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 E247FC41620 for ; Thu, 4 Mar 2021 00:07:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B123864F4A for ; Thu, 4 Mar 2021 00:07:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355191AbhCDAHA (ORCPT ); Wed, 3 Mar 2021 19:07:00 -0500 Received: from mga05.intel.com ([192.55.52.43]:40969 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237335AbhCCVRK (ORCPT ); Wed, 3 Mar 2021 16:17:10 -0500 IronPort-SDR: j1K1quAxMPqOSSXqKXoCFfkbWh7b+tUA6mPo+1zL8/cC5wc4hw245lSDE0vwP+Mvfcn9ywcZTj QkFCJbpKQVng== X-IronPort-AV: E=McAfee;i="6000,8403,9912"; a="272282417" X-IronPort-AV: E=Sophos;i="5.81,220,1610438400"; d="scan'208";a="272282417" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2021 13:15:15 -0800 IronPort-SDR: 4GumHzw+bqY2IuEknONcScAZW86HiX+ue90j58IjKak+hmhbzwOuAwfFlCGtOaA4n6eEKtFaub IoJjZGUM6C9g== X-IronPort-AV: E=Sophos;i="5.81,220,1610438400"; d="scan'208";a="406603184" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2021 13:15:11 -0800 Date: Wed, 3 Mar 2021 13:17:26 -0800 From: Jacob Pan To: Tejun Heo Cc: LKML , Joerg Roedel , Lu Baolu , David Woodhouse , iommu@lists.linux-foundation.org, cgroups@vger.kernel.org, Li Zefan , Johannes Weiner , Jean-Philippe Brucker , Alex Williamson , Eric Auger , Jason Gunthorpe , Jonathan Corbet , Raj Ashok , "Tian, Kevin" , Yi Liu , Wu Hao , Dave Jiang , jacob.jun.pan@linux.intel.com Subject: Re: [RFC PATCH 15/18] cgroup: Introduce ioasids controller Message-ID: <20210303131726.7a8cb169@jacob-builder> In-Reply-To: References: <1614463286-97618-1-git-send-email-jacob.jun.pan@linux.intel.com> <1614463286-97618-16-git-send-email-jacob.jun.pan@linux.intel.com> Organization: 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 Hi Tejun, On Wed, 3 Mar 2021 10:44:28 -0500, Tejun Heo wrote: > On Sat, Feb 27, 2021 at 02:01:23PM -0800, Jacob Pan wrote: > > IOASIDs are used to associate DMA requests with virtual address spaces. > > They are a system-wide limited resource made available to the userspace > > applications. Let it be VMs or user-space device drivers. > > > > This RFC patch introduces a cgroup controller to address the following > > problems: > > 1. Some user applications exhaust all the available IOASIDs thus > > depriving others of the same host. > > 2. System admins need to provision VMs based on their needs for IOASIDs, > > e.g. the number of VMs with assigned devices that perform DMA requests > > with PASID. > > Please take a look at the proposed misc controller: > > http://lkml.kernel.org/r/20210302081705.1990283-2-vipinsh@google.com > > Would that fit your bill? The interface definitely can be reused. But IOASID has a different behavior in terms of migration and ownership checking. I guess SEV key IDs are not tied to a process whereas IOASIDs are. Perhaps this can be solved by adding + .can_attach = ioasids_can_attach, + .cancel_attach = ioasids_cancel_attach, Let me give it a try and come back. Thanks for the pointer. Jacob > > Thanks. > Thanks, Jacob