[PATCH 00/10] vfio: ccw: Refactoring the VFIO CCW state machine

Pierre Morel
2018-04-19T14:48:03Z

The goal of the patch serie is to enhance the state machine by
centralizing all state changes inside the state machine wrapper
and have a clear view of state changes.

Doing this will:
- facilitate the introduction of new events received from QEMU
(cancel/clear/stsh) or from the hardware (chr events).
- produce small, easy to maintain FSM functions with clear
incoming events and outgoing states

This series introduces new states and events and suppressed
others.
- VFIO_CCW_STATE_NOT_OPER : when the Sub-Channel is KO
- VFIO_CCW_STATE_STANDBY : when it is offline
- VFIO_CCW_STATE_IDLE : when it is ready for I/O
- VFIO_CCW_STATE_BUSY : when it is busy doing I/O
- VFIO_CCW_STATE_QUIESCING: when it is busy going offline

- VFIO_CCW_EVENT_INIT : the channel setup (admin)
- VFIO_CCW_EVENT_NOT_OPER : something really wrong happened
- VFIO_CCW_EVENT_SSCH_REQ : Starting an I/O request (UAPI)
- VFIO_CCW_EVENT_INTERRUPT: Receiving an interrupt (callback)
- VFIO_CCW_EVENT_SCH_EVENT: Receiving a channel event (callback)
- VFIO_CCW_EVENT_ONLINE : Channel is set online (admin)
- VFIO_CCW_EVENT_OFFLINE : Channel is set offline (admin)

The ABI did not change, so a standard QEMU devel branch can be used.

Pierre Morel (10):
vfio: ccw: Moving state change out of IRQ context
vfio: ccw: Transform FSM functions to return state
vfio: ccw: new SCH_EVENT event
vfio: ccw: replace IO_REQ event with SSCH_REQ event
vfio: ccw: Suppress unused event parameter
vfio: ccw: Make FSM functions atomic
vfio: ccw: Introduce the INIT event
vfio: ccw: Handling reset and shutdown with states
vfio: ccw: Suppressing the BOXED state
vfio: ccw: Let user wait when busy on IO

drivers/s390/cio/vfio_ccw_drv.c | 120 +++++++-------------
drivers/s390/cio/vfio_ccw_fsm.c | 215 +++++++++++++++++++++++++-----------
drivers/s390/cio/vfio_ccw_ops.c | 58 +++++-----
drivers/s390/cio/vfio_ccw_private.h | 21 +++-
4 files changed, 232 insertions(+), 182 deletions(-)

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2.7.4