Add the hypercall sub-ops and the structures for the shared data used
in the FIFO-based event channel ABI.
The design document for this new ABI is available here:
http://xenbits.xen.org/people/dvrabel/event-channels-H.pdf
In summary, events are reported using a per-domain shared event array
of event words. Each event word has PENDING, LINKED and MASKED bits
and a LINK field for pointing to the next event in the event queue.
There are 16 event queues (with different priorities) per-VCPU.
Key advantages of this new ABI include:
- Support for over 100,000 events (2^17).
- 16 different event priorities.
- Improved fairness in event latency through the use of FIFOs.
The ABI is available in Xen 4.4 and later.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Refactor static array evtchn_to_irq array to be dynamically allocated by
implementing get and set functions for accesses to the array.
Two new port ops are added: max_channels (maximum supported number of
event channels) and nr_channels (number of currently usable event
channels). For the 2-level ABI, these numbers are both the same as
the shared data structure is a fixed size. For the FIFO ABI, these
will be different as the event array is expanded dynamically.
This allows more than 65000 event channels so an unsigned short is no
longer sufficient for an event channel port number and unsigned int is
used instead.
Signed-off-by: Malcolm Crossley <malcolm.crossley@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
evtchn_ops contains the low-level operations that access the shared
data structures. This allows alternate ABIs to be supported.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
In preparation for alternative event channel ABIs, move all the
functions accessing the shared data structures into their own file.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
