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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 61CD2C433B4 for ; Thu, 22 Apr 2021 12:56:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 262AA61417 for ; Thu, 22 Apr 2021 12:56:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236334AbhDVM47 (ORCPT ); Thu, 22 Apr 2021 08:56:59 -0400 Received: from mga11.intel.com ([192.55.52.93]:50634 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236250AbhDVM44 (ORCPT ); Thu, 22 Apr 2021 08:56:56 -0400 IronPort-SDR: MumVY8dUwPgqFynXsxHqJV2GsvhLeiWdsT5HsLkuFHwWOf29j28O++mg654Wa3EcWJ0oNNmwak f3LRXZQVmp+Q== X-IronPort-AV: E=McAfee;i="6200,9189,9961"; a="192692233" X-IronPort-AV: E=Sophos;i="5.82,242,1613462400"; d="scan'208";a="192692233" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Apr 2021 05:56:21 -0700 IronPort-SDR: y1fbkouyq0pnuB+LErciUqaGFcqjHgtZrsWF26wfwvrJ3dQFNFuVxqLxJfuF3qhXa4XEqx3Vrr nxcKimXuEhSg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.82,242,1613462400"; d="scan'208";a="446262806" Received: from yiliu-dev.bj.intel.com (HELO yiliu-dev) ([10.238.156.135]) by fmsmga004.fm.intel.com with ESMTP; 22 Apr 2021 05:56:17 -0700 Date: Thu, 22 Apr 2021 20:55:05 +0800 From: Liu Yi L To: Alex Williamson Cc: yi.l.liu@intel.com, Jason Gunthorpe , Jean-Philippe Brucker , "Tian, Kevin" , "Jiang, Dave" , "Raj, Ashok" , Jonathan Corbet , Jean-Philippe Brucker , Li Zefan , LKML , "iommu@lists.linux-foundation.org" , Johannes Weiner , Tejun Heo , "cgroups@vger.kernel.org" , "Wu, Hao" , David Woodhouse Subject: Re: [PATCH V4 05/18] iommu/ioasid: Redefine IOASID set and allocation APIs Message-ID: <20210422205505.75f086f8@yiliu-dev> In-Reply-To: <20210421133312.15307c44@redhat.com> References: <20210401134236.GF1463678@nvidia.com> <20210401160337.GJ1463678@nvidia.com> <4bea6eb9-08ad-4b6b-1e0f-c97ece58a078@redhat.com> <20210415230732.GG1370958@nvidia.com> <20210416061258.325e762e@jacob-builder> <20210416094547.1774e1a3@redhat.com> <20210421162307.GM1370958@nvidia.com> <20210421105451.56d3670a@redhat.com> <20210421175203.GN1370958@nvidia.com> <20210421133312.15307c44@redhat.com> Organization: IAGS/SSE(OTC) X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 21 Apr 2021 13:33:12 -0600, Alex Williamson wrote: > On Wed, 21 Apr 2021 14:52:03 -0300 > Jason Gunthorpe wrote: > > > On Wed, Apr 21, 2021 at 10:54:51AM -0600, Alex Williamson wrote: > > > > > That's essentially replacing vfio-core, where I think we're more > > > > I am only talking about /dev/vfio here which is basically the IOMMU > > interface part. > > > > I still expect that VFIO_GROUP_SET_CONTAINER will be used to connect > > /dev/{ioasid,vfio} to the VFIO group and all the group and device > > logic stays inside VFIO. > > But that group and device logic is also tied to the container, where > the IOMMU backend is the interchangeable thing that provides the IOMMU > manipulation for that container. If you're using > VFIO_GROUP_SET_CONTAINER to associate a group to a /dev/ioasid, then > you're really either taking that group outside of vfio or you're > re-implementing group management in /dev/ioasid. I'd expect the > transition point at VFIO_SET_IOMMU. per my understanding, transiting at the VFIO_SET_IOMMU point makes more sense as VFIO can still have the group and device logic, which is the key concept of group granularity isolation for userspace direct access. -- Regards, Yi Liu