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,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 8AE9CC433ED for ; Thu, 15 Apr 2021 05:43:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 663EF613EA for ; Thu, 15 Apr 2021 05:43:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230136AbhDOFnb (ORCPT ); Thu, 15 Apr 2021 01:43:31 -0400 Received: from mga01.intel.com ([192.55.52.88]:42578 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229731AbhDOFn2 (ORCPT ); Thu, 15 Apr 2021 01:43:28 -0400 IronPort-SDR: USESvSCLFKEurnpcSUNwMEDJsQWqPHkinuYOj3CKDSxi5zt/1t5oYScleiXoCAsRb1LIqi7kVP aVcEfH20kkwQ== X-IronPort-AV: E=McAfee;i="6200,9189,9954"; a="215293714" X-IronPort-AV: E=Sophos;i="5.82,223,1613462400"; d="scan'208";a="215293714" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2021 22:43:05 -0700 IronPort-SDR: qEktfdrmGT45qn1aebxUB/pJx/fKbBwcm0+niphEjWBJrJDcuLrO5f66T2wQ+beTfa0wFwnYSB 426qxLrFMI5w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.82,223,1613462400"; d="scan'208";a="444065380" Received: from allen-box.sh.intel.com (HELO [10.239.159.128]) ([10.239.159.128]) by fmsmga004.fm.intel.com with ESMTP; 14 Apr 2021 22:43:02 -0700 Cc: baolu.lu@linux.intel.com, Jacob Pan , Jean-Philippe Brucker , LKML , iommu@lists.linux-foundation.org, Joerg Roedel , Jean-Philippe Brucker , Yi Liu , Raj Ashok , "Tian, Kevin" , Dave Jiang , wangzhou1@hisilicon.com, zhangfei.gao@linaro.org, vkoul@kernel.org Subject: Re: [PATCH 2/2] iommu/sva: Remove mm parameter from SVA bind API To: Jason Gunthorpe References: <1617901736-24788-1-git-send-email-jacob.jun.pan@linux.intel.com> <1617901736-24788-2-git-send-email-jacob.jun.pan@linux.intel.com> <20210409110305.6b0471d9@jacob-builder> <20210413170947.35ba9267@jacob-builder> <41433d99-e413-f5bf-5279-695dae6c58ba@linux.intel.com> <20210414112602.GA1370958@nvidia.com> From: Lu Baolu Message-ID: Date: Thu, 15 Apr 2021 13:33:24 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210414112602.GA1370958@nvidia.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jason, On 4/14/21 7:26 PM, Jason Gunthorpe wrote: > On Wed, Apr 14, 2021 at 02:22:09PM +0800, Lu Baolu wrote: > >> I still worry about supervisor pasid allocation. >> >> If we use iommu_sva_alloc_pasid() to allocate a supervisor pasid, which >> mm should the pasid be set? I've ever thought about passing &init_mm to >> iommu_sva_alloc_pasid(). But if you add "mm != current->mm", this seems >> not to work. Or do you prefer a separated interface for supervisor pasid >> allocation/free? > > Without a mm_struct it is not SVA, so don't use SVA APIs for whatever > a 'supervisor pasid' is The supervisor PASID has its mm_struct. The only difference is that the device will set priv=1 in its DMA transactions with the PASID. Best regards, baolu