From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755977Ab0IBQdm (ORCPT ); Thu, 2 Sep 2010 12:33:42 -0400 Received: from tx2ehsobe002.messaging.microsoft.com ([65.55.88.12]:57993 "EHLO TX2EHSOBE004.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755917Ab0IBQdk (ORCPT ); Thu, 2 Sep 2010 12:33:40 -0400 X-SpamScore: -36 X-BigFish: VS-36(zzbb2dK1432N98dN4015L9371Pzz1202hzz15d4Rz32i87h2a8h61h) X-Spam-TCS-SCL: 0:0 X-FB-DOMAIN-IP-MATCH: fail X-WSS-ID: 0L84OLN-02-CN7-02 X-M-MSG: Date: Thu, 2 Sep 2010 18:32:20 +0200 From: "Roedel, Joerg" To: Avi Kivity CC: Marcelo Tosatti , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/3] KVM: MMU: Fix 32 bit legacy paging with NPT Message-ID: <20100902163220.GE1964@amd.com> References: <1283441387-7378-1-git-send-email-joerg.roedel@amd.com> <1283441387-7378-2-git-send-email-joerg.roedel@amd.com> <4C7FC91A.5030305@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <4C7FC91A.5030305@redhat.com> Organization: Advanced Micro Devices =?iso-8859-1?Q?GmbH?= =?iso-8859-1?Q?=2C_Karl-Hammerschmidt-Str=2E_34=2C_85609_Dornach_bei_M=FC?= =?iso-8859-1?Q?nchen=2C_Gesch=E4ftsf=FChrer=3A_Thomas_M=2E_McCoy=2C_Giuli?= =?iso-8859-1?Q?ano_Meroni=2C_Andrew_Bowd=2C_Sitz=3A_Dornach=2C_Gemeinde_A?= =?iso-8859-1?Q?schheim=2C_Landkreis_M=FCnchen=2C_Registergericht_M=FCnche?= =?iso-8859-1?Q?n=2C?= HRB Nr. 43632 User-Agent: Mutt/1.5.20 (2009-06-14) X-Reverse-DNS: ausb3extmailp02.amd.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 02, 2010 at 11:56:10AM -0400, Avi Kivity wrote: > On 09/02/2010 06:29 PM, Joerg Roedel wrote: > > This patch fixes 32 bit legacy paging with NPT enabled. The > > mmu_check_root call on the top-level of the loop causes > > root_gfn to take values (in the tdp_enabled path) which are > > outside of guest memory. So the mmu_check_root call fails at > > some point in the loop interation causing the guest to > > tiple-fault. > > This patch changes the mmu_check_root calls to the places > > where they are really necessary. As a side-effect it > > introduces a check for the root of a pae page table too. > > > > > > @@ -2387,6 +2387,10 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu) > > return 0; > > } > > direct = !is_paging(vcpu); > > + > > + if (mmu_check_root(vcpu, root_gfn)) > > + return 1; > > + > > for (i = 0; i< 4; ++i) { > > hpa_t root = vcpu->arch.mmu.pae_root[i]; > > > > @@ -2398,10 +2402,10 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu) > > continue; > > } > > root_gfn = pdptr>> PAGE_SHIFT; > > + if (mmu_check_root(vcpu, root_gfn)) > > + return 1; > > } else if (vcpu->arch.mmu.root_level == 0) > > root_gfn = 0; > > - if (mmu_check_root(vcpu, root_gfn)) > > - return 1; > > if (tdp_enabled) { > > direct = 1; > > root_gfn = i<< 30; > > The overloading of root_gfn is pretty bad. Also, we don't really need > to check root_gfn for the direct case (the guest can easily switch cr3 > later to one that would fail the check). > > However, I'll apply the patch since it fixes the direct problem. More > involved fixes can come later (esp. after the nnpt patches land). Ok, great. I will rebase my nnpt patches on-top of this and do some more final testing before I post them. Thanks, Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632