Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755172Ab0KOJvM (ORCPT ); Mon, 15 Nov 2010 04:51:12 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:65004 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755043Ab0KOJvK (ORCPT ); Mon, 15 Nov 2010 04:51:10 -0500 Message-ID: <4CE1038D.9020403@cn.fujitsu.com> Date: Mon, 15 Nov 2010 17:55:25 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.11) Gecko/20100713 Thunderbird/3.0.6 MIME-Version: 1.0 To: Avi Kivity CC: Marcelo Tosatti , Gleb Natapov , LKML , KVM Subject: Re: [PATCH v2 5/5] KVM: MMU: retry #PF for softmmu References: <4CDCE2B0.7000601@cn.fujitsu.com> <4CDCE3C2.9030107@cn.fujitsu.com> <4CDFBE00.2000802@redhat.com> <4CE0C45C.809@cn.fujitsu.com> <4CE0FDBC.20505@redhat.com> In-Reply-To: <4CE0FDBC.20505@redhat.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-11-15 17:51:31, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-11-15 17:51:32, Serialize complete at 2010-11-15 17:51:32 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 Content-Length: 1120 Lines: 35 On 11/15/2010 05:30 PM, Avi Kivity wrote: >> Yeah, this 'retry' is unnecessary if the process is killed, but this >> case is infrequent, the most case is the process keeps running and try >> to access the fault address later. > > The problem is that if we retry in this case, we install an incorrect spte? > ...... >> can avoid if the page mapping have been fixed. > > The guest may have changed page directories or other levels. > ...... >> > Or another thread may have mmap()ed something else over the >> > same address. >> >> The mmap virtual address is also visible for other threads since the >> threads >> have the same page table, so i think this case is the same as above? > > Again, don't we install the wrong spte in this case? > I think it doesn't corrupts spte since we will walk guest page table again and map it to shadow pages when we retry #PF. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/