); - int n_actual = count_writable_mappings(vcpu); - - if (n_rmap != n_actual) - printk(KERN_ERR "%s: (%s) rmap %d actual %d\n", - __func__, audit_msg, n_rmap, n_actual); + check_writable_mappings_rmap(vcpu); + count_rmaps(vcpu); } static void audit_write_protection(struct kvm_vcpu *vcpu) @@ -3178,6 +3261,7 @@ static void kvm_mmu_audit(struct kvm_vcp audit_rmap(vcpu); audit_write_protection(vcpu); audit_mappings(vcpu); + audit_writable_sptes_have_rmaps(vcpu); dbg = olddbg; }