From 6c69dfb67e84747cf071958594d939e845dfcc0c Mon Sep 17 00:00:00 2001 From: Gonglei Date: Mon, 11 Sep 2017 23:20:27 +0800 Subject: [PATCH] i386/cpu/hyperv: support over 64 vcpus for windows guests 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 Message-Id: <1505143227-14324-1-git-send-email-arei.gonglei@huawei.com> Signed-off-by: Paolo Bonzini --- include/hw/i386/pc.h | 5 +++++ target/i386/cpu.c | 14 ++++++++++++++ target/i386/cpu.h | 2 ++ target/i386/kvm.c | 3 ++- 4 files changed, 23 insertions(+), 1 deletion(-) diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index 8226904524..087d184ef5 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 7644f6dc2c..40c3091edf 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -4145,6 +4145,20 @@ 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), + + /* + * 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 that + * the hypervisor imposes no 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." + */ + 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 525d35d836..5c726f3e4b 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 739334a5a6..ee4e91fa64 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -786,7 +786,8 @@ int kvm_arch_init_vcpu(CPUState *cs) c = &cpuid_data.entries[cpuid_i++]; c->function = HYPERV_CPUID_IMPLEMENT_LIMITS; - c->eax = 0x40; + + c->eax = cpu->hv_max_vps; c->ebx = 0x40; kvm_base = KVM_CPUID_SIGNATURE_NEXT;