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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2AB3DE83840 for ; Mon, 16 Feb 2026 23:08:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id AC3A06B0088; Mon, 16 Feb 2026 18:08:14 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A70E26B0089; Mon, 16 Feb 2026 18:08:14 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 929396B008A; Mon, 16 Feb 2026 18:08:14 -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 78AC16B0088 for ; Mon, 16 Feb 2026 18:08:14 -0500 (EST) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 055BC5AD94 for ; Mon, 16 Feb 2026 23:08:14 +0000 (UTC) X-FDA: 84451860108.26.A58648B Received: from BN1PR04CU002.outbound.protection.outlook.com (mail-eastus2azon11010037.outbound.protection.outlook.com [52.101.56.37]) by imf01.hostedemail.com (Postfix) with ESMTP id C566F40002 for ; Mon, 16 Feb 2026 23:08:10 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=amd.com header.s=selector1 header.b=h2oMTVMl; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf01.hostedemail.com: domain of Michael.Roth@amd.com designates 52.101.56.37 as permitted sender) smtp.mailfrom=Michael.Roth@amd.com; dmarc=pass (policy=quarantine) header.from=amd.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1771283291; h=from:from:sender:reply-to: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: references:dkim-signature; bh=4G9gz7Ljfmc1VNZla3l7zPoahrJD3eH99MSZjoT3Ags=; b=VRyOw3dSsNjyY+znnFjGcIe/W0fGSkWTOaXSllZ9j/n262/D22FD5qq06InRmUVlukLhlR /6edRZ+1BLB39nXqG6AC9xG/weHZnwGaLlXRP/x1FNsCuFVw+L+XWnBzuvqKK2JjTDxS6y XO5q1bzAwfCzUcqg1wUYrbt1R3+w2nU= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1771283291; a=rsa-sha256; cv=pass; b=FrKE4p73Bw7lElgOyvQ0RkrjX1fnTVw20NQON5P7E94mN436Z/XGCpympupb6dXZBVVHFh gknURiPG5+c1Zn2DjuZLk4ficHO2u4zqVOXpkwlWZ54Eeh9KsOQ0bYQw3aS3b2YNSuU+xC MxGHDsIkvlyz1rwrydXHizfoaFiVDzg= ARC-Authentication-Results: i=2; imf01.hostedemail.com; dkim=pass header.d=amd.com header.s=selector1 header.b=h2oMTVMl; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf01.hostedemail.com: domain of Michael.Roth@amd.com designates 52.101.56.37 as permitted sender) smtp.mailfrom=Michael.Roth@amd.com; dmarc=pass (policy=quarantine) header.from=amd.com ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=ak6/A+cfRCwXoMSbQa/8XGvmk3uWbMMLCTrCQkKwQXNUkge1xOPolMJIKSI3n9bKmV++zxQbHav3LLd2taXCR8a2nS3MNiChKtllSUJn/1/qIBYr1aryCw48x69l3U+ZIao/1x/fDBdEpVLfa22r4ZnhseFGxA9gllRJ5wxM5Ljw0Vf7CFsDv6rqmFys+sEHaYt+Qv2M5H3FSxPNV5pTRJZ0ySrbtMVKMb7n0tDwKGYOqvLsGi896FlD2P4jkppSn+u/IaUNdk65I3f/EQJhTEv2Oy/75ioLCNNpdcbJvr0Lv/T7nIBZiEzWymscWHhQZd7rkGP3I6lTwYV5efQyRA== 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=4G9gz7Ljfmc1VNZla3l7zPoahrJD3eH99MSZjoT3Ags=; b=OUfCiFT+hXGP4PCBvovBLAVgYVZvl4f4QvAiIXy55pPtRrmlV6br7r3j3vu+fDrfyNrOotuVkwiBHU9+sjT3i3r4SxCQXRv3rv3OApvYqGK1WllttJzWEAcF3HiEWJdkLPg2YFSPurINax2aMw8iUtsCs6S2woATZbOUK4ja9jZs2Zb/h1ZzbdlqzUSxjmoMOGkInt6uWH2IygRp3920+1KJ+2+mXJ3SzcFA5fsG3R4WqsMwNpYWt5nK6Q6NQyeKTlKtWVdVj93rjgCNID6UfDEd+liaDfYHgHBZCoYgg1FLrm9W/YikApN2fd3iH1dN0HW5A61dpLxB3X55epoQ1Q== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=vger.kernel.org smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none (0) 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=4G9gz7Ljfmc1VNZla3l7zPoahrJD3eH99MSZjoT3Ags=; b=h2oMTVMlixVLhr1T4+XIk+AXvMWWTDQngh8q0aM8wv2BVtr8Y9Dxj4cWTuUn9UZ5ClImJZ4zct2O2DB676t6HXLFlW0ULWAw288f8QZ0Kcf3h6EsdGvfV1I9oLEbPdC/iPUpoI4hsKKzYaqD9Qxv/4LhDJUrbLt6EhBTkwr5zmc= Received: from MN2PR16CA0066.namprd16.prod.outlook.com (2603:10b6:208:234::35) by DS4PR12MB9817.namprd12.prod.outlook.com (2603:10b6:8:2ab::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9611.16; Mon, 16 Feb 2026 23:08:07 +0000 Received: from BN3PEPF0000B071.namprd04.prod.outlook.com (2603:10b6:208:234:cafe::26) by MN2PR16CA0066.outlook.office365.com (2603:10b6:208:234::35) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9611.16 via Frontend Transport; Mon, 16 Feb 2026 23:07:32 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 165.204.84.17) smtp.mailfrom=amd.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=amd.com; Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by BN3PEPF0000B071.mail.protection.outlook.com (10.167.243.116) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9632.12 via Frontend Transport; Mon, 16 Feb 2026 23:08:06 +0000 Received: from localhost (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Mon, 16 Feb 2026 17:07:48 -0600 Date: Mon, 16 Feb 2026 17:07:33 -0600 From: Michael Roth To: , , , , CC: , , , , , , , , , Subject: Re: [RFC PATCH v2 00/51] 1G page support for guest_memfd Message-ID: <20260216230733.ejxtppfrbjaarftb@amd.com> Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit X-Originating-IP: [10.180.168.240] X-ClientProxiedBy: satlexmb07.amd.com (10.181.42.216) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN3PEPF0000B071:EE_|DS4PR12MB9817:EE_ X-MS-Office365-Filtering-Correlation-Id: 84c8907e-7de4-494e-36d6-08de6db03eda X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|1800799024|30052699003|7416014|376014|36860700013|13003099007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?a212MUhFaHp2VWtDWUtobytTaDFyWDcyOTluaFpMaEl2cDA2czJIY05CWVND?= =?utf-8?B?ODN6TUZ1TzNjMGRaT0tFV3ZMZDRDWnZwY1ZRTUZORkxBZDdzQm5VMGlKeklW?= =?utf-8?B?SVFBTWFIakljMEZ2VS90bDgyT1hxZGJmNGdxL2FIeXlTamdlZG5ST1Y2Zmtr?= =?utf-8?B?YjJ2VVFhNmhlb2JzMnJCSjgwVjdtY3gwbk4xTmE5ak15RERKRWRzQURHTEdR?= =?utf-8?B?S09PL051d2pmVTZSdXNjTFNhcEZlalM1RFZSZUZDM1NRemltRW9NSEVZY0JQ?= =?utf-8?B?SzNDK3kzbStLcTJyZlArTytXNjdMdSsrOGV1TE1PNXJLVFJOYTdueEVLQTJY?= =?utf-8?B?bHQ4aFhaS1VuK1Fod3duSXR0eWRwZUhKNWQyTnBWSktjNXhaUVdtTUdDQldB?= =?utf-8?B?RkJoNmQrMEE1ZVIybXVTU2FkRmMyeWJMaEc1T1UrWlA1SEhmTTJQNkZJdldz?= =?utf-8?B?ckZMRkVNRHRETmU3UE5sUGs0b2dmbktERE10a3RQR2hWSWR2NHRNSUdRUnk1?= =?utf-8?B?NTFUOXFtRDltd2twcGpHMUpIRTFGU1ZiRm5XOCtSMWhRdGorbG1DUUdsODRM?= =?utf-8?B?VEp6ZDZBQXoyd29HVXNzcU56aFJWVzk0enIrazVMU3RZYTd1ZmkrVnJ1bVp1?= =?utf-8?B?OGdCVGRIUWV3OCtCZDdDOVozenliT0ZFM0E3OFdlRDFrbkFEb1ZlM2lhZ0NI?= =?utf-8?B?bmVvRWtFZWZPdWlmbmxmR3JBVUxhcE1HSkpVZWN3NTV6eWdWdmw5bGE3eUNz?= =?utf-8?B?RDJoUENiZmIwOGVFVHlHdkh6NUVUOU93cThWTmNkRGYzck0yekRGcVFVZ21m?= =?utf-8?B?aktzNWU5NkVLM3U2djEzbHBqOHJBd0pjakl4cTUrNE10Yk9uS0YzZkNhNk1w?= =?utf-8?B?Ung3WGRwbjhLVzRRcWNUYXhXcEZoNWZIM21ZQ1kvbkFheWM3NzNCWFNrMlFq?= =?utf-8?B?eWFMMEdneFQ0ajBRK0h5cWN5a0poSlk2ZS81QThYUy96TnRyRFhZYkdDQ3hB?= =?utf-8?B?T0x1NXlDa0NQOUVhM0czZ2hDK2dxd2RKK25aTFVhVmFld1BOVGlKMzltV0hH?= =?utf-8?B?Z2lKcGZhcC9Wa1QwZ05iRml5S3lqNS9TeEtLZVc5ai9UWmQrdVpjN1licVhl?= =?utf-8?B?RlFrS1NTVEsvSUs5ZE5Zc3lYZ3duOVNwVkpDYzdXSGNxb0V0Ulh3d2lrY25G?= =?utf-8?B?VU5Ra0pMZklGOTh5bmh6UTNVWUwwbm1WdEFGNnJuL0F5MXZQSXVXeFljNVB1?= =?utf-8?B?cmF4eitYN1RlNFlPKzMvU0FVaUE0NnpMVjVkMEJVblhlVWtpNENycGxoK3lx?= =?utf-8?B?b0ZEM1Y1WHFIMm9ENUg0MUZDWGcwQmpYUXhkR09KZTQzMUszb1FGWE9malFs?= =?utf-8?B?NjdnNzdkUlFCVDB1Z2NhTlovMldHMWMrQjdHT2RDZ0hOYk41eHdCTytvcERI?= =?utf-8?B?U3I0VTNFbXNGdGVjVDI0a1JQSWw4SERYRG5FWnB2YlNRQ05YVnBpbWtKYU93?= =?utf-8?B?clFzWW01Y0xzSjNBR2VqbVZuekd3U3pQVUJXNWN6eEZzeGJWT1M4OE1MOVp4?= =?utf-8?B?ZFRrMTYvVE80bWdUalNtODlRcTY5RnVLTHhIT1dYUHVmWEJvaEovSGQ5b1RR?= =?utf-8?B?c1p6cmhtUEQvZ3pKQTFwaWdiMjBxWjRoZmhIdnRIY0E1b0FNdkFuR0g1cTIw?= =?utf-8?B?ZzJkQm90ODczSVIwckMzQXhEa2JGSnNMZUc0bHRKSXBDR1cwT2tJcGxYNUx3?= =?utf-8?B?SlIwTXpNU0J2TDNNQk0yMkN5YjJPZzFCZ1ZocUFJNmZkYWd5UWZmWFk0NWIr?= =?utf-8?B?bmsxSTltbERuaG90bkdRdmV6bU9PY3VlSTRNR3pZamV6U2QzWFkrVDg3QXdU?= =?utf-8?B?M0NFSWhRaUorMHI2U0lINGRyTW8yU0h6dEczTWxHNTNrK0JhdG5hdmNTeG9u?= =?utf-8?B?Vk9QQmx0RFNuWXVpY0hWVFlscnhtU1RDVHhmcHJKeWJtM3ltVnJsRXZjTXlu?= =?utf-8?B?THViVU84NTEwVVRzTXhqakRZMTFYUCsyeFY1bEtqTHlYQXVTclVLYjArZ0Rq?= =?utf-8?B?WFh6ZEtmVm1FNVc5Wmp4a2hacUYrQ0tqN3lScmdFQVRYRXNLQkFjMjc0Z3lq?= =?utf-8?B?NVZzYmdoMStETWdvNkE3VkZsemR2VFdlUVBMamVQY0ZaUkdjRUxvUTF6bVRH?= =?utf-8?B?YVNEazA0WVI1clpkeDdWc2JpT3lVbUVVdUVPZUxSc3ZUK1RLWTRKd0dxdXVY?= =?utf-8?B?RnRPRms4UlphcmR3bUR0RS9QcGhBPT0=?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(1800799024)(30052699003)(7416014)(376014)(36860700013)(13003099007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: ADu8qfkSJkjT+82bA94PIR3m5qKrLYeTrY2WGZwV8qvojldupWDSWgzdLhAFScBKdViE7djms5qu3ro4QUMe9BLog/97RMOuxQ1DDWhsR5pwzHabUFuT8MwAD3dvIDdyEg9m8GPUnBoKj5AIFeFWe/8f9TlQpr2KG4o1DG2rrKIxs0ojqeGUjMPcPg2jEw/Zsnuxy7ItG7W7mvepET4raFqQeUsWmJuz56ZJ74qX9lVVpWGvWeT8be59wlr9hgbfzksZJtOMGwutL7NK84W7EeypUG1rIbH4qyQYxFYKnIcQYbg0x104u04Mus6FB4LLZK7x05Sb630fiTGfUFI0t8s961AcIIEOxSk5SVg+GTM+R7hXc+KFrQWE5pS11Kg92x84kQ6OTC8Lmw2dmcR2zGUhAiD63r/R2hpiCnkViWdBp/iKQRpqnc1GrJgRc6tH X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Feb 2026 23:08:06.8885 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 84c8907e-7de4-494e-36d6-08de6db03eda X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN3PEPF0000B071.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS4PR12MB9817 X-Rspamd-Queue-Id: C566F40002 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: 83wpipwaseirb341d1r7yhkndj39ii4y X-HE-Tag: 1771283290-890383 X-HE-Meta: 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 AUQqi1hH 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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: I'm not sure I'm hitting the same issue you were, but in order to fix the race I was hitting I needed to grab the range look outside of the kvm_gmem_get_folio() path so that it could provide mutual exclusion on the allocation as well as the subsequent splitting of newly-allocation hugepages. Here's the patch I needed on top: https://github.com/mdroth/linux/commit/240e09e68fe61bb0dfad6a8e054a6aa9316a3660 I think this same issue exists for the THP implementation[1], where a range lock built around filemap indicies instead of physical addresses could maybe address both, but not sure it's worthwhile since THP has been deemed non-upstreamable until general memory migration support is added to gmem. I'll dump the code below though for reference since I know some folks on Cc have been asking about it, but it isn't yet in a state where it's worth posting separately, but is at least relevant to this particular discussion. For now, I've just piggy-backed off the filemap invalidate write lock to serialize all allocations, but I've only hit the race condition once for 2MB, it's a lot easier with 1GB using hugetlb. [1] The THP patches are currently on top of a snapshot of Ackerley’s hugetlb dev tree. I’d originally planned to rebase on top of just the common dependencies and posting upstream, but based on the latest guest_memfd/PUCK calls, there is no chance of THP going upstream without first implementing memory migration support for guest_memfd to deal with system-wide/cumulative fragmentation. So I’m tabling that work, it’s just these 3 patches on top for now: 2ae099ef6977 KVM: guest_memfd: Serialize allocations when THP is enabled 733f7a111699 [WIP] KVM: guest_memfd: Enable/fix hugepages for in-place conversion 349aa261ac65 KVM: Add hugepage support for dedicated guest memory The initial patch adds THP support for legacy/non-inplace, the remaining 2 enable it for inplace. There are various warnings/TODOs/debugs, I'm only posting it for reference since I don't know when I'll get to a cleaned up version since it's not clear it'll be useful in the near-term. Kernel: https://github.com/mdroth/linux/commits/snp-thp-rfc2-wip0 QEMU: https://github.com/mdroth/qemu/commits/snp-hugetlb-v3wip0b To run QEMU with in-place conversion enabled you need the following option (SNP will default to legacy/non-inplace conversion otherwise): qemu ... -object sev-snp-guest,...,convert-in-place=true To enable hugepages when using either convert-in-place=false/true, a kvm module turns it on for now (flipping it on/off rapidly may help with simulating/testing low memory situations): echo 1 >/sys/module/kvm/gmem_2m_enabled This tree also supports SNP+hugetlbfs with the following in case you need it for comparison: For 2MB hugetlb: qemu ... \ -object sev-snp-guest,...,convert-in-place=true,gmem-allocator=hugetlb,gmem-page-size=2097152 For 1GB hugetlb: qemu ... \ -object sev-snp-guest,...,convert-in-place=true,gmem-allocator=hugetlb,gmem-page-size=1073741824