Annotation of qemu/xen-mapcache.c, revision 1.1.1.1

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

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