On Mon, Sep 11, 2017 at 11:20:27PM +0800, Gonglei wrote: > Starting with Windows Server 2012 and Windows 8, if > CPUID.40000005.EAX contains a value of -1, Windows assumes specific > limit to the number of VPs. In this case, Windows Server 2012 > guest VMs may use more than 64 VPs, up to the maximum supported > number of processors applicable to the specific Windows > version being used. > > https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs > > For compatibility, Let's introduce a new property for X86CPU, > named "x-hv-max-vps" as Eduardo's suggestion, and set it > to 0x40 before machine 2.10. > > (The "x-" prefix indicates that the property is not supposed to > be a stable user interface.) > > Signed-off-by: Gonglei <arei.gong...@huawei.com> > --- > include/hw/i386/pc.h | 5 +++++ > target/i386/cpu.c | 1 + > target/i386/cpu.h | 2 ++ > target/i386/kvm.c | 15 ++++++++++++++- > 4 files changed, 22 insertions(+), 1 deletion(-) > > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h > index 8226904..087d184 100644 > --- a/include/hw/i386/pc.h > +++ b/include/hw/i386/pc.h > @@ -371,6 +371,11 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t > *); > > #define PC_COMPAT_2_10 \ > HW_COMPAT_2_10 \ > + {\ > + .driver = TYPE_X86_CPU,\ > + .property = "x-hv-max-vps",\ > + .value = "0x40",\ > + }, > > #define PC_COMPAT_2_9 \ > HW_COMPAT_2_9 \ > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 69676e1..2702485 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -4145,6 +4145,7 @@ static Property x86_cpu_properties[] = { > false), > DEFINE_PROP_BOOL("vmware-cpuid-freq", X86CPU, vmware_cpuid_freq, true), > DEFINE_PROP_BOOL("tcg-cpuid", X86CPU, expose_tcg, true), > + DEFINE_PROP_INT32("x-hv-max-vps", X86CPU, hv_max_vps, -1), > DEFINE_PROP_END_OF_LIST() > }; > > diff --git a/target/i386/cpu.h b/target/i386/cpu.h > index 525d35d..5c726f3 100644 > --- a/target/i386/cpu.h > +++ b/target/i386/cpu.h > @@ -1282,6 +1282,8 @@ struct X86CPU { > int32_t socket_id; > int32_t core_id; > int32_t thread_id; > + > + int32_t hv_max_vps; > }; > > static inline X86CPU *x86_env_get_cpu(CPUX86State *env) > diff --git a/target/i386/kvm.c b/target/i386/kvm.c > index 6db7783..a898bef 100644 > --- a/target/i386/kvm.c > +++ b/target/i386/kvm.c > @@ -751,7 +751,20 @@ int kvm_arch_init_vcpu(CPUState *cs) > > c = &cpuid_data.entries[cpuid_i++]; > c->function = HYPERV_CPUID_IMPLEMENT_LIMITS; > - c->eax = 0x40; > + > + /* > + * From "Requirements for Implementing the Microsoft > + * Hypervisor Interface": > + * > https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs > + * > + * "Starting with Windows Server 2012 and Windows 8, if > + * CPUID.40000005.EAX contains a value of -1, Windows assumes > + * specific limit to the number of VPs. In this case, Windows > + * Server 2012 guest VMs may use more than 64 VPs, up to the > + * maximum supported number of processors applicable to the > + * specific Windows version being used." > + */
I would place this comment above the DEFINE_PROP_INT32 declaration, as its purpose is to explain the -1 default. > + c->eax = cpu->hv_max_vps; > c->ebx = 0x40; > > kvm_base = KVM_CPUID_SIGNATURE_NEXT; > -- > 1.8.3.1 > > -- Eduardo
