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eecf5eed PX |
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 | ||
c5f1d0c4 | 12 | #include "qemu/osdep.h" |
eecf5eed PX |
13 | #include "qemu/iova-tree.h" |
14 | ||
15 | struct IOVATree { | |
16 | GTree *tree; | |
17 | }; | |
18 | ||
9376bde8 EP |
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 | ||
193d17be EP |
40 | typedef struct IOVATreeFindIOVAArgs { |
41 | const DMAMap *needle; | |
42 | const DMAMap *result; | |
43 | } IOVATreeFindIOVAArgs; | |
44 | ||
9376bde8 EP |
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 | ||
eecf5eed PX |
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 | ||
a89b34be | 84 | const DMAMap *iova_tree_find(const IOVATree *tree, const DMAMap *map) |
eecf5eed PX |
85 | { |
86 | return g_tree_lookup(tree->tree, map); | |
87 | } | |
88 | ||
193d17be EP |
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 | ||
a89b34be | 118 | const DMAMap *iova_tree_find_address(const IOVATree *tree, hwaddr iova) |
eecf5eed | 119 | { |
a89b34be | 120 | const DMAMap map = { .iova = iova, .size = 0 }; |
eecf5eed PX |
121 | |
122 | return iova_tree_find(tree, &map); | |
123 | } | |
124 | ||
125 | static inline void iova_tree_insert_internal(GTree *gtree, DMAMap *range) | |
126 | { | |
127 | /* Key and value are sharing the same range data */ | |
128 | g_tree_insert(gtree, range, range); | |
129 | } | |
130 | ||
a89b34be | 131 | int iova_tree_insert(IOVATree *tree, const DMAMap *map) |
eecf5eed PX |
132 | { |
133 | DMAMap *new; | |
134 | ||
135 | if (map->iova + map->size < map->iova || map->perm == IOMMU_NONE) { | |
136 | return IOVA_ERR_INVALID; | |
137 | } | |
138 | ||
139 | /* We don't allow to insert range that overlaps with existings */ | |
140 | if (iova_tree_find(tree, map)) { | |
141 | return IOVA_ERR_OVERLAP; | |
142 | } | |
143 | ||
144 | new = g_new0(DMAMap, 1); | |
145 | memcpy(new, map, sizeof(*new)); | |
146 | iova_tree_insert_internal(tree->tree, new); | |
147 | ||
148 | return IOVA_OK; | |
149 | } | |
150 | ||
151 | static gboolean iova_tree_traverse(gpointer key, gpointer value, | |
152 | gpointer data) | |
153 | { | |
154 | iova_tree_iterator iterator = data; | |
155 | DMAMap *map = key; | |
156 | ||
157 | g_assert(key == value); | |
158 | ||
159 | return iterator(map); | |
160 | } | |
161 | ||
162 | void iova_tree_foreach(IOVATree *tree, iova_tree_iterator iterator) | |
163 | { | |
164 | g_tree_foreach(tree->tree, iova_tree_traverse, iterator); | |
165 | } | |
166 | ||
a89b34be | 167 | int iova_tree_remove(IOVATree *tree, const DMAMap *map) |
eecf5eed | 168 | { |
a89b34be | 169 | const DMAMap *overlap; |
eecf5eed PX |
170 | |
171 | while ((overlap = iova_tree_find(tree, map))) { | |
172 | g_tree_remove(tree->tree, overlap); | |
173 | } | |
174 | ||
175 | return IOVA_OK; | |
176 | } | |
177 | ||
9376bde8 EP |
178 | /** |
179 | * Try to find an unallocated IOVA range between prev and this elements. | |
180 | * | |
181 | * @args: Arguments to allocation | |
182 | * | |
183 | * Cases: | |
184 | * | |
185 | * (1) !prev, !this: No entries allocated, always succeed | |
186 | * | |
187 | * (2) !prev, this: We're iterating at the 1st element. | |
188 | * | |
189 | * (3) prev, !this: We're iterating at the last element. | |
190 | * | |
191 | * (4) prev, this: this is the most common case, we'll try to find a hole | |
192 | * between "prev" and "this" mapping. | |
193 | * | |
194 | * Note that this function assumes the last valid iova is HWADDR_MAX, but it | |
195 | * searches linearly so it's easy to discard the result if it's not the case. | |
196 | */ | |
197 | static void iova_tree_alloc_map_in_hole(struct IOVATreeAllocArgs *args) | |
198 | { | |
199 | const DMAMap *prev = args->prev, *this = args->this; | |
200 | uint64_t hole_start, hole_last; | |
201 | ||
202 | if (this && this->iova + this->size < args->iova_begin) { | |
203 | return; | |
204 | } | |
205 | ||
206 | hole_start = MAX(prev ? prev->iova + prev->size + 1 : 0, args->iova_begin); | |
207 | hole_last = this ? this->iova : HWADDR_MAX; | |
208 | ||
209 | if (hole_last - hole_start > args->new_size) { | |
210 | args->iova_result = hole_start; | |
211 | args->iova_found = true; | |
212 | } | |
213 | } | |
214 | ||
215 | /** | |
216 | * Foreach dma node in the tree, compare if there is a hole with its previous | |
217 | * node (or minimum iova address allowed) and the node. | |
218 | * | |
219 | * @key: Node iterating | |
220 | * @value: Node iterating | |
221 | * @pargs: Struct to communicate with the outside world | |
222 | * | |
223 | * Return: false to keep iterating, true if needs break. | |
224 | */ | |
225 | static gboolean iova_tree_alloc_traverse(gpointer key, gpointer value, | |
226 | gpointer pargs) | |
227 | { | |
228 | struct IOVATreeAllocArgs *args = pargs; | |
229 | DMAMap *node = value; | |
230 | ||
231 | assert(key == value); | |
232 | ||
233 | iova_tree_alloc_args_iterate(args, node); | |
234 | iova_tree_alloc_map_in_hole(args); | |
235 | return args->iova_found; | |
236 | } | |
237 | ||
238 | int iova_tree_alloc_map(IOVATree *tree, DMAMap *map, hwaddr iova_begin, | |
239 | hwaddr iova_last) | |
240 | { | |
241 | struct IOVATreeAllocArgs args = { | |
242 | .new_size = map->size, | |
243 | .iova_begin = iova_begin, | |
244 | }; | |
245 | ||
246 | if (unlikely(iova_last < iova_begin)) { | |
247 | return IOVA_ERR_INVALID; | |
248 | } | |
249 | ||
250 | /* | |
251 | * Find a valid hole for the mapping | |
252 | * | |
253 | * Assuming low iova_begin, so no need to do a binary search to | |
254 | * locate the first node. | |
255 | * | |
256 | * TODO: Replace all this with g_tree_node_first/next/last when available | |
257 | * (from glib since 2.68). To do it with g_tree_foreach complicates the | |
258 | * code a lot. | |
259 | * | |
260 | */ | |
261 | g_tree_foreach(tree->tree, iova_tree_alloc_traverse, &args); | |
262 | if (!args.iova_found) { | |
263 | /* | |
264 | * Either tree is empty or the last hole is still not checked. | |
265 | * g_tree_foreach does not compare (last, iova_last] range, so we check | |
266 | * it here. | |
267 | */ | |
268 | iova_tree_alloc_args_iterate(&args, NULL); | |
269 | iova_tree_alloc_map_in_hole(&args); | |
270 | } | |
271 | ||
272 | if (!args.iova_found || args.iova_result + map->size > iova_last) { | |
273 | return IOVA_ERR_NOMEM; | |
274 | } | |
275 | ||
276 | map->iova = args.iova_result; | |
277 | return iova_tree_insert(tree, map); | |
278 | } | |
279 | ||
eecf5eed PX |
280 | void iova_tree_destroy(IOVATree *tree) |
281 | { | |
282 | g_tree_destroy(tree->tree); | |
283 | g_free(tree); | |
284 | } |