From mboxrd@z Thu Jan 1 00:00:00 1970 From: Izik Eidus Subject: [PATCH 1/3] kvm: dont hold pagecount reference for mapped sptes pages Date: Wed, 23 Sep 2009 21:47:16 +0300 Message-ID: <1253731638-24575-2-git-send-email-ieidus@redhat.com> References: <1253731638-24575-1-git-send-email-ieidus@redhat.com> Cc: kvm@vger.kernel.org, aarcange@redhat.com, mtosatti@redhat.com, Izik Eidus To: avi@redhat.com Return-path: Received: from mx1.redhat.com ([209.132.183.28]:39140 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752353AbZIWSif (ORCPT ); Wed, 23 Sep 2009 14:38:35 -0400 Received: from int-mx08.intmail.prod.int.phx2.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id n8NIccUf004431 for ; Wed, 23 Sep 2009 14:38:39 -0400 In-Reply-To: <1253731638-24575-1-git-send-email-ieidus@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: When using mmu notifiers, we are allowed to remove the page count reference tooken by get_user_pages to a specific page that is mapped inside the shadow page tables. This is needed so we can balance the pagecount against mapcount checking. (Right now kvm increase the pagecount and does not increase the mapcount when mapping page into shadow page table entry, so when comparing pagecount against mapcount, you have no reliable result.) Signed-off-by: Izik Eidus --- arch/x86/kvm/mmu.c | 7 ++----- 1 files changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index eca41ae..6c67b23 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -634,9 +634,7 @@ static void rmap_remove(struct kvm *kvm, u64 *spte) if (*spte & shadow_accessed_mask) kvm_set_pfn_accessed(pfn); if (is_writeble_pte(*spte)) - kvm_release_pfn_dirty(pfn); - else - kvm_release_pfn_clean(pfn); + kvm_set_pfn_dirty(pfn); rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], sp->role.level); if (!*rmapp) { printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte); @@ -1877,8 +1875,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, page_header_update_slot(vcpu->kvm, sptep, gfn); if (!was_rmapped) { rmap_count = rmap_add(vcpu, sptep, gfn); - if (!is_rmap_spte(*sptep)) - kvm_release_pfn_clean(pfn); + kvm_release_pfn_clean(pfn); if (rmap_count > RMAP_RECYCLE_THRESHOLD) rmap_recycle(vcpu, sptep, gfn); } else { -- 1.5.6.5