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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?eHhWbjBuaXFJZzRUbm51cWxsVG9md3ZaRkhiNmlzM3FJN0wyU2xHK1JEVUJ1?= =?utf-8?B?QUFwakJqeVdqZ1daTHkwQW5HWVpQdHJZWHJ3OUJTcEU2aVc2cmpTVjcvK2wv?= =?utf-8?B?QSthZ01ZRHRkMk5tOVREVk4yZXJyUDdkOGl3ZTJIQ3ByeXppR2RFV3YxRXVR?= =?utf-8?B?VjYzaE9PbUk2a1FFNzcrc0h2MVI5MDRZc0E2Q3kyaTJkeEc3bnpzODZ3RE1p?= =?utf-8?B?L3pURVFlQ21FbVpVSW5tQUIzOXF1bk80TUdGb0VBTi9zajBnMUx1UFlrYzRB?= =?utf-8?B?MjA4Yk1hdnY5SzBNVUR6WDBETU1LRE04emhtcnphRXJISVo4VzF0eFlUWjhZ?= =?utf-8?B?U0o3ZEFuclZxOUZLOCtBL2s3Sk5WL2M0TTJ0clJpb1FiQk11b21TdWhuSE8r?= =?utf-8?B?S0QzdE1icmxBMmwxU3VIb3psZy81bW5wdUhmUEJUdkFMVC92cXVMa1VMNmpX?= =?utf-8?B?NWs3SEJ6SVhwTENhY0RFbC92bllhSUpUVVE0TWxSYkN6QnozcXQzQmxvTHhv?= =?utf-8?B?bVgwcjZ3K1R0NXJKTm5FNjlndVF0VCtsZG13ZG9JeUU0ZGpWMFZGK2c5NjZN?= =?utf-8?B?ckliWXFpUkE1SE11bVlqV1FuR0JZcFR2ZDZIdTk1aVkrVUFNeENpOThUUXU5?= =?utf-8?B?RDYzUHVmdWkvakJ2bTVmV1FYQnM2YmhZMXdjZXFxRHhrSllHK1dMcUFoaUo1?= =?utf-8?B?S21xaTJhZGRDRDJhdGMxSVhkKzRnL0VIeGhqWE9EMDB4MWFQZmkzSHB0SVFQ?= =?utf-8?B?UEl1aTR6Rit0Z1cyYVFvQVprT3hjNGt0TWRnSWY4N2dwbVhnVFBmSWZvbllq?= =?utf-8?B?TVFjQVhvYmtQVG1DOCtrVkQwN2VpZFV3bG4zWUNYNWF3RHo3ZU1YNWZJb0hr?= =?utf-8?B?Rzl0MnErZkEwc0lYekxBQU9KNFNUMWRvL1dlYWNKSzJGVjQwdVBpa2xuNGxY?= =?utf-8?B?TGtVN0dQN05JeDJYdEwzakNEYURxd2l3YjdOQTEwNWhqUzVBZkpCeFFWS1dm?= =?utf-8?B?NUZ1VllJbGdDclhpcFl5dVpCemtjcVBBaTVTbzZpdTBBV3R5Qk9CQmVSZ2Iw?= =?utf-8?B?NEJiU0xvWjN4YStQWHhyS1dxK1RtMk1LQ0lNZ3FtSElLYmtHbzZMNFZTd0RT?= =?utf-8?B?SHlnSTNBcXZiNFR4U0lDcDhOd0NNNFAwYmpUSjZ4RlgvalJ6WTYxQ1JoQWRM?= =?utf-8?B?cnp5STZ2Mmd4Rk1VYTcyelh5a1dqcXlsN2x3d3hMUzBveFM5Uld4aEFUUmNs?= =?utf-8?B?ZDJiUEZtZFVicVVrdHEyVm1Vb2RDRkFvUEozbWVkb1NqcmRHTUhiUDdDOFIv?= =?utf-8?B?ejgxUVRWM1N3eWVvZkdKdndWVDZsL2NOZGZ2VkVuS1NlMTVGT0t1TC9yYnB3?= =?utf-8?B?MHEra3dmZm81YTNPU3hNNFd4WUFxaVArOVo3R1FySExRVUdmZWlKVXVLaWdi?= =?utf-8?B?aEh4VzRQbU5yMHY5Nmw2QUQ2eGRxMTdtMjN0RXZOSGxVQ2FlSUZIcHBVUE1U?= =?utf-8?B?eVNNWkZZRllJYmtPbnpXRWd2WjNqSjFUcklnRFFNT0w4ZTgyeEowN2YyeDVP?= =?utf-8?B?LzRhbVdaYVlXMkRFSFl6OFhJMURuYkYrRGhWZU1ua1RIeFhvdmRoM0RyT0RV?= =?utf-8?B?N3FuUVRGV242UE5KcHJIRm5aZ1FNRzQ3U3hNRDJ2VUl1MG9hcHFEQVRkdFdN?= =?utf-8?B?NVZwYnIrOEtIaTNWOUVLQ3p5MDVlWGtJMWJscUZEZm9waUF3dDh3b0lyL1Fx?= =?utf-8?Q?N3HYQHZHUM6um0vSiIiyXKGLb5Ywz8MnTncv0b3?= X-MS-Exchange-CrossTenant-Network-Message-Id: 99d2d192-42a5-477d-5849-08d984e7efb0 X-MS-Exchange-CrossTenant-AuthSource: BYAPR03MB3623.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Oct 2021 14:30:14.7482 (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: 8G14BTS4nGz/BVVwbZUXqT9Ff30lSekRrkJHs2Z/0knL04JZyiBwlC3+dKXha29XzD1S1yK6bD+UA+wsDss3s5tHnQxI1AP27WafXIFLOHs= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR03MB4966 X-OriginatorOrg: citrix.com On 01/10/2021 15:19, Jan Beulich wrote: > On 24.09.2021 21:39, Alex Olson wrote: >> Inspired by an earlier attempt by Chao Gao , >> this revision aims to put the hypervisor in control of x86 APIC identifier >> definition instead of hard-coding a formula in multiple places >> (libxl, hvmloader, hypervisor). >> >> This is intended as a first step toward exposing/altering CPU topology >> seen by guests. >> >> Changes: >> >> - Add field to vlapic for holding default ID (on reset) >> >> - add HVMOP_get_vcpu_topology_id hypercall so libxl (for PVH domains) >> can access APIC ids needed for ACPI table definition prior to domain start. >> >> - For HVM guests, hvmloader now also uses the same hypercall. >> >> - Make CPUID code use vlapic ID instead of hard-coded formula >> for runtime reporting to guests > I'm afraid a primary question from back at the time remains: How is > migration of a guest from an old hypervisor to one with this change > in place going to work? I'm afraid its not. Fixing this is incredibly complicated.  I have a vague plan, but it needs building on the still-pending libxl cpuid work of Rogers. Both the toolstack and Xen need to learn about how to describe topology correctly (and I'm afraid this patch isn't correct even for a number of the simple cases), and know about "every VM booted up until this point in time" being wrong. ~Andrew