I found some example in odroid_vm, I want to make sure my understanding is correct? In CMakeLists.txt DeclareCAmkESComponent(HelloWorld) is just tell me there is a component called “HelloWorld” If you want this component to be compiled to project You must add call in your assembly in .cmakes file like below:

Correct.  Camkes builds a different binary for each component instance.  DeclareCAmkESComponent(HelloWorld) declares a component type HelloWorld, but because each instance of a HelloWorld component could have different connections or configuration there is a separate binary built for each one.  Therefore if a component instance doesn't exist for a component type then nothing for that component will be built.

                 assembly {                           composition {                         component HelloWorld hello;

                          }                                                                                             Thank you very much   hi， I have some question about the compile of global-components in camkes_arm_vm project. 1、In projects/global-components/components, there are some directory include FileServer, SerialServer, TimeServer and the others.     I found FileServer had been compiled to project， but the other directory have not been compiled     Is there some on-off switch control the compile ？ But I did not find it. 2、The CAmkES of FileServer component did not have a "int run(void) {},

      If I want to add an new component with run entry， but it is not rootserver（I think one project only have one rootserver），it run with vm rootserver parallelly？      what should I do ？ Is there some example.                                                                                             Thank you very much

Try looking at the sample serialserver camkes app (https://github.com/seL4/camkes/blob/master/apps/serialserver/serialserver.ca...) for a project that uses the SertialServer and TimeServer components.  Alternatively the vm_serial_server app (https://github.com/SEL4PROJ/camkes-arm-vm/blob/master/apps/vm_serial_server/...) in the camkes_arm_vm project uses all of the components you listed.