[{"id":3676622,"web_url":"http://patchwork.ozlabs.org/comment/3676622/","msgid":"","list_archive_url":null,"date":"2026-04-13T09:52:52","subject":"Re: [PATCH 03/14] vfio/migration: Cache stop size in VFIOMigration","submitter":{"id":84049,"url":"http://patchwork.ozlabs.org/api/people/84049/","name":"Avihai Horon","email":"avihaih@nvidia.com"},"content":"On 4/8/2026 7:55 PM, Peter Xu wrote:\n> External email: Use caution opening links or attachments\n>\n>\n> Add a field to cache stop size. Note that there's an initial value change\n> in vfio_save_setup for the stop size default, but it shouldn't matter if it\n> is followed with a math of MIN() against VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE.\n>\n> Document that all the three sizes we read from VFIO's uAPI on dirty or stop\n> sizes are estimates, so QEMU needs to always remember they can be anything.\n>\n> Signed-off-by: Peter Xu \n> ---\n> hw/vfio/vfio-migration-internal.h | 8 +++++\n> hw/vfio/migration.c | 50 ++++++++++++++++++-------------\n> 2 files changed, 38 insertions(+), 20 deletions(-)\n\nReviewed-by: Avihai Horon ","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=Nvidia.com header.i=@Nvidia.com header.a=rsa-sha256\n header.s=selector2 header.b=OuCdv9af;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists1p.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)","dkim=none (message not signed)\n header.d=none;dmarc=none action=none header.from=nvidia.com;"],"Received":["from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fvNCX3gnSz1y2d\n\tfor ; Mon, 13 Apr 2026 19:58:47 +1000 (AEST)","from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists1p.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from )\n\tid 1wCE3c-00033O-Ti; Mon, 13 Apr 2026 05:58:17 -0400","from eggs.gnu.org ([2001:470:142:3::10])\n by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from )\n id 1wCE3T-00032R-Pp\n for qemu-devel@nongnu.org; Mon, 13 Apr 2026 05:58:08 -0400","from mail-southcentralusazon11013016.outbound.protection.outlook.com\n ([40.93.196.16] helo=SA9PR02CU001.outbound.protection.outlook.com)\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from )\n id 1wCE3S-0002ut-Dc\n for qemu-devel@nongnu.org; Mon, 13 Apr 2026 05:58:07 -0400","from BL1PR12MB5063.namprd12.prod.outlook.com (2603:10b6:208:31a::11)\n by SA1PR12MB5670.namprd12.prod.outlook.com (2603:10b6:806:239::9)\n with Microsoft SMTP Server (version=TLS1_2,\n cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9818.20; Mon, 13 Apr\n 2026 09:53:00 +0000","from BL1PR12MB5063.namprd12.prod.outlook.com\n ([fe80::a0c2:5681:4aca:90da]) by BL1PR12MB5063.namprd12.prod.outlook.com\n ([fe80::a0c2:5681:4aca:90da%7]) with mapi id 15.20.9818.014; Mon, 13 Apr 2026\n 09:52:57 +0000"],"ARC-Seal":"i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none;\n b=PpiE2pKa/VKqGwzD/SrheuO7HGNV86qBFCxkjiO+7FJmaVygD5awl/BKvYRKg81pXjTmD0Q2JUiXdWtUQiD2SvBt1ZVPxjSVGbDe3nT1e4J0C4yAQf6iI/mW1fpRwfhxiFVUZgChOZDSGLeXrFiJe7mwPs1XevQZAI/HV8kU6rAC14omCwFKfXWYNbuw2A7tkq3SUC+Nov+xxqKd7ANACTwqnAQ5eMDjArRg7p3ZjKdH8Rx1s4up/cmMCDx9QppSAv6cjZaxv9IknDqRyLxSh4J43s1TWdTjOB8M43MCSAYMlTNKgSBIW4tj4qtAkJrCrzYe6ReoPLqClgKWBVzpDw==","ARC-Message-Signature":"i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com;\n s=arcselector10001;\n 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;\n