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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=mH9yQkQE1fqjRRX8L2lFXDS47yVPfUw4NppaJ8wSLnQ=; b=myjycmqTlsvzqFkwGCm/gW0MlP3As98v5Gdw3yIAnGj5NHATXHViNS0htc+E94frHYksIONFFikDUu8Jd4ohphFjd5DqeATQhP+k8Hi4sBIuv4I5IUUHwmIh6XAep8mW70dif62M6PSNWfss6U9Gtv6t4PbZiAGQKOsj70IpcYw= Date: Fri, 5 Feb 2021 16:43:00 +0100 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Jan Beulich CC: "xen-devel@lists.xenproject.org" , Andrew Cooper , Wei Liu , Tim Deegan , George Dunlap Subject: Re: [PATCH 02/17] x86: split __{get,put}_user() into "guest" and "unsafe" variants Message-ID: References: <4f1975a9-bdd9-f556-9db5-eb6c428f258f@suse.com> <13d1d621-21db-0e59-6603-2b22b6a9d180@suse.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <13d1d621-21db-0e59-6603-2b22b6a9d180@suse.com> X-ClientProxiedBy: MR2P264CA0015.FRAP264.PROD.OUTLOOK.COM (2603:10a6:500:1::27) To DS7PR03MB5608.namprd03.prod.outlook.com (2603:10b6:5:2c9::18) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: d6bae161-3f8a-4d94-0368-08d8c9ecbc00 X-MS-TrafficTypeDiagnostic: DM6PR03MB4219: X-LD-Processed: 335836de-42ef-43a2-b145-348c2ee9ca5b,ExtAddr X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:8882; 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X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?UzFPVXhHQmUvS3lMVytmSXZzbTRPTFd4NUtlNVhWbnZhbUtvOEliZHVMdkY2?= =?utf-8?B?OURiSk1SOFNIUUF1eHp1MjVqcmRoL1pKV1hJZXBSeWxuZkpSdFBzbUc3YXNK?= =?utf-8?B?YmFpSUFvK3BoNllpVHM1WDN2RDNyYm9rcmh0ZGplYmxjKzFlY3hUN0YvMm1r?= =?utf-8?B?bzZaYnZmS2RGRFZydzVQYUhlMytXcnBHZjREbGQ2TVlRN0RFcTlWQmtLTnRX?= =?utf-8?B?MUFlaWpUNWpLQWZkTzBvcG1HeVNDbVVoY3NvSHpyNmw4Z3JpWFBWbjYvUzBo?= =?utf-8?B?ZU0vaDluajFxVnpIbkNmRFAxOHVoV1QxRStkMVZJdyt1VFBOak9wR1ZGNzZj?= =?utf-8?B?UVV1VHE1S2RBZHBWWUVuZ0xqcnQ1dHZTNkdUSGlsYjNZM1RFK1ovQ3BoWktt?= =?utf-8?B?T1RFcU5JMWhESzlNRGRtYzMrT3BlMnBoUHVFM1BTS1Y0L3hsT216dllwZVJu?= =?utf-8?B?THNVS0JDS1BBVGlRZjVRMkJFZnJ6blN3Zm5saHNZNnVvRmtpTG95eVR5SXZS?= =?utf-8?B?RStFMU5VOG9LVDNHaGNyaGpNL1Q0eC9xN2hnSHYxNVU4M1BCb2s2eDBiQmpV?= =?utf-8?B?Z1YzeUlLS2FZU1VZVlZLOTBCeG95bkNJc1FlM2JEM3FZR0FoM0lMRkF5ekhz?= =?utf-8?B?RWZ5ekNCdFhKUEZQZUVML1RkN2dxTW5qK2V4SndwOVUwLytyVXFDbWtZalRK?