kvm: arm64: add KVM_CAP_ARM_CPU_FEATURE extension

hulk inclusion
category: feature
bugzilla: 48052
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: NZhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm64/kvm/arm.c

@@ -198,6 +198,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_ARM_IRQ_LINE_LAYOUT_2:
 	case KVM_CAP_ARM_NISV_TO_USER:
 	case KVM_CAP_ARM_INJECT_EXT_DABT:
+	case KVM_CAP_ARM_CPU_FEATURE:
 		r = 1;
 		break;
 	case KVM_CAP_ARM_SET_DEVICE_ADDR:

include/uapi/linux/kvm.h

@@ -1062,6 +1062,8 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_X86_MSR_FILTER 189
 #define KVM_CAP_ENFORCE_PV_FEATURE_CPUID 190
 
+#define KVM_CAP_ARM_CPU_FEATURE 555
+
 #ifdef KVM_CAP_IRQ_ROUTING
 
 struct kvm_irq_routing_irqchip {