From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757426Ab2KZXRI (ORCPT ); Mon, 26 Nov 2012 18:17:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:9835 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754089Ab2KZXRG (ORCPT ); Mon, 26 Nov 2012 18:17:06 -0500 Date: Mon, 26 Nov 2012 20:37:12 -0200 From: Marcelo Tosatti To: Xiao Guangrong Cc: Avi Kivity , LKML , KVM Subject: Re: [PATCH 2/3] KVM: x86: let reexecute_instruction work for tdp Message-ID: <20121126223712.GA10634@amt.cnet> References: <50AAC77C.8040505@linux.vnet.ibm.com> <50AAC7CE.2050506@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50AAC7CE.2050506@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 On Tue, Nov 20, 2012 at 07:59:10AM +0800, Xiao Guangrong wrote: > Currently, reexecute_instruction refused to retry all instructions. If > nested npt is used, the emulation may be caused by shadow page, it can > be fixed by dropping the shadow page > > Signed-off-by: Xiao Guangrong > --- > arch/x86/kvm/x86.c | 14 ++++++++------ > 1 files changed, 8 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 7be8452..5fe72cc 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4469,17 +4469,19 @@ static int handle_emulation_failure(struct kvm_vcpu *vcpu) > return r; > } > > -static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t gva) > +static bool reexecute_instruction(struct kvm_vcpu *vcpu, unsigned long cr2) > { > - gpa_t gpa; > + gpa_t gpa = cr2; > pfn_t pfn; > > - if (tdp_enabled) > + if (!ACCESS_ONCE(vcpu->kvm->arch.indirect_shadow_pages)) > return false; How is indirect_shadow_pages protected? Why is ACCESS_ONCE() being used to read it? > - gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL); > - if (gpa == UNMAPPED_GVA) > - return true; /* let cpu generate fault */ > + if (!vcpu->arch.mmu.direct_map) { > + gpa = kvm_mmu_gva_to_gpa_read(vcpu, cr2, NULL); > + if (gpa == UNMAPPED_GVA) > + return true; /* let cpu generate fault */ > + } > > /* > * if emulation was due to access to shadowed page table > -- > 1.7.7.6