From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 02/11] KVM: x86: tag the instructions which are used to write page table Date: Mon, 22 Aug 2011 17:36:37 +0300 Message-ID: <4E526975.4080106@redhat.com> References: <4E4A10E8.5090705@cn.fujitsu.com> <4E4A1117.1030608@cn.fujitsu.com> <20110822143235.GA4797@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Xiao Guangrong , LKML , KVM To: Marcelo Tosatti Return-path: 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 In-Reply-To: <20110822143235.GA4797@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: 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