Received: by 2002:a6b:fb09:0:0:0:0:0 with SMTP id h9csp753299iog; Fri, 17 Jun 2022 12:50:16 -0700 (PDT) X-Google-Smtp-Source: AGRyM1ud4++NHQi39kBpdMi4BzWALj51RhxppAC2PLIpZpe9TltHOfNMpm16DzjonQ/D8gYGzpED X-Received: by 2002:a17:90b:4c10:b0:1e8:d377:4998 with SMTP id na16-20020a17090b4c1000b001e8d3774998mr23527988pjb.227.1655495415954; Fri, 17 Jun 2022 12:50:15 -0700 (PDT) Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id u69-20020a638548000000b0040c42c926aesi1488352pgd.460.2022.06.17.12.50.03; Fri, 17 Jun 2022 12:50:15 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@intel.com header.s=Intel header.b=g0ms45Ha; arc=fail (signature failed); spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235797AbiFQTcj (ORCPT + 99 others); Fri, 17 Jun 2022 15:32:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231304AbiFQTch (ORCPT ); Fri, 17 Jun 2022 15:32:37 -0400 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E26EA185; Fri, 17 Jun 2022 12:32:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655494352; x=1687030352; h=date:from:to:cc:subject:message-id:references: in-reply-to:mime-version; bh=3gzeJtqcX0o/BkQAq9o37TbkBECXFUGNTf+Benowf8I=; b=g0ms45Ha6pI/xqOilC0Tl6K9r9KMAtusPCX1Um/9tSw5UlMJiQZtdK7C Fsk2zWcUBTX7kL65OFJ9njB2pj85wgRPIZCuybq1ySCEhE6eLEcsxZAxf Uj+YZZVd0Dc7twwkc/6J46qa2dCWF0ihw0Pt5avwpyUFiMqn26KAL3GDo 6LF7eEDAKBsXAYl5pKMNQqgI6fXTAH+1dIHgPcjfFwAcDN1nVSwj9f/G+ XLO3lT4fimUPjhYGIMOSAqCC65X9l9XiMROAedUndVAIXvZYeBIyfxH5h 724MIwhM2KCOU5b+Nim185B+keeiUauksBtQ7s0oROVt+1OCcu7QPXwwt w==; X-IronPort-AV: E=McAfee;i="6400,9594,10380"; a="341255386" X-IronPort-AV: E=Sophos;i="5.92,306,1650956400"; d="scan'208";a="341255386" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Jun 2022 12:32:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,306,1650956400"; d="scan'208";a="912731828" Received: from fmsmsx604.amr.corp.intel.com ([10.18.126.84]) by fmsmga005.fm.intel.com with ESMTP; 17 Jun 2022 12:32:32 -0700 Received: from fmsmsx609.amr.corp.intel.com (10.18.126.89) by fmsmsx604.amr.corp.intel.com (10.18.126.84) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.27; Fri, 17 Jun 2022 12:32:31 -0700 Received: from fmsedg601.ED.cps.intel.com (10.1.192.135) by fmsmsx609.amr.corp.intel.com (10.18.126.89) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.27 via Frontend Transport; Fri, 17 Jun 2022 12:32:31 -0700 Received: from NAM12-MW2-obe.outbound.protection.outlook.com (104.47.66.44) by edgegateway.intel.com (192.55.55.70) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2308.27; Fri, 17 Jun 2022 12:32:31 