drivers/s390/cio/vfio_ccw_drv.c - linux - Git at Google

 /*
  * VFIO based Physical Subchannel device driver
  *
  * Copyright IBM Corp. 2017
  *
  * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
  *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/uuid.h>
 #include <linux/mdev.h>

 #include <asm/isc.h>

 #include "ioasm.h"
 #include "css.h"
 #include "vfio_ccw_private.h"

 /*
  * Helpers
  */
 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;
 			ret = cio_cancel_halt_clear(sch, &iretry);
 		};

 		ret = cio_disable_subchannel(sch);
 	} while (ret == -EBUSY);

 out_unlock:
 	spin_unlock_irq(sch->lock);
 	return ret;
 }

 static int doing_io(struct vfio_ccw_private *private, u32 intparm)
 {
 	return (private->intparm == intparm);
 }

 static int vfio_ccw_sch_io_helper(struct vfio_ccw_private *private)
 {
 	struct subchannel *sch;
 	union orb *orb;
 	int ccode;
 	__u8 lpm;
 	u32 intparm;

 	sch = private->sch;

 	orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm);

 	/* Issue "Start Subchannel" */
 	ccode = ssch(sch->schid, orb);

 	switch (ccode) {
 	case 0:
 		/*
 		 * Initialize device status information
 		 */
 		sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
 		break;
 	case 1:		/* Status pending */
 	case 2:		/* Busy */
 		return -EBUSY;
 	case 3:		/* Device/path not operational */
 	{
 		lpm = orb->cmd.lpm;
 		if (lpm != 0)
 			sch->lpm &= ~lpm;
 		else
 			sch->lpm = 0;

 		if (cio_update_schib(sch))
 			return -ENODEV;

 		return sch->lpm ? -EACCES : -ENODEV;
 	}
 	default:
 		return ccode;
 	}

 	intparm = (u32)(addr_t)sch;
 	private->intparm = 0;
 	wait_event(private->wait_q, doing_io(private, intparm));

 	if (scsw_is_solicited(&private->irb.scsw))
 		cp_update_scsw(&private->cp, &private->irb.scsw);

 	return 0;
 }

 /* Deal with the ccw command request from the userspace. */
 int vfio_ccw_sch_cmd_request(struct vfio_ccw_private *private)
 {
 	struct mdev_device *mdev = private->mdev;
 	union orb *orb;
 	union scsw *scsw = &private->scsw;
 	struct irb *irb = &private->irb;
 	struct ccw_io_region *io_region = &private->io_region;
 	int ret;

 	memcpy(scsw, io_region->scsw_area, sizeof(*scsw));

 	if (scsw->cmd.fctl & SCSW_FCTL_START_FUNC) {
 		orb = (union orb *)io_region->orb_area;

 		ret = cp_init(&private->cp, mdev_dev(mdev), orb);
 		if (ret)
 			return ret;

 		ret = cp_prefetch(&private->cp);
 		if (ret) {
 			cp_free(&private->cp);
 			return ret;
 		}

 		/* Start channel program and wait for I/O interrupt. */
 		ret = vfio_ccw_sch_io_helper(private);
 		if (!ret) {
 			/* Get irb info and copy it to irb_area. */
 			memcpy(io_region->irb_area, irb, sizeof(*irb));
 		}

 		cp_free(&private->cp);
 	} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
 		/* XXX: Handle halt. */
 		ret = -EOPNOTSUPP;
 	} else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
 		/* XXX: Handle clear. */
 		ret = -EOPNOTSUPP;
 	} else {
 		ret = -EOPNOTSUPP;
 	}

 	return ret;
 }

 /*
  * Sysfs interfaces
  */
 static ssize_t chpids_show(struct device *dev,
 			   struct device_attribute *attr,
 			   char *buf)
 {
 	struct subchannel *sch = to_subchannel(dev);
 	struct chsc_ssd_info *ssd = &sch->ssd_info;
 	ssize_t ret = 0;
 	int chp;
 	int mask;

 	for (chp = 0; chp < 8; chp++) {
 		mask = 0x80 >> chp;
 		if (ssd->path_mask & mask)
 			ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
 		else
 			ret += sprintf(buf + ret, "00 ");
 	}
 	ret += sprintf(buf+ret, "\n");
 	return ret;
 }

 static ssize_t pimpampom_show(struct device *dev,
 			      struct device_attribute *attr,
 			      char *buf)
 {
 	struct subchannel *sch = to_subchannel(dev);
 	struct pmcw *pmcw = &sch->schib.pmcw;

 	return sprintf(buf, "%02x %02x %02x\n",
 		       pmcw->pim, pmcw->pam, pmcw->pom);
 }

 static DEVICE_ATTR(chpids, 0444, chpids_show, NULL);
 static DEVICE_ATTR(pimpampom, 0444, pimpampom_show, NULL);

 static struct attribute *vfio_subchannel_attrs[] = {
 	&dev_attr_chpids.attr,
 	&dev_attr_pimpampom.attr,
 	NULL,
 };

 static struct attribute_group vfio_subchannel_attr_group = {
 	.attrs = vfio_subchannel_attrs,
 };

