Roman Kagan <rka...@virtuozzo.com> writes: > 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.
Makes sense, will do v2. > 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? They seem to be, however, after you've asked I'm leaning towards zeroing them 'just in case'. -- Vitaly