summaryrefslogtreecommitdiffstats
path: root/xen-mapcache.c
blob: fac47cd9be72bf1201f21745498625fec44c4515 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
/*
 * Copyright (C) 2011       Citrix Ltd.
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */

#include "config.h"

#include <sys/resource.h>

#include "hw/xen_backend.h"
#include "blockdev.h"
#include "bitmap.h"

#include <xen/hvm/params.h>
#include <sys/mman.h>

#include "xen-mapcache.h"
#include "trace.h"


//#define MAPCACHE_DEBUG

#ifdef MAPCACHE_DEBUG
#  define DPRINTF(fmt, ...) do { \
    fprintf(stderr, "xen_mapcache: " fmt, ## __VA_ARGS__); \
} while (0)
#else
#  define DPRINTF(fmt, ...) do { } while (0)
#endif

#if defined(__i386__)
#  define MCACHE_BUCKET_SHIFT 16
#  define MCACHE_MAX_SIZE     (1UL<<31) /* 2GB Cap */
#elif defined(__x86_64__)
#  define MCACHE_BUCKET_SHIFT 20
#  define MCACHE_MAX_SIZE     (1UL<<35) /* 32GB Cap */
#endif
#define MCACHE_BUCKET_SIZE (1UL << MCACHE_BUCKET_SHIFT)

typedef struct MapCacheEntry {
    target_phys_addr_t paddr_index;
    uint8_t *vaddr_base;
    unsigned long *valid_mapping;
    uint8_t lock;
    target_phys_addr_t size;
    struct MapCacheEntry *next;
} MapCacheEntry;

typedef struct MapCacheRev {
    uint8_t *vaddr_req;
    target_phys_addr_t paddr_index;
    target_phys_addr_t size;
    QTAILQ_ENTRY(MapCacheRev) next;
} MapCacheRev;

typedef struct MapCache {
    MapCacheEntry *entry;
    unsigned long nr_buckets;
    QTAILQ_HEAD(map_cache_head, MapCacheRev) locked_entries;

    /* For most cases (>99.9%), the page address is the same. */
    target_phys_addr_t last_address_index;
    uint8_t *last_address_vaddr;
    unsigned long max_mcache_size;
    unsigned int mcache_bucket_shift;
} MapCache;

static MapCache *mapcache;

static inline int test_bits(int nr, int size, const unsigned long *addr)
{
    unsigned long res = find_next_zero_bit(addr, size + nr, nr);
    if (res >= nr + size)
        return 1;
    else
        return 0;
}

void qemu_map_cache_init(void)
{
    unsigned long size;
    struct rlimit rlimit_as;

    mapcache = qemu_mallocz(sizeof (MapCache));

    QTAILQ_INIT(&mapcache->locked_entries);
    mapcache->last_address_index = -1;

    getrlimit(RLIMIT_AS, &rlimit_as);
    if (rlimit_as.rlim_max < MCACHE_MAX_SIZE) {
        rlimit_as.rlim_cur = rlimit_as.rlim_max;
    } else {
        rlimit_as.rlim_cur = MCACHE_MAX_SIZE;
    }

    setrlimit(RLIMIT_AS, &rlimit_as);
    mapcache->max_mcache_size = rlimit_as.rlim_cur;

    mapcache->nr_buckets =
        (((mapcache->max_mcache_size >> XC_PAGE_SHIFT) +
          (1UL << (MCACHE_BUCKET_SHIFT - XC_PAGE_SHIFT)) - 1) >>
         (MCACHE_BUCKET_SHIFT - XC_PAGE_SHIFT));

    size = mapcache->nr_buckets * sizeof (MapCacheEntry);
    size = (size + XC_PAGE_SIZE - 1) & ~(XC_PAGE_SIZE - 1);
    DPRINTF("qemu_map_cache_init, nr_buckets = %lx size %lu\n", mapcache->nr_buckets, size);
    mapcache->entry = qemu_mallocz(size);
}

static void qemu_remap_bucket(MapCacheEntry *entry,
                              target_phys_addr_t size,
                              target_phys_addr_t address_index)
{
    uint8_t *vaddr_base;
    xen_pfn_t *pfns;
    int *err;
    unsigned int i;
    target_phys_addr_t nb_pfn = size >> XC_PAGE_SHIFT;

