summaryrefslogtreecommitdiffstats
path: root/drivers/s390/cio/vfio_ccw_fsm.c
blob: 797a82731159a5f9f584810f924adc3467b1e702 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
// SPDX-License-Identifier: GPL-2.0
/*
 * Finite state machine for vfio-ccw device handling
 *
 * Copyright IBM Corp. 2017
 *
 * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
 */

#include <linux/vfio.h>
#include <linux/mdev.h>

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

#define CREATE_TRACE_POINTS
#include "vfio_ccw_trace.h"

static int fsm_io_helper(struct vfio_ccw_private *private)
{
	struct subchannel *sch;
	union orb *orb;
	int ccode;
	__u8 lpm;
	unsigned long flags;
	int ret;

	sch = private->sch;

	spin_lock_irqsave(sch->lock, flags);
	private->state = VFIO_CCW_STATE_BUSY;

	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;
		ret = 0;
		break;
	case 1:		/* Status pending */
	case 2:		/* Busy */
		ret = -EBUSY;
		break;
	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))
			ret = -ENODEV;
		else
			ret = sch->lpm ? -EACCES : -ENODEV;
		break;
	}
	default:
		ret = ccode;
	}
	spin_unlock_irqrestore(sch->lock, flags);
	return ret;
}

static void fsm_notoper(struct vfio_ccw_private *private,
			enum vfio_ccw_event event)
{
	struct subchannel *sch = private->sch;

	/*
	 * TODO:
	 * Probably we should send the machine check to the guest.
	 */
	css_sched_sch_todo(sch, SCH_TODO_UNREG);
	private->state = VFIO_CCW_STATE_NOT_OPER;
}

/*
 * No operation action.
 */
static void fsm_nop(struct vfio_ccw_private *private,
		    enum vfio_ccw_event event)
{
}

static void fsm_io_error(struct vfio_ccw_private *private,
			 enum vfio_ccw_event event)
{
	pr_err("vfio-ccw: FSM: I/O request from state:%d\n", private->state);
	private->io_region.ret_code = -EIO;
}

static void fsm_io_busy(struct vfio_ccw_private *private,
			enum vfio_ccw_event event)
{
	private->io_region.ret_code = -EBUSY;
}

static void fsm_disabled_irq(struct vfio_ccw_private *private,
			     enum vfio_ccw_event event)
{
	struct subchannel *sch = private->sch;

	/*
	 * An interrupt in a disabled state means a previous disable was not
	 * successful - should not happen, but we try to disable again.
	 */
	cio_disable_subchannel(sch);
}
inline struct subchannel_id get_schid(struct vfio_ccw_private *p)
{
	return p->sch->schid;
}

/*
 * Deal with the ccw command request from the userspace.
 */
static void fsm_io_request(struct vfio_ccw_private *private,
			   enum vfio_ccw_event event)
{
	union orb *orb;
	union scsw *scsw = &private->scsw;
	struct ccw_io_region *io_region = &private->io_region;
	struct mdev_device *mdev = private->mdev;
	char *errstr = "request";

	private->state = VFIO_CCW_STATE_BOXED;

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

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

		/* Don't try to build a cp if transport mode is specified. */
		if (orb->tm.b) {
			io_region->ret_code = -EOPNOTSUPP;
			errstr = "transport mode";
			goto err_out;
		}
		io_region->ret_code = cp_init(&private->cp, mdev_dev(mdev),
					      orb);
		if (io_region->ret_code) {
			errstr = "cp init";
			goto err_out;
		}

		io_region->ret_code = cp_prefetch(&private->cp);
		if (io_region->ret_code) {
			errstr = "cp prefetch";
			cp_free(&private->cp);
			goto err_out;
		}

		/* Start channel program and wait for I/O interrupt. */
		io_region->ret_code = fsm_io_helper(private);
		if (io_region->ret_code) {
			errstr = "cp fsm_io_helper";
			cp_free(&private->cp);
			goto err_out;
		}
		return;
	} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
		/* XXX: Handle halt. */
		io_region->ret_code = -EOPNOTSUPP;
		goto err_out;
	} else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
		/* XXX: Handle clear. */
		io_region->ret_code = -EOPNOTSUPP;
		goto err_out;
	}

err_out:
	private->state = VFIO_CCW_STATE_IDLE;
	trace_vfio_ccw_io_fctl(scsw->cmd.fctl, get_schid(private),
			       io_region->ret_code, errstr);
}

/*
 * Got an interrupt for a normal io (state busy).
 */
static void fsm_irq(struct vfio_ccw_private *private,
		    enum vfio_ccw_event event)
{
	struct irb *irb = this_cpu_ptr(&cio_irb);

	memcpy(&private->irb, irb, sizeof(*irb));

	queue_work(vfio_ccw_work_q, &private->io_work);

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

/*
 * Device statemachine
 */
fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
	[VFIO_CCW_STATE_NOT_OPER] = {
		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_nop,
		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_error,
		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_disabled_irq,
	},
	[VFIO_CCW_STATE_STANDBY] = {
		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_error,
		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
	},
	[VFIO_CCW_STATE_IDLE] = {
		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_request,
		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
	},
	[VFIO_CCW_STATE_BOXED] = {
		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_busy,
		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
	},
	[VFIO_CCW_STATE_BUSY] = {
		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_busy,
		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
	},
};