1. A computer program product for executing a machine instruction in a central processing unit, the computer program product comprising: a computer readable storage medium readable by a processing circuit and storing instruction for execution by the processing circuit for performing a method comprising: obtaining a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture, the machine instruction comprising: an opcode field identifying a modify adapter instruction; a first field identifying a location, the contents of which include a function handle identifying an adapter, a designation of an address space associated with the adapter to which a modify operation applies, and an operation control specifying the operation to be performed for the adapter, the operation control specifying one operation of a plurality of operations that can be selected; and a second field for identifying an address of a function information block to be used by the modify operation; and executing the machine instruction, the executing comprising: determining a value of the operation control; and modifying, responsive to the operation control, a table entry that includes parameters associated with the adapter, wherein the modifying comprises selectively updating one or more parameters of the table entry based on the operation control and based on one or more checks that depend on the operation control.