| 1 | /* |
| 2 | * IOVA tree implementation based on GTree. |
| 3 | * |
| 4 | * Copyright 2018 Red Hat, Inc. |
| 5 | * |
| 6 | * Authors: |
| 7 | * Peter Xu <peterx@redhat.com> |
| 8 | * |
| 9 | * This work is licensed under the terms of the GNU GPL, version 2 or later. |
| 10 | */ |
| 11 | |
| 12 | #include "qemu/osdep.h" |
| 13 | #include "qemu/iova-tree.h" |
| 14 | |
| 15 | struct IOVATree { |
| 16 | GTree *tree; |
| 17 | }; |
| 18 | |
| 19 | /* Args to pass to iova_tree_alloc foreach function. */ |
| 20 | struct IOVATreeAllocArgs { |
| 21 | /* Size of the desired allocation */ |
| 22 | size_t new_size; |
| 23 | |
| 24 | /* The minimum address allowed in the allocation */ |
| 25 | hwaddr iova_begin; |
| 26 | |
| 27 | /* Map at the left of the hole, can be NULL if "this" is first one */ |
| 28 | const DMAMap *prev; |
| 29 | |
| 30 | /* Map at the right of the hole, can be NULL if "prev" is the last one */ |
| 31 | const DMAMap *this; |
| 32 | |
| 33 | /* If found, we fill in the IOVA here */ |
| 34 | hwaddr iova_result; |
| 35 | |
| 36 | /* Whether have we found a valid IOVA */ |
| 37 | bool iova_found; |
| 38 | }; |
| 39 | |
| 40 | typedef struct IOVATreeFindIOVAArgs { |
| 41 | const DMAMap *needle; |
| 42 | const DMAMap *result; |
| 43 | } IOVATreeFindIOVAArgs; |
| 44 | |
| 45 | /** |
| 46 | * Iterate args to the next hole |
| 47 | * |
| 48 | * @args: The alloc arguments |
| 49 | * @next: The next mapping in the tree. Can be NULL to signal the last one |
| 50 | */ |
| 51 | static void iova_tree_alloc_args_iterate(struct IOVATreeAllocArgs *args, |
| 52 | const DMAMap *next) |
| 53 | { |
| 54 | args->prev = args->this; |
| 55 | args->this = next; |
| 56 | } |
| 57 | |
| 58 | static int iova_tree_compare(gconstpointer a, gconstpointer b, gpointer data) |
| 59 | { |
| 60 | const DMAMap *m1 = a, *m2 = b; |
| 61 | |
| 62 | if (m1->iova > m2->iova + m2->size) { |
| 63 | return 1; |
| 64 | } |
| 65 | |
| 66 | if (m1->iova + m1->size < m2->iova) { |
| 67 | return -1; |
| 68 | } |
| 69 | |
| 70 | /* Overlapped */ |
| 71 | return 0; |
| 72 | } |
| 73 | |
| 74 | IOVATree *iova_tree_new(void) |
| 75 | { |
| 76 | IOVATree *iova_tree = g_new0(IOVATree, 1); |
| 77 | |
| 78 | /* We don't have values actually, no need to free */ |
| 79 | iova_tree->tree = g_tree_new_full(iova_tree_compare, NULL, g_free, NULL); |
| 80 | |
| 81 | return iova_tree; |
| 82 | } |
| 83 | |
| 84 | const DMAMap *iova_tree_find(const IOVATree *tree, const DMAMap *map) |
| 85 | { |
| 86 | return g_tree_lookup(tree->tree, map); |
| 87 | } |
| 88 | |
| 89 | static gboolean iova_tree_find_address_iterator(gpointer key, gpointer value, |
| 90 | gpointer data) |
| 91 | { |
| 92 | const DMAMap *map = key; |
| 93 | IOVATreeFindIOVAArgs *args = data; |
| 94 | const DMAMap *needle; |
| 95 | |
| 96 | g_assert(key == value); |
| 97 | |
| 98 | needle = args->needle; |
| 99 | if (map->translated_addr + map->size < needle->translated_addr || |
| 100 | needle->translated_addr + needle->size < map->translated_addr) { |
| 101 | return false; |
| 102 | } |
| 103 | |
| 104 | args->result = map; |
| 105 | return true; |
| 106 | } |
| 107 | |
| 108 | const DMAMap *iova_tree_find_iova(const IOVATree *tree, const DMAMap *map) |
