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Subject[PATCH 08/10] vfio: ccw: Handling reset and shutdown with states
Date
Two new events, VFIO_CCW_EVENT_ONLINE and VFIO_CCW_EVENT_OFFLINE
allow to handle the enabling and disabling of a Sub Channel and
the shutdown, quiesce and reset operations are changed accordingly.

Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
---
drivers/s390/cio/vfio_ccw_drv.c | 47 ++++++--------------------
drivers/s390/cio/vfio_ccw_fsm.c | 66 +++++++++++++++++++++++++++++++++++++
drivers/s390/cio/vfio_ccw_ops.c | 15 +++------
drivers/s390/cio/vfio_ccw_private.h | 3 ++
4 files changed, 83 insertions(+), 48 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index f6e7def1..7175c64 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -30,41 +30,13 @@ int vfio_ccw_sch_quiesce(struct subchannel *sch)
{
struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
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;
-
- do {
- iretry = 255;
-
- ret = cio_cancel_halt_clear(sch, &iretry);
- while (ret == -EBUSY) {
- /*
- * Flush all I/O and wait for
- * cancel/halt/clear completion.
- */
- private->completion = &completion;
- spin_unlock_irq(sch->lock);
-
- wait_for_completion_timeout(&completion, 3*HZ);
-
- spin_lock_irq(sch->lock);
- private->completion = NULL;
- flush_workqueue(vfio_ccw_work_q);
- ret = cio_cancel_halt_clear(sch, &iretry);
- };
-
- ret = cio_disable_subchannel(sch);
- } while (ret == -EBUSY);
-out_unlock:
- private->state = VFIO_CCW_STATE_NOT_OPER;
- spin_unlock_irq(sch->lock);
- return ret;
+
+ private->completion = &completion;
+ vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_OFFLINE);
+ wait_for_completion(&completion);
+ if (private->state != VFIO_CCW_STATE_STANDBY)
+ return -EFAULT;
+ return 0;
}

static void vfio_ccw_sch_io_todo(struct work_struct *work)
@@ -97,8 +69,6 @@ static void vfio_ccw_sch_irq(struct subchannel *sch)

WARN_ON(work_pending(&private->io_work));
queue_work(vfio_ccw_work_q, &private->io_work);
- if (private->completion)
- complete(private->completion);
}

static int vfio_ccw_sch_probe(struct subchannel *sch)
@@ -132,6 +102,9 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
ret = -EFAULT;
if (private->state != VFIO_CCW_STATE_STANDBY)
goto out_unreg;
+ vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_ONLINE);
+ if (private->state != VFIO_CCW_STATE_IDLE)
+ goto out_unreg;

return 0;

diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index e8fe1e6..444424e 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -68,6 +68,53 @@ static int fsm_notoper(struct vfio_ccw_private *private)
return VFIO_CCW_STATE_NOT_OPER;
}

