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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MSGID_FROM_MTA_HEADER,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BEDBC433ED for ; Fri, 14 May 2021 15:49:00 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 85F5F61444 for ; Fri, 14 May 2021 15:48:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 85F5F61444 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:51162 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lha3e-0002cB-MN for qemu-devel@archiver.kernel.org; Fri, 14 May 2021 11:48:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37274) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lhZWn-0007g2-5E for qemu-devel@nongnu.org; Fri, 14 May 2021 11:15:01 -0400 Received: from mx0b-00069f02.pphosted.com ([205.220.177.32]:21700) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lhZWh-0007To-Nd for qemu-devel@nongnu.org; Fri, 14 May 2021 11:15:00 -0400 Received: from pps.filterd (m0246631.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 14EFB3mN027579; Fri, 14 May 2021 15:14:51 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : subject : to : cc : references : message-id : date : in-reply-to : content-type : content-transfer-encoding : mime-version; s=corp-2020-01-29; bh=H8yAbF+2Dikv468pzSwylOW4SL3VBt2h1FEdQUjnp3w=; b=thhnb6MVm9Zco25V3GT/H42r3T7PS0ZsrSUsKJ2YPvkbv4E+WCnEaFs2+LnEEL56jHXk kR8BDQ02TjVenZyr75baaZtel3bD10XeUkeemQzinkErjWqHF9V7TcvBK8bdHUdg08Dv lQ4A5FD8CG6E8fb9jeHfBgii911qZi01OU81AuvBjsCPO8b2OfJP4kSDYkMc47RyWiyT QLU1R7NCGhg/JBk1Rmh1jErflLmPCo2tw1X0jscw0n57BSWM3E24stC/U/cxFUAkORbb ttAWLhZO0jSQUEcOFqw5cjU9875JWdesQowQIsjlFX/uBW3xLiF6aCgzMefSE7HMvTXk dg== Received: from oracle.com (aserp3030.oracle.com [141.146.126.71]) by mx0b-00069f02.pphosted.com with ESMTP id 38gpqmgqjb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 14 May 2021 15:14:51 +0000 Received: from aserp3030.oracle.com (aserp3030.oracle.com [127.0.0.1]) by pps.podrdrct (8.16.0.36/8.16.0.36) with SMTP id 14EFEo0F014143; Fri, 14 May 2021 15:14:50 GMT Received: from nam10-mw2-obe.outbound.protection.outlook.com (mail-mw2nam10lp2104.outbound.protection.outlook.com [104.47.55.104]) by aserp3030.oracle.com with ESMTP id 38gppq6v0t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 14 May 2021 15:14:50 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=hk/5BxWdqlHjK0y1qfrWJ2p+/0TiepTVFkdUTMOwKDdsxmI1dqipGM+poiB9stGnOcLqdVdSPEIuZuXi3t1we/MteLL7Anxcu3yOoEgzJe0pEQ3dolcpM9tyFssD9AlMPKu9KWdwh1X21CVFsKS4XmCXaNgyaq8c63quCAod2/viRlVm56jVh5jWkzsxbkoee65pnB4w4Bo40d6Qxt9rhh79lBmk4QgAasWjF4vJ/fb3RvLJA9O4NvIZsVTGea5eLwT83c1kl0KjU0UGpOJ2Xaoj9Lp6xWnRwfhVWApRKzp8ozM+WaK31SkdgETp9TfvKzVUgsZgAnLvWEQpCGtyXA== 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-SenderADCheck; bh=H8yAbF+2Dikv468pzSwylOW4SL3VBt2h1FEdQUjnp3w=; b=AyEJYlmKwwJDdPMzw+E4e9y5AxnmUoTwCErX+cEu26aAKR/YxMSWwnWLVaaiE1k4pHYh1sIsicqXak1VixgAOQ7tSGx9fZEvke09w/X+NWuKKuuSOFJHFqRzwi/lsaar0wzT7dlRiFA36hS7ApbrFd7Y83s3GZf9RuaspCruZU3uvQvYDpE04J51FfAuYOA9SyFwLJ/u6rM4kBuZaTUmuHvRB02eFEIoP5wc4M3KkAJP0eO3ufRWmppUF4r9U4CCQMWVkBF6ZCD8X3Z/ZvpcIgbe3sBWoplfBd19e3rgBVGxbacx82XbGOl8tYYzOs3gNaWzbXRJ3lFur9AwBLOeGg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=H8yAbF+2Dikv468pzSwylOW4SL3VBt2h1FEdQUjnp3w=; b=RNtR6+gWkJ7f2oz1atGgQsGxfMqF096DscMmRzmrw0TSJ4t+7S4ELL5EHzz1rqsUBO0/SgrIzWr6GGiq/WgAVESLEtNHkZKvwnU7mURwiKEL/pNnTg4ZsR5D5pVywI7LacqPJxAqFeYqS0qylWRPlfrPrD69gFCUh2Tlk29zb2I= Authentication-Results: oracle.com; dkim=none (message not signed) header.d=none;oracle.com; dmarc=none action=none header.from=oracle.com; Received: from BYAPR10MB3240.namprd10.prod.outlook.com (2603:10b6:a03:155::17) by SJ0PR10MB4461.namprd10.prod.outlook.com (2603:10b6:a03:2d8::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4129.26; Fri, 14 May 2021 15:14:48 +0000 Received: from BYAPR10MB3240.namprd10.prod.outlook.com ([fe80::6ce3:f0a3:c303:f851]) by BYAPR10MB3240.namprd10.prod.outlook.com ([fe80::6ce3:f0a3:c303:f851%7]) with mapi id 15.20.4129.028; Fri, 14 May 2021 15:14:48 +0000 From: Steven Sistare Subject: Re: [PATCH V3 07/22] cpr To: Stefan Hajnoczi References: <1620390320-301716-1-git-send-email-steven.sistare@oracle.com> <1620390320-301716-8-git-send-email-steven.sistare@oracle.com> <008ac3a4-a187-3e9f-d82d-8279e82805b1@oracle.com> Organization: Oracle Corporation Message-ID: <881e5c07-8582-478c-9c13-47b1967cd3da@oracle.com> Date: Fri, 14 May 2021 11:14:44 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [24.62.106.7] X-ClientProxiedBy: SN6PR05CA0021.namprd05.prod.outlook.com (2603:10b6:805:de::34) To BYAPR10MB3240.namprd10.prod.outlook.com (2603:10b6:a03:155::17) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.1.92] (24.62.106.7) by SN6PR05CA0021.namprd05.prod.outlook.com (2603:10b6:805:de::34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4150.11 via Frontend Transport; Fri, 14 May 2021 15:14:46 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 0763ea00-c3a8-45c5-586b-08d916eb03a9 X-MS-TrafficTypeDiagnostic: SJ0PR10MB4461: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:8882; X-MS-Exchange-SenderADCheck: 1 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:BYAPR10MB3240.namprd10.prod.outlook.com; PTR:; CAT:NONE; SFS:(366004)(31696002)(44832011)(6916009)(6486002)(36756003)(7416002)(5660300002)(83380400001)(186003)(54906003)(4326008)(8936002)(86362001)(31686004)(66556008)(66946007)(2616005)(956004)(498600001)(38100700002)(107886003)(16526019)(66476007)(8676002)(36916002)(26005)(53546011)(2906002)(16576012)(43740500002)(45980500001); DIR:OUT; SFP:1101; X-MS-Exchange-AntiSpam-MessageData: =?Windows-1252?Q?lrfNFESF4fKgyES9C1oXcE4SWJqtz1f+kT72PmB1eM59yCQwOKR5Bcxo?= =?Windows-1252?Q?o1mkA+uJI/verUIoGLJEAPy92kAohStSdqtyHoehdD301JROPuq6TfNW?= =?Windows-1252?Q?bCVaguHr4XOdkbqaOWMddYDtebIKbDvtiD5vvjtQf4lSfogKLqVjS44L?= =?Windows-1252?Q?4xg25nI3wdCH5mUvaGuUIr1rMG1U3N4ezlpTOBFnMlhaRDKblpKEkrQ7?= =?Windows-1252?Q?J4v8h9PsPPtUCtDZn2k91dE5qW4pbVg6nykpl1W4RQVhAwaHSBwIYbpH?= =?Windows-1252?Q?f+GYE092VzBcNdXQvkyKQT1GmwD2q/RLnbXSavc+33n5lK3XV1By68Ug?= =?Windows-1252?Q?vsV2CHSYFFDer4TWQGIoYg+Dk3FpopaZGWlaTC1jcdfU54Vd4GyCMuFo?= =?Windows-1252?Q?rxA2zh6FcKdyBU2GCwIwgeS+l4Fd6nb3jg/9f+BeCkQO4XitsATFEsfU?= =?Windows-1252?Q?wck13QKuX/VbChUkbcoJKn4Ii6xVipwXkqOG8Y0ZbMOT3oGQ0M1BXOpF?= =?Windows-1252?Q?8VznEFf20wDWS2DlFLHlNdBaQZHUgCHQfrhPGDIhMU+7ph0FkqA79aCH?= =?Windows-1252?Q?534NJiild0kN8jzIG47TGmQ98GOrf8csGahootN53b2LdJqja/DZ5trt?= =?Windows-1252?Q?sMYTZ1iK/h15jQkV2oErgSEYt/5l6HtErEyw10NjY/l0LY/ozaGPDYSO?= =?Windows-1252?Q?crw0IhSplB48dI7LyRSx2/XYyXcujticW3ySZXOCwZYzfWXqf/L2qIGm?= =?Windows-1252?Q?YtBmoRDY5botXUaSO6M0UBFp1uIOg1+Nte7UWFZSOx23WeskERqe63pp?= =?Windows-1252?Q?nK/PS8zs7s8HnSLWuUDNGSMflTuqN0FxCl3HH2ugtPQinKTK+EDEE0bF?= =?Windows-1252?Q?1RWH8AF2F90MzZfu9XuRVGa+SakkFg8bcJsFgQYZ+qRFyXmG84/GkpPZ?= =?Windows-1252?Q?jSvwjFkt9ZPMiCmCmCiMB1j2J3ua4ruW5OAIDQZPkvBvbeQePUI2C+EY?= =?Windows-1252?Q?H+XKYcJuIoT9VIZAzjuGWALEkFjZM4JeccGN+2x3BJX+Gbd/s5iCrjEa?= =?Windows-1252?Q?yGIYNJK1/UbKgpbfduytps6qL0iH99Wf5Q5Bs1S99jMlLAopYOa0/QIM?= =?Windows-1252?Q?aWXOGwDQ+fDllAWPkOmFW+pEt5/cA0WgzH4TmfX202OS1Mbl3U+XJVtt?= =?Windows-1252?Q?+D9AvU/tta0avaV9fLFNB6hwVWY8/BwVA0rae5LF8u+NgnchvH/Il8Zh?= =?Windows-1252?Q?Y/ltH0xnRWvRRBeY2h+M8wAB0aWVNHfMxR72Yjtt7Fej4TMITqTjlDUq?= =?Windows-1252?Q?1TxgC3SV9QQAJmM+Lqg9B2dWbFAkFV97AZlwXcKWsTWYVC1945dijZNm?= =?Windows-1252?Q?9CFYstmBu9m5nDFKiE3vAfdXEKxnFaeWbM5KnlPQtjc+hj8BmjXvASTB?= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 0763ea00-c3a8-45c5-586b-08d916eb03a9 X-MS-Exchange-CrossTenant-AuthSource: BYAPR10MB3240.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 May 2021 15:14:48.6669 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: rOuamdoYiQrONuFbDSEf43IoDdeFWFVmB07EG2eqhQRbhWWT8sdy2kGVwy3LziR84fUFj2UctPrPGah0X/LlnaIERIa8XqiHXOnyGvX1EgE= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR10MB4461 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9984 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 spamscore=0 phishscore=0 suspectscore=0 malwarescore=0 bulkscore=0 adultscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2105140122 X-Proofpoint-GUID: VzQI6JRt06HH9hdbop0SQ1hPhtJqkD_E X-Proofpoint-ORIG-GUID: VzQI6JRt06HH9hdbop0SQ1hPhtJqkD_E Received-SPF: pass client-ip=205.220.177.32; envelope-from=steven.sistare@oracle.com; helo=mx0b-00069f02.pphosted.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MSGID_FROM_MTA_HEADER=0.001, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Daniel P. Berrange" , "Michael S. Tsirkin" , Jason Zeng , =?UTF-8?Q?Alex_Benn=c3=a9e?= , Juan Quintela , qemu-devel@nongnu.org, "Dr. David Alan Gilbert" , Alex Williamson , =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= , Paolo Bonzini , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , Markus Armbruster Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/14/2021 7:28 AM, Stefan Hajnoczi wrote: > On Thu, May 13, 2021 at 04:21:02PM -0400, Steven Sistare wrote: >> On 5/12/2021 12:19 PM, Stefan Hajnoczi wrote: >>> On Fri, May 07, 2021 at 05:25:05AM -0700, Steve Sistare wrote: >>>> To use the restart mode, qemu must be started with the memfd-alloc machine >>>> option. The memfd's are saved to the environment and kept open across exec, >>>> after which they are found from the environment and re-mmap'd. Hence guest >>>> ram is preserved in place, albeit with new virtual addresses in the qemu >>>> process. The caller resumes the guest by calling cprload, which loads >>>> state from the file. If the VM was running at cprsave time, then VM >>>> execution resumes. cprsave supports any type of guest image and block >>>> device, but the caller must not modify guest block devices between cprsave >>>> and cprload. >>> >>> Does QEMU's existing -object memory-backend-file on tmpfs or hugetlbfs >>> achieve the same thing? >> >> Not quite. Various secondary anonymous memory objects are allocated via ram_block_add >> and must be preserved, such as these on x86_64. >> vga.vram >> pc.ram >> pc.bios >> pc.rom >> vga.rom >> rom@etc/acpi/tables >> rom@etc/table-loader >> rom@etc/acpi/rsdp >> >> Even the read-only areas must be preserved rather than recreated from files in the updated >> qemu, as their contents may have changed. > > Migration knows how to save/load these RAM blocks. Only pc.ram is > significant in size so I'm not sure it's worth special-casing the > others? Some of these are mapped for vfio dma as a consequence of the normal memory region callback to consumers code. We get conflict errors vs those existing vfio mappings if they are recreated and remapped in the new process. The memfd option is a simple and robust solution to that issue. - Steve