    trace_qemu_remap_bucket(address_index);

    pfns = qemu_mallocz(nb_pfn * sizeof (xen_pfn_t));
    err = qemu_mallocz(nb_pfn * sizeof (int));

    if (entry->vaddr_base != NULL) {
        if (munmap(entry->vaddr_base, entry->size) != 0) {
            perror("unmap fails");
            exit(-1);
        }
    }
    if (entry->valid_mapping != NULL) {
        qemu_free(entry->valid_mapping);
        entry->valid_mapping = NULL;
    }

    for (i = 0; i < nb_pfn; i++) {
        pfns[i] = (address_index << (MCACHE_BUCKET_SHIFT-XC_PAGE_SHIFT)) + i;
    }

    vaddr_base = xc_map_foreign_bulk(xen_xc, xen_domid, PROT_READ|PROT_WRITE,
                                     pfns, err, nb_pfn);
    if (vaddr_base == NULL) {
        perror("xc_map_foreign_bulk");
        exit(-1);
    }

    entry->vaddr_base = vaddr_base;
    entry->paddr_index = address_index;
    entry->size = size;
    entry->valid_mapping = (unsigned long *) qemu_mallocz(sizeof(unsigned long) *
            BITS_TO_LONGS(size >> XC_PAGE_SHIFT));

    bitmap_zero(entry->valid_mapping, nb_pfn);
    for (i = 0; i < nb_pfn; i++) {
        if (!err[i]) {
            bitmap_set(entry->valid_mapping, i, 1);
        }
    }

    qemu_free(pfns);
    qemu_free(err);
}

uint8_t *qemu_map_cache(target_phys_addr_t phys_addr, target_phys_addr_t size, uint8_t lock)
{
    MapCacheEntry *entry, *pentry = NULL;
    target_phys_addr_t address_index  = phys_addr >> MCACHE_BUCKET_SHIFT;
    target_phys_addr_t address_offset = phys_addr & (MCACHE_BUCKET_SIZE - 1);
    target_phys_addr_t __size = size;

    trace_qemu_map_cache(phys_addr);

    if (address_index == mapcache->last_address_index && !lock && !__size) {
        trace_qemu_map_cache_return(mapcache->last_address_vaddr + address_offset);
        return mapcache->last_address_vaddr + address_offset;
    }

    /* size is always a multiple of MCACHE_BUCKET_SIZE */
    if ((address_offset + (__size % MCACHE_BUCKET_SIZE)) > MCACHE_BUCKET_SIZE)
        __size += MCACHE_BUCKET_SIZE;
    if (__size % MCACHE_BUCKET_SIZE)
        __size += MCACHE_BUCKET_SIZE - (__size % MCACHE_BUCKET_SIZE);
    if (!__size)
        __size = MCACHE_BUCKET_SIZE;

    entry = &mapcache->entry[address_index % mapcache->nr_buckets];

    while (entry && entry->lock && entry->vaddr_base &&
            (entry->paddr_index != address_index || entry->size != __size ||
             !test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT,
                 entry->valid_mapping))) {
        pentry = entry;
        entry = entry->next;
    }
    if (!entry) {
        entry = qemu_mallocz(sizeof (MapCacheEntry));
        pentry->next = entry;
        qemu_remap_bucket(entry, __size, address_index);
    } else if (!entry->lock) {
        if (!entry->vaddr_base || entry->paddr_index != address_index ||
                entry->size != __size ||
                !test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT,
                    entry->valid_mapping)) {
            qemu_remap_bucket(entry, __size, address_index);
        }
    }

    if(!test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT,
                entry->valid_mapping)) {
        mapcache->last_address_index = -1;
        trace_qemu_map_cache_return(NULL);
        return NULL;
    }

    mapcache->last_address_index = address_index;
    mapcache->last_address_vaddr = entry->vaddr_base;
    if (lock) {
        MapCacheRev *reventry = qemu_mallocz(sizeof(MapCacheRev));
        entry->lock++;
        reventry->vaddr_req = mapcache->last_address_vaddr + address_offset;
        reventry->paddr_index = mapcache->last_address_index;
        reventry->size = entry->size;
        QTAILQ_INSERT_HEAD(&mapcache->locked_entries, reventry, next);
    }

    trace_qemu_map_cache_return(mapcache->last_address_vaddr + address_offset);
    return mapcache->last_address_vaddr + address_offset;
}

ram_addr_t qemu_ram_addr_from_mapcache(void *ptr)
{
    MapCacheEntry *entry = NULL, *pentry = NULL;
    MapCacheRev *reventry;
    target_phys_addr_t paddr_index;
    target_phys_addr_t size;
    int found = 0;

    QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
        if (reventry->vaddr_req == ptr) {
            paddr_index = reventry->paddr_index;
            size = reventry->size;
            found = 1;
            break;
        }
    }
    if (!found) {
        fprintf(stderr, "qemu_ram_addr_from_mapcache, could not find %p\n", ptr);
        QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
            DPRINTF("   "TARGET_FMT_plx" -> %p is present\n", reventry->paddr_index,
                    reventry->vaddr_req);
        }
        abort();
        return 0;
    }

    entry = &mapcache->entry[paddr_index % mapcache->nr_buckets];
    while (entry && (entry->paddr_index != paddr_index || entry->size != size)) {
        pentry = entry;
        entry = entry->next;
    }
    if (!entry) {
        DPRINTF("Trying to find address %p that is not in the mapcache!\n", ptr);
        return 0;
    }
    return (reventry->paddr_index << MCACHE_BUCKET_SHIFT) +
        ((unsigned long) ptr - (unsigned long) entry->vaddr_base);
}

void qemu_invalidate_entry(uint8_t *buffer)
{
    MapCacheEntry *entry = NULL, *pentry = NULL;
    MapCacheRev *reventry;
    target_phys_addr_t paddr_index;
    target_phys_addr_t size;
    int found = 0;

    if (mapcache->last_address_vaddr == buffer) {
        mapcache->last_address_index = -1;
    }

    QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
        if (reventry->vaddr_req == buffer) {
            paddr_index = reventry->paddr_index;
            size = reventry->size;
            found = 1;
            break;
        }
    }
    if (!found) {
        DPRINTF("qemu_invalidate_entry, could not find %p\n", buffer);
        QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
            DPRINTF("   "TARGET_FMT_plx" -> %p is present\n", reventry->paddr_index, reventry->vaddr_req);
        }
        return;
    }
    QTAILQ_REMOVE(&mapcache->locked_entries, reventry, next);
    qemu_free(reventry);

    entry = &mapcache->entry[paddr_index % mapcache->nr_buckets];
    while (entry && (entry->paddr_index != paddr_index || entry->size != size)) {
        pentry = entry;
        entry = entry->next;
    }
    if (!entry) {
        DPRINTF("Trying to unmap address %p that is not in the mapcache!\n", buffer);
        return;
    }
    entry->lock--;
    if (entry->lock > 0 || pentry == NULL) {
        return;
    }

    pentry->next = entry->next;
    if (munmap(entry->vaddr_base, entry->size) != 0) {
        perror("unmap fails");
        exit(-1);
    }
    qemu_free(entry->valid_mapping);
    qemu_free(entry);
}

void qemu_invalidate_map_cache(void)
{
    unsigned long i;
    MapCacheRev *reventry;

    /* Flush pending AIO before destroying the mapcache */
    qemu_aio_flush();

    QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
        DPRINTF("There should be no locked mappings at this time, "
                "but "TARGET_FMT_plx" -> %p is present\n",
                reventry->paddr_index, reventry->vaddr_req);
    }

    mapcache_lock();

    for (i = 0; i < mapcache->nr_buckets; i++) {
        MapCacheEntry *entry = &mapcache->entry[i];

        if (entry->vaddr_base == NULL) {
            continue;
        }

        if (munmap(entry->vaddr_base, entry->size) != 0) {
            perror("unmap fails");
            exit(-1);
        }

        entry->paddr_index = 0;
        entry->vaddr_base = NULL;
        entry->size = 0;
        qemu_free(entry->valid_mapping);
        entry->valid_mapping = NULL;
    }

    mapcache->last_address_index = -1;
    mapcache->last_address_vaddr = NULL;

    mapcache_unlock();
}