Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753359AbbEGJyC (ORCPT ); Thu, 7 May 2015 05:54:02 -0400 Received: from mga11.intel.com ([192.55.52.93]:52014 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753342AbbEGJx4 (ORCPT ); Thu, 7 May 2015 05:53:56 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,384,1427785200"; d="scan'208";a="490500086" Message-ID: <554B3570.10804@linux.intel.com> Date: Thu, 07 May 2015 17:50:40 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Paolo Bonzini CC: gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] KVM: MMU: fix smap permission check References: <1430986817-6260-1-git-send-email-guangrong.xiao@linux.intel.com> <1430986817-6260-2-git-send-email-guangrong.xiao@linux.intel.com> <554B311D.2010701@redhat.com> In-Reply-To: <554B311D.2010701@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2061 Lines: 62 On 05/07/2015 05:32 PM, Paolo Bonzini wrote: > > > On 07/05/2015 10:20, Xiao Guangrong wrote: >> Current permission check assumes that RSVD bit in PFEC is always zero, >> however, it is not true since MMIO #PF will use it to quickly identify >> MMIO access >> >> Fix it by clearing the bit if walking guest page table is needed >> >> Signed-off-by: Xiao Guangrong >> --- >> arch/x86/kvm/mmu.h | 2 ++ >> arch/x86/kvm/paging_tmpl.h | 7 +++++++ >> 2 files changed, 9 insertions(+) >> >> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h >> index c7d6563..06eb2fc 100644 >> --- a/arch/x86/kvm/mmu.h >> +++ b/arch/x86/kvm/mmu.h >> @@ -166,6 +166,8 @@ static inline bool permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, >> int index = (pfec >> 1) + >> (smap >> (X86_EFLAGS_AC_BIT - PFERR_RSVD_BIT + 1)); >> >> + WARN_ON(pfec & PFERR_RSVD_MASK); >> + >> return (mmu->permissions[index] >> pte_access) & 1; >> } >> >> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h >> index fd49c86..6e6d115 100644 >> --- a/arch/x86/kvm/paging_tmpl.h >> +++ b/arch/x86/kvm/paging_tmpl.h >> @@ -718,6 +718,13 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code, >> mmu_is_nested(vcpu)); >> if (likely(r != RET_MMIO_PF_INVALID)) >> return r; >> + >> + /* >> + * page fault with PFEC.RSVD = 1 is caused by shadow >> + * page fault, should not be used to walk guest page >> + * table. >> + */ >> + error_code &= ~PFERR_RSVD_MASK; >> }; >> >> r = mmu_topup_memory_caches(vcpu); >> > > Applied. > > For the other patches I'm waiting for an answer re. kvm_mmu_pte_write. Sure. Actually, i noticed these bugs when i was reviewing your patches, will continue to review soon. :) -- 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/