| 109 | { |
| 110 | IOVATreeFindIOVAArgs args = { |
| 111 | .needle = map, |
| 112 | }; |
| 113 | |
| 114 | g_tree_foreach(tree->tree, iova_tree_find_address_iterator, &args); |
| 115 | return args.result; |
| 116 | } |
| 117 | |
| 118 | static inline void iova_tree_insert_internal(GTree *gtree, DMAMap *range) |
| 119 | { |
| 120 | /* Key and value are sharing the same range data */ |
| 121 | g_tree_insert(gtree, range, range); |
| 122 | } |
| 123 | |
| 124 | int iova_tree_insert(IOVATree *tree, const DMAMap *map) |
| 125 | { |
| 126 | DMAMap *new; |
| 127 | |
| 128 | if (map->iova + map->size < map->iova || map->perm == IOMMU_NONE) { |
| 129 | return IOVA_ERR_INVALID; |
| 130 | } |
| 131 | |
| 132 | /* We don't allow to insert range that overlaps with existings */ |
| 133 | if (iova_tree_find(tree, map)) { |
| 134 | return IOVA_ERR_OVERLAP; |
| 135 | } |
| 136 | |
| 137 | new = g_new0(DMAMap, 1); |
| 138 | memcpy(new, map, sizeof(*new)); |
| 139 | iova_tree_insert_internal(tree->tree, new); |
| 140 | |
| 141 | return IOVA_OK; |
| 142 | } |
| 143 | |
| 144 | void iova_tree_remove(IOVATree *tree, DMAMap map) |
| 145 | { |
| 146 | const DMAMap *overlap; |
| 147 | |
| 148 | while ((overlap = iova_tree_find(tree, &map))) { |
| 149 | g_tree_remove(tree->tree, overlap); |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | /** |
| 154 | * Try to find an unallocated IOVA range between prev and this elements. |
| 155 | * |
| 156 | * @args: Arguments to allocation |
| 157 | * |
| 158 | * Cases: |
| 159 | * |
| 160 | * (1) !prev, !this: No entries allocated, always succeed |
| 161 | * |
| 162 | * (2) !prev, this: We're iterating at the 1st element. |
| 163 | * |
| 164 | * (3) prev, !this: We're iterating at the last element. |
| 165 | * |
| 166 | * (4) prev, this: this is the most common case, we'll try to find a hole |
| 167 | * between "prev" and "this" mapping. |
| 168 | * |
| 169 | * Note that this function assumes the last valid iova is HWADDR_MAX, but it |
| 170 | * searches linearly so it's easy to discard the result if it's not the case. |
| 171 | */ |
| 172 | static void iova_tree_alloc_map_in_hole(struct IOVATreeAllocArgs *args) |
| 173 | { |
| 174 | const DMAMap *prev = args->prev, *this = args->this; |
| 175 | uint64_t hole_start, hole_last; |
| 176 | |
| 177 | if (this && this->iova + this->size < args->iova_begin) { |
| 178 | return; |
| 179 | } |
| 180 | |
| 181 | hole_start = MAX(prev ? prev->iova + prev->size + 1 : 0, args->iova_begin); |
| 182 | hole_last = this ? this->iova : HWADDR_MAX; |
| 183 | |
| 184 | if (hole_last - hole_start > args->new_size) { |
| 185 | args->iova_result = hole_start; |
| 186 | args->iova_found = true; |
| 187 | } |
| 188 | } |
| 189 | |
| 190 | /** |
| 191 | * Foreach dma node in the tree, compare if there is a hole with its previous |
| 192 | * node (or minimum iova address allowed) and the node. |
| 193 | * |
| 194 | * @key: Node iterating |
| 195 | * @value: Node iterating |
| 196 | * @pargs: Struct to communicate with the outside world |
| 197 | * |
| 198 | * Return: false to keep iterating, true if needs break. |
| 199 | */ |
| 200 | static gboolean iova_tree_alloc_traverse(gpointer key, gpointer value, |
| 201 | gpointer pargs) |
| 202 | { |
| 203 | struct IOVATreeAllocArgs *args = pargs; |
| 204 | DMAMap *node = value; |
| 205 | |
| 206 | assert(key == value); |
| 207 | |
| 208 | iova_tree_alloc_args_iterate(args, node); |
| 209 | iova_tree_alloc_map_in_hole(args); |
| 210 | return args->iova_found; |
| 211 | } |
| 212 | |
| 213 | int iova_tree_alloc_map(IOVATree *tree, DMAMap *map, hwaddr iova_begin, |
| 214 | hwaddr iova_last) |
| 215 | { |
| 216 | struct IOVATreeAllocArgs args = { |
| 217 | .new_size = map->size, |
| 218 | .iova_begin = iova_begin, |
| 219 | }; |
| 220 | |
| 221 | if (unlikely(iova_last < iova_begin)) { |
| 222 | return IOVA_ERR_INVALID; |
| 223 | } |
| 224 | |
| 225 | /* |
| 226 | * Find a valid hole for the mapping |
| 227 | * |
| 228 | * Assuming low iova_begin, so no need to do a binary search to |
| 229 | * locate the first node. |
| 230 | * |
| 231 | * TODO: Replace all this with g_tree_node_first/next/last when available |
| 232 | * (from glib since 2.68). To do it with g_tree_foreach complicates the |
| 233 | * code a lot. |
| 234 | * |
| 235 | */ |
| 236 | g_tree_foreach(tree->tree, iova_tree_alloc_traverse, &args); |
| 237 | if (!args.iova_found) { |
| 238 | /* |
| 239 | * Either tree is empty or the last hole is still not checked. |
| 240 | * g_tree_foreach does not compare (last, iova_last] range, so we check |
| 241 | * it here. |
| 242 | */ |
| 243 | iova_tree_alloc_args_iterate(&args, NULL); |
| 244 | iova_tree_alloc_map_in_hole(&args); |
| 245 | } |
| 246 | |
| 247 | if (!args.iova_found || args.iova_result + map->size > iova_last) { |
| 248 | return IOVA_ERR_NOMEM; |
| 249 | } |
| 250 | |
| 251 | map->iova = args.iova_result; |
| 252 | return iova_tree_insert(tree, map); |
| 253 | } |
| 254 | |
| 255 | void iova_tree_destroy(IOVATree *tree) |
| 256 | { |
| 257 | g_tree_destroy(tree->tree); |
| 258 | g_free(tree); |
| 259 | } |
| 260 | |
| 261 | static int gpa_tree_compare(gconstpointer a, gconstpointer b, gpointer data) |
| 262 | { |
| 263 | const DMAMap *m1 = a, *m2 = b; |
| 264 | |
| 265 | if (m1->translated_addr > m2->translated_addr + m2->size) { |
| 266 | return 1; |
| 267 | } |
| 268 | |
| 269 | if (m1->translated_addr + m1->size < m2->translated_addr) { |
| 270 | return -1; |
| 271 | } |
| 272 | |
| 273 | /* Overlapped */ |
| 274 | return 0; |
| 275 | } |
| 276 | |
| 277 | IOVATree *gpa_tree_new(void) |
| 278 | { |
| 279 | IOVATree *gpa_tree = g_new0(IOVATree, 1); |
| 280 | |
| 281 | gpa_tree->tree = g_tree_new_full(gpa_tree_compare, NULL, g_free, NULL); |
| 282 | |
| 283 | return gpa_tree; |
| 284 | } |
| 285 | |
| 286 | int gpa_tree_insert(IOVATree *tree, const DMAMap *map) |
| 287 | { |
| 288 | DMAMap *new; |
| 289 | |
| 290 | if (map->translated_addr + map->size < map->translated_addr || |
| 291 | map->perm == IOMMU_NONE) { |
| 292 | return IOVA_ERR_INVALID; |
| 293 | } |
| 294 | |
| 295 | /* We don't allow inserting ranges that overlap with existing ones */ |
| 296 | if (iova_tree_find(tree, map)) { |
| 297 | return IOVA_ERR_OVERLAP; |
| 298 | } |
| 299 | |
| 300 | new = g_new0(DMAMap, 1); |
| 301 | memcpy(new, map, sizeof(*new)); |
| 302 | iova_tree_insert_internal(tree->tree, new); |
| 303 | |
| 304 | return IOVA_OK; |
| 305 | } |