From patchwork Thu Sep 10 16:38:57 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Izik Eidus X-Patchwork-Id: 46625 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 n8AGV3GZ010533 for ; Thu, 10 Sep 2009 16:31:03 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752786AbZIJQa6 (ORCPT ); Thu, 10 Sep 2009 12:30:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752782AbZIJQa6 (ORCPT ); Thu, 10 Sep 2009 12:30:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13102 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752749AbZIJQa5 (ORCPT ); Thu, 10 Sep 2009 12:30:57 -0400 Received: from int-mx05.intmail.prod.int.phx2.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.18]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id n8AGV10T025188 for ; Thu, 10 Sep 2009 12:31:01 -0400 Received: from localhost.localdomain (dhcp-1-211.tlv.redhat.com [10.35.1.211]) by int-mx05.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id n8AGUrfg013014; Thu, 10 Sep 2009 12:30:59 -0400 From: Izik Eidus To: avi@redhat.com Cc: kvm@vger.kernel.org, aarcange@redhat.com, Izik Eidus Subject: [PATCH 2/3] add SPTE_HOST_WRITEABLE flag to the shadow ptes Date: Thu, 10 Sep 2009 19:38:57 +0300 Message-Id: <1252600738-9456-3-git-send-email-ieidus@redhat.com> In-Reply-To: <1252600738-9456-2-git-send-email-ieidus@redhat.com> References: <1252600738-9456-1-git-send-email-ieidus@redhat.com> <1252600738-9456-2-git-send-email-ieidus@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.18 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org this flag notify that the host physical page we are pointing to from the spte is write protected, and therefore we cant change its access to be write unless we run get_user_pages(write = 1). (this is needed for change_pte support in kvm) Signed-off-by: Izik Eidus --- arch/x86/kvm/mmu.c | 15 +++++++++++---- arch/x86/kvm/paging_tmpl.h | 18 +++++++++++++++--- 2 files changed, 26 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 62d2f86..a7151b8 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -156,6 +156,8 @@ module_param(oos_shadow, bool, 0644); #define CREATE_TRACE_POINTS #include "mmutrace.h" +#define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) + #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level) struct kvm_rmap_desc { @@ -1754,7 +1756,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, int user_fault, int write_fault, int dirty, int level, gfn_t gfn, pfn_t pfn, bool speculative, - bool can_unsync) + bool can_unsync, bool reset_host_protection) { u64 spte; int ret = 0; @@ -1781,6 +1783,9 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn, kvm_is_mmio_pfn(pfn)); + if (reset_host_protection) + spte |= SPTE_HOST_WRITEABLE; + spte |= (u64)pfn << PAGE_SHIFT; if ((pte_access & ACC_WRITE_MASK) @@ -1826,7 +1831,8 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pt_access, unsigned pte_access, int user_fault, int write_fault, int dirty, int *ptwrite, int level, gfn_t gfn, - pfn_t pfn, bool speculative) + pfn_t pfn, bool speculative, + bool reset_host_protection) { int was_rmapped = 0; int was_writeble = is_writeble_pte(*sptep); @@ -1858,7 +1864,8 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, } if (set_spte(vcpu, sptep, pte_access, user_fault, write_fault, - dirty, level, gfn, pfn, speculative, true)) { + dirty, level, gfn, pfn, speculative, true, + reset_host_protection)) { if (write_fault) *ptwrite = 1; kvm_x86_ops->tlb_flush(vcpu); @@ -1906,7 +1913,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write, if (iterator.level == level) { mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, ACC_ALL, 0, write, 1, &pt_write, - level, gfn, pfn, false); + level, gfn, pfn, false, true); ++vcpu->stat.pf_fixed; break; } diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index d2fec9c..c9256ee 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -273,9 +273,13 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page, if (mmu_notifier_retry(vcpu, vcpu->arch.update_pte.mmu_seq)) return; kvm_get_pfn(pfn); + /* + * we call mmu_set_spte() with reset_host_protection = true beacuse that + * vcpu->arch.update_pte.pfn was fetched from get_user_pages(write = 1). + */ mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0, gpte & PT_DIRTY_MASK, NULL, PT_PAGE_TABLE_LEVEL, - gpte_to_gfn(gpte), pfn, true); + gpte_to_gfn(gpte), pfn, true, true); } /* @@ -308,7 +312,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, user_fault, write_fault, gw->ptes[gw->level-1] & PT_DIRTY_MASK, ptwrite, level, - gw->gfn, pfn, false); + gw->gfn, pfn, false, true); break; } @@ -558,6 +562,7 @@ static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu, static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) { int i, offset, nr_present; + bool reset_host_protection; offset = nr_present = 0; @@ -595,9 +600,16 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) nr_present++; pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte); + if (!(sp->spt[i] & SPTE_HOST_WRITEABLE)) { + pte_access &= ~PT_WRITABLE_MASK; + reset_host_protection = 0; + } else { + reset_host_protection = 1; + } set_spte(vcpu, &sp->spt[i], pte_access, 0, 0, is_dirty_gpte(gpte), PT_PAGE_TABLE_LEVEL, gfn, - spte_to_pfn(sp->spt[i]), true, false); + spte_to_pfn(sp->spt[i]), true, false, + reset_host_protection); } return !nr_present;