Thank you everyone for your tests and your feedback!
The updates are live now: https://xcp-ng.org/blog/2025/12/18/december-2025-security-and-maintenance-updates-for-xcp-ng-8-3-lts/
@hitechhillbilly no it doesn't, it just ensures the N-th vCPU of Dom0 only runs on N-th pCPU of the machine.
Not sure about the practical impact of it, in the past it has been used for getting meaningful CPU temperatures from coretemp (with physical core matching virtual one), but it doesn't work anymore since Xen filters MSR accesses (including Dom0).
