vga: improve documentation
[qemu.git] / xen-mapcache.c
1 /*
2 * Copyright (C) 2011 Citrix Ltd.
3 *
4 * This work is licensed under the terms of the GNU GPL, version 2. See
5 * the COPYING file in the top-level directory.
6 *
7 * Contributions after 2012-01-13 are licensed under the terms of the
8 * GNU GPL, version 2 or (at your option) any later version.
9 */
10
11 #include "config.h"
12
13 #include <sys/resource.h>
14
15 #include "hw/xen_backend.h"
16 #include "blockdev.h"
17 #include "bitmap.h"
18
19 #include <xen/hvm/params.h>
20 #include <sys/mman.h>
21
22 #include "xen-mapcache.h"
23 #include "trace.h"
24
25
26 //#define MAPCACHE_DEBUG
27
28 #ifdef MAPCACHE_DEBUG
29 # define DPRINTF(fmt, ...) do { \
30 fprintf(stderr, "xen_mapcache: " fmt, ## __VA_ARGS__); \
31 } while (0)
32 #else
33 # define DPRINTF(fmt, ...) do { } while (0)
34 #endif
35
36 #if defined(__i386__)
37 # define MCACHE_BUCKET_SHIFT 16
38 # define MCACHE_MAX_SIZE (1UL<<31) /* 2GB Cap */
39 #elif defined(__x86_64__)
40 # define MCACHE_BUCKET_SHIFT 20
41 # define MCACHE_MAX_SIZE (1UL<<35) /* 32GB Cap */
42 #endif
43 #define MCACHE_BUCKET_SIZE (1UL << MCACHE_BUCKET_SHIFT)
44
45 /* This is the size of the virtual address space reserve to QEMU that will not
46 * be use by MapCache.
47 * From empirical tests I observed that qemu use 75MB more than the
48 * max_mcache_size.
49 */
50 #define NON_MCACHE_MEMORY_SIZE (80 * 1024 * 1024)
51
52 #define mapcache_lock() ((void)0)
53 #define mapcache_unlock() ((void)0)
54
55 typedef struct MapCacheEntry {
56 target_phys_addr_t paddr_index;
57 uint8_t *vaddr_base;
58 unsigned long *valid_mapping;
59 uint8_t lock;
60 target_phys_addr_t size;
61 struct MapCacheEntry *next;
62 } MapCacheEntry;
63
64 typedef struct MapCacheRev {
65 uint8_t *vaddr_req;
66 target_phys_addr_t paddr_index;
67 target_phys_addr_t size;
68 QTAILQ_ENTRY(MapCacheRev) next;
69 } MapCacheRev;
70
71 typedef struct MapCache {
72 MapCacheEntry *entry;
73 unsigned long nr_buckets;
74 QTAILQ_HEAD(map_cache_head, MapCacheRev) locked_entries;
75
76 /* For most cases (>99.9%), the page address is the same. */
77 target_phys_addr_t last_address_index;
78 uint8_t *last_address_vaddr;
79 unsigned long max_mcache_size;
80 unsigned int mcache_bucket_shift;
81 } MapCache;
82
83 static MapCache *mapcache;
84
85 static inline int test_bits(int nr, int size, const unsigned long *addr)
86 {
87 unsigned long res = find_next_zero_bit(addr, size + nr, nr);
88 if (res >= nr + size)
89 return 1;
90 else
91 return 0;
92 }
93
94 void xen_map_cache_init(void)
95 {
96 unsigned long size;
97 struct rlimit rlimit_as;
98
99 mapcache = g_malloc0(sizeof (MapCache));
100
101 QTAILQ_INIT(&mapcache->locked_entries);
102 mapcache->last_address_index = -1;
103
104 if (geteuid() == 0) {
105 rlimit_as.rlim_cur = RLIM_INFINITY;
106 rlimit_as.rlim_max = RLIM_INFINITY;
107 mapcache->max_mcache_size = MCACHE_MAX_SIZE;
108 } else {
109 getrlimit(RLIMIT_AS, &rlimit_as);
110 rlimit_as.rlim_cur = rlimit_as.rlim_max;
111
112 if (rlimit_as.rlim_max != RLIM_INFINITY) {
113 fprintf(stderr, "Warning: QEMU's maximum size of virtual"
114 " memory is not infinity.\n");
115 }
116 if (rlimit_as.rlim_max < MCACHE_MAX_SIZE + NON_MCACHE_MEMORY_SIZE) {
117 mapcache->max_mcache_size = rlimit_as.rlim_max -
118 NON_MCACHE_MEMORY_SIZE;
119 } else {
120 mapcache->max_mcache_size = MCACHE_MAX_SIZE;
121 }
122 }
123
124 setrlimit(RLIMIT_AS, &rlimit_as);
125
126 mapcache->nr_buckets =
127 (((mapcache->max_mcache_size >> XC_PAGE_SHIFT) +
128 (1UL << (MCACHE_BUCKET_SHIFT - XC_PAGE_SHIFT)) - 1) >>
129 (MCACHE_BUCKET_SHIFT - XC_PAGE_SHIFT));
130
131 size = mapcache->nr_buckets * sizeof (MapCacheEntry);
132 size = (size + XC_PAGE_SIZE - 1) & ~(XC_PAGE_SIZE - 1);
133 DPRINTF("%s, nr_buckets = %lx size %lu\n", __func__,
