Re: [PATCH v3 08/11] vfio/ccw: Create an OPEN FSM Event

Matthew Rosato
2022-07-05T19:29:24Z

On 6/30/22 4:36 PM, Eric Farman wrote:
> Move the process of enabling a subchannel for use by vfio-ccw
> into the FSM, such that it can manage the sequence of lifecycle
> events for the device.
>
> That is, if the FSM state is NOT_OPER(erational), then do the work
> that would enable the subchannel and move the FSM to STANDBY state.
> An attempt to perform this event again from any of the other operating
> states (IDLE, CP_PROCESSING, CP_PENDING) will convert the device back
> to NOT_OPER so the configuration process can be started again.
>
> Signed-off-by: Eric Farman <farman@linux.ibm.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>

> ---
> drivers/s390/cio/vfio_ccw_drv.c | 9 ++-------
> drivers/s390/cio/vfio_ccw_fsm.c | 21 +++++++++++++++++++++
> drivers/s390/cio/vfio_ccw_private.h | 1 +
> 3 files changed, 24 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
> index fe87a2652a22..7d9189640da3 100644
> --- a/drivers/s390/cio/vfio_ccw_drv.c
> +++ b/drivers/s390/cio/vfio_ccw_drv.c
> @@ -231,15 +231,10 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
>
> dev_set_drvdata(&sch->dev, private);
>
> - spin_lock_irq(sch->lock);
> - sch->isc = VFIO_CCW_ISC;
> - ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
> - spin_unlock_irq(sch->lock);
> - if (ret)
> + vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_OPEN);
> + if (private->state == VFIO_CCW_STATE_NOT_OPER)
> goto out_free;
>
> - private->state = VFIO_CCW_STATE_STANDBY;
> -
> ret = mdev_register_device(&sch->dev, &vfio_ccw_mdev_driver);
> if (ret)
> goto out_disable;
> diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
> index 88e529a2e184..2811b2040490 100644
> --- a/drivers/s390/cio/vfio_ccw_fsm.c
> +++ b/drivers/s390/cio/vfio_ccw_fsm.c
> @@ -11,6 +11,8 @@
>
> #include <linux/vfio.h>
>
> +#include <asm/isc.h>
> +
> #include "ioasm.h"
> #include "vfio_ccw_private.h"
>
> @@ -368,6 +370,20 @@ static void fsm_irq(struct vfio_ccw_private *private,
> complete(private->completion);
> }
>
> +static void fsm_open(struct vfio_ccw_private *private,
> + enum vfio_ccw_event event)
> +{
> + struct subchannel *sch = private->sch;
> + int ret;
> +
> + spin_lock_irq(sch->lock);
> + sch->isc = VFIO_CCW_ISC;
> + ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
> + if (!ret)
> + private->state = VFIO_CCW_STATE_STANDBY;
> + spin_unlock_irq(sch->lock);
> +}
> +
> /*
> * Device statemachine
> */
> @@ -377,29 +393,34 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
> [VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
> [VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_error,
> [VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
> + [VFIO_CCW_EVENT_OPEN] = fsm_open,
> },
> [VFIO_CCW_STATE_STANDBY] = {
> [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
> [VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
> [VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_error,
> [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
> + [VFIO_CCW_EVENT_OPEN] = fsm_notoper,
> },
> [VFIO_CCW_STATE_IDLE] = {
> [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
> [VFIO_CCW_EVENT_IO_REQ] = fsm_io_request,
> [VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_request,
> [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
> + [VFIO_CCW_EVENT_OPEN] = fsm_notoper,
> },
> [VFIO_CCW_STATE_CP_PROCESSING] = {
> [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
> [VFIO_CCW_EVENT_IO_REQ] = fsm_io_retry,
> [VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_retry,
> [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
> + [VFIO_CCW_EVENT_OPEN] = fsm_notoper,
> },
> [VFIO_CCW_STATE_CP_PENDING] = {
> [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
> [VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
> [VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_request,
> [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
> + [VFIO_CCW_EVENT_OPEN] = fsm_notoper,
> },
> };
> diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
> index 4cfdd5fc0961..8dff1699a7d9 100644
> --- a/drivers/s390/cio/vfio_ccw_private.h
> +++ b/drivers/s390/cio/vfio_ccw_private.h
> @@ -142,6 +142,7 @@ enum vfio_ccw_event {
> VFIO_CCW_EVENT_IO_REQ,
> VFIO_CCW_EVENT_INTERRUPT,
> VFIO_CCW_EVENT_ASYNC_REQ,
> + VFIO_CCW_EVENT_OPEN,
> /* last element! */
> NR_VFIO_CCW_EVENTS
> };