From mboxrd@z Thu Jan 1 00:00:00 1970 From: "tiejun.chen" Subject: Re: [v1][PATCH 1/1] kvm:ppc:booehv: direct ISI exception to Guest Date: Thu, 9 May 2013 18:23:15 +0800 Message-ID: <518B7913.6010302@windriver.com> References: <1367970043.3398.39@snotra> <5189B02E.3000109@windriver.com> <300B73AA675FCE4A93EB4FC1D42459FF3EFA26@039-SN2MPN1-013.039d.mgd.msft.net> <518A1AD8.3090103@windriver.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Cc: Wood Scott-B07421 , "linuxppc-dev@lists.ozlabs.org" , "agraf@suse.de" , "kvm-ppc@vger.kernel.org" , "kvm@vger.kernel.org" To: Caraman Mihai Claudiu-B02008 Return-path: Received: from mail.windriver.com ([147.11.1.11]:42177 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753237Ab3EIKX3 (ORCPT ); Thu, 9 May 2013 06:23:29 -0400 In-Reply-To: <518A1AD8.3090103@windriver.com> Sender: kvm-owner@vger.kernel.org List-ID: On 05/08/2013 05:28 PM, tiejun.chen wrote: > On 05/08/2013 05:20 PM, Caraman Mihai Claudiu-B02008 wrote: >>> -----Original Message----- >>> From: kvm-owner@vger.kernel.org [mailto:kvm-owner@vger.kernel.org] On >>> Behalf Of tiejun.chen >>> Sent: Wednesday, May 08, 2013 4:54 AM >>> To: Wood Scott-B07421 >>> Cc: agraf@suse.de; kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; >>> linuxppc-dev@lists.ozlabs.org >>> Subject: Re: [v1][KVM][PATCH 1/1] kvm:ppc:booehv: direct ISI exception to >>> Guest >>> >>> On 05/08/2013 07:40 AM, Scott Wood wrote: >>>> On 05/07/2013 06:06:30 AM, Tiejun Chen wrote: >>>>> We also can direct ISI exception to Guest like DSI. >>>>> >>>>> Signed-off-by: Tiejun Chen >>>>> --- >>>>> arch/powerpc/kvm/booke_emulate.c | 3 +++ >>>>> arch/powerpc/kvm/e500mc.c | 3 ++- >>>>> 2 files changed, 5 insertions(+), 1 deletion(-) >>>> >>>> Are you seeing a real performance improvement from this? This will >>> interfere >>> >>> No. But after we reduce the exit to host, shouldn't this improve >>> performance? >> >> We lose some flexibility for this so it make sense only if we gain >> measurable improvements. > > Sounds we have much more works to do. > >> >>> >>>> somewhat with using the VF bit, if we were to ever do so, since VF only >>> affects >>> >>> Sorry, what is the VF you said? >> >> VF stands for virtualization fault see MAS8[VF] and we may use it for virtualized > > I almost forget this point :) Looks KVM PPC have no this mechanism currently since I don't find MAS8_VF is used in kernel, right? If I'm missing something please correct me. Tiejun > >> MMIO. The hypervisor should deny execute access on pages marked with VF. >> Accordingly >> in this case guest ISI exceptions should be handled by the hypervisor. >