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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 C16D9C3F2CD for ; Wed, 4 Mar 2020 12:17:13 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 9134C20848 for ; Wed, 4 Mar 2020 12:17:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9134C20848 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 fraxinus.osuosl.org (Postfix) with ESMTP id 6104E84F2E; Wed, 4 Mar 2020 12:17:13 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UPCtClzb1rn7; Wed, 4 Mar 2020 12:17:11 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id E995584E77; Wed, 4 Mar 2020 12:17:11 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id CEBF3C089F; Wed, 4 Mar 2020 12:17:11 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id BE981C013E for ; Wed, 4 Mar 2020 12:17:10 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id ABDEB8622A for ; Wed, 4 Mar 2020 12:17:10 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id PrhD+JwOEoIB for ; Wed, 4 Mar 2020 12:17:10 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by whitealder.osuosl.org (Postfix) with ESMTPS id B496486230 for ; Wed, 4 Mar 2020 12:17:09 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Mar 2020 04:17:09 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,514,1574150400"; d="scan'208";a="413131884" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.211.93]) ([10.254.211.93]) by orsmga005.jf.intel.com with ESMTP; 04 Mar 2020 04:17:05 -0800 Subject: Re: [PATCH V2 3/5] iommu: Add support to change default domain of an iommu_group To: Joerg Roedel References: <5aa5ef20ff81f706aafa9a6af68cef98fe60ad0f.1581619464.git.sai.praneeth.prakhya@intel.com> <20200302150833.GA6540@8bytes.org> <7fcadd2a-76cd-2114-bb5f-c916fd14e1cb@linux.intel.com> <20200303131326.GB13185@8bytes.org> From: Lu Baolu Message-ID: <64f24e39-2abb-992d-d7ca-8e47c927aff3@linux.intel.com> Date: Wed, 4 Mar 2020 20:17:04 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200303131326.GB13185@8bytes.org> Content-Language: en-US Cc: Ashok Raj , Will Deacon , iommu@lists.linux-foundation.org, Robin Murphy , 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" Hi Joerg, On 2020/3/3 21:13, Joerg Roedel wrote: > Hi Baolu, > > On Tue, Mar 03, 2020 at 02:47:02PM +0800, Lu Baolu wrote: >> Theoretically speaking, per-device default domain is impractical. PCI >> aliased devices (PCI bridge and all devices beneath it, VMD devices and >> various devices quirked with pci_add_dma_alias()) must use the same >> domain. It's likely that we have to introduce something like a sub-group >> with all PCI aliased devices staying in it. Current private-domain >> implementation in the vt-d driver was introduced for compatible purpose >> and I wanted to abandon it from the first day. :-) > > What hinders you from removing it now? I looked a bit closer into > these private default domain implementation and it is very fragile. If > it can be removed, then better do so sooner than later. > I will soon send out the patches for review. >> Probably, we are able to configure per-group default domain type with >> below two interfaces. >> >> - (ops->)dev_def_domain_type: Return the required default domain type >> for a device. It returns >> - IOMMU_DOMAIN_DMA (device must use a DMA domain), unlikely >> - IOMMU_DOMAIN_IDENTITY (device must use an Identity domain), unlikely >> - 0 (both are okay), likely > > If we stay at the group level, this interface should work on the group > level too, and not on the device level. > >> - iommu_group_change_def_domain: Change the default domain of a group >> Works only when all devices have no driver bond. > > Btw, I have no objections about the concept of private default domains > for devices, but the implementation should be moved to generic IOMMU > code so that the behavior is consistent accross differnet IOMMU > platforms, and of course be robust. > Yes. I agree with you. > > Regards, > > Joerg > Best regards, baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu