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 D47ACC369AB for ; Mon, 21 Apr 2025 16:04:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9373E6B0008; Mon, 21 Apr 2025 12:04:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E69E6B000A; Mon, 21 Apr 2025 12:04:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 711156B000C; Mon, 21 Apr 2025 12:04:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 512D36B0008 for ; Mon, 21 Apr 2025 12:04:01 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id CE9A4C0811 for ; Mon, 21 Apr 2025 16:04:02 +0000 (UTC) X-FDA: 83358522324.07.328E9C6 Received: from NAM12-MW2-obe.outbound.protection.outlook.com (mail-mw2nam12on2069.outbound.protection.outlook.com [40.107.244.69]) by imf10.hostedemail.com (Postfix) with ESMTP id B6AE7C0020 for ; Mon, 21 Apr 2025 16:03:59 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=tjwGuzPF; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf10.hostedemail.com: domain of ankita@nvidia.com designates 40.107.244.69 as permitted sender) smtp.mailfrom=ankita@nvidia.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1745251439; a=rsa-sha256; cv=pass; b=GxGIh8LSI/aznm2vIoO0uK90b9m27ZFLK5S03dod2Z7kq+vSRfGhGX5zKj5I8EZ/KZMVy3 LUsEa9nBs+i46Yb6fKDKR5GOzH7nl5KmVw1UJzqT2+GAbmJsMDpIxU+/FN36DwetJBOWxX 0WXcFnlle8+rcvePSHlDJ+46oqNqY8k= ARC-Authentication-Results: i=2; imf10.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=tjwGuzPF; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf10.hostedemail.com: domain of ankita@nvidia.com designates 40.107.244.69 as permitted sender) smtp.mailfrom=ankita@nvidia.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1745251439; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=dstAmzE3wJ5S7ij8nmFqka3D0Sk4tLfsqblYmIOVGmE=; b=6r0ULQmuOR2pGjQkGaq+X0zZZJvhctJ9xAhbaN6VIqWReQJn4JxHXYL/oav5+B/NDQ2e5Z I1rRliOVm6onlvlWQzEImd15Qn4APpD0NKcWv3gx5aL+jJA7EKQP98Zv6DmnwxiN5SI7jK 8eFkwKDSMQkMt2UkeGOKbx7/63Vy++Q= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=ltstESWrI/s3Uqo+zvpVMyNbwD0Kg9tFqNwnF8piooX/o3rH3zy0YwMzoPOPGmikguDk//xoUD/R8J+6X0lBr1ScqgPKAKe4aQ6ohHVCSweuUHNapZRP420BuH2l6NyaCmJvYFeY6i9y7d68flZYptxMWyenpS+XBl4a58Y6WkCfPyIWrxUxdvbHRuNeie/XQhOn4XqIDHbVRy8yDPENZbhsQmFImI19OV+e9HIe7adqtlc1u4SMkajcCfTPTXajdr8oXKSgFPGkCubAx8vqd4tW2B+cxDRrAwmgRldSRtuKGPK1VAKbv0ZH8XYKQU2fcNnUaiq8bbDXTVi5YS45/g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; 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=dstAmzE3wJ5S7ij8nmFqka3D0Sk4tLfsqblYmIOVGmE=; b=N4gHYiCI0cfs+S0erX85WCI+9fW2ZfF7A0kud3RJoIGHo1vi+FCW/UsaMjyy5At+CHOlH8ohRc1iMB2d1C5PslwTB+H9mHEAOg1/btzNLtaUIWYSPq1hrexCkiDOxhU8UnUvxyTXxyay/qFkjlGdoEYKvRiKCqpxmCTKVlCpgIgU0n7XVSUMbkDH1bFzDNeZ6F1/V1ND2SiG82iSf3VqDLwiOqgABiCZjvdW07bmuu4qdoxkIwNkAKO2w3JwsalSl/BXQNFIEclW86RkTAcdqveaKXkTyES+PZGXiJBFfS9lgvvdaWBJanZvNfOo1qjk5C1nIiJhgdKrOSNgkKbLMw== 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=dstAmzE3wJ5S7ij8nmFqka3D0Sk4tLfsqblYmIOVGmE=; b=tjwGuzPFP6yeGGpYkCTr17OPr1zO403ptQn2p/H7AV5uVVrdHI386G5DtQIZ099Rw20t/YVtTHvA6bz5XklxzZOf4Oz+AU6jwXqIitlvdu151h86Z4rQHao99v+KB5N1PR71lNkT3xXgZBsxaO+UuwRfi7dhtzqnZrrRlkcWIVk+729yC+eJu2YUAXtc7s0MJHDX5c59smPT2tvAH7aKd8rqYyKqf5K2nPRxhA3tpMVxDab9mvNjgVeXRDo67DYIabM01A5dKDI3j/VNOJ57Ve9LNGOrIPGN6WA1q+gOGF3WyGpxfAfTPhQknYJx/chnhidfO9xaKp6NSJ+W8Za/rw== Received: from SA1PR12MB7199.namprd12.prod.outlook.com (2603:10b6:806:2bc::21) by PH7PR12MB5686.namprd12.prod.outlook.com (2603:10b6:510:13d::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8655.34; Mon, 21 Apr 2025 16:03:55 +0000 Received: from SA1PR12MB7199.namprd12.prod.outlook.com ([fe80::ae1b:d89a:dfb6:37c2]) by SA1PR12MB7199.namprd12.prod.outlook.com ([fe80::ae1b:d89a:dfb6:37c2%7]) with mapi id 15.20.8655.033; Mon, 21 Apr 2025 16:03:54 +0000 From: Ankit Agrawal To: Sean Christopherson , Jason Gunthorpe CC: Marc Zyngier , Catalin Marinas , Oliver Upton , "joey.gouly@arm.com" , "suzuki.poulose@arm.com" , "yuzenghui@huawei.com" , "will@kernel.org" , "ryan.roberts@arm.com" , "shahuang@redhat.com" , "lpieralisi@kernel.org" , "david@redhat.com" , Aniket Agashe , Neo Jia , Kirti Wankhede , "Tarun Gupta (SW-GPU)" , Vikram Sethi , Andy Currid , Alistair Popple , John Hubbard , Dan Williams , Zhi Wang , Matt Ochs , Uday Dhoke , Dheeraj Nigam , Krishnakant Jaju , "alex.williamson@redhat.com" , "sebastianene@google.com" , "coltonlewis@google.com" , "kevin.tian@intel.com" , "yi.l.liu@intel.com" , "ardb@kernel.org" , "akpm@linux-foundation.org" , "gshan@redhat.com" , "linux-mm@kvack.org" , "ddutile@redhat.com" , "tabba@google.com" , "qperret@google.com" , "kvmarm@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v3 1/1] KVM: arm64: Allow cacheable stage 2 mapping using VMA flags Thread-Topic: [PATCH v3 1/1] KVM: arm64: Allow cacheable stage 2 mapping using VMA flags Thread-Index: AQHbkaduhEbbxySPq0WwO4LU4q6wXLNsQygAgAD/GeCAAIkeAIAAC14ggAFVjACAATjx0YAGtS0AgACvDoCAAOaHAIAANr+AgABucICAAD0IgIAAg/iAgACoeYCAABKYAIAAFAsAgAAouYCACiALVIAAbFcAgAANkACAAAgBgIAAHy6AgAAGMwCAB6GYgIALBt6AgAAPgwCAAAfeAIANn5WYgAhUlXQ= Date: Mon, 21 Apr 2025 16:03:54 +0000 Message-ID: References: <86y0wrlrxt.wl-maz@kernel.org> <86wmcbllg2.wl-maz@kernel.org> <20250331145643.GF10839@nvidia.com> <20250407161540.GG1557073@nvidia.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: msip_labels: x-ms-publictraffictype: Email x-ms-traffictypediagnostic: SA1PR12MB7199:EE_|PH7PR12MB5686:EE_ x-ms-office365-filtering-correlation-id: 8b241cce-906c-452b-93be-08dd80ee1dad x-ms-exchange-senderadcheck: 1 x-ms-exchange-antispam-relay: 0 x-microsoft-antispam: BCL:0;ARA:13230040|7416014|376014|366016|1800799024|38070700018; x-microsoft-antispam-message-info: =?iso-8859-1?Q?KucMiuuBXw/O50VG2IlxHe/3iU+CgRFr0JV2EZzfU5u4jz8fDj/ZTegHXc?= =?iso-8859-1?Q?hRyKw5kbLHIbagQrjVFeh9fihq34oWx9NCdARz8KQlEKzInYphA8tSEGqO?= =?iso-8859-1?Q?XNGkGFg3Rm0bEot2vHtzOZz0EC4K1Y1r5UU/RqJ3D+WH283SZoVHc0L0Lx?= =?iso-8859-1?Q?Tv4VjEwKYsiuGZL7cs0wJD+n7JFUUv3vIOCRlGW2JDpWldw0iZWkLTE07w?= =?iso-8859-1?Q?WfnOy4xTnu6WCPPNEwJ7pvro9Z5tzTu3hzQMlpgZAnPyiXgVV7UXL/Ycym?= =?iso-8859-1?Q?IKbNw+8kk6kJp6YxXAPMZd/FM13GiFgv8Sgqs6tqlUFGCbk9wFWV/17Dwy?= =?iso-8859-1?Q?ZkZk5l6/OLDMUJCgzJ/BMtpicqsbNP7jh53PUBuuFk/7t+UECdhwT1ZpAH?= =?iso-8859-1?Q?TCoLDJFTFs/6MGN1Ao19KPrdv7zR1I0HqbOXSlp+lba/xjEmlKd8IZAgBm?= =?iso-8859-1?Q?K7bSfVm3lHBcesprJpcYtaKxjQ0dIj5WND2Cz6xx3BLgUpXiHealB8U9OF?= =?iso-8859-1?Q?RGmPnQraUCEsvDbtDF1gziuFIpzLCT/s2VQZfUaRQ7OkdvKVInBTinrDHV?= =?iso-8859-1?Q?aFLQ3zFlmRlhm2FI78STzBWCsyOCMPNpJs/NywjMiSKfSDvJ0WoZkUybe8?= =?iso-8859-1?Q?1c36VLyradxtgZ2G6w7hZtiq9EnxVPtxlcD9y3FOxWA8mJDxAp4HC5jDnw?= =?iso-8859-1?Q?nthwqDGKaPHykVxxE/u1jR6Sx/xfv4U9Vcb7wbUJfnmr6KMjJ1egU9CoF4?= =?iso-8859-1?Q?eoZBpIBaGv8hG07aFw0d2QQ68W6hsu5aRsimVMRagprxfFsF16WKVUj6mu?= =?iso-8859-1?Q?3t9AR7Ohcdsv7i3e1pxwzNY7a3w5Zr5g2BKxq6a9PPcW3H8gvWYiHLwusV?= =?iso-8859-1?Q?qgfvo5uL9EG2EACqyr+k+zYQ/ECZ82dTB2dgVksODtXdawBZmXgovdVdAj?= =?iso-8859-1?Q?DJaldWetBv7u4yXdeyc2jgMw61GYEGeyENfh/XG0435ogOz46vpkBlIFwy?= =?iso-8859-1?Q?a5yeG13qM/5f+Qlnrmx4fzc3cad5xmXnNLaYhzdZ/jRzD26kgD/HnPw5s2?= =?iso-8859-1?Q?tzgM5WgnOtndeeXgwBmoFTBDWdvD8OoVelXZctOwNnEGSJMrNVq1V7C5mM?= =?iso-8859-1?Q?LlW9LM2QQXA9vmC7P/V8RFzseN+rk+79JitnnBmqsn5Mi8CJITmC73GpOC?= =?iso-8859-1?Q?EDYMlaKMsRgKsm+SqBkXoERpLt8F2BTOlCHWMxc2D+Kjq2htz3EUmebNx9?= =?iso-8859-1?Q?jGohuAoo3qPCtGFwE3WFcR7c1tG50cREPXJ+pAcYJhl+e2OCWiVGOLD+/z?= =?iso-8859-1?Q?H1b36zmQy78q6K5VGxxarexMJRze93xC+Tg8FWDOUdC7QL73GiSM9ljMWm?= =?iso-8859-1?Q?0HtQxojMRK/uXzsZOdCGGX+v6XWCJH/FNXRH+1lIqvoXJZsoq/YNJqyjc6?= =?iso-8859-1?Q?OFZ6IM/4Df9Cyu/CS+3atJv93hfM+ZojezCBDbzSxs78wn55INiqcEExIE?= =?iso-8859-1?Q?gv97EpPTVtEtf/jJyJPkckHL53V4ypqfrRQ5vqishrrg=3D=3D?= x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SA1PR12MB7199.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(366016)(1800799024)(38070700018);DIR:OUT;SFP:1101; x-ms-exchange-antispam-messagedata-chunkcount: 1 x-ms-exchange-antispam-messagedata-0: =?iso-8859-1?Q?oYhdRqtYy2ttO4vPLLAitzNMY59u2dUeFlomGCbT8Z5AyykCIL6pIrqKqL?