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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham 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 18374C10F13 for ; Thu, 11 Apr 2019 13:15:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E55492077C for ; Thu, 11 Apr 2019 13:15:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726682AbfDKNPs (ORCPT ); Thu, 11 Apr 2019 09:15:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51868 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726145AbfDKNPs (ORCPT ); Thu, 11 Apr 2019 09:15:48 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B4BDE30832DE; Thu, 11 Apr 2019 13:15:47 +0000 (UTC) Received: from treble (ovpn-120-231.rdu2.redhat.com [10.10.120.231]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3AA9061998; Thu, 11 Apr 2019 13:15:42 +0000 (UTC) Date: Thu, 11 Apr 2019 08:15:40 -0500 From: Josh Poimboeuf To: Thomas Gleixner Cc: Michael Ellerman , Borislav Petkov , linux-kernel@vger.kernel.org, x86@kernel.org, Ingo Molnar , "H . Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Jiri Kosina , Waiman Long , Andrea Arcangeli , Jon Masters , Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, Martin Schwidefsky , Heiko Carstens , linux-s390@vger.kernel.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, Greg Kroah-Hartman , Tyler Hicks , Linus Torvalds Subject: Re: [PATCH RFC 1/5] cpu/speculation: Add 'cpu_spec_mitigations=' cmdline options Message-ID: <20190411131540.754t5t4tp55i6vjq@treble> References: <20190405131211.GE23348@zn.tnic> <20190405142048.burthk2jnpcvi2om@treble> <20190405152059.GG23348@zn.tnic> <20190405160136.GI23348@zn.tnic> <20190405161852.nmpk22omgiety4df@treble> <87sguqwgu7.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Thu, 11 Apr 2019 13:15:48 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 10, 2019 at 02:10:01PM +0200, Thomas Gleixner wrote: > On Wed, 10 Apr 2019, Michael Ellerman wrote: > > Josh Poimboeuf writes: > > > > > On Fri, Apr 05, 2019 at 06:01:36PM +0200, Borislav Petkov wrote: > > >> Thinking about this more, we can shave off the first 4 chars and have it > > >> be: > > >> > > >> spec_mitigations= > > >> > > >> I think it is painfully clear which speculation mitigations we mean. And > > >> the other switches don't have "cpu_" prefixes too so... > > > > > > Sure, I'm ok with renaming it to that, if there are no objections. > > > > What about when we have a mitigation for a non-speculation related bug :) > > Those kind of silicon bugs are usually mitigated unconditionally. Right. But at least "mitigations=" is nice and short. We could clarify in the documentation that it doesn't apply to *all* mitigations, only the ones which are optional and which can affect performance. And it would give us the freedom to include any future "optional" mitigations, spec or not. I kind of like it. But I could go either way. -- Josh