From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754253Ab1G0JEe (ORCPT ); Wed, 27 Jul 2011 05:04:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45099 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754225Ab1G0JEb (ORCPT ); Wed, 27 Jul 2011 05:04:31 -0400 Message-ID: <4E2FD499.2070308@redhat.com> Date: Wed, 27 Jul 2011 12:04:25 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.18) Gecko/20110621 Fedora/3.1.11-1.fc15 Thunderbird/3.1.11 MIME-Version: 1.0 To: Xiao Guangrong CC: Marcelo Tosatti , LKML , KVM Subject: Re: [PATCH 03/11] KVM: x86: fast emulate repeat string write instructions References: <4E2EA3DB.7040403@cn.fujitsu.com> <4E2EA476.9070607@cn.fujitsu.com> In-Reply-To: <4E2EA476.9070607@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/26/2011 02:26 PM, Xiao Guangrong wrote: > We usually use repeat string instructions to clear the page, for example, > we call memset to clear a page table, stosb is used in this function, and > repeated for 1024 times, that means we should occupy mmu lock for 1024 times > and walking shadow page cache for 1024 times, it is terrible > > In fact, if it is the repeat string instructions emulated and it is not a > IO/MMIO access, we can zap all the corresponding shadow pages and return to the > guest, then the mapping can became writable and directly write the page Please generalize this to fail emulation on all non-page-table instructions when emulating due to a write protected page that we can unprotect. -- error compiling committee.c: too many arguments to function