From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout01.his.huawei.com (canpmsgout01.his.huawei.com [113.46.200.216]) (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 8C26A3AC00 for ; Wed, 15 Apr 2026 01:27:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.216 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776216447; cv=none; b=Sc1rHhP1/NwLPtLRdSl4d3DiQ2xi/we7aYsYShUrBn/Qx65Vd3cDYhwIxlnMjyVO1d/epxz8VBHUFayvOSApc5HTh5z8i8yf/EBzh5mnlTPP66EBhSQzvvqI/7WcJVvh7RMCujPjGXcERTC8i/t0tYobVmPWB6LRZ/Ne/vHHLxE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776216447; c=relaxed/simple; bh=SEUREO2L7VZ/FiDXJOeWDJYYXDan/YnwRfSw3hPj7J8=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=P/JyGPn5RG/MeKeYWo2Ex8vRdtWcTAsrphS+MUx8bR+Tiy+tfB6Ta5IKNMW1uhxTcJA33pcGMklYd3EzyxOGIADS6XCt5H6yVbMQzBlUibK7r8Uabnw481n+Zba7elKfAuQOus2k9Ubv2PG9kez8O2XqalD66eHwAtROuENOCRs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=h-partners.com; dkim=pass (1024-bit key) header.d=h-partners.com header.i=@h-partners.com header.b=axN/6JiD; arc=none smtp.client-ip=113.46.200.216 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=h-partners.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=h-partners.com header.i=@h-partners.com header.b="axN/6JiD" dkim-signature: v=1; a=rsa-sha256; d=h-partners.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=8XtA1EyYgn41uAU/MTEXCY/CsCra52HysC3sbmkEf68=; b=axN/6JiDV8CeNDO3m1v/grb3Tl/1S2uz4IWT52lRujIhut/lnAVhip8Yg7MqyKMYMyW/VJCek lCSb9pZeT6nqj3B8yf9lGRZRS2j7B/WrzSDFAihXlSJ4M6+nBkr+Vo1QeOrNuUjYxe1q9Ex7Utj YzPLEsTmjETGsaSI01aBj/Q= Received: from mail.maildlp.com (unknown [172.19.162.223]) by canpmsgout01.his.huawei.com (SkyGuard) with ESMTPS id 4fwNdQ5yZMz1T4G8; Wed, 15 Apr 2026 09:21:14 +0800 (CST) Received: from kwepemf100008.china.huawei.com (unknown [7.202.181.222]) by mail.maildlp.com (Postfix) with ESMTPS id 0575440572; Wed, 15 Apr 2026 09:27:15 +0800 (CST) Received: from [10.174.179.37] (10.174.179.37) by kwepemf100008.china.huawei.com (7.202.181.222) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Wed, 15 Apr 2026 09:27:13 +0800 Message-ID: Date: Wed, 15 Apr 2026 09:27:12 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [Question mpam mpam/snapshot+extras/v6.18-rc1] Question with Configuring iommu_group in 'task' Content-Language: en-US To: Ben Horgan , James Morse CC: Qinxin Xia , , , , , , , , , , , , , , , , , , , , , , , , Linuxarm References: <08aacacc-e3e5-4e97-858b-cbcbdb9a1fcf@arm.com> <7b2681c3-9ef7-4882-ba57-2503934e2759@huawei.com> <0d578c61-1341-4149-9e8c-936ea0ce0c50@arm.com> From: Zeng Heng In-Reply-To: <0d578c61-1341-4149-9e8c-936ea0ce0c50@arm.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To kwepemf100008.china.huawei.com (7.202.181.222) Hi Ben, On 2026/4/13 23:02, Ben Horgan wrote: > Hi Qinxin, > > On 4/3/26 03:44, Qinxin Xia wrote: >> >> >> On 2026/3/27 18:47:49, Ben Horgan wrote: >>> Hi Qinxin, >>> >>> On 3/27/26 10:21, Qinxin Xia wrote: >>>> >>>> Hello everyone! >>>> >>>> In earlier versions, mpam supports the configuration of iommu_groups. >>>> >>>>   823 static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of, >>>>   824                                     char *buf, size_t nbytes, >>>> loff_t off) >>>>   825 { >>>>   826         struct rdtgroup *rdtgrp; >>>>   827         int iommu_group_id; >>>>   828         bool is_iommu; >>>>   829         char *pid_str; >>>>   830         int ret = 0; >>>>   831         pid_t pid; >>>>   832 >>>>   833         rdtgrp = rdtgroup_kn_lock_live(of->kn); >>>>   834         if (!rdtgrp) { >>>>   835                 rdtgroup_kn_unlock(of->kn); >>>>   836                 return -ENOENT; >>>>   837         } >>>>   838         rdt_last_cmd_clear(); >>>>   839 >>>>   840         if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED || >>>>   841             rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) { >>>>   842                 ret = -EINVAL; >>>>   843                 rdt_last_cmd_puts("Pseudo-locking in progress\n"); >>>>   844                 goto unlock; >>>>   845         } >>>>   846 >>>>   847         while (buf && buf[0] != '\0' && buf[0] != '\n') { >>>>   848                 pid_str = strim(strsep(&buf, ",")); >>>>   849 >>>>   850                 is_iommu = string_is_iommu_group(pid_str, &iommu_group_id); >>>> >>>> What puzzles me is why we would put it under 'task'—this seems a little >>>>   strange to users.It seems they are not related.Why don't we add a new >>>> interface like 'iommu'? >>> >>> I think it is likely that this interface would change if upstream support is added. >>> >> >> I have done some work in this direction before, and I will release an >> RFC later for further discussion.:-) > > Looking forward to seeing it. > > Ben > Following the current SMMU approach, I've submitted several bugfix patches for the MPAM driver, but haven't received any review feedback yet. To avoid these being overlooked, I'd like to kindly remind to take a look: v2: https://lore.kernel.org/all/20260414032610.1523958-1-zengheng4@huawei.com/ v1: https://lore.kernel.org/all/20251107063300.1580046-1-zengheng4@huawei.com/ Additionally, I'd like to check on the status of this branch — is it still actively maintained? It would be helpful to understand the future plans for MPAM development. Thanks for your time, Zeng Heng