Re: [Qemu-devel] [PATCH v2 14/23] hyperv: qom-ify SynIC

[Igor Mammedov]

On Thu, 29 Jun 2017 20:51:01 +0300
Roman Kagan <address@hidden> wrote:

> On Thu, Jun 29, 2017 at 05:05:46PM +0200, Igor Mammedov wrote:
> > On Wed, 21 Jun 2017 19:24:15 +0300
> > Roman Kagan <address@hidden> wrote:  
[...]
> 
> > > +    if (cpu->hyperv_synic) {
> > > +        if (kvm_vcpu_enable_cap(CPU(cpu), KVM_CAP_HYPERV_SYNIC, 0)) {
> > > +            fprintf(stderr, "failed to enable Hyper-V SynIC\n");
> > > +            return -ENOSYS;
> > > +        }
> > > +
> > > +        hyperv_synic_add(cpu);  
> > is synic KVM specific or may it work with TCG accel?  
> 
> No, it's exclusively KVM.  Actually most of it sits in the kernel.
> 
> > in either case, looks like hyperv_synic_add() should be called from
> > x86_cpu_realizefn(), the same like we do with APIC creating it
> > depending feature being enabled.  
> 
> I'm not sure I understand the reason, in view of it being exclusively
> KVM.
couldn't synic be emulated (if missing QEMU part is written) in TCG mode
or it relies on specific KVM features?

[...]