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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56F4FC48260 for ; Thu, 8 Feb 2024 14:34:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9A11C6B0078; Thu, 8 Feb 2024 09:34:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 92A386B007E; Thu, 8 Feb 2024 09:34:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 77C636B0080; Thu, 8 Feb 2024 09:34:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 648366B0078 for ; Thu, 8 Feb 2024 09:34:26 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id D9B901C0808 for ; Thu, 8 Feb 2024 14:34:25 +0000 (UTC) X-FDA: 81768882090.09.03CAF14 Received: from NAM02-DM3-obe.outbound.protection.outlook.com (mail-dm3nam02on2041.outbound.protection.outlook.com [40.107.95.41]) by imf18.hostedemail.com (Postfix) with ESMTP id 157C31C0024 for ; Thu, 8 Feb 2024 14:34:21 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=qP02rFPM; spf=pass (imf18.hostedemail.com: domain of jgg@nvidia.com designates 40.107.95.41 as permitted sender) smtp.mailfrom=jgg@nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1"); dmarc=pass (policy=reject) header.from=nvidia.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707402862; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=VIFlEL6KqjpTDlSEP8XudKkIxz16vybrXCwt9KiDZ4w=; b=i/bi/e+m2vxzvBArfbP5Fri74S2ec29m7A34JMsleHtqFVt9N4hnyD17xmVDwVqfD9VfOZ yz4ZzJrRVswFpxCTcfkIfLfrvMbz7IWX6opmMC1j0loDHrGNfQSccf9JXeTJPluZCGkGiT qXvRSZu/qhZv8iA0ou+24KzJO20Z1/k= ARC-Authentication-Results: i=2; imf18.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=qP02rFPM; spf=pass (imf18.hostedemail.com: domain of jgg@nvidia.com designates 40.107.95.41 as permitted sender) smtp.mailfrom=jgg@nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1"); dmarc=pass (policy=reject) header.from=nvidia.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1707402862; a=rsa-sha256; cv=pass; b=ElChx6vz7PtOukmCurTUjrf+cX9YvXK+vU2SMbPGWBLQ1ucqhCdpidTDUnocX6Qxppey1N 7F0fSvBQ0VFVOZZn/eKwft/GbUdrIIPAb+bldIoLDN4vxB6BT7km3t6A/nd11uVPnDn9lO GbVjSuhrSI+Cp/dKjF6uyk47Sq5PpiQ= ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=dDxSD4cVzVV8CYyXEPT1Z7Jo3Lmqd1i9eWMXmg6fbLHkH+f2tUGDCcN+nvIhp30vdBlVJGp85oRtBhbPj2rthzUmKO8puBQNMng4TgoXbgbMJfQmH1yoq8HUkXBO/Pf2dcyaDolyUTWTDxca4+HBwBhPXkC7Aw2mTyuDOmLakSyy344CZCMoMT6zmkPiypvWOdbpTbBOK5GtzCyt/+Ry17Q4BDfruShWakxa9/xGuSEBqY3HQM7BZhiX8+yGAl4Vzncllm+aFH4VHWyu1fnGz679p4IEugZUYcuFC2fhFrpy92iktT3RjAyg61ut5YPGzvAxYUldlTgMYbqRy6qU2Q== 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=VIFlEL6KqjpTDlSEP8XudKkIxz16vybrXCwt9KiDZ4w=; b=c3yQzsVUNBp7Tl4GPAzk5nmStUOaJji5IHLDF7UDj7g2hxa8qQ6+aeL8iDkDcyX+vC/9tqv6Nj2oH2EIe+wM1AtOTtiZc3/NOFC2G8z/OeBLQVSDjknYReNMoOMeSJwFVTgEe0gb7W5JPxFXeqgL36goQPzYprM4dvWccMC7jvPnSn7tQd8CpyZxBP/FDxS9SHekEAtN7wHhNOM+fnJFWSm+zrHrvBguIgN9Z2MTOC/3+NPPWsLcap9/zBJjJur7Q2jbY1+MkbUsSPCybwXNRxxsCgu1L1kVsnsb8rOqevJ7yXMVgdWA9wSvQ1kmLLuX6U3g8gOlyL3Rw1+ywGffzA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=VIFlEL6KqjpTDlSEP8XudKkIxz16vybrXCwt9KiDZ4w=; b=qP02rFPM5jajXzFmbpTg+L+xXO7svmypVdBFCK6IrmgAu2bzmGygkDVeVc27c0boby0kkYh5xZLn86XxBE3evjKSa5QY4EuISaFJA+TlGXWobwJQg1xVxsCXTEGAucd6YOhBHdCl7ZXF/uDgMUD7rF36DRD7OYQeZdM8/zoFukHPK8AManwB6kWUXBVwSHEGWYzq3JXyXgY3HAZNlmqDnZ0GYdT26yWSDEn4Crh85U3nfSYkSKzPOS2c98u1b5BD/qi8hWlNBL0wMZlN+2u8T59BDe3hYarfltcv3sLOFyLGcNLFuEXsiiXkUwkN+UeWHtDjauZ7GXFPnv92Xz/r7Q== Received: from LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) by MN0PR12MB5932.namprd12.prod.outlook.com (2603:10b6:208:37f::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7292.11; Thu, 8 Feb 2024 14:34:15 +0000 Received: from LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::96dd:1160:6472:9873]) by LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::96dd:1160:6472:9873%6]) with mapi id 15.20.7270.012; Thu, 8 Feb 2024 14:34:15 +0000 Date: Thu, 8 Feb 2024 10:34:14 -0400 From: Jason Gunthorpe To: Catalin Marinas Cc: ankita@nvidia.com, maz@kernel.org, oliver.upton@linux.dev, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, reinette.chatre@intel.com, surenb@google.com, stefanha@redhat.com, brauner@kernel.org, will@kernel.org, mark.rutland@arm.com, alex.williamson@redhat.com, kevin.tian@intel.com, yi.l.liu@intel.com, ardb@kernel.org, akpm@linux-foundation.org, andreyknvl@gmail.com, wangjinchao@xfusion.com, gshan@redhat.com, ricarkol@google.com, linux-mm@kvack.org, lpieralisi@kernel.org, rananta@google.com, ryan.roberts@arm.com, aniketa@nvidia.com, cjia@nvidia.com, kwankhede@nvidia.com, targupta@nvidia.com, vsethi@nvidia.com, acurrid@nvidia.com, apopple@nvidia.com, jhubbard@nvidia.com, danw@nvidia.com, kvmarm@lists.linux.dev, mochs@nvidia.com, zhiw@nvidia.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, David Hildenbrand Subject: Re: [PATCH v6 2/4] mm: introduce new flag to indicate wc safe Message-ID: <20240208143414.GJ10476@nvidia.com> References: <20240207204652.22954-1-ankita@nvidia.com> <20240207204652.22954-3-ankita@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: SA1P222CA0077.NAMP222.PROD.OUTLOOK.COM (2603:10b6:806:2c1::24) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|MN0PR12MB5932:EE_ X-MS-Office365-Filtering-Correlation-Id: 62252bd5-c86b-4b29-27b2-08dc28b306af 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:LV2PR12MB5869.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(396003)(136003)(366004)(346002)(376002)(39860400002)(230922051799003)(1800799012)(64100799003)(451199024)(186009)(5660300002)(2906002)(4326008)(8936002)(8676002)(7406005)(7416002)(41300700001)(83380400001)(86362001)(36756003)(1076003)(26005)(66946007)(66556008)(66476007)(6506007)(316002)(2616005)(6486002)(38100700002)(6916009)(478600001)(6512007)(33656002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?bNZrM9xEU6WI1x70e3Hi91k1B36LyjdRDON1CkDSIlWMwsB1TSBilHWLVRjK?= =?us-ascii?Q?AZUEJrgzmeKzRYBWv1W/rPyDmMWIAeut0aDo9dnJb3JwZ501H32MmtSmJk5a?= =?us-ascii?Q?HCNbM2d552NyGlZ0x8sGo01aDd5YL9b4B6wEUNDJWDss/5g2BAo5ml/aiOJ9?= =?us-ascii?Q?Ge5VW0rVnSbNblN7/200pFW0TcfDcUHfU+8BOHKLcILmgTIl41pVohPfcuzI?= =?us-ascii?Q?xXMnQoNV7G5XqZsGwKC7B/YwTeq9m9cuJ2XTyUcg2q+ZVm3CR6stq5qTQvXS?= =?us-ascii?Q?LfriJ29VELnkcBy15TjHwkZ8HsXSJXml4Fk9X/12ueKzW5qx47JRNXyB59zw?= =?us-ascii?Q?O4do0P3buYrZ+aer9IQNn0YCSsZWx1sHO7ahcUEMoS6QF8LYPO3H3aHsHELU?= =?us-ascii?Q?lKPF54XOnyz2MLoI/tAfUdJJWf1DaDpryoSpnD1GEIG4Z0/SJNAAeham4BYT?= =?us-ascii?Q?s90QkMzI31lK1SKqUCVH2yZR7MyQNpX0pnVw/AjVg6zvXFCMV3OypNoSev9w?= =?us-ascii?Q?owMB9bci+g7Ey3tW5dfv+cDS2vkBGhUwsm0KY7SKufzSBEvfUlCSq0KrmMc6?= =?us-ascii?Q?i1UaAi27O0Zf88GiRo0t5DeXLxstCABoUc0PGupxv9M8KEcts1zUnm7WxPe9?= =?us-ascii?Q?YP+AU7puk9p1cPVUOxosEt1d5WCjiGamxyj914WZajo4b4s5wQx7IYC7Rqvt?= =?us-ascii?Q?GlgwAPdl2lLYYIIrJCk9C+wwreAVg6YOj1XYAJoxA3cSumVjWnesRtqSd25t?= =?us-ascii?Q?rm1b5Ij7ursoaXka1lEbrCAv0U9Cer9d/rgDLhRndAMyeSLjlZMtqveQOLby?= =?us-ascii?Q?61FiDhRJmoNRFSxxBneNaXpEVeMEYiddGIn3ZV5jVb3D5vREcvrxonBdRaxb?= =?us-ascii?Q?QcuH5EZBB73/id2fE9JnlFOyvGr1ftxizxxis6Ug4msh9ahDHqfGd7qlq/Ws?= =?us-ascii?Q?Nhr/8U9whxzxrCHbvcQ98Z2SzpPXwTbI26DqKzciMVD+bqFkP/cTVmBwsZU8?= =?us-ascii?Q?Y00MXkpcqwxt1fUAKDB/ghIOc4JphrnygB22mHYoG8F+cscZ+Hgc8mzKgN8g?= =?us-ascii?Q?Ox0VuM+eGOOkKWj34CUrAXnhEfqynkiIYyNMhMquDvXA3+qBcvqibZCp6xNA?= =?us-ascii?Q?ROHMWHiM73tasVoChj4Cin1Ft0tanODvj18XCGjyL/IlukaR0fqc7M4vSoX8?= =?us-ascii?Q?c5pq9FODp85Q7+xC1APP4NIB9PTFl9pmT6Bb4/ePSgiNhmcXxxAFygQ1xVpR?= =?us-ascii?Q?F8v1P+rLOXygMy6p2+/MuKRDc3Q3XNYtE6XMsWaECKY5mGnowP7bgOKDLJBo?= =?us-ascii?Q?ZXczubaQObPchNjNeTQ44AhBXoXMvF8EEonqmAHcBS/nK0jofPXmbS48OMTe?= =?us-ascii?Q?KkQOUW/nZIHrqGM4GMrP6MqpoxXbXBXUmZ0Y2KzbO55jn/5yJKUKGpIrgDJ+?= =?us-ascii?Q?a3rrLKWyHRAXiYLizlW3uD/6l7p6xl0+b5gKnNvJfzdv3fRNjE+QtmhE7NEy?= =?us-ascii?Q?vtA+wjxkKuCkCiGcSOcktqNn/aMncuYA8b5cmJz0UAGAiCRKof5Nr4c6mjSv?= =?us-ascii?Q?bmGKcb+29fayRdYGK+DL8juRyMghPaBhmM6nlzea?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 62252bd5-c86b-4b29-27b2-08dc28b306af X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Feb 2024 14:34:15.7511 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: scbb7YXhBWFTvqlTFNPNCkCK4/uucn/uup/xLrFQqZ7lMbUuB2TkE1c/9MaM1woC X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN0PR12MB5932 X-Rspamd-Queue-Id: 157C31C0024 X-Rspam-User: X-Stat-Signature: fda3eebkxc6887ptiyeba3wm5y7a7yix X-Rspamd-Server: rspam01 X-HE-Tag: 1707402861-420259 X-HE-Meta: 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 Qs2V8O2s i3M/pFtV5PelCl601ovcL2pUPFP65vgK1CnZPCcI0KEV20b4f/0YAQKOpLA4Nn8MLw03TK5nsweC446B7xL3xzHJ/t8X902MTM9rmubHZMAH7HNILk2BoT4XuK/Y3cUmGpyeojuQEbp/bgbIdVHsvGAGYtuAoxS6shPvAMDxGKPdUZKlyyBS5UCDHX/HuLw0iU0hsxYr0En3SUrnH7i+TpBimUj+7RAHO8NHOtGfZk0Xgyg8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Feb 08, 2024 at 01:03:27PM +0000, Catalin Marinas wrote: > On Thu, Feb 08, 2024 at 02:16:50AM +0530, ankita@nvidia.com wrote: > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index f5a97dec5169..884c068a79eb 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -391,6 +391,20 @@ extern unsigned int kobjsize(const void *objp); > > # define VM_UFFD_MINOR VM_NONE > > #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ > > > > +/* > > + * This flag is used to connect VFIO to arch specific KVM code. It > > + * indicates that the memory under this VMA is safe for use with any > > + * non-cachable memory type inside KVM. Some VFIO devices, on some > > + * platforms, are thought to be unsafe and can cause machine crashes if > > + * KVM does not lock down the memory type. > > + */ > > +#ifdef CONFIG_64BIT > > +#define VM_VFIO_ALLOW_WC_BIT 39 > > +#define VM_VFIO_ALLOW_WC BIT(VM_VFIO_ALLOW_WC_BIT) > > +#else > > +#define VM_VFIO_ALLOW_WC VM_NONE > > +#endif > > Adding David Hildenbrand to this thread as well since we briefly > discussed potential alternatives (not sure we came to any conclusion). FWIW, with my mm hat on: Reviewed-by: Jason Gunthorpe But I'm interested if David has an alternative. We don't have a shortage of bits here so I'm not sure it is worth much fuss. Jason