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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 BD3EEC10DCE for ; Wed, 18 Mar 2020 18:40:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FBE02077F for ; Wed, 18 Mar 2020 18:40:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="OlTrfFpz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726781AbgCRSkV (ORCPT ); Wed, 18 Mar 2020 14:40:21 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:46722 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726506AbgCRSkV (ORCPT ); Wed, 18 Mar 2020 14:40:21 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 02IIcn3A042181; Wed, 18 Mar 2020 18:40:17 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=sLjVWZvpMwWx2eXCxBSd4lEA29TaEzJvkHaAr3aH71E=; b=OlTrfFpzt3wNpk/1TwUZrjzjw/A6/Py5RD/7zvESyQEJsQPI/2sVmo0WrxFhINidH4DS p3ghzipq54NeyAjgm7G3LgstyyHx5nNqdCQUOdFY7KHI6rzZxOCJ961l0vS8WS+omfvy DaOZw4Ui1QLXfD+xDsa/3KMuCDKdWixwIQD8YEb7y2dlI+aiV5qrdl+ThYKyTAc59zl3 +BdT8shtqFTshogdL5lRw47YfoY2prAD5WhviY8Ugx5BVjpSU0cPVfHJuLgLYBBB+56N UW5ap7rhG/8UGmb1H90TlY5orXhfUDykYtvBcn8uYRa4d/27ok8A0p+EY4kK0VHHgeb4 oA== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by aserp2120.oracle.com with ESMTP id 2yrq7m49pf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 18 Mar 2020 18:40:17 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 02IIbe4b053965; Wed, 18 Mar 2020 18:40:16 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3020.oracle.com with ESMTP id 2ys92has9y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 18 Mar 2020 18:40:16 +0000 Received: from abhmp0007.oracle.com (abhmp0007.oracle.com [141.146.116.13]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 02IIeFAQ020988; Wed, 18 Mar 2020 18:40:15 GMT Received: from localhost.localdomain (/10.159.130.178) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 18 Mar 2020 11:40:15 -0700 Subject: Re: [PATCH] KVM: nSVM: check for EFER.SVME=1 before entering guest To: Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org References: <1584535300-6571-1-git-send-email-pbonzini@redhat.com> From: Krish Sadhukhan Message-ID: Date: Wed, 18 Mar 2020 11:40:07 -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: <1584535300-6571-1-git-send-email-pbonzini@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=9564 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 mlxlogscore=999 mlxscore=0 spamscore=0 bulkscore=0 adultscore=0 suspectscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003180083 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9564 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 lowpriorityscore=0 suspectscore=0 adultscore=0 bulkscore=0 mlxlogscore=999 priorityscore=1501 clxscore=1015 malwarescore=0 mlxscore=0 phishscore=0 impostorscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003180083 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/18/20 5:41 AM, Paolo Bonzini wrote: > EFER is set for L2 using svm_set_efer, which hardcodes EFER_SVME to 1 and hides > an incorrect value for EFER.SVME in the L1 VMCB. Perform the check manually > to detect invalid guest state. > > Reported-by: Krish Sadhukhan > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/svm.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index 08568ae9f7a1..2125c6ae5951 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -3558,6 +3558,9 @@ static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm) > > static bool nested_vmcb_checks(struct vmcb *vmcb) > { > + if ((vmcb->save.efer & EFER_SVME) == 0) > + return false; > + > if ((vmcb->control.intercept & (1ULL << INTERCEPT_VMRUN)) == 0) > return false; > Ah! This now tells me that I forgot the KVM fix that was supposed to accompany my patchset. Do we need this check in software ? I wasn't checking the bit in KVM and instead I was just making sure that L0 sets that bit based on the setting in nested vmcb: +static void nested_svm_set_efer(struct kvm_vcpu *vcpu, u64 nested_vmcb_efer) +{ +       svm_set_efer(vcpu, nested_vmcb_efer); + +       if (!(nested_vmcb_efer & EFER_SVME)) +               to_svm(vcpu)->vmcb->save.efer &= ~EFER_SVME; +} +  static int is_external_interrupt(u32 info)  {         info &= SVM_EVTINJ_TYPE_MASK | SVM_EVTINJ_VALID; @@ -3554,7 +3562,7 @@ static void enter_svm_guest_mode(struct vcpu_svm *svm, u64         svm->vmcb->save.gdtr = nested_vmcb->save.gdtr;         svm->vmcb->save.idtr = nested_vmcb->save.idtr;         kvm_set_rflags(&svm->vcpu, nested_vmcb->save.rflags); -       svm_set_efer(&svm->vcpu, nested_vmcb->save.efer); +       nested_svm_set_efer(&svm->vcpu, nested_vmcb->save.efer);         svm_set_cr0(&svm->vcpu, nested_vmcb->save.cr0);         svm_set_cr4(&svm->vcpu, nested_vmcb->save.cr4);         if (npt_enabled) {