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=-9.9 required=3.0 tests=BAYES_00,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 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 80F88C388F7 for ; Thu, 5 Nov 2020 00:26:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 24B8F206DC for ; Thu, 5 Nov 2020 00:26:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="DEVDRcJ2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732848AbgKEAYo (ORCPT ); Wed, 4 Nov 2020 19:24:44 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:28107 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728323AbgKEAOR (ORCPT ); Wed, 4 Nov 2020 19:14:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604535255; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WgNzPrMRWMTkptqOa05ejOci8goRgD8ij+h1kCV7zHo=; b=DEVDRcJ2OJJ1Fj5C432+51FWBKZUWSWYTMrXI8BlzhDC3u2b4e3kpHtXO1g2hLdMva3tHK wLulOJJ5eO/tEGIC0uG29l8Hb3RI7pgbEssTWXHENgFpGS/5kVfnQ74IgZ6TZleGGEoRTu 44nzSx8WRsy7fjMrZQBk/qG1USMF1Ug= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-244-ex9LEUj8M7ub4_d0L-DgDQ-1; Wed, 04 Nov 2020 19:14:13 -0500 X-MC-Unique: ex9LEUj8M7ub4_d0L-DgDQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2481C10082E8; Thu, 5 Nov 2020 00:14:11 +0000 (UTC) Received: from mail (ovpn-116-241.rdu2.redhat.com [10.10.116.241]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B3E1D1007600; Thu, 5 Nov 2020 00:14:06 +0000 (UTC) From: Andrea Arcangeli To: Thomas Gleixner Cc: YiFei Zhu , Linux Containers , YiFei Zhu , bpf , kernel list , Aleksa Sarai , Andy Lutomirski , David Laight , Dimitrios Skarlatos , Giuseppe Scrivano , Hubertus Franke , Jack Chen , Jann Horn , Josep Torrellas , Tianyin Xu , Tobin Feldman-Fitzthum , Tycho Andersen , Valentin Rothberg , Will Drewry , Jiri Kosina , Waiman Long , Josh Poimboeuf , Andi Kleen Subject: [PATCH 1/1] x86: deduplicate the spectre_v2_user documentation Date: Wed, 4 Nov 2020 19:14:06 -0500 Message-Id: <20201105001406.13005-2-aarcange@redhat.com> In-Reply-To: <20201105001406.13005-1-aarcange@redhat.com> References: <20201104234047.GA18850@redhat.com> <20201105001406.13005-1-aarcange@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org This would need updating to make prctl be the new default, but it's simpler to delete it and refer to the dup. Signed-off-by: Andrea Arcangeli --- Documentation/admin-guide/hw-vuln/spectre.rst | 51 +------------------ 1 file changed, 2 insertions(+), 49 deletions(-) diff --git a/Documentation/admin-guide/hw-vuln/spectre.rst b/Documentation/admin-guide/hw-vuln/spectre.rst index 19b897cb1d45..ab7d402c1677 100644 --- a/Documentation/admin-guide/hw-vuln/spectre.rst +++ b/Documentation/admin-guide/hw-vuln/spectre.rst @@ -593,61 +593,14 @@ kernel command line. Not specifying this option is equivalent to spectre_v2=auto. -For user space mitigation: - - spectre_v2_user= - - [X86] Control mitigation of Spectre variant 2 - (indirect branch speculation) vulnerability between - user space tasks - - on - Unconditionally enable mitigations. Is - enforced by spectre_v2=on - - off - Unconditionally disable mitigations. Is - enforced by spectre_v2=off - - prctl - Indirect branch speculation is enabled, - but mitigation can be enabled via prctl - per thread. The mitigation control state - is inherited on fork. - - prctl,ibpb - Like "prctl" above, but only STIBP is - controlled per thread. IBPB is issued - always when switching between different user - space processes. - - seccomp - Same as "prctl" above, but all seccomp - threads will enable the mitigation unless - they explicitly opt out. - - seccomp,ibpb - Like "seccomp" above, but only STIBP is - controlled per thread. IBPB is issued - always when switching between different - user space processes. - - auto - Kernel selects the mitigation depending on - the available CPU features and vulnerability. - - Default mitigation: - If CONFIG_SECCOMP=y then "seccomp", otherwise "prctl" - - Not specifying this option is equivalent to - spectre_v2_user=auto. - In general the kernel by default selects reasonable mitigations for the current CPU. To disable Spectre variant 2 mitigations, boot with spectre_v2=off. Spectre variant 1 mitigations cannot be disabled. +For spectre_v2_user see :doc:`/admin-guide/kernel-parameters`. + Mitigation selection guide --------------------------