134 mapcache->nr_buckets, size);
135 mapcache->entry = g_malloc0(size);
136 }
137
138 static void xen_remap_bucket(MapCacheEntry *entry,
139 target_phys_addr_t size,
140 target_phys_addr_t address_index)
141 {
142 uint8_t *vaddr_base;
143 xen_pfn_t *pfns;
144 int *err;
145 unsigned int i;
146 target_phys_addr_t nb_pfn = size >> XC_PAGE_SHIFT;
147
148 trace_xen_remap_bucket(address_index);
149
150 pfns = g_malloc0(nb_pfn * sizeof (xen_pfn_t));
151 err = g_malloc0(nb_pfn * sizeof (int));
152
153 if (entry->vaddr_base != NULL) {
154 if (munmap(entry->vaddr_base, entry->size) != 0) {
155 perror("unmap fails");
156 exit(-1);
157 }
158 }
159 if (entry->valid_mapping != NULL) {
160 g_free(entry->valid_mapping);
161 entry->valid_mapping = NULL;
162 }
163
164 for (i = 0; i < nb_pfn; i++) {
165 pfns[i] = (address_index << (MCACHE_BUCKET_SHIFT-XC_PAGE_SHIFT)) + i;
166 }
167
168 vaddr_base = xc_map_foreign_bulk(xen_xc, xen_domid, PROT_READ|PROT_WRITE,
169 pfns, err, nb_pfn);
170 if (vaddr_base == NULL) {
171 perror("xc_map_foreign_bulk");
172 exit(-1);
173 }
174
175 entry->vaddr_base = vaddr_base;
176 entry->paddr_index = address_index;
177 entry->size = size;
178 entry->valid_mapping = (unsigned long *) g_malloc0(sizeof(unsigned long) *
179 BITS_TO_LONGS(size >> XC_PAGE_SHIFT));
180
181 bitmap_zero(entry->valid_mapping, nb_pfn);
182 for (i = 0; i < nb_pfn; i++) {
183 if (!err[i]) {
184 bitmap_set(entry->valid_mapping, i, 1);
185 }
186 }
187
188 g_free(pfns);
189 g_free(err);
190 }
191
192 uint8_t *xen_map_cache(target_phys_addr_t phys_addr, target_phys_addr_t size,
193 uint8_t lock)
194 {
195 MapCacheEntry *entry, *pentry = NULL;
196 target_phys_addr_t address_index = phys_addr >> MCACHE_BUCKET_SHIFT;
197 target_phys_addr_t address_offset = phys_addr & (MCACHE_BUCKET_SIZE - 1);
198 target_phys_addr_t __size = size;
199
200 trace_xen_map_cache(phys_addr);
201
202 if (address_index == mapcache->last_address_index && !lock && !__size) {
203 trace_xen_map_cache_return(mapcache->last_address_vaddr + address_offset);
204 return mapcache->last_address_vaddr + address_offset;
205 }
206
207 /* size is always a multiple of MCACHE_BUCKET_SIZE */
208 if ((address_offset + (__size % MCACHE_BUCKET_SIZE)) > MCACHE_BUCKET_SIZE)
209 __size += MCACHE_BUCKET_SIZE;
210 if (__size % MCACHE_BUCKET_SIZE)
211 __size += MCACHE_BUCKET_SIZE - (__size % MCACHE_BUCKET_SIZE);
212 if (!__size)
213 __size = MCACHE_BUCKET_SIZE;
214
215 entry = &mapcache->entry[address_index % mapcache->nr_buckets];
216
217 while (entry && entry->lock && entry->vaddr_base &&
218 (entry->paddr_index != address_index || entry->size != __size ||
219 !test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT,
220 entry->valid_mapping))) {
221 pentry = entry;
222 entry = entry->next;
223 }
224 if (!entry) {
225 entry = g_malloc0(sizeof (MapCacheEntry));
226 pentry->next = entry;
227 xen_remap_bucket(entry, __size, address_index);
228 } else if (!entry->lock) {
229 if (!entry->vaddr_base || entry->paddr_index != address_index ||
230 entry->size != __size ||
231 !test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT,
232 entry->valid_mapping)) {
233 xen_remap_bucket(entry, __size, address_index);
234 }
235 }
236
237 if(!test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT,
238 entry->valid_mapping)) {
239 mapcache->last_address_index = -1;
240 trace_xen_map_cache_return(NULL);
241 return NULL;
242 }
243
244 mapcache->last_address_index = address_index;
245 mapcache->last_address_vaddr = entry->vaddr_base;
246 if (lock) {
247 MapCacheRev *reventry = g_malloc0(sizeof(MapCacheRev));
248 entry->lock++;
249 reventry->vaddr_req = mapcache->last_address_vaddr + address_offset;
250 reventry->paddr_index = mapcache->last_address_index;
251 reventry->size = entry->size;
