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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 D700AC4360F for ; Fri, 5 Apr 2019 15:26:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8B682184B for ; Fri, 5 Apr 2019 15:26:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="kPnz31QV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731362AbfDEP0z (ORCPT ); Fri, 5 Apr 2019 11:26:55 -0400 Received: from mail.skyhub.de ([5.9.137.197]:57100 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726291AbfDEP0z (ORCPT ); Fri, 5 Apr 2019 11:26:55 -0400 Received: from zn.tnic (p200300EC2F148A00329C23FFFEA6A903.dip0.t-ipconnect.de [IPv6:2003:ec:2f14:8a00:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id E9B8D1EC037C; Fri, 5 Apr 2019 17:26:52 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1554478013; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=O0cTCgEX36c/m5EFCMWGNXRJyyFq2WbwhodTsWiALgI=; b=kPnz31QV8uhWtABEfU/bzWN08N6g06VYZQKpLw/d60BAas9iufZP6+ugGuHLDNatjI+Bxk O01LlJ/jGQp0X14n6OZiEPvLxxZbpo7/16SEDIpNKgXFq4wRRaLUH38BbzWuzSLKjTJpEG EmWaFNLgoHbV8753hjlVcLKkmLlALqo= Date: Fri, 5 Apr 2019 17:26:50 +0200 From: Borislav Petkov To: Josh Poimboeuf Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Jiri Kosina , Waiman Long , Andrea Arcangeli , Jon Masters , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , 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 2/5] x86/speculation: Add support for 'cpu_spec_mitigations=' cmdline options Message-ID: <20190405152650.GH23348@zn.tnic> References: <78c63cb08f36f55407f534d49cc2543079e44dbb.1554396090.git.jpoimboe@redhat.com> <20190405135712.GF23348@zn.tnic> <20190405143101.ksj7ayjis4p52dgt@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190405143101.ksj7ayjis4p52dgt@treble> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > I assume you mean just the part where L1TF_MITIGATION_DEFAULT is added? Yap. Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.