Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760988AbaGRJEZ (ORCPT ); Fri, 18 Jul 2014 05:04:25 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:20992 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1754394AbaGRJEX (ORCPT ); Fri, 18 Jul 2014 05:04:23 -0400 X-IronPort-AV: E=Sophos;i="5.00,914,1396972800"; d="scan'208";a="33450965" Message-ID: <53C8E350.6040705@cn.fujitsu.com> Date: Fri, 18 Jul 2014 17:05:20 +0800 From: Tang Chen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Gleb Natapov CC: Jan Kiszka , , , , , , , Subject: Re: [PATCH v2 5/5] kvm, mem-hotplug: Do not pin apic access page in memory. References: <1404824492-30095-1-git-send-email-tangchen@cn.fujitsu.com> <1404824492-30095-6-git-send-email-tangchen@cn.fujitsu.com> <20140712080442.GH4399@minantech.com> <53C38D55.2040307@cn.fujitsu.com> <20140714145822.GK4399@minantech.com> <53C51608.4080109@web.de> <20140715120921.GT18167@minantech.com> <53C51E66.7030208@cn.fujitsu.com> <20140715124048.GU18167@minantech.com> <53C7D0DC.1020001@cn.fujitsu.com> <20140717135707.GP4399@minantech.com> In-Reply-To: <20140717135707.GP4399@minantech.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.226.99] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Gleb, On 07/17/2014 09:57 PM, Gleb Natapov wrote: > On Thu, Jul 17, 2014 at 09:34:20PM +0800, Tang Chen wrote: >> Hi Gleb, >> >> On 07/15/2014 08:40 PM, Gleb Natapov wrote: >> ...... >>>> >>>> And yes, we have the problem you said here. We can migrate the page while L2 >>>> vm is running. >>>> So I think we should enforce L2 vm to exit to L1. Right ? >>>> >>> We can request APIC_ACCESS_ADDR reload during L2->L1 vmexit emulation, so >>> if APIC_ACCESS_ADDR changes while L2 is running it will be reloaded for L1 too. >>> >> >> Sorry, I think I don't quite understand the procedure you are talking about >> here. >> >> Referring to the code, I think we have three machines: L0(host), L1 and L2. >> And we have two types of vmexit: L2->L1 and L2->L0. Right ? >> >> We are now talking about this case: L2 and L1 shares the apic page. >> >> Using patch 5/5, when apic page is migrated on L0, mmu_notifier will notify >> L1, >> and update L1's VMCS. At this time, we are in L0, not L2. Why cannot we > Using patch 5/5, when apic page is migrated on L0, mmu_notifier will notify > L1 or L2 VMCS depending on which one happens to be running right now. > If it is L1 then L2's VMCS will be updated during vmentry emulation, OK, this is easy to understand. >if it is > L2 we need to request reload during vmexit emulation to make sure L1's VMCS is > updated. > I'm a little confused here. In patch 5/5, I called make_all_cpus_request() to force all vcpus exit to host. If we are in L2, where will the vcpus exit to ? L1 or L0 ? Thanks. -- 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/