Commit f4b4ed44 authored by Eric Farman's avatar Eric Farman Committed by Alex Williamson
Browse files

vfio/ccw: Create a CLOSE FSM event 



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: default avatarEric Farman <farman@linux.ibm.com>
Reviewed-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20220707135737.720765-10-farman@linux.ibm.com


Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 62ec0d49

drivers/s390/cio/vfio_ccw_drv.c

+5 −12
Original line number Diff line number Diff line
@@ -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);

}



/**

drivers/s390/cio/vfio_ccw_fsm.c

+26 −0
Original line number Diff line number Diff line
@@ -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,

	},

};

drivers/s390/cio/vfio_ccw_ops.c

+2 −12
Original line number Diff line number Diff line
@@ -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);

}

drivers/s390/cio/vfio_ccw_private.h

+1 −0
Original line number Diff line number Diff line
@@ -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

};