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=-9.1 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_PASS,USER_AGENT_GIT 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 108C8C04AA7 for ; Mon, 13 May 2019 14:39:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D5D3E2084A for ; Mon, 13 May 2019 14:39:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="g5WaOGjM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730178AbfEMOjf (ORCPT ); Mon, 13 May 2019 10:39:35 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:59240 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730136AbfEMOjd (ORCPT ); Mon, 13 May 2019 10:39:33 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x4DESr12184826; Mon, 13 May 2019 14:38:48 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2018-07-02; bh=03NJAuy8gQRMw5NMdO5oIpncwVrdcNhEn/qnXsnIh+Q=; b=g5WaOGjMCQGcw3yFQID9Xz5SR+orOYV1jEvqta9pP1dW+3vk6S7rk3Xf0Xqs9c72Ro1w /TCodkQB+5Z4YQjeExvs0QvsKAbjAzfxUXW21GiZ7ZoPR7nSWQ/5N76ENeSlLIaBPOuq oraTRR4s8rulSGRtJmfzQ6I6tr45ficozvt9Zf9IR0tS1V0R/j/qCwAykrzu4TBWku12 vyAVK6nNFxTgtyozBfwL3irrf/S3fPxxNjChwJoT7jqQ+3BTuw9SWcfOTckw2b1l05Nd oG/FOBhG00v9BsVeDYzcuV3eTXQRhjHKRHxD7Luw1u+N5LvXr+eEUi8yT9Gj8XmE4JX0 Bg== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2120.oracle.com with ESMTP id 2sdq1q7aqq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 13 May 2019 14:38:48 +0000 Received: from achartre-desktop.fr.oracle.com (dhcp-10-166-106-34.fr.oracle.com [10.166.106.34]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id x4DEcZQ5022780; Mon, 13 May 2019 14:38:45 GMT From: Alexandre Chartre To: pbonzini@redhat.com, rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, kvm@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: konrad.wilk@oracle.com, jan.setjeeilers@oracle.com, liran.alon@oracle.com, jwadams@google.com, alexandre.chartre@oracle.com Subject: [RFC KVM 02/27] KVM: x86: Introduce address_space_isolation module parameter Date: Mon, 13 May 2019 16:38:10 +0200 Message-Id: <1557758315-12667-3-git-send-email-alexandre.chartre@oracle.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1557758315-12667-1-git-send-email-alexandre.chartre@oracle.com> References: <1557758315-12667-1-git-send-email-alexandre.chartre@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9255 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905130102 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Liran Alon Add the address_space_isolation parameter to the kvm module. When set to true, KVM #VMExit handlers run in isolated address space which maps only KVM required code and per-VM information instead of entire kernel address space. This mechanism is meant to mitigate memory-leak side-channels CPU vulnerabilities (e.g. Spectre, L1TF and etc.) but can also be viewed as security in-depth as it also helps generically against info-leaks vulnerabilities in KVM #VMExit handlers and reduce the available gadgets for ROP attacks. This is set to false by default because it incurs a performance hit which some users will not want to take for security gain. Signed-off-by: Liran Alon Signed-off-by: Alexandre Chartre --- arch/x86/kvm/Makefile | 2 +- arch/x86/kvm/isolation.c | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletions(-) create mode 100644 arch/x86/kvm/isolation.c diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile index 31ecf7a..9f404e9 100644 --- a/arch/x86/kvm/Makefile +++ b/arch/x86/kvm/Makefile @@ -10,7 +10,7 @@ kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o kvm-y += x86.o mmu.o emulate.o i8259.o irq.o lapic.o \ i8254.o ioapic.o irq_comm.o cpuid.o pmu.o mtrr.o \ - hyperv.o page_track.o debugfs.o + hyperv.o page_track.o debugfs.o isolation.o kvm-intel-y += vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o vmx/evmcs.o vmx/nested.o kvm-amd-y += svm.o pmu_amd.o diff --git a/arch/x86/kvm/isolation.c b/arch/x86/kvm/isolation.c new file mode 100644 index 0000000..e25f663 --- /dev/null +++ b/arch/x86/kvm/isolation.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + * + * KVM Address Space Isolation + */ + +#include +#include + +/* + * When set to true, KVM #VMExit handlers run in isolated address space + * which maps only KVM required code and per-VM information instead of + * entire kernel address space. + * + * This mechanism is meant to mitigate memory-leak side-channels CPU + * vulnerabilities (e.g. Spectre, L1TF and etc.) but can also be viewed + * as security in-depth as it also helps generically against info-leaks + * vulnerabilities in KVM #VMExit handlers and reduce the available + * gadgets for ROP attacks. + * + * This is set to false by default because it incurs a performance hit + * which some users will not want to take for security gain. + */ +static bool __read_mostly address_space_isolation; +module_param(address_space_isolation, bool, 0444); -- 1.7.1