KVM: arm64: Change the return type of kvm_vcpu_preferred_target()

kvm_vcpu_preferred_target() always return 0 because kvm_target_cpu()
never returns a negative error code.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211105011500.16280-1-yuehaibing@huawei.com

Author: YueHaibing

arch/arm64/include/asm/kvm_host.h

@@ -584,7 +584,7 @@ struct kvm_vcpu_stat {
 	u64 exits;
 };
 
-int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init);
+void kvm_vcpu_preferred_target(struct kvm_vcpu_init *init);
 unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu);
 int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices);
 int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);

arch/arm64/kvm/arm.c

@@ -1397,12 +1397,9 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		return kvm_vm_ioctl_set_device_addr(kvm, &dev_addr);
 	}
 	case KVM_ARM_PREFERRED_TARGET: {
-		int err;
 		struct kvm_vcpu_init init;
 
-		err = kvm_vcpu_preferred_target(&init);
-		if (err)
-			return err;
+		kvm_vcpu_preferred_target(&init);
 
 		if (copy_to_user(argp, &init, sizeof(init)))
 			return -EFAULT;

arch/arm64/kvm/guest.c

@@ -869,13 +869,10 @@ u32 __attribute_const__ kvm_target_cpu(void)
 	return KVM_ARM_TARGET_GENERIC_V8;
 }
 
-int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
+void kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
 {
 	u32 target = kvm_target_cpu();
 
-	if (target < 0)
-		return -ENODEV;
-
 	memset(init, 0, sizeof(*init));
 
 	/*
@@ -885,8 +882,6 @@ int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
 	 * target type.
 	 */
 	init->target = (__u32)target;
-
-	return 0;
 }
 
 int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)