kvm: arm64: add KVM_CAP_ARM_CPU_FEATURE extension

hulk inclusion
category: feature
bugzilla: NA
CVE: NA

Add KVM_CAP_ARM_CPU_FEATURE extension for userpace to check whether KVM
supports to set CPU features in AArch64.
Signed-off-by: Nzhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: NPeng Liang <liangpeng10@huawei.com>
Reviewed-by: NXiangyou Xie <xiexiangyou@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

include/uapi/linux/kvm.h

@@ -967,6 +967,8 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_ARM_VM_IPA_SIZE 165 /* returns maximum IPA bits for a VM */
 #define KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 174
 
+#define KVM_CAP_ARM_CPU_FEATURE 555
+
 #ifdef KVM_CAP_IRQ_ROUTING
 
 struct kvm_irq_routing_irqchip {

virt/kvm/arm/arm.c

@@ -218,6 +218,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_MP_STATE:
 	case KVM_CAP_IMMEDIATE_EXIT:
 	case KVM_CAP_ARM_IRQ_LINE_LAYOUT_2:
+	case KVM_CAP_ARM_CPU_FEATURE:
 		r = 1;
 		break;
 	case KVM_CAP_ARM_SET_DEVICE_ADDR: