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(buf, (void *)region + pos, count))
29		ret = -EFAULT;
30	else
31		ret = count;
32	mutex_unlock(&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(&private->io_mutex))
49		return -EAGAIN;
50
51	region = private->region[i].data;
52	if (copy_from_user((void *)region + pos, buf, count)) {
53		ret = -EFAULT;
54		goto out_unlock;
55	}
56
57	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_ASYNC_REQ);
58
59	ret = region->ret_code ? region->ret_code : count;
60
61out_unlock:
62	mutex_unlock(&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					    &vfio_ccw_async_region_ops,
83					    sizeof(struct ccw_cmd_region),
84					    VFIO_REGION_INFO_FLAG_READ |
85					    VFIO_REGION_INFO_FLAG_WRITE,
86					    private->cmd_region);
87}
88