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

Pierre Morel
2018-05-03T10:31:41Z

On 30/04/2018 17:39, Cornelia Huck wrote:
> 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?
>
It is the only way to go out of the NOT_OPER state.

The idea is to introduce recoverycode in a later version.

However, no problem to suppress this state until we get there so I will
remove it in V2.

--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany