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X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?ZzFsMHhVMTlLQmllc0daTTlzaDZZM2lwK0NUb0hCNTFKbFYrVWd6c0h2RDNX?= =?utf-8?B?TmNEaXRXK25TaHZtOEJBMkFGcEpNd3dwUXllN1lZVVpWV0tsWHJVR0p3eUFj?= =?utf-8?B?N1ZrY0JuWnE3SHBzK2gwTmMwTzlzdGZzbTR3Mi9OQVlGR1FLY3BPR1B2dkVh?= =?utf-8?B?djRJd1R0eERud240cUR6RU5XUWpxdWpjck9nTDd6TzVXWFpVWDJDVzZESjk4?= =?utf-8?B?MXhIWDhIQ0ZxanJsNVg3RmhOMEtkalh6a2hwMWZqR28wTW5xNmxicUk4MUsx?= =?utf-8?B?RzIwQ0czbkRkd0VUSWhFTFRPQkIwTnFsUnBYT3NhL1h5clNVWDJUSEFXZVdz?= =?utf-8?B?eDhPbytEVURVSFhwczV1KzdTSmJ0M3hKUGlZYWxpYlo2aFVnWXJXc2x1bGdD?= =?utf-8?B?Ti82em1Ea0Y1cXFuenVTK2t6NlRpQmsxWDczbjN5Y0VGSlhiWnBKWVgwOU5l?= =?utf-8?B?S3N5dHNwblFxdGZFcVVaU0dxOHdZY0JyWldNVjFtaHFMMFNOZzcrNkc3MjJT?= =?utf-8?B?WGxyYitJeXZXdjdrL2Voejh2M0tNR1pINGs0OEdUT05jUkROZXRLVitYSUMw?= =?utf-8?B?RWx1MWVqVnc4K3JmeXFWUEVCRmZFN296M0tIUFh5R25vOTExUWhJNzRkSnZ0?= =?utf-8?B?ZHI1VER3ZDUrTFk1SG9UakU0dU9pMnZOaXdka2NZdWtzRDJINVgzbWJmSDlq?= =?utf-8?B?ZHZ4OXRmSThVSGhtVmxndS9qRmErcGpZV2FDK3hSM2JqZ3oyakZsYUxvaHhD?= =?utf-8?B?QnZCQTR1NExOTnlCMW1oYjllRTczZS9lc21sdXlxeGc4RjkvakdmUEZQYldi?= =?utf-8?B?T1E4WVZCK2xsV3BIQ3FtdG41cmMvaDFwMW92UERJd2tORW0rYlhEYnVWdHRk?= =?utf-8?B?K3RtQlYzUWhHS2JFOGJUM3FPTzZ2aFZPSHhTUnBWQjBvUVV6Q0hjYWd2Ukgw?= =?utf-8?B?UXB4a1VvaE1KSG9lWWM4M01jMlVSNXR3NDlHQ2g1Q0dack5OQnlvNmtLNVBv?= =?utf-8?B?MDlJMFRDZUFWbXluY0tTc1JZaUVSVjdQSVp2UFVhT01URDBzNTJ1OVVhdnMv?= =?utf-8?B?ME1kc3BqMnlqUjl2eUhpbUowMXNsTk1kREl3S0pKb3VMVVd1bStsZnRLWTEw?= =?utf-8?B?N0FhQXFmSDJhbVpFbGhQNjVyTWFsZ0JObVFyN3lCNk0vWGhheFZ1RHRneU4x?= =?utf-8?B?ckFROWtua2J1bllwZHkvSnhoT2tLUEJ5b1NaTVQ4ODF3b1ppTVQ2eEY3b0Z5?= =?utf-8?B?MlEyak5RTTRldVdUejBwRUh3TnNiQXhWYUJkNld0YkNFNEswRXdlUFQ1MFFk?= =?utf-8?B?QlY2dloxM0VycEw3cUJvOWhidzY2akVjMVpONnNvSUptaEQza3ZUUE1GYXFZ?= =?utf-8?B?WXdJZHFFK0hQTWRsZ0tkcXV1dk5VTWtyOUxUSnpwN2tjVjh1QlZUMngyWTJk?= =?utf-8?B?eDRSdUp0Ly9qNmYxTVBpd0l6VHBmQ1R6S1VpcjFRSE8zQnRpUXlFdTBBa0N5?= =?utf-8?B?LzYvWjlJdUNMbWVVTTJNR2gxMVc4K0dZQXp4S2FGTUFVTEpOUlhXdHpLNmlI?= =?utf-8?B?bDFEZjlsVEdmbGdUTUkrcUppVTdacnhlbmNPdmYvSWNPZjNJRUtheE84QXgy?= =?utf-8?B?M2xVY21FMUhKWWkyTWE5c0YrREszNmY3NHYyNDNlZVBVUkhmV0FGSVhXY1li?= =?utf-8?B?SzNVdjM1SFl0dHZ1ZmV2c2RPVkppd29SWlNQL0xUUlNvbU5UektYUzcwU21G?= =?utf-8?Q?KiTsXIqT2wEUMJHsmy+fsTp1zFj3vjEB+gWBLe4?= X-MS-Exchange-CrossTenant-Network-Message-Id: d32732c2-be5d-4cef-acac-08d90e5fc525 X-MS-Exchange-CrossTenant-AuthSource: BYAPR03MB3623.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 May 2021 18:17:54.3697 (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: MC41fg+Oht054VjBgW87RRCdIsB3isS2wzI1UqBfTr2RH0vV6kXN7/QPwjL/frrrDEOVu7C6MVJ0Uprlcl739FecMdK0VcPUUI9151HupZA= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR03MB3430 X-OriginatorOrg: citrix.com On 03/05/2021 16:39, Andrew Cooper wrote: > We're soon going to need a compressed helper of the same form. > > The size of the uncompressed image is a strictly a property of the highes= t > user state. This can be calculated trivially with xstate_offsets/sizes, = and > is much faster than a CPUID instruction in the first place, let alone the= two > XCR0 writes surrounding it. > > Retain the cross-check with hardware in debug builds, but forgo it normal > builds. In particular, this means that the migration paths don't need to= mess > with XCR0 just to sanity check the buffer size. > > Signed-off-by: Andrew Cooper The Qemu smoketests have actually found a bug here. https://gitlab.com/xen-project/patchew/xen/-/jobs/1232118510/artifacts/file= /smoke.serial We call into xstate_uncompressed_size() from hvm_register_CPU_save_and_restore() so the previous "xcr0 =3D=3D 0" path wa= s critical to Xen not exploding on non-xsave platforms. This is straight up buggy - we shouldn't be registering xsave handlers on non-xsave platforms, but the calculation is also wrong (in the safe directly at least) when we use compressed formats.=C2=A0 Yet another unexpected surprise for the todo list. ~Andrew