Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756247Ab3I3VuT (ORCPT ); Mon, 30 Sep 2013 17:50:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41668 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755415Ab3I3VuR (ORCPT ); Mon, 30 Sep 2013 17:50:17 -0400 Date: Mon, 30 Sep 2013 18:23:08 -0300 From: Marcelo Tosatti To: Xiao Guangrong Cc: gleb@redhat.com, avi.kivity@gmail.com, pbonzini@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH v2 02/15] KVM: MMU: properly check last spte in fast_page_fault() Message-ID: <20130930212308.GA31805@amt.cnet> References: <1378376958-27252-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <1378376958-27252-3-git-send-email-xiaoguangrong@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1378376958-27252-3-git-send-email-xiaoguangrong@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2689 Lines: 82 On Thu, Sep 05, 2013 at 06:29:05PM +0800, Xiao Guangrong wrote: > Using sp->role.level instead of @level since @level is not got from the > page table hierarchy > > There is no issue in current code since the fast page fault currently only > fixes the fault caused by dirty-log that is always on the last level > (level = 1) > > This patch makes the code more readable and avoids potential issue in the > further development > > Signed-off-by: Xiao Guangrong > --- > arch/x86/kvm/mmu.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index 7714fd8..869f1db 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -2804,9 +2804,9 @@ static bool page_fault_can_be_fast(u32 error_code) > } > > static bool > -fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 spte) > +fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, > + u64 *sptep, u64 spte) > { > - struct kvm_mmu_page *sp = page_header(__pa(sptep)); > gfn_t gfn; > > WARN_ON(!sp->role.direct); > @@ -2832,6 +2832,7 @@ static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level, > u32 error_code) > { > struct kvm_shadow_walk_iterator iterator; > + struct kvm_mmu_page *sp; > bool ret = false; > u64 spte = 0ull; > > @@ -2852,7 +2853,8 @@ static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level, > goto exit; > } > > - if (!is_last_spte(spte, level)) > + sp = page_header(__pa(iterator.sptep)); > + if (!is_last_spte(spte, sp->role.level)) > goto exit; > > /* > @@ -2878,7 +2880,7 @@ static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level, > * the gfn is not stable for indirect shadow page. > * See Documentation/virtual/kvm/locking.txt to get more detail. > */ > - ret = fast_pf_fix_direct_spte(vcpu, iterator.sptep, spte); > + ret = fast_pf_fix_direct_spte(vcpu, sp, iterator.sptep, spte); > exit: > trace_fast_page_fault(vcpu, gva, error_code, iterator.sptep, > spte, ret); > -- > 1.8.1.4 Unrelated to this patch: If vcpu->mode = OUTSIDE_GUEST_MODE, no IPI is sent by kvm_flush_remote_tlbs. So how is this supposed to work again? /* * Wait for all vcpus to exit guest mode and/or lockless shadow * page table walks. */ kvm_flush_remote_tlbs(kvm); Patch looks fine. -- 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/