drivers/vhost/iotlb.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (C) 2020 Red Hat, Inc.
   3  * Author: Jason Wang <jasowang@redhat.com>
   4  *
   5  * IOTLB implementation for vhost.
   6  */
   7 #include <linux/slab.h>
   8 #include <linux/vhost_iotlb.h>
   9 #include <linux/module.h>
  10
  11 #define MOD_VERSION  "0.1"
  12 #define MOD_DESC     "VHOST IOTLB"
  13 #define MOD_AUTHOR   "Jason Wang <jasowang@redhat.com>"
  14 #define MOD_LICENSE  "GPL v2"
  15
  16 #define START(map) ((map)->start)
  17 #define LAST(map) ((map)->last)
  18
  19 INTERVAL_TREE_DEFINE(struct vhost_iotlb_map,
  20                      rb, __u64, __subtree_last,
  21                      START, LAST, static inline, vhost_iotlb_itree);
  22
  23 /**
  24  * vhost_iotlb_map_free - remove a map node and free it
  25  * @iotlb: the IOTLB
  26  * @map: the map that want to be remove and freed
  27  */
  28 void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
  29                           struct vhost_iotlb_map *map)
  30 {
  31         vhost_iotlb_itree_remove(map, &iotlb->root);
  32         list_del(&map->link);
  33         kfree(map);
  34         iotlb->nmaps--;
  35 }
  36 EXPORT_SYMBOL_GPL(vhost_iotlb_map_free);
  37
  38 /**
  39  * vhost_iotlb_add_range - add a new range to vhost IOTLB
  40  * @iotlb: the IOTLB
  41  * @start: start of the IOVA range
  42  * @last: last of IOVA range
  43  * @addr: the address that is mapped to @start
  44  * @perm: access permission of this range
  45  *
  46  * Returns an error last is smaller than start or memory allocation
  47  * fails
  48  */
  49 int vhost_iotlb_add_range(struct vhost_iotlb *iotlb,
  50                           u64 start, u64 last,
  51                           u64 addr, unsigned int perm)
  52 {
  53         struct vhost_iotlb_map *map;
  54
  55         if (last < start)
  56                 return -EFAULT;
  57
  58         if (iotlb->limit &&
  59             iotlb->nmaps == iotlb->limit &&
  60             iotlb->flags & VHOST_IOTLB_FLAG_RETIRE) {
  61                 map = list_first_entry(&iotlb->list, typeof(*map), link);
  62                 vhost_iotlb_map_free(iotlb, map);
  63         }
  64
  65         map = kmalloc(sizeof(*map), GFP_ATOMIC);
  66         if (!map)
  67                 return -ENOMEM;
  68
  69         map->start = start;
  70         map->size = last - start + 1;
  71         map->last = last;
  72         map->addr = addr;
  73         map->perm = perm;
  74
  75         iotlb->nmaps++;
  76         vhost_iotlb_itree_insert(map, &iotlb->root);
  77
  78         INIT_LIST_HEAD(&map->link);
  79         list_add_tail(&map->link, &iotlb->list);
  80
  81         return 0;
  82 }
  83 EXPORT_SYMBOL_GPL(vhost_iotlb_add_range);
  84
  85 /**
  86  * vring_iotlb_del_range - delete overlapped ranges from vhost IOTLB
  87  * @iotlb: the IOTLB
  88  * @start: start of the IOVA range
  89  * @last: last of IOVA range
  90  */
  91 void vhost_iotlb_del_range(struct vhost_iotlb *iotlb, u64 start, u64 last)
  92 {
  93         struct vhost_iotlb_map *map;
  94
  95         while ((map = vhost_iotlb_itree_iter_first(&iotlb->root,
  96                                                    start, last)))
  97                 vhost_iotlb_map_free(iotlb, map);
  98 }
  99 EXPORT_SYMBOL_GPL(vhost_iotlb_del_range);
 100
 101 /**
 102  * vhost_iotlb_alloc - add a new vhost IOTLB
 103  * @limit: maximum number of IOTLB entries
 104  * @flags: VHOST_IOTLB_FLAG_XXX
 105  *
 106  * Returns an error is memory allocation fails
 107  */
 108 struct vhost_iotlb *vhost_iotlb_alloc(unsigned int limit, unsigned int flags)
 109 {
 110         struct vhost_iotlb *iotlb = kzalloc(sizeof(*iotlb), GFP_KERNEL);
 111
 112         if (!iotlb)
 113                 return NULL;
 114
 115         iotlb->root = RB_ROOT_CACHED;
 116         iotlb->limit = limit;
 117         iotlb->nmaps = 0;
 118         iotlb->flags = flags;
 119         INIT_LIST_HEAD(&iotlb->list);
 120
 121         return iotlb;
 122 }
 123 EXPORT_SYMBOL_GPL(vhost_iotlb_alloc);
 124
 125 /**
 126  * vhost_iotlb_reset - reset vhost IOTLB (free all IOTLB entries)
 127  * @iotlb: the IOTLB to be reset
 128  */
 129 void vhost_iotlb_reset(struct vhost_iotlb *iotlb)
 130 {
 131         vhost_iotlb_del_range(iotlb, 0ULL, 0ULL - 1);
 132 }
 133 EXPORT_SYMBOL_GPL(vhost_iotlb_reset);
 134
 135 /**
 136  * vhost_iotlb_free - reset and free vhost IOTLB
 137  * @iotlb: the IOTLB to be freed
 138  */
 139 void vhost_iotlb_free(struct vhost_iotlb *iotlb)
 140 {
 141         if (iotlb) {
 142                 vhost_iotlb_reset(iotlb);
 143                 kfree(iotlb);
 144         }
 145 }
 146 EXPORT_SYMBOL_GPL(vhost_iotlb_free);
 147
 148 /**
 149  * vhost_iotlb_itree_first - return the first overlapped range
 150  * @iotlb: the IOTLB
 151  * @start: start of IOVA range
 152  * @last: last byte in IOVA range
 153  */
 154 struct vhost_iotlb_map *
 155 vhost_iotlb_itree_first(struct vhost_iotlb *iotlb, u64 start, u64 last)
 156 {
 157         return vhost_iotlb_itree_iter_first(&iotlb->root, start, last);
 158 }
 159 EXPORT_SYMBOL_GPL(vhost_iotlb_itree_first);
 160
 161 /**
 162  * vhost_iotlb_itree_next - return the next overlapped range
 163  * @map: the starting map node
 164  * @start: start of IOVA range
 165  * @last: last byte IOVA range
 166  */
 167 struct vhost_iotlb_map *
 168 vhost_iotlb_itree_next(struct vhost_iotlb_map *map, u64 start, u64 last)
 169 {
 170         return vhost_iotlb_itree_iter_next(map, start, last);
 171 }
 172 EXPORT_SYMBOL_GPL(vhost_iotlb_itree_next);
 173
 174 MODULE_VERSION(MOD_VERSION);
 175 MODULE_DESCRIPTION(MOD_DESC);
 176 MODULE_AUTHOR(MOD_AUTHOR);
 177 MODULE_LICENSE(MOD_LICENSE);