From patchwork Tue Jan 8 10:43:28 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takuya Yoshikawa X-Patchwork-Id: 1945041 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 46AFFDF23A for ; Tue, 8 Jan 2013 10:43:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755848Ab3AHKmy (ORCPT ); Tue, 8 Jan 2013 05:42:54 -0500 Received: from tama50.ecl.ntt.co.jp ([129.60.39.147]:57321 "EHLO tama50.ecl.ntt.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755828Ab3AHKmx (ORCPT ); Tue, 8 Jan 2013 05:42:53 -0500 Received: from mfs5.rdh.ecl.ntt.co.jp (mfs5.rdh.ecl.ntt.co.jp [129.60.39.144]) by tama50.ecl.ntt.co.jp (8.13.8/8.13.8) with ESMTP id r08AgoNi008267; Tue, 8 Jan 2013 19:42:50 +0900 Received: from mfs5.rdh.ecl.ntt.co.jp (localhost.localdomain [127.0.0.1]) by mfs5.rdh.ecl.ntt.co.jp (Postfix) with ESMTP id 84BF4E01AD; Tue, 8 Jan 2013 19:42:50 +0900 (JST) Received: from imail2.m.ecl.ntt.co.jp (imail2.m.ecl.ntt.co.jp [129.60.5.247]) by mfs5.rdh.ecl.ntt.co.jp (Postfix) with ESMTP id 78A7AE01AA; Tue, 8 Jan 2013 19:42:50 +0900 (JST) Received: from yshpad ([129.60.241.200]) by imail2.m.ecl.ntt.co.jp (8.13.8/8.13.8) with SMTP id r08AgooX020274; Tue, 8 Jan 2013 19:42:50 +0900 Date: Tue, 8 Jan 2013 19:43:28 +0900 From: Takuya Yoshikawa To: mtosatti@redhat.com, gleb@redhat.com Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/7] KVM: Write protect the updated slot only when dirty logging is enabled Message-Id: <20130108194328.af8c13ce.yoshikawa_takuya_b1@lab.ntt.co.jp> In-Reply-To: <20130108194238.09ebc8bd.yoshikawa_takuya_b1@lab.ntt.co.jp> References: <20130108194238.09ebc8bd.yoshikawa_takuya_b1@lab.ntt.co.jp> X-Mailer: Sylpheed 3.1.0 (GTK+ 2.24.4; x86_64-pc-linux-gnu) Mime-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Calling kvm_mmu_slot_remove_write_access() for a deleted slot does nothing but search for non-existent mmu pages which have mappings to that deleted memory; this is safe but a waste of time. Since we want to make the function rmap based in a later patch, in a manner which makes it unsafe to be called for a deleted slot, we makes the caller see if the slot is non-zero and being dirty logged. Signed-off-by: Takuya Yoshikawa --- arch/x86/kvm/x86.c | 8 +++++++- virt/kvm/kvm_main.c | 1 - 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1c9c834..add5e48 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6897,7 +6897,13 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, spin_lock(&kvm->mmu_lock); if (nr_mmu_pages) kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages); - kvm_mmu_slot_remove_write_access(kvm, mem->slot); + /* + * Write protect all pages for dirty logging. + * Existing largepage mappings are destroyed here and new ones will + * not be created until the end of the logging. + */ + if (npages && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES)) + kvm_mmu_slot_remove_write_access(kvm, mem->slot); spin_unlock(&kvm->mmu_lock); /* * If memory slot is created, or moved, we need to clear all diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index e45c20c..f689a6d 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -817,7 +817,6 @@ int __kvm_set_memory_region(struct kvm *kvm, if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) { if (kvm_create_dirty_bitmap(&new) < 0) goto out_free; - /* destroy any largepage mappings for dirty tracking */ } if (!npages || base_gfn != old.base_gfn) {