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The loadable component shall create its own contexts (if any) in its initialization routine,

just before confirming the creation of a new device instance. The loadable component

shall fill all required fields of the provided descriptor of the chapi_out communication

context with their respective values.

The loadable component can store the data path to both the chapi_in and the chapi_out

descriptors provided to the component by the CHARON core. However, the loadable

component is not allowed to modify any fields in the descriptor of the chapi_in

communication context that is provided to the component by CHARON.

Upon receiving a confirmation, the CHARON core completes the establishment of its own

context by filling the remaining fields of the descriptor of the chapi_in communication

context. When receiving a rejection from the initialization routine of the loadable

component, CHARON can terminate the establishment of its contexts.

This contexts binding process shall be considered done if, and only if:

• The whole configuration has been loaded, and

• The loadable component has confirmed the creation of a device instance.

2.5 Run-time communication

The run-time communication over the CHAPI communication channel is defined in terms

of operations or transactions. Each operation is either initiated by the CHARON core or by

the instance of the device provided by a loadable component. The side originating the

operation is called the initiator of the operation. Each operation must be processed by the

other side of the communication channel, which is called the target of the operation.

Both CHARON and a loadable component are / must be designed to work in a multi-

threaded environment. Therefore no assumptions shall be made regarding the thread in

which any particular operation is initiated. Nevertheless, certain operations put some

restrictions on the way in which both sides of the CHAPI communication are allowed to

initiate those operations.

Before the operation is initiated, the initiator shall prepare the operation context. When

prepared, the initiator calls the corresponding routine provided by the counterpart to

process the operation. Entry points to these routines are supplied in the corresponding

fields of the chapi_in and the chapi_out descriptors by both sides of the CHAPI

communication.

The CHAPI introduces the following types of operations:

• Access to the device IO addres space and memory address space. Such an operation

is only initiated by the CPU emulation thread. Therefore the target shall finish