selftests: KVM: Fix kvm device helper ioctl assertions

The KVM_CREATE_DEVICE and KVM_{GET,SET}_DEVICE_ATTR ioctls are defined
to return a value of zero on success. As such, tighten the assertions in
the helper functions to only pass if the return code is zero.
Suggested-by: NAndrew Jones <drjones@redhat.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NOliver Upton <oupton@google.com>
Message-Id: <20210916181555.973085-4-oupton@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

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

@@ -1984,7 +1984,7 @@ int kvm_device_check_attr(int dev_fd, uint32_t group, uint64_t attr)
 {
 	int ret = _kvm_device_check_attr(dev_fd, group, attr);
 
-	TEST_ASSERT(ret >= 0, "KVM_HAS_DEVICE_ATTR failed, rc: %i errno: %i", ret, errno);
+	TEST_ASSERT(!ret, "KVM_HAS_DEVICE_ATTR failed, rc: %i errno: %i", ret, errno);
 	return ret;
 }
 
@@ -2008,7 +2008,7 @@ int kvm_create_device(struct kvm_vm *vm, uint64_t type, bool test)
 	ret = _kvm_create_device(vm, type, test, &fd);
 
 	if (!test) {
-		TEST_ASSERT(ret >= 0,
+		TEST_ASSERT(!ret,
 			    "KVM_CREATE_DEVICE IOCTL failed, rc: %i errno: %i", ret, errno);
 		return fd;
 	}
@@ -2036,7 +2036,7 @@ int kvm_device_access(int dev_fd, uint32_t group, uint64_t attr,
 {
 	int ret = _kvm_device_access(dev_fd, group, attr, val, write);
 
-	TEST_ASSERT(ret >= 0, "KVM_SET|GET_DEVICE_ATTR IOCTL failed, rc: %i errno: %i", ret, errno);
+	TEST_ASSERT(!ret, "KVM_SET|GET_DEVICE_ATTR IOCTL failed, rc: %i errno: %i", ret, errno);
 	return ret;
 }