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X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?Qy9RYlpXQWdqK1JQd1Q5bDJKQ2hTV2lpYm1zSEtkWmZ6bVo5cHpiUE1nSk9L?= =?utf-8?B?Z05WczlUTzJHWmpFUHo4WFJBTzVkajdMQ05IOG5tVnlJUEVTc29XQjhMWWpj?= =?utf-8?B?QklkUkt6UHpJMHFpdlNmUGF6dXQ2K1FQYkFXNHF0ZWxwb2hONkpaU1JwOEcv?= =?utf-8?B?TExBaitnQUhTTWFMYzg5S0Z1cXdUR2swaDUzTGQ4c2xsYWxvZzBadFBqYVVy?= =?utf-8?B?NTJ6cjBDZ1RmOUhXRURUYlJTa0M2MHhHaTFPSmVob1JNd1dQZDduRGZSaUpq?= =?utf-8?B?YVIvbGdzUytycml4RThrMkQxaFNId3ZsM2hMdFFJSXZJUWIwS1RPWklrK2lQ?= =?utf-8?B?SnpOU3dDSDYzcGc2UkQzcnl4TW5SRkZkZUdFbVpTdEJDT3Q2cXMyWnIzQjc4?= =?utf-8?B?a3RpSVZUTWpoaDdkdDdTWm1UMS9oU1puQWNCUzMyYWw3WE5EUWZMNGM5UTAr?= =?utf-8?B?L251bFlkdEdLTkdlUVN2My9iNHpsb0E2cDBKa29nQnNvN2lnSkJHUUh2MTQ2?= =?utf-8?B?TGxsYm1qSnpmZDZGZi9nYTluN1MwZW1GNTlzLzJlMTF2MXp6RXltbFdZKzZn?= =?utf-8?B?aHVDTXZwS2NkTnNVS0xNN2lTUS9SRXFCS0t5RTFGUTNpbTY2NjFpNjBxMlFa?= =?utf-8?B?R1dxK2dLUVMrYVF5SEV3OE0vcVBpUU1WVUJralFHcHhKSld2NzJLWmFlZ1Ro?= =?utf-8?B?cXNKdW1rbVB1dmNJWGNNRFhBbHczV2FMdTRjc1dsN2dLNU5Zd05ZK0cwVTgx?= =?utf-8?B?MkFRZGpiLzFSTExBZWxlMWZwc09ab3diZTNDRS96eWkzcjNvU0hocE1pQkdB?= =?utf-8?B?OU1Td0pTMmdVMGNRdTJzUm9SejRsNlZMZDlwbHozU3gvZUlvb0VCZlZrVHhk?= =?utf-8?B?SVNlU0lSTzljK1pjNkx6WFpKMXZSQkxXYlNFWDhOcDlKTGFBajFZTXMrUlRz?= =?utf-8?B?WlJDSHNCNVBCMURiV09zOXRnbEZTUEl5WXRaMnVBTHJSYmk1WURNRFhCSWl5?= =?utf-8?B?NnlBblFsS3VQaHNENDM2WjFkNzA4cU5lc1VqNmJKSkoxMEU0OU9XZzJGMTFT?= =?utf-8?B?cW9HaUxzVk43U3JjamNMVG9KdGhWSmFyNHVBSkpPWjhnZFpIalMwbGxQeGgr?= =?utf-8?B?VVNjMXlqN3RXMFdrYWpXdnIxUTlzN3Jsd0JseE9vbzJ0Y0Y2ZEpQK1daQUFz?= =?utf-8?B?SC9FNzROWjVpckpVdjFnS0ZrdncvVjlrZkkwTmZaa0RZQjZSWm05RnZPU0hq?= =?utf-8?B?U1dza2JSSWFJVDViT3JuZmVyZmxkUjZWYTV1ZGFXUW9DOUZyMThDbWRpNFl6?= =?utf-8?B?S2lzZlphcGM3bkFQWDVBTERqS2pBQm1uSFRabmdsVEVNNXlxcHlFQ2p4VGtS?= =?utf-8?B?SmNGeHc3WW41aGlpdWZGTU5vZVVyYjI5MGhDSWhDakxaMG9mZjRwRVpkdXU2?= =?utf-8?B?ZFFFZ004WDRHSGZEd3pzZDVQTWs4aWgvcjlpaE0wUkROajZVRGlWYkFkUW1N?= =?utf-8?B?ODV0MGRNSTNqTlZhSXAwdEFhcDlnY2IwMWRyVUw2K2g2aE9BZkJYTElEaHBi?= =?utf-8?B?aW5SdjUzYms2WkJPY3owY3ltZWJ5aEZ4TlRsRWlJMTB1M0dENjYvMUk3dXhv?= =?utf-8?B?aHZmUlVLYkVhRkh4Sm9yRHNCamZZUGxITTl6RXh6cituV3phSVdMaVcxZmEr?= =?utf-8?B?d3F1K2w1WERvajYvOEFHUHFXV3VSVndEOXJXdkQ4UytpZU01SDhKUlFBN1lT?= =?utf-8?Q?1yjznkP5TT2MALvmkIpixrS6Krk0TV8/vFraP5s?= X-MS-Exchange-CrossTenant-Network-Message-Id: 159c06d6-f7c7-4300-c869-08d90fb37331 X-MS-Exchange-CrossTenant-AuthSource: BYAPR03MB3623.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 May 2021 10:49:25.7709 (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: rOql2WliqxDLE2hzv3Um8M9z4ZP4Dm4gOguJZSMpX2v/oyynQdTrnfRH6jodY6z9V12q6b4YNqDq81ASrP70LpLBa8nu/ajAyb1J4Rig3W8= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR03MB4360 X-OriginatorOrg: citrix.com On 04/05/2021 09:42, Jan Beulich wrote: > This array can be large when many grant frames are permitted; avoid > allocating it when it's not going to be used anyway, by doing this only > in gnttab_populate_status_frames(). While the delaying of the respective > memory allocation adds possible reasons for failure of the respective > enclosing operations, there are other memory allocations there already, > so callers can't expect these operations to always succeed anyway. > > As to the re-ordering at the end of gnttab_unpopulate_status_frames(), > this is merely to represent intended order of actions (shrink array > bound, then free higher array entries). If there were racing accesses, > suitable barriers would need adding in addition. > > Signed-off-by: Jan Beulich Nack. The argument you make says that the grant status frames is "large enough" to care about not allocating.=C2=A0 (I frankly disagree, but that isn't relevant to my to my nack). The change in logic here moves a failure in DOMCTL_createdomain, to GNTTABOP_setversion.=C2=A0 We know, from the last minute screwups in XSA-22= 6, that there are versions of Windows and Linux in the field, used by customers, which will BUG()/BSOD when GNTTABOP_setversion doesn't succeed. You're literally adding even more complexity to the grant table, to also increase the chance of regressing VMs in the wild.=C2=A0 This is not ok. The only form of this patch which is in any way acceptable, is to avoid the allocation when you know *in DOMCTL_createdomain* that it will never be needed by the VM.=C2=A0 So far, that is from Kconfig and/or the command line options. ~Andrew