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Thu, 9 Sep 2021 12:47:08 +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: 0d1cf57a-116c-11ec-b1b2-12813bfff9fa DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=mimecast20200619; t=1631191631; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Z66l6Ki7HWGDOqCU7aG0SHKqlUt01RaZXeqp5qD1xE0=; b=m6Tk5fxJvGBxJmc72r9s23/HhSBMRnMu/jOgeW0GQJrd7aOxrUeT67xbBopT+Y0hh6EWLa iGHFQt2NYDj6fRkC6Y6if+2q+E60G8BUE5m9X1FcNIAsQoSUZBJ86v9PsmFdakideu64k8 mZmrfZBwSCE9UEyR3ZoOBdTuMm7BcAU= X-MC-Unique: AuqBeqxtOOm188AUA2pyyA-2 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Xr/odA6fn4gJv8ArHHrLo+T7UhQ7FYG8MODcWShiU7zntA0W+q+UTR6YveRklPYMo+e8DZQ0yK3P3EjMdyu6k93KXCzWfZu28IHZE5Ln710lYgjtgO4tbmEY2vzPWNBilH60pLqqKk7zG3RsUovIGTA45gooLm2N9ZjWLRlPdgEWi8KttYBMgmHmYPGsvOOWKRSK2bC9wZNH9Vsmz+6ciecVN+js6A3OYzrK37yoX0pleY27aX4b34zC1lJzvseNYSch3aS28AWa/3nSIu4BnTvrRzq4oEQQRBOgch8jKbveJ/u8VCTBjy8ZFOqLfsOqSUbbiLY5gIhhXjxDzS8dlg== 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; bh=Z66l6Ki7HWGDOqCU7aG0SHKqlUt01RaZXeqp5qD1xE0=; b=IetjLL26D+sWXnOmopqO8e4IoF8ZJW+21eKPCRlPStChJk4gFytLLrvIIuyAe+T+Hlk+Bk6mp3JhgpaRtJJ2snN2OlntXFBV07pP04rwNulSnLD/gVXbttpD4u0RfleUKd00ddXrX0ps0DRPEqY0v7LtKoBVwGaJaOG+XqzuF0zGZypx8S8T7YmueGEZnNe8Faj20FwwJyDtBXhkwVDJWl0m76QG4fn+ZrD0FNMbcIml74xSaxai5rtdQlCMtLuD4O/qAkK7P0ag5Ts3gHU88dq4vq8jFlFC4eTHEeuHG9xN53kD+I/901SLxJeYDcJ8V0ZSXn4l2PG8bG1Uou6ouA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=suse.com; dmarc=pass action=none header.from=suse.com; dkim=pass header.d=suse.com; arc=none Authentication-Results: lists.xenproject.org; dkim=none (message not signed) header.d=none;lists.xenproject.org; dmarc=none action=none header.from=suse.com; Subject: Re: [PATCH 8/9] vpci/header: Reset the command register when adding devices To: Oleksandr Andrushchenko , Oleksandr Andrushchenko Cc: "julien@xen.org" , "sstabellini@kernel.org" , Oleksandr Tyshchenko , Volodymyr Babchuk , Artem Mygaiev , "roger.pau@citrix.com" , Bertrand Marquis , Rahul Singh , "xen-devel@lists.xenproject.org" References: <20210903100831.177748-1-andr2000@gmail.com> <20210903100831.177748-9-andr2000@gmail.com> <5366265c-d169-041d-f812-1c49260f6499@epam.com> <8f1816db-798b-15d9-7343-2199eb8f39e0@suse.com> <0e3942a5-9105-c99e-f15e-dcf35aae142a@epam.com> <5d0d345d-db16-f0c5-9a78-4ad5f4733886@epam.com> <5ffbd0a6-b34f-4de4-b316-2376211039f1@suse.com> <6db7c55c-93c6-7901-6097-687287463c78@epam.com> <73697ef0-85de-a530-7601-d8b1490ec5b5@epam.com> <6d8a4bae-cfed-07fb-d6e0-7587eb85069c@epam.com> <10bccd76-bbbb-1cb5-b9ad-4298014befd4@suse.com> <3ca10b3a-35c9-00b4-f736-293589d641d4@epam.com> <06560d04-6d71-bb94-20af-fc43cf686b0a@suse.com> <38669583-3e3a-36e2-8714-a4b6a4e10173@epam.com> From: Jan Beulich Message-ID: Date: Thu, 9 Sep 2021 14:47:06 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 In-Reply-To: <38669583-3e3a-36e2-8714-a4b6a4e10173@epam.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: AM0PR03CA0022.eurprd03.prod.outlook.com (2603:10a6:208:14::35) To VI1PR04MB5600.eurprd04.prod.outlook.com (2603:10a6:803:e7::16) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 9c8f2768-056a-4a74-e841-08d9738fefdd X-MS-TrafficTypeDiagnostic: VI1PR04MB6861: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:9508; 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:VI1PR04MB5600.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(396003)(366004)(136003)(376002)(346002)(39860400002)(186003)(86362001)(31686004)(26005)(66946007)(83380400001)(66556008)(316002)(31696002)(4326008)(66476007)(7416002)(8676002)(54906003)(956004)(6486002)(16576012)(478600001)(110136005)(53546011)(36756003)(8936002)(2906002)(2616005)(5660300002)(38100700002)(43740500002)(45980500001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?bWNWejd5b2lJdUxmNDdyNVNzSEtHOW5UVEVYYVM1a09NcnZyTHlidThBeFpK?= =?utf-8?B?MkxVcjM2b2RZRTlMdFVUd3pZZFZ1YU16N1I1dnB3emx2VENCWlRwaHVmcXJ4?= =?utf-8?B?Zks3cE5EZ0x2RWhkSHpTdzZ4aEZxU00vN3ZZUFlWWFJzbGJpMVhkemI2RmNt?= =?utf-8?B?NUQydlB4anFKcWtXNFhIMkREU0JHUmNBZmdZNWQxYnNoai96MFRiT3ZraXQy?= =?utf-8?B?aFlGRmIxbENCUWJTbnp5N0p3VFlGZElkSVZta0pyVlJaYXlaS2lWWUFkMWhL?= =?utf-8?B?WjZoRlFKSUVTdjlxRjFFVHNsdnNpMHByR2FxbkhHajh6UFdMOWRiUE9uL2Uz?= =?utf-8?B?M09pOUJUZkhVbVJjaGxDY3pnVzRyTGJSdUNqNEJCbmhOV2diWkRhUlk3TGtF?= =?utf-8?B?b2hYT3l2K1dSdjhRTEhKdWRsV1BreE51S0IwM3RuVk91RVNQYmwzUEFDT01P?= =?utf-8?B?ZnkwY3VTcmZLTzFmeTZWUGtCUU9zMDFseEUwVWlzS1dwQjdZdEY1OG9RMCtD?= =?utf-8?B?Yk85WjFEdWF2QXFIb0FtSGJyYzduMlpmcXNHcVBkbjhhMzNFcXE3N3AveFdD?= =?utf-8?B?SFBXcEJ5TFJSMWRDRmtjMWdIeXBxYmdRUWVmRlZWNFRXemJaMk5NVkNiSkJs?= =?utf-8?B?dkVLQjRsUlk1eHdnalYwNUtqekdMd3lpQk1vOFZyYmtjaktPcXRrREh0emZn?= =?utf-8?B?Z2U1YzNYSy8xdFhpcXN2M3hEeFFvbVJjRktKZFM2RmxjRGZnUHJ5N1N3U29V?= =?utf-8?B?dEo3NHk5ay9SNFpqQ1E1UlBkT0U1Zm5UbjFJUUFpNldKTW1XdDdkRzlqVGZE?= =?utf-8?B?amM5Z2NiY0laY3dEK0p5VmRzS0dkMDRERS9yRzF6SnZQWFdOYWNnckJJSW5F?= =?utf-8?B?UEJFSmZxQ3BTTDFSVlhtNEVPRi9RUmtQcnMrRU55ZmIvNGxwYkxIcEtYUGlE?= =?utf-8?B?Qi9YSytQMThNTFJ0akRtS3A5d1FEdWFmc1BUZzZSeEVaTFFrd2JNTk9MWlo0?= =?utf-8?B?emdNc2VjRG1CbFZVTVZHcVd4ak5RMHdUeHNaQ0s3aVBkdGVhdVZ5blhvN2Nq?= =?utf-8?B?OE9laFlHUStXZnhoVEFrWVc1LzcyUWNmY2Y5ait5aVkxbXFRR05yYzRGVjZR?= =?utf-8?B?QUU3eXZjVHRrQzBNRitEb0NSa0hwMTdUbDdidm0rQ0xwUVRYZGJURnhxNmQv?= =?utf-8?B?THkvK2hpcVNXU0ptRTJaWDVGNzNhSVVVSE9qNUovS2tpR0dGbHpKcno3bGF5?= =?utf-8?B?RkliQWkybGRCZzdHM0pGdkNadlZvRjVZYjREc3M3TnFvRHpCRzU5WWtjbkUv?= =?utf-8?B?d0V4NkRPQnJ4OVJVTWRDb2hKZU1GMlFzSXlQNkU3Sm1NOGVaRGJHUzdZZzBk?= =?utf-8?B?NHNUaFNLbHNIRTh5NVBrd2sxQThIbmM0WnhCWU5VMHZLT1NVWFhibGFPV1dx?= =?utf-8?B?SmN2Yk5PSXFXc3A2NkZXTDBQSGZSbHFrMExMYzdBL0U0d0xtc1hLcUFxZy90?= =?utf-8?B?Y0V1L0VNRFB2SklrS2NTcDdIRFUrb3BML01lOE5XUVpjbGJrTTE0U2NLTjZn?= =?utf-8?B?NEQvaEZFV05BMnBYUXJaSFU2TzlnNFJzcmtOdy8rRUdySEsweHUreVVSdXFH?= =?utf-8?B?cW8zZzh2RFNGM2hxZkVac2V2dC83c3E0NE14d3FFTzVpVlFSYmZXQ2t2bE1z?= =?utf-8?B?bmozQlR5NUVtdVlBTGZrbVUyUU1HWkw2ZzdFZHp0eHljd1pvTEw0Mkt1M05x?= =?utf-8?Q?4xad63fNd72Ab9bmFtbn/BKAzWBIuqd2Abjp5PJ?= X-OriginatorOrg: suse.com X-MS-Exchange-CrossTenant-Network-Message-Id: 9c8f2768-056a-4a74-e841-08d9738fefdd X-MS-Exchange-CrossTenant-AuthSource: VI1PR04MB5600.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Sep 2021 12:47:09.2550 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: zWlwK8uQ9HuBMWBlwonu+NOEVBI3EevXcV4KcD5oA1u/MEe7eq9uDGPN/LAVRRL1cOvxOu5D2v7szynz4wZ17w== X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR04MB6861 On 09.09.2021 14:42, Oleksandr Andrushchenko wrote: > On 09.09.21 14:53, Jan Beulich wrote: >> On 09.09.2021 13:48, Oleksandr Andrushchenko wrote: >>> On 09.09.21 12:21, Jan Beulich wrote: >>>> For the bit in question, where the goal appears to be to have hardware >>>> hold the OR of guest and host values, an approach similar to that used >>>> for some of the MSI / MSI-X bits might be chosen: Maintain guest and >>>> host bits in software, and update hardware (at least) when the >>>> effective resulting value changes. A complicating fact here is, though, >>>> that unlike for the MSI / MSI-X bits here Dom0 (pciback or its PCI >>>> susbstem) may also have a view on what the setting ought to be. >>> The bigger question here is what can we take as the reference for INTx >>> bit, e.g. if Dom0 didn't enable/configured the device being passed through >>> than its COMMAND register may still be in after reset state and IMO there is >>> no guarantee it has the values we can say are "as host wants them" >> In the absence of Dom0 controlling the device, I think we ought to take >> Xen's view as the "host" one. > Agree >> Which will want the bit set at least as >> long as either MSI or MSI-X is enabled for the device. > But what is the INTx relation to MSI/MSI-X here? Devices are not supposed to signal interrupts two different ways at a time. They may enable only one - pin based, MSI, or MSI-X. Jan