On Fri, Oct 19, 2018 at 01:14:32PM +0200, Vitaly Kuznetsov wrote: > --- a/target/i386/kvm.c > +++ b/target/i386/kvm.c > @@ -798,6 +798,7 @@ int kvm_arch_init_vcpu(CPUState *cs) > uint32_t unused; > struct kvm_cpuid_entry2 *c; > uint32_t signature[3]; > + uint16_t evmcs_version; > int kvm_base = KVM_CPUID_SIGNATURE; > int r; > Error *local_err = NULL; > @@ -841,7 +842,7 @@ int kvm_arch_init_vcpu(CPUState *cs) > memset(signature, 0, 12); > memcpy(signature, cpu->hyperv_vendor_id, len); > } > - c->eax = HV_CPUID_MIN; > + c->eax = cpu->hyperv_evmcs ? HV_CPUID_MIN_NESTED : HV_CPUID_MIN;
I think these two aren't meant to be used on the hypervisor side. My understanding is that HV_CPUID_MIN is only there as a reminder that the real Hyper-V exposes at least that many hypervisor-specific leaves so the guest can rely on that. So I'd rather use directly HV_CPUID_IMPLEMENT_LIMITS : HV_CPUID_NESTED_FEATURES, and not introduce HV_CPUID_MIN_NESTED. Maybe better yet is to update this field with the maximum value while populating HV_* leaves: if (hyperv_enabled(cpu)) { uint32_t *cpuid_40000000_eax; c = &cpuid_data.entries[cpuid_i++]; c->function = HV_CPUID_VENDOR_AND_MAX_FUNCTIONS; cpuid_40000000_eax = &c->eax; *cpuid_40000000_eax = c->function; .... c = &cpuid_data.entries[cpuid_i++]; c->function = HV_CPUID_...; *cpuid_40000000_eax = max(*cpuid_40000000_eax, c->function); but I think it can be done later and doesn't need to hold this patch. Another question related to this: are the guests OK with leaves 0x40000006..0x40000009 missing? Thanks, Roman.