 /*
  * Css driver callbacks
  */
 static void vfio_ccw_sch_irq(struct subchannel *sch)
 {
 	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 	struct irb *irb;

 	inc_irq_stat(IRQIO_CIO);

 	if (!private)
 		return;

 	irb = this_cpu_ptr(&cio_irb);
 	memcpy(&private->irb, irb, sizeof(*irb));
 	private->intparm = (u32)(addr_t)sch;
 	wake_up(&private->wait_q);

 	if (private->completion)
 		complete(private->completion);
 }

 static int vfio_ccw_sch_probe(struct subchannel *sch)
 {
 	struct pmcw *pmcw = &sch->schib.pmcw;
 	struct vfio_ccw_private *private;
 	int ret;

 	if (pmcw->qf) {
 		dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
 			 dev_name(&sch->dev));
 		return -ENODEV;
 	}

 	private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
 	if (!private)
 		return -ENOMEM;
 	private->sch = sch;
 	dev_set_drvdata(&sch->dev, private);

 	spin_lock_irq(sch->lock);
 	sch->isc = VFIO_CCW_ISC;
 	ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
 	spin_unlock_irq(sch->lock);
 	if (ret)
 		goto out_free;

 	ret = sysfs_create_group(&sch->dev.kobj, &vfio_subchannel_attr_group);
 	if (ret)
 		goto out_disable;

 	ret = vfio_ccw_mdev_reg(sch);
 	if (ret)
 		goto out_rm_group;

 	init_waitqueue_head(&private->wait_q);
 	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:
 	dev_set_drvdata(&sch->dev, NULL);
 	kfree(private);
 	return ret;
 }

 static int vfio_ccw_sch_remove(struct subchannel *sch)
 {
 	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);

 	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);

 	kfree(private);

 	return 0;
 }

 static void vfio_ccw_sch_shutdown(struct subchannel *sch)
 {
 	vfio_ccw_sch_quiesce(sch);
 }

 /**
  * vfio_ccw_sch_event - process subchannel event
  * @sch: subchannel
  * @process: non-zero if function is called in process context
  *
  * An unspecified event occurred for this subchannel. Adjust data according
  * to the current operational state of the subchannel. Return zero when the
  * event has been handled sufficiently or -EAGAIN when this function should
  * be called again in process context.
  */
 static int vfio_ccw_sch_event(struct subchannel *sch, int process)
 {
 	unsigned long flags;

 	spin_lock_irqsave(sch->lock, flags);
 	if (!device_is_registered(&sch->dev))
 		goto out_unlock;

 	if (work_pending(&sch->todo_work))
 		goto out_unlock;

 	if (cio_update_schib(sch)) {
 		/* Not operational. */
 		css_sched_sch_todo(sch, SCH_TODO_UNREG);

 		/*
 		 * TODO:
 		 * Probably we should send the machine check to the guest.
 		 */
 		goto out_unlock;
 	}

 out_unlock:
 	spin_unlock_irqrestore(sch->lock, flags);

 	return 0;
 }

 static struct css_device_id vfio_ccw_sch_ids[] = {
 	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
 	{ /* end of list */ },
 };
 MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);

 static struct css_driver vfio_ccw_sch_driver = {
 	.drv = {
 		.name = "vfio_ccw",
 		.owner = THIS_MODULE,
 	},
 	.subchannel_type = vfio_ccw_sch_ids,
 	.irq = vfio_ccw_sch_irq,
 	.probe = vfio_ccw_sch_probe,
 	.remove = vfio_ccw_sch_remove,
 	.shutdown = vfio_ccw_sch_shutdown,
 	.sch_event = vfio_ccw_sch_event,
 };

 static int __init vfio_ccw_sch_init(void)
 {
 	int ret;

 	isc_register(VFIO_CCW_ISC);
 	ret = css_driver_register(&vfio_ccw_sch_driver);
 	if (ret)
 		isc_unregister(VFIO_CCW_ISC);

 	return ret;
 }

 static void __exit vfio_ccw_sch_exit(void)
 {
 	css_driver_unregister(&vfio_ccw_sch_driver);
 	isc_unregister(VFIO_CCW_ISC);
 }
 module_init(vfio_ccw_sch_init);
 module_exit(vfio_ccw_sch_exit);