= =?iso-8859-1?Q?KuPKYUmYvfJfBYeIIVIPnnStzSslcAYiu089YxO3AEUJF7qYdlJdNWFl6Q?= =?iso-8859-1?Q?g80HePVt4sKkmliTRabmlaBRsyHyogvViYuNn+aU65BDowOvxHYhXH2I/j?= =?iso-8859-1?Q?v4YaG4kBJudwrQkK0LfE7p7auUe1+lYD21pL1QAooZ71msypMu5LNJR9AC?= =?iso-8859-1?Q?KBdfZWX95hqR3mgvllp3G8xE2yH2u+29IZU5kraDzfXhB/fxeOdcYdzk6V?= =?iso-8859-1?Q?tRVCKhImH2vmWh13gTJUtZe5/EtuohOc0b6Zgv/p3mlUM3UgMMlkxEVZWk?= =?iso-8859-1?Q?SNNLR6NYV7CrBMb6HWUqG9WqmPHpPePzhjZgxL2XHr6dWZVaxajm9iEhGv?= =?iso-8859-1?Q?RngSHHmpEm1kVQ9wTHTm9pG3eP9edsf0+ycmhiQMbDdcxSRVt1jVKvIVgS?= =?iso-8859-1?Q?VWijnZBDXLUQ8EeS58d+fQJUWVj+y/Ho9CyEvB0siy+QiXCSDNk0K7ecRu?= =?iso-8859-1?Q?H+sdN7vAR5Sz8qTNfFJ+3GQDb2aHGw7pMrQ77ZkA8nQDYaEKKCScaVk6f4?= =?iso-8859-1?Q?MLn6QeL61BnttICfYEkXMVatoYChIjJisgyJTw81rm9nIvUVZAdEgSveta?= =?iso-8859-1?Q?3EXVCsf1JEm3HbxNQXXXpVPRYmlbgjTpIzrXrnAUBchHIliLpwvTLJPUv4?= =?iso-8859-1?Q?gUzJw7XSfvgU/ACSqIg3l7JOoEQPT1srW5Ov+75huw2OiyA7BvLPlJ+OlT?= =?iso-8859-1?Q?/2KrSIAjh9GnjLDQKKrBMA15CV+KdFYBqnNI4+LsLqiv4bnMFjNYNmbHs6?= =?iso-8859-1?Q?als0vFhtbOb1udQ5eADOV941nRrZL2jE1IMS5XxqLunldkSl1DP9Wxh//y?= =?iso-8859-1?Q?cwfsLbTXB6GRWL1IAyhLdIhhiKRrbdPhu0t22SCWwC4Cdao0D0qN7Y6R0d?= =?iso-8859-1?Q?t2BA/jkl/JtF0nuQgLFUE3KXi3xyqqYt9Nr24uIoWmb0oVRTfzmxHfFLxh?= =?iso-8859-1?Q?bJObg6EAuvD9btvMQVFYsA+kKGphTQBjOAH9ULmF787I70jqLHvnXBSHT4?= =?iso-8859-1?Q?wXISupH3XAmMIO7CZYfosCeL6YFDLRSbtQATkE9ak5fFd5VDrL75Hu6KXs?= =?iso-8859-1?Q?UEEnkKMY1Y87b8ZVNjv9mV/zzvhg4F13C/JfSSXmBOk4ZzKHXuD9KWddrI?= =?iso-8859-1?Q?Ok4VH2+LvAEedUt90M/dEZG0tGc+TFs7ZyhB2QpiO6FcIdP5ZsX3nmHa5K?= =?iso-8859-1?Q?kcAsP8PctKoSRjIwFiGr00fiEN6VgTFPUjsUlX3vd2IMO9Wzj+tLs50+uc?= =?iso-8859-1?Q?KTi8ZjDaF86OCNCh1ZAKIpGh4RaxnafkqhFpyJVl3gYKaipMYNhH/fT5jf?= =?iso-8859-1?Q?kwv/vNyWY5xYBNJlhhOB4toNye+1d8HRb9YPP8JDOFhGjTVnlvTjCg3udh?= =?iso-8859-1?Q?oLZJ2o2gUR7cNhCV585SCF7QoXFjE8PDU/zTaS2vBVUphhmNlLsOJcZu8h?= =?iso-8859-1?Q?PS2wc2MuteRgC2GWvCYDz4J+WGmuSYgsiYxGFIlvULO3XM6bt/tTUAeC6K?= =?iso-8859-1?Q?YA1IwelC3UM/xq/A33s0qToNlJWMsW0lzW+pJWY7DpvDjWAX/GUFPM1/D1?= =?iso-8859-1?Q?Ug8mHD1CPdbww=3D?= Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: SA1PR12MB7199.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8b241cce-906c-452b-93be-08dd80ee1dad X-MS-Exchange-CrossTenant-originalarrivaltime: 21 Apr 2025 16:03:54.4462 (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: lC1+I7AiYryS8CUOGEvDFlu8KCQxLkpOZqg3nkRm0DNnLKZ961Hiyd0mDoRAFxn00g3cdB0f5irW2R2EqX5GXw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB5686 X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: B6AE7C0020 X-Stat-Signature: 31cdxbkpxkbsy8rxp3tfsb55wgb9puis X-Rspam-User: X-HE-Tag: 1745251439-183780 X-HE-Meta: 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 6QNsnBZP 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 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: > Hi, summarizing the discussion so far and outlining the next steps. The k= ey points=0A= > are as follows:=0A= >=0A= > 1. KVM cap to expose whether the kernel supports mapping cacheable PFNMAP= :=0A= > If the host doesn't have FWB, then the capability doesn't exist. Jason, O= liver, Caitlin=0A= > and Sean points that this may not be required as userspace do not have=0A= > much choice anyways. KVM has to follow the PTEs and userspace cannot ask= =0A= > for something different. However, Marc points that enumerating FWB suppor= t=0A= > would allow userspace to discover the support and prevent live-migration= =0A= > across FWB and non-FWB hosts. Jason suggested that this may still be fine= as=0A= > we have already built in VFIO side protection where a live migration can = be=0A= > attempted and then fail because of late-detected HW incompatibilities.=0A= >=0A= > 2. New memslot flag that VMM passes at memslot registration:=0A= > Discussion point that this is not necessary and KVM should just follow th= e=0A= > VMA pgprot.=0A= >=0A= > 3. Fallback path handling for PFNMAP when the FWB is not set:=0A= > Discussion points that there shouldn't be any fallback path and the memsl= ot=0A= > should just fail. i.e. KVM should not allow degrading cachable to non-cac= hable=0A= > when it can't do flushing. This is to prevent the potential security issu= e=0A= > pointed by Jason (S1 cacheable, S2 noncacheable).=0A= >=0A= > So AIU, the next step is to send out the updated series with the followin= g patches:=0A= > 1. Block cacheable PFN map in memslot creation (kvm_arch_prepare_memory_r= egion)=0A= > and during fault handling (user_mem_abort()).=0A= >=0A= > 2. Enable support for cacheable PFN maps if S2FWB is enabled by following= =0A= > the vma pgprot (this patch).=0A= >=0A= > 3. Add and expose the new KVM cap to expose cacheable PFNMAP (set to fals= e=0A= > for !FWB), pending maintainers' feedback on the necessity of this capabil= ity.=0A= =0A= Hi, just a humble reminder to take a look at the summary and next steps.=0A= =0A= Marc, will you be able to confirm if you still think we should have the=0A= "cacheable PFNMAP" KVM cap?=0A= =0A= If yes, I'll send out the series inclusive of that.=0A= =0A= > Please let me know if there are any inaccuracies.=0A= >=0A= > Thanks=0A= > Ankit Agrawal=0A=