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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 D5750C04EBF for ; Thu, 15 Nov 2018 19:32:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9831E21582 for ; Thu, 15 Nov 2018 19:32:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9831E21582 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729058AbeKPFlO (ORCPT ); Fri, 16 Nov 2018 00:41:14 -0500 Received: from mga11.intel.com ([192.55.52.93]:5289 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725742AbeKPFlO (ORCPT ); Fri, 16 Nov 2018 00:41:14 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Nov 2018 11:32:07 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,237,1539673200"; d="scan'208";a="92381520" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.157]) by orsmga008.jf.intel.com with SMTP; 15 Nov 2018 11:32:01 -0800 Received: by lahna (sSMTP sendmail emulation); Thu, 15 Nov 2018 21:32:01 +0200 Date: Thu, 15 Nov 2018 21:32:01 +0200 From: Mika Westerberg To: Lukas Wunner Cc: Yehezkel Bernat , lorenzo.pieralisi@arm.com, iommu@lists.linux-foundation.org, joro@8bytes.org, David Woodhouse , baolu.lu@linux.intel.com, ashok.raj@intel.com, Bjorn Helgaas , rjw@rjwysocki.net, jacob.jun.pan@intel.com, Andreas Noever , michael.jamet@intel.com, Christian Kellner , Mario Limonciello , Anthony Wong , linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, LKML Subject: Re: [PATCH 1/4] PCI / ACPI: Identify external PCI devices Message-ID: <20181115193201.GF4179@lahna.fi.intel.com> References: <20181113114527.GA12821@e107981-ln.cambridge.arm.com> <20181115102239.GU2500@lahna.fi.intel.com> <20181115111356.GA599@e107981-ln.cambridge.arm.com> <20181115113737.GW2500@lahna.fi.intel.com> <20181115120736.pscly6zwd3k2tvd2@wunner.de> <20181115121627.GA2500@lahna.fi.intel.com> <20181115174608.GA17691@e107981-ln.cambridge.arm.com> <20181115191026.GE4179@lahna.fi.intel.com> <20181115192741.4ugt6usmsemokxle@wunner.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181115192741.4ugt6usmsemokxle@wunner.de> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo 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 Thu, Nov 15, 2018 at 08:27:41PM +0100, Lukas Wunner wrote: > On Thu, Nov 15, 2018 at 09:10:26PM +0200, Mika Westerberg wrote: > > I was thinking we could cover all these with is_external filling them > > based on the _DSD or some other means in the kernel. > > > > We would then deal all such devices as "untrusted" by default. > > Tinfoil hat on, even internal devices could be malicious. > What's the downside of enabling the feature for everything? Mostly performance, I think. That's the main reason we put all non external devices to passthrough IOMMU mode.