1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Channel path related status regions for vfio_ccw
4 *
5 * Copyright IBM Corp. 2020
6 *
7 * Author(s): Farhan Ali <alifm@linux.ibm.com>
8 *            Eric Farman <farman@linux.ibm.com>
9 */
10
11#include <linux/slab.h>
12#include <linux/vfio.h>
13#include "vfio_ccw_private.h"
14
15static ssize_t vfio_ccw_schib_region_read(struct vfio_ccw_private *private,
16					  char __user *buf, size_t count,
17					  loff_t *ppos)
18{
19	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
20	unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
21	loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
22	struct ccw_schib_region *region;
23	int ret;
24
25	if (pos + count > sizeof(*region))
26		return -EINVAL;
27
28	mutex_lock(&private->io_mutex);
29	region = private->region[i].data;
30
31	if (cio_update_schib(sch)) {
32		ret = -ENODEV;
33		goto out;
34	}
35
36	memcpy(region, &sch->schib, sizeof(*region));
37
38	if (copy_to_user(buf, (void *)region + pos, count)) {
39		ret = -EFAULT;
40		goto out;
41	}
42
43	ret = count;
44
45out:
46	mutex_unlock(&private->io_mutex);
47	return ret;
48}
49
50static ssize_t vfio_ccw_schib_region_write(struct vfio_ccw_private *private,
51					   const char __user *buf, size_t count,
52					   loff_t *ppos)
53{
54	return -EINVAL;
55}
56
57
58static void vfio_ccw_schib_region_release(struct vfio_ccw_private *private,
59					  struct vfio_ccw_region *region)
60{
61
62}
63
64static const struct vfio_ccw_regops vfio_ccw_schib_region_ops = {
65	.read = vfio_ccw_schib_region_read,
66	.write = vfio_ccw_schib_region_write,
67	.release = vfio_ccw_schib_region_release,
68};
69
70int vfio_ccw_register_schib_dev_regions(struct vfio_ccw_private *private)
71{
72	return vfio_ccw_register_dev_region(private,
73					    VFIO_REGION_SUBTYPE_CCW_SCHIB,
74					    &vfio_ccw_schib_region_ops,
75					    sizeof(struct ccw_schib_region),
76					    VFIO_REGION_INFO_FLAG_READ,
77					    private->schib_region);
78}
79
80static ssize_t vfio_ccw_crw_region_read(struct vfio_ccw_private *private,
81					char __user *buf, size_t count,
82					loff_t *ppos)
83{
84	unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
85	loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
86	struct ccw_crw_region *region;
87	struct vfio_ccw_crw *crw;
88	int ret;
89
90	if (pos + count > sizeof(*region))
91		return -EINVAL;
92
93	crw = list_first_entry_or_null(&private->crw,
94				       struct vfio_ccw_crw, next);
95
96	if (crw)
97		list_del(&crw->next);
98
99	mutex_lock(&private->io_mutex);
100	region = private->region[i].data;
101
102	if (crw)
103		memcpy(&region->crw, &crw->crw, sizeof(region->crw));
104
105	if (copy_to_user(buf, (void *)region + pos, count))
106		ret = -EFAULT;
107	else
108		ret = count;
109
110	region->crw = 0;
111
112	mutex_unlock(&private->io_mutex);
113
114	kfree(crw);
115
116	/* Notify the guest if more CRWs are on our queue */
117	if (!list_empty(&private->crw) && private->crw_trigger)
118		eventfd_signal(private->crw_trigger);
119
120	return ret;
121}
122
123static ssize_t vfio_ccw_crw_region_write(struct vfio_ccw_private *private,
124					 const char __user *buf, size_t count,
125					 loff_t *ppos)
126{
127	return -EINVAL;
128}
129
130static void vfio_ccw_crw_region_release(struct vfio_ccw_private *private,
131					struct vfio_ccw_region *region)
132{
133
134}
135
136static const struct vfio_ccw_regops vfio_ccw_crw_region_ops = {
137	.read = vfio_ccw_crw_region_read,
138	.write = vfio_ccw_crw_region_write,
139	.release = vfio_ccw_crw_region_release,
140};
141
142int vfio_ccw_register_crw_dev_regions(struct vfio_ccw_private *private)
143{
144	return vfio_ccw_register_dev_region(private,
145					    VFIO_REGION_SUBTYPE_CCW_CRW,
146					    &vfio_ccw_crw_region_ops,
147					    sizeof(struct ccw_crw_region),
148					    VFIO_REGION_INFO_FLAG_READ,
149					    private->crw_region);
150}
151