> -----Original Message----- > From: Eduardo Habkost [mailto:ehabk...@redhat.com] > Sent: Tuesday, September 12, 2017 2:38 AM > To: Gonglei (Arei) > Cc: qemu-devel@nongnu.org; m...@redhat.com; pbonz...@redhat.com; > r...@twiddle.net; mtosa...@redhat.com; vroze...@redhat.com; > Huangweidong (C) > Subject: Re: [PATCH] i386/cpu/hyperv: support over 64 vcpus for windows > guests > > 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/referenc > e/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/referenc > e/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. > Fine, do I need to send v2? Or you adjust it directly?
Thanks, -Gonglei > > > + c->eax = cpu->hv_max_vps; > > c->ebx = 0x40; > > > > kvm_base = KVM_CPUID_SIGNATURE_NEXT; > > -- > > 1.8.3.1 > > > > > > -- > Eduardo
