[linux.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 <[email protected]>
 *            Xiao Feng Ren <[email protected]>
 */

#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;
static struct kmem_cache *vfio_ccw_io_region;

/*
 * 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->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
					       GFP_KERNEL | GFP_DMA);
	if (!private->io_region) {
		kfree(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;

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

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

	return 0;

out_disable:
	cio_disable_subchannel(sch);
out_free:
	dev_set_drvdata(&sch->dev, NULL);
	kmem_cache_free(vfio_ccw_io_region, private->io_region);
	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);

	kmem_cache_free(vfio_ccw_io_region, private->io_region);
	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;
	int rc = -EAGAIN;

	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);
		rc = 0;
		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;
	}
	rc = 0;

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

	return rc;
}

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;

	vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
					sizeof(struct ccw_io_region), 0,
					SLAB_ACCOUNT, 0,
					sizeof(struct ccw_io_region), NULL);
	if (!vfio_ccw_io_region) {
		destroy_workqueue(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);
		kmem_cache_destroy(vfio_ccw_io_region);
		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);
	kmem_cache_destroy(vfio_ccw_io_region);
	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 <[email protected]>
	8	* Xiao Feng Ren <[email protected]>
	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	24	struct workqueue_struct *vfio_ccw_work_q;
52df7837	25	static struct kmem_cache *vfio_ccw_io_region;
e5f84dba	26
63f1934d DJS	27	/*
	28	* Helpers
	29	*/
84cd8fc4	30	int vfio_ccw_sch_quiesce(struct subchannel *sch)
63f1934d DJS	31	{
	32	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
	33	DECLARE_COMPLETION_ONSTACK(completion);
	34	int iretry, ret = 0;
	35
	36	spin_lock_irq(sch->lock);
	37	if (!sch->schib.pmcw.ena)
	38	goto out_unlock;
	39	ret = cio_disable_subchannel(sch);
	40	if (ret != -EBUSY)
	41	goto out_unlock;
	42
	43	do {
	44	iretry = 255;
	45
	46	ret = cio_cancel_halt_clear(sch, &iretry);
	47	while (ret == -EBUSY) {
	48	/*
	49	* Flush all I/O and wait for
	50	* cancel/halt/clear completion.
	51	*/
	52	private->completion = &completion;
	53	spin_unlock_irq(sch->lock);
	54
	55	wait_for_completion_timeout(&completion, 3*HZ);
	56
	57	spin_lock_irq(sch->lock);
	58	private->completion = NULL;
e5f84dba	59	flush_workqueue(vfio_ccw_work_q);
63f1934d DJS	60	ret = cio_cancel_halt_clear(sch, &iretry);
	61	};
	62
	63	ret = cio_disable_subchannel(sch);
	64	} while (ret == -EBUSY);
63f1934d	65	out_unlock:
bbe37e4c	66	private->state = VFIO_CCW_STATE_NOT_OPER;
63f1934d DJS	67	spin_unlock_irq(sch->lock);
	68	return ret;
	69	}
	70
e5f84dba DJS	71	static void vfio_ccw_sch_io_todo(struct work_struct *work)
	72	{
	73	struct vfio_ccw_private *private;
e5f84dba	74	struct irb *irb;
4e149e43	75
e5f84dba DJS	76	private = container_of(work, struct vfio_ccw_private, io_work);
e5f84dba DJS	77	irb = &private->irb;
4e149e43	78
e5f84dba DJS	79	if (scsw_is_solicited(&irb->scsw)) {
	80	cp_update_scsw(&private->cp, &irb->scsw);
	81	cp_free(&private->cp);
	82	}
c98e16b2	83	memcpy(private->io_region->irb_area, irb, sizeof(*irb));
e5f84dba DJS	84
	85	if (private->io_trigger)
	86	eventfd_signal(private->io_trigger, 1);
4e149e43	87
bbe37e4c DJS	88	if (private->mdev)
bbe37e4c DJS	89	private->state = VFIO_CCW_STATE_IDLE;
4e149e43 DJS	90	}
4e149e43 DJS	91
63f1934d DJS	92	/*
	93	* Css driver callbacks
	94	*/
	95	static void vfio_ccw_sch_irq(struct subchannel *sch)
	96	{
	97	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
	98
	99	inc_irq_stat(IRQIO_CIO);
bbe37e4c	100	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
63f1934d DJS	101	}
	102
	103	static int vfio_ccw_sch_probe(struct subchannel *sch)
	104	{
	105	struct pmcw *pmcw = &sch->schib.pmcw;
	106	struct vfio_ccw_private *private;
	107	int ret;
	108
	109	if (pmcw->qf) {
	110	dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
	111	dev_name(&sch->dev));
	112	return -ENODEV;
	113	}
	114
	115	private = kzalloc(sizeof(*private), GFP_KERNEL \| GFP_DMA);
	116	if (!private)
	117	return -ENOMEM;
c98e16b2	118
bf42daed EF	119	private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
bf42daed EF	120	GFP_KERNEL \| GFP_DMA);
c98e16b2 EF	121	if (!private->io_region) {
	122	kfree(private);
	123	return -ENOMEM;
	124	}
	125
63f1934d DJS	126	private->sch = sch;
	127	dev_set_drvdata(&sch->dev, private);
	128
	129	spin_lock_irq(sch->lock);
bbe37e4c	130	private->state = VFIO_CCW_STATE_NOT_OPER;
63f1934d DJS	131	sch->isc = VFIO_CCW_ISC;
	132	ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
	133	spin_unlock_irq(sch->lock);
	134	if (ret)
	135	goto out_free;
	136
e5f84dba	137	INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
84cd8fc4	138	atomic_set(&private->avail, 1);
bbe37e4c	139	private->state = VFIO_CCW_STATE_STANDBY;
84cd8fc4	140
55e93ecd PM	141	ret = vfio_ccw_mdev_reg(sch);
	142	if (ret)
	143	goto out_disable;
	144
63f1934d DJS	145	return 0;
	146
	147	out_disable:
	148	cio_disable_subchannel(sch);
	149	out_free:
	150	dev_set_drvdata(&sch->dev, NULL);
bf42daed	151	kmem_cache_free(vfio_ccw_io_region, private->io_region);
63f1934d DJS	152	kfree(private);
	153	return ret;
	154	}
	155
	156	static int vfio_ccw_sch_remove(struct subchannel *sch)
	157	{
	158	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
	159
	160	vfio_ccw_sch_quiesce(sch);
	161
84cd8fc4 DJS	162	vfio_ccw_mdev_unreg(sch);
84cd8fc4 DJS	163
63f1934d DJS	164	dev_set_drvdata(&sch->dev, NULL);
63f1934d DJS	165
bf42daed	166	kmem_cache_free(vfio_ccw_io_region, private->io_region);
63f1934d DJS	167	kfree(private);
	168
	169	return 0;
	170	}
	171
	172	static void vfio_ccw_sch_shutdown(struct subchannel *sch)
	173	{
	174	vfio_ccw_sch_quiesce(sch);
	175	}
	176
	177	/**
	178	* vfio_ccw_sch_event - process subchannel event
	179	* @sch: subchannel
	180	* @process: non-zero if function is called in process context
	181	*
	182	* An unspecified event occurred for this subchannel. Adjust data according
	183	* to the current operational state of the subchannel. Return zero when the
	184	* event has been handled sufficiently or -EAGAIN when this function should
	185	* be called again in process context.
	186	*/
	187	static int vfio_ccw_sch_event(struct subchannel *sch, int process)
	188	{
bbe37e4c	189	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
63f1934d	190	unsigned long flags;
2c861d89	191	int rc = -EAGAIN;
63f1934d DJS	192
	193	spin_lock_irqsave(sch->lock, flags);
	194	if (!device_is_registered(&sch->dev))
	195	goto out_unlock;
	196
	197	if (work_pending(&sch->todo_work))
	198	goto out_unlock;
	199
	200	if (cio_update_schib(sch)) {
bbe37e4c	201	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
2c861d89	202	rc = 0;
63f1934d DJS	203	goto out_unlock;
	204	}
	205
bbe37e4c DJS	206	private = dev_get_drvdata(&sch->dev);
	207	if (private->state == VFIO_CCW_STATE_NOT_OPER) {
	208	private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
	209	VFIO_CCW_STATE_STANDBY;
	210	}
2c861d89	211	rc = 0;
bbe37e4c	212
63f1934d DJS	213	out_unlock:
	214	spin_unlock_irqrestore(sch->lock, flags);
	215
2c861d89	216	return rc;
63f1934d DJS	217	}
	218
	219	static struct css_device_id vfio_ccw_sch_ids[] = {
	220	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
	221	{ /* end of list */ },
	222	};
	223	MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
	224
	225	static struct css_driver vfio_ccw_sch_driver = {
	226	.drv = {
	227	.name = "vfio_ccw",
	228	.owner = THIS_MODULE,
	229	},
	230	.subchannel_type = vfio_ccw_sch_ids,
	231	.irq = vfio_ccw_sch_irq,
	232	.probe = vfio_ccw_sch_probe,
	233	.remove = vfio_ccw_sch_remove,
	234	.shutdown = vfio_ccw_sch_shutdown,
	235	.sch_event = vfio_ccw_sch_event,
	236	};
	237
	238	static int __init vfio_ccw_sch_init(void)
	239	{
	240	int ret;
	241
e5f84dba DJS	242	vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
	243	if (!vfio_ccw_work_q)
	244	return -ENOMEM;
	245
bf42daed EF	246	vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
	247	sizeof(struct ccw_io_region), 0,
	248	SLAB_ACCOUNT, 0,
	249	sizeof(struct ccw_io_region), NULL);
	250	if (!vfio_ccw_io_region) {
	251	destroy_workqueue(vfio_ccw_work_q);
	252	return -ENOMEM;
	253	}
	254
63f1934d DJS	255	isc_register(VFIO_CCW_ISC);
63f1934d DJS	256	ret = css_driver_register(&vfio_ccw_sch_driver);
e5f84dba	257	if (ret) {
63f1934d	258	isc_unregister(VFIO_CCW_ISC);
bf42daed	259	kmem_cache_destroy(vfio_ccw_io_region);
e5f84dba DJS	260	destroy_workqueue(vfio_ccw_work_q);
e5f84dba DJS	261	}
63f1934d DJS	262
	263	return ret;
	264	}
	265
	266	static void __exit vfio_ccw_sch_exit(void)
	267	{
	268	css_driver_unregister(&vfio_ccw_sch_driver);
	269	isc_unregister(VFIO_CCW_ISC);
bf42daed	270	kmem_cache_destroy(vfio_ccw_io_region);
e5f84dba	271	destroy_workqueue(vfio_ccw_work_q);
63f1934d DJS	272	}
	273	module_init(vfio_ccw_sch_init);
	274	module_exit(vfio_ccw_sch_exit);
	275
	276	MODULE_LICENSE("GPL v2");