= =?utf-8?B?MTIrMW83bStwQUxhK1RRZjloa2ZOa2JDY0hicS9zTmFDeDZLUXJ4OEJTRytj?= =?utf-8?B?MS8zeGg3b3ZyUjUwZHRCWml0dFN1S29YQ1FPVHRyZkpnRGJpaXB5WVFPTTN5?= =?utf-8?B?cDhwOXR0b0FKUDdua3FXem5pOXVQeEJ6Qm9RblBRSW0zY0UzRkVwNjFySGRo?= =?utf-8?B?Y0FkZmY5VkJ0U2NaSW5JeXhWVFFQaDJrcjFKdTY1WUVGcDZmNFUxa0R6RWds?= =?utf-8?B?V0gra0cyZWlsOG5iYVNCeEkyTTF5RlR5MzlYRFNpZEVJdmZkdmg2eEdYMFZz?= =?utf-8?B?QkF6bzZ4cnJ5K0JFL09PSlhXS1ZPSFA0S0NCM0tveEZpbEF5QjNKQnhic2FZ?= =?utf-8?B?YWo3TDR2UnozUXVnZ2ZYSlZia0VhcDlTYkprNCsvaFZ3QnNVT2NvaUdQSHda?= =?utf-8?B?Yy9Hb0lmejJkOVk2Q2xNVHFYMVQxMlViVTlvTnU3N09vZzkzK25rbC9URzh6?= =?utf-8?B?K0lTQjlDVGV6Lzc0VlltU00zTEx3TnVqNmJEcUN3NmcwQ090bGRWMEdqYVo4?= =?utf-8?B?aGRNRE1WRk1RRDJ0emJqeVZOM05MaUtNV2NkemMwNUppYi9Jc1NCSW9ORGxh?= =?utf-8?B?YlI4K3N3S0dXaHNaOUh4cXFudXJPbkl1L05sMmtPMU9xM1preVl0d1F4Mkdv?= =?utf-8?B?UDV4aEZxMHhaTGoyVTFCSWVkMDNwSGF0em1jQ29wdnhtRlBHYTlmcUZKRTRl?= =?utf-8?B?U2hjNE5paWhqQk1VMDQ5N0dHR3JuTGNhVHFGS3J5dkZpTGlZc0tTbWVZQVZX?= =?utf-8?B?K01Nd0FpK3NLSzlBMDRGQVVDUUFpcWVVdW1MaVpxYU1hZDNvenFLc3JNQWNC?= =?utf-8?B?WWtwNjNDNXlic010bFZFN2FKdWFqT0VBa0hDOHVTMnBzWktzejAzUzZVOFVN?= =?utf-8?B?Q1d4RUtTaFgvTGxWK2NUWEFxNmRoMGxKZXRGdFF3VHB1eTUxWXBwTEwyQitC?= =?utf-8?B?TXo5MjE2MnFRMHZyeTU2SnlrK3A1WGFtZDVrWCtGTDdpMS9uMStXMnRnME56?= =?utf-8?Q?1pafqDLEkuK0eW+hIm6gXGzHrT44rh/s6QHUckR?= X-MS-Exchange-CrossTenant-Network-Message-Id: d6bae161-3f8a-4d94-0368-08d8c9ecbc00 X-MS-Exchange-CrossTenant-AuthSource: DS7PR03MB5608.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 Feb 2021 15:43:07.7861 (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: mXLl0U6OpnQi7SmowwFMmgLheA0Jro8ZeOYOJ+AQtIIzzbER2OuKsaIEH9QPqQYBIR3LQhDT0x6SFi566R+6vw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR03MB4219 X-OriginatorOrg: citrix.com On Thu, Jan 14, 2021 at 04:04:11PM +0100, Jan Beulich wrote: > The "guest" variants are intended to work with (potentially) fully guest > controlled addresses, while the "unsafe" variants are not. Just to clarify, both work against user addresses, but guest variants need to be more careful because the guest provided address can also be modified? I'm trying to understand the difference between "fully guest controlled" and "guest controlled". Maybe an example would help clarify. Thanks, Roger.