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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 933C7C55ABF for ; Thu, 6 Aug 2026 08:42:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=RIxyCL5x2JjrhvwctAjra1uf6PTuo7FLRy7NyEp49A0=; b=41lb/c8bZVV1Ma YLnLgW+USLjlEbc4OxGBjNfovWz1BjCQIv2Y38DSRyNT9mDWfvfaNy3PDzivAWUEeYGNEMuf0n2LX G257v8uz9p9wcFtJHR+oXDM8tuHds6jVWW2Jx8QwgJwd8n7pPuzxokgmtnJ9t8Hu8DdVWCohlQ3Wq l7uTeb0hjVYQ2/S1nbkRBiJZT0VqkGhiPECKjBiIlD+YuKbJ1NB5RydPGf4Z+zzwEdswGehvDuRcj z57r7SiMt3pzZVF24PkTzbl6S71mi4lDK+j2a1dELhAOgehfRoPOX73L3iVt50CVaAoUXRVmxpFTK JUHrgB7R7m+0hrLPV4Ug==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrtgK-00000005GaP-3jVJ; Thu, 06 Aug 2026 08:42:28 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrtgI-00000005Ga1-03IF for linux-riscv@lists.infradead.org; Thu, 06 Aug 2026 08:42:28 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B8811153B; Thu, 6 Aug 2026 01:42:18 -0700 (PDT) Received: from [10.2.212.8] (e134344.arm.com [10.2.212.8]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 81F433F632; Thu, 6 Aug 2026 01:42:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1786005742; bh=1XZ52c7N7R/7ik+1Q56O2gFc7n1LYmIvcHRd9KWsOdo=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Vk3YFbseN1J/KkpXJV6XxeMhp8z09cM7QKEaGOWthnB2rK15LrGgVvARUQKfSIB3A q+/JfafIf6kUrbpn/GxsrT0SfxqyDag4S4foyW9/Kksq3ryx9lyhrhSqMaGBY5RWAa Z36t681xIH1xquFeoaBivxQxzxvg4wMqdvfwdNBs= Message-ID: <7cf591e8-e182-447f-9808-d8e328d28f79@arm.com> Date: Thu, 6 Aug 2026 09:42:11 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 0/7] riscv: iommu: Add QoS ID support for resctrl device assignment To: Drew Fustini , Zhanpeng Zhang Cc: xiaqinxin@huawei.com, zengheng4@huawei.com, palmer@dabbelt.com, tony.luck@intel.com, reinette.chatre@intel.com, tomasz.jeznach@linux.dev, will@kernel.org, robin.murphy@arm.com, pjw@kernel.org, aou@eecs.berkeley.edu, alex@ghiti.fr, Dave.Martin@arm.com, james.morse@arm.com, babu.moger@amd.com, corbet@lwn.net, shuah@kernel.org, jgg@ziepe.ca, kevin.tian@intel.com, cuiyunhui@bytedance.com, yuanzhu@bytedance.com, iommu@lists.linux.dev, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, x86@kernel.org References: <20260714130657.46963-1-zhangzhanpeng.jasper@bytedance.com> Content-Language: en-US From: Ben Horgan In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260806_014226_447685_923EE554 X-CRM114-Status: GOOD ( 13.34 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Hi Drew, On 06/08/2026 06:23, Drew Fustini wrote: > On Tue, Jul 14, 2026 at 09:06:50PM +0800, Zhanpeng Zhang wrote: >> This RFC extends RISC-V CBQRI/resctrl support to external requesters >> behind a RISC-V IOMMU. > [..] >> Open questions for this RFC: >> >> * whether a common resctrl "devices" file is the right ABI for >> associating external requesters with a resource group; > > I think a separate file is the right approach to avoid confusing iommu > groups with pids. > > I should note that James Morse had an ARM MPAM "extras" tree [1] which > carried an iommu_group assignment interface, using the same > iommu_group: format, but writing it to the tasks file. However, Ben > Horgan clarified back in March [2] in a reply to Qinxin Xia that it is > no longer maintained. Ben also wrote that the interface would likely > change upstream. I've added Ben Horgan and Qinxin Xia to the CC list so > hopefully they can chime in. I haven't thought about the interface much but Reinette let me know here [1], with good reasons, that we should consider the format of the tasks file fixed. Thanks, Ben [1] https://lore.kernel.org/all/f9b08563-4958-4f3c-ad6c-1e7fa3047896@intel.com/ > > I plan to review the patches in this series further but I didn't want to > delay any further in pointing out the above. > > Thanks, > Drew > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/log/?h=mpam/snapshot%2Bextras/v6.18-rc1 > [2] https://lore.kernel.org/lkml/d13fdc75-b647-44f3-9657-d592353e8a1a@huawei.com/ _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv