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 C1233E6F068 for ; Fri, 1 Nov 2024 18:32:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 47B786B008A; Fri, 1 Nov 2024 14:32:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 405206B008C; Fri, 1 Nov 2024 14:32:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2305F6B0093; Fri, 1 Nov 2024 14:32:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id ECA076B008A for ; Fri, 1 Nov 2024 14:32:44 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 69CFA120C41 for ; Fri, 1 Nov 2024 18:32:44 +0000 (UTC) X-FDA: 82738371366.10.17E1EA8 Received: from NAM12-BN8-obe.outbound.protection.outlook.com (mail-bn8nam12on2042.outbound.protection.outlook.com [40.107.237.42]) by imf24.hostedemail.com (Postfix) with ESMTP id 547E8180004 for ; Fri, 1 Nov 2024 18:32:37 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=amd.com header.s=selector1 header.b=bSaQCnj1; spf=pass (imf24.hostedemail.com: domain of David.Kaplan@amd.com designates 40.107.237.42 as permitted sender) smtp.mailfrom=David.Kaplan@amd.com; dmarc=pass (policy=quarantine) header.from=amd.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1730485782; 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=kHUPC37EGWnPKHcuK5ROYeSIEHiJg2nJ8tViRLOtqtA=; b=s0FQXNwas01M2IKN7q+iUVs6aLnTJ5IeE86eyzmFjlz0nAF8Ave8eaquT83BYOrO0LFZ8s WH68VoDJU1qzouc4qg4+2wbVEfr8bk0Cq251Y9k/MyaTUYLydbum3VyKIkBIQ/3LGkOfAM vMlKNL1BXwZSkNXxJZu6EnWpyTWHH2o= ARC-Authentication-Results: i=2; imf24.hostedemail.com; dkim=pass header.d=amd.com header.s=selector1 header.b=bSaQCnj1; spf=pass (imf24.hostedemail.com: domain of David.Kaplan@amd.com designates 40.107.237.42 as permitted sender) smtp.mailfrom=David.Kaplan@amd.com; dmarc=pass (policy=quarantine) header.from=amd.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1730485782; a=rsa-sha256; cv=pass; b=vF/TeypoaLschdqzBhV5/NjC9WIzEV6PRx4JQ91XRFl3mlS5rf4Hhyc+Lbil8zjOB+P31K qgYrZ+KQkJw4/i0VdXUnwFH7GqXS8tR0JKsB0oQRMvR8Gnf9v4IlzxPVcU0Nqq3aqBE85n R6aQiSV65+/6lEXN65Kcqxq5hDd45tM= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=eRZVlR5j3hqtxRQYeFXTSErUvx1RRubGlDVNTvEjEntIacgQ6BJLn9ArXKrJwTl3k7Ay5k1oUjnfNARhOmnYY9nHkmrjCRJ8abixZiCoizVVY8qNufsNn3PNwutWMfZVzsg7ps2TszsE9jFRG/z1hWuFe22iogk3N4iO0CChAxCyFN+CipGpgzJqZXDmrxS+cw1Q1eTJdvLh3kAxKdPpd5mKWEQyVnMP+Rm9nBhCt80aSqtkT58907iIGnPhUuQ8R4fLafRMomGDo74bO3nX61GMXkPZAOp7THHQFyHzu2aMnS7xMeSk2+fNC1TLNAwSX68na3mB1ZdHe0zO9khU1A== 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=kHUPC37EGWnPKHcuK5ROYeSIEHiJg2nJ8tViRLOtqtA=; b=HpM10Zm9yxi3G8gnx6S9xvYrlZBPEOAZAX9EvIYsv0WDJlAztH8L06iI2pTkpjTFlaauASVVZFRcBKg/Vb7oPBOopPjCo8qi5WU3bcXVLQHm6ywu13CbJptzM43MF24b3v8AU8ZjOiX/sY4GoTojLjSqUY2hfEwxOqk9OE54xGrhDpKHp2XItL9PgHmZdNb/l6zIocfqxmKNnQYfFtdCDGlOQ4Yyxc5cno1AcbSSC1woPhysHTi/pP94EWhpzs2fPwrJOUTdezZ6XbvIPLnmplecN9Eey6QN4jrsL62ZUV/efxDxfBzyuFFANCPGhbiuV31+HKQJIhAHYtqJzCEeFQ== 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=kHUPC37EGWnPKHcuK5ROYeSIEHiJg2nJ8tViRLOtqtA=; b=bSaQCnj1q8y+BfP4XvxUBKIe/oAFI2/nvu3T1rslfJnCr+z9WUfYONdZ/0qoY7tYL4XU6cH3YJRVjf87NHTmMNu1GdDtQ6rUX+VqXO8ZWm+Opt9xvswBE6+z9unJS+CIEeinVd1J0qwtNFgu8pp5Yd/JF2fwKg4ON+IpdxaRGkk= Received: from LV3PR12MB9265.namprd12.prod.outlook.com (2603:10b6:408:215::14) by SA1PR12MB7198.namprd12.prod.outlook.com (2603:10b6:806:2bf::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8069.28; Fri, 1 Nov 2024 18:32:38 +0000 Received: from LV3PR12MB9265.namprd12.prod.outlook.com ([fe80::cf78:fbc:4475:b427]) by LV3PR12MB9265.namprd12.prod.outlook.com ([fe80::cf78:fbc:4475:b427%5]) with mapi id 15.20.8114.028; Fri, 1 Nov 2024 18:32:38 +0000 From: "Kaplan, David" To: Sean Christopherson , Derek Manwaring CC: "roypat@amazon.co.uk" , "ackerleytng@google.com" , "agordeev@linux.ibm.com" , "aou@eecs.berkeley.edu" , "borntraeger@linux.ibm.com" , "bp@alien8.de" , "catalin.marinas@arm.com" , "chenhuacai@kernel.org" , "corbet@lwn.net" , "dave.hansen@linux.intel.com" , "david@redhat.com" , "gerald.schaefer@linux.ibm.com" , "gor@linux.ibm.com" , "graf@amazon.com" , "hca@linux.ibm.com" , "hpa@zytor.com" , "jgowans@amazon.com" , "jthoughton@google.com" , "kalyazin@amazon.com" , "kernel@xen0n.name" , "kvm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "linux-mm@kvack.org" , "linux-riscv@lists.infradead.org" , "linux-s390@vger.kernel.org" , "linux-trace-kernel@vger.kernel.org" , "loongarch@lists.linux.dev" , "luto@kernel.org" , "mathieu.desnoyers@efficios.com" , "mhiramat@kernel.org" , "mingo@redhat.com" , "palmer@dabbelt.com" , "paul.walmsley@sifive.com" , "pbonzini@redhat.com" , "peterz@infradead.org" , "quic_eberman@quicinc.com" , "rostedt@goodmis.org" , "rppt@kernel.org" , "shuah@kernel.org" , "svens@linux.ibm.com" , "tabba@google.com" , "tglx@linutronix.de" , "vannapurve@google.com" , "will@kernel.org" , "x86@kernel.org" , "xmarcalx@amazon.com" Subject: RE: [RFC PATCH v3 0/6] Direct Map Removal for guest_memfd Thread-Topic: [RFC PATCH v3 0/6] Direct Map Removal for guest_memfd Thread-Index: AQHbLHFMjLMyCV8maUKgtkq2gP29j7Kivv0g Date: Fri, 1 Nov 2024 18:32:38 +0000 Message-ID: References: <27646c08-f724-49f7-9f45-d03bad500219@amazon.co.uk> <2233397c-f423-40e3-8546-728b50ce0489@amazon.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: msip_labels: MSIP_Label_dce362fe-1558-4fb5-9f64-8a6240d76441_ActionId=412bc965-1282-46ef-82c3-d3676a9be80b;MSIP_Label_dce362fe-1558-4fb5-9f64-8a6240d76441_ContentBits=0;MSIP_Label_dce362fe-1558-4fb5-9f64-8a6240d76441_Enabled=true;MSIP_Label_dce362fe-1558-4fb5-9f64-8a6240d76441_Method=Standard;MSIP_Label_dce362fe-1558-4fb5-9f64-8a6240d76441_Name=AMD Internal Distribution Only;MSIP_Label_dce362fe-1558-4fb5-9f64-8a6240d76441_SetDate=2024-11-01T18:29:07Z;MSIP_Label_dce362fe-1558-4fb5-9f64-8a6240d76441_SiteId=3dd8961f-e488-4e60-8e11-a82d994e183d; x-ms-publictraffictype: Email x-ms-traffictypediagnostic: LV3PR12MB9265:EE_|SA1PR12MB7198:EE_ x-ms-office365-filtering-correlation-id: f2cf34b9-4b5b-457e-e941-08dcfaa38fe9 x-ms-exchange-senderadcheck: 1 x-ms-exchange-antispam-relay: 0 x-microsoft-antispam: BCL:0;ARA:13230040|366016|7416014|376014|1800799024|38070700018; x-microsoft-antispam-message-info: =?us-ascii?Q?aJQR+O09fnjj47ZLovde2xDH2UR/xeM01lIDlkyvbTKtPuU/Llw76M7WHlzs?= =?us-ascii?Q?c0RrVagrdsOTA/s3jPBOu208ZjqpXl1ZUC4XyrHx1I4fM0590MX1eiJEVl9r?= =?us-ascii?Q?6yMcWZKI7Brpp7BrFg8El7b3BmtgbIt6unZRWpcf154vh6j4v9duyWLDM4jD?= =?us-ascii?Q?s9YgXQAqORiyyPAvcWHGfpqslomQEEb2dLZ5FpgIwCp1QvyncL5AkPS/ouSp?= =?us-ascii?Q?MjqYiaEWxI7jX+wSx+2rCflrF57NhW67fSU6fxFGXLSwu2/wERAz1gyyUk4F?= =?us-ascii?Q?CZDwl/YvUdQ4QbXfJWcHqJxWlepA0zkTHd69vJ5b2aQrgt2uKDmuRSpcgI/u?= =?us-ascii?Q?LUXftreGn5kLOpyuCOs3gyTy7UXHiocJAUM95QuaDllQqlQ11M6P+KLjNI3V?= =?us-ascii?Q?AZkrvgqpTGnm2BOmck9knGba4ixQnhLmjHZl0zzVsFzEu108I7ZT9dOIdTPt?= =?us-ascii?Q?ZvhSjdbTsMT6AjNHzh/2qWBGWim3JZnC5PYT11RvGD7yTTad1vnLAcyM9fZM?= =?us-ascii?Q?3Dy4QAE7gqxjdMvwUE8OvueWzaqxvpAuQB/Cu2UeSabcr9xL8oQjMrtnSn+e?= =?us-ascii?Q?2fttmm6zY6J7T6NbyJTA1lhgfYa/WkUAlztdlVuPoikKE2nKZwN3gFxVGoYS?= =?us-ascii?Q?90nsWZ/QigEb4nNQZgp1UQqYEO9+s6+4DC5/RTuwnx0uEeYk3vBUC6/VM3IA?= =?us-ascii?Q?v3P7jJIIIukL73SIyjU/aOvUV6CHk0aQkQFQCFO+3mroPiG9uSmeK5pEi6uA?= =?us-ascii?Q?yR/7YVOiWmaFt8mDR+WtDlnHZgns9l3j5VHUa/V8TTtN6ggry2UXDJn/v+Mb?= =?us-ascii?Q?w2EmV0opnUMJzfum4D0U1kGXY70U6NMootyseII2EmuLDLKxzyOneahoNwP+?= =?us-ascii?Q?3QwJ/KTpLetchZ7ZNeAj0KjxyYM0ZhT7oNOYfiS1Ykj0hQyOCcGAzB1xBBM7?= =?us-ascii?Q?Bw2crZAlU11XjPRyswrPfWnL8RcEQBb45SC+o5OEYWAjl618jcpb0sIWAwrk?= =?us-ascii?Q?7zj1X7zbDOhzgRVk0IOhqUnKvQvh+iUYIiS2vdpK4aqxOnwiqOU5ZZQtYbdl?= =?us-ascii?Q?NuEY8yHUSvVRAWtLmvsKEqLmIQwl2Jo90UnCfBICHiuEQkYomiwom3aOi6sS?= =?us-ascii?Q?OD6yi9qTB/1ny++Yhj/zUYcxkgRT45jNsR6MlkWtqelP5LZyQKXioxqOtWCj?= =?us-ascii?Q?3aSks3hoQ2/+03qVCqO0tJQGHMGksIUKip2TLU7cfsupa7AF9OP/qbOQ1RaS?= =?us-ascii?Q?g0qpTD3nZQhzRR9HoKC52+QeBIY/CN15FbU9WoaDfUIYl3Q65jGBHB57vu8u?= =?us-ascii?Q?7Er74b7jIjDhppCb9aruzB6LxdXVC2t3A9NFTzMsd1uKZVglylBWKSAl64C0?= =?us-ascii?Q?ooXSL5w=3D?= x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV3PR12MB9265.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(7416014)(376014)(1800799024)(38070700018);DIR:OUT;SFP:1101; x-ms-exchange-antispam-messagedata-chunkcount: 1 x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?KDdQKwnWYRiGTcOlRzhBWSpMmrIgmyOgQfKIhqsdYWQFDVzt7pQyPZsZAfks?= =?us-ascii?Q?Klk0WA83V0qLuhimnK5DMUEDm7EPaQEpaSQgYOkJ44QO6wShBJblTHBOpH6E?= =?us-ascii?Q?3NDpRQ9O5kvTRHcsS4jeg42rm+K8BL7aPttHBmZw9nqnRoSX3swcjFhszQ7g?= =?us-ascii?Q?VXETqoL/ITVa6Hiau9MUBOnpF7MVA0rN0msOc0ab7q4xWnsFgHDHvQM0tbj1?= =?us-ascii?Q?w0SsL+XrhZB/mX9wUDlDMiT2mtCBDkPARuY2duMXZU6GuUReuOhy7pdisS9q?= =?us-ascii?Q?mv5f4Ki/zwIpxijvysPFBgrORdGCWWcp3ztvwXDrgavPWCEWc+12THM2N+Qm?= =?us-ascii?Q?2fXD3G6Jihz7+vsQSPpCzABRTfLBakodNC1gWBXRlvuKojCQQ9IRZvhRdcwb?= =?us-ascii?Q?5A8+WYwSG9JVfcHZ5blBmfZhZ/Holkqcyb0tp3NOegbw0qnY3KMtq++KyP9k?= =?us-ascii?Q?+2D7QsybM5akfgQ2vNSVOy6FhfbXTin0GG66qSjLMeXi9t/5Fp67rEv8qN2a?= =?us-ascii?Q?ZVNbtGSSSzyygNY6cYxE2STKRSbs6bDV5VpWUh8WGsuIxuKa6j05UXbhTjkO?= =?us-ascii?Q?W1GlO//01LRiXiC3CIbJU2KJaZdLVTgF6tvhHTqTRgj6nt2PvadUDa530Uh2?= =?us-ascii?Q?P4zhZjTa48m5d9XPvvs0JUnEWhvRomFVogOfFHTyRhUysKJhxVkLcszNlgKl?= =?us-ascii?Q?KmuwJKJ5AtyrpirZY4A7M0R4DTc5zsDyWSCwLZHiWkv1mYJrKMKoPVCk1Ey7?= =?us-ascii?Q?lbDSoekqRo17gl/wPUXX/fe1CHIa95LKRlAYSKDKblCbFTYzbf0Sumu/4Pls?= =?us-ascii?Q?h+dqvEdaK9Klgay4nSvsLQc0IvBspD0XKQNBfFG5WqESpeZDVj4QMweP2bDq?= =?us-ascii?Q?iacWSsJw26XVrCdKdcBgzlLoE5ZruDG8UUzdvm+I5XjrDTxjQDHDLS4S1y5F?= =?us-ascii?Q?1yMwJcimB2uLZZRcKpr12LVnh6HARaU9Yq12QPnUbypdFe0mhboTpg0ELJBt?= =?us-ascii?Q?z/ocLth3MPcwDmV33Y/xNthSYqLxwEb4bPDNrMJ37UnxFQviBf1h2CnY87zT?= =?us-ascii?Q?6g3Fs8SXtlBk64dTOpZfSi0/Z06QL5DBwLRJQ1BrhGn7wQN6muqXrklsH7Um?= =?us-ascii?Q?Lowcnj2gANTeKDDi1wdSmgUBtL1PCbdq5gk5xe2jCbUgAGJNzRqEHUdgpnPE?= =?us-ascii?Q?afByuD+iqJb39cCIeFB36x0Sjz1urVkqKRklMafxEMy9FfDxW/hoxiVWb7yj?= =?us-ascii?Q?WHtH0pEwQ/akDwXL0jUdBe50fhTjP6Q/JELShvQdfXwini7Wo26cu/X26Jer?= =?us-ascii?Q?o7UUZvxIrU05zl0XjIc/ktUncKsz1tqlrP+V/dIvx27EM4UmUxwxWUP+FX7b?= =?us-ascii?Q?A0gyFlq37YQsZheO0mzmi0H1n+DNIN10XKlcx6VWEmnwlpuaGv9Dt8Mjm41w?= =?us-ascii?Q?KII2z0ro8Kg9AUGuMGThSDc4YjL+y/iwn2XpCPNGN1YyFhPZ7rngL/SEBmCB?= =?us-ascii?Q?u3HOxXKvX6M+q8oV4JL1blE1a/mHPSQGpG2iLuoyoB4tMYIuWcxyPOzUz6N6?= =?us-ascii?Q?Vyno17j+ZVCwMpgrvcw=3D?= Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: LV3PR12MB9265.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: f2cf34b9-4b5b-457e-e941-08dcfaa38fe9 X-MS-Exchange-CrossTenant-originalarrivaltime: 01 Nov 2024 18:32:38.0505 (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: 3DRxfjXFmkfnfRxP91h4yuircTS0cTRkFMnXV9WNrHHh0+7Y7CorGFbo73beV2gL X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR12MB7198 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 547E8180004 X-Stat-Signature: 976ichkjmnmcsjbbix3jnmrifwzm9nu4 X-Rspam-User: X-HE-Tag: 1730485957-339641 X-HE-Meta: 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 bBHBOiwC 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 QEO6A0Uo GLVeh3mP2MUVH69l2h4LcigIuj93OipjiWeRRHDq/F92HG9S7+Zc7BJYPMVOJso5U5x98luTZGVlReuQEp/hC6Q11wl3yNxI9a7wvuitbumJUYbOQl58GqO180BdZBUQR2K13GiBsqPTM+4mGGW8IPH6bq8bjYRb9GG89FGc1KRHFMjTsCU9g5dqpBe5qukNE1EkO2tYRiBVpGA4yTss2ZiYLihXDjqkFn/6kt6KFuvW8T6hgqRDrQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000006, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: [AMD Official Use Only - AMD Internal Distribution Only] > -----Original Message----- > From: Sean Christopherson > Sent: Friday, November 1, 2024 10:18 AM > To: Derek Manwaring > Cc: roypat@amazon.co.uk; ackerleytng@google.com; > agordeev@linux.ibm.com; aou@eecs.berkeley.edu; > borntraeger@linux.ibm.com; bp@alien8.de; catalin.marinas@arm.com; > chenhuacai@kernel.org; corbet@lwn.net; dave.hansen@linux.intel.com; > david@redhat.com; gerald.schaefer@linux.ibm.com; gor@linux.ibm.com; > graf@amazon.com; hca@linux.ibm.com; hpa@zytor.com; > jgowans@amazon.com; jthoughton@google.com; kalyazin@amazon.com; > kernel@xen0n.name; kvm@vger.kernel.org; linux-arm- > kernel@lists.infradead.org; linux-doc@vger.kernel.org; linux- > kernel@vger.kernel.org; linux-kselftest@vger.kernel.org; linux- > mm@kvack.org; linux-riscv@lists.infradead.org; linux-s390@vger.kernel.org= ; > linux-trace-kernel@vger.kernel.org; loongarch@lists.linux.dev; > luto@kernel.org; mathieu.desnoyers@efficios.com; mhiramat@kernel.org; > mingo@redhat.com; palmer@dabbelt.com; paul.walmsley@sifive.com; > pbonzini@redhat.com; peterz@infradead.org; quic_eberman@quicinc.com; > rostedt@goodmis.org; rppt@kernel.org; shuah@kernel.org; > svens@linux.ibm.com; tabba@google.com; tglx@linutronix.de; > vannapurve@google.com; will@kernel.org; x86@kernel.org; > xmarcalx@amazon.com; Kaplan, David > Subject: Re: [RFC PATCH v3 0/6] Direct Map Removal for guest_memfd > > Caution: This message originated from an External Source. Use proper > caution when opening attachments, clicking links, or responding. > > > +David Kaplan > > On Thu, Oct 31, 2024, Derek Manwaring wrote: > > On 2024-10-31 at 10:42+0000 Patrick Roy wrote: > > > On Thu, 2024-10-31 at 09:50 +0000, David Hildenbrand wrote: > > > > On 30.10.24 14:49, Patrick Roy wrote: > > > >> Most significantly, I've reduced the patch series to focus only > > > >> on direct map removal for guest_memfd for now, leaving the whole > > > >> "how to do non-CoCo VMs in guest_memfd" for later. If this > > > >> separation is acceptable, then I think I can drop the RFC tag in > > > >> the next revision (I've mainly kept it here because I'm not > > > >> entirely sure what to do with patches 3 and 4). > > > > > > > > Hi, > > > > > > > > keeping upcoming "shared and private memory in guest_memfd" in > > > > mind, I assume the focus would be to only remove the direct map for > private memory? > > > > > > > > So in the current upstream state, you would only be removing the > > > > direct map for private memory, currently translating to > "encrypted"/"protected" > > > > memory that is inaccessible either way already. > > > > > > > > Correct? > > > > > > Yea, with the upcomming "shared and private" stuff, I would expect > > > the the shared<->private conversions would call the routines from > > > patch 3 to restore direct map entries on private->shared, and zap > > > them on > > > shared->private. > > > > > > But as you said, the current upstream state has no notion of "shared" > > > memory in guest_memfd, so everything is private and thus everything > > > is direct map removed (although it is indeed already inaccessible > > > anyway for TDX and friends. That's what makes this patch series a > > > bit awkward :( ) > > > > TDX and SEV encryption happens between the core and main memory, so > > cached guest data we're most concerned about for transient execution > > attacks isn't necessarily inaccessible. > > > > I'd be interested what Intel, AMD, and other folks think on this, but > > I think direct map removal is worthwhile for CoCo cases as well. > > Removal of the direct map entries for guest private PFNs likely won't aff= ect > the ability of an attacker to glean information from the unencrypted data > that's in the CPU caches, at least not on x86. Both TDX and SEV steal ph= ysical > address > bit(s) for tagging encrypted memory, and unless things have changed on > recent AMD microarchitectures (I'm 99.9% certain Intel CPUs haven't > changed), those stolen address bits are propagated into the caches. I.e.= the > encrypted and unencrypted forms of a given PFN are actually two different > physical addresses under the hood. > > I don't actually know how SEV uses the stolen PA bits though. I don't se= e > how it simply be the ASID, because IIUC, AMD CPUs allow for more unique > SEV-capable ASIDs than uniquely addressable PAs by the number of stolen > bits. But I would be very surprised if the tag for the cache isn't guara= nteed to > be unique per encryption key. > > David? How the stolen PA bits are used is a microarchitectural implementation deta= il. It is true that the tag will be unique per encryption key. Beyond tha= t, I'm not sure what other details are relevant to SW. --David Kaplan