From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM12-BN8-obe.outbound.protection.outlook.com (mail-bn8nam12on2068.outbound.protection.outlook.com [40.107.237.68]) (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 585343093B5 for ; Fri, 4 Jul 2025 13:44:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.237.68 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751636662; cv=fail; b=Deko+qqT9EvXScLlhjNaUEch6ggn4WrsV9N1rqGZDHcxuy1j6Oxu0x1DqENH0fhuAeA6471CIm4GS/amuK3eEJxs0SoNmIVTSiwHPFm0M8XU1eyDIrkvrbz18UmMF1m27y4FTkvzW3aMjVjv6BrVSDQsIsB2QpSHn7WOU4xIHy0= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751636662; c=relaxed/simple; bh=q6w88E9rbvlldZBNW02HMx07xHzwhYRqLD7TtGCAPXk=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=SFkNit0GQLGOTmdC4Mc5Fo9ikN9OpSo63Ao4GFbU2QkgNDh5nNi6WZgdSpdNv6LrsstjNnYM8U3ZD+8kB+qRb6PuCBXdmQk0/KdU1Y88k2LNlMlxh8lz+D6u+8My710yhfyleC5t0tevJuz/PSqchHblx9lbDaHoL3H3+VAvbBE= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=XOUivJ4t; arc=fail smtp.client-ip=40.107.237.68 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="XOUivJ4t" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=lbR2h1IzWXzKHLHmKoRpO2e2NQuQwy9VQFmjRk+yt8k52QhHlPVM4Vcdyn+eFp2/Lh9HNZXZgOTUJIpoauunYhNreanDJaFwdf8B8Hjeq9/XvTwMeFLC+UBoSu0X73OvOsqmQG/e/clPoC3TbIkHtAPQC9UUEdwnXKrkZlUHV9RttzkV80tIaLeGzuSxi29Q3GEpvAb0FJ9NFkoGDq2YcEGXMNTW8LaG6ttU381CihS/Qsx1N035zbO6pMY+up2iqM7mEeFpFLN/Xv71NxLDfv7W7VgWfzsHfrqnHjZUDFeJbmpp5q5n4gc5NxKeMC4eyhKlYEJG1BRD+UnPJkkvxg== 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=gKcMmFY3qGEscc0tTWWar2D2E6KDyROrrST7AGxmHPA=; b=GnkQcqBmKqIcPR65aXOilfc2AiyAjwxAOutoJFRt8n/2ULsekKNop6ygrBcmm+QjJ8CmToccjquHHoVJ0hUM74cjHQkdqta2qqlva8tqryRF5/mBFc7/hkKrThV9n/qX1BkH6ZpVUnDYLmi3p8lw2/NATpxrROxc8gnCb6KFUImAIeszgVb7fXekpNcRzomytW7M0G47bOjyJ+utmULX/h4ETIx4JW25tCqXY+I6BhiK0pvrrFeraYSTuE1bSSGcvvLadsjty/nGeIJlqiKEsK4+Z9DkfmajYMPtBLclPqGH/Rir8UUgt8DUO4n1x5j7K6uz+njJqYmRGnanUzwtRw== 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=gKcMmFY3qGEscc0tTWWar2D2E6KDyROrrST7AGxmHPA=; b=XOUivJ4td0H6yny8cYlDNPdxSDz9zNBjNNQ0t8Iv5vfdOnm/n9JtV9O7KqGjYGPBvZSYsl9S8+1CAUhje62hK1lKLdUC0mjBPAOeIIyFxINXLDYon0x+wzkuiOJmgKmbXfaskujiNpHllruVoLoA8ayCl6ZLhz9AXIjxqum1ULeQPod9ayYxKu8AWYw2osZrUYzFweBHh26cTvwGST1f8XSU5VFDk9qlaKLBQA2vmb9G5CPWTdbr4L76HU9ttOrcEg1JemI97cnuxKluX67jlx2uXFueW5QxWwzT9tI5cJX0bloJuY+50oCj7IaylWc3b7TzB3KUP+D3wJkJPvaVGA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from CH3PR12MB8659.namprd12.prod.outlook.com (2603:10b6:610:17c::13) by SJ5PPF183341E5B.namprd12.prod.outlook.com (2603:10b6:a0f:fc02::98c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8835.29; Fri, 4 Jul 2025 13:44:16 +0000 Received: from CH3PR12MB8659.namprd12.prod.outlook.com ([fe80::6eb6:7d37:7b4b:1732]) by CH3PR12MB8659.namprd12.prod.outlook.com ([fe80::6eb6:7d37:7b4b:1732%7]) with mapi id 15.20.8880.030; Fri, 4 Jul 2025 13:44:16 +0000 Date: Fri, 4 Jul 2025 10:44:13 -0300 From: Jason Gunthorpe To: ankita@nvidia.com Cc: maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, ryan.roberts@arm.com, shahuang@redhat.com, lpieralisi@kernel.org, david@redhat.com, ddutile@redhat.com, seanjc@google.com, aniketa@nvidia.com, cjia@nvidia.com, kwankhede@nvidia.com, kjaju@nvidia.com, targupta@nvidia.com, vsethi@nvidia.com, acurrid@nvidia.com, apopple@nvidia.com, jhubbard@nvidia.com, danw@nvidia.com, zhiw@nvidia.com, mochs@nvidia.com, udhoke@nvidia.com, dnigam@nvidia.com, 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, tabba@google.com, qperret@google.com, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, maobibo@loongson.cn Subject: Re: [PATCH v9 6/6] KVM: arm64: Expose new KVM cap for cacheable PFNMAP Message-ID: <20250704134413.GE1410929@nvidia.com> References: <20250621042111.3992-1-ankita@nvidia.com> <20250621042111.3992-7-ankita@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250621042111.3992-7-ankita@nvidia.com> X-ClientProxiedBy: BYAPR04CA0023.namprd04.prod.outlook.com (2603:10b6:a03:40::36) To CH3PR12MB8659.namprd12.prod.outlook.com (2603:10b6:610:17c::13) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR12MB8659:EE_|SJ5PPF183341E5B:EE_ X-MS-Office365-Filtering-Correlation-Id: 0297ad9a-662b-4032-4fac-08ddbb00de5e X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|7416014|376014|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?/rP4XHJPrkXF+r7bNwLsiPLMjrMJymBgYHnXeM0mTKSfsPT5zVJcnDVsXQ3B?= =?us-ascii?Q?ADrhmZd4VgaLHUyXNyFrP+18e8xpOlTLA5hqv+Ez7TY6sjLwGUhaTM3ViWlP?= =?us-ascii?Q?2pb4qvVBe7NP1nBFKRD8cDPbGIWzdwPPOe4y5+exIE2j8lFE/9t2yHvMCTkJ?= =?us-ascii?Q?aeysQM0sV0rjDraAiEGBFthgfrCFJsZNDrWS54i7gvzEZM0ro7HSHtHESAaG?= =?us-ascii?Q?etCvJk70+L0MA0934+KwuHQDTAnyoTusS3crA7RbGBPqAHJbX6HqWt/NydGn?= =?us-ascii?Q?4gqbNLowlvKmc+1zuGaDEkkPC1LAxh6iWWM1NuPJob9xvtcWtiHy6j0e90OG?= =?us-ascii?Q?zdYxHq7/+hHBUhzNrIjkZSRhPqAbWquvwlGhFBzFjL96xiY/dfoZ1FiKbXB3?= =?us-ascii?Q?NzB2fojfuJTaoC06vy+Igj50GneEpqMHh9TZXHXN5ypItxYZpiBwTXwYJW3z?= =?us-ascii?Q?Gwgnqx5LYSSO8Ojv5n0zvt9KCEzmFM9xhjxjS1007wts0mJVDt0fGPW18YRY?= =?us-ascii?Q?adr5MMIRmxnjjouGXvyC0WwWjyDOt+J3oLLaxEe/FBeaTDVFEo8fULVFZDcl?= =?us-ascii?Q?HZbYtTrIu5maZW8JxycxSBcVjehWpTTkq/wAQevQ7bspF7W9n+jz2VsTnSwB?= =?us-ascii?Q?JAldOw2r7GRaAIBLpZnBExFZ42Kolzq905hIFSsNjvLvaDfKopflae2L18cD?= =?us-ascii?Q?EvcDeXkk2m8bo6Zeu2sdLP0YTuO+kGHWBRcwgCDUgfEYlsNWNxQNuOqnUSXE?= =?us-ascii?Q?Y/UZhKGq4OrrtnkO5fhFSDKmB+DVbDKua2qtWYrGjlnMjC0ogig+mvPVPO8b?= =?us-ascii?Q?ypHZLRJ5lI9ZWoO1dJMz9eTodgZEjYkBJ4/ZMeKmRuh0vq9Q60bZF0xdqca1?= =?us-ascii?Q?9cpkOs1QICtenD3JbdszP09dVrG4Zz42G2DjDs7dqJXlwWI0yasql4coiBhT?= =?us-ascii?Q?+LfVu8jUyrrRkWfMpoDRp2i7QmjSFYcNvHsfC6He1O1wwtNgYCGCSwnT4tCp?= =?us-ascii?Q?FNwcXXQOr9meLqNZ3OO00BZCoZA6+t4sa3qJQKcPlRERcyrzRnlagZclUKHu?= =?us-ascii?Q?6wyu/2GMwqgFwz+R2sY83XRvM7sdCpkOR9nZ49az4uGE3MU2zSaJUGKMmq5O?= =?us-ascii?Q?5Hw7GH82xqKnklJhiKg4JYzqn/9wV8XHTag7I6L1XJbu9TCgkEieSRQglqXX?= =?us-ascii?Q?q5oLuj1caRILi+EvObff3SjAOfElosX/26xznENcjmClSPFsDIPna0gOQg++?= =?us-ascii?Q?lu/MZ0NMfCmzQmLHEG44DhmrzvD7sjewDF1jW2GbJ6qS15tVbo59FS98vuDj?= =?us-ascii?Q?I5YHWNUN2HayFZrqXGtv1E74fNj7REH/05tKBnh2O6y4Y0rCdjiDk4aQ0ZLi?= =?us-ascii?Q?LW1r+J/ry494m1aNoxNoONa/93C3Toeixx6G+Udb/+f9ZcQMtYmAlmd1v4hD?= =?us-ascii?Q?si47moQEC5s=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH3PR12MB8659.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(7416014)(376014)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?L853Snv91Wc7aiKEU/NNsmmTz63Ni6ifKL9C/pbKGwIjG5P6J51b+BMqapEx?= =?us-ascii?Q?byb0GpjB+XH0R4/fURVOaMlvCPf+OYl5qGAyuu9ZpvjnRLgrsIneX8OwYP8v?= =?us-ascii?Q?XPTpoiBgpcsVut2sRbEFCofRYu/ZQItsDYBs6sri1/Cd6SFpZ1fzXpWSV2dU?= =?us-ascii?Q?S7Hmzqre9nNBuwXOzsQfMh/eGWmNXjCiArz21uS/QiQ6A1rq8bdiFjwaI0l+?= =?us-ascii?Q?/smQNg//wABBXBH0txGuVOeUm9OiGuNP0t503/4YKwV5Gim9y05vSvVGNKV1?= =?us-ascii?Q?rL4JMfmG8V8rfM0gascOC98mBDscXFNtRZ/fhGwq74TLiyQuKa2H3O/1U2NX?= =?us-ascii?Q?EsRy1c2vIXxFpdOkDijFABaJd33E7NZjy789QQJRbchWdlM5aTewMzsOKaTc?= =?us-ascii?Q?DOrv+RplS16bTg+zKUC6gtuyOm3Fz6yBImiVeCXeQ3Sda4sgaHJtIuhsBEbY?= =?us-ascii?Q?JWSFsoWhxDlW5vbGmdxfMBwoXBx6qBU/v48QKHb+9Frf7jABbrmRQpbd8X5i?= =?us-ascii?Q?J+ZmvKhdOLJMYURL24MyRHMGQUjDIZ+InZg4NvjleKhkTtgNrwh4zV8fIsMz?= =?us-ascii?Q?m/joQp8waGAUwSnKk0GKBr3KRs1sc3Lgh0KD5ohpV3OxlqlzlrBZ0hz96ZLZ?= =?us-ascii?Q?nn88t6doVbiN7vLfz7g1gyNG2zhHGOchgXnI6bRAuVGln4x2rEIFt4nH8R3i?= =?us-ascii?Q?+YdbqSofDJiMnyQNDBSerLt9HTlbAG54BpotiqetrUP0uZbGRhMVpc4paM78?= =?us-ascii?Q?GDNEPe6a823JMa+rUZCu6CHFlTrxw9fsk876ynwTMjc2B2rRZq9oHVpztzAQ?= =?us-ascii?Q?wmbMLD+3cFxrLpkmxFe8FbAfOZywROzBd4F6Kipn4j3g84HenBFdLyP25qlR?= =?us-ascii?Q?HLD1lMpiGGAcQxbExs0+fVXczhtE/caf6UH13vY9AONHhko/hd7PHkMmuQmS?= =?us-ascii?Q?tbmFtzBriuQV3nQEHpa99/tnQppFJpNa9RhTFjbyNperZjGnN+J8s+rgMVF3?= =?us-ascii?Q?fcr8+7SEBVuP8xBDwb5nocT8wXAsRQcttOK7Vpv5F868nPjQtW5U0wztWjIh?= =?us-ascii?Q?atln9Ht9E9Mm/7tChnbq4aCC/JVfzZ99O1qWApKgiayiw9ZGHLRfGpWcyAc7?= =?us-ascii?Q?w7ZlHO+HXftAKZU/kC0TNHZ7PpXe2zDNNF4TxyK0uyoFRRCayXNnUesIZwv+?= =?us-ascii?Q?LMhBRp0j/KArm1lgI5OUORFwmPYlreRbEEPliRaZweWiuU/OHSzDV7GsM/9O?= =?us-ascii?Q?cJ4dMwoKcR9E0OMlw7Mb08efGoN5EyMN4leZJnW5P1ffXD1qTjGwb7izRPW/?= =?us-ascii?Q?d2C2ciNlFKmFo6J4L6cqGlweazn0oyn6K51WD6WWw2/3K5a4ZXr4ptjn3r8q?= =?us-ascii?Q?c9VlhmaORiXS4+ATsIOOCUduJS9zIX25lby2IkzJUBh1BFWN6QG+UXvaWyJx?= =?us-ascii?Q?BRjnsrVmIEkBlvkQOC2LvSWEWfcdhMY1iuSfPzuADdL23Qpz+tHkRpzdzN/I?= =?us-ascii?Q?2tyOdzlKgHEAf3k08G8xgt0blFt2RInUlNAnTQ9xgghoLSBgB+ADJBFDbk/C?= =?us-ascii?Q?noMyprmCYa8vrLWV8ijgPwfEAplh4uflvGtxFhIJ?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 0297ad9a-662b-4032-4fac-08ddbb00de5e X-MS-Exchange-CrossTenant-AuthSource: CH3PR12MB8659.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Jul 2025 13:44:16.5663 (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: Gtio6CCj2Lfjq/RL46R4tl/7G+ifeazbwdKDJaCLuMssJtZHnCZxNmmehHEeRlUi X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ5PPF183341E5B On Sat, Jun 21, 2025 at 04:21:11AM +0000, ankita@nvidia.com wrote: > From: Ankit Agrawal > > Introduce a new KVM capability to expose to the userspace whether > cacheable mapping of PFNMAP is supported. > > The ability to safely do the cacheable mapping of PFNMAP is contingent > on S2FWB and ARM64_HAS_CACHE_DIC. S2FWB allows KVM to avoid flushing > the D cache, ARM64_HAS_CACHE_DIC allows KVM to avoid flushing the icache > and turns icache_inval_pou() into a NOP. The cap would be false if > those requirements are missing and is checked by making use of > kvm_arch_supports_cacheable_pfnmap. > > This capability would allow userspace to discover the support. > It could for instance be used by userspace to prevent live-migration > across FWB and non-FWB hosts. > > CC: Catalin Marinas > CC: Jason Gunthorpe > CC: Oliver Upton > CC: David Hildenbrand > Suggested-by: Marc Zyngier > Signed-off-by: Ankit Agrawal > --- > Documentation/virt/kvm/api.rst | 13 ++++++++++++- > arch/arm64/kvm/arm.c | 7 +++++++ > include/uapi/linux/kvm.h | 1 + > 3 files changed, 20 insertions(+), 1 deletion(-) I don't know if any VMM will ever use this, but it looks OK Reviewed-by: Jason Gunthorpe Jason