drivers/s390/cio/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
  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         unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
  20         loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
  21         struct ccw_schib_region *region;
  22         int ret;
  23
  24         if (pos + count > sizeof(*region))
  25                 return -EINVAL;
  26
  27         mutex_lock(&private->io_mutex);
  28         region = private->region[i].data;
  29
  30         if (cio_update_schib(private->sch)) {
  31                 ret = -ENODEV;
  32                 goto out;
  33         }
  34
  35         memcpy(region, &private->sch->schib, sizeof(*region));
  36
  37         if (copy_to_user(buf, (void *)region + pos, count)) {
  38                 ret = -EFAULT;
  39                 goto out;
  40         }
  41
  42         ret = count;
  43
  44 out:
  45         mutex_unlock(&private->io_mutex);
  46         return ret;
  47 }
  48
  49 static ssize_t vfio_ccw_schib_region_write(struct vfio_ccw_private *private,
  50                                            const char __user *buf, size_t count,
  51                                            loff_t *ppos)
  52 {
  53         return -EINVAL;
  54 }
  55
  56
  57 static void vfio_ccw_schib_region_release(struct vfio_ccw_private *private,
  58                                           struct vfio_ccw_region *region)
  59 {
  60
  61 }
  62
  63 static const struct vfio_ccw_regops vfio_ccw_schib_region_ops = {
  64         .read = vfio_ccw_schib_region_read,
  65         .write = vfio_ccw_schib_region_write,
  66         .release = vfio_ccw_schib_region_release,
  67 };
  68
  69 int vfio_ccw_register_schib_dev_regions(struct vfio_ccw_private *private)
  70 {
  71         return vfio_ccw_register_dev_region(private,
  72                                             VFIO_REGION_SUBTYPE_CCW_SCHIB,
  73                                             &vfio_ccw_schib_region_ops,
  74                                             sizeof(struct ccw_schib_region),
  75                                             VFIO_REGION_INFO_FLAG_READ,
  76                                             private->schib_region);
  77 }
  78
  79 static ssize_t vfio_ccw_crw_region_read(struct vfio_ccw_private *private,
  80                                         char __user *buf, size_t count,
  81                                         loff_t *ppos)
  82 {
  83         unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
  84         loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
  85         struct ccw_crw_region *region;
  86         struct vfio_ccw_crw *crw;
  87         int ret;
  88
  89         if (pos + count > sizeof(*region))
  90                 return -EINVAL;
  91
  92         crw = list_first_entry_or_null(&private->crw,
  93                                        struct vfio_ccw_crw, next);
  94
  95         if (crw)
  96                 list_del(&crw->next);
  97
  98         mutex_lock(&private->io_mutex);
  99         region = private->region[i].data;
 100
 101         if (crw)
 102                 memcpy(&region->crw, &crw->crw, sizeof(region->crw));
 103
 104         if (copy_to_user(buf, (void *)region + pos, count))
 105                 ret = -EFAULT;
 106         else
 107                 ret = count;
 108
 109         region->crw = 0;
 110
 111         mutex_unlock(&private->io_mutex);
 112
 113         kfree(crw);
 114
 115         /* Notify the guest if more CRWs are on our queue */
 116         if (!list_empty(&private->crw) && private->crw_trigger)
 117                 eventfd_signal(private->crw_trigger, 1);
 118
 119         return ret;
 120 }
 121
 122 static ssize_t vfio_ccw_crw_region_write(struct vfio_ccw_private *private,
 123                                          const char __user *buf, size_t count,
 124                                          loff_t *ppos)
 125 {
 126         return -EINVAL;
 127 }
 128
 129 static void vfio_ccw_crw_region_release(struct vfio_ccw_private *private,
 130                                         struct vfio_ccw_region *region)
 131 {
 132
 133 }
 134
 135 static const struct vfio_ccw_regops vfio_ccw_crw_region_ops = {
 136         .read = vfio_ccw_crw_region_read,
 137         .write = vfio_ccw_crw_region_write,
 138         .release = vfio_ccw_crw_region_release,
 139 };
 140
 141 int vfio_ccw_register_crw_dev_regions(struct vfio_ccw_private *private)
 142 {
 143         return vfio_ccw_register_dev_region(private,
 144                                             VFIO_REGION_SUBTYPE_CCW_CRW,
 145                                             &vfio_ccw_crw_region_ops,
 146                                             sizeof(struct ccw_crw_region),
 147                                             VFIO_REGION_INFO_FLAG_READ,
 148                                             private->crw_region);
 149 }