Hi Paolo, > > > On 16/02/2017 02:31, Gonglei (Arei) wrote: > > And the below patch works for me, I can support max 255 vcpus for WS2012 > > with hyper-v enlightenments. > > > > diff --git a/target/i386/kvm.c b/target/i386/kvm.c > > index 27fd050..efe3cbc 100644 > > --- a/target/i386/kvm.c > > +++ b/target/i386/kvm.c > > @@ -772,7 +772,7 @@ int kvm_arch_init_vcpu(CPUState *cs) > > > > c = &cpuid_data.entries[cpuid_i++]; > > c->function = HYPERV_CPUID_IMPLEMENT_LIMITS; > > - c->eax = 0x40; > > + c->eax = -1; > > c->ebx = 0x40; > > > > kvm_base = KVM_CPUID_SIGNATURE_NEXT; > > This needs to depend on the machine type, but apart from that I think I don't know why. Because the negative effects for this change don't exist on current QEMU IIUC, and we don't have compatible problems for live migration. > you should submit the patch for 2.9. > Thanks, -Gonglei