 MODULE_LICENSE("GPL v2");
	/*
	* VFIO based Physical Subchannel device driver
	*
	* Copyright IBM Corp. 2017
	*
	* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
	* Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/device.h>
	#include <linux/slab.h>
	#include <linux/uuid.h>
	#include <linux/mdev.h>

	#include <asm/isc.h>

	#include "ioasm.h"
	#include "css.h"
	#include "vfio_ccw_private.h"

	/*
	* Helpers
	*/
	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;
	ret = cio_cancel_halt_clear(sch, &iretry);
	};

	ret = cio_disable_subchannel(sch);
	} while (ret == -EBUSY);

	out_unlock:
	spin_unlock_irq(sch->lock);
	return ret;
	}

	static int doing_io(struct vfio_ccw_private *private, u32 intparm)
	{
	return (private->intparm == intparm);
	}

	static int vfio_ccw_sch_io_helper(struct vfio_ccw_private *private)
	{
	struct subchannel *sch;
	union orb *orb;
	int ccode;
	__u8 lpm;
	u32 intparm;

	sch = private->sch;

	orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm);

	/* Issue "Start Subchannel" */
	ccode = ssch(sch->schid, orb);

	switch (ccode) {
	case 0:
	/*
	* Initialize device status information
	*/
	sch->schib.scsw.cmd.actl \|= SCSW_ACTL_START_PEND;
	break;
	case 1: /* Status pending */
	case 2: /* Busy */
	return -EBUSY;
	case 3: /* Device/path not operational */
	{
	lpm = orb->cmd.lpm;
	if (lpm != 0)
	sch->lpm &= ~lpm;
	else
	sch->lpm = 0;

	if (cio_update_schib(sch))
	return -ENODEV;

	return sch->lpm ? -EACCES : -ENODEV;
	}
	default:
	return ccode;
	}

	intparm = (u32)(addr_t)sch;
	private->intparm = 0;
	wait_event(private->wait_q, doing_io(private, intparm));

	if (scsw_is_solicited(&private->irb.scsw))
	cp_update_scsw(&private->cp, &private->irb.scsw);

	return 0;
	}

	/* Deal with the ccw command request from the userspace. */
	int vfio_ccw_sch_cmd_request(struct vfio_ccw_private *private)
	{
	struct mdev_device *mdev = private->mdev;
	union orb *orb;
	union scsw *scsw = &private->scsw;
	struct irb *irb = &private->irb;
	struct ccw_io_region *io_region = &private->io_region;
	int ret;

	memcpy(scsw, io_region->scsw_area, sizeof(*scsw));

	if (scsw->cmd.fctl & SCSW_FCTL_START_FUNC) {
	orb = (union orb *)io_region->orb_area;

	ret = cp_init(&private->cp, mdev_dev(mdev), orb);
	if (ret)
	return ret;

	ret = cp_prefetch(&private->cp);
	if (ret) {
	cp_free(&private->cp);
	return ret;
	}

	/* Start channel program and wait for I/O interrupt. */
	ret = vfio_ccw_sch_io_helper(private);
	if (!ret) {
	/* Get irb info and copy it to irb_area. */
	memcpy(io_region->irb_area, irb, sizeof(*irb));
	}

	cp_free(&private->cp);
	} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
	/* XXX: Handle halt. */
	ret = -EOPNOTSUPP;
	} else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
	/* XXX: Handle clear. */
	ret = -EOPNOTSUPP;
	} else {
	ret = -EOPNOTSUPP;
	}

	return ret;
	}

	/*
	* Sysfs interfaces
	*/
	static ssize_t chpids_show(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct subchannel *sch = to_subchannel(dev);
	struct chsc_ssd_info *ssd = &sch->ssd_info;
	ssize_t ret = 0;
	int chp;
	int mask;

	for (chp = 0; chp < 8; chp++) {
	mask = 0x80 >> chp;
	if (ssd->path_mask & mask)
	ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
	else
	ret += sprintf(buf + ret, "00 ");
	}
	ret += sprintf(buf+ret, "\n");
	return ret;
	}

	static ssize_t pimpampom_show(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct subchannel *sch = to_subchannel(dev);
	struct pmcw *pmcw = &sch->schib.pmcw;

	return sprintf(buf, "%02x %02x %02x\n",
	pmcw->pim, pmcw->pam, pmcw->pom);
	}

	static DEVICE_ATTR(chpids, 0444, chpids_show, NULL);
	static DEVICE_ATTR(pimpampom, 0444, pimpampom_show, NULL);

	static struct attribute *vfio_subchannel_attrs[] = {
	&dev_attr_chpids.attr,
	&dev_attr_pimpampom.attr,
	NULL,
	};

	static struct attribute_group vfio_subchannel_attr_group = {
	.attrs = vfio_subchannel_attrs,
	};

	/*
	* Css driver callbacks
	*/
	static void vfio_ccw_sch_irq(struct subchannel *sch)
	{
	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
	struct irb *irb;

	inc_irq_stat(IRQIO_CIO);

	if (!private)
	return;

	irb = this_cpu_ptr(&cio_irb);
	memcpy(&private->irb, irb, sizeof(*irb));
	private->intparm = (u32)(addr_t)sch;
	wake_up(&private->wait_q);

	if (private->completion)
	complete(private->completion);
	}

	static int vfio_ccw_sch_probe(struct subchannel *sch)
	{
	struct pmcw *pmcw = &sch->schib.pmcw;
	struct vfio_ccw_private *private;
	int ret;

	if (pmcw->qf) {
	dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
	dev_name(&sch->dev));
	return -ENODEV;
	}

	private = kzalloc(sizeof(*private), GFP_KERNEL \| GFP_DMA);
	if (!private)
	return -ENOMEM;
	private->sch = sch;
	dev_set_drvdata(&sch->dev, private);

	spin_lock_irq(sch->lock);
	sch->isc = VFIO_CCW_ISC;
	ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
	spin_unlock_irq(sch->lock);
	if (ret)
	goto out_free;

	ret = sysfs_create_group(&sch->dev.kobj, &vfio_subchannel_attr_group);
	if (ret)
	goto out_disable;

	ret = vfio_ccw_mdev_reg(sch);
	if (ret)
	goto out_rm_group;

	init_waitqueue_head(&private->wait_q);
	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:
	dev_set_drvdata(&sch->dev, NULL);
	kfree(private);
	return ret;
	}

	static int vfio_ccw_sch_remove(struct subchannel *sch)
	{
	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);

	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);

	kfree(private);

	return 0;
	}

	static void vfio_ccw_sch_shutdown(struct subchannel *sch)
	{
	vfio_ccw_sch_quiesce(sch);
	}

	/**
	* vfio_ccw_sch_event - process subchannel event
	* @sch: subchannel
	* @process: non-zero if function is called in process context
	*
	* An unspecified event occurred for this subchannel. Adjust data according
	* to the current operational state of the subchannel. Return zero when the
	* event has been handled sufficiently or -EAGAIN when this function should
	* be called again in process context.
	*/
	static int vfio_ccw_sch_event(struct subchannel *sch, int process)
	{
	unsigned long flags;

	spin_lock_irqsave(sch->lock, flags);
	if (!device_is_registered(&sch->dev))
	goto out_unlock;

	if (work_pending(&sch->todo_work))
	goto out_unlock;

	if (cio_update_schib(sch)) {
	/* Not operational. */
	css_sched_sch_todo(sch, SCH_TODO_UNREG);

	/*
	* TODO:
	* Probably we should send the machine check to the guest.
	*/
	goto out_unlock;
	}

	out_unlock:
	spin_unlock_irqrestore(sch->lock, flags);

	return 0;
	}

	static struct css_device_id vfio_ccw_sch_ids[] = {
	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
	{ /* end of list */ },
	};
	MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);

	static struct css_driver vfio_ccw_sch_driver = {
	.drv = {
	.name = "vfio_ccw",
	.owner = THIS_MODULE,
	},
	.subchannel_type = vfio_ccw_sch_ids,
	.irq = vfio_ccw_sch_irq,
	.probe = vfio_ccw_sch_probe,
	.remove = vfio_ccw_sch_remove,
	.shutdown = vfio_ccw_sch_shutdown,
	.sch_event = vfio_ccw_sch_event,
	};

	static int __init vfio_ccw_sch_init(void)
	{
	int ret;

	isc_register(VFIO_CCW_ISC);
	ret = css_driver_register(&vfio_ccw_sch_driver);
	if (ret)
	isc_unregister(VFIO_CCW_ISC);

	return ret;
	}

	static void __exit vfio_ccw_sch_exit(void)
	{
	css_driver_unregister(&vfio_ccw_sch_driver);
	isc_unregister(VFIO_CCW_ISC);
	}
	module_init(vfio_ccw_sch_init);
	module_exit(vfio_ccw_sch_exit);

	MODULE_LICENSE("GPL v2");