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>> >> - tscan->c->topo.initial_apicid = leaf.ext_apic_id; >> + /* >> + * Prefer initial_apicid parsed from CPUID leaf 0x8000026 or 0xb >> + * if available. Otherwise prefer the one from leaf 0x8000001e >> + * over 0x1. >> + */ >> + if (!has_topoext) >> + tscan->c->topo.initial_apicid = leaf.ext_apic_id; > > My understanding is that the rest of this function continues to work > properly with an all-zero return value from CPUID leaf 0x8000001e - data > from topoext is preferred where available, and other sources are used > for llc_id. Yes. QEMU just errs on the side of caution for CoreID collision in 0x8000001e and "NumSharingCache" in 0x8000001d EAX[25:14] can still represent 2^12 (4096) CPUs in each cache domain which is larger than the total number of vCPUs possible currently I believe. > And, this fixes the firmware bug warning seen during a guest boot in > qemu for me, so for this patch: > Tested-by: Naveen N Rao (AMD) Thank you for debugging the issue and testing :) -- Thanks and Regards, Prateek