diff options
Diffstat (limited to 'xen-mapcache.c')
| -rw-r--r-- | xen-mapcache.c | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/xen-mapcache.c b/xen-mapcache.c new file mode 100644 index 0000000000..a539358fb7 --- /dev/null +++ b/xen-mapcache.c @@ -0,0 +1,349 @@ +/* + * 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 <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 +#elif defined(__x86_64__) +# define MCACHE_BUCKET_SHIFT 20 +#endif +#define MCACHE_BUCKET_SIZE (1UL << MCACHE_BUCKET_SHIFT) + +#define BITS_PER_LONG (sizeof(long) * 8) +#define BITS_TO_LONGS(bits) (((bits) + BITS_PER_LONG - 1) / BITS_PER_LONG) +#define DECLARE_BITMAP(name, bits) unsigned long name[BITS_TO_LONGS(bits)] + +typedef struct MapCacheEntry { + target_phys_addr_t paddr_index; + uint8_t *vaddr_base; + DECLARE_BITMAP(valid_mapping, MCACHE_BUCKET_SIZE >> XC_PAGE_SHIFT); + uint8_t lock; + struct MapCacheEntry *next; +} MapCacheEntry; + +typedef struct MapCacheRev { + uint8_t *vaddr_req; + target_phys_addr_t paddr_index; + 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_bit(unsigned int bit, const unsigned long *map) +{ + return !!((map)[(bit) / BITS_PER_LONG] & (1UL << ((bit) % BITS_PER_LONG))); +} + +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); + rlimit_as.rlim_cur = rlimit_as.rlim_max; + setrlimit(RLIMIT_AS, &rlimit_as); + mapcache->max_mcache_size = rlimit_as.rlim_max; + + 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, j; + 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, size) != 0) { + perror("unmap fails"); + exit(-1); + } + } + + 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; + + for (i = 0; i < nb_pfn; i += BITS_PER_LONG) { + unsigned long word = 0; + if ((i + BITS_PER_LONG) > nb_pfn) { + j = nb_pfn % BITS_PER_LONG; + } else { + j = BITS_PER_LONG; + } + while (j > 0) { + word = (word << 1) | !err[i + --j]; + } + entry->valid_mapping[i / BITS_PER_LONG] = word; + } + + 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); + + trace_qemu_map_cache(phys_addr); + + if (address_index == mapcache->last_address_index && !lock) { + trace_qemu_map_cache_return(mapcache->last_address_vaddr + address_offset); + return mapcache->last_address_vaddr + address_offset; + } + + entry = &mapcache->entry[address_index % mapcache->nr_buckets]; + + while (entry && entry->lock && entry->paddr_index != address_index && entry->vaddr_base) { + pentry = entry; + entry = entry->next; + } + if (!entry) { + entry = qemu_mallocz(sizeof (MapCacheEntry)); + pentry->next = entry; + qemu_remap_bucket(entry, size ? : MCACHE_BUCKET_SIZE, address_index); + } else if (!entry->lock) { + if (!entry->vaddr_base || entry->paddr_index != address_index || + !test_bit(address_offset >> XC_PAGE_SHIFT, entry->valid_mapping)) { + qemu_remap_bucket(entry, size ? : MCACHE_BUCKET_SIZE, address_index); + } + } + + if (!test_bit(address_offset >> 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; + 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) +{ + MapCacheRev *reventry; + target_phys_addr_t paddr_index; + int found = 0; + + QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) { + if (reventry->vaddr_req == ptr) { + paddr_index = reventry->paddr_index; + 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; + } + + return paddr_index << MCACHE_BUCKET_SHIFT; +} + +void qemu_invalidate