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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 F0FB1C00454 for ; Wed, 11 Dec 2019 20:49:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BDF682173E for ; Wed, 11 Dec 2019 20:49:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="iQ7kT7Y9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727433AbfLKUtN (ORCPT ); Wed, 11 Dec 2019 15:49:13 -0500 Received: from mail-pj1-f74.google.com ([209.85.216.74]:50739 "EHLO mail-pj1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727388AbfLKUtL (ORCPT ); Wed, 11 Dec 2019 15:49:11 -0500 Received: by mail-pj1-f74.google.com with SMTP id e5so12141253pjr.17 for ; Wed, 11 Dec 2019 12:49:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=WZ/pozjf2CR0qApOsQ3LoX3Js66TDlIX/9nxk8jnQ0A=; b=iQ7kT7Y9mfyXWGO8Q29hx1zTEE9Bdhpvd73jndRbpQMA/nkDSJJad1cfgRiSXcp0GG Aoll/H628y/FGWtzQgLzGiYTPKxZHoBdgVo/BXOGGxyK82U8Ult9z22hrdQEAedMOX7p HkB0IiXMVFJtsNvcvj1Hh36SQIgESTDivY0LJOzA8ia/NHpeCKbqEw4JeK9T9+3BWXHb ouPhMP0W13hDD4Zqxc0Houg9bB8OgUh3IslZQvH0jeJn9rzj0AGauJ+zGNSN9kcRKyzv DyfcNbMomWZWNMIcvWzSWqUrHQ8L9PPd6WdGWc8TVeQK5oBINUP6Fsi+0bBJNI5+ggI1 PpJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=WZ/pozjf2CR0qApOsQ3LoX3Js66TDlIX/9nxk8jnQ0A=; b=Yds7ntslXfdv531ZwnljhvyjGbNpK/fPDXOc1YtXToMUl0MXOxZ3epY9rbTy12oroP HXpCKlO5cDUYpN4gxr6Ilt8q+Wzu7fn/SEy5f4PLKHGqrA5CGn0hw9CCAlMOsarwqv9o BNHatFYq9KUdeReCFeOKc4Mn6llp7VqaPQ3/OS5oEFJ7IGAyRKG0qIzzK/23OaxZ4e9E erNv2GwZAbo1pjJHohImk2/xqKwV+aEHfjJ9AGta39FXLnqCLgxYyeaA9BXJPSZ4aiuU w83xyS9dVBe+ec2CtmGcOn3Ifo6t1ZUugotXE2owjri/JjlkJyVD7y7DYHFSQZc49igL X+uQ== X-Gm-Message-State: APjAAAUdZj5KciF2SbtvLdssaWiWov6/mID2HukWlquF/RufuY1DNlCA TONM2gIFmcyjjFcsyxdSV6MDKgTb0BwY X-Google-Smtp-Source: APXvYqxQMz+7rmle/AEYWdoD3NDtjcWQN/4YuaU56QUbmfqi9ASnXB/oWkpGs3X5CREMFPVXnKInlo10uoJH X-Received: by 2002:a63:d017:: with SMTP id z23mr6411966pgf.110.1576097350640; Wed, 11 Dec 2019 12:49:10 -0800 (PST) Date: Wed, 11 Dec 2019 12:47:52 -0800 In-Reply-To: <20191211204753.242298-1-pomonis@google.com> Message-Id: <20191211204753.242298-13-pomonis@google.com> Mime-Version: 1.0 References: <20191211204753.242298-1-pomonis@google.com> X-Mailer: git-send-email 2.24.0.525.g8f36a354ae-goog Subject: [PATCH v2 12/13] KVM: x86: Protect DR-based index computations from Spectre-v1/L1TF attacks From: Marios Pomonis To: Paolo Bonzini , rkrcmar@redhat.com, Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Nick Finco , Andrew Honig , Marios Pomonis , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This fixes a Spectre-v1/L1TF vulnerability in __kvm_set_dr() and kvm_get_dr(). Both kvm_get_dr() and kvm_set_dr() (a wrapper of __kvm_set_dr()) are exported symbols so KVM should tream them conservatively from a security perspective. Fixes: commit 020df0794f57 ("KVM: move DR register access handling into generic code") Signed-off-by: Nick Finco Signed-off-by: Marios Pomonis Reviewed-by: Andrew Honig Cc: stable@vger.kernel.org --- arch/x86/kvm/x86.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a9e66f09422e..9a2789652231 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1057,9 +1057,11 @@ static u64 kvm_dr6_fixed(struct kvm_vcpu *vcpu) static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val) { + size_t size = ARRAY_SIZE(vcpu->arch.db); + switch (dr) { case 0 ... 3: - vcpu->arch.db[dr] = val; + vcpu->arch.db[array_index_nospec(dr, size)] = val; if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) vcpu->arch.eff_db[dr] = val; break; @@ -1096,9 +1098,11 @@ EXPORT_SYMBOL_GPL(kvm_set_dr); int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val) { + size_t size = ARRAY_SIZE(vcpu->arch.db); + switch (dr) { case 0 ... 3: - *val = vcpu->arch.db[dr]; + *val = vcpu->arch.db[array_index_nospec(dr, size)]; break; case 4: /* fall through */ -- 2.24.0.525.g8f36a354ae-goog