File:  [Qemu by Fabrice Bellard] / qemu / xen-mapcache.c
Revision 1.1.1.2 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 19:16:42 2018 UTC (3 years, 1 month ago) by root
Branches: qemu, MAIN
CVS tags: qemu1001, HEAD
qemu 1.0.1

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

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