> > On 12/09/2017 03:41, Gonglei (Arei) wrote: > > > >> -----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? > > Done, also changing the sentence to "Windows assumes that the hypervisor > imposes no specific limit to the number of VPs" as in the Microsoft > document. > > Paolo > Nice, thanks!
Regards, -Gonglei
