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=-0.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_MUTT 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 E46DAC04E87 for ; Thu, 16 May 2019 08:16:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B6BDB206A3 for ; Thu, 16 May 2019 08:16:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557994593; bh=PdCpmUbmpqpTdBKFLPFgjQgpSknHTPpWqz0nse0/6GA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=hfoHLS4v9PvnawhOY+0PpAcUqP4hht4nDvVd2WZRlJuXc+4iW3qUmqZvCybrRAEZH qE4/qAFDMZOdWnkkpyOU/qLjLmp5cO0aOToiYP1sw9/anWXFoTuR1rmkD+ACdNGCDz CSZnmlg8BW7pUN560PdudckQjYi6dBUh3uGzCpfE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726739AbfEPIQc (ORCPT ); Thu, 16 May 2019 04:16:32 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:45223 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726272AbfEPIQc (ORCPT ); Thu, 16 May 2019 04:16:32 -0400 Received: by mail-wr1-f67.google.com with SMTP id b18so2233123wrq.12; Thu, 16 May 2019 01:16:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=0fnfe8Q9cs3mUyaf6ypStYy6Jn39oq2+1juaIcTgyT8=; b=qPMurDwKMikN+99yRkycl0UBlF9+bsgsK+t/KBSNF8dv9njkGn+bh2cyDWKlBylvhS nrWkZN3AKrr55HSxYWe5KBWlgve2PUg5PqqPyO8xS2zzkT5VmLjvTNqmeygfcb5sl91h mgBBlfBPtcZl3Y62KgjR8eBflUdFMjQZscpHF3A/TGuKGFWoCJqum4nWCrVigh/K03u+ hICm2254MRLzISmjKns22x9SW1zP7o7VxGOfMu+wCr9MnJRGx8B4z9N+H6fKIoO8Dsvy Cz9LjM/6XATDqdmm/wU/4PUmmzxB5T0W1wUiM84beF2/0dUDKTeY2JUW1kkgpt8KoYIl CYgw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=0fnfe8Q9cs3mUyaf6ypStYy6Jn39oq2+1juaIcTgyT8=; b=tkEWMuPksBrTgcu0qIA3Zq3AWagYn8IXd8Umi9ckPTnyaz73HDOtJqfuRtV02APmNu LKnNLWHMuTbx0s7UBKDFwNmHzRiNkT/npqTMjHPhlObbe6J9HzohIP5HJwW78dfk6hEt QDty8GnoRIy5K2YVGieygVIWCc7QpNBLpOK3DFi+U5qTiBgM6BqSyXqb3ds0uROeoKRY C8UwARmGn4susKkMIAQSZcUfjW+IyIHi5og+4VMOqietu4e8BtY5MnlbxEd4O4p/1kvT MCLdFIcRvSuTsXemINzUpUvNLKfLhmV+YQYPRiZcb80z+1EmSaMj+3NI6LDiIFb7iSfb RTIQ== X-Gm-Message-State: APjAAAXlhpYywPjKquxPqOX2pWcY3qvUMgcDtUBDBm75qsgXaA3wHkym vkhBrTTq6ep4W+CBTTram74= X-Google-Smtp-Source: APXvYqxjSfJRXAtTYKgQve1Gfd36DHEOs3ixCCYsa6uTbx/h4372ohZLd7H2PLAYHboVJJ5dTV5H9Q== X-Received: by 2002:adf:afdf:: with SMTP id y31mr26761723wrd.315.1557994590605; Thu, 16 May 2019 01:16:30 -0700 (PDT) Received: from gmail.com (2E8B0CD5.catv.pool.telekom.hu. [46.139.12.213]) by smtp.gmail.com with ESMTPSA id d3sm6175861wmf.46.2019.05.16.01.16.29 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 16 May 2019 01:16:29 -0700 (PDT) Date: Thu, 16 May 2019 10:16:27 +0200 From: Ingo Molnar To: Jiri Kosina Cc: Geert Uytterhoeven , Josh Poimboeuf , Thomas Gleixner , Peter Zijlstra , Greg Kroah-Hartman , Ben Hutchings , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] cpu/speculation: Warn on unsupported mitigations= parameter Message-ID: <20190516081627.GA109450@gmail.com> References: <20190516070935.22546-1-geert@linux-m68k.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 * Jiri Kosina wrote: > On Thu, 16 May 2019, Geert Uytterhoeven wrote: > > > Currently, if the user specifies an unsupported mitigation strategy on > > the kernel command line, it will be ignored silently. The code will > > fall back to the default strategy, possibly leaving the system more > > vulnerable than expected. > > Honestly, I am not convinced. We are not doing this for vast majority of > other cmdline options either, if for any at all. That's really a weakness - I've been bitten by this previously: I typoed or mis-remembered a command line option and didn't have it while I thought I had it. Our boot-commandline library is pretty user-unfriendly. Thanks, Ingo