From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31253C433E0 for ; Wed, 8 Jul 2020 22:51:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A09220775 for ; Wed, 8 Jul 2020 22:51:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="soCTzsKO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726081AbgGHWvp (ORCPT ); Wed, 8 Jul 2020 18:51:45 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:50538 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725915AbgGHWvo (ORCPT ); Wed, 8 Jul 2020 18:51:44 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 068Mflak068904; Wed, 8 Jul 2020 22:51:41 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2020-01-29; bh=UEpeaDjIvSEtNuvTS9MBJY5BQklHwnKoPYJI2+et9vY=; b=soCTzsKOrNk/WjXoUPQTlJgHaOotWrNJgbtCsy2AUEkwLeSZJw0s0OCxacG694Binupq UZHJ5noWBzjEHwC5YuRJbLxsd5yTn6ekWNCwdiMu5olUo6d0vG5yUJ54yPX/EMjoTLBp nzTNKopLhMtWQy3wlo4DnS5byWQkjBmCgh1qJE2Z34XREIdimuadW6PkspPckWdr7YBM awAHArYVYT0MrqN927a74CFTu/Co/YQg538bXOASFRXsS53iaZgwSgv2uSKRJDvjxbJA HA8lIuxD8LDAJL/sr3+91/n4yhzKHRlFB+jdruDUp3bxq8xFJ21zsALo7OQiaAUjPkXx eg== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 325k2w1a7s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 08 Jul 2020 22:51:41 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 068MhFWZ044389; Wed, 8 Jul 2020 22:51:41 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 325k3fub4d-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 08 Jul 2020 22:51:40 +0000 Received: from abhmp0001.oracle.com (abhmp0001.oracle.com [141.146.116.7]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 068MpdFB009142; Wed, 8 Jul 2020 22:51:39 GMT Received: from localhost.localdomain (/10.159.144.146) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 08 Jul 2020 15:51:39 -0700 Subject: Re: [PATCH 2/3 v4] KVM: nSVM: Check that MBZ bits in CR3 and CR4 are not set on vmrun of nested guests To: Paolo Bonzini , kvm@vger.kernel.org References: <1594168797-29444-1-git-send-email-krish.sadhukhan@oracle.com> <1594168797-29444-3-git-send-email-krish.sadhukhan@oracle.com> <699b4ea4-d8df-e098-8f5c-3abe8e4c138c@redhat.com> From: Krish Sadhukhan Message-ID: Date: Wed, 8 Jul 2020 15:51:38 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <699b4ea4-d8df-e098-8f5c-3abe8e4c138c@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9676 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 phishscore=0 mlxlogscore=999 bulkscore=0 spamscore=0 mlxscore=0 adultscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007080137 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9676 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 phishscore=0 impostorscore=0 mlxscore=0 clxscore=1015 mlxlogscore=999 malwarescore=0 lowpriorityscore=0 adultscore=0 priorityscore=1501 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007080137 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 7/8/20 3:03 AM, Paolo Bonzini wrote: > On 08/07/20 02:39, Krish Sadhukhan wrote: >> +extern int kvm_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4); >> + > This should be added in x86.h, not here. > >> +static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb) >> { >> if ((vmcb->save.efer & EFER_SVME) == 0) >> return false; >> @@ -231,6 +233,22 @@ static bool nested_vmcb_checks(struct vmcb *vmcb) >> (vmcb->save.cr0 & X86_CR0_NW)) >> return false; >> >> + if (!is_long_mode(&(svm->vcpu))) { >> + if (vmcb->save.cr4 & X86_CR4_PAE) { >> + if (vmcb->save.cr3 & MSR_CR3_LEGACY_PAE_RESERVED_MASK) >> + return false; >> + } else { >> + if (vmcb->save.cr3 & MSR_CR3_LEGACY_RESERVED_MASK) >> + return false; >> + } >> + } else { >> + if ((vmcb->save.cr4 & X86_CR4_PAE) && >> + (vmcb->save.cr3 & MSR_CR3_LONG_RESERVED_MASK)) >> + return false; >> + } > is_long_mode here is wrong, as it refers to the host. > > You need to do something like this: > > diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c > index 385461496cf5..cbbab83f19cc 100644 > --- a/arch/x86/kvm/svm/nested.c > +++ b/arch/x86/kvm/svm/nested.c > @@ -222,8 +222,9 @@ static bool nested_vmcb_check_controls(struct vmcb_control_area *control) > return true; > } > > -static bool nested_vmcb_checks(struct vmcb *vmcb) > +static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb) > { > + bool nested_vmcb_lma; > if ((vmcb->save.efer & EFER_SVME) == 0) > return false; > > @@ -234,6 +237,27 @@ static bool nested_vmcb_checks(struct vmcb *vmcb) > if (!kvm_dr6_valid(vmcb->save.dr6) || !kvm_dr7_valid(vmcb->save.dr7)) > return false; > > + nested_vmcb_lma = > + (vmcb->save.efer & EFER_LME) && Just curious about using LME instead of LMA. According to APM,     " The processor behaves as a 32-bit x86 processor in all respects until long mode is activated, even if long mode is enabled. None of the new 64-bit data sizes, addressing, or system aspects available in long mode can be used until EFER.LMA=1." Is it possible that L1 sets LME, but not LMA, in L2's  VMCS and this code will execute even if the processor is not in long-mode ? > + (vmcb->save.cr0 & X86_CR0_PG); > + > + if (!nested_vmcb_lma) { > + if (vmcb->save.cr4 & X86_CR4_PAE) { > + if (vmcb->save.cr3 & MSR_CR3_LEGACY_PAE_RESERVED_MASK) > + return false; > + } else { > + if (vmcb->save.cr3 & MSR_CR3_LEGACY_RESERVED_MASK) > + return false; > + } > + } else { > + if (!(vmcb->save.cr4 & X86_CR4_PAE) || > + !(vmcb->save.cr0 & X86_CR0_PE) || > + (vmcb->save.cr3 & MSR_CR3_LONG_RESERVED_MASK)) > + return false; > + } > + if (kvm_valid_cr4(&(svm->vcpu), vmcb->save.cr4)) > + return false; > + > return nested_vmcb_check_controls(&vmcb->control); > } > > which also takes care of other CR0/CR4 checks in the APM. > > I'll test this a bit more and queue it. Are you also going to add > more checks in svm_set_nested_state? > > Paolo >