From owner-svn-src-head@freebsd.org Wed Jan 31 17:08:16 2018 Return-Path: Delivered-To: svn-src-head@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 790A3ED7427; Wed, 31 Jan 2018 17:08:16 +0000 (UTC) (envelope-from carpeddiem@gmail.com) Received: from mail-io0-x244.google.com (mail-io0-x244.google.com [IPv6:2607:f8b0:4001:c06::244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 107DE6F010; Wed, 31 Jan 2018 17:08:16 +0000 (UTC) (envelope-from carpeddiem@gmail.com) Received: by mail-io0-x244.google.com with SMTP id p188so15943011ioe.12; Wed, 31 Jan 2018 09:08:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=jTRpiLCt4Mxeezof3CvjJKkPgwf3zyxwS4VOIVGT7og=; b=BiStnEKyTCUN/PsS5hy5v0q/I2f1VFG61XchpMeAM4fx2PJib7jifrKPsv/lHG6+5W oDcMcMmhK3f6OYPlWIy4676HbhvYGXH7DA5dvpDBUN1PfeglD4xcIsoah4lHV1kxxvqp B/THfKmO92FjsWUBzp7+WF8ouPjNJIbPjWL4YrXQwRGuCNP6MMrYvx52rbVgQjogJSci bdOfV9/ImjDoNxec32jYRl388JAxqpkBTflmc/u/fzrariQ2GK7Cp/OGyaJ38dGLpaR5 0yjSFJ64PFOZL0/mfDnOH27tIi2tDR9yDl/lmAcSkIHR5ap4bWmY0mE8G+TkDVGGQiYl s7xg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=jTRpiLCt4Mxeezof3CvjJKkPgwf3zyxwS4VOIVGT7og=; b=d6Bqll+ZOmdxemGVEfyZhLTVj+LeLLizRoCvpexaVxiYD0+r8gidhc88sRBalNmauI w3GV+V1vLF80AfiM5D8h9C5N2OqzeAPdyHC6yq+7/26mGu0zPrrXQQ6etULcVrBgfWZC PfCwgjD4FFb5E8THAek/lvZ3TgFXpUpG6zAmN4lj/dI1XVpOEMvDgtEPehti0XIz36X5 SsciISRE+BuyC+DxRGDwChLSmWrQx3KR53BtK6fTYGTup179TnJ8yxUVBj3KIsChgB6U HUKzbA4W75WbxvPI8CDsSS56VunOR6faDaz/GYf1vWAW1AGk1MSCFP0xoVWS0UCfQ8pB ZXNQ== X-Gm-Message-State: AKwxytcrxPLgMNUvIOX/EuF2rXHLpnkRoQdAz0OyHYlkOzxVjeREXmJE 3SfhKKIh7fd4RFhuAMjO1mC4W1/w5gpc8gX5oCEoZA== X-Google-Smtp-Source: AH8x22713+NwI5ZUXziD3ikBrcMLLpzkNlnlX2YjoO/5TUc9knZ2K8o+NH79K8loatiteaPjU+74oUxidZh1SEiffXA= X-Received: by 10.107.201.136 with SMTP id z130mr7584523iof.257.1517418495414; Wed, 31 Jan 2018 09:08:15 -0800 (PST) MIME-Version: 1.0 Sender: carpeddiem@gmail.com Received: by 10.107.152.9 with HTTP; Wed, 31 Jan 2018 09:07:54 -0800 (PST) In-Reply-To: References: <201801311436.w0VEaRrZ030839@repo.freebsd.org> From: Ed Maste Date: Wed, 31 Jan 2018 12:07:54 -0500 X-Google-Sender-Auth: VeCstfoyFWWYv7la2cUPbgsH20w Message-ID: Subject: Re: svn commit: r328625 - in head/sys: amd64/amd64 amd64/ia32 amd64/include dev/cpuctl i386/i386 x86/include x86/x86 To: "Bjoern A. Zeeb" Cc: Konstantin Belousov , src-committers , svn-src-all@freebsd.org, svn-src-head@freebsd.org Content-Type: text/plain; charset="UTF-8" X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 31 Jan 2018 17:08:16 -0000 On 31 January 2018 at 09:56, Bjoern A. Zeeb wrote: > 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 had a similar thought while the change was in review, but saw that a number of tunables in similar areas also have negative sense. That said perhaps (some minor) consistency is not enough of an argument for the somewhat more confusing sense.