From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754418Ab1G0Jfz (ORCPT ); Wed, 27 Jul 2011 05:35:55 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:65352 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754036Ab1G0Jfx (ORCPT ); Wed, 27 Jul 2011 05:35:53 -0400 Message-ID: <4E2FDC6F.4050006@cn.fujitsu.com> Date: Wed, 27 Jul 2011 17:37:51 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10 MIME-Version: 1.0 To: Avi Kivity 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> <4E2FD499.2070308@redhat.com> In-Reply-To: <4E2FD499.2070308@redhat.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-07-27 17:34:56, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-07-27 17:34:58, Serialize complete at 2011-07-27 17:34:58 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/27/2011 05:04 PM, Avi Kivity wrote: > 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. > OK, will do it in the next version, thanks!