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_ctx - 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  * @opaque: the opaque pointer for the new mapping
  46  *
  47  * Returns an error last is smaller than start or memory allocation
  48  * fails
  49  */
  50 int vhost_iotlb_add_range_ctx(struct vhost_iotlb *iotlb,
  51                               u64 start, u64 last,
  52                               u64 addr, unsigned int perm,
  53                               void *opaque)
  54 {
  55         struct vhost_iotlb_map *map;
  56
  57         if (last < start)
  58                 return -EFAULT;
  59
  60         if (iotlb->limit &&
  61             iotlb->nmaps == iotlb->limit &&
  62             iotlb->flags & VHOST_IOTLB_FLAG_RETIRE) {
  63                 map = list_first_entry(&iotlb->list, typeof(*map), link);
  64                 vhost_iotlb_map_free(iotlb, map);
  65         }
  66
  67         map = kmalloc(sizeof(*map), GFP_ATOMIC);
  68         if (!map)
  69                 return -ENOMEM;
  70
  71         map->start = start;
  72         map->size = last - start + 1;
  73         map->last = last;
  74         map->addr = addr;
  75         map->perm = perm;
  76         map->opaque = opaque;
  77
  78         iotlb->nmaps++;
  79         vhost_iotlb_itree_insert(map, &iotlb->root);
  80
  81         INIT_LIST_HEAD(&map->link);
  82         list_add_tail(&map->link, &iotlb->list);
  83
  84         return 0;
  85 }
  86 EXPORT_SYMBOL_GPL(vhost_iotlb_add_range_ctx);
  87
  88 int vhost_iotlb_add_range(struct vhost_iotlb *iotlb,
  89                           u64 start, u64 last,
  90                           u64 addr, unsigned int perm)
  91 {
  92         return vhost_iotlb_add_range_ctx(iotlb, start, last,
  93                                          addr, perm, NULL);
  94 }
  95 EXPORT_SYMBOL_GPL(vhost_iotlb_add_range);
  96
  97 /**
  98  * vhost_iotlb_del_range - delete overlapped ranges from vhost IOTLB
  99  * @iotlb: the IOTLB
 100  * @start: start of the IOVA range
 101  * @last: last of IOVA range
 102  */
 103 void vhost_iotlb_del_range(struct vhost_iotlb *iotlb, u64 start, u64 last)
 104 {
 105         struct vhost_iotlb_map *map;
 106
 107         while ((map = vhost_iotlb_itree_iter_first(&iotlb->root,
 108                                                    start, last)))
 109                 vhost_iotlb_map_free(iotlb, map);
 110 }
 111 EXPORT_SYMBOL_GPL(vhost_iotlb_del_range);
 112
 113 /**
 114  * vhost_iotlb_alloc - add a new vhost IOTLB
 115  * @limit: maximum number of IOTLB entries
 116  * @flags: VHOST_IOTLB_FLAG_XXX
 117  *
 118  * Returns an error is memory allocation fails
 119  */
 120 struct vhost_iotlb *vhost_iotlb_alloc(unsigned int limit, unsigned int flags)
 121 {
 122         struct vhost_iotlb *iotlb = kzalloc(sizeof(*iotlb), GFP_KERNEL);
 123
 124         if (!iotlb)
 125                 return NULL;
 126
 127         iotlb->root = RB_ROOT_CACHED;
 128         iotlb->limit = limit;
 129         iotlb->nmaps = 0;
 130         iotlb->flags = flags;
 131         INIT_LIST_HEAD(&iotlb->list);
 132
 133         return iotlb;
 134 }
 135 EXPORT_SYMBOL_GPL(vhost_iotlb_alloc);
 136
 137 /**
 138  * vhost_iotlb_reset - reset vhost IOTLB (free all IOTLB entries)
 139  * @iotlb: the IOTLB to be reset
 140  */
 141 void vhost_iotlb_reset(struct vhost_iotlb *iotlb)
 142 {
 143         vhost_iotlb_del_range(iotlb, 0ULL, 0ULL - 1);
 144 }
 145 EXPORT_SYMBOL_GPL(vhost_iotlb_reset);
 146
 147 /**
 148  * vhost_iotlb_free - reset and free vhost IOTLB
 149  * @iotlb: the IOTLB to be freed
 150  */
 151 void vhost_iotlb_free(struct vhost_iotlb *iotlb)
 152 {
 153         if (iotlb) {
 154                 vhost_iotlb_reset(iotlb);
 155                 kfree(iotlb);
 156         }
 157 }
 158 EXPORT_SYMBOL_GPL(vhost_iotlb_free);
 159
 160 /**
 161  * vhost_iotlb_itree_first - return the first overlapped range
 162  * @iotlb: the IOTLB
 163  * @start: start of IOVA range
 164  * @last: last byte in IOVA range
 165  */
 166 struct vhost_iotlb_map *
 167 vhost_iotlb_itree_first(struct vhost_iotlb *iotlb, u64 start, u64 last)
 168 {
 169         return vhost_iotlb_itree_iter_first(&iotlb->root, start, last);
 170 }
 171 EXPORT_SYMBOL_GPL(vhost_iotlb_itree_first);
 172
 173 /**
 174  * vhost_iotlb_itree_next - return the next overlapped range
 175  * @map: the starting map node
 176  * @start: start of IOVA range
 177  * @last: last byte IOVA range
 178  */
 179 struct vhost_iotlb_map *
 180 vhost_iotlb_itree_next(struct vhost_iotlb_map *map, u64 start, u64 last)
 181 {
 182         return vhost_iotlb_itree_iter_next(map, start, last);
 183 }
 184 EXPORT_SYMBOL_GPL(vhost_iotlb_itree_next);
 185
 186 MODULE_VERSION(MOD_VERSION);
 187 MODULE_DESCRIPTION(MOD_DESC);
 188 MODULE_AUTHOR(MOD_AUTHOR);
 189 MODULE_LICENSE(MOD_LICENSE);