From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM11-DM6-obe.outbound.protection.outlook.com (mail-dm6nam11on2057.outbound.protection.outlook.com [40.107.223.57]) (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 C2EF117BA1; Tue, 15 Jul 2025 22:56:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.223.57 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752620166; cv=fail; b=SlLL4e1XQi6qZZ1LkuXxo/wrkQxJegiv60twcYFtOX/WjoXiLF8p/QbK8NFAXNM5Do66PqHw+rPjdGE86txebfWxo4dRLEXqcM6+tPkSxUuIGQU2m3SxyfW1+ICMyQLNFmgeEYidBgEvsXKuhuA7DNz5evex/x/q0/rB3+dRd5o= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752620166; c=relaxed/simple; bh=aAVGAgRI7TWP676JBCOhsIv3mKjxRU4SobCYiekkpOs=; h=Date:From:To:CC:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LAYCQCZZ9IPRdRAJByiFxxWF9V5Z9efhzX5+RSUeLRu78GNEOKP2Sw7sVHJ5P95KOS1MwjaZZP0ZjtpH5G5DVLNg2s+8JjsvWw4wkPQOnt17EAZBDTMKZJ4KNG3gEkqGacdXAlgqawMyQY/LjfB+QBWuCb39EeC7YNMGnlPhuP4= 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=AtBVXktA; arc=fail smtp.client-ip=40.107.223.57 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="AtBVXktA" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=QBT8GOEwmNso58uhQshNiFZJ3UVtus6+qu6YbXDNiBOJ1ttc5pVO3TK0eOmaK4sE5/0XTSEOaoZanm2UatSUs5aK1NPh1OGRNHcDTexNOSRbHxOU/OrhJEis3PJsbL6+GlpwKaCBqgA/gY9x6rBRCffF8ddC27YJ9xt/ZaTz/IqCeNoKXZMKlNhAQSzFkzl8fjhxqrW/3aPQx7r52+qxBIlfuz4Cbp5DA1m5pdto1l+NTcD8uaM2k/RAVX0QaJ8NyDW5bxiqdYWb06ReVTv2LW8y0iuH4xyoomnIQwXnTz51fZsbssd42Fcwp4mdUbqNFdD4+LspigsgbifGo8I6jw== 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=8Y678HHSQDH8/+Qj3NFpMXyWFC73x5o59TJyKcD2n0w=; b=iPG/Gf07BFdLf3XsUXpuHHBtaRrZdY/FhuCeO3g7+kDLPEdAYO26uU089CqAyerrV8Yk2A5+wZu3xtc5+mpnDW+NSdSyfz/LacCa0R69w7m+ufC7ny03hoxscdbPIWkk3HqcI9u1pQAvs7+JhfDmR2n3/Nx73fDVgYsFINdpNOBm92/Fa2QfHb6F1HdpPvVxe1nx3FIK3Auj1GfWdr+3EAb21kaiHAIuIa/a7A/B+FwmVBytmdbxTN4hQOoh9Qx453Pk4Jh4RnaT9tVu+8FAPJpsswGZeakAcCCh6PTKYeiKnUsxPZNc/fZnEgLaa4kmBP54EgPi7ciqQgc9EWJ+4w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=google.com 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=8Y678HHSQDH8/+Qj3NFpMXyWFC73x5o59TJyKcD2n0w=; b=AtBVXktA2PQHFVAQZV9jbOlTl8WaVBT7eFv39Mj+jMLiDvw+8yuzli11y/G7NsXSFAjhpQg2TlNmHRtcKgzcuflI1o0aTRpm4szTAVxcN4lpLZOTZMgyZx1QGFWMTBfQ79/yg9/c1SOuMhS6YN+yyzO9UHo5TBb2qgqia+v+rdc= Received: from SJ0PR03CA0216.namprd03.prod.outlook.com (2603:10b6:a03:39f::11) by PH7PR12MB5830.namprd12.prod.outlook.com (2603:10b6:510:1d5::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8922.32; Tue, 15 Jul 2025 22:56:00 +0000 Received: from CY4PEPF0000EDD4.namprd03.prod.outlook.com (2603:10b6:a03:39f:cafe::7f) by SJ0PR03CA0216.outlook.office365.com (2603:10b6:a03:39f::11) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.8922.33 via Frontend Transport; Tue, 15 Jul 2025 22:56:00 +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=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by CY4PEPF0000EDD4.mail.protection.outlook.com (10.167.241.200) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.8922.22 via Frontend Transport; Tue, 15 Jul 2025 22:55:59 +0000 Received: from localhost (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Tue, 15 Jul 2025 17:55:58 -0500 Date: Tue, 15 Jul 2025 17:48:25 -0500 From: Michael Roth To: Vishal Annapurve CC: , , , , , , , , , , , , , , , , Subject: Re: [PATCH RFC v1 3/5] KVM: guest_memfd: Call arch invalidation hooks when converting to shared Message-ID: <20250715224825.gfeo5jdqjlvtn66l@amd.com> References: <20250613005400.3694904-1-michael.roth@amd.com> <20250613005400.3694904-4-michael.roth@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-ClientProxiedBy: SATLEXMB04.amd.com (10.181.40.145) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CY4PEPF0000EDD4:EE_|PH7PR12MB5830:EE_ X-MS-Office365-Filtering-Correlation-Id: e4d62f4c-3cb1-41ed-35c1-08ddc3f2c408 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|82310400026|36860700013|376014|7416014; X-Microsoft-Antispam-Message-Info: =?utf-8?B?YkM2c2dWeEwwS0tXQ0xXOUNBbHpYeDgxTVRoWHZNclIwclgwaDlYdy9uOEZn?= =?utf-8?B?VHI0UGxIU3M2UmY4SHhMeTR0c09abnRtWTFuSGVJelRCaW5TYjVHYUk5VFpL?= =?utf-8?B?RENqNUtqQWlsNzVSUlIraEdTUFdwWlRoRkdWWHVYTnZuVkgwYTdqdFhlSGo2?= =?utf-8?B?Nkd5ZzdKa29leHZKaHNLbkVHeGZLdXhTMjgrWHFMSDVzN2loS3pNYzVVZkds?= =?utf-8?B?M2M2eHBuT0FLSlV1QmFrek1Dc2I5eWUxTDJ0Q044YUdad1BRekZvWktqaGEy?= =?utf-8?B?T1FUUGFyMXB6ckpqQWVWaHVtVmZVai90YS9QSWZpWFRBaXFLZUM5bzR1RHJn?= =?utf-8?B?YVZxY29WQ1BQK1FTTVBkM1J3amJ4bzRoV0VTUkJiV1ZUSGllNG8rdVJpWkU5?= =?utf-8?B?bjdTSXF1ZExqaGUyZy9ZcnlYSGM4ZE5aSEpyMUxLbG1mdUoxM0MxQ2ZEdlNa?= =?utf-8?B?MHdla1FUYXV4RmdVZTFPdkNoN3lNcVZXVFdMcCtVeGtUbnhwZUx5aEJrMklH?= =?utf-8?B?NWFiczhwRG1LM2JOQXdtQ3RmV3J6ZTFwYUhlaWt1SmdaSFFHMm9OMXVGSm5H?= =?utf-8?B?YmppdmZsZS9oWGJ4WTA3SGVWdEFsM3o3SGhpdXNsZVJ5QnkvTTdTZW5ZUUlI?= =?utf-8?B?Q2RlSHdOd3pKZis1NHhlNXd3Kytub3RKL01yZHhmby91VzhndnNOTU1LZlAx?= =?utf-8?B?ajVBeWp4LzZmanIrQ2s3SmtneHdwREN4c3JKeHVhK0syY0Z2UWpnODlhdVc2?= =?utf-8?B?MCtUWDhJbmh5YXZsaGpxK09hRWY4TFl3SWxSWW9BdjU2U01lVFlySFNmalNQ?= =?utf-8?B?RE9nVnJzTDQvdXlqcHo0MWpUZk4rNHd4UFppVGJ1Sm95OUNkMzZpKzNNN25q?= =?utf-8?B?NjM2TkkrUXBwNlZhb2hPSzVwWXgyNTlBM3JaZWJGVWRhbUxsRlBDWXFEVHdv?= =?utf-8?B?Qm8rWGFkUnRMSndJSHlubkd0M3VwYnpETXQySkdBNmE0bmR5U2pSeWhVNWFI?= =?utf-8?B?K2RjOUlQNk9wV0k4VHZBTGlwQ1B1c1IvLzYrZlpKWUVoMGJwN1hZNWRTK0NP?= =?utf-8?B?dGNVaDFRS1dCQ2s3bmRIZlFKSFFPdmJZMHVSUUZNc0FNRW84WnJXbHY1VzdE?= =?utf-8?B?OEtaaDJ4SDhRM2s1c0R0UGdDbG1MZjJKNU00Z1B3YjdKaGMrbDJ4enlCWnRL?= =?utf-8?B?bUs0UnFDUndJSjBJUkVHUjRQdVlzanRZRDQrS1JEV3hvNlk1SWhrcU1ZTzhI?= =?utf-8?B?bTB2Z1RKTmUyUE9Da016VElaREdIczRMNjhtTEQ4MUcvWG4rTHFRMXY3b1RU?= =?utf-8?B?MlZjZ0lPMEpHcllqcGlacHhTVVV6WVdLNG5kb21rbHZ0VnNBSERlQ3g2Y1lO?= =?utf-8?B?SU04UU0wNVE0VjlRYmZ1bThTMWlINTZQODhydUhFVVFpdUNobnQwUmhDV0l0?= =?utf-8?B?UlZzK1N4cGc1WVBOZ2JYVWJta1k5S0FtUy9pa21WRFFKM0REdTlnVXBmbFlT?= =?utf-8?B?ek94UTNNYUxJbzVYQjVHQWdZRVJzQzBMcHV0OE1ldmsySEFJYjAvZUZRQW40?= =?utf-8?B?UmdiRTYxR0F4UFNjK0ZsRHdEYUZEb1ZHQStkbVVTeldDUndUc1pmS1phVFlC?= =?utf-8?B?d3JybVV3K0J3SmJxWGtmemJQL1gyT3RnNVlVL2V3SlNvZmJXdWloV1ZoTEYx?= =?utf-8?B?MUwydWJKRjhuNkJINkQ1a2RuVFJGWHV3ZDVKVjRsWFZQVDFZeWV2eVFUdGpB?= =?utf-8?B?N0QyNzhoRk1QbG5jZTVSc01YZUxqWTc2aVdPa0pDdHFuMmJxN0RaaHJicHhZ?= =?utf-8?B?d1pCOWs3QVlINzBvZ2poN1F6a041Vlpna2h5bkM2UDBNR3BHUXRHcGo2U3Nl?= =?utf-8?B?TWZzUzYrRy8rNjdBdEI5L1ZvWUVFZ2pNbHJuT1lpY2J5UkN2U3owRC9SWkVi?= =?utf-8?B?NFBXRFNtcGdEZGR6cFRUQm5VMlZ2WHJQT1BTK1JTUEtpb1Z4aHpLTGJJMUdT?= =?utf-8?B?NGJaSFNXUFhrMXlNaTJWZ3ZDclpKR2U3Tk10Z1VyWHhwRlh1SURURCtVaFNO?= =?utf-8?Q?yK5S0q?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(1800799024)(82310400026)(36860700013)(376014)(7416014);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Jul 2025 22:55:59.3962 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: e4d62f4c-3cb1-41ed-35c1-08ddc3f2c408 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=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CY4PEPF0000EDD4.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB5830 On Tue, Jul 15, 2025 at 06:20:09AM -0700, Vishal Annapurve wrote: > On Thu, Jun 12, 2025 at 5:56 PM Michael Roth wrote: > > > > When guest_memfd is used for both shared/private memory, converting > > pages to shared may require kvm_arch_gmem_invalidate() to be issued to > > return the pages to an architecturally-defined "shared" state if the > > pages were previously allocated and transitioned to a private state via > > kvm_arch_gmem_prepare(). > > > > Handle this by issuing the appropriate kvm_arch_gmem_invalidate() calls > > when converting ranges in the filemap to a shared state. > > > > Signed-off-by: Michael Roth > > --- > > virt/kvm/guest_memfd.c | 22 ++++++++++++++++++++++ > > 1 file changed, 22 insertions(+) > > > > diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c > > index b77cdccd340e..f27e1f3962bb 100644 > > --- a/virt/kvm/guest_memfd.c > > +++ b/virt/kvm/guest_memfd.c > > @@ -203,6 +203,28 @@ static int kvm_gmem_shareability_apply(struct inode *inode, > > struct maple_tree *mt; > > > > mt = &kvm_gmem_private(inode)->shareability; > > + > > + /* > > + * If a folio has been allocated then it was possibly in a private > > + * state prior to conversion. Ensure arch invalidations are issued > > + * to return the folio to a normal/shared state as defined by the > > + * architecture before tracking it as shared in gmem. > > + */ > > + if (m == SHAREABILITY_ALL) { > > + pgoff_t idx; > > + > > + for (idx = work->start; idx < work->start + work->nr_pages; idx++) { > > It is redundant to enter this loop for VM variants that don't need > this loop e.g. for pKVM/TDX. I think KVM can dictate a set of rules > (based on VM type) that guest_memfd will follow for memory management > when it's created, e.g. something like: > 1) needs pfn invalidation > 2) needs zeroing on shared faults > 3) needs zeroing on allocation Makes sense. Maybe internal/reserved GUEST_MEMFD_FLAG_*'s that can be passed to kvm_gmem_create()? -Mike > > > + struct folio *folio = filemap_lock_folio(inode->i_mapping, idx); > > + > > + if (!IS_ERR(folio)) { > > + kvm_arch_gmem_invalidate(folio_pfn(folio), > > + folio_pfn(folio) + folio_nr_pages(folio)); > > + folio_unlock(folio); > > + folio_put(folio); > > + } > > + } > > + } > > + > > return kvm_gmem_shareability_store(mt, work->start, work->nr_pages, m); > > } > > > > -- > > 2.25.1 > >