From owner-svn-src-head@freebsd.org Wed Jan 31 21:06:11 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 4ECE4EE1C5C for ; Wed, 31 Jan 2018 21:06:11 +0000 (UTC) (envelope-from steven@multiplay.co.uk) Received: from mail-yw0-x22f.google.com (mail-yw0-x22f.google.com [IPv6:2607:f8b0:4002:c05::22f]) (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 DBDA4784D4 for ; Wed, 31 Jan 2018 21:06:10 +0000 (UTC) (envelope-from steven@multiplay.co.uk) Received: by mail-yw0-x22f.google.com with SMTP id t201so8692178ywf.1 for ; Wed, 31 Jan 2018 13:06:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=multiplay-co-uk.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=JSkF7wqyD/+2RUkG1MIDYsuDGCwG+h/C4IJ7pd9jKkU=; b=PMeaF2oiQXdG1X2W6NNC1TH1g21/NClpPCVZ6B0gNlhusbicKe0Oazu4aMaqbUQ1AA 2wss4GVRKdbLWm7GVs0HS9ho6EEf9KcPgViosW6bAxQwfNf7jMbAP+QRH5jJboyf9c2P 4caRbKLfb9c3ntnx7oxJ18BX+SQkkoSz63qFf4D6nuw7vGxjr99LFSIErZL9Ixw4dHPJ aMDwtk3vgGOhTZVNawZ+zuo8rs160O+YatVtF0MVNtU8LYZan4VmVDl/03NAfIKc5b4u wUrznLY+bOMqz1J4GX37s7bryt12sFkfHawJ+32aD5vBwheV1qeQCESQMPM667ojxYUb oGaQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=JSkF7wqyD/+2RUkG1MIDYsuDGCwG+h/C4IJ7pd9jKkU=; b=Pzyt4ZbdeAnEpsLRmrVyhC/Hd6ckLwKNNQBvX8g8txkDkMBqe4OobNcRXdbjRjULRx UFA/N41n0olPA7TX8DVnZ58kAqHhiPuskQukjt7U6oZXVzaHxyMKH02OI3E0bnsXnoLb 1264QTxPvnV33iiCJlGC3AFfuB9B+h1OZNwXvpYsnVha65o5cpdlNjheIj3ipSHrhbm5 wW3S6HeqBJYr3mdqdzzRuZvLkBXXnid86Toc+HX9mfGrXsFeMVRwARYNHh+Coq08x1PV l5/PQVAF4RU/QNaCLtDv9HxxQ4D1D6+ltSSA2g0DUPET7jPBrebc1ZAU4J8FFmcMjJmj nnnw== X-Gm-Message-State: AKwxytfRqSY8QasNqpnSAygtFTi5is34CgGLbjlmwlyRWgEuUKopFn1Z Vqgi9HhamPLWXVotpdRbRyFNl/Ty9tuO73lTgVylgbWV X-Google-Smtp-Source: AH8x224kE1Mbpzji1htvvdKn0L4KGJQS8BssDu7Pv7oov/NXg9nP636vyarxyv4SVncdiN6cSq9Kn4BHJ0froQMqVtw= X-Received: by 10.129.10.215 with SMTP id 206mr22905078ywk.117.1517432769981; Wed, 31 Jan 2018 13:06:09 -0800 (PST) MIME-Version: 1.0 References: <20180131164455.GR97752@kib.kiev.ua> <201801311805.w0VI5DsU031265@pdx.rh.CN85.dnsmgr.net> In-Reply-To: <201801311805.w0VI5DsU031265@pdx.rh.CN85.dnsmgr.net> From: Steven Hartland Date: Wed, 31 Jan 2018 21:05:58 +0000 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: rgrimes@freebsd.org Cc: "Bjoern A. Zeeb" , Konstantin Belousov , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.25 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 21:06:11 -0000 Pretty sure I=E2=80=99ve seen that too On Wed, 31 Jan 2018 at 18:05, Rodney W. Grimes < freebsd@pdx.rh.cn85.dnsmgr.net> wrote: > > On Wed, Jan 31, 2018 at 02:56:24PM +0000, 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 th= e > > > default setting along). > > This is done consistently with the hw.clflush_disable. > > Anyway, the intent is that the knob will be used for disabling, > > since defaults are going to be changed in the near future. > > I thought we had something some place that said negative assertions > should be avoided if possible. > > > > 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 Branc= h > > > Restricted Speculation (IBRS)???? > > Will do in half a hour. > > > -- > Rod Grimes > rgrimes@freebsd.org > >