bh=chJhiUdAn1gfqdYPHJcavYcd3xdJDzeu2JdHAFUPtSE=;\n b=E08PBAGblOaXzsuOxNoetRBOeX2m1fm0NUBWW+CjT8+rC5a9YOxOUATc6SiBuSSU0OsAepbnCeJNl52uru/IdIxjMkfKfihjMLe+tcItxWajIO6uHXf57vQpYuFmV871mqxtHmTAXwJiPd458bwHKubJHm2TTDDQEU1uqjz3Ej6RweX3DLXn93kzLjw5G0v/5/LGmWV/GeL63aRvIEuTu/3RBc9mKpAGsBK5PVfY4l117Bgo+Yv/I3ev56C3Dh4kIDAAx+ralJORLJQzJ/2m4f+Q1N7fXM7rwRsyBR77MrKfmYd1vayOnqXuI+55d+0HeZgNV9EgLxMSDsuH+7J4Dg==","ARC-Authentication-Results":"i=1; mx.microsoft.com 1; spf=pass\n smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com;\n dkim=pass header.d=nvidia.com; arc=none","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com;\n s=selector2;\n h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck;\n bh=chJhiUdAn1gfqdYPHJcavYcd3xdJDzeu2JdHAFUPtSE=;\n b=OuCdv9af5KwF+C0W941J3DIyp9nYsddBIymkXMYdWPtxHpxHUq8DBNZvcpQMWg+luimjqqdv49jHMd+6DVhnmTOB7uc/8z/YS8OHtNaO/n+/iOxEGj7GGriq88HTpob91DtxgTXmARyFOsz7LMaOY2kajxc1kd1q3DegMRhO90JCVWU8Uk/gueQYo7TIedPC9FAgX67dJFNW3MlB4IO46M52nwkdHAvc/iZwirmnXIrr/gconaN6CUoIO1N6Udja6sT8Laa/7ah/52OUdqL+CUvwN1ZPVtYf2yqin6pdgSVCFk57Zf3KgAMAfYSNgyn41IZ12j1bwCZQCi4PGo0MMQ==","Message-ID":"","Date":"Mon, 13 Apr 2026 12:52:52 +0300","User-Agent":"Mozilla Thunderbird","Subject":"Re: [PATCH 03/14] vfio/migration: Cache stop size in VFIOMigration","To":"Peter Xu , qemu-devel@nongnu.org","Cc":"\"Maciej S . Szmigiero\" , =?utf-8?q?Daniel_P_?=\n\t=?utf-8?q?=2E_Berrang=C3=A9?= ,\n Zhiyi Guo , Juraj Marcin ,\n Prasad Pandit , Kirti Wankhede ,\n\t=?utf-8?q?C=C3=A9dric_Le_Goater?= ,\n Fabiano Rosas , Joao Martins ,\n Markus Armbruster , Alex Williamson ","References":"<20260408165559.157108-1-peterx@redhat.com>\n <20260408165559.157108-4-peterx@redhat.com>","Content-Language":"en-US","From":"Avihai Horon ","In-Reply-To":"<20260408165559.157108-4-peterx@redhat.com>","Content-Type":"text/plain; charset=UTF-8; format=flowed","Content-Transfer-Encoding":"7bit","X-ClientProxiedBy":"TL2P290CA0021.ISRP290.PROD.OUTLOOK.COM\n (2603:1096:950:3::15) To BL1PR12MB5063.namprd12.prod.outlook.com\n (2603:10b6:208:31a::11)","MIME-Version":"1.0","X-MS-PublicTrafficType":"Email","X-MS-TrafficTypeDiagnostic":"BL1PR12MB5063:EE_|SA1PR12MB5670:EE_","X-MS-Office365-Filtering-Correlation-Id":"de68f0a0-6676-4d5d-1cea-08de994270c9","X-MS-Exchange-SenderADCheck":"1","X-MS-Exchange-AntiSpam-Relay":"0","X-Microsoft-Antispam":"BCL:0;\n ARA:13230040|376014|7416014|1800799024|366016|56012099003|18002099003|22082099003;","X-Microsoft-Antispam-Message-Info":"\n jV0FL8N663c6YnSv2QdObGtF0qp2/aDyv5Hi9guQ57LWcsUmzfODeC/u1Xz8zqpX1nOJ8MH2Uq7E9tZlUTXoPxp8xrFCZnxa04qbF1jX3c6/3RJpTJFWXvGTFihF9KmqP0/yOxN+JfUKAXLW9hqei6l8ohVgjYlvy9Qum3sNZeyD4C4eNMNkO8Jy4d1UCeWzM1lRU9gsbPTnYKYJ+dQTZQ1FkCQPlhSJVNEp53mvv12x+37lyJhN2ZzbE+0VXTf93yL16NdW64qxOgrExDT+xvSJG0hMPpBweoNtSQS876vAhZokcNqoiRLhS8KTLsTdq6WhRQqY2UGmPazwVhphrc4nYgtSEwXTNKi0JpIlpyFE/AdjnT3jAw9fxaUTsqHzuTN3cKOgGooRbePUUwHGw0ytt6THjVgkK+UIrdY+bRippl3oQl/VToB6FRxfJyDGnKuxkuPk2eIq4LmpdYmk4Ga6jKDEKA6zJ9mnzuE+ooWr2iRwmCaQ2tXbsQu1xQ2s1mucge+QR/bfTXgllm7BOqnTMBMeUYgKzEBJskDvNRE58LyPUFsgiEbww5ljhhNKpG1la/sifor2y7rIjnxkazUf7T/uOuZBLUR0rDryOtvID5uOM9rhb+kq64ydvumBa92YE2GeqdF/WAU6erdE+8ud9AeaL0bqCssGK9t7XhjTIXq8aZu5hzVGAjW+4+UAy3HXBQI+kNmm3FOwlIEzZisqV79rorakXeCXf746ZSA=","X-Forefront-Antispam-Report":"CIP:255.255.255.255; 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