[SeaBIOS] block device process_op question

[Daniel Castro]

Hello,

When the process_op is called and passed to the appropriate handling
function, how can I differentiate which drive the operation is
directed to? Inside my function xen_process_op called by process_op
with the drive_op as a parameter I use GET_GLOBAL(drive_s) to get the
block device, how can I be sure I am getting the correct drive, and
not another one?

If my question sounds confusing, maybe I am misunderstanding the use
of the structures... sorry about that... could someone help me with
this little bit.
Who calls process_op? who receives the answer from process_op?

Thanks for your time,

Daniel