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=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 60929C10F0A for ; Fri, 5 Apr 2019 16:07:21 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D9BD7204EC for ; Fri, 5 Apr 2019 16:07:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D9BD7204EC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 44bPpZ5Z7pzDqVm for ; Sat, 6 Apr 2019 03:07:18 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=redhat.com (client-ip=209.132.183.28; helo=mx1.redhat.com; envelope-from=jpoimboe@redhat.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=redhat.com Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 44bPmn6fVtzDqSV for ; Sat, 6 Apr 2019 03:05:45 +1100 (AEDT) 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 D639544FA7; Fri, 5 Apr 2019 16:05:43 +0000 (UTC) Received: from treble (ovpn-123-87.rdu2.redhat.com [10.10.123.87]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C756660C8D; Fri, 5 Apr 2019 16:05:38 +0000 (UTC) Date: Fri, 5 Apr 2019 11:05:36 -0500 From: Josh Poimboeuf To: Borislav Petkov Subject: Re: [PATCH RFC 2/5] x86/speculation: Add support for 'cpu_spec_mitigations=' cmdline options Message-ID: <20190405160536.sks2hmo6sxnxg3tl@treble> References: <78c63cb08f36f55407f534d49cc2543079e44dbb.1554396090.git.jpoimboe@redhat.com> <20190405135712.GF23348@zn.tnic> <20190405143101.ksj7ayjis4p52dgt@treble> <20190405152650.GH23348@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190405152650.GH23348@zn.tnic> 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 [10.5.110.30]); Fri, 05 Apr 2019 16:05:44 +0000 (UTC) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , Heiko Carstens , Paul Mackerras , "H . Peter Anvin" , Ingo Molnar , Andrea Arcangeli , linux-s390@vger.kernel.org, x86@kernel.org, Will Deacon , Linus Torvalds , Catalin Marinas , Waiman Long , linux-arch@vger.kernel.org, Jon Masters , Jiri Kosina , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Tyler Hicks , Martin Schwidefsky , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Apr 05, 2019 at 05:26:50PM +0200, Borislav Petkov wrote: > On Fri, Apr 05, 2019 at 09:31:01AM -0500, Josh Poimboeuf wrote: > > My thinking was that the individual options could be used to override > > the global option. But maybe that's overkill? I dunno. > > You mean if the user deliberately types: > > "cpu_spec_mitigations=off spectre_v2=auto" > > on the cmdline to turn off all and then enable only one? > > Hmm, yap, sounds like an overkill to me. Then I'd probably do: > > pr_err("Make up your mind already!\n"); > return; > > :-)) > > I'd say let's do the simpler and cleaner thing now and think about > supporting this overkill when it really turns out that it is needed. Fair enough. > > I assume you mean just the part where L1TF_MITIGATION_DEFAULT is added? > > Yap. Ok. -- Josh