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