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=-7.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 04F42C43460 for ; Mon, 3 May 2021 19:18:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD2CE6135F for ; Mon, 3 May 2021 19:18:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229620AbhECTTG (ORCPT ); Mon, 3 May 2021 15:19:06 -0400 Received: from mail-eopbgr50107.outbound.protection.outlook.com ([40.107.5.107]:30183 "EHLO EUR03-VE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229590AbhECTTF (ORCPT ); Mon, 3 May 2021 15:19:05 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=XZaZBRA5Z2Dz9XYp+9SIJZld7LE1dRMI5v10D20rXxdOtEJF0zjWZfudpZtwamaGO7RJadCry6f5wmca7o8zR0WJhKqyrfZZgLRntIpoAECVjDeUPteXdMiaSi798JEe5ssEytRETHr6XXS1aFcFY5vU1WcZJc5myQvykFQP7HdKvt5aTVgIpbgvSGd6mHeDrHX7b5e0+MhB8SgRv67tfm2Okx+OD3HOtzLy510xXXpZDUV7kVV/bn6hxC5nqGus7txsM6/oqofUqESEbepf0yJf37muEV5octAuf5LFSD7q/eDBdiiDpIh+h3xTeN/xJLIi2DyIbVgmZIHZH6ZE2A== 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=q6Ijbow1BmI+nzq00NCW+Zi6HNFQeeR8N7jHlzCs1SA=; b=NzzP5ixouf09OsNwxI9bIE6MMehARzmAWfDe7k156RZJA4KYg2OpejrrVnhu0U289wUCkQ4CHfFpeoMrCR+cwS9FX+55ReZd+35lvyOV5D6VhRja+whR4Lwv5yuR1Krvied1eyBd5jqy1sPVNl2ghxUI7fvYhcSTtWdNCEvPAB8YxrwB0sERKOqyPF1/GPg7z6/dJWR3kVg9u0YR3iETXgrW2QKCoEKNtfEEsYYXk5asJ035KFfa8NdL4KjDqJ1FDbNkDMCrYb5s7rH0zZU6wLEHMfpwz5A2y5atKNiInFQS7Ult0qQJJALZXOSQuKHi8zwnQEguS8W6L4LGpg2wCA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=virtuozzo.com; dmarc=pass action=none header.from=openvz.org; dkim=pass header.d=openvz.org; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=openvz.org; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=q6Ijbow1BmI+nzq00NCW+Zi6HNFQeeR8N7jHlzCs1SA=; b=nFH888H4nov6vQBfoFOba/shD/xXfpnSmvqbqAOO8ckMdGaqRc1eY5E1xLFupS4hQd5VI+02Aw9TwMGkQuoR/ZoCJTv/OVzAiYhFplPArGQnUalLn/iHubrrgdXsmFe/i+iokNZNAHSjbn/zk6S9lEwkb+nkgzH/1vIQ9BUhYF8= Authentication-Results: vger.kernel.org; dkim=none (message not signed) header.d=none;vger.kernel.org; dmarc=none action=none header.from=openvz.org; Received: from AM6PR08MB4214.eurprd08.prod.outlook.com (2603:10a6:20b:8d::30) by AM6PR08MB5077.eurprd08.prod.outlook.com (2603:10a6:20b:e6::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4087.38; Mon, 3 May 2021 19:18:09 +0000 Received: from AM6PR08MB4214.eurprd08.prod.outlook.com ([fe80::fc46:c7a8:e09:8dfb]) by AM6PR08MB4214.eurprd08.prod.outlook.com ([fe80::fc46:c7a8:e09:8dfb%2]) with mapi id 15.20.4087.043; Mon, 3 May 2021 19:18:09 +0000 Subject: Re: [PATCH v4] KVM: x86: Fix KVM_GET_CPUID2 ioctl to return cpuid entries count To: Paolo Bonzini , Sean Christopherson , Valeriy Vdovin Cc: linux-kernel@vger.kernel.org, Jonathan Corbet , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Shuah Khan , Aaron Lewis , Alexander Graf , Andrew Jones , Oliver Upton , Like Xu , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20210428172729.3551-1-valeriy.vdovin@virtuozzo.com> <0d68dbc3-8462-7763-fbad-f3b895fcf6e6@redhat.com> From: "Denis V. Lunev" Message-ID: Date: Mon, 3 May 2021 22:18:06 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 In-Reply-To: <0d68dbc3-8462-7763-fbad-f3b895fcf6e6@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [31.148.204.195] X-ClientProxiedBy: AM0PR10CA0008.EURPRD10.PROD.OUTLOOK.COM (2603:10a6:208:17c::18) To AM6PR08MB4214.eurprd08.prod.outlook.com (2603:10a6:20b:8d::30) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.1.36] (31.148.204.195) by AM0PR10CA0008.EURPRD10.PROD.OUTLOOK.COM (2603:10a6:208:17c::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4087.27 via Frontend Transport; Mon, 3 May 2021 19:18:07 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: e136411c-b35b-4f46-f722-08d90e682fb5 X-MS-TrafficTypeDiagnostic: AM6PR08MB5077: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:6430; 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:AM6PR08MB4214.eurprd08.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(39840400004)(346002)(136003)(396003)(366004)(376002)(7416002)(66556008)(2906002)(31696002)(26005)(66476007)(66946007)(186003)(36756003)(6486002)(53546011)(8936002)(316002)(4744005)(16576012)(5660300002)(83170400001)(110136005)(54906003)(8676002)(31686004)(52116002)(956004)(38350700002)(4326008)(16526019)(2616005)(38100700002)(478600001)(42882007)(43740500002)(45980500001);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?Mk92b01ZYWY4SzhiWDE1d2pxNzlwOEkyMnNva202ZHBtTk0renRxb3djV0FD?= =?utf-8?B?dTYxekNxenlDTWE5S0xVV1VrOTVNZVZNczB1QXd1VW1yMXN0eVRXdGlNcVhm?= =?utf-8?B?c1I0cUJvK1VGRkJJdVlhWVZlVEZXeG41Ti9YMUtMZ2ExSVMvQkdEMFpHVjFN?= =?utf-8?B?M3lnR0l6M2hHWWtCc0tNRjhtNUNobU4vbnFWTTA2RWRXS0lYM2dIaHZQM3Mr?= =?utf-8?B?WHlsLzNMbmY1YnQyMHJtdGkyY1ptRVQrb1JtbzcxbncrN1Q5UnpWQkpObGRG?= =?utf-8?B?clMxbzByNVN5a3pLZ05jNzdJTENkL0RTaVpVZm41ck1nT1NHOTl4dDZQOGtz?= =?utf-8?B?UEdyNXIwYVVHUlpSQlZBSEk0aGY0UC9oN0llYjNVTzlERjM2dDk5YzJ0NWdT?= =?utf-8?B?WDk5TG1Vd3ArTEJiQjRvMkJiVS9JMTV5c00xZFNXWU9YK0pOSXdVcG03Z0Zt?= =?utf-8?B?VHpGR3l0YzRIMy94MFp6REJpeDZ6U0w4QU9WSjBGaFhXdDVYRTA3RGN5U3U2?= =?utf-8?B?NjJhZ3JWRlhDZHhyNnljUFExTUZNeEdlemhwR1BPS2tZMTBia2tBeEV6VkR6?= =?utf-8?B?ZS9yVUQ1T2FUb1JYdG9iSFF6UHJMSUZkaU5hT2JFNzBrWWhjM0o2N01DQ2VV?= =?utf-8?B?RDREdWhpMmdoQ21LZFFrTk1HRzRsbVZ4OC9ac0daS1hLalRHdTk0ekNnRk1S?= =?utf-8?B?QmRhK3JUNlVpMFdFT1RXN2RVN3lEd0tBTTdUdEtUT1E2TWpwS3ZkU2tPS1dD?= =?utf-8?B?SWZaeVFsRmh1ckw5Q2kzTld5aDl5QXNVL0lSb3FpRmpFZVlsdGVwOFAzQXVv?= =?utf-8?B?UkZCU2dpdFBIdTNOd3kyRWRPbTFQNTZRVjZ0Q29ISG1RZGVVSllIbDV4ZUEx?= =?utf-8?B?WUEra01tWXhYMzJSRVBoQSs4MDhQZVdFUFlad0t5L2xIZW5SRHg1dTFyVjNJ?= =?utf-8?B?L1BQQXp2RE1peDZhN3M2NHdyQXIxT1l3bHdPanEvVm9zZjcwQjFGZ0ptbHZs?= =?utf-8?B?Z1pZU2hLYzIxV2FseDBwZWtpTzErQ1ZyOEVVQWFQbERkTzdUZTRtZXo5U2Qv?= =?utf-8?B?Qzg0ZHpiSlBNcDZRWmdRWnhhcFFMeTZBYXVKbnNzOFZqMHl5WFhDQVl2b2s5?= =?utf-8?B?NU9La0gwTXNwaFhEQ09vWDlKbGRqdXdORU1uL29NZTJSeXFrUEY3QTlzcjd1?= =?utf-8?B?ckpzOENaejNGUkFydVR2S3lMYmRTbjJsdnhobHZGcGNWaGcyaXhaQjZDZGEr?= =?utf-8?B?ZjNKbVR3TkNyNU9DSFhjbzMrM0xFMS9Va1VWQWdmQVpoZDdVbVZWWUtYZzdk?= =?utf-8?B?SWNPZVFoVFhzWFV0TmlSMjJTTkN0aE1JSG1XTWViUVprVkpPNGZDTFhiL3pi?= =?utf-8?B?YkJueHBibExncWtIdTRwSW5XM3dpd24vRmdTUHBHcTZtekZuL25CU1dtR3dG?= =?utf-8?B?WWV1TDZRaVR5bFNmVnB1OHg4ZFpNTWZVMHQyTHEreW9xTDRMS2V2WUtpdlFQ?= =?utf-8?B?aUJ6VmNFUXpEa01Zb0htY0lXbThOaVBaK2s1Y0NKcC93WC9OVVZVWlhWSitl?= =?utf-8?B?THRMT3JUS2w4RmNUeTBPcGJMRTdSbVBNUmNoRXFUN2Q4NHlwNDhkRnpVMG9t?= =?utf-8?B?bE9UcnVNUzFRc20vc2psRTVwSnJ4OE9nWndQRFRHMGV6OXVSSGZSSUFLWEZB?= =?utf-8?B?VzB3M1R2SGNjM0owQmtyMnVTbzYzTkxUTEFqZlBJSGQwVisya2I1MUljRXdi?= =?utf-8?Q?CdKk1lHE9Zm+xq493uBx8mYzttDwKvjnp/NutfF?= X-OriginatorOrg: openvz.org X-MS-Exchange-CrossTenant-Network-Message-Id: e136411c-b35b-4f46-f722-08d90e682fb5 X-MS-Exchange-CrossTenant-AuthSource: AM6PR08MB4214.eurprd08.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 May 2021 19:18:09.2686 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 0bc7f26d-0264-416e-a6fc-8352af79c58f X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 35OqNoQ3okcC0zx0ww57rW+HozyEMWhqgdl83XiAFdOALvx8+HH+Mi1hftL8jQQpAic6Ke19C/Jtk7I8X6Hapw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM6PR08MB5077 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 5/3/21 5:54 PM, Paolo Bonzini wrote: > On 29/04/21 03:00, Sean Christopherson wrote: >> On Wed, Apr 28, 2021, Valeriy Vdovin wrote: >>> It's very explicit by the code that it was designed to receive some >>> small number of entries to return E2BIG along with the corrected >>> number. >> >> LOL, saying KVM_GET_CPUID2 was "designed" is definitely giving the KVM >> forefathers the benefit of the doubt. > > I was going to make a different joke, i.e. that KVM_GET_CPUID2 was > indeed designed the way Valeriy described, but that design was > forgotten soon after. > > Really, this ioctl has been such a trainwreck that I think the only > good solution here is to drop it. > > Paolo > should we discuss KVM_GET_CPUID3 which will work "normally"? Den