From owner-svn-src-all@freebsd.org Wed Jan 31 14:56:29 2018 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C8D11ECFAE6; Wed, 31 Jan 2018 14:56:29 +0000 (UTC) (envelope-from bzeeb-lists@lists.zabbadoz.net) Received: from mx1.sbone.de (mx1.sbone.de [IPv6:2a01:4f8:130:3ffc::401:25]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client CN "mx1.sbone.de", Issuer "SBone.DE" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 537498734A; Wed, 31 Jan 2018 14:56:29 +0000 (UTC) (envelope-from bzeeb-lists@lists.zabbadoz.net) Received: from mail.sbone.de (mail.sbone.de [IPv6:fde9:577b:c1a9:31::2013:587]) (using TLSv1 with cipher ADH-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mx1.sbone.de (Postfix) with ESMTPS id 651DF25D385E; Wed, 31 Jan 2018 14:56:27 +0000 (UTC) Received: from content-filter.sbone.de (content-filter.sbone.de [IPv6:fde9:577b:c1a9:31::2013:2742]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.sbone.de (Postfix) with ESMTPS id B4085D1F835; Wed, 31 Jan 2018 14:56:26 +0000 (UTC) X-Virus-Scanned: amavisd-new at sbone.de Received: from mail.sbone.de ([IPv6:fde9:577b:c1a9:31::2013:587]) by content-filter.sbone.de (content-filter.sbone.de [fde9:577b:c1a9:31::2013:2742]) (amavisd-new, port 10024) with ESMTP id zGzNSg4DIG4A; Wed, 31 Jan 2018 14:56:25 +0000 (UTC) Received: from [10.248.101.31] (fresh-ayiya.sbone.de [IPv6:fde9:577b:c1a9:f001::2]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.sbone.de (Postfix) with ESMTPSA id 33913D1F834; Wed, 31 Jan 2018 14:56:25 +0000 (UTC) From: "Bjoern A. Zeeb" To: "Konstantin Belousov" Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r328625 - in head/sys: amd64/amd64 amd64/ia32 amd64/include dev/cpuctl i386/i386 x86/include x86/x86 Date: Wed, 31 Jan 2018 14:56:24 +0000 X-Mailer: MailMate (2.0BETAr6103) Message-ID: In-Reply-To: <201801311436.w0VEaRrZ030839@repo.freebsd.org> References: <201801311436.w0VEaRrZ030839@repo.freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 31 Jan 2018 14:56:30 -0000 On 31 Jan 2018, at 14:36, Konstantin Belousov wrote: > Author: kib > Date: Wed Jan 31 14:36:27 2018 > New Revision: 328625 > URL: https://svnweb.freebsd.org/changeset/base/328625 > > Log: > IBRS support, AKA Spectre hardware mitigation. > For existing processors, you need a microcode update which adds IBRS > CPU features, and to manually enable it by setting the > tunable/sysctl > hw.ibrs_disable to 0. Current status can be checked in sysctl > hw.ibrs_active. The mitigation might be inactive if the CPU feature Can you change the tunable/sysctl to hw.ibrs_enable[d] (and toggle the default setting along). I find it highly confusing to have two different sysctls “disable” and “active” and a lot of people (and cultures) have trouble with the double negative. Also the “enable[d]” variant seems to be pre-dominant in the kernel. Also can we spell IBRS in the sysctl description as “Indirect Branch Restricted Speculation (IBRS)”? Thanks /bz