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=-2.9 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_NEOMUTT autolearn=ham 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 5631AC4646D for ; Wed, 8 Aug 2018 09:14:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 095F721708 for ; Wed, 8 Aug 2018 09:14:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=8bytes.org header.i=@8bytes.org header.b="hrLQOm+E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 095F721708 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=8bytes.org 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 S1727461AbeHHLco (ORCPT ); Wed, 8 Aug 2018 07:32:44 -0400 Received: from 8bytes.org ([81.169.241.247]:60904 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727174AbeHHLco (ORCPT ); Wed, 8 Aug 2018 07:32:44 -0400 Received: by theia.8bytes.org (Postfix, from userid 1000) id 7DD682EA; Wed, 8 Aug 2018 11:13:55 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=8bytes.org; s=mail-1; t=1533719635; bh=7ZFcRR7M/mZfzjWZIjVz2jVZ4Dq5tB4gZ5scTn5OMTA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hrLQOm+Emje7OPRGWYoa/jpYQpeVIoBnp/5IenG0tijkT6OnD5BtGA1FHi4XcSlLT wqnDQuGR4WDjty70l7VG7HxWM3lrX2aF8yiq1Dys6YGuPGq08TYzh7cUtfw5QfPboe 5rBkCxengu856MfA6w3DQXrb7LcbcOwfYtWOpIUrc11VzhWF65go1D/u9g9/0suxiJ H/Z27AiRp1eiqLy6ZPHkZVU0PA5tw7exNQOQSt+a0grRlImM2A0fmrqfkBXMXOY0KA fybGlfU3nA78knd+VyElfM6ct/LrZMWmIXfNIbh+EPisO+BU9q6pxK7cVJ3rSzb1Oo 83T4ciRLUS26w== Date: Wed, 8 Aug 2018 11:13:54 +0200 From: Joerg Roedel To: Kenneth Lee Cc: Jonathan Corbet , Herbert Xu , "David S . Miller" , Alex Williamson , Kenneth Lee , Hao Fang , Zhou Wang , Zaibo Xu , Philippe Ombredanne , Greg Kroah-Hartman , Thomas Gleixner , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, iommu@lists.linux-foundation.org, kvm@vger.kernel.org, linux-accelerators@lists.ozlabs.org, Lu Baolu , Sanjay Kumar , linuxarm@huawei.com Subject: Re: [RFC PATCH 2/7] iommu: Add share domain interface in iommu for spimdev Message-ID: <20180808091354.ppqgineql3pufwwr@8bytes.org> References: <20180801102221.5308-1-nek.in.cn@gmail.com> <20180801102221.5308-3-nek.in.cn@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180801102221.5308-3-nek.in.cn@gmail.com> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 01, 2018 at 06:22:16PM +0800, Kenneth Lee wrote: > From: Kenneth Lee > > This patch add sharing interface for a iommu_group. The new interface: > > iommu_group_share_domain() > iommu_group_unshare_domain() > > can be used by some virtual iommu_group (such as iommu_group for spimdev) > to share their parent's iommu_group. > > When the domain of the group is shared, it cannot be changed before > unshared. In the future, notification can be added if update is required. >From the description or the patch I don't really get why this is needed. Please update the description and make a case for this API addition. Joerg