From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754464Ab3JXJck (ORCPT ); Thu, 24 Oct 2013 05:32:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:21740 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753832Ab3JXJcj (ORCPT ); Thu, 24 Oct 2013 05:32:39 -0400 Date: Thu, 24 Oct 2013 12:32:33 +0300 From: Gleb Natapov To: Xiao Guangrong Cc: avi.kivity@gmail.com, mtosatti@redhat.com, pbonzini@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH v3 13/15] KVM: MMU: locklessly write-protect the page Message-ID: <20131024093233.GC5289@redhat.com> References: <1382534973-13197-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <1382534973-13197-14-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <20131024091732.GA5289@redhat.com> <5268E73C.7030302@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5268E73C.7030302@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 24, 2013 at 05:24:12PM +0800, Xiao Guangrong wrote: > On 10/24/2013 05:17 PM, Gleb Natapov wrote: > > >> > >> -/** > >> - * kvm_mmu_write_protect_pt_masked - write protect selected PT level pages > >> +static void __rmap_write_protect_lockless(u64 *sptep) > >> +{ > >> + u64 spte; > >> + > >> +retry: > >> + /* > >> + * Note we may partly read the sptep on 32bit host, however, we > >> + * allow this case because: > >> + * - we do not access the page got from the sptep. > >> + * - cmpxchg64 can detect that case and avoid setting a wrong value > >> + * to the sptep. > >> + */ > >> + spte = *rcu_dereference(sptep); > >> + if (unlikely(!is_last_spte(spte) || !is_writable_pte(spte))) > > is_last_spte gets two parameters. > > In patch [PATCH v3 12/15] KVM: MMU: check last spte with unawareness of mapping level, > we have removed the 'level' from the parameter list. Ah, I haven't got 12/15 and git am did not complain :( -- Gleb.