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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1B63DC4332F for ; Fri, 18 Nov 2022 12:52:35 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.445720.701038 (Exim 4.92) (envelope-from ) id 1ow0qr-0000wR-71; Fri, 18 Nov 2022 12:52:13 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 445720.701038; Fri, 18 Nov 2022 12:52:13 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1ow0qr-0000wK-3h; Fri, 18 Nov 2022 12:52:13 +0000 Received: by outflank-mailman (input) for mailman id 445720; Fri, 18 Nov 2022 12:52:11 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1ow0qp-0000w9-82 for xen-devel@lists.xenproject.org; Fri, 18 Nov 2022 12:52:11 +0000 Received: from esa5.hc3370-68.iphmx.com (esa5.hc3370-68.iphmx.com [216.71.155.168]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id ceb74989-673f-11ed-8fd2-01056ac49cbb; Fri, 18 Nov 2022 13:52:08 +0100 (CET) Received: from mail-mw2nam04lp2169.outbound.protection.outlook.com (HELO NAM04-MW2-obe.outbound.protection.outlook.com) ([104.47.73.169]) by ob1.hc3370-68.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 18 Nov 2022 07:52:05 -0500 Received: from SJ0PR03MB6360.namprd03.prod.outlook.com (2603:10b6:a03:395::11) by SJ0PR03MB6568.namprd03.prod.outlook.com (2603:10b6:a03:389::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5791.25; Fri, 18 Nov 2022 12:52:03 +0000 Received: from SJ0PR03MB6360.namprd03.prod.outlook.com ([fe80::2393:22c1:7766:5caa]) by SJ0PR03MB6360.namprd03.prod.outlook.com ([fe80::2393:22c1:7766:5caa%5]) with mapi id 15.20.5813.016; Fri, 18 Nov 2022 12:52:02 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: ceb74989-673f-11ed-8fd2-01056ac49cbb DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1668775927; h=date:from:to:cc:subject:message-id:references: content-transfer-encoding:in-reply-to:mime-version; bh=Agxby2pijlhMwYVGLa8pxS5eMWT5TtI/GCBc+Zr0uoU=; b=NDHCibeu9nDbA8Cq7UFI7YrPBa+4fbKFBJsc4WtOD5LMAf6+Pb0j+/nw XfvtPc/biJtt8/8BaH1DVnAi0fwm5p0r9t4AwBITR8WpAM8wx5bu6aEY/ Q08qW1SXXZOV94YmE9MZVoN2tgQRfnxRLWUlwP6FTbukJ0dG+Pk6gPiH8 g=; X-IronPort-RemoteIP: 104.47.73.169 X-IronPort-MID: 84169992 X-IronPort-Reputation: None X-IronPort-Listener: OutboundMail X-IronPort-SenderGroup: RELAY_O365 X-IronPort-MailFlowPolicy: $RELAYED IronPort-Data: A9a23:DLyTkaO8AtH/WtXvrR2QlsFynXyQoLVcMsEvi/4bfWQNrUp2gmQPz GEcD2iEbPaPMzTzL992b9m2pkoPsZDVzddlHQto+SlhQUwRpJueD7x1DKtS0wC6dZSfER09v 63yTvGacajYm1eF/k/F3oDJ9CU6jufQA+KmU4YoAwgpLSd8UiAtlBl/rOAwh49skLCRDhiE/ Nj/uKUzAnf8s9JPGj9SuvzrRC9H5qyo4mpB5wxmP5ingXeF/5UrJMNHTU2OByOQrrl8RoaSW +vFxbelyWLVlz9F5gSNy+uTnuUiG9Y+DCDW4pZkc/HKbitq/0Te5p0TJvsEAXq7vh3S9zxHJ HehgrTrIeshFvWkdO3wyHC0GQkmVUFN0OevzXRSLaV/ZqAJGpfh66wGMa04AWEX0tZdP21Ux NEmE2gERD+Djf+Yh5Wma+Y506zPLOGzVG8ekldJ6GmFSNMZG9XESaiM4sJE1jAtgMwIBezZe 8cSdTtoalLHfgFLPVAUTpk5mY9EhFGmK2Ee9A3T+vFxujaCpOBy+OGF3N79YNuFSN8Thk+Fj mnH4374ElcRM9n3JT+toi712L6ezHmTtIQ6DL6h2dFyx2Wv7DZMDh0ScHiCpNX+hRvrMz5YA wlOksY0loAw/kG2Stj2XzWjvWWJ+BUbXrJ4A+A8rQ2A1KfQywKYHXQfCC5MbsQ8s807TiBs0 UWG9/v2ARR/vbvTTmiSnp+MpC62ETgYKykFfyBscOcey9zqoYV2iw2VSN9mSPKxloesR2C2x C2Wpi8jgblVldQMy6iw4VHAhXSru4TNSQk2oA7QWwpJ8z9EWWJsXKTwgXCz0BqKBN/xooWp1 JTcp/Wj0Q== IronPort-HdrOrdr: A9a23:6fg7XKlbx3tJpjDd7Yh13ioAF7npDfNMiWdD5ihNYBxZY6Wkfp +V8cjzhCWftN9OYhodcLC7V5Voj0mskKKdxbNhRYtKOzOWw1dATbsSlLcKpgeNJ8SQzI5gPM tbAstD4ZjLfCJHZKXBkXaF+rQbsb66GcmT7I+xrkuFDzsaDZ2Ihz0JdjpzeXcGIDWua6BJdq Z1saF81kedkDksH7KGL0hAe9KGi8zAlZrgbxJDLxk76DOWhTftxK/mHwOe1hI+VSoK5bs562 DKnyHw+63m6piAu1Xh/l6Wy64TtMrqy9NFCsDJos8JKg/0ggLtSJV9V6aEtDUVpvjqzFoxit HDrzopIsw2wXLMeWOepwfrxmDboX0Twk6n7WXdrWrooMT/Sj5/I81dhbhBeh+cz0Y7ptlz3I 9Cwmrc7vNsfFv9tRW4w+KNewBhl0Kyr3ZnuekPj0ZHWY9bTLNKt4QQ8G5cDZ9FNiPn74IMFv VoEajnlb9rWGLfS0qcknhkwdSqUHh2NhCaQnIassjQ6DRSlGAR9Tps+OUv2lM7sL4tQZhN4O rJdo5ykqtVc8MQZaVhQM8cXMqeEAX2MFzxGVPXBW6iOLAMOnrLpZKyyq4y/vuWdJsBy4Z3sI jdUWlfqXU5dyvVeIKzNaVwg1DwqViGLHfQIpk03ek6hlS8fsumDcS7ciFuryP6yM9vR/EyWJ 6ISeBr6rHYXC/T8L1yrn3DsqlpWAcjufIuy6cGsnK107b2w97Rx5vmWceWAobROhAZfU66Kk c/fVHIVbZ9BwaQKzLFvCQ= X-IronPort-AV: E=Sophos;i="5.96,174,1665460800"; d="scan'208";a="84169992" ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Ix/BDmO+mWR6tWqBelzifYh1yEB5Npb7j0x1zlM+RH71VJ/Cj8DYD8yg85jnxQmV/Bx8btcyVezPA4bEIOtlaFs3AlExTnafARexBqKx0Ykha2VVbqDXTBdTMi8voFcAYRDWkFexbwhTIIrJp1a6/Z0aF80wulHlQ5a6SHFlTe4sQb+FjqA7HL8SE5WRuPlDblbLZ4hAJuvpTQglYyTv79jCvRF4NZJUKdruEle8hfaPEZhYMDpYBZBpfy/HnJ6DRkKXVnouhQe/cyr8FFWDzHkTtakrQvHpUYIhvL/4xEodpW8fOSAZyU3PgFleRosuIod0hh/TWcVjtS2aHeCd/A== 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=b8RNHA89uM0j2X61JYjokoiSPQ3LqYMtOeXQ5jYT2Xk=; b=lXMcCAZkp1mf9evurSi+ckfbHZJE5iyK2bFR6eKKkHhz0+dJr3Ne6zN/BiCXyd/9bptdAntShlEekJlT4Xiaoa0CoVYItdzTrLkYUG5AHBKnsyIOckWhswK5bTk+GChuII3Dki2J+Ga53hvJ+82BQI354i33p9TlyR4IPBK4g9b+bSgzNC0MjWCqJDkvsbc3jCEwCmhKf7gq8hsuC6j8bekJXR7/qQ15cy1MWQq2evSHr2u++256RaI69nbh5and3lGK0CaSqYKHXoz3wNZ0XOwzObIkd6LQasx59ZkYRsSgRNskXmswy+XOwC28SyR1c8fmW4SIlHejY2zFJkP7Ow== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.onmicrosoft.com; s=selector2-citrix-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=b8RNHA89uM0j2X61JYjokoiSPQ3LqYMtOeXQ5jYT2Xk=; b=FS/e4YjOAiELcbwda82hOYSS1kiDo9BimpfvGTuz0Gsj2yC2z5HPYOvAyn7ASgol9P7naSRFSVcmlpn04vgExWOn0rwa2/kqpwps3MI+awlzhIVhD9bnn8jGvIvh1Zyg1pshL7OAtJePLxUVnRM5eDRfbsWrnWl4Jf2fbzzWikw= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=citrix.com; Date: Fri, 18 Nov 2022 13:51:56 +0100 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Andrew Cooper Cc: Jan Beulich , "xen-devel@lists.xenproject.org" , Wei Liu , Paul Durrant Subject: Re: [PATCH] x86/HVM: don't mark evtchn upcall vector as pending when vLAPIC is disabled Message-ID: References: Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-ClientProxiedBy: LO4P123CA0576.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:276::23) To SJ0PR03MB6360.namprd03.prod.outlook.com (2603:10b6:a03:395::11) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ0PR03MB6360:EE_|SJ0PR03MB6568:EE_ X-MS-Office365-Filtering-Correlation-Id: 07b8caec-df8a-49ee-e110-08dac963afe9 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:SJ0PR03MB6360.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(7916004)(4636009)(376002)(396003)(366004)(346002)(136003)(39860400002)(451199015)(6666004)(54906003)(6506007)(5660300002)(8936002)(186003)(8676002)(85182001)(6636002)(6862004)(82960400001)(9686003)(53546011)(66476007)(83380400001)(38100700002)(66556008)(86362001)(66946007)(41300700001)(4326008)(6486002)(26005)(33716001)(2906002)(478600001)(6512007)(316002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?d2RFVElndXJZSXYrTzBheWlaeW4zMkhkQnpBdnFrU1VuL0lNczlCVHc3STFz?= =?utf-8?B?aDg4OCtNMnFhZFVJWHNpOHlGR3FnMklMVTdKVEw1cUlSOUxKOVZHZ0hocXMr?= =?utf-8?B?Qzhid1VlTmVObnY1NllzRTBzeUExeU5QVytkZEs3N0c5REZkTzR3cEloTytK?= =?utf-8?B?Q1dvV2lHbjlqQy9PMXIwZEdRbElMd2k0SXhwQUlLTzlvU0hOb3hZYUNFdWtL?= =?utf-8?B?RDVuMzU4ZHJCQkhTUHZxTjZIb3BtMWtMbnRyVWJUUVVaNmc1TzcvejQyeHpP?= =?utf-8?B?Z2pGTVQyUktWczJ5OXI1am9CZEVuVUpjVU9IQU5yeWV5czd5SHU5YkNUM3BJ?= =?utf-8?B?c3lKK2tDQ1hFVXJmcGxkRDZzSElka0hOaCsvaWlKcFhlbXdoQlVReGhFTFNO?= =?utf-8?B?ZDhIc1VXRGMwdUYwWTl6VUloQ05OUnBHN0tJVEx3eG85bFJWQXRwejdHalhJ?= =?utf-8?B?bFBraExTQmp3dzBDcU9MTTd2WDlXVEo4OWNjZXpXN3VXTk52NlpTeFlwOWJU?= =?utf-8?B?TTZNbWR1YlV1bWtLbHFTYVJEcCtWQmxWK09DUEFvbWxEbmVkbFhvbEtCdmwz?= =?utf-8?B?eW5FaDdVdVlkWEUzaFhDNDRVbWRCTlkwUjVQU0ZLckJYRG1sbXVCZFRHK0x3?= =?utf-8?B?My8zbHUvME5oZXEwVEZpZnJQME1KZVZIdFZ3eXErMG42WERkSGF3UlpGVkFV?= =?utf-8?B?V2NhbEFCOVI1TnJDU0dSOXRTdW1BMXpiN1diNTBZRGdiMlV4M20xMWFLZmJY?= =?utf-8?B?bmtPTnYrOVZIWjdvZzFUQUFMTkdZQzY1aC93RlFEcXJkMmMxU0hEeUdpVnZD?= =?utf-8?B?WjJWaVNYUExNbnBlWEc0QkxBMVFQSEprall6dGVMQlpzV1laWDA5S1RoL2xS?= =?utf-8?B?NHlqd094M1ViVlRCOXFGVmlWeG5NRXN1OVg2L3duYnFRaFhWKy9mTXVGeTJO?= =?utf-8?B?U2dNNERiQXh4S1k2R1E1VGgwbXdMcGN5Zm9iYXVYNEZaWjIxcVR6MC9sTHY3?= =?utf-8?B?RWNxdy9xS3BjclBvd2QwcGRVbnM5VWxpYnNNcTU1UU9UUWNSSnJQcHc5TERG?= =?utf-8?B?MlE3N3NZQ00wWjRLbnlGam9KSDNYd2o3S2NLbFRPeEdCdGM0bTFpTVozWnlH?= =?utf-8?B?d0kwYVJubEZvdFJUZFZLSEEwamJmeW4yR25Tcnl0YjNOZnZxdGw3MmFUeGph?= =?utf-8?B?cWJjQ2JTck5qbVAxT3ZQQTJPZ3JBMWpCUCtBRmZ6dFVzM3RQZ2U4MTRwUm42?= =?utf-8?B?SWVaQ0M4ZHV5dGIzaUx6eTR0Q3RVbncxeHVvOUJxZy9sdStmcmM3RTZtUGE0?= =?utf-8?B?bXZ1UUZQSFlSZ3VLZGRnSXpzYS9yVVlqbTlUcWJ0WEgyVjB3SjIzM2JjaFdW?= =?utf-8?B?czFWTnJuMUJJOXNEU3N3YWE5cDR1S2xJNWxRM0RSczhOMGhRTWloS2xlbXM4?= =?utf-8?B?eXp0VHhpYUIrNG54SGREc1JiVGd4OFFEbjJheUFOZ2xHb1FGOG9DUWEvUUgv?= =?utf-8?B?blFlRy9qTFNLY2FXKzJ2ZkRQdTBQWTJMQkVHdFpxajBncWl3WTVVQUZSa0wy?= =?utf-8?B?Mk1CU21zdU9lVzAzZjB3L3I4VlFDSVQrQnBqeWwzbDZNaWlkVE9BSDRYN0Uw?= =?utf-8?B?dXdaSkEvM3UyZmpWN1ZWQlNaQlZkZjdQTTdkWVJLdEtLS3dYbVo4U1pqTGl1?= =?utf-8?B?bVplNEJjTVV6a0E5VXlsTlVjVDY0a1prNm1BMHRaeXovNExYSXFKeFlTTmp3?= =?utf-8?B?cHI1VDYwS3JtV3k0dFVhdm10dWgxMWpINmNacHc4QjdqWVdoSTFuc3p4RklF?= =?utf-8?B?TCtCUVVhYlBINUVNOTZyTk5YR05oWndObjBZTkJ1TTQvOGxtM0ppVG55TlNz?= =?utf-8?B?WVZRTDdrdldQZkwrV1ptL3RYNUZlQTdMVTJlbm0yVGVNbjdRcUpWQmJqdGdQ?= =?utf-8?B?NXRxYnN2Q3FoelRQSWFjM1RXbks0K3RQeXhOU21TdWRvb1F0T2JBcnMvb1VO?= =?utf-8?B?Sk1sVmU1bTdSUkRrRTZMVUhzUzcveTQ5cTUzWHJvU3JPWkhvdmlHQUkwMmxx?= =?utf-8?B?cGp5YXNjZ01zZ0FZeDVVQkRyQkZVSU5XMkdYTnQ0Q2UyMnBJUDVaZkVLS0dp?= =?utf-8?Q?Lf8zQPFQnEHnKUOnn7CKGFkW0?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: citrix.com X-MS-Exchange-CrossTenant-Network-Message-Id: 07b8caec-df8a-49ee-e110-08dac963afe9 X-MS-Exchange-CrossTenant-AuthSource: SJ0PR03MB6360.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Nov 2022 12:52:01.9627 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: gEwC30MJ4hXeuGqNRxlc8OY8utmQsEiEq+iFiM8oOM3SUPUKT6Nq9WptOqkRQOm9uzZXReBGkZXDOYgWZRzlJQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR03MB6568 On Fri, Nov 18, 2022 at 12:33:00PM +0000, Andrew Cooper wrote: > On 18/11/2022 10:31, Jan Beulich wrote: > > Linux'es relatively new use of HVMOP_set_evtchn_upcall_vector has > > exposed a problem with the marking of the respective vector as > > pending: For quite some time Linux has been checking whether any stale > > ISR or IRR bits would still be set while preparing the LAPIC for use. > > This check is now triggering on the upcall vector, as the registration, > > at least for APs, happens before the LAPIC is actually enabled. > > > > In software-disabled state an LAPIC would not accept any interrupt > > requests and hence no IRR bit would newly become set while in this > > state. As a result it is also wrong for us to mark the upcall vector as > > having a pending request when the vLAPIC is in this state. > > I agree with this. > > > To compensate for the "enabled" check added to the assertion logic, add > > logic to (conditionally) mark the upcall vector as having a request > > pending at the time the LAPIC is being software-enabled by the guest. > > But this, I don't think is appropriate. > > The point of raising on enable is allegedly to work around setup race > conditions.  I'm unconvinced by this reasoning, but it is what it is, > and the stated behaviour is to raise there and then. > > If a guest enables evtchn while the LAPIC is disabled, then the > interrupt is lost.  Like every other interrupt in an x86 system. > > I don't think there is any credible way a guest kernel author can expect > the weird evtchn edgecase to wait for an arbitrary point in the future, > and it's a corner case that I think is worth not keeping. We would then need some kind of fix in order to clear evtchn_upcall_pending, because having that set without an interrupt pending on the vLAPIC will result in no further event channel callback interrupts being injected (see vcpu_mark_events_pending()). Maybe we want to change vcpu_mark_events_pending() so that it always tries to inject the vector even if evtchn_upcall_pending is already set by calling hvm_assert_evtchn_irq() unconditionally? Thanks, Roger.