From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from PH0PR06CU001.outbound.protection.outlook.com (mail-westus3azon11011009.outbound.protection.outlook.com [40.107.208.9]) (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 8F8E233064C for ; Wed, 18 Feb 2026 17:03:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.208.9 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771434207; cv=fail; b=EcbxawMKUMTiRASY92fRWawWQ9pCT45d4knvJOkJuF7BrfOKzzGHGPmSPyK7W76u/l+0BQWjIIKHSAfeR0W9Dq9WgZFVcufK/LFDHMurN/7oDoUc/PylvrgnMb39TjtEf8TEQ6eRX/FPw19dKNc09ahqUqiLj5gLIEClJfGwVXM= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771434207; c=relaxed/simple; bh=eVCXPxnd2LWKo2Dv3uYSsMSH9IXqz4LmmtNlnPmrOAE=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=k3a8S0HZjFBXrZ6/5/Um4mCYG/Mok2OmuGPoY5Pz+/8MSE50UYN4R4Rr2nF5/D9JlPUPwe+KuvEFeknjNvAXiX/njYjMWZAAYD0pvaJudJEhHNG864Ckw5PpEdlA4Pu8SA3jVlMkR0z1yOcfJm+5NKqekdqB27V5IOLVvBl0vQA= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=gM+W16Zm; arc=fail smtp.client-ip=40.107.208.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="gM+W16Zm" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=n6JI+HTs9OHv51PrAEr33XiRLrVwXe1uoq2GK1BnvM83PzgaCp2QhXkpDywjfVTb0KShOMQ8DCa+t5aWS61A+R07qUSpm2gEKDajpz5HWcRfxcTyvuPyz8hFB8JM0thag4xBgVM7jZn2B6/1tuXiDADSiSbLK3tKnCE6oIPCu5jX1QAj3tGDsfpual9xXLvBRVZ4EoUivns/MRtTeqXY3o0IgubAvrAPyBvcteVUigBIactg7cwq1ql+cTVHJb7iquQ7Cor4WsJ0KgxBMbEhlBVNq5izaXOEwZlAAH6gzsBYQyl8WqRJkRUCWo4lwJh94kQa8Tc5eHd8YXJDRAyuYw== 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=qFadgdCew5O9OcA8rvcLAuoynsrNi1yLbzWdE+VyIeA=; b=QLfIyzE6DJy2+Z9h1061h2lQ792OarmcdT7l+nU+hnh1B5/tMOiw7wm/a1Yc3QQChpdg5IybSPO6hi5hErjyVULUgcRpKw/s9ciADVist8zQHgjpCTECT1iE/lgn9hpvb2B8QjHGHmW7cM0j9UBt8G4NA7+TpB1XzWPb6Etshx6mRJkSBO1NFxcVoSPulejYhr639CSeumtmo2djk+pYZ/0BUjqJDfC9gJ9dfU0ZAHDOCxr9xGjZ3wdLsww4BY7rkk+i2Wvi3cC16uIuvhFpHi/xqlGvDd/WSiVM9HzmS1zE3Xmb/OIhMg7ez0Xpw4aJkrm08wI4zCuBPQnKjyQxZg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=qFadgdCew5O9OcA8rvcLAuoynsrNi1yLbzWdE+VyIeA=; b=gM+W16ZmLIndgft0NbyERnZvS/VARvypYzQU5J7B9nbqe8fsP/jKFJtx6MxJ3jQYUZs2CHcA9O8gGrJyRF7osdHmyevJYOlVwgrdWyHC8rOAmzJ6/Xo+Q3bvwcw1VFkiShpuxKs3I5rcCedojyr3BAV09FlY+IODp3so10+t0EE= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from PH7PR12MB9066.namprd12.prod.outlook.com (2603:10b6:510:1f6::5) by DS0PR12MB6557.namprd12.prod.outlook.com (2603:10b6:8:d3::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9632.14; Wed, 18 Feb 2026 17:03:18 +0000 Received: from PH7PR12MB9066.namprd12.prod.outlook.com ([fe80::f71e:4264:146c:b356]) by PH7PR12MB9066.namprd12.prod.outlook.com ([fe80::f71e:4264:146c:b356%6]) with mapi id 15.20.9632.010; Wed, 18 Feb 2026 17:03:18 +0000 Message-ID: Date: Wed, 18 Feb 2026 11:03:14 -0600 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/6] Add RMPOPT support. To: Dave Hansen , tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, seanjc@google.com, peterz@infradead.org, thomas.lendacky@amd.com, herbert@gondor.apana.org.au, davem@davemloft.net, ardb@kernel.org Cc: pbonzini@redhat.com, aik@amd.com, Michael.Roth@amd.com, KPrateek.Nayak@amd.com, Tycho.Andersen@amd.com, Nathan.Fontenot@amd.com, jackyli@google.com, pgonda@google.com, rientjes@google.com, jacobhxu@google.com, xin@zytor.com, pawan.kumar.gupta@linux.intel.com, babu.moger@amd.com, dyoung@redhat.com, nikunj@amd.com, john.allen@amd.com, darwi@linutronix.de, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev References: <9c77e206-442d-4891-bb29-295bc8bffe20@intel.com> <65986f9e-59e8-4f1c-aaa7-1edf45af24d8@amd.com> <31b42ba3-dd0c-42e7-ad1e-800c5cd2bcf8@intel.com> Content-Language: en-US From: "Kalra, Ashish" In-Reply-To: <31b42ba3-dd0c-42e7-ad1e-800c5cd2bcf8@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: SA9PR10CA0017.namprd10.prod.outlook.com (2603:10b6:806:a7::22) To PH7PR12MB9066.namprd12.prod.outlook.com (2603:10b6:510:1f6::5) Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB9066:EE_|DS0PR12MB6557:EE_ X-MS-Office365-Filtering-Correlation-Id: 7458e8a8-2b6c-4596-f9e9-08de6f0f9cf7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|7416014|376014|921020; X-Microsoft-Antispam-Message-Info: =?utf-8?B?T0hkQjFyVXpCeDZUd0FMZGdCY0xkL2dKQVBWSXpUYjF3MTViaEQySCsxZ0JO?= =?utf-8?B?Uy9qUVUzTUNSdWY2UXBBMG5CZnZaWnFIV2JuTDYvc3lQM0x6Vmk4UkZxRUFI?= =?utf-8?B?NTNhRWFTb3ZQT3RzdzhsM3NZeU9EVE9VRW9KclNnK2hXbVNEczFGUTZNcDRW?= =?utf-8?B?a0FKMkZMTWMxajJlMTdvZlhNQlNsNTNseFkyYWFqaXRpZktOMEdJMzg3K1Za?= =?utf-8?B?a3FyWFVxV3FkZDhIY21EemR0S1JjL2Z6YW5GdEVYcEF3QkFPRjJrWW1yRTNm?= =?utf-8?B?Z2NCTUdhdkM2T1JQYVRKeDFxSzMrYlRUR3R5OEFEVncyV1lXWUZDKzhMdzVB?= =?utf-8?B?c3V6SHNQUW9mSEFCK0hKZnFGR3pySmFaWi9nZGtwNXZUblpkbVVlNDAvV0Uz?= =?utf-8?B?bklrQXBDRlB6ZzZSajErQmZ1TURBa1ByMUQ3alRSZUgzVnJoc0ZIN0g5UXRm?= =?utf-8?B?QTd5UCsxRHFtYU5Jekd1MUtJc0tTTVp5ZUh4c0sxeER0bWRsWmtIdnVRaXMw?= =?utf-8?B?eFlISUgvRmE4R2Vrc09lUWRuTjZmVk16OXVaakNrRk91K1R6Y3llY2UrM0Yw?= =?utf-8?B?N0Z0MVBIOExzTUxUd25aSEYrWGo5U3VxcWZUT1YvWmltV04rRGF3eU52RkVC?= =?utf-8?B?ZUlQOG9uUjVKU1RRRGN5R0VSQmlqMGhzR1ZUZWQybTM4eXorOHZzRlZwbHY2?= =?utf-8?B?UWp2MmFBSnUvMlJDK0lUUnVHR0ZnaXJyNW1keFlxTDdueHFPRS9SRVNHVjk3?= =?utf-8?B?NUtmOEtEa0w2NkZMMTJqdnFuQXllcUJaYzQ4dXdFZmdrYXlYc01FSmlJOFhJ?= =?utf-8?B?VEROYU9VQlhpRTlUR3R5STdGNjVnbUNjaFhvQXdjVWtEUVloajRyVFB1TGlr?= =?utf-8?B?SUwzRXpLOHlLVmhzd1ZYbUNTaksxTEFWMHk2bnpoczA0WEF3SUxtZlZzRGkv?= =?utf-8?B?T1BLT1dBaDhwTThrZWs0S2VFSURtYUhDN0phNElSRkFnQnhKQ1BxYWV1bE1h?= =?utf-8?B?YVdzU1RNR1pLNmdBbC9NSTZHY21Wa25uRUtHVEcyYkM2Wk96cU84a09Xa3pV?= =?utf-8?B?OFV2dHVsU1ZUbGsvWkN6ZzRjeGpjSEFpcFFRQytFNnNXTmpDbW5VSjVFK0dk?= =?utf-8?B?L2JsMVVqOXpOamxHMGpOL1VYQkQ0VEQyd0dKaFFqUm5pM3VPU3djTlZudmJj?= =?utf-8?B?SFhNR3pDSlA5ckx6aTE0MzBNcXBPZlRWaDJIL2U5Wk9HWnEvKzB1YnRrVkF6?= =?utf-8?B?OEVXNlZiUzJLTU5SeVVON1Z5SnNtZGNwYUhlU3ZYeWJ0amRPVnZKbmRNbnpu?= =?utf-8?B?MXJuRTlsc1dnRHIrbEdWUktyRDNCS2FibDlhdWpiWG1YcVNzaEYzS2I5OHNL?= =?utf-8?B?YWtGZDlUVTRQclFyUm5mOVpxUXlCQmN5Zlh5SUNFbE5IbGVsekxjMVJKU3BS?= =?utf-8?B?Y09mazlzRi8wbnlQR3hzYy8vK0NTTTZHQjM2cmU5VC9iR3RTSUx0bkRac051?= =?utf-8?B?YTViV3VxTWkybmplZ3liSXZuK2l1M2JaczRuMHNiTzNTMFljYXpiUWVhVzlQ?= =?utf-8?B?NFdTR1pQR1N4UWNML2FxVUhaRnFDc05LVUdONG5HT3RLcXdxb1JkaXl5cS9N?= =?utf-8?B?WUZSYmozWGFnTDBrcVMvRjZPWllLV0t4dmYwL2hhNUNvWFM1WXl4K1BvYW5Q?= =?utf-8?B?U2lTWkFqeUNWSXczaEgxeDlWNTFyb000cHQ4SkVUVFlaaSswQU1vU3g2YzBR?= =?utf-8?B?M2FjU0JwcDZKVlJyUUNhWWpLallMNE1SMGNDMlNJeE9KOXB6MXFEY3dPd1JH?= =?utf-8?B?TGJEQXJXWCtFNm1sSGZvZFJEYnA3TVpFTmRvaWRPcEhNZWVIL28wbTVwdisz?= =?utf-8?B?U2hKVnBZeHdCdXQ1TCs0aDg5dTNYNnR6M3I0V1FjMStsOGtYaFpodGFQWmFX?= =?utf-8?B?eWVGckozZTVwTkxJTTVRZVJLNTFwaXhqYlg1U0lEK3dvbkdFd1BtSTBreE5o?= =?utf-8?B?L1FmWUFqczF6c3ljVUhIbnIzVjJ3YUh4Uy9pYlRURmI5QjAwZXJlUmlnZXVn?= =?utf-8?B?SWpFQ25WaVZSSFBKUklLdUdFeW1xVndWeEFEYVBucFo3VDduYXVRbExiM25V?= =?utf-8?B?Tmc2L25SV2xqb044TW9jbXhCSjR6MGZGQmxmYjRQSEpoRVIrdDkwRlllYmQw?= =?utf-8?B?aGc9PQ==?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH7PR12MB9066.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(7416014)(376014)(921020);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?TkxMbjhRRDFYV0doRndWVWpKMHBrTFJ2SmtMK0lLSDZSa0w5b3Jjc1BnSCs5?= =?utf-8?B?UGhMOTNwMnNmck1pSE1ZSW9YbkJldHNscVh5Z1JxMkhiU0c3aWRveVNzU0tD?= =?utf-8?B?QUZpRkswS25xZnYwR0RMSktGVkE5K0RNV2JBSFhCZU1wQm5ZQ3dmd2JzSDVN?= =?utf-8?B?azNITkZ5a25nRFkyOG9OZGRUNDVGWmlnUEpFeGtGM013ZFFDb0xaWlN1L0Z2?= =?utf-8?B?aHFKUHdEazFWNExjT3BIUzczM1NURnE1VFZDMUFOaEFuM3kxLytodFEwYkl4?= =?utf-8?B?T3NzSytIcTlpQUVWQitvb014anRHRk15bXk5VEU0ajBSeGhJRlNmWE9LZGwx?= =?utf-8?B?TkswNjBabndySHlHZDFpd2QrYW1hbUs1Z3ZEaER2N2NVdlRYMUxMdXdWMXky?= =?utf-8?B?WXpSS2RoalNtR0pNNnNHU3A0QWUxc1d4Mm1sRGpsaEtVYjVLUXVEdHlSdXM1?= =?utf-8?B?cXpBUm56Wk50N05LRUY3dzZ4VEF6MFFKY3Rob2RtRlJTaXNWMUJBWllqc01T?= =?utf-8?B?RjdoVVhhZ0R4d2U0NHcvck9UNU92dEc1U0d6YUJYUXpzdmhhMGtRV3ovZkZr?= =?utf-8?B?MUpicUFyRGpFM2N1UUE4anAvZ04zSWM3dlRyb3R4UHlBckZtUG9JbGNxbW1i?= =?utf-8?B?UWtBNlZrbGl5M0JBOURiZEtMcUV3eStENGpsT1duMFFNajJEZTFYaGJXSUMw?= =?utf-8?B?QWU5M0U3SEQwQ0ZnRlNyVFduYjBuWGFSS2RsVEhFZEZIU0VkMlNjMldyWnhH?= =?utf-8?B?dkRkU0Q1WmV0SjdVZWR0bEpSZC9KY1VlM3JnWTJDQUlSZWFjTkV0bFZQMVd1?= =?utf-8?B?QUpQaHdvL3Q0RXVGSjlvYWxtQUUzN3hna1gxSndhL3ZLTVpWa2hrbnpIMVJU?= =?utf-8?B?cjZZaWRtUkpIYTZHcC8vemZDQ0pWZ1BKeEVxK2M2K1JkMTl6TURvY281Zlcr?= =?utf-8?B?Rjh4WWdaVlIrbGsyMTFpMGlaK1FEU285N3AwU2VPLzdoK0MxaFdpbXJmdjJp?= =?utf-8?B?VGh2UTBkcTZCdEZhRnNXcEw1R1l6MmxCT21WYnJKZmhhNnIvNG9vOTFTZUMr?= =?utf-8?B?NVkwR0lTOVpDYlA0U2szZW45aEdCcUdDY0RzWGozYWhjL2NGS0dUTXNFYXow?= =?utf-8?B?UWpSWExKTmVvZjYrWmR4QnNlenczNkN0WS94THpwMm9JNGxUTVY5VVdHaGtt?= =?utf-8?B?ajBGdENxbTAxM1RjVHRrcjdkUFBOakMvZlV1dWU1MTU5MmZKbWVTYnZMdzh1?= =?utf-8?B?M0xsSEFybVo0NUpBTzg5dmFNS3o0ZVF5c29UdUUvYVQ4dVRJMVNtYWR3cGxB?= =?utf-8?B?TW1UZUJsSm1xdTc5WkF0R2pHL1QxNG5QRHJ0YmU5VGZ2VnZuN0laZ1Z0Y2lU?= =?utf-8?B?NUZkVFdPYURsNllCcDNZdmhSdGh1R0FXRElzc0FweUdicko1aWNnZnVrWHVi?= =?utf-8?B?ZHZEZmYxSG5COW1yWjNuR0JuUnFJQ3Q5ZXB4bHhxR0NRWDFqWmRjT1BSOXUy?= =?utf-8?B?Y2xWY0FHdGg3cXRXV21HMW1PRjEyS2lrRlpjRnBiY0U2T2tmNHNVSEVOUGZM?= =?utf-8?B?WFVnZ0JoN0c2dWFaL2pTdGIrTElwRVl6VzlhQytPRWtKdS9wRG9UZExFNFFV?= =?utf-8?B?c29QeFpkaXA0dlZBbkQvTnBPaG5rT2FFV3dEdUZtbmtvdTBScUdSakVsN2xC?= =?utf-8?B?ckFIeVRONkFCcEx1SXNiM0JmdG1mZm5tcU5ZUmk3YVpIeFpqaGlXUlZ1akxu?= =?utf-8?B?ZEpWbEJWWUpYRkVVcHRlRDdQTGp5UmpYdktIanYzU0k1dE1NdGNkMndSUGt1?= =?utf-8?B?N2NQU00wNHNqbXBVWDg5bXRpOUpzUkdNNThpancybjFFTnBFdmdTckYyeFE1?= =?utf-8?B?ZS9rSmU1NjV0RDhON011UUtlWnI0NW1saUU1MDNXaTRWdWs0QjdsbFNBTVo4?= =?utf-8?B?MVRicTJGQzE5ZTJoU2lDSlpyREdZbzRtR2RvRk9qODVNNTRhUVVlRFJvcjhs?= =?utf-8?B?ZDZBS0JOSy82QldSbU1DT1FQNUthSmVucEd3VVhjek1ZdC9MU241ODZ0aGFB?= =?utf-8?B?VzkyME80RW12bmwzbTdpdVBXdnRTT0xPRTl1K1IxQmFUR2o5elRhSDFqc01s?= =?utf-8?B?NVpTKzAxV3YvMExyQVdWWm5iTHlpR1Q4NkFjQWErSE04M2hQOElFcXBGRENU?= =?utf-8?B?WnY5WkNhN0JBWUI0UEtlRGxrb1JEamltZElkekxWdExDb3NzbkE0clJYTzNV?= =?utf-8?B?UTRqMVpvTThEZjJpZTRWdWtnYjY0bmVJNFBnYzNTcEtiSlZHVTQzd3d6Z0Q0?= =?utf-8?B?cjNRV0x3YmVhZEI2NGRaMDFrZmYxT0FpaFgwelp6dnk3Vko2dFQwQT09?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 7458e8a8-2b6c-4596-f9e9-08de6f0f9cf7 X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB9066.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Feb 2026 17:03:18.4292 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: CQqOIQ0jaYsr1K4koXfVdIXWIbON68a6Hp8HW40PkCfFLP4TL7LtRC4m+ozqLU6xwVZ9YZtPKeVUklpFtX0tCg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB6557 On 2/18/2026 9:03 AM, Dave Hansen wrote: > On 2/17/26 20:12, Kalra, Ashish wrote: >>> That's not awful. >>> >>> To be honest, though, I think this is misdesigned. Shouldn't the CPU >>> *boot* in a state where it is optimized? Why should software have to >>> tell it that coming out of reset, there is no SEV-SNP memory? >> When the CPU boots, the RMP checks are not done and therefore the CPU >> is booting in a state where it is optimized. >> >> The RMP checks are not enabled till SEV-SNP is enabled and SNP is enabled >> during kernel boot (as part of iommu_snp_enable() -> snp_rmptable_init()). >> >> Once SNP is enabled as part of kernel boot, hypervisor and non-SNP guests are >> subject to RMP checks on writes to provide integrity of SEV-SNP guest memory. >> >> Therefore, we need to enable these RMP optimizations after SNP has been >> enabled to indicate which 1GB regions of memory are known to not contain any >> SEV-SNP guest memory. > > They are known not to contain any SEV-SNP guest memory at the moment > snp_rmptable_init() finishes, no? Yes, but RMP checks are still performed and they affect performance. Testing a bit in the per‑CPU RMPOPT table to avoid RMP checks significantly improves performance. Thanks, Ashish