252 QTAILQ_INSERT_HEAD(&mapcache->locked_entries, reventry, next);
253 }
254
255 trace_xen_map_cache_return(mapcache->last_address_vaddr + address_offset);
256 return mapcache->last_address_vaddr + address_offset;
257 }
258
259 ram_addr_t xen_ram_addr_from_mapcache(void *ptr)
260 {
261 MapCacheEntry *entry = NULL;
262 MapCacheRev *reventry;
263 target_phys_addr_t paddr_index;
264 target_phys_addr_t size;
265 int found = 0;
266
267 QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
268 if (reventry->vaddr_req == ptr) {
269 paddr_index = reventry->paddr_index;
270 size = reventry->size;
271 found = 1;
272 break;
273 }
274 }
275 if (!found) {
276 fprintf(stderr, "%s, could not find %p\n", __func__, ptr);
277 QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
278 DPRINTF(" "TARGET_FMT_plx" -> %p is present\n", reventry->paddr_index,
279 reventry->vaddr_req);
280 }
281 abort();
282 return 0;
283 }
284
285 entry = &mapcache->entry[paddr_index % mapcache->nr_buckets];
286 while (entry && (entry->paddr_index != paddr_index || entry->size != size)) {
287 entry = entry->next;
288 }
289 if (!entry) {
290 DPRINTF("Trying to find address %p that is not in the mapcache!\n", ptr);
291 return 0;
292 }
293 return (reventry->paddr_index << MCACHE_BUCKET_SHIFT) +
294 ((unsigned long) ptr - (unsigned long) entry->vaddr_base);
295 }
296
297 void xen_invalidate_map_cache_entry(uint8_t *buffer)
298 {
299 MapCacheEntry *entry = NULL, *pentry = NULL;
300 MapCacheRev *reventry;
301 target_phys_addr_t paddr_index;
302 target_phys_addr_t size;
303 int found = 0;
304
305 if (mapcache->last_address_vaddr == buffer) {
306 mapcache->last_address_index = -1;
307 }
308
309 QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
310 if (reventry->vaddr_req == buffer) {
311 paddr_index = reventry->paddr_index;
312 size = reventry->size;
313 found = 1;
314 break;
315 }
316 }
317 if (!found) {
318 DPRINTF("%s, could not find %p\n", __func__, buffer);
319 QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
320 DPRINTF(" "TARGET_FMT_plx" -> %p is present\n", reventry->paddr_index, reventry->vaddr_req);
321 }
322 return;
323 }
324 QTAILQ_REMOVE(&mapcache->locked_entries, reventry, next);
325 g_free(reventry);
326
327 entry = &mapcache->entry[paddr_index % mapcache->nr_buckets];
328 while (entry && (entry->paddr_index != paddr_index || entry->size != size)) {
329 pentry = entry;
330 entry = entry->next;
331 }
332 if (!entry) {
333 DPRINTF("Trying to unmap address %p that is not in the mapcache!\n", buffer);
334 return;
335 }
336 entry->lock--;
337 if (entry->lock > 0 || pentry == NULL) {
338 return;
339 }
340
341 pentry->next = entry->next;
342 if (munmap(entry->vaddr_base, entry->size) != 0) {
343 perror("unmap fails");
344 exit(-1);
345 }
346 g_free(entry->valid_mapping);
347 g_free(entry);
348 }
349
350 void xen_invalidate_map_cache(void)
351 {
352 unsigned long i;
353 MapCacheRev *reventry;
354
355 /* Flush pending AIO before destroying the mapcache */
356 bdrv_drain_all();
357
358 QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
359 DPRINTF("There should be no locked mappings at this time, "
360 "but "TARGET_FMT_plx" -> %p is present\n",
361 reventry->paddr_index, reventry->vaddr_req);
362 }
363
364 mapcache_lock();
365
366 for (i = 0; i < mapcache->nr_buckets; i++) {
367 MapCacheEntry *entry = &mapcache->entry[i];
368
369 if (entry->vaddr_base == NULL) {
370 continue;
371 }
372
373 if (munmap(entry->vaddr_base, entry->size) != 0) {
374 perror("unmap fails");
375 exit(-1);
376 }
377
378 entry->paddr_index = 0;
379 entry->vaddr_base = NULL;
380 entry->size = 0;
381 g_free(entry->valid_mapping);
382 entry->valid_mapping = NULL;
383 }
384
385 mapcache->last_address_index = -1;
386 mapcache->last_address_vaddr = NULL;
387
388 mapcache_unlock();
389 }