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vfio/ccw: Create a CLOSE FSM event

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Refactor the vfio_ccw_sch_quiesce() routine to extract the bit that
disables the subchannel and affects the FSM state. Use this to form
the basis of a CLOSE event that will mirror the OPEN event, and move
the subchannel back to NOT_OPER state.

A key difference with that mirroring is that while OPEN handles the
transition from NOT_OPER => STANDBY, the later probing of the mdev
handles the transition from STANDBY => IDLE. On the other hand,
the CLOSE event will move from one of the operating states {IDLE,
CP_PROCESSING, CP_PENDING} => NOT_OPER. That is, there is no stop
in a STANDBY state on the deconfigure path.

Add a call to cp_free() in this event, such that it is captured for
the various permutations of this event.

In the unlikely event that cio_disable_subchannel() returns -EBUSY,
the remaining logic of vfio_ccw_sch_quiesce() can still be used.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20220707135737.720765-10-farman@linux.ibm.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Eric Farman 2022-07-07 15:57:35 +02:00 committed by Alex Williamson
parent 62ec0d49e6
commit f4b4ed4477
4 changed files with 34 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/s390/cio/vfio_ccw_drv.c
View File

@ -41,13 +41,6 @@ int vfio_ccw_sch_quiesce(struct subchannel *sch)
DECLARE_COMPLETION_ONSTACK(completion);
int iretry, ret = 0;
spin_lock_irq(sch->lock);
if (!sch->schib.pmcw.ena)
goto out_unlock;
ret = cio_disable_subchannel(sch);
if (ret != -EBUSY)
goto out_unlock;
iretry = 255;
do {
@ -74,9 +67,7 @@ int vfio_ccw_sch_quiesce(struct subchannel *sch)
spin_lock_irq(sch->lock);
ret = cio_disable_subchannel(sch);
} while (ret == -EBUSY);
out_unlock:
private->state = VFIO_CCW_STATE_NOT_OPER;
spin_unlock_irq(sch->lock);
return ret;
}
@ -256,7 +247,7 @@ static void vfio_ccw_sch_remove(struct subchannel *sch)
{
struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
vfio_ccw_sch_quiesce(sch);
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
mdev_unregister_device(&sch->dev);
dev_set_drvdata(&sch->dev, NULL);
@ -270,7 +261,9 @@ static void vfio_ccw_sch_remove(struct subchannel *sch)
static void vfio_ccw_sch_shutdown(struct subchannel *sch)
{
vfio_ccw_sch_quiesce(sch);
struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
}
/**

26
drivers/s390/cio/vfio_ccw_fsm.c
View File

@ -384,6 +384,27 @@ static void fsm_open(struct vfio_ccw_private *private,
spin_unlock_irq(sch->lock);
}
static void fsm_close(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
struct subchannel *sch = private->sch;
int ret;
spin_lock_irq(sch->lock);
if (!sch->schib.pmcw.ena)
goto out_unlock;
ret = cio_disable_subchannel(sch);
if (ret == -EBUSY)
vfio_ccw_sch_quiesce(sch);
out_unlock:
private->state = VFIO_CCW_STATE_NOT_OPER;
spin_unlock_irq(sch->lock);
cp_free(&private->cp);
}
/*
* Device statemachine
*/
@ -394,6 +415,7 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_error,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
[VFIO_CCW_EVENT_OPEN] = fsm_open,
[VFIO_CCW_EVENT_CLOSE] = fsm_nop,
},
[VFIO_CCW_STATE_STANDBY] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
@ -401,6 +423,7 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_error,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
[VFIO_CCW_EVENT_OPEN] = fsm_notoper,
[VFIO_CCW_EVENT_CLOSE] = fsm_close,
},
[VFIO_CCW_STATE_IDLE] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
@ -408,6 +431,7 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_request,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
[VFIO_CCW_EVENT_OPEN] = fsm_notoper,
[VFIO_CCW_EVENT_CLOSE] = fsm_close,
},
[VFIO_CCW_STATE_CP_PROCESSING] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
@ -415,6 +439,7 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_retry,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
[VFIO_CCW_EVENT_OPEN] = fsm_notoper,
[VFIO_CCW_EVENT_CLOSE] = fsm_close,
},
[VFIO_CCW_STATE_CP_PENDING] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
@ -422,5 +447,6 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_request,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
[VFIO_CCW_EVENT_OPEN] = fsm_notoper,
[VFIO_CCW_EVENT_CLOSE] = fsm_close,
},
};

14
drivers/s390/cio/vfio_ccw_ops.c
View File

@ -33,9 +33,7 @@ static int vfio_ccw_mdev_reset(struct vfio_ccw_private *private)
* There are still a lot more instructions need to be handled. We
* should come back here later.
*/
ret = vfio_ccw_sch_quiesce(sch);
if (ret)
return ret;
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
if (!ret)
@ -64,7 +62,6 @@ static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
if (vfio_ccw_mdev_reset(private))
return NOTIFY_BAD;
cp_free(&private->cp);
return NOTIFY_OK;
}
@ -159,15 +156,9 @@ static void vfio_ccw_mdev_remove(struct mdev_device *mdev)
vfio_unregister_group_dev(&private->vdev);
if ((private->state != VFIO_CCW_STATE_NOT_OPER) &&
(private->state != VFIO_CCW_STATE_STANDBY)) {
if (!vfio_ccw_sch_quiesce(private->sch))
private->state = VFIO_CCW_STATE_STANDBY;
/* The state will be NOT_OPER on error. */
}
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
vfio_uninit_group_dev(&private->vdev);
cp_free(&private->cp);
atomic_inc(&private->avail);
}
@ -217,7 +208,6 @@ static void vfio_ccw_mdev_close_device(struct vfio_device *vdev)
/* The state will be NOT_OPER on error. */
}
cp_free(&private->cp);
vfio_ccw_unregister_dev_regions(private);
vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb);
}

1
drivers/s390/cio/vfio_ccw_private.h
View File

@ -143,6 +143,7 @@ enum vfio_ccw_event {
VFIO_CCW_EVENT_INTERRUPT,
VFIO_CCW_EVENT_ASYNC_REQ,
VFIO_CCW_EVENT_OPEN,
VFIO_CCW_EVENT_CLOSE,
/* last element! */
NR_VFIO_CCW_EVENTS
};