KVM: Portability: move KVM_CHECK_EXTENSION

Make KVM_CHECK_EXTENSION code into a function, all archs can define its
capability independently.
Signed-off-by: Zhang Xiantao <xiantao.zhang@intel.com>
Acked-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/kvm.h

@@ -628,6 +628,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 			 unsigned int ioctl, unsigned long arg);
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu);
+
+int kvm_dev_ioctl_check_extension(long ext);
+
 int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
 				   struct
 				   kvm_userspace_memory_region *mem,

drivers/kvm/kvm_main.c

@@ -1198,23 +1198,9 @@ static long kvm_dev_ioctl(struct file *filp,
 			goto out;
 		r = kvm_dev_ioctl_create_vm();
 		break;
-	case KVM_CHECK_EXTENSION: {
-		int ext = (long)argp;
-
-		switch (ext) {
-		case KVM_CAP_IRQCHIP:
-		case KVM_CAP_HLT:
-		case KVM_CAP_MMU_SHADOW_CACHE_CONTROL:
-		case KVM_CAP_USER_MEMORY:
-		case KVM_CAP_SET_TSS_ADDR:
-			r = 1;
+	case KVM_CHECK_EXTENSION:
+		r = kvm_dev_ioctl_check_extension((long)argp);
 		break;
-		default:
-			r = 0;
-			break;
-		}
-		break;
-	}
 	case KVM_GET_VCPU_MMAP_SIZE:
 		r = -EINVAL;
 		if (arg)

drivers/kvm/x86.c

@@ -599,6 +599,26 @@ void decache_vcpus_on_cpu(int cpu)
 	spin_unlock(&kvm_lock);
 }
 
+int kvm_dev_ioctl_check_extension(long ext)
+{
+	int r;
+
+	switch (ext) {
+	case KVM_CAP_IRQCHIP:
+	case KVM_CAP_HLT:
+	case KVM_CAP_MMU_SHADOW_CACHE_CONTROL:
+	case KVM_CAP_USER_MEMORY:
+	case KVM_CAP_SET_TSS_ADDR:
+		r = 1;
+		break;
+	default:
+		r = 0;
+		break;
+	}
+	return r;
+
+}
+
 long kvm_arch_dev_ioctl(struct file *filp,
 			unsigned int ioctl, unsigned long arg)
 {