Re: [Qemu-devel] [Help] Windows2012 as Guest 64+cores on KVM Halts

[Gonglei (Arei)]

> 
> On 20/02/2017 10:19, Gonglei (Arei) wrote:
> > 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.
> 
> CPUID should never change with the same machine type and command line.
> 
OK, then how do we add compat code for the CPUID change? It's not a visible 
property.

Thanks,
-Gonglei

> Paolo
> 
> >> you should submit the patch for 2.9.
> >>
> >
> > Thanks,
> > -Gonglei
> >