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Date: Thu, 29 Jan 2026 10:19:52 +0100 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Jan Beulich Cc: "xen-devel@lists.xenproject.org" , Stewart Hildebrand Subject: Re: [PATCH v2 4/4] vPCI/DomU: really no ext-caps without extended config space Message-ID: References: <58091dc1-7bda-4536-8200-2d0a5679d4d1@suse.com> <96e90685-3321-4884-8fe7-f083c25ba7ab@suse.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <96e90685-3321-4884-8fe7-f083c25ba7ab@suse.com> X-ClientProxiedBy: MR1P264CA0185.FRAP264.PROD.OUTLOOK.COM (2603:10a6:501:58::14) To CH7PR03MB7860.namprd03.prod.outlook.com (2603:10b6:610:24e::14) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH7PR03MB7860:EE_|SA2PR03MB5900:EE_ X-MS-Office365-Filtering-Correlation-Id: 074fbde0-ccdf-41bc-fdfb-08de5f17913d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|1800799024|7053199007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?cWpvUTFteDkxUWhnVjF6enFURWJtYlpCOTZaWWRHU3VYQVFVY1N5TlJWUU9J?= =?utf-8?B?VWxoTFI4V3h6TExFNVNkeFlYRyt2dVBnWnBUaGpDQzZWT2dORDFGcGhsTXc4?= =?utf-8?B?VFNWWWJDQkt1aW1SQk16dGdzTkZCdVFGOEVYTFlqQWFaUTF2RE84WkExb0NQ?= =?utf-8?B?ZVU5M3JjQ3Z0ZlpNUDdNblZ5RHNvMXFKcG1TZGRZb29LRThlSEVkckpPdHpJ?= =?utf-8?B?VTBDSGdSYkx4RW9yenBZbkpCMDM2eFBhMjlIZ0ZUVUxCdnRlTlV5eXFvYkVr?= =?utf-8?B?M1YxSUhvMGcxTWZMRG0zdGd2bFBnOWhtU0N0STRMY0cvNDZoRlIyZ1B0WG45?= =?utf-8?B?Vk5nTlVkajljVW1yd0FDRmcrME5MenlTZjEyUGxCdTA0cGlKV0hxclR0VDJ2?= =?utf-8?B?aWhxWVNTTmlNSGpCL0hJeVpkVDhrcGZpMmorcjliUERaeDdDeUVIalpDc3Mx?= =?utf-8?B?S3JuV3pqa3pXMGo4RmVzMnJBbTRGakFKbDB2VEorK0Q4Z282SHkwWm1iRzNC?= =?utf-8?B?Znp0bTBpMzdJQi9XNG00czFBTUUwSm1hWW5qT21Bc1dHQTRGaHhSS0J0SDBv?= =?utf-8?B?eHpDQ1JGK1BkQ2JZNWxlWDJ0czdKNWpuMmRoTElxOEdIZU80T1VEMXIyR1ds?= =?utf-8?B?aDdjdWRkZWxGT3UyWGx6NUZoNzN6WUtuaDVaL0pENWhVQ2hrakdMemMwZENR?= =?utf-8?B?Q2lnOThVVmFSRE41cU5maVJYdGUzaHcweEJGU1BvNVFkMXBNb0Q1N21aWktH?= =?utf-8?B?UmxvMzJhdURlbU9YWXpOSGlHNjZ6aGFGSHdhWndMYzZ4ZnBHWUNSd3BjYXF0?= =?utf-8?B?UkpDVkM0MU9MZ1l3Tm5Gbk5hK3lEend4ZDRkZVdmMldpUVQ0N0llU1FZbG84?= =?utf-8?B?VUxWUTgxTDZFU0hhMUxNZFM4ZTg1VmdDRTFOdnZJcFA0ZTdEVHRqQVNNUG1p?= =?utf-8?B?MTc5RWxPTFNvTGlMb1lhVEhvSHQ0VDE1VElXWEFSZnpZV3FpZUk0TjF2VG9i?= =?utf-8?B?MGc3czlpc0U5TDQ1VkpmR3NRTmt0UkJGUSs0czUxR0xRa0pVSzB5bDhucXkw?= =?utf-8?B?d3JibTEyUHVBemxaQ1M0RkV3ZnJxdG1HZmljcko4MVNJZStZY3pWbnU3TUgy?= =?utf-8?B?aVUrREFGTXRYTTUxdlJBazBQMjNTdkdCNUF3VzJvSTNFZlFSSjdWVnhab3Bx?= =?utf-8?B?d2tOcEM0WHN0QjFpTjBmTjBlMHZMQkhZbi9aM3dwMWJFYnFpaUhWWlBPcTBs?= =?utf-8?B?OGxEd0RGTmJsZlMxdWV4eGhCU0NvUFlBTHpVMXhFcGFsZUNhZkJaNVFjc2U5?= =?utf-8?B?VnhhdjV6NmlXczA3SUN1QksxUnA1a3RBNTU4dy9QQU9PZWt0QUpKU285R0pO?= =?utf-8?B?dnpwdU1nK2RFa21Xd3d2UGZRUHUvRXlaeHo3aDhRRG9jUlNRdERZd1hhemNp?= =?utf-8?B?ODdwdzNPSlFYMHRGUjBnbTVyYnpiRVkxYjFxbUJvWTMrVlJTQVJNNFFjdXAr?= =?utf-8?B?czRXRUhWeStIbGFidlhYTzRDWHV2WHNkQUE1d0pIUWJEV1BVWmdWbm11SUty?= =?utf-8?B?MkNNc01sZWlreEQ2bmJvYXRiZTBwWFhGemRwYVU3aDNvY05OUTNEaDhrcTc5?= =?utf-8?B?emRnMXd5TmIwN3p5WG0rN0RvOFV1VHZabjByZnQyRjhxRldFQjNsbkMyNnFz?= =?utf-8?B?Uk5wQkRoZVJGMlMrQVZoUWFPOEdFZjBVdnJvN2ZZdmM0Y0gyY1NYUElZZjll?= =?utf-8?B?WTFXYVhCam5Iblk2OHpwY1V4ekMrRlhrV0JGcVV4UFBHR0tkRFd4RUpaUW8r?= =?utf-8?B?THdrMkUyZWxab2o1eXM1SVd4ZXhWM3cyekJsT3V6TTRMdU4xa3o1alEwLzNa?= =?utf-8?B?OFN5a1BRZHV5UDBVN29TRW4rYTdWbE40eE84N3h3a0h0RmZYSzFwelhYcVpp?= =?utf-8?B?T0ZPOXBDeTc2V3lBd2NJL09BbHNTQ0UwYUIvVmJBdVd4WWRrWGxIRm42VEF2?= =?utf-8?B?dXdCTHFVUEFRNVdFQzEzcjlWNjl5RmdtWEhjN2czVFJzQ25MbmV3c0NiWHBZ?= =?utf-8?B?V1B5YjJRZ3dnY1FJRGE2RzhWZzM5RU42eXZhMSs1a29Zbk8zTE1PRHRHVUh5?= =?utf-8?Q?n12c=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH7PR03MB7860.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(1800799024)(7053199007);DIR:OUT;SFP:1101; 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If it doesn't, read-as-zero isn't correct; not > getting this right may confuse functions like Linux 6.19-rc's > pci_ext_cfg_is_aliased(). > > Fixes: a845b50c12f3 ("vpci/header: Emulate extended capability list for dom0") > Signed-off-by: Jan Beulich > > --- a/xen/drivers/vpci/header.c > +++ b/xen/drivers/vpci/header.c > @@ -830,9 +830,14 @@ static int vpci_init_ext_capability_list > unsigned int pos = PCI_CFG_SPACE_SIZE; > > if ( !is_hardware_domain(pdev->domain) ) > + { > + if ( !pdev->ext_cfg ) > + return 0; Don't you want to possibly put this as a top-level check, so if there's no extended config space we avoid doing the PCI_CFG_SPACE_SIZE read for dom0 also? Thanks, Roger.