Commit 3f02cb2f authored by Farhan Ali's avatar Farhan Ali Committed by Cornelia Huck
Browse files

vfio-ccw: Wire up the CRW irq and CRW region 



Use the IRQ to notify userspace that there is a CRW
pending in the region, related to path-availability
changes on the passthrough subchannel.

Signed-off-by: default avatarFarhan Ali <alifm@linux.ibm.com>
Signed-off-by: default avatarEric Farman <farman@linux.ibm.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Message-Id: <20200505122745.53208-8-farman@linux.ibm.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent d8cac29b

drivers/s390/cio/vfio_ccw_chp.c

+17 −0
Original line number Diff line number Diff line
@@ -82,14 +82,24 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio_ccw_private *private, 
	unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;

	loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;

	struct ccw_crw_region *region;

	struct vfio_ccw_crw *crw;

	int ret;



	if (pos + count > sizeof(*region))

		return -EINVAL;



	crw = list_first_entry_or_null(&private->crw,

				       struct vfio_ccw_crw, next);



	if (crw)

		list_del(&crw->next);



	mutex_lock(&private->io_mutex);

	region = private->region[i].data;



	if (crw)

		memcpy(&region->crw, &crw->crw, sizeof(region->crw));



	if (copy_to_user(buf, (void *)region + pos, count))

		ret = -EFAULT;

	else
@@ -98,6 +108,13 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio_ccw_private *private, 
	region->crw = 0;



	mutex_unlock(&private->io_mutex);



	kfree(crw);



	/* Notify the guest if more CRWs are on our queue */

	if (!list_empty(&private->crw) && private->crw_trigger)

		eventfd_signal(private->crw_trigger, 1);



	return ret;

}

drivers/s390/cio/vfio_ccw_drv.c

+49 −0
Original line number Diff line number Diff line
@@ -108,6 +108,16 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work) 
		eventfd_signal(private->io_trigger, 1);

}



static void vfio_ccw_crw_todo(struct work_struct *work)

{

	struct vfio_ccw_private *private;



	private = container_of(work, struct vfio_ccw_private, crw_work);



	if (!list_empty(&private->crw) && private->crw_trigger)

		eventfd_signal(private->crw_trigger, 1);

}



/*

 * Css driver callbacks

 */
@@ -186,7 +196,9 @@ static int vfio_ccw_sch_probe(struct subchannel *sch) 
	if (ret)

		goto out_free;



	INIT_LIST_HEAD(&private->crw);

	INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);

	INIT_WORK(&private->crw_work, vfio_ccw_crw_todo);

	atomic_set(&private->avail, 1);

	private->state = VFIO_CCW_STATE_STANDBY;
@@ -217,9 +229,15 @@ out_free: 
static int vfio_ccw_sch_remove(struct subchannel *sch)

{

	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);

	struct vfio_ccw_crw *crw, *temp;



	vfio_ccw_sch_quiesce(sch);



	list_for_each_entry_safe(crw, temp, &private->crw, next) {

		list_del(&crw->next);

		kfree(crw);

	}



	vfio_ccw_mdev_unreg(sch);



	dev_set_drvdata(&sch->dev, NULL);
@@ -281,6 +299,33 @@ out_unlock: 
	return rc;

}



static void vfio_ccw_queue_crw(struct vfio_ccw_private *private,

			       unsigned int rsc,

			       unsigned int erc,

			       unsigned int rsid)

{

	struct vfio_ccw_crw *crw;



	/*

	 * If unable to allocate a CRW, just drop the event and

	 * carry on.  The guest will either see a later one or

	 * learn when it issues its own store subchannel.

	 */

	crw = kzalloc(sizeof(*crw), GFP_ATOMIC);

	if (!crw)

		return;



	/*

	 * Build the CRW based on the inputs given to us.

	 */

	crw->crw.rsc = rsc;

	crw->crw.erc = erc;

	crw->crw.rsid = rsid;



	list_add_tail(&crw->next, &private->crw);

	queue_work(vfio_ccw_work_q, &private->crw_work);

}



static int vfio_ccw_chp_event(struct subchannel *sch,

			      struct chp_link *link, int event)

{
@@ -311,6 +356,8 @@ static int vfio_ccw_chp_event(struct subchannel *sch, 
		/* Path is gone */

		if (sch->schib.pmcw.lpum & mask)

			cio_cancel_halt_clear(sch, &retry);

		vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_PERRN,

				   link->chpid.id);

		break;

	case CHP_VARY_ON:

		/* Path logically turned on */
@@ -320,6 +367,8 @@ static int vfio_ccw_chp_event(struct subchannel *sch, 
	case CHP_ONLINE:

		/* Path became available */

		sch->lpm |= mask & sch->opm;

		vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_INIT,

				   link->chpid.id);

		break;

	}

drivers/s390/cio/vfio_ccw_private.h

+8 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/eventfd.h>

#include <linux/workqueue.h>

#include <linux/vfio_ccw.h>

#include <asm/crw.h>

#include <asm/debug.h>



#include "css.h"
@@ -59,6 +60,11 @@ int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private); 
int vfio_ccw_register_schib_dev_regions(struct vfio_ccw_private *private);

int vfio_ccw_register_crw_dev_regions(struct vfio_ccw_private *private);



struct vfio_ccw_crw {

	struct list_head	next;

	struct crw		crw;

};



/**

 * struct vfio_ccw_private

 * @sch: pointer to the subchannel
@@ -98,10 +104,12 @@ struct vfio_ccw_private { 
	struct channel_program	cp;

	struct irb		irb;

	union scsw		scsw;

	struct list_head	crw;



	struct eventfd_ctx	*io_trigger;

	struct eventfd_ctx	*crw_trigger;

	struct work_struct	io_work;

	struct work_struct	crw_work;

} __aligned(8);



extern int vfio_ccw_mdev_reg(struct subchannel *sch);

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