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Commit 84cd8fc4 authored by Dong Jia Shi's avatar Dong Jia Shi Committed by Cornelia Huck
Browse files

vfio: ccw: register vfio_ccw to the mediated device framework 



To make vfio support subchannel devices, we need to leverage the
mediated device framework to create a mediated device for the
subchannel device.

This registers the subchannel device to the mediated device
framework during probe to enable mediated device creation.

Reviewed-by: default avatarPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: default avatarDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Message-Id: <20170317031743.40128-7-bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent 0a19e61e

arch/s390/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -675,7 +675,7 @@ config EADM_SCH 
config VFIO_CCW

	def_tristate n

	prompt "Support for VFIO-CCW subchannels"

	depends on S390_CCW_IOMMU && VFIO

	depends on S390_CCW_IOMMU && VFIO_MDEV

	help

	  This driver allows usage of I/O subchannels via VFIO-CCW.

drivers/s390/cio/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -18,5 +18,5 @@ obj-$(CONFIG_CCWGROUP) += ccwgroup.o 
qdio-objs := qdio_main.o qdio_thinint.o qdio_debug.o qdio_setup.o

obj-$(CONFIG_QDIO) += qdio.o



vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o

vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o

obj-$(CONFIG_VFIO_CCW) += vfio_ccw.o

drivers/s390/cio/vfio_ccw_drv.c

+11 −1
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ 
/*

 * Helpers

 */

static int vfio_ccw_sch_quiesce(struct subchannel *sch)

int vfio_ccw_sch_quiesce(struct subchannel *sch)

{

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

	DECLARE_COMPLETION_ONSTACK(completion);
@@ -152,8 +152,16 @@ static int vfio_ccw_sch_probe(struct subchannel *sch) 
	if (ret)

		goto out_disable;



	ret = vfio_ccw_mdev_reg(sch);

	if (ret)

		goto out_rm_group;



	atomic_set(&private->avail, 1);



	return 0;



out_rm_group:

	sysfs_remove_group(&sch->dev.kobj, &vfio_subchannel_attr_group);

out_disable:

	cio_disable_subchannel(sch);

out_free:
@@ -168,6 +176,8 @@ static int vfio_ccw_sch_remove(struct subchannel *sch) 


	vfio_ccw_sch_quiesce(sch);



	vfio_ccw_mdev_unreg(sch);



	sysfs_remove_group(&sch->dev.kobj, &vfio_subchannel_attr_group);



	dev_set_drvdata(&sch->dev, NULL);

drivers/s390/cio/vfio_ccw_ops.c

0 → 100644
+147 −0
Original line number Diff line number Diff line 
/*

 * Physical device callbacks for vfio_ccw

 *

 * Copyright IBM Corp. 2017

 *

 * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>

 *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>

 */



#include <linux/vfio.h>

#include <linux/mdev.h>



#include "vfio_ccw_private.h"



static int vfio_ccw_mdev_notifier(struct notifier_block *nb,

				  unsigned long action,

				  void *data)

{

	struct vfio_ccw_private *private =

		container_of(nb, struct vfio_ccw_private, nb);



	if (!private)

		return NOTIFY_STOP;



	/*

	 * TODO:

	 * Vendor drivers MUST unpin pages in response to an

	 * invalidation.

	 */

	if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP)

		return NOTIFY_BAD;



	return NOTIFY_DONE;

}



static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)

{

	return sprintf(buf, "I/O subchannel (Non-QDIO)\n");

}

MDEV_TYPE_ATTR_RO(name);



static ssize_t device_api_show(struct kobject *kobj, struct device *dev,

			       char *buf)

{

	return sprintf(buf, "%s\n", VFIO_DEVICE_API_CCW_STRING);

}

MDEV_TYPE_ATTR_RO(device_api);



static ssize_t available_instances_show(struct kobject *kobj,

					struct device *dev, char *buf)

{

	struct vfio_ccw_private *private = dev_get_drvdata(dev);



	return sprintf(buf, "%d\n", atomic_read(&private->avail));

}

MDEV_TYPE_ATTR_RO(available_instances);



static struct attribute *mdev_types_attrs[] = {

	&mdev_type_attr_name.attr,

	&mdev_type_attr_device_api.attr,

	&mdev_type_attr_available_instances.attr,

	NULL,

};



static struct attribute_group mdev_type_group = {

	.name  = "io",

	.attrs = mdev_types_attrs,

};



struct attribute_group *mdev_type_groups[] = {

	&mdev_type_group,

	NULL,

};



static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)

{

	struct vfio_ccw_private *private =

		dev_get_drvdata(mdev_parent_dev(mdev));



	if (atomic_dec_if_positive(&private->avail) < 0)

		return -EPERM;



	private->mdev = mdev;



	return 0;

}



static int vfio_ccw_mdev_remove(struct mdev_device *mdev)

{

	struct vfio_ccw_private *private;

	struct subchannel *sch;

	int ret;



	private = dev_get_drvdata(mdev_parent_dev(mdev));

	sch = private->sch;

	ret = vfio_ccw_sch_quiesce(sch);

	if (ret)

		return ret;

	ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);

	if (ret)

		return ret;



	private->mdev = NULL;

	atomic_inc(&private->avail);



	return 0;

}



static int vfio_ccw_mdev_open(struct mdev_device *mdev)

{

	struct vfio_ccw_private *private =

		dev_get_drvdata(mdev_parent_dev(mdev));

	unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;



	private->nb.notifier_call = vfio_ccw_mdev_notifier;



	return vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,

				      &events, &private->nb);

}



void vfio_ccw_mdev_release(struct mdev_device *mdev)

{

	struct vfio_ccw_private *private =

		dev_get_drvdata(mdev_parent_dev(mdev));



	vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,

				 &private->nb);

}



static const struct mdev_parent_ops vfio_ccw_mdev_ops = {

	.owner			= THIS_MODULE,

	.supported_type_groups  = mdev_type_groups,

	.create			= vfio_ccw_mdev_create,

	.remove			= vfio_ccw_mdev_remove,

	.open			= vfio_ccw_mdev_open,

	.release		= vfio_ccw_mdev_release,

};



int vfio_ccw_mdev_reg(struct subchannel *sch)

{

	return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);

}



void vfio_ccw_mdev_unreg(struct subchannel *sch)

{

	mdev_unregister_device(&sch->dev);

}

drivers/s390/cio/vfio_ccw_private.h

+11 −0
Original line number Diff line number Diff line
@@ -16,10 +16,21 @@ 
 * struct vfio_ccw_private

 * @sch: pointer to the subchannel

 * @completion: synchronization helper of the I/O completion

 * @avail: available for creating a mediated device

 * @mdev: pointer to the mediated device

 * @nb: notifier for vfio events

 */

struct vfio_ccw_private {

	struct subchannel	*sch;

	struct completion	*completion;

	atomic_t		avail;

	struct mdev_device	*mdev;

	struct notifier_block	nb;

} __aligned(8);



extern int vfio_ccw_mdev_reg(struct subchannel *sch);

extern void vfio_ccw_mdev_unreg(struct subchannel *sch);



extern int vfio_ccw_sch_quiesce(struct subchannel *sch);



#endif