Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752211Ab0K3N3W (ORCPT ); Tue, 30 Nov 2010 08:29:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37442 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750925Ab0K3N3U (ORCPT ); Tue, 30 Nov 2010 08:29:20 -0500 Date: Tue, 30 Nov 2010 15:29:15 +0200 From: Gleb Natapov To: Xiao Guangrong Cc: Avi Kivity , Marcelo Tosatti , LKML , KVM Subject: Re: [PATCH v3 2/3] KVM: MMU: fix accessed bit set on prefault path Message-ID: <20101130132915.GG2187@redhat.com> References: <4CF4C535.8080405@cn.fujitsu.com> <4CF4C587.7080000@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CF4C587.7080000@cn.fujitsu.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3994 Lines: 103 On Tue, Nov 30, 2010 at 05:36:07PM +0800, Xiao Guangrong wrote: > Retry #PF is the speculative path, so don't set the accessed bit, > especially, stop prefault if shadow_accessed_mask = 0 > > Signed-off-by: Xiao Guangrong > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/mmu.c | 12 +++++++----- > arch/x86/kvm/x86.c | 3 +++ > 3 files changed, 11 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index a4c5352..209da89 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -632,6 +632,7 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes, > u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn); > > extern bool tdp_enabled; > +extern u64 __read_mostly shadow_accessed_mask; > > enum emulation_result { > EMULATE_DONE, /* no further processing */ > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index 5b71415..f34987d 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -199,8 +199,8 @@ static u64 __read_mostly shadow_notrap_nonpresent_pte; > static u64 __read_mostly shadow_nx_mask; > static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */ > static u64 __read_mostly shadow_user_mask; > -static u64 __read_mostly shadow_accessed_mask; > static u64 __read_mostly shadow_dirty_mask; > +u64 __read_mostly shadow_accessed_mask; > > static inline u64 rsvd_bits(int s, int e) > { > @@ -2214,7 +2214,8 @@ static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep) > } > > static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write, > - int map_writable, int level, gfn_t gfn, pfn_t pfn) > + int map_writable, int level, gfn_t gfn, pfn_t pfn, > + bool prefault) > { > struct kvm_shadow_walk_iterator iterator; > struct kvm_mmu_page *sp; > @@ -2229,7 +2230,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write, > pte_access &= ~ACC_WRITE_MASK; > mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, pte_access, > 0, write, 1, &pt_write, > - level, gfn, pfn, false, map_writable); > + level, gfn, pfn, prefault, map_writable); > direct_pte_prefetch(vcpu, iterator.sptep); > ++vcpu->stat.pf_fixed; > break; > @@ -2321,7 +2322,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn, > if (mmu_notifier_retry(vcpu, mmu_seq)) > goto out_unlock; > kvm_mmu_free_some_pages(vcpu); > - r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn); > + r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn, > + prefault); > spin_unlock(&vcpu->kvm->mmu_lock); > > > @@ -2683,7 +2685,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code, > goto out_unlock; > kvm_mmu_free_some_pages(vcpu); > r = __direct_map(vcpu, gpa, write, map_writable, > - level, gfn, pfn); > + level, gfn, pfn, prefault); > spin_unlock(&vcpu->kvm->mmu_lock); > > return r; > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 410d2d1..83ed55f 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -6178,6 +6178,9 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) > { > int r; > > + if (!shadow_accessed_mask) > + return; > + I don't get this. As far as I can see VMX inits shadow_accessed_mask to be zero if ept is enabled. This line here means that we never prefault with ept enabled. It is opposite from what it should be. > if (!vcpu->arch.mmu.direct_map || !work->arch.direct_map || > is_error_page(work->page)) > return; > -- > 1.7.0.4 -- Gleb. -- 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/