vfio_ccw_chp.c

  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}