xref: /openbmc/linux/drivers/s390/cio/vfio_ccw_chp.c (revision 008a011d)
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 
vfio_ccw_schib_region_read(struct vfio_ccw_private * private,char __user * buf,size_t count,loff_t * ppos)15 static 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 
45 out:
46 	mutex_unlock(&private->io_mutex);
47 	return ret;
48 }
49 
vfio_ccw_schib_region_write(struct vfio_ccw_private * private,const char __user * buf,size_t count,loff_t * ppos)50 static 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 
vfio_ccw_schib_region_release(struct vfio_ccw_private * private,struct vfio_ccw_region * region)58 static void vfio_ccw_schib_region_release(struct vfio_ccw_private *private,
59 					  struct vfio_ccw_region *region)
60 {
61 
62 }
63 
64 static 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 
vfio_ccw_register_schib_dev_regions(struct vfio_ccw_private * private)70 int 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 
vfio_ccw_crw_region_read(struct vfio_ccw_private * private,char __user * buf,size_t count,loff_t * ppos)80 static 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, 1);
119 
120 	return ret;
121 }
122 
vfio_ccw_crw_region_write(struct vfio_ccw_private * private,const char __user * buf,size_t count,loff_t * ppos)123 static 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 
vfio_ccw_crw_region_release(struct vfio_ccw_private * private,struct vfio_ccw_region * region)130 static void vfio_ccw_crw_region_release(struct vfio_ccw_private *private,
131 					struct vfio_ccw_region *region)
132 {
133 
134 }
135 
136 static 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 
vfio_ccw_register_crw_dev_regions(struct vfio_ccw_private * private)142 int 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