+static int fsm_online(struct vfio_ccw_private *private)
+{
+ struct subchannel *sch = private->sch;
+ int ret = VFIO_CCW_STATE_IDLE;
+
+ spin_lock_irq(sch->lock);
+ if (cio_enable_subchannel(sch, (u32)(unsigned long)sch))
+ ret = VFIO_CCW_STATE_NOT_OPER;
+ spin_unlock_irq(sch->lock);
+
+ return ret;
+}
+static int fsm_offline(struct vfio_ccw_private *private)
+{
+ struct subchannel *sch = private->sch;
+ int ret = VFIO_CCW_STATE_STANDBY;
+
+ spin_lock_irq(sch->lock);
+ if (cio_disable_subchannel(sch))
+ ret = VFIO_CCW_STATE_NOT_OPER;
+ spin_unlock_irq(sch->lock);
+ if (private->completion)
+ complete(private->completion);
+
+ return ret;
+}
+static int fsm_quiescing(struct vfio_ccw_private *private)
+{
+ struct subchannel *sch = private->sch;
+ int ret = VFIO_CCW_STATE_STANDBY;
+ int iretry = 255;
+
+ spin_lock_irq(sch->lock);
+ ret = cio_cancel_halt_clear(sch, &iretry);
+ if (ret == -EBUSY)
+ ret = VFIO_CCW_STATE_QUIESCING;
+ else if (private->completion)
+ complete(private->completion);
+ spin_unlock_irq(sch->lock);
+ return ret;
+}
+static int fsm_quiescing_done(struct vfio_ccw_private *private)
+{
+ if (private->completion)
+ complete(private->completion);
+ return VFIO_CCW_STATE_STANDBY;
+}
/*
* No operation action.
*/
@@ -189,6 +236,8 @@ static int fsm_init(struct vfio_ccw_private *private)
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_ONLINE] = fsm_nop,
+ [VFIO_CCW_EVENT_OFFLINE] = fsm_nop,
[VFIO_CCW_EVENT_NOT_OPER] = fsm_nop,
[VFIO_CCW_EVENT_SSCH_REQ] = fsm_io_error,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
@@ -196,6 +245,8 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
},
[VFIO_CCW_STATE_STANDBY] = {
[VFIO_CCW_EVENT_INIT] = fsm_nop,
+ [VFIO_CCW_EVENT_ONLINE] = fsm_online,
+ [VFIO_CCW_EVENT_OFFLINE] = fsm_nop,
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_SSCH_REQ] = fsm_io_error,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
@@ -203,6 +254,8 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
},
[VFIO_CCW_STATE_IDLE] = {
[VFIO_CCW_EVENT_INIT] = fsm_nop,
+ [VFIO_CCW_EVENT_ONLINE] = fsm_nop,
+ [VFIO_CCW_EVENT_OFFLINE] = fsm_offline,
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_SSCH_REQ] = fsm_io_request,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
@@ -210,6 +263,8 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
},
[VFIO_CCW_STATE_BOXED] = {
[VFIO_CCW_EVENT_INIT] = fsm_nop,
+ [VFIO_CCW_EVENT_ONLINE] = fsm_nop,
+ [VFIO_CCW_EVENT_OFFLINE] = fsm_quiescing,
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_SSCH_REQ] = fsm_io_busy,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
@@ -217,9 +272,20 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
},
[VFIO_CCW_STATE_BUSY] = {
[VFIO_CCW_EVENT_INIT] = fsm_nop,
+ [VFIO_CCW_EVENT_ONLINE] = fsm_nop,
+ [VFIO_CCW_EVENT_OFFLINE] = fsm_quiescing,
[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_QUIESCING] = {
+ [VFIO_CCW_EVENT_INIT] = fsm_nop,
+ [VFIO_CCW_EVENT_ONLINE] = fsm_nop,
+ [VFIO_CCW_EVENT_OFFLINE] = fsm_nop,
+ [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
+ [VFIO_CCW_EVENT_SSCH_REQ] = fsm_io_busy,
+ [VFIO_CCW_EVENT_INTERRUPT] = fsm_quiescing_done,
+ [VFIO_CCW_EVENT_SCH_EVENT] = fsm_sch_event,
+ },
};
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 78d1925..f0f4071 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -21,21 +21,14 @@ static int vfio_ccw_mdev_reset(struct mdev_device *mdev)

private = dev_get_drvdata(mdev_parent_dev(mdev));
sch = private->sch;
- /*
- * TODO:
- * In the cureent stage, some things like "no I/O running" and "no
- * interrupt pending" are clear, but we are not sure what other state
- * we need to care about.
- * 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_ONLINE);

- ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
- if (!ret)
- private->state = VFIO_CCW_STATE_IDLE;
+ if (!(private->state == VFIO_CCW_STATE_IDLE))
+ ret = -EFAULT;

return ret;
}
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index cacf677..e7ea076 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -68,6 +68,7 @@ enum vfio_ccw_state {
VFIO_CCW_STATE_IDLE,
VFIO_CCW_STATE_BOXED,
VFIO_CCW_STATE_BUSY,
+ VFIO_CCW_STATE_QUIESCING,
/* last element! */
NR_VFIO_CCW_STATES
};
@@ -81,6 +82,8 @@ enum vfio_ccw_event {
VFIO_CCW_EVENT_SSCH_REQ,
VFIO_CCW_EVENT_INTERRUPT,
VFIO_CCW_EVENT_SCH_EVENT,
+ VFIO_CCW_EVENT_ONLINE,
+ VFIO_CCW_EVENT_OFFLINE,
/* last element! */
NR_VFIO_CCW_EVENTS
};
--
2.7.4
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