On Mon, Jul 31 2023 at 16:10, Michael Kelley wrote: > From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Sent: Monday, July 31, 2023 8:38 AM > The VM is an F72s_v2 in Azure running your patch set. The VM has > 72 vCPUs in two NUMA nodes across two physical Intel processors, with > 36 vCPUs in each NUMA node. > > The output is from /sys/kernel/debug/x86/topo/cpus, so the initial_apicid > is from CPUID, while the apicid is from read_apic_id() and matches the > MADT. As expected, the two values match for the first 36 vCPUs, but differ > by 28 (decimal) for the remaining 36. > > initial_apicid: 0 apicid: 0 ... > initial_apicid: 23 apicid: 23 > initial_apicid: 40 apicid: 24 ... > initial_apicid: 63 apicid: 47 Is there any indication in some other CPUID leaf which lets us deduce this wreckage? I don't think the hypervisor space (0x40000xx) has anything helpful, but staring at the architectural ones provided by hyper-V to the guest might give us an hint. Can you provide a cpuid dump for the boot CPU please? Thanks, tglx