Re: [Qemu-devel] [PATCH v2 1/1] cpu: report hyperv feature words through qom

[Eduardo Habkost]

On Tue, Jun 21, 2016 at 02:00:22PM +0200, Paolo Bonzini wrote:
> On 20/06/2016 17:29, Denis V. Lunev wrote:
> > +static int hyperv_handle_properties(CPUState *cs)
> > +{
> > +    X86CPU *cpu = X86_CPU(cs);
> > +    CPUX86State *env = &cpu->env;
> > +
> > +    if (cpu->hyperv_relaxed_timing) {
> > +        env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_HYPERCALL_AVAILABLE;
> > +    }
> > +    if (cpu->hyperv_vapic) {
> > +        env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_HYPERCALL_AVAILABLE;
> > +        env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_APIC_ACCESS_AVAILABLE;
> > +        has_msr_hv_vapic = true;
> > +    }
> > +    if (cpu->hyperv_time &&
> > +            kvm_check_extension(cs->kvm_state, KVM_CAP_HYPERV_TIME) > 0) {
> > +        env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_HYPERCALL_AVAILABLE;
> > +        env->features[FEAT_HYPERV_EAX] |= 
> > HV_X64_MSR_TIME_REF_COUNT_AVAILABLE;
> > +        env->features[FEAT_HYPERV_EAX] |= 0x200;
> > +        has_msr_hv_tsc = true;
> > +    }
> > +    if (cpu->hyperv_crash && has_msr_hv_crash) {
> > +        env->features[FEAT_HYPERV_EDX] |= HV_X64_GUEST_CRASH_MSR_AVAILABLE;
> > +    }
> > +    if (cpu->hyperv_reset && has_msr_hv_reset) {
> > +        env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_RESET_AVAILABLE;
> > +    }
> > +    if (cpu->hyperv_vpindex && has_msr_hv_vpindex) {
> > +        env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_VP_INDEX_AVAILABLE;
> > +    }
> > +    if (cpu->hyperv_runtime && has_msr_hv_runtime) {
> > +        env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_VP_RUNTIME_AVAILABLE;
> 
> Yay, thanks for this!
> 
> I'm curious if there's anything more you need to support "-cpu
> ...,hv_time,enforce", and have it fail if KVM_CAP_HYPERV_TIME is not
> available.

To do that, we need to:
1) Replace the cpu->hyperv_XXX boolean with (env->features[...] & HV_XXX)
2) Move the "hv-XXX" property from x86_cpu_properties to the
   corresponding feature_name array
3) Report the features in kvm_arch_get_supported_cpuid(), with
   the corresponding kvm_check_extension() or has_msr_XXX checks.

-- 
Eduardo