[mirror_ubuntu-bionic-kernel.git] / drivers / s390 / cio / vfio_ccw_drv.c

// SPDX-License-Identifier: GPL-2.0
/*
 * 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"

struct workqueue_struct *vfio_ccw_work_q;

/*
 * 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;
			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;
}

static void vfio_ccw_sch_io_todo(struct work_struct *work)
{
	struct vfio_ccw_private *private;
	struct irb *irb;

	private = container_of(work, struct vfio_ccw_private, io_work);
	irb = &private->irb;

	if (scsw_is_solicited(&irb->scsw)) {
		cp_update_scsw(&private->cp, &irb->scsw);
		cp_free(&private->cp);
	}
	memcpy(private->io_region.irb_area, irb, sizeof(*irb));

	if (private->io_trigger)
		eventfd_signal(private->io_trigger, 1);

	if (private->mdev)
		private->state = VFIO_CCW_STATE_IDLE;
}

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

	inc_irq_stat(IRQIO_CIO);
	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
}

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);
	private->state = VFIO_CCW_STATE_NOT_OPER;
	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 = vfio_ccw_mdev_reg(sch);
	if (ret)
		goto out_disable;

	INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
	atomic_set(&private->avail, 1);
	private->state = VFIO_CCW_STATE_STANDBY;

	return 0;

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);

	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)
{
	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
	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)) {
		vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
		goto out_unlock;
	}

	private = dev_get_drvdata(&sch->dev);
	if (private->state == VFIO_CCW_STATE_NOT_OPER) {
		private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
				 VFIO_CCW_STATE_STANDBY;
	}

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;

	vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
	if (!vfio_ccw_work_q)
		return -ENOMEM;

	isc_register(VFIO_CCW_ISC);
	ret = css_driver_register(&vfio_ccw_sch_driver);
	if (ret) {
		isc_unregister(VFIO_CCW_ISC);
		destroy_workqueue(vfio_ccw_work_q);
	}

	return ret;
}

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

MODULE_LICENSE("GPL v2");
Commit	Line	Data
724117b7	1	// SPDX-License-Identifier: GPL-2.0
63f1934d DJS	2	/*
	3	* VFIO based Physical Subchannel device driver
	4	*
	5	* Copyright IBM Corp. 2017
	6	*
	7	* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
	8	* Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
	9	*/
	10
	11	#include <linux/module.h>
	12	#include <linux/init.h>
	13	#include <linux/device.h>
	14	#include <linux/slab.h>
4e149e43 DJS	15	#include <linux/uuid.h>
4e149e43 DJS	16	#include <linux/mdev.h>
63f1934d DJS	17
	18	#include <asm/isc.h>
	19
4e149e43 DJS	20	#include "ioasm.h"
4e149e43 DJS	21	#include "css.h"
63f1934d DJS	22	#include "vfio_ccw_private.h"
63f1934d DJS	23
e5f84dba DJS	24	struct workqueue_struct *vfio_ccw_work_q;
e5f84dba DJS	25
63f1934d DJS	26	/*
	27	* Helpers
	28	*/
84cd8fc4	29	int vfio_ccw_sch_quiesce(struct subchannel *sch)
63f1934d DJS	30	{
	31	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
	32	DECLARE_COMPLETION_ONSTACK(completion);
	33	int iretry, ret = 0;
	34
	35	spin_lock_irq(sch->lock);
	36	if (!sch->schib.pmcw.ena)
	37	goto out_unlock;
	38	ret = cio_disable_subchannel(sch);
	39	if (ret != -EBUSY)
	40	goto out_unlock;
	41
	42	do {
	43	iretry = 255;
	44
	45	ret = cio_cancel_halt_clear(sch, &iretry);
	46	while (ret == -EBUSY) {
	47	/*
	48	* Flush all I/O and wait for
	49	* cancel/halt/clear completion.
	50	*/
	51	private->completion = &completion;
	52	spin_unlock_irq(sch->lock);
	53
	54	wait_for_completion_timeout(&completion, 3*HZ);
	55
	56	spin_lock_irq(sch->lock);
	57	private->completion = NULL;
e5f84dba	58	flush_workqueue(vfio_ccw_work_q);
63f1934d DJS	59	ret = cio_cancel_halt_clear(sch, &iretry);
	60	};
	61
	62	ret = cio_disable_subchannel(sch);
	63	} while (ret == -EBUSY);
63f1934d	64	out_unlock:
bbe37e4c	65	private->state = VFIO_CCW_STATE_NOT_OPER;
63f1934d DJS	66	spin_unlock_irq(sch->lock);
	67	return ret;
	68	}
	69
e5f84dba DJS	70	static void vfio_ccw_sch_io_todo(struct work_struct *work)
	71	{
	72	struct vfio_ccw_private *private;
e5f84dba	73	struct irb *irb;
4e149e43	74
e5f84dba DJS	75	private = container_of(work, struct vfio_ccw_private, io_work);
e5f84dba DJS	76	irb = &private->irb;
4e149e43	77
e5f84dba DJS	78	if (scsw_is_solicited(&irb->scsw)) {
	79	cp_update_scsw(&private->cp, &irb->scsw);
	80	cp_free(&private->cp);
	81	}
	82	memcpy(private->io_region.irb_area, irb, sizeof(*irb));
	83
	84	if (private->io_trigger)
	85	eventfd_signal(private->io_trigger, 1);
4e149e43	86
bbe37e4c DJS	87	if (private->mdev)
bbe37e4c DJS	88	private->state = VFIO_CCW_STATE_IDLE;
4e149e43 DJS	89	}
4e149e43 DJS	90
63f1934d DJS	91	/*
	92	* Css driver callbacks
	93	*/
	94	static void vfio_ccw_sch_irq(struct subchannel *sch)
	95	{
	96	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
	97
	98	inc_irq_stat(IRQIO_CIO);
bbe37e4c	99	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
63f1934d DJS	100	}
	101
	102	static int vfio_ccw_sch_probe(struct subchannel *sch)
	103	{
	104	struct pmcw *pmcw = &sch->schib.pmcw;
	105	struct vfio_ccw_private *private;
	106	int ret;
	107
	108	if (pmcw->qf) {
	109	dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
	110	dev_name(&sch->dev));
	111	return -ENODEV;
	112	}
	113
	114	private = kzalloc(sizeof(*private), GFP_KERNEL \| GFP_DMA);
	115	if (!private)
	116	return -ENOMEM;
	117	private->sch = sch;
	118	dev_set_drvdata(&sch->dev, private);
	119
	120	spin_lock_irq(sch->lock);
bbe37e4c	121	private->state = VFIO_CCW_STATE_NOT_OPER;
63f1934d DJS	122	sch->isc = VFIO_CCW_ISC;
	123	ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
	124	spin_unlock_irq(sch->lock);
	125	if (ret)
	126	goto out_free;
	127
84cd8fc4 DJS	128	ret = vfio_ccw_mdev_reg(sch);
84cd8fc4 DJS	129	if (ret)
36f6237e	130	goto out_disable;
84cd8fc4	131
e5f84dba	132	INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
84cd8fc4	133	atomic_set(&private->avail, 1);
bbe37e4c	134	private->state = VFIO_CCW_STATE_STANDBY;
84cd8fc4	135
63f1934d DJS	136	return 0;
	137
	138	out_disable:
	139	cio_disable_subchannel(sch);
	140	out_free:
	141	dev_set_drvdata(&sch->dev, NULL);
	142	kfree(private);
	143	return ret;
	144	}
	145
	146	static int vfio_ccw_sch_remove(struct subchannel *sch)
	147	{
	148	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
	149
	150	vfio_ccw_sch_quiesce(sch);
	151
84cd8fc4 DJS	152	vfio_ccw_mdev_unreg(sch);
84cd8fc4 DJS	153
63f1934d DJS	154	dev_set_drvdata(&sch->dev, NULL);
	155
	156	kfree(private);
	157
	158	return 0;
	159	}
	160
	161	static void vfio_ccw_sch_shutdown(struct subchannel *sch)
	162	{
	163	vfio_ccw_sch_quiesce(sch);
	164	}
	165
	166	/**
	167	* vfio_ccw_sch_event - process subchannel event
	168	* @sch: subchannel
	169	* @process: non-zero if function is called in process context
	170	*
	171	* An unspecified event occurred for this subchannel. Adjust data according
	172	* to the current operational state of the subchannel. Return zero when the
	173	* event has been handled sufficiently or -EAGAIN when this function should
	174	* be called again in process context.
	175	*/
	176	static int vfio_ccw_sch_event(struct subchannel *sch, int process)
	177	{
bbe37e4c	178	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
63f1934d DJS	179	unsigned long flags;
	180
	181	spin_lock_irqsave(sch->lock, flags);
	182	if (!device_is_registered(&sch->dev))
	183	goto out_unlock;
	184
	185	if (work_pending(&sch->todo_work))
	186	goto out_unlock;
	187
	188	if (cio_update_schib(sch)) {
bbe37e4c	189	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
63f1934d DJS	190	goto out_unlock;
	191	}
	192
bbe37e4c DJS	193	private = dev_get_drvdata(&sch->dev);
	194	if (private->state == VFIO_CCW_STATE_NOT_OPER) {
	195	private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
	196	VFIO_CCW_STATE_STANDBY;
	197	}
	198
63f1934d DJS	199	out_unlock:
	200	spin_unlock_irqrestore(sch->lock, flags);
	201
	202	return 0;
	203	}
	204
	205	static struct css_device_id vfio_ccw_sch_ids[] = {
	206	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
	207	{ /* end of list */ },
	208	};
	209	MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
	210
	211	static struct css_driver vfio_ccw_sch_driver = {
	212	.drv = {
	213	.name = "vfio_ccw",
	214	.owner = THIS_MODULE,
	215	},
	216	.subchannel_type = vfio_ccw_sch_ids,
	217	.irq = vfio_ccw_sch_irq,
	218	.probe = vfio_ccw_sch_probe,
	219	.remove = vfio_ccw_sch_remove,
	220	.shutdown = vfio_ccw_sch_shutdown,
	221	.sch_event = vfio_ccw_sch_event,
	222	};
	223
	224	static int __init vfio_ccw_sch_init(void)
	225	{
	226	int ret;
	227
e5f84dba DJS	228	vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
	229	if (!vfio_ccw_work_q)
	230	return -ENOMEM;
	231
63f1934d DJS	232	isc_register(VFIO_CCW_ISC);
63f1934d DJS	233	ret = css_driver_register(&vfio_ccw_sch_driver);
e5f84dba	234	if (ret) {
63f1934d	235	isc_unregister(VFIO_CCW_ISC);
e5f84dba DJS	236	destroy_workqueue(vfio_ccw_work_q);
e5f84dba DJS	237	}
63f1934d DJS	238
	239	return ret;
	240	}
	241
	242	static void __exit vfio_ccw_sch_exit(void)
	243	{
	244	css_driver_unregister(&vfio_ccw_sch_driver);
	245	isc_unregister(VFIO_CCW_ISC);
e5f84dba	246	destroy_workqueue(vfio_ccw_work_q);
63f1934d DJS	247	}
	248	module_init(vfio_ccw_sch_init);
	249	module_exit(vfio_ccw_sch_exit);
	250
	251	MODULE_LICENSE("GPL v2");