1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Async I/O region for vfio_ccw
4 *
5 * Copyright Red Hat, Inc. 2019
6 *
7 * Author(s): Cornelia Huck <cohuck@redhat.com>
8 */
9
10#include <linux/vfio.h>
11
12#include "vfio_ccw_private.h"
13
14static ssize_t vfio_ccw_async_region_read(struct vfio_ccw_private *private,
15 char __user *buf, size_t count,
16 loff_t *ppos)
17{
18 unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
19 loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
20 struct ccw_cmd_region *region;
21 int ret;
22
23 if (pos + count > sizeof(*region))
24 return -EINVAL;
25
26 mutex_lock(&private->io_mutex);
27 region = private->region[i].data;
28 if (copy_to_user(to: buf, from: (void *)region + pos, n: count))
29 ret = -EFAULT;
30 else
31 ret = count;
32 mutex_unlock(lock: &private->io_mutex);
33 return ret;
34}
35
36static ssize_t vfio_ccw_async_region_write(struct vfio_ccw_private *private,
37 const char __user *buf, size_t count,
38 loff_t *ppos)
39{
40 unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
41 loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
42 struct ccw_cmd_region *region;
43 int ret;
44
45 if (pos + count > sizeof(*region))
46 return -EINVAL;
47
48 if (!mutex_trylock(lock: &private->io_mutex))
49 return -EAGAIN;
50
51 region = private->region[i].data;
52 if (copy_from_user(to: (void *)region + pos, from: buf, n: count)) {
53 ret = -EFAULT;
54 goto out_unlock;
55 }
56
57 vfio_ccw_fsm_event(private, event: VFIO_CCW_EVENT_ASYNC_REQ);
58
59 ret = region->ret_code ? region->ret_code : count;
60
61out_unlock:
62 mutex_unlock(lock: &private->io_mutex);
63 return ret;
64}
65
66static void vfio_ccw_async_region_release(struct vfio_ccw_private *private,
67 struct vfio_ccw_region *region)
68{
69
70}
71
72static const struct vfio_ccw_regops vfio_ccw_async_region_ops = {
73 .read = vfio_ccw_async_region_read,
74 .write = vfio_ccw_async_region_write,
75 .release = vfio_ccw_async_region_release,
76};
77
78int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private)
79{
80 return vfio_ccw_register_dev_region(private,
81 VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD,
82 ops: &vfio_ccw_async_region_ops,
83 size: sizeof(struct ccw_cmd_region),
84 VFIO_REGION_INFO_FLAG_READ |
85 VFIO_REGION_INFO_FLAG_WRITE,
86 data: private->cmd_region);
87}
88

source code of linux/drivers/s390/cio/vfio_ccw_async.c