3 files changed, 143 insertions, 0 deletions

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index a9b5d6c4e3eb..e3c076020d4e 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1752,3 +1752,124 @@ int kvm_vm_ioctl_hv_eventfd(struct kvm *kvm, struct kvm_hyperv_eventfd *args)
 		return kvm_hv_eventfd_deassign(kvm, args->conn_id);
 	return kvm_hv_eventfd_assign(kvm, args->conn_id, args->fd);
 }
+
+int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
+				struct kvm_cpuid_entry2 __user *entries)
+{
+	uint16_t evmcs_ver = kvm_x86_ops->nested_get_evmcs_version(vcpu);
+	struct kvm_cpuid_entry2 cpuid_entries[] = {
+		{ .function = HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS },
+		{ .function = HYPERV_CPUID_INTERFACE },
+		{ .function = HYPERV_CPUID_VERSION },
+		{ .function = HYPERV_CPUID_FEATURES },
+		{ .function = HYPERV_CPUID_ENLIGHTMENT_INFO },
+		{ .function = HYPERV_CPUID_IMPLEMENT_LIMITS },
+		{ .function = HYPERV_CPUID_NESTED_FEATURES },
+	};
+	int i, nent = ARRAY_SIZE(cpuid_entries);
+
+	/* Skip NESTED_FEATURES if eVMCS is not supported */
+	if (!evmcs_ver)
+		--nent;
+
+	if (cpuid->nent < nent)
+		return -E2BIG;
+
+	if (cpuid->nent > nent)
+		cpuid->nent = nent;
+
+	for (i = 0; i < nent; i++) {
+		struct kvm_cpuid_entry2 *ent = &cpuid_entries[i];
+		u32 signature[3];
+
+		switch (ent->function) {
+		case HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS:
+			memcpy(signature, "Linux KVM Hv", 12);
+
+			ent->eax = HYPERV_CPUID_NESTED_FEATURES;
+			ent->ebx = signature[0];
+			ent->ecx = signature[1];
+			ent->edx = signature[2];
+			break;
+
+		case HYPERV_CPUID_INTERFACE:
+			memcpy(signature, "Hv#1\0\0\0\0\0\0\0\0", 12);
+			ent->eax = signature[0];
+			break;
+
+		case HYPERV_CPUID_VERSION:
+			/*
+			 * We implement some Hyper-V 2016 functions so let's use
+			 * this version.
+			 */
+			ent->eax = 0x00003839;
+			ent->ebx = 0x000A0000;
+			break;
+
+		case HYPERV_CPUID_FEATURES:
+			ent->eax |= HV_X64_MSR_VP_RUNTIME_AVAILABLE;
+			ent->eax |= HV_MSR_TIME_REF_COUNT_AVAILABLE;
+			ent->eax |= HV_X64_MSR_SYNIC_AVAILABLE;
+			ent->eax |= HV_MSR_SYNTIMER_AVAILABLE;
+			ent->eax |= HV_X64_MSR_APIC_ACCESS_AVAILABLE;
+			ent->eax |= HV_X64_MSR_HYPERCALL_AVAILABLE;
+			ent->eax |= HV_X64_MSR_VP_INDEX_AVAILABLE;
+			ent->eax |= HV_X64_MSR_RESET_AVAILABLE;
+			ent->eax |= HV_MSR_REFERENCE_TSC_AVAILABLE;
+			ent->eax |= HV_X64_MSR_GUEST_IDLE_AVAILABLE;
+			ent->eax |= HV_X64_ACCESS_FREQUENCY_MSRS;
+			ent->eax |= HV_X64_ACCESS_REENLIGHTENMENT;
+
+			ent->ebx |= HV_X64_POST_MESSAGES;
+			ent->ebx |= HV_X64_SIGNAL_EVENTS;
+
+			ent->edx |= HV_FEATURE_FREQUENCY_MSRS_AVAILABLE;
+			ent->edx |= HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;
+			ent->edx |= HV_STIMER_DIRECT_MODE_AVAILABLE;
+
+			break;
+
+		case HYPERV_CPUID_ENLIGHTMENT_INFO:
+			ent->eax |= HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED;
+			ent->eax |= HV_X64_APIC_ACCESS_RECOMMENDED;
+			ent->eax |= HV_X64_SYSTEM_RESET_RECOMMENDED;
+			ent->eax |= HV_X64_RELAXED_TIMING_RECOMMENDED;
+			ent->eax |= HV_X64_CLUSTER_IPI_RECOMMENDED;
+			ent->eax |= HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED;
+			ent->eax |= HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
+
+			/*
+			 * Default number of spinlock retry attempts, matches
+			 * HyperV 2016.
+			 */
+			ent->ebx = 0x00000FFF;
+
+			break;
+
+		case HYPERV_CPUID_IMPLEMENT_LIMITS:
+			/* Maximum number of virtual processors */
+			ent->eax = KVM_MAX_VCPUS;
+			/*
+			 * Maximum number of logical processors, matches
+			 * HyperV 2016.
+			 */
+			ent->ebx = 64;
+
+			break;
+
+		case HYPERV_CPUID_NESTED_FEATURES:
+			ent->eax = evmcs_ver;
+
+			break;
+
+		default:
+			break;
+		}
+	}
+
+	if (copy_to_user(entries, cpuid_entries,
+			 nent * sizeof(struct kvm_cpuid_entry2)))
+		return -EFAULT;
+
+	return 0;
+}
diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index 9c21c3479899..fd7cf13a2144 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h
@@ -97,5 +97,7 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm,
 void kvm_hv_init_vm(struct kvm *kvm);
 void kvm_hv_destroy_vm(struct kvm *kvm);
 int kvm_vm_ioctl_hv_eventfd(struct kvm *kvm, struct kvm_hyperv_eventfd *args);
+int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
+				struct kvm_cpuid_entry2 __user *entries);
 
 #endif
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 54ef79421c6b..18b7817af2bc 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2997,6 +2997,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_HYPERV_TLBFLUSH:
 	case KVM_CAP_HYPERV_SEND_IPI:
 	case KVM_CAP_HYPERV_ENLIGHTENED_VMCS:
+	case KVM_CAP_HYPERV_CPUID:
 	case KVM_CAP_PCI_SEGMENT:
 	case KVM_CAP_DEBUGREGS:
 	case KVM_CAP_X86_ROBUST_SINGLESTEP:
@@ -4191,6 +4192,25 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		r = kvm_x86_ops->set_nested_state(vcpu, user_kvm_nested_state, &kvm_state);
 		break;
 	}
+	case KVM_GET_SUPPORTED_HV_CPUID: {
+		struct kvm_cpuid2 __user *cpuid_arg = argp;
+		struct kvm_cpuid2 cpuid;
+
+		r = -EFAULT;
+		if (copy_from_user(&cpuid, cpuid_arg, sizeof(cpuid)))
+			goto out;
+
+		r = kvm_vcpu_ioctl_get_hv_cpuid(vcpu, &cpuid,
+						cpuid_arg->entries);
+		if (r)
+			goto out;
+
+		r = -EFAULT;
+		if (copy_to_user(cpuid_arg, &cpuid, sizeof(cpuid)))
+			goto out;
+		r = 0;
+		break;
+	}
 	default:
 		r = -EINVAL;
 	}