From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 724E3387375; Thu, 6 Aug 2026 05:23:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785993836; cv=none; b=BoGFM/z3ZCwMZY0950ukHcz0fISGivp4oZEF8QMnN9WmFPI1RXRP49S9jDIa2Kuq8sUQ3yukjLaVl6wSVyOFDgDqS/E3o3Xg/io34fNBS/mgs6JRNPPWaWmokC9Q+Gn8ZsqwD8ZV3Ugf2cNk6GRkQgQprjUQ3xLuE26Z6ejMGHM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785993836; c=relaxed/simple; bh=LLzoqJ6iWkdaYWF6YDdx39wtk9QuB4fEWZpJHr04Xio=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MG/dxTMYQm7fHHVnQK2gVuTDlNDQeCKbchxsgkopuVXf6OdAjwvPy4op3MYSVNlRB7pO306EkJke8XHgmSzkzhKBbfoUugsTVA12r6NXZvzeU0TNFEsIxPieZu3A0lmM1wgQGcJSNsPJySRcbaUJfsUWdKZ3P7cj31LL5DJKx9A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kxx1fg/O; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kxx1fg/O" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B17B71F000E9; Thu, 6 Aug 2026 05:23:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785993835; bh=nGUsqZ9RJANQTX4cFkBlQkPsf7GNKP6d1ba13+NtzNY=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=kxx1fg/O5f0UuVL1DBWUTFwB6czE67TjponNaQJ6hDBbO7K3J20+B+gtnpGtE2EHp rAYyji6NuNaTUGeqF46kTwC2M7YbgXsjwKLvmeWuFfrx6RJwW8ThPiF9e3AlBewIdu Yt58roYQMaKAnSMS6u4ntZnpmNXP5ntAEepXmcWQvZGKEvePNd8juzw+UHlNuwjUhc +eg931sMy/6/d1swtuJORhOO74AZxy6WXG5pgjO/NGSCggG2H4xNnuYHqv/Ajilgby dadyrRTqc3LSA0sWym7qXm1iqql6EANUinvBX3hPHY2ZA7RyixT1QTefSp8DKu0eCh EkFhBAW/82RLQ== Date: Wed, 5 Aug 2026 22:23:53 -0700 From: Drew Fustini To: Zhanpeng Zhang Cc: ben.horgan@arm.com, 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 Subject: Re: [RFC PATCH 0/7] riscv: iommu: Add QoS ID support for resctrl device assignment Message-ID: References: <20260714130657.46963-1-zhangzhanpeng.jasper@bytedance.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260714130657.46963-1-zhangzhanpeng.jasper@bytedance.com> 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 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/