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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 086C7C352A3 for ; Mon, 10 Feb 2020 12:41:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CE05320733 for ; Mon, 10 Feb 2020 12:41:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338477; bh=mc6P79plUE2+NT5yHFbooruDYKFyGwJIhlDwTDoVieI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=h2X3nXYmclxpxdpCoYjV2XjRGZrIUYWXtAoYYMSH85CdeBRZPjVnOWxqm3EYiLOFq sd6dVFSdE8IQ6y9LfabJ/xsY6o8cm9I3+a74W9g1UkDKUI3SiFC6OCdiEnUco+awql hCdgVx37DDtNm85RZ0Lbm98eNUMtMxZ7pyHFglyU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729952AbgBJMlR (ORCPT ); Mon, 10 Feb 2020 07:41:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:43110 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729945AbgBJMlQ (ORCPT ); Mon, 10 Feb 2020 07:41:16 -0500 Received: from localhost (unknown [209.37.97.194]) (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 EB0CE2051A; Mon, 10 Feb 2020 12:41:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338476; bh=mc6P79plUE2+NT5yHFbooruDYKFyGwJIhlDwTDoVieI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VtNin9NdfoTPCiHdblTOpE3c1QiF54WQHoyRfyBCFv2YHVYSqsTxnFmPT9fzAgEEh qzuHGfyE8lSeIWvA3dVyO0roJPV/nRGKH6zBO+g7DBoKMJcV7pemWNlJPE7VsSGohP ICUHhDLIiJlSWDQy3lWrtR4xnS69iewU/wUiUbwQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Boris Ostrovsky , Joao Martins , Paolo Bonzini Subject: [PATCH 5.5 244/367] x86/kvm: Be careful not to clear KVM_VCPU_FLUSH_TLB bit Date: Mon, 10 Feb 2020 04:32:37 -0800 Message-Id: <20200210122446.704452861@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200210122423.695146547@linuxfoundation.org> References: <20200210122423.695146547@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 From: Boris Ostrovsky commit 8c6de56a42e0c657955e12b882a81ef07d1d073e upstream. 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: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3514,6 +3514,9 @@ static void kvm_steal_time_set_preempted if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) return; + if (vcpu->arch.st.steal.preempted) + return; + vcpu->arch.st.steal.preempted = KVM_VCPU_PREEMPTED; kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime,