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 7B446C433EF for ; Mon, 13 Jun 2022 08:22:18 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.347834.574155 (Exim 4.92) (envelope-from ) id 1o0fKP-0002OW-RL; Mon, 13 Jun 2022 08:21:41 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 347834.574155; Mon, 13 Jun 2022 08:21:41 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1o0fKP-0002O6-LB; Mon, 13 Jun 2022 08:21:41 +0000 Received: by outflank-mailman (input) for mailman id 347834; Mon, 13 Jun 2022 08:21:39 +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 1o0fKN-0002O0-Kj for xen-devel@lists.xenproject.org; Mon, 13 Jun 2022 08:21:39 +0000 Received: from esa6.hc3370-68.iphmx.com (esa6.hc3370-68.iphmx.com [216.71.155.175]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id d7a28907-eaf1-11ec-8901-93a377f238d6; Mon, 13 Jun 2022 10:21:38 +0200 (CEST) Received: from mail-dm6nam11lp2171.outbound.protection.outlook.com (HELO NAM11-DM6-obe.outbound.protection.outlook.com) ([104.47.57.171]) by ob1.hc3370-68.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 13 Jun 2022 04:21:35 -0400 Received: from DS7PR03MB5608.namprd03.prod.outlook.com (2603:10b6:5:2c9::18) by SJ0PR03MB5583.namprd03.prod.outlook.com (2603:10b6:a03:28e::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5332.12; Mon, 13 Jun 2022 08:21:34 +0000 Received: from DS7PR03MB5608.namprd03.prod.outlook.com ([fe80::40af:d5f4:95eb:d534]) by DS7PR03MB5608.namprd03.prod.outlook.com ([fe80::40af:d5f4:95eb:d534%6]) with mapi id 15.20.5332.020; Mon, 13 Jun 2022 08:21:34 +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: d7a28907-eaf1-11ec-8901-93a377f238d6 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1655108498; h=date:from:to:cc:subject:message-id:references: in-reply-to:mime-version; bh=R9fY8n18h6g6SC38J+5bz83yfpSa/d201CTWahKP9Y8=; b=BLBbOO35NZaDpAZZI4XNjJpcrZ9JfI9JO+PJxogWiqZb+imw1LYblYuD 5E6lls4N+AnGv9JT9NgAFeez1pMJ4eHNcXteRxhfBEx091P2KcJlCuCl3 UUmwHArl1ZoMCcNkY6Ms3YO9dvgNWIaMGyveLKwFsFGoAQAlIgLVBn7qY Q=; X-IronPort-RemoteIP: 104.47.57.171 X-IronPort-MID: 73286110 X-IronPort-Reputation: None X-IronPort-Listener: OutboundMail X-IronPort-SenderGroup: RELAY_O365 X-IronPort-MailFlowPolicy: $RELAYED IronPort-Data: A9a23:wm3PHKDTJvUkMhVW/zXiw5YqxClBgxIJ4kV8jS/XYbTApD4j3zQBz WEfXjyDb67cYGf9LY9zboXk8kwH756BmNNlQQY4rX1jcSlH+JHPbTi7wuYcHM8wwunrFh8PA xA2M4GYRCwMZiaA4E/raNANlFEkvU2ybuOU5NXsZ2YgHGeIdA970Ug5w7Bg2NYy6TSEK1jlV e3a8pW31GCNg1aYAkpMg05UgEoy1BhakGpwUm0WPZinjneH/5UmJMt3yZWKB2n5WuFp8tuSH I4v+l0bElTxpH/BAvv9+lryn9ZjrrT6ZWBigVIOM0Sub4QrSoXfHc/XOdJFAXq7hQllkPh9y dxPqKOeUT0TGamchNVCCDpKQg9xaPguFL/veRBTsOS15mifKj7A5qsrC0s7e4oF5uxwHGdCs +QCLywAZQyCgOTwx6+nTu5rhYIoK8yD0IE34yk8i22GS6t5B8mcGs0m5vcBtNs0rtpJEvvEI dIQdBJkbQjaYg0JMVASYH47tLjz3CmhKmQAwL6TjaYW5G7Klwd765j8HOT5U/akfvh1r1nN8 woq+Ey8WHn2Lue3yzCI73atje/nhj7gVcQZE7jQ3vx3hFyewEQDBRtQUkG0ydGikVK3Ud9bL 00S+wItoLI0+UjtScPyNzWnpFaUsxhaXMBfe8Uq5QfIxqfK7gKxAmkfUiUHeNEgrNUxRzEhy hmOhdyBONB0mLicSHbY+rLKqzq3YHERNTVbOnZCShYZ6d7+po11lgjIUttoDK+yiJvyBC30x DeJ6iM5gt3/kPI26klyxnif6xrEm3QDZlRdCtn/No590j5EWQ== IronPort-HdrOrdr: A9a23:x5FoTq3IWhZwlHACqiwYhgqjBS5yeYIsimQD101hICG9Lfb0qy n+pp4mPEHP4wr5OEtOpTlPAtjkfZr5z+8M3WBxB8baYOCCggeVxe5ZjbcKrweQeBEWs9Qtrp uIEJIOdOEYb2IK6voSiTPQe7hA/DDEytHPuQ639QYRcegAUdAF0+4WMHf4LqUgLzM2f6bRWa DskPZvln6FQzA6f867Dn4KU6zqoMDKrovvZVojCwQ84AeDoDu04PqieiLolis2Yndq+/MP4G LFmwv26uGKtOy68AbV0yv2445NkNXs59NfDIini9QTKB/rlgG0Db4REoGqjXQQmqWC+VwqmN 7Dr1MJONly0WrYeiWPrR7ky2DboUMTwk6n7WXdrWrooMT/Sj5/IdFGn5hlfhzQ7FdllM1g0Y pQtljp+6Z/PFflpmDQ9tLIXxZlmg6funw5i9MeiHRZTM83dKJRl4oC50lYea1wUR4S0LpXXt WGMfuspcq/KTihHjDkVyhUsZaRt00Ib1i7qhNogL3X79BU9EoJvXfwivZv3Evoz6hNNaWs19 60TZiAq4s+P/P+TZgNcNvpEvHHfVAkf3r3QRKvCGWiMp07EFTwjLOyyIkJxYiRCe81Jd0J6d /8bG8= X-IronPort-AV: E=Sophos;i="5.91,296,1647316800"; d="scan'208";a="73286110" ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=IjaUUD3DZ18yWJteyM281O8OMxrAqjG0T+AIv7VQocfn9dwBcdatAp/UWMCFfTV+FS5/aNpbfubNnuEP74G1S6RXn18ITFoo/6jpzQBU1iNk3AS3P0zdB5wbh+X3qCaZ4A1TlMTZMWzA4RhzMuqZpPE6mDVKA4MadIx0Qug6sFJWvXbwPg+muAp3Ae2aC6BHWGD9olhYhCLmsJ1wCehRiHY9NFxdt3AD17MSPDpmYxorBZYb5yPD7kBUURduFVnPKRL6T1e5pnjHFsQNNrAcElWyS61NCWgxwwQnarAbGV7op2r6xQGD+Y4mbdhAcEN5WFziIBMf2vjDoFf5LlXB0w== 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=6oKQVHWQuTJ1uGEX+rVQcqENNtypqDEfE7TBGxyKO3I=; b=RyUQshTsIryXXWhqHnNJs1NdS2I4VxIMPmzFU9EDSFrhqVgxV3EXfo+fqI+073ccHTXOkuJkyi4X7NBaOGh9YxmE3alQ8ynmF9SFcjCnDKXNKNBke9TP1Ed8bmLXPHxod54an9q3PbRiONMwAujSLs7vwUuvVcl/rkxjpJJe4GDld2242Hz7dUiFWQxP0zz2q9kOGhJLbCfS3ClS2pthM2e4cC0YSBMIj6bccl4liIBkNyt9o4KZo/B5+7SS0ItOec8ZymF0vfML06qTgC3CdPVhGYRUx+2ysV1gKd1acopFn9Nfx5vKeh7ybc59bJ6l8/Y7WircJqSY7lnJcCJIGw== 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=6oKQVHWQuTJ1uGEX+rVQcqENNtypqDEfE7TBGxyKO3I=; b=oj4RsBNEfAK15mDo4/0QOu5euX7OIArmmjKajE+L9/qYkEb5JUG8/j6E5MRA4zu0eZF817KqhJguWeDcmc8T2U7AbDoFpvWaIwMki2pcom9LyvQBBYo6fmjTVODIGeVNDhPmkb3EKQakYM9PwLY8GONDucK5XyKwTS4dcnGM6tI= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=citrix.com; Date: Mon, 13 Jun 2022 10:21:29 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Jan Beulich Cc: Andrew Cooper , George Dunlap , Julien Grall , Stefano Stabellini , Wei Liu , xen-devel@lists.xenproject.org Subject: Re: [PATCH] xen/console: do not drop serial output from the hardware domain Message-ID: References: <20220610150651.29933-1-roger.pau@citrix.com> <3a462021-1802-4764-3547-6d0a02cd092f@suse.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <3a462021-1802-4764-3547-6d0a02cd092f@suse.com> X-ClientProxiedBy: PR0P264CA0153.FRAP264.PROD.OUTLOOK.COM (2603:10a6:100:1b::21) To DS7PR03MB5608.namprd03.prod.outlook.com (2603:10b6:5:2c9::18) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: e01d4043-bb09-46fd-ffff-08da4d15ba1a X-MS-TrafficTypeDiagnostic: SJ0PR03MB5583:EE_ X-Microsoft-Antispam-PRVS: 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:DS7PR03MB5608.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230016)(4636009)(7916004)(366004)(6916009)(83380400001)(86362001)(26005)(6512007)(8936002)(316002)(82960400001)(9686003)(6666004)(38100700002)(4326008)(6486002)(186003)(66946007)(66556008)(66476007)(2906002)(53546011)(8676002)(6506007)(508600001)(33716001)(85182001)(5660300002)(54906003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?NEIwbU5iVmUxaGlESDRveVN0cEJvR2kyaDRrWmhxYW1jWTFkM0F0Tnk1b2hV?= =?utf-8?B?QVVvT0dTK0F3Y1JLaTFGTWF1L3I4WW9zODUyajFaRS9LVzlxcVN3anpzaWlW?= =?utf-8?B?ZWlaZ0xaK1FaTUZ1NlFIdVQ3Y0J0UHpGNklCSXZLTmRSQkcyQVNWL2pScndS?= =?utf-8?B?WWRUdlFUS0ttMDY4aXRtRWlkVTBudDI0S0ZSbW41a3VNc0o2L2FZRFNkd3dx?= =?utf-8?B?MUtVRG4rOVVwcDJ1UnZicE5YUlcxN01nTWx4c3ZOK1NSbnFranY4U0NPSGgw?= =?utf-8?B?UkU5aFZIMkVPWXFDNjNyd1hBUjErYUNESXp5dU84K2ZubWM0djJYUjVSN1pJ?= =?utf-8?B?ZjNhZ0dPR1J0U3BkcDBJUnJDVFNRVkRJL3A5Y3BNR0YvMTZ1cEhFVHo5eXhE?= =?utf-8?B?d2hHREJUVmN3R2xmYTFRZ1hlSW9zdkxaZ1BYMVE3aXhtUUI3bllHMzZMbkdV?= =?utf-8?B?M1F6dzNGUlQ0VGZFd3l4VXhEZmswTWdBQkgzbjZXVUJlbjBVSlBrRUYrOW81?= =?utf-8?B?dmwzbDFWN1A0Wnd1Z2RsWFU3end3dkF0VWlOcEo5MlkzdktIRm4vM1pwbXdq?= =?utf-8?B?WGVtU2k2OGpyMWQxSDN3SE9EMFlpeXVDeklRNVF1cmZURldSSFcxbWJ1MVhP?= =?utf-8?B?a1ptZ0lUS1k2V1FVa3RZU3dWcEt3dU94YnFIVW1odEZGL0w5UXB0aUVzR2ND?= =?utf-8?B?RTU4d1JiYkVFUnREYk9zQXh1ZUJVUDJXNnRld290cVNiNlpVdGJaOUgzam1W?= =?utf-8?B?dmkvRUlLNjNBMm9GZ0NvKzREaGNPdHdXRUEvMTc4TXdVY1Fsb1d2VDNTY0hY?= =?utf-8?B?S1hybXh6R01mWFdoQ25HdzV3QS9qdDhtNXFUeHFpME5PdDF6c21XTDUzWXY3?= =?utf-8?B?MS9YYlVmRjJucFZxWSsyaWxZWC9wNHNwM1FsNFZkTjlXMWpCdnZxZE1GWGhD?= =?utf-8?B?MVhrbzJRbEtsRmZhWDNBaTBEMHJnNWN1TE04eGFMbHVmT2FkQ3Z0UmNYSEZ6?= =?utf-8?B?NEpUQ05IMWhxUjlqeVpkUENaVGtld0tSMUpHTmY1OCtoR3BIa1luNHdxSlRI?= =?utf-8?B?WkZTb0NqTlpJWHJGdVRwb3grMUdFV0tpTnlPNjQ2UHBWZFVsd0pQTkY5QmM1?= =?utf-8?B?MjFlU3pTT0tjVmNiUjRoU2JSSnRTSCtzbUZIZTVaM2NSTlRicitkMzhWYWZt?= =?utf-8?B?cFdLSVh4N1o1SjBFbm5MZ2ZCT2FOUXNCd0N3YWh6UzdxbTg0VXp2MnBEMFZB?= =?utf-8?B?UVlsOFA3TVBYUjlEMC9JWEl6Um1DRXc0amhFM3hicktJZ1RubHpPMGJzdWc2?= =?utf-8?B?SmFQQVZ0aWJJRWRjN24xayttdndUNFpWQWJuVmp3VUVrRDBkYTBxdjhhR0RZ?= =?utf-8?B?NG0wSExTVHYyQWNsWkw0aGliUmFzWlI1eXU0aVZRdnREOUZpVHNHc2VHbHRv?= =?utf-8?B?anBxbVFLcm1kSXVFUlh2c1kzR0Q5MmxjVEo5TUNGUEp1MmdLTHBPWTdiaW0v?= =?utf-8?B?NWVGekZvZ0hPVzFJNFlTZ0FrdjJ1U0N1eEg4MG9WaExyQkxyazBRUDQvQUVD?= =?utf-8?B?LzVCbVFBZ2JVRjFjMTJOcXFweVlZb2dKbnVzbVNJSjJYKzJ5UGgzT1VOK0dp?= =?utf-8?B?V3hSLzVjV3VwRDRYZHg5N29xUXhzeTcrYWdoM09yV01nb29PY3hINUgyb25H?= =?utf-8?B?YnpyNDBlTktKM2tXejhkRFo4L1RUOHRnN2J3OTJ2c2tqOFFjTzA2TXFFTTRZ?= =?utf-8?B?RXNmOEdTS1hRbjNsRWVYMlB1SGRKaU5Ydy9BcEhSYUNtaG9IQlA4MG5ZaHRw?= =?utf-8?B?WGhLdTZVSmEyL0E5dHpwMTFxekN0TU5UVm9CL1BnT0tFU2dKY1pMR2prcEZW?= =?utf-8?B?ME1OclY3dEtQM0ZYSXRMdFpUUWdPVUV3dUlwNWdtNzhLVkZYeEpkNDhOaldX?= =?utf-8?B?SCtPMGRQQ0FvRVM0MTNVbVNFa1R6bldGckRLYkhPZDRUS3RJT2drOXRqVmpn?= =?utf-8?B?YkFGVFJ6RGxwV1JxRjJSN0RCQkFFaWo5a0lIcWVmeXJJWHh4KytGWlorZFRt?= =?utf-8?B?UFM3NHdldFI4a1k4ZldMWmJLSlprU3haelF1ZnRUN2xHWUM5bXJFbkN6aEl4?= =?utf-8?B?S3ZwUGpsL0ZEYUd2U3pzSGkyOWg2Y2s5TVZEWUhCQTl5K0Z3dWNhMWM3K2p2?= =?utf-8?B?dlBUL3p0MWtKdUxPSHFEUFBVU3dxVVZpRFZKRmNWSlNiUFlSTnRNdUdZUHBn?= =?utf-8?B?bWtzTEFmTThRQW5FRFhnRkgzWGhIY1NEZkFadGg3MloyZm1NVzBCVlY2Z3dr?= =?utf-8?B?U0FFQnJhbFRCOFRVdStuSktOOXU1R212ZHgvWmVTbzQ4YWR0YzJ0dTlSbXQy?= =?utf-8?Q?bQ/0k9xwzTB6IYIc=3D?= X-OriginatorOrg: citrix.com X-MS-Exchange-CrossTenant-Network-Message-Id: e01d4043-bb09-46fd-ffff-08da4d15ba1a X-MS-Exchange-CrossTenant-AuthSource: DS7PR03MB5608.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Jun 2022 08:21:34.0517 (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: BkudsgFTz0+OBeqEMwxanKkpTVIxPsAWK1lTBDZbai+uZ6qPUfOy/bdDxxnRw9xHg0EKokT/C73efhm53l/hpA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR03MB5583 On Mon, Jun 13, 2022 at 09:30:06AM +0200, Jan Beulich wrote: > On 10.06.2022 17:06, Roger Pau Monne wrote: > > Prevent dropping console output from the hardware domain, since it's > > likely important to have all the output if the boot fails without > > having to resort to sync_console (which also affects the output from > > other guests). > > > > Do so by pairing the console_serial_puts() with > > serial_{start,end}_log_everything(), so that no output is dropped. > > While I can see the goal, why would Dom0 output be (effectively) more > important than Xen's own one (which isn't "forced")? And with this > aiming at boot output only, wouldn't you want to stop the overriding > once boot has completed (of which, if I'm not mistaken, we don't > really have any signal coming from Dom0)? And even during boot I'm > not convinced we'd want to let through everything, but perhaps just > Dom0's kernel messages? I normally use sync_console on all the boxes I'm doing dev work, so this request is something that come up internally. Didn't realize Xen output wasn't forced, since we already have rate limiting based on log levels I was assuming that non-ratelimited messages wouldn't be dropped. But yes, I agree that Xen (non-guest triggered) output shouldn't be rate limited either. > I'm also a little puzzled by the sync_console argument: If boot > fails, other guests aren't really involved yet, are they? No, but it would useful to get all relevant info without having to ask users to use sync_console. > Finally, what about (if such configured) output from a Xenstore > domain? That's kind of importantish as well, I'd say. I would be less inclined to do so. Xenstore domains can use a regular PV console, which shouldn't be affected by the rate limiting applied to the serial. Also that would give the xenstore domain a way to trigger DoS attacks. Thanks, Roger.