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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 C1FCAC5519F for ; Thu, 19 Nov 2020 02:43:32 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 2FDFE246BB for ; Thu, 19 Nov 2020 02:43:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2FDFE246BB 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 hemlock.osuosl.org (Postfix) with ESMTP id C3CD9872F8; Thu, 19 Nov 2020 02:43:31 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dJkYzqM78X0I; Thu, 19 Nov 2020 02:43:30 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id DF422872F2; Thu, 19 Nov 2020 02:43:30 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id C3CD7C0891; Thu, 19 Nov 2020 02:43:30 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 0FD79C07FF for ; Thu, 19 Nov 2020 02:43:30 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id E1B3822F05 for ; Thu, 19 Nov 2020 02:43:29 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id lbnW5crgi-Ca for ; Thu, 19 Nov 2020 02:43:26 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by silver.osuosl.org (Postfix) with ESMTPS id B114E22E89 for ; Thu, 19 Nov 2020 02:43:26 +0000 (UTC) IronPort-SDR: VYp+9rmtL3tfuSLkSwMEtE1hgRyBSQlIyb9qr5smUHwwo42NLMwVoiJMcVtOnDhYyNFipEcU12 WXWHDT97i+wA== X-IronPort-AV: E=McAfee;i="6000,8403,9809"; a="158255258" X-IronPort-AV: E=Sophos;i="5.77,489,1596524400"; d="scan'208";a="158255258" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2020 18:43:25 -0800 IronPort-SDR: iJ81quWRVvsyANxvNY2O3Hhj+SZY+YnCbCMs5+n3L4yZSHQCt1dRCUnJOFhwY3QcwSaROosWGe 5Xpb/P93mpuw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,489,1596524400"; d="scan'208";a="431085375" Received: from allen-box.sh.intel.com (HELO [10.239.159.28]) ([10.239.159.28]) by fmsmga001.fm.intel.com with ESMTP; 18 Nov 2020 18:43:24 -0800 Subject: Re: [Patch V8 0/3] iommu: Add support to change default domain of an iommu group To: Will Deacon , Ashok Raj , robin.murphy@arm.com References: <20200925190620.18732-1-ashok.raj@intel.com> <20201118135225.GC2177@willie-the-truck> From: Lu Baolu Message-ID: Date: Thu, 19 Nov 2020 10:36:15 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201118135225.GC2177@willie-the-truck> Content-Language: en-US Cc: iommu@lists.linux-foundation.org, Will Deacon , Christoph Hellwig 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 11/18/20 9:52 PM, Will Deacon wrote: > On Fri, Sep 25, 2020 at 12:06:17PM -0700, Ashok Raj wrote: >> Presently, the default domain of an iommu group is allocated during boot time >> and it cannot be changed later. So, the device would typically be either in >> identity (pass_through) mode or the device would be in DMA mode as long as the >> system is up and running. There is no way to change the default domain type >> dynamically i.e. after booting, a device cannot switch between identity mode and >> DMA mode. >> >> Assume a use case wherein the privileged user would want to use the device in >> pass-through mode when the device is used for host so that it would be high >> performing. Presently, this is not supported. Hence add support to change the >> default domain of an iommu group dynamically. >> >> Support this by writing to a sysfs file, namely >> "/sys/kernel/iommu_groups//type". >> >> Testing: >> -------- >> Tested by dynamically changing storage device (nvme) from >> 1. identity mode to DMA and making sure file transfer works >> 2. DMA mode to identity mode and making sure file transfer works >> Tested only for intel_iommu/vt-d. Would appreciate if someone could test on AMD >> and ARM based machines. >> >> Based on iommu maintainer's 'next' branch. > > Modulo my minor comments, I think this looks good for 5.11 if you can > please send a version 9. > > Robin -- please can you give it the once-over too? I think root can break > things quite badly with this interface, but root can do that in other ways > anyway... Sure. I will send a v9 after Robin's review. > > Will Best regards, baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu