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 82236C43334 for ; Fri, 8 Jul 2022 15:59:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 17FB86B0073; Fri, 8 Jul 2022 11:59:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 12FC46B0074; Fri, 8 Jul 2022 11:59:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EC4BA8E0001; Fri, 8 Jul 2022 11:59:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id DB6026B0073 for ; Fri, 8 Jul 2022 11:59:38 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id B5D4720894 for ; Fri, 8 Jul 2022 15:59:38 +0000 (UTC) X-FDA: 79664392836.08.B8BB91B Received: from NAM10-MW2-obe.outbound.protection.outlook.com (mail-mw2nam10on2074.outbound.protection.outlook.com [40.107.94.74]) by imf28.hostedemail.com (Postfix) with ESMTP id 101EAC0062 for ; Fri, 8 Jul 2022 15:59:37 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Z7pcE+KZHdkhtQ7PT1mMHpqO3ao872eS4H3ZqPji6tdlk9Qit1+5h2uxsB+wlDau7esYOxR0LqIBCayBbuH1wBVeo2NUbu9I/WvYT/S8eAdRlq1g84oiQph6tARsPwSpiyuw3TfZVWez9+f1NBRVLmej8D8wuqfJytHRodtwpGcIUv95k4XQBPUXDr+CTZwdKQfuB279h54Q8fQW/07OY1vy4CxR/szAYwLoSCiQWPZ92piigbzfD9c+q8FMO9d8RUIwQRBhwm9MEhx5JOpiSNLmQKyizCtqR93+2Tq2MfqeZ70ggp/4cb9tTFTOk8c64mkddygPpo/ypQlLUf/fOw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; 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=FyjnSQWr2k9z5kjq65GVeHkHLKSloVmqtsse6GTKAd8=; b=Ckf57/YvtuvdN/yrQUfDBk5+WULyYy1oUuK4ddw9GO4wJqhSLZbQkubEaiWIbOqKip/9oScYi3FQgNo6EUsEAEeHcXcYr3MaR35zeBHqxo+bvFhPpz2KwYaZKPds+B/2NbYWViB/SPHegopzIdKVD7DmSXqUTBccjFazI8KkB8Cpfc1SRkjcsHZa3Uj3WL1LE5LJLCp57eHQDVcuQdr5Q5jzUohqFTKd5nH/KzqeM4cKIf1X4AcVBXmZc6lr1klzf/pEP+o0Qx/9gSwXfsCRKAwNmo6y84yAhmccR13cQQ0AK8ZXn1Vi1NywIT6vAIGHBNp4PahHshCvEhHACVUZrw== 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=FyjnSQWr2k9z5kjq65GVeHkHLKSloVmqtsse6GTKAd8=; b=Ra07olvB72sqnjAYtxqyorjxa598yzCHeNoFgvI8qaPXSkidx+xVk+spaFHLNYXoyRUB2CrV7nAhMBQo5fzCFyvAAYe+sPUPZs1AE4k+65ax6F9j42a7C/WJcquY4TiEwEBtEflZkPXSLhk7/33D6JbmsvQKkgwCyPGMBNya6jY= Received: from SN6PR12MB2767.namprd12.prod.outlook.com (2603:10b6:805:75::23) by SJ1PR12MB6218.namprd12.prod.outlook.com (2603:10b6:a03:457::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5417.16; Fri, 8 Jul 2022 15:59:34 +0000 Received: from SN6PR12MB2767.namprd12.prod.outlook.com ([fe80::8953:6baa:97bb:a15d]) by SN6PR12MB2767.namprd12.prod.outlook.com ([fe80::8953:6baa:97bb:a15d%7]) with mapi id 15.20.5417.016; Fri, 8 Jul 2022 15:59:33 +0000 From: "Kalra, Ashish" To: Peter Gonda CC: the arch/x86 maintainers , LKML , kvm list , "linux-coco@lists.linux.dev" , "linux-mm@kvack.org" , Linux Crypto Mailing List , Thomas Gleixner , Ingo Molnar , Joerg Roedel , "Lendacky, Thomas" , "H. Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , Dov Murik , Tobin Feldman-Fitzthum , Borislav Petkov , "Roth, Michael" , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , Tony Luck , Marc Orr , Sathyanarayanan Kuppuswamy , Alper Gun , "Dr. David Alan Gilbert" , "jarkko@kernel.org" Subject: RE: [PATCH Part2 v6 35/49] KVM: SVM: Remove the long-lived GHCB host map Thread-Topic: [PATCH Part2 v6 35/49] KVM: SVM: Remove the long-lived GHCB host map Thread-Index: AQHYh9zZ2YXyQRnTe0iEslSS4jvfv61e+v3wgBRvg4CAAAHU4IABSe8AgAAAYBA= Date: Fri, 8 Jul 2022 15:59:33 +0000 Message-ID: References: <7845d453af6344d0b156493eb4555399aad78615.1655761627.git.ashish.kalra@amd.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: msip_labels: MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_Enabled=true; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_SetDate=2022-07-08T15:55:44Z; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_Method=Standard; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_Name=General; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_SiteId=3dd8961f-e488-4e60-8e11-a82d994e183d; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_ActionId=9f786f9e-54cd-4090-aa6d-7a1f5dc9f53b; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_ContentBits=1 msip_label_4342314e-0df4-4b58-84bf-38bed6170a0f_enabled: true msip_label_4342314e-0df4-4b58-84bf-38bed6170a0f_setdate: 2022-07-08T15:59:31Z msip_label_4342314e-0df4-4b58-84bf-38bed6170a0f_method: Standard msip_label_4342314e-0df4-4b58-84bf-38bed6170a0f_name: General msip_label_4342314e-0df4-4b58-84bf-38bed6170a0f_siteid: 3dd8961f-e488-4e60-8e11-a82d994e183d msip_label_4342314e-0df4-4b58-84bf-38bed6170a0f_actionid: e392fd9b-9141-4d66-8917-d4877bc36f3c msip_label_4342314e-0df4-4b58-84bf-38bed6170a0f_contentbits: 0 x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 6dfe6dac-94e2-4fcf-fbb6-08da60fad9c7 x-ms-traffictypediagnostic: SJ1PR12MB6218:EE_ x-ms-exchange-senderadcheck: 1 x-ms-exchange-antispam-relay: 0 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: 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 x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SN6PR12MB2767.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230016)(4636009)(39860400002)(346002)(396003)(376002)(366004)(136003)(84040400005)(5660300002)(478600001)(86362001)(7406005)(8936002)(26005)(38070700005)(52536014)(76116006)(6506007)(7696005)(38100700002)(33656002)(2906002)(41300700001)(7416002)(9686003)(71200400001)(55016003)(122000001)(186003)(54906003)(66946007)(66476007)(66556008)(6916009)(966005)(64756008)(4326008)(8676002)(83380400001)(45080400002)(316002)(66446008);DIR:OUT;SFP:1101; x-ms-exchange-antispam-messagedata-chunkcount: 1 x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?mwXl3DTvohucRDv+T04ZtEuxoxfkL+UPMkNKAR7SyDpOEkWjtHLZOsRahhlI?= =?us-ascii?Q?WN1341AId2fT7h7i8doBAKmAYBBH0piVDerbSBfP14Aw3+1kA6hLfTCCURaI?= =?us-ascii?Q?Iojz3twh+1mwTFF07YBiWExFwr9Tqf3RDPde4ptKW45UWUEhgGHSxzQE4Ifo?= =?us-ascii?Q?HCS9p17TswYaD+XqpsuFKlh7heHp2aTOSpZEajzEshdYNcpf4KJrCGWfbl3B?= =?us-ascii?Q?ecrAKx8yUQZPAD2qmO4O4oTUEdJnLF+9/j72edVSDAY1NMZqYbdJovmpn9Ii?= =?us-ascii?Q?pZQMDdMtzM6oRGhIIVVElUTGuCUjjePXAdm3pDaMVR7vo6TcrodmByio4zar?= =?us-ascii?Q?KIOUl7Yg1W0uWl/0+iz4jF7wJIgpsZsM7IsS7D54BT41bV9w72Tdwdem8r4g?= =?us-ascii?Q?0u33aHTsSpjgIc3jHOUpiiXreKG+aHDgE2GWmslBJ0WNsF03h66uEXuPY8vI?= =?us-ascii?Q?xuQXwQyARvicr5801jFUG6VVpstvVjnY5LmtATDDTvUmi8p18/viL/oOA44I?= =?us-ascii?Q?76WDxWW8Pbr14t24yCcxm7pgFyjRQ34LqfJU9EhjTJo4fU21KNLCMWTHXxI3?= =?us-ascii?Q?SXMwv9rws03Hl3a8b8JQKEkL6zC3T5D7bL9PmNgfGQeuTE7msGA69n4xC0IX?= =?us-ascii?Q?ZMiOZBuELT5K1vDdScmDQtoacYDn/78/qvEHFDzrELOK/vZTl3jAj7fhiV0J?= =?us-ascii?Q?7Br6BhqQmzcjvuKc5ruoGQNyPt3FV7j4i5fyr3oAuhlDrGjalAofbcTx8Tdl?= =?us-ascii?Q?StciojVZwvzCI6mCjuNDb8wOL9HO1WjI8qqfKPfvsbbogGoZi+q58O5z/UMi?= =?us-ascii?Q?n+7uS+PptdJSYdInKkM2b66wlxmdIoxfsYyIofFckQIzGcgqpqVy6C32zYmQ?= =?us-ascii?Q?/sBdc2P/1f4wIqFe+hLmPWNk+7sdR/J99iAMMirAFQD9S5uQY54KyS3vVEs5?= =?us-ascii?Q?+t1DGz9r12IfIznnbJU0/Otush6zErouYKK4wOTSZx62ES1Tomo1eNOhtIcP?= =?us-ascii?Q?GSsaEoKYUoHkd+RGazrbJqphDDxqWL+49bcDKupLRYJp6ChyywhVuGZR1UQs?= =?us-ascii?Q?YPgcR3SqqvQO/vH9qZmi8NSzAQsz9Z+W0qsl5L7PZnW67Y+7cm1pr24awjja?= =?us-ascii?Q?rNOTHr0dMEMg2lTgshqA2gICkOMP0z44ma5vGB82V1tsxv95XdbFeQEVgIS1?= =?us-ascii?Q?HTz3b72l46jUTsFCrB1kLSl14oLc2zQKOQ6OR1/Y9qjCoQKCM1FFh+E1lijy?= =?us-ascii?Q?SDtYKMR31JZp5Bw1fvKmVEzjkbP+MXWZzUQTtZ2mcWHVV20oNsr8KkDHjEt4?= =?us-ascii?Q?TJYuIESwjss2N/sKunTlvMMXisEvVPIWWrF1iiN+ROIC4oUCyYfhQsyk4qbq?= =?us-ascii?Q?lvYDv9mz01FwU8Vpuh2cOrXAs7MxqoRLAWGyirF5E5PXkAi7oDKyKJFiWFDi?= =?us-ascii?Q?D8omHrPr+IV0SyIYgHGpMS5WtZnVSJrcgHBNkgL7VNcl3hccysmOERNVCZvh?= =?us-ascii?Q?hoYVQu1LvhFoOoiH0HGKWkzldZNHzx4EXoXxG5tfVugibKPp1LQJplz1omMq?= =?us-ascii?Q?UQOd9wWcNAYLZKD+2m8=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: SN6PR12MB2767.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 6dfe6dac-94e2-4fcf-fbb6-08da60fad9c7 X-MS-Exchange-CrossTenant-originalarrivaltime: 08 Jul 2022 15:59:33.7730 (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: RraS8h700ljUnzmA6aqfdQ2s+MdjRHgcumP/9mDAGqiG/J0p5JvA6Cx0/00wwZwnHGDmLKGCLXhzL8wBWPj47Q== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ1PR12MB6218 ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1657295978; a=rsa-sha256; cv=pass; b=S5prEsVJZtTv0lqdyuIgztc3Z8exE7wfVfa7N00uRxRaPe/Lqg5lLLk42Uk8jMsl04qvnv rn+cOwTR1bVu/lKrFa7NlMutEqd/ikV99tWmEXxjfENpYwH5CwNELQrdj1ya2WZAbjXeR3 Sjon3V7vEwoNSTk4ZPtsYCOyYZzK3yA= ARC-Authentication-Results: i=2; imf28.hostedemail.com; dkim=pass header.d=amd.com header.s=selector1 header.b=Ra07olvB; spf=pass (imf28.hostedemail.com: domain of Ashish.Kalra@amd.com designates 40.107.94.74 as permitted sender) smtp.mailfrom=Ashish.Kalra@amd.com; arc=pass ("microsoft.com:s=arcselector9901:i=1"); 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=1657295978; 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=FyjnSQWr2k9z5kjq65GVeHkHLKSloVmqtsse6GTKAd8=; b=TNI4nPrELQtgWhLAA4HtOE/Cno9BX7kF5RtIjGeW/w/BMJIFEOCIgYAaFa4vKruYP8T6H3 inpkWYBxuldHxEWwch2kxZYNz8XWEq6C+jn0kHKpTdDrUbvZ+UDF1HU3Np8DaOcAFHOlgl xzlLz8Pp+L6EPlZvZZ8hXFt3hP2d5mA= X-Stat-Signature: q1dribb3h3w8qw5fgrewxqguwnmcqgtq X-Rspamd-Queue-Id: 101EAC0062 Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=amd.com header.s=selector1 header.b=Ra07olvB; spf=pass (imf28.hostedemail.com: domain of Ashish.Kalra@amd.com designates 40.107.94.74 as permitted sender) smtp.mailfrom=Ashish.Kalra@amd.com; arc=pass ("microsoft.com:s=arcselector9901:i=1"); dmarc=pass (policy=quarantine) header.from=amd.com X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1657295977-207265 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: [AMD Official Use Only - General] Hello Peter, >> > I don't see anything mechanism for this patch to add the page state ch= ange protection discussed. Can't another vCPU still convert the GHCB to pri= vate? >> >> We do have the protections for GHCB getting mapped to private=20 >> specifically, there are new post_{map|unmap}_gfn functions added to veri= fy if it is safe to map GHCB pages. There is a PSC spinlock added which pro= tects again page state change for these mapped pages. >> Below is the reference to this patch: >> https://nam11.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2Flore >> .kernel.org%2Flkml%2Fcover.1655761627.git.ashish.kalra%40amd.com%2FT%2 >> F%23mafcaac7296eb9a92c0ea58730dbd3ca47a8e0756&data=3D05%7C01%7CAshis >> h.Kalra%40amd.com%7C647218cdb2a040bf354e08da60fa2968%7C3dd8961fe4884e6 >> 08e11a82d994e183d%7C0%7C0%7C637928924845082803%7CUnknown%7CTWFpbGZsb3d >> 8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C >> 3000%7C%7C%7C&sdata=3Dss8%2F5qualccXQero9phARIG2wvYhtp8SMdve3GglZeU% >> 3D&reserved=3D0 >> >> But do note that there is protection only for GHCB pages and there is=20 >> a need to add generic post_{map,unmap}_gfn() ops that can be used to ver= ify that it's safe to map a given guest page in the hypervisor. This is a T= ODO right now and probably this is something which UPM can address more cle= anly. >Thank you Ashish. I had missed that. >Can you help me understand why its OK to use kvm_write_guest() for the >|snp_certs_data| inside of snp_handle_ext_guest_request() in patch >42/49? I would have thought we'd have the same 2M vs 4K mapping issues. Preemption is not disabled there, hence the RMP page fault handler can do the split of 2M to 4K on host pages without any issues. Thanks, Ashish