From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: Re: [PATCH v2] KVM MMU: check reserved bits only when CR4.PSE=1 or CR4.PAE=1 Date: Thu, 18 Mar 2010 19:30:15 +0800 Message-ID: <4BA20EC7.5070508@cn.fujitsu.com> References: <4BA04FCA.40308@cn.fujitsu.com> <20100318024948.GB23995@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Avi Kivity , Sheng Yang , KVM list , LKML To: Marcelo Tosatti Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:59277 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752808Ab0CRLcQ (ORCPT ); Thu, 18 Mar 2010 07:32:16 -0400 In-Reply-To: <20100318024948.GB23995@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: Hi Marcelo, Thanks for your review. Marcelo Tosatti wrote: > On Wed, Mar 17, 2010 at 11:43:06AM +0800, Xiao Guangrong wrote: >> - The RSV bit is possibility set in error code when #PF occurred >> only if CR4.PSE=1 or CR4.PAE=1 >> >> - context->rsvd_bits_mask[1][0] is always 0 >> >> Changlog: >> Move this operation to reset_rsvds_bits_mask() address Avi Kivity's suggestion >> >> Signed-off-by: Xiao Guangrong >> --- >> arch/x86/kvm/mmu.c | 12 +++++++++--- >> 1 files changed, 9 insertions(+), 3 deletions(-) >> >> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c >> index b137515..c49f8ec 100644 >> --- a/arch/x86/kvm/mmu.c >> +++ b/arch/x86/kvm/mmu.c >> @@ -2288,18 +2288,26 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, int level) >> >> if (!is_nx(vcpu)) >> exb_bit_rsvd = rsvd_bits(63, 63); >> + >> + context->rsvd_bits_mask[1][0] = 0; > > So if the guest enables PAT at PTE level you completly disable reserved > bit checking? You should only disable checking for [1][1] if !PSE. Sorry, i make a mistake here because i see the current code is redundant: context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[1][0]; in every case. This code is imported by commit fd2e987d, i think this is Avi Kivity's typo :-) i think the correct way is: ontext->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0]; I'll send a new version patch to fix it if you not object. Xiao