KVM: selftests: Multiplex return code and fd in __kvm_create_device()

Multiplex the return value and fd (on success) in __kvm_create_device()
to mimic common library helpers that return file descriptors, e.g. open().
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/aarch64/vgic_init.c

@@ -643,8 +643,8 @@ static void test_v3_its_region(void)
 int test_kvm_device(uint32_t gic_dev_type)
 {
 	struct vm_gic v;
-	int ret, fd;
 	uint32_t other;
+	int ret;
 
 	v.vm = vm_create_default_with_vcpus(NR_VCPUS, 0, 0, guest_code, NULL);
 
@@ -658,8 +658,8 @@ int test_kvm_device(uint32_t gic_dev_type)
 		return ret;
 	v.gic_fd = kvm_create_device(v.vm, gic_dev_type);
 
-	ret = __kvm_create_device(v.vm, gic_dev_type, &fd);
-	TEST_ASSERT(ret && errno == EEXIST, "create GIC device twice");
+	ret = __kvm_create_device(v.vm, gic_dev_type);
+	TEST_ASSERT(ret < 0 && errno == EEXIST, "create GIC device twice");
 
 	/* try to create the other gic_dev_type */
 	other = VGIC_DEV_IS_V2(gic_dev_type) ? KVM_DEV_TYPE_ARM_VGIC_V3

tools/testing/selftests/kvm/include/kvm_util_base.h

@@ -485,7 +485,7 @@ void vcpu_args_set(struct kvm_vm *vm, uint32_t vcpuid, unsigned int num, ...);
 int _kvm_device_check_attr(int dev_fd, uint32_t group, uint64_t attr);
 int kvm_device_check_attr(int dev_fd, uint32_t group, uint64_t attr);
 int __kvm_test_create_device(struct kvm_vm *vm, uint64_t type);
-int __kvm_create_device(struct kvm_vm *vm, uint64_t type, int *fd);
+int __kvm_create_device(struct kvm_vm *vm, uint64_t type);
 int kvm_create_device(struct kvm_vm *vm, uint64_t type);
 int _kvm_device_access(int dev_fd, uint32_t group, uint64_t attr,
 		       void *val, bool write);

tools/testing/selftests/kvm/lib/aarch64/vgic.c

@@ -51,8 +51,9 @@ int vgic_v3_setup(struct kvm_vm *vm, unsigned int nr_vcpus, uint32_t nr_irqs,
 			nr_vcpus, nr_vcpus_created);
 
 	/* Distributor setup */
-	if (__kvm_create_device(vm, KVM_DEV_TYPE_ARM_VGIC_V3, &gic_fd))
-		return -1;
+	gic_fd = __kvm_create_device(vm, KVM_DEV_TYPE_ARM_VGIC_V3);
+	if (gic_fd < 0)
+		return gic_fd;
 
 	kvm_device_access(gic_fd, KVM_DEV_ARM_VGIC_GRP_NR_IRQS,
 			0, &nr_irqs, true);

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -1639,27 +1639,25 @@ int __kvm_test_create_device(struct kvm_vm *vm, uint64_t type)
 	return __vm_ioctl(vm, KVM_CREATE_DEVICE, &create_dev);
 }
 
-int __kvm_create_device(struct kvm_vm *vm, uint64_t type, int *fd)
+int __kvm_create_device(struct kvm_vm *vm, uint64_t type)
 {
 	struct kvm_create_device create_dev = {
 		.type = type,
 		.fd = -1,
 		.flags = 0,
 	};
-	int ret;
+	int err;
 
-	ret = __vm_ioctl(vm, KVM_CREATE_DEVICE, &create_dev);
-	*fd = create_dev.fd;
-	return ret;
+	err = __vm_ioctl(vm, KVM_CREATE_DEVICE, &create_dev);
+	TEST_ASSERT(err <= 0, "KVM_CREATE_DEVICE shouldn't return a positive value");
+	return err ? : create_dev.fd;
 }
 
 int kvm_create_device(struct kvm_vm *vm, uint64_t type)
 {
-	int fd, ret;
-
-	ret = __kvm_create_device(vm, type, &fd);
+	int fd = __kvm_create_device(vm, type);
 
-	TEST_ASSERT(!ret, "KVM_CREATE_DEVICE IOCTL failed, rc: %i errno: %i", ret, errno);
+	TEST_ASSERT(fd >= 0, "KVM_CREATE_DEVICE IOCTL failed, rc: %i errno: %i", fd, errno);
 	return fd;
 }