From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1F1CF217723 for ; Tue, 9 Dec 2025 14:40:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765291236; cv=none; b=PC8lqSTdFFJ66LTlBBdUvmWRpizTEFs78nycNplK1Q5v92TjsbWfqKxdaubR/Kfhz8xUww6oObNuUKS2P/nUfzOKeYjD67FWR6gP4qtoW75MUJ7sY7uVzXgqvuR/NmVi78n9AlRCoZfQUwlWCF0cI1LB4ViAASONkAgG95eYW7k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765291236; c=relaxed/simple; bh=JsueLNfctsAxP/qrHfn8CyFAqIvcCzcK2AguURbSEkg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OukdmBRMsq44E7HVFjX2GApyZj9DVB+8z/D19T9DnsSDyEYygVDse6N5hH9fqvxEou9J6h8OSkrKCq0M0WTz3zyjXkytzBMPy8Vu/nNUr5AK7TERszuTzLqPH4bokL3vjF+c56L6EuCcoX1wzXw2EiGNUy8ABNLkitokzWWsM8o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 EDF7E175D; Tue, 9 Dec 2025 06:40:25 -0800 (PST) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DF16A3F73B; Tue, 9 Dec 2025 06:40:29 -0800 (PST) Message-ID: <41bcd0d2-d5b8-4f3d-b0b3-132387f547ed@arm.com> Date: Tue, 9 Dec 2025 14:40:28 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 00/38] arm_mpam: Add KVM/arm64 and resctrl glue code To: James Morse , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Dave Martin , Koba Ko , Shanker Donthineni , fenghuay@nvidia.com, baisheng.gao@unisoc.com, Jonathan Cameron , Gavin Shan , rohit.mathew@arm.com, reinette.chatre@intel.com, Punit Agrawal References: <20251205215901.17772-1-james.morse@arm.com> From: Ben Horgan Content-Language: en-US In-Reply-To: <20251205215901.17772-1-james.morse@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi James and all, As James is otherwise occupied, I am planning to post a follow up version of this series once it's had time to be reviewed. I will be posting my own review comments; please give them extra scrutiny. On 12/5/25 21:58, James Morse wrote: > This is the missing piece to make MPAM usable resctrl in user-space. This has > shed its debugfs code and the read/write 'event configuration' for the monitors > to make the series smaller. > [...] > > This series is based on arm64/for-next/core, and can be retrieved from: > https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git mpam/glue/rfc > > There is no snapshot branch - this is it! > I'll push the extras branch once I've gotten a handle on the DT shaped mess in > there. One major departure from the previous snapshot branches referenced in the base driver series is that the same MPAM setting are used for kernel-space and user-space. That is, MPAM1_EL1 is set to the same value as MPAM0_EL1 rather than keeping the default value. The advantages of this are that it is closer to the x86 model where the closid is globally applicable, all partids are usable from user-space and user-space can't bypass MPAM controls by doing the work in the kernel. However, this causes some priority inversion where a high priority task waits to take a mutex held by another whose resources are restricted by MPAM. Thanks, Ben