From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752990Ab1HVOgn (ORCPT ); Mon, 22 Aug 2011 10:36:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61229 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750818Ab1HVOgl (ORCPT ); Mon, 22 Aug 2011 10:36:41 -0400 Message-ID: <4E526975.4080106@redhat.com> Date: Mon, 22 Aug 2011 17:36:37 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:5.0) Gecko/20110707 Thunderbird/5.0 MIME-Version: 1.0 To: Marcelo Tosatti CC: Xiao Guangrong , LKML , KVM Subject: Re: [PATCH 02/11] KVM: x86: tag the instructions which are used to write page table References: <4E4A10E8.5090705@cn.fujitsu.com> <4E4A1117.1030608@cn.fujitsu.com> <20110822143235.GA4797@amt.cnet> In-Reply-To: <20110822143235.GA4797@amt.cnet> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/22/2011 05:32 PM, Marcelo Tosatti wrote: > On Tue, Aug 16, 2011 at 02:41:27PM +0800, Xiao Guangrong wrote: > > The idea is from Avi: > > | tag instructions that are typically used to modify the page tables, and > > | drop shadow if any other instruction is used. > > | The list would include, I'd guess, and, or, bts, btc, mov, xchg, cmpxchg, > > | and cmpxchg8b. > > > > This patch is used to tag the instructions and in the later path, shadow page > > is dropped if it is written by other instructions > > What is the advantage of doing this again? What is the point of > dropping shadow if the instruction is emulated? > So it won't be emulated again; the assumption is that if you addl into a page, it isn't a pagetable. -- error compiling committee.c: too many arguments to function