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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 035B4C433DF for ; Mon, 3 Aug 2020 12:34:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C980C2076B for ; Mon, 3 Aug 2020 12:34:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596458057; bh=N9pC0y8ia7HAFIP+qsQdo12QqCgv5yaYu1BWaAETZIE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SoQmJLGELSDgLZDQ96wXousWbqpZyaJL2EeXSxTiYz98cQwuk7e60e3cmx8OgDhl3 DYwIXpMGrDA7aahfehbomga8SZjwi2M3SYy3HV7q6ElNNoh7nUONs3Ba7sjHphRIjG Df9ECvmurTRki0IBECMR261exbPHo203G4fkYqd4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728871AbgHCMeN (ORCPT ); Mon, 3 Aug 2020 08:34:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:34184 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729528AbgHCMeH (ORCPT ); Mon, 3 Aug 2020 08:34:07 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3A629204EC; Mon, 3 Aug 2020 12:34:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596458046; bh=N9pC0y8ia7HAFIP+qsQdo12QqCgv5yaYu1BWaAETZIE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VBkEkNAM1C0dCe0mg/bnCkopg/XjKlAxEvnoYpJRMZs/lVC/9ISs9VaqDOA8czmIF +RPKM5FCzIbOjqUTjrgzDV+K5m3SKQbOIJ74iqk0rvd5pkb6dn9zg2qmopM+Poe2aM 0p8Sx08aXABp9vMb94xbfZ3P2tGUIwwT5ZWSU9yM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Boris Ostrovsky , Joao Martins , Paolo Bonzini , Sasha Levin Subject: [PATCH 4.14 08/51] x86/kvm: Be careful not to clear KVM_VCPU_FLUSH_TLB bit Date: Mon, 3 Aug 2020 14:19:53 +0200 Message-Id: <20200803121849.869521189@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200803121849.488233135@linuxfoundation.org> References: <20200803121849.488233135@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit 8c6de56a42e0c657955e12b882a81ef07d1d073e ] kvm_steal_time_set_preempted() may accidentally clear KVM_VCPU_FLUSH_TLB bit if it is called more than once while VCPU is preempted. This is part of CVE-2019-3016. (This bug was also independently discovered by Jim Mattson ) Signed-off-by: Boris Ostrovsky Reviewed-by: Joao Martins Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- arch/x86/kvm/x86.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 09f47c837c258..3aed03942d7d4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3075,6 +3075,9 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu) if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) return; + if (vcpu->arch.st.steal.preempted) + return; + vcpu->arch.st.steal.preempted = 1; kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime, -- 2.25.1