Re: [PATCH 07/10] vfio: ccw: Introduce the INIT event

Cornelia Huck
2018-04-30T15:39:10Z

On Thu, 19 Apr 2018 16:48:10 +0200
Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:

> The VFIO_CCW_EVENT_INIT event allows to export the initial state
> into the FSM.

I don't know, that feels a bit unintuitive to me. I would naively
expect initialization to be done _before_ we activate processing via
the state machine.

>
> Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
> ---
> drivers/s390/cio/vfio_ccw_drv.c | 26 +++++++++++---------------
> drivers/s390/cio/vfio_ccw_fsm.c | 21 +++++++++++++++++++++
> drivers/s390/cio/vfio_ccw_ops.c | 11 -----------
> drivers/s390/cio/vfio_ccw_private.h | 1 +
> 4 files changed, 33 insertions(+), 26 deletions(-)

> /*
> * Device statemachine
> */
> fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
> [VFIO_CCW_STATE_NOT_OPER] = {
> + [VFIO_CCW_EVENT_INIT] = fsm_init,
> [VFIO_CCW_EVENT_NOT_OPER] = fsm_nop,
> [VFIO_CCW_EVENT_SSCH_REQ] = fsm_io_error,
> [VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
> [VFIO_CCW_EVENT_SCH_EVENT] = fsm_nop,
> },
> [VFIO_CCW_STATE_STANDBY] = {
> + [VFIO_CCW_EVENT_INIT] = fsm_nop,
> [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
> [VFIO_CCW_EVENT_SSCH_REQ] = fsm_io_error,
> [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
> [VFIO_CCW_EVENT_SCH_EVENT] = fsm_sch_event,
> },
> [VFIO_CCW_STATE_IDLE] = {
> + [VFIO_CCW_EVENT_INIT] = fsm_nop,
> [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
> [VFIO_CCW_EVENT_SSCH_REQ] = fsm_io_request,
> [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
> [VFIO_CCW_EVENT_SCH_EVENT] = fsm_sch_event,
> },
> [VFIO_CCW_STATE_BOXED] = {
> + [VFIO_CCW_EVENT_INIT] = fsm_nop,
> [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
> [VFIO_CCW_EVENT_SSCH_REQ] = fsm_io_busy,
> [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
> [VFIO_CCW_EVENT_SCH_EVENT] = fsm_sch_event,
> },
> [VFIO_CCW_STATE_BUSY] = {
> + [VFIO_CCW_EVENT_INIT] = fsm_nop,
> [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
> [VFIO_CCW_EVENT_SSCH_REQ] = fsm_io_busy,
> [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,

...especially as you only call it if in the NOT_OPER state. Why should
this event be generated in any case but in the very beginning?