The goal of the patch serie is to secure the state machine by: - centralizing all state changes inside the state machine wrapper - make the state change atomic using mutexes - refactor the initialization to avoid using a subchannel without a guest This series introduces new states and events and suppressed others. Here the list of states and events used in this serie: - 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(N): 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_IO_REQ : Starting a SSCH request (UAPI) - VFIO_CCW_EVENT_INTERRUPT(N) : Receiving an interrupt (callback) - VFIO_CCW_EVENT_SCHIB_CHANGED(N): Receiving a channel event (callback) The user's ABI do not change. Pierre Morel (8): vfio: ccw: Moving state change out of IRQ context vfio: ccw: Transform FSM functions to return state vfio: ccw: new VFIO_CCW_EVENT_SCHIB_CHANGED event vfio: ccw: Only accept SSCH as an IO request vfio: ccw: Suppress unused event parameter vfio: ccw: Make FSM functions atomic vfio: ccw: Introduce the INIT event vfio: ccw: Suppressing the BOXED state drivers/s390/cio/vfio_ccw_drv.c | 71 ++++++----------- drivers/s390/cio/vfio_ccw_fsm.c | 147 +++++++++++++++++++++--------------- drivers/s390/cio/vfio_ccw_ops.c | 41 +++++----- drivers/s390/cio/vfio_ccw_private.h | 12 ++- 4 files changed, 137 insertions(+), 134 deletions(-) -- 2.7.4 Changelog: >From v2 to v3: - Concentrate more on securing the FSM: - abandonned ONLINE/OFFLINE events - abandonned make user wait on busy - abandonned switch case on command to keep old way of testing the START_SSCH bit in write syscall >From v1 to v2: - rebased on current Linux branch - change the name of VFIO_CCW_EVENT_SCH_EVENT to VFIO_CCW_EVENT_SCHIB_CHANGED - refactoring the initialization (mdev create/open and driver probe) - return -EAGAIN to let the low level retry the sending of events - make wait_for_completion interruptible
