From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755310Ab0GCMfz (ORCPT ); Sat, 3 Jul 2010 08:35:55 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:59170 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755083Ab0GCMfx (ORCPT ); Sat, 3 Jul 2010 08:35:53 -0400 Message-ID: <4C2F2DBB.50904@cn.fujitsu.com> Date: Sat, 03 Jul 2010 20:31:55 +0800 From: Xiao Guangrong User-Agent: Thunderbird 2.0.0.24 (Windows/20100228) MIME-Version: 1.0 To: Avi Kivity CC: Marcelo Tosatti , LKML , KVM list Subject: Re: [PATCH v4 5/6] KVM: MMU: combine guest pte read between walk and pte prefetch References: <4C2C9DC0.8050607@cn.fujitsu.com> <4C2C9E6C.2040803@cn.fujitsu.com> <20100702170303.GC25969@amt.cnet> <4C2F117C.2000006@cn.fujitsu.com> <4C2F2835.5060508@redhat.com> <4C2F2A0C.90704@cn.fujitsu.com> <4C2F2C5B.9020503@redhat.com> In-Reply-To: <4C2F2C5B.9020503@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Avi Kivity wrote: >> > > if (!direct) { > r = kvm_read_guest_atomic(vcpu->kvm, > gw->pte_gpa[level - 2], > &curr_pte, sizeof(curr_pte)); > if (r || curr_pte != gw->ptes[level - 2]) { > kvm_mmu_put_page(shadow_page, sptep); > kvm_release_pfn_clean(pfn); > sptep = NULL; > break; > } > } > > the code you moved... under what scenario is it not sufficient? > I not move those code, just use common function instead, that it's FNAME(check_level_mapping)(), there are do the same work. And this check is not sufficient, since it's only checked if the mapping is zapped or not exist, for other words only when broken this judgment: is_shadow_present_pte(*sptep) && !is_large_pte(*sptep) but if the middle level is present and it's not the large mapping, this check is skipped.