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=oMcr5QkDY239IIa6J/l5jUTARJYJmqJ9QS92ciGBDJ8NZ1+QP9woAsZO1TpMhwlRvvB7RGvz2D7Xy7UBEYWB159bAtzaGgWmL3u9th27VHlkI1Fu7OzR2GRInu0NBK9oLn2sRRQ0qlH2HVUDaBDo0FWwdViUcy10U6ol17PuLTyhAjo0LINbnrAs/+pqK9wrRbR+1cCOzW4/GF76GfWoEXAgEQEncRjtC4jz3mmYCMf/uqcEshZ75OtrZ6YpU0HSr/+sxqtrUF0hgr6XcmZ1jYD8Jg06wIKu3J9kUHp6CoKftrfa/2tF+VFfOWsragavUYcK9/IRDLBay8H2+I4M5A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=PRMh9my0YNiucuTkpRvFn7oIV3z9+oVbQ1gDmDsoOeo=; b=DfXmdoWNScg3SG9hzgHXY24nUaQ3eOlj2UdQfqHBzmvH81gFpRXVdGUuu2oCBKLENrp388XtEcqW6+cB8FyCDX7tdoE0tfwTenPZYvxbjMnzT3R4C7sm3esrAbHUrnPuY+qrgYdEx2mSDUVMPBnRkZ9f9AriRfLJXNoHsh95LlGdfMXKwghUY02322eZkjCRwJhOQwm6W2EVbkL4AEmde7elfZMARuOJvEsJmjmbjAozdkjk2ysg4Z3v2nU6LgGfaLjYSZHKLNuIyTfmTcg3Hl4KyY/ki9+1vyMExk7vT/bxbKr17hGx/9Cs181aBC6n5VBF0uRkbXYtE56GQv4bhw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from MWHPR1101MB2126.namprd11.prod.outlook.com (2603:10b6:301:50::20) by BN9PR11MB5289.namprd11.prod.outlook.com (2603:10b6:408:136::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5353.15; Fri, 17 Jun 2022 19:32:30 +0000 Received: from MWHPR1101MB2126.namprd11.prod.outlook.com ([fe80::f50c:6e72:c8aa:8dbf]) by MWHPR1101MB2126.namprd11.prod.outlook.com ([fe80::f50c:6e72:c8aa:8dbf%7]) with mapi id 15.20.5332.023; Fri, 17 Jun 2022 19:32:30 +0000 Date: Fri, 17 Jun 2022 12:32:28 -0700 From: Dan Williams To: Alison Schofield , Jonathan Cameron CC: "Williams, Dan J" , "Weiny, Ira" , "Verma, Vishal L" , "Ben Widawsky" , Steven Rostedt , "Ingo Molnar" , "linux-cxl@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 2/3] cxl/mbox: Add GET_POISON_LIST mailbox command support Message-ID: <62acd6cc72637_844b129463@dwillia2-xfh.notmuch> References: <382a9c35ef43e89db85670637d88371f9197b7a2.1655250669.git.alison.schofield@intel.com> <20220617150508.0000266a@Huawei.com> <20220617162935.GA1532720@alison-desk> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20220617162935.GA1532720@alison-desk> X-ClientProxiedBy: MWHPR11CA0009.namprd11.prod.outlook.com (2603:10b6:301:1::19) To MWHPR1101MB2126.namprd11.prod.outlook.com (2603:10b6:301:50::20) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 6e5f4d13-27dd-4f75-f572-08da50981e3d X-MS-TrafficTypeDiagnostic: BN9PR11MB5289:EE_ X-LD-Processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:MWHPR1101MB2126.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230016)(366004)(186003)(498600001)(82960400001)(8676002)(66556008)(110136005)(5660300002)(9686003)(54906003)(6506007)(26005)(66946007)(83380400001)(4326008)(6512007)(38100700002)(2906002)(6486002)(86362001)(15650500001)(316002)(66476007)(8936002);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?N2Cdqrcwzner7Ld3JMvYY8XowxYiGhuW2j+g6P0CVO4rZadsCqVOotnkM/Be?= =?us-ascii?Q?TgPXAt9nUT9Qm/xKCwxG+Qh8C12IXVa+gexhFz194zf0CucQT5xZZTDrG4iW?= =?us-ascii?Q?/lTYiUF9Ow+AEJMhYY8i6z9SeozkyuG4IZOtK9bxrSqzSbg7yqXW+Ibbp1bV?= =?us-ascii?Q?I6yqJ6C8yYJjNpwy8xU0Sny0C2c0GmlJk0HB4iPObHRn3SE47A5ESrHLv7lq?= =?us-ascii?Q?HXAFqYqYrZJmeCYVw5dXtFimx0FP/jvom94PGlcii1DH3YNRGZbhOJSY8vA1?= =?us-ascii?Q?JsMzQVZggGgPLePnAAnRTMpfCwNLZheYXJqXJNkwgGUWdj75JowCH9qEAFgr?= =?us-ascii?Q?qLdpi5JMeENOlXHZxEa6q9bCKc+CTN0oxNJS4flMellsIMSShRmVKfCz3vt0?= =?us-ascii?Q?Ak7aV0xhDKc6AmzINFkm9z1zy2/D/5Yl9+lXO3cVzmlrUwq5ZwFU2jV4YFfS?= =?us-ascii?Q?VTgFxIlmW9qQixyJae1uP+EP8EUQ5o1q+sZpDpIfEpF37b29Edwcfc6V/6PZ?= =?us-ascii?Q?IpNxT8kWZ01cuF93iJoOzIR33y5Av9cLizGQpBhlrz0PotZ8NT1l2loyS1T9?= =?us-ascii?Q?J/9yo+2sGU4NxJyWtFCBkDn+H969LesUs56jWIA7cunsdq8dJcIKB0KK09LJ?= =?us-ascii?Q?gcWJ3sSnUpL7WUpyQEbjTTWD8afYe01MUNMP6b5fRWQN/icDK4Thgvgwxpto?= =?us-ascii?Q?a19NtIdfdSzJilipQ5zWul5FkmHnbV9MEvRkXwLkWQjSwDNVaR1gHBF6p//B?= =?us-ascii?Q?h41OWV9KUxWp9ETelLBdRgQct5nWONCJ3IoKDbnFUMAJ+cVgMwGxYIOXR+Fy?= =?us-ascii?Q?hVj5c+eC9zvn91fGGDjSCxgshgo3gjXtJ+vM4xtWmayn0Bp8lfgKfyRLz+rD?= =?us-ascii?Q?NJi3Q0IUE43qmxaPlneE+GCDsW9tUWLMuvO7QOdDPPaIjnhElDzwIRnjOUz4?= =?us-ascii?Q?aaUIrcCIELkTq2d+wipMKinPEuJTcFfEJQ7zEKZb8O4vnyNPmHOMvk91wx+/?= =?us-ascii?Q?BmMkfPA6QjhciDvRsYhzzdRopUUFIsFPECkzDkTcCOZXZgOqBj6ipffPxQdS?= =?us-ascii?Q?1jB3yl+nCcpRaCFjvF2cSC83V7i+w4mPCaYjAYg6WBR/9zHw6d4Qx6JaIhC2?= =?us-ascii?Q?138WQtAuHZNCz9NUUJuGxNUbYqLn3DND294/lxccTyUcE3FUJ6gedWcz+sSK?= =?us-ascii?Q?DdaNLuim4ZPIpt42DS9bj4C7a6Wf6HjOtyeu6AnjvcTseFTY9UB6hOkX2fmx?= =?us-ascii?Q?FyfAFekEuEdAB5iefQDovly0qX4JYY3XdMGWKND83Jc7m76HpcXO3GSP9xOj?= =?us-ascii?Q?73KDMNQVw9VBUqq1yfiqEjOFEir57VUiNfdrDq1CNJjSF5Haj1AocTFxp2xz?= =?us-ascii?Q?nts2A0G5NuH076mRg4tNpO/cCta+q73++paBKDtWQTrku0LXXN5UxE8ZTrlR?= =?us-ascii?Q?xEHlHxpn8KDtxiOUPaM/ApDZB6obQt4J/VCLFeHW93zPanz/+GNDW9DxrFAU?= =?us-ascii?Q?AnCKilJQd9qUAr6AU8TaSAcaIm9S1amnxk7w8S912UE+d9pXPj+uwGjGnlXh?= =?us-ascii?Q?c8dWm0k99SlujOx4vtrFDTrxKYe5mFVHDYr4efCCaH2KwYy/TyfFnyBCRO+9?= =?us-ascii?Q?16FhrH3xJGu+98eMRJgKUkvrzVnCmwQ6IEbC82zfS5dzTFIiz+9UvhQumeWM?= =?us-ascii?Q?9KojM1W6ArIu0nbtEaT6XlUlPawlxwMlait/bG/WMSuMTb4PuHxREr5kOLKM?= =?us-ascii?Q?62KBo7+KbnemVbPP0pPh0hNPCtF2t74=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 6e5f4d13-27dd-4f75-f572-08da50981e3d X-MS-Exchange-CrossTenant-AuthSource: MWHPR1101MB2126.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Jun 2022 19:32:30.0224 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: cdclxWAlWAfSIANMn/qEo+H4VP/mcpbQCYp/gX84+/jta4grupSW9blo82W4+QMxznXlRekXJ+RtT2qsYlVJuKjbo+tBtMKCXyZSe2aWdEA= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN9PR11MB5289 X-OriginatorOrg: intel.com X-Spam-Status: No, score=-5.0 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alison Schofield wrote: > On Fri, Jun 17, 2022 at 07:05:08AM -0700, Jonathan Cameron wrote: > > On Tue, 14 Jun 2022 17:10:27 -0700 > > alison.schofield@intel.com wrote: > > > > > From: Alison Schofield > > > > > > CXL devices that support persistent memory maintain a list of locations > > > that are poisoned or result in poison if the addresses are accessed by > > > the host. > > > > > > Per the spec (CXL 2.0 8.2.8.5.4.1), the device returns this Poison > > > list as a set of Media Error Records that include the source of the > > > error, the starting device physical address and length. The length is > > > the number of adjacent DPAs in the record and is in units of 64 bytes. > > > > > > Retrieve the list and log each Media Error Record as a trace event of > > > type cxl_poison_list. > > > > > > Signed-off-by: Alison Schofield > > > > A few more things inline. > > > > Otherwise, can confirm it works with some hack QEMU code. > > I'll tidy that up and post soon. > > > > > +int cxl_mem_get_poison_list(struct device *dev) > > > +{ > snip > > > + > > > + trace_cxl_poison_list(dev, source, addr, len); > > > > Need to mask off the lower 6 bits of addr as they contain the source > > + a few reserved bits. > > > > I was confused how you were geting better than 64 byte precision in your > > example. > > > Ah...got it. Thanks! > > > > + } > > > + > > > + /* Protect against an uncleared _FLAG_MORE */ > > > + nr_records = nr_records + le16_to_cpu(po->count); > > > + if (nr_records >= cxlds->poison_max) > > > + goto out; > > > + > > > + } while (po->flags & CXL_POISON_FLAG_MORE); > > So.. A conundrum here. What happens if: > > > > 1. We get an error mid way through a set of multiple reads > > (something intermittent - maybe a software issue) > > 2. We will drop out of here fine and report the error. > > 3. We run this function again. > > > > It will (I think) currently pick up where we left off, but we have > > no way of knowing that as there isn't a 'total records' count or > > any other form of index in the output payload. > > Yes. That is sad. I'm assume it's by design and CXL devices never > intended to keep any totals. > > > > > So, software solutions I think should work (though may warrant a note > > to be added to the spec). > > > > 1. Read whole thing twice. First time is just to ensure we get > > to the end and flush out any prior half done reads. > > 2. Issue a read for a different region (perhaps length 0) first > > and assume everything starts from scratch when we go back to > > this region. > > Can you tell me more about 2 ? > > Also, Since posting this I have added protection to this path to ensure > only one reader of the poison list for this device. Like this: > > if (!completion_done(&cxlds->read_poison_complete); > return -EBUSY; > wait_for_completion_interruptible(&cxlds->read_poison_complete); > ...GET ALL THE POISON... > complete(&cxlds->read_poison_complete); Since this runs in the context of the requester a completion feels out of place. What this probably wants is a mutex() protecting the state machine of the Media Error Record retrieval and the "more" flag. > > And will add the error message on that unexpected _FLAG_MORE too. > > Alison > > > > Jonathan > > > > > > > > + > > > +out: > > > + kvfree(po); > > > + return rc; > > > +} > > > +EXPORT_SYMBOL_NS_GPL(cxl_mem_get_poison_list, CXL); > > > + > > > struct cxl_dev_state *cxl_dev_state_create(struct device *dev) > > > { > > > struct cxl_dev_state *cxlds; > >