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=-5.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 DB67DC47096 for ; Thu, 3 Jun 2021 18:01:11 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (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 79D48613E3 for ; Thu, 3 Jun 2021 18:01:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 79D48613E3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 37E4984165; Thu, 3 Jun 2021 18:01:11 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id bvqqKO0dfhYG; Thu, 3 Jun 2021 18:01:09 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTP id 6627584136; Thu, 3 Jun 2021 18:01:08 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 3DD31C000E; Thu, 3 Jun 2021 18:01:08 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 08A77C0001; Thu, 3 Jun 2021 18:01:07 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id D376D40611; Thu, 3 Jun 2021 18:01:06 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 53V_6drYf6yN; Thu, 3 Jun 2021 18:01:00 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by smtp4.osuosl.org (Postfix) with ESMTPS id D7B7C4060C; Thu, 3 Jun 2021 18:00:59 +0000 (UTC) IronPort-SDR: 9u7lB+de0ppGOwkkSjC2LR9ZHxjWZ9YveL1LwmAMMDKUQSWhxJjFjUUW9O07Km4/gTA6tWJsw3 W1e4IKMOibew== X-IronPort-AV: E=McAfee;i="6200,9189,10004"; a="267969980" X-IronPort-AV: E=Sophos;i="5.83,246,1616482800"; d="scan'208";a="267969980" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jun 2021 11:00:51 -0700 IronPort-SDR: zWl9IAVAqjS/nU7br8N4D0lZd7U38PTrXKOJDam1wiKAadNjauAH+/i6mcx4J0u5MOYtULc7BU orc5GUV+Jo2Q== X-IronPort-AV: E=Sophos;i="5.83,246,1616482800"; d="scan'208";a="550787338" Received: from akleen-mobl1.amr.corp.intel.com (HELO [10.209.7.237]) ([10.209.7.237]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jun 2021 11:00:48 -0700 Subject: Re: [PATCH v1 1/8] virtio: Force only split mode with protected guest To: Andy Lutomirski , mst@redhat.com References: <20210603004133.4079390-1-ak@linux.intel.com> <20210603004133.4079390-2-ak@linux.intel.com> From: Andi Kleen Message-ID: Date: Thu, 3 Jun 2021 11:00:47 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Cc: jasowang@redhat.com, x86@kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, iommu@lists.linux-foundation.org, jpoimboe@redhat.com, robin.murphy@arm.com, hch@lst.de X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 6/3/2021 10:33 AM, Andy Lutomirski wrote: > On 6/2/21 5:41 PM, Andi Kleen wrote: >> Only allow split mode when in a protected guest. Followon >> patches harden the split mode code paths, and we don't want >> an malicious host to force anything else. Also disallow >> indirect mode for similar reasons. > I read this as "the virtio driver is buggy. Let's disable most of the > buggy code in one special case in which we need a driver without bugs. > In all the other cases (e.g. hardware virtio device connected over > USB-C), driver bugs are still allowed." My understanding is most of the other modes (except for split with separate descriptors) are obsolete and just there for compatibility. As long as they're deprecated they won't harm anyone. -Andi _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu