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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44A2FC00140 for ; Mon, 15 Aug 2022 10:12:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231393AbiHOKM1 (ORCPT ); Mon, 15 Aug 2022 06:12:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231539AbiHOKMC (ORCPT ); Mon, 15 Aug 2022 06:12:02 -0400 Received: from NAM10-DM6-obe.outbound.protection.outlook.com (mail-dm6nam10on2040.outbound.protection.outlook.com [40.107.93.40]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C3EB140EE; Mon, 15 Aug 2022 03:12:00 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=PpLg0rsFmKM7VFh23UmJBWRKIh5xY08pqwfpHN23eQ7+EDZtk0Y+74HXPcfc0OXYGKYZlD5qIuNrxwvWaigOHzY5o3dIcOVJMEMrWudVQD4WAIoQNmaumi/lqwk+iK1sjOaDQLu4MSY2l7zDMjGunXNNaEzVpWdzXS/WS58ZfWP/5ofT05BXy6vVmHD+m/5YPQ9HZIiBx0dypIgdLEVoRDh5zXSELHOw/z2xeXBz4mnYljW/l63zwwPHCgcUxsfFRmoOIx8sYKiv7HtdWD29zIEvTpiK2s4qr5e/nZznE/E/UERhsjstwtke4wWcu0q6SRmlmlAIDrklKMR3zolcTA== 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=inBftJlKOMmZecCK/n1gTNUguOSc1CLw7dOvEg19/Pg=; b=NcoTxid62cmoD266XwIYPFBLF8tILBiBIaIJm1vky1tTUgJFKGgy30We1ImudjmwagLv+EDUdcE+EZ/lUQoNyfCfqKqcIPPOxL4jL1GorXHOi9yBshnHCFNfJf9rrA/LiyLmPOakk0JZgbudcxJOGmNJKXQip8gHn6TaE1rbcY/3VJe4MejYHbe/NAFvne6AEIw6/YOmCqlm4VysL3Q0fUxBfaWp5rnQM6Levk7TfpU/pRfKZdxv0CXmbhwZ0f/sg2M5CyVearA6EV14Lbc3Qieew977NOrwzLrk9hqvguhHNjf+NlfjXVwRQG0RCDqQhq61g9ReXcsEX74AaN5wBA== 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=inBftJlKOMmZecCK/n1gTNUguOSc1CLw7dOvEg19/Pg=; b=3zw4PBaMbwgJ3G/LLZ1RRtJiNsEB0tzlMhit4ylwMnjoEri/eJ+Njo+IK4jY9+HYQ4iQ1He4Jo4frdvOfjl+1QXImOqGCW4fGua5Q3bZi7FkamA6SErbVBxUNu4I3lGX/MLa1XWlMXck1hbgx6ZPIZ71soTK/aU/Bpta9Dn0xcM= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from BN8PR12MB3587.namprd12.prod.outlook.com (2603:10b6:408:43::13) by DM6PR12MB4251.namprd12.prod.outlook.com (2603:10b6:5:21e::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5525.10; Mon, 15 Aug 2022 10:11:58 +0000 Received: from BN8PR12MB3587.namprd12.prod.outlook.com ([fe80::905:1701:3b51:7e39]) by BN8PR12MB3587.namprd12.prod.outlook.com ([fe80::905:1701:3b51:7e39%2]) with mapi id 15.20.5504.020; Mon, 15 Aug 2022 10:11:58 +0000 Message-ID: <8caf3008-dcf3-985a-631e-e019b277c6f0@amd.com> Date: Mon, 15 Aug 2022 12:11:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH v1] drm/ttm: Refcount allocated tail pages Content-Language: en-US To: Dmitry Osipenko , David Airlie , Huang Rui , Daniel Vetter , Trigger Huang , Gert Wollny , Antonio Caggiano Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Dmitry Osipenko , kvm@vger.kernel.org, kernel@collabora.com, virtualization@lists.linux-foundation.org References: <20220815095423.11131-1-dmitry.osipenko@collabora.com> <8230a356-be38-f228-4a8e-95124e8e8db6@amd.com> <134bce02-58d6-8553-bb73-42dfda18a595@collabora.com> From: =?UTF-8?Q?Christian_K=c3=b6nig?= In-Reply-To: <134bce02-58d6-8553-bb73-42dfda18a595@collabora.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: AM5PR1001CA0059.EURPRD10.PROD.OUTLOOK.COM (2603:10a6:206:15::36) To BN8PR12MB3587.namprd12.prod.outlook.com (2603:10b6:408:43::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 2408e371-ee95-4125-1e74-08da7ea69670 X-MS-TrafficTypeDiagnostic: DM6PR12MB4251:EE_ X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: KJd+JUXroGqBlZeIjxVJPR0fYPhp+jCxlNu5ZuzHzCPQqWHm+thcrc9fLoJJB6LAY3mcck7S8tEm/5GBm0x7edn9Wld8BQa7lT7m3A534By3T/d/D8sXApqgU29FMQu84XHNSeaF+6T5DmLEvQl2cd/dchuMRpJLUsgDtWd1QvAmqQa13AHN9Riw4cu5VdEwgKYhl+f44hwIO86/qtz42J5hU2WjWX3xjqxeJ3GFry2Fxq5AXInDMa7S/boNcSs5c5pmFxzYGfrbNxABOxbzfk330O7C0ZAAvgevaVaN98yg32S07ZKTAZTorNXamJlCYzSVKz+0h6tdRBdDhS977HOvQYLm3CcZyGGGVfoEMdBMVAg1d3nvc8io+MhhA91MOFiIPg+tsTAYTbmnmZdHJ54z6pR5JfMgSHcUQKk1L4R/TtglIXTliuMYNFwUwyHrenn8XCUYQXaV3BJBjtM02R9atwQ6pjY/tHNiJNOCnQz+Y/1id++1pEFW2Cb8e7aGHfEBdaFDaOAVHr/3bEB+ia0Vi6e0N2LqPNyYHuXs+gmq0LxAWA4t3mZsKSZLkRIHpxhAAxXyVbNkwy5skyYjkAUUuivl3YwA4xE5uVPDDxTUsvBYa5cQoLbkmhhyCgHRoVXaK/OgA3+4qQ31tRTONL+kTwmj1VrTW5jr9JrCuFIqNCMzht9izWhSjWf7EyXobuMrDmk0Fs7tyWHaiBy8lGKPnSXz/bwH/ivS8QqMMKtci5Sr9Jb+OcrV/MFbInfmp7siuSjxs0h8TM4eFxss4nIUYjOcLP9oGCMfCKXeMbDwnmqSMEFX84zEcrC4sKHIc+lyTMhBjfRxUkS+M6wGLQ== X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BN8PR12MB3587.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230016)(4636009)(396003)(346002)(136003)(366004)(39860400002)(376002)(7416002)(8936002)(5660300002)(31696002)(2906002)(86362001)(41300700001)(66476007)(66574015)(186003)(6666004)(2616005)(6506007)(6512007)(83380400001)(478600001)(53546011)(38100700002)(66556008)(4326008)(8676002)(316002)(110136005)(6486002)(36756003)(66946007)(31686004)(43740500002)(45980500001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?WnNzaThMU0owZUY1bGFHVjdzbEpvNGVQUDlrYytJS2x0dDNiSmQ5dlUxODMz?= =?utf-8?B?UU5kTWtaZ2Z5OUllRlRwVStCZXJkcE5kOHo2ajNsayt2ZTE3amd0ZUZ1elJs?= =?utf-8?B?eEttVy9EWTNlTWpPM3JBSEhKcU5IaDVpdHkyLzlOZEdwMDFweEtZbUFsR2F6?= =?utf-8?B?eWlqaVM0UXNabngxTnVMV3lQc05ZalRvWTZZbTJYVVBwbW5pQXM1YnJaaTZU?= =?utf-8?B?TFdmVSsvT1dwSVNYMG1DbVlubUNtdnU2dGhObFVSSTJkcXh6RkZJTGZQOFl2?= =?utf-8?B?Zi9mSWcxS2R2MUswbldONFNlcnlVcERmM1RZa3FMSjFZdThRZVA2VkN3TFpK?= =?utf-8?B?UGIrenBMU3dpbis4VFV3djRXaGhNSnovSEJlSVFzR1lMT2VscHhIbTU3RGNL?= =?utf-8?B?SW1iU1FVQkswTytHZHdtdEZ1TFhySmdmTy8wUjdHQ29pRmh6aEs4TzJyNEc0?= =?utf-8?B?UDFEREx2c1FDUW1KZ2EzdXlIS0U4ZTA3MEEwOFFqMmhkZU1vN2VoK1dDR0Uv?= =?utf-8?B?cEJWYWd2M0xxRGdSSUtoMi96TUxFS3RuRVYyWHBiZndTOFV5K3NDU24zZTls?= =?utf-8?B?YWpqRDVsT1puZDNBS1ZKTFFWVWZ6L1pTMU9OQlVhQ1BXeENzTCsxaXRYZUhy?= =?utf-8?B?YURtL2FWd2NYbTBvSy94QTA5ZlhwZ3NMKzRXVFJFL2NkbUJKOExpd1FUSkhs?= =?utf-8?B?dFRBZXFEYWxuV2x2bXRuRU52eGE1RExRdG00bWVRYnFOQWRsb0U4OUlqR0Zq?= =?utf-8?B?M0NTOGVqU09kTlBEeTBJNXowOFBQN2Z5cnRvb1d3R2xaWjl5MG5XZ2JZcDYy?= =?utf-8?B?ZTlZeThlZFh3YXFTSGVGTmo3VTRCK2RnYVlvMS9mdkgrcHhzMStVSmVXeVJT?= =?utf-8?B?WFZDMUw2RUhPYk9ZQThIOStUbzdRYXRsUmZiZnRaRG83c01yQjRpYUtjQ1lF?= =?utf-8?B?YlF3OGVtSDkvNkFPcUlSS3Rzekk4MVkvSlRQTHg2MUZBRWw2VG50TGdMUmdD?= =?utf-8?B?WWgrZ3JrYzE4dnJKVXVqU01rQ2lmTFpmTlFVSGNYUEw5Mk5oRnZtTHhIMnVN?= =?utf-8?B?dmwvQmVMTHNjTXMxQUwwUENDY2dNK3FRNC9VZld3dC9DaG84SHYvTFh6Q2Nm?= =?utf-8?B?MWptSWN4akMzT2dNdll5WlIxYlFHcDhlVmd4WnNFRmg3WmRGS09ieW4vUFho?= =?utf-8?B?dnhyRldWZUtDSXd4VE1xK3pOY2tQanl6bFZ4enpGU1FMZXlRYlJGTnd6blVn?= =?utf-8?B?Vk92bzJ3NmlOM2JzUTdCWWlZSnhsYzRTWHRBRURaU3VnbmVrcnpyWElVZkZs?= =?utf-8?B?UTRrdHQ5d0tNYldmdWdWSkxCaEI4SXZrQkxQMHg4c1JXYUNyNUZGZi96WTQ2?= =?utf-8?B?R0dJSC9XUXhYU1ROT01IcnJodXFjb21mQUttdXdiay9LenlSeUczdFJhajN1?= =?utf-8?B?YkRUR2U3WTgwODRTclVsdkpNZmNIVzBPU25DSGNjVW5yT2FER3Zyd0Noby9z?= =?utf-8?B?emFDMlVoWGpJS0FndnRqazBYOGRublhaYy9aQjBoWVlRelhnZGJYbTBsNWdy?= =?utf-8?B?b2JMNHpld01vdDc0dzljaWlIRjVZc2dPaGhYUnVlZmRmR2lMZEVKelRVbmE0?= =?utf-8?B?bUZITUdlMGM0UVhGbE0vcFRvQkVUMEluZi9oNXpiWk05N011T3NNRTVPcHVH?= =?utf-8?B?YktDRmNybDMrM2pwYktPNjIyMUVyamZ1MEg3T2Y2NGoybkpOM3dVcnJmcCtM?= =?utf-8?B?WnhUSEVaaXk1T0dDdWljemJ3Z1lrekpDbE1leHVpNFozM2FnUDNIOUMvNC9I?= =?utf-8?B?ME9QN2F2cGhESS9udXZUdUkxRDFKYk1Ba1M3RXFTOUdFakt4bFZ6Qlo5TlRD?= =?utf-8?B?WUQyYkVSbFFPY3pYQ1l0VWJqcXJ1V1VXM0xxekwrWnB0Tk85YzNmUGZGSGEy?= =?utf-8?B?aFk1Rm81ZE5SaCtFMEMwVHdVeDArcVZiQVpzYkJGcUxZOTA5WVBSQ1Noc2Y3?= =?utf-8?B?ZjNhU0RycExCdzIwSlFYd29OWXJJeXBHTC9qSW50cW5jRGZSOEFzZWJmSWNn?= =?utf-8?B?R3JLa0hMQit2Z2JnN1Fsc09PREJDZmJ3SU1jZSt1S2VCVXpIckNBQlZiSFln?= =?utf-8?B?dldyMXMzQi9GV3hLcXRiVXZ2ekxzY3ZUaXNYcWFJTnpYY3hDV3R6SE9rZkdv?= =?utf-8?Q?+69ZLcuRlrUWufC9ip5W/7DUSuVdid0ByDckCEpyuLbH?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2408e371-ee95-4125-1e74-08da7ea69670 X-MS-Exchange-CrossTenant-AuthSource: BN8PR12MB3587.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Aug 2022 10:11:58.3228 (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: /6amPt3rAAIocRnt1ujLPZAoo+tajaLJ5xsc78Onfu748jqehN/nS3KPOnH3F7i6 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB4251 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 15.08.22 um 12:09 schrieb Dmitry Osipenko: > On 8/15/22 13:05, Christian König wrote: >> Am 15.08.22 um 11:54 schrieb Dmitry Osipenko: >>> Higher order pages allocated using alloc_pages() aren't refcounted and >>> they >>> need to be refcounted, otherwise it's impossible to map them by KVM. This >>> patch sets the refcount of the tail pages and fixes the KVM memory >>> mapping >>> faults. >>> >>> Without this change guest virgl driver can't map host buffers into guest >>> and can't provide OpenGL 4.5 profile support to the guest. The host >>> mappings are also needed for enabling the Venus driver using host GPU >>> drivers that are utilizing TTM. >>> >>> Based on a patch proposed by Trigger Huang. >> Well I can't count how often I have repeated this: This is an absolutely >> clear NAK! >> >> TTM pages are not reference counted in the first place and because of >> this giving them to virgl is illegal. > A? The first page is refcounted when allocated, the tail pages are not. No they aren't. The first page is just by coincident initialized with a refcount of 1. This refcount is completely ignored and not used at all. Incrementing the reference count and by this mapping the page into some other address space is illegal and corrupts the internal state tracking of TTM. >> Please immediately stop this completely broken approach. We have >> discussed this multiple times now. > Could you please give me a link to these discussions? Not of hand, please search the dri-devel list for similar patches. This was brought up multiple times now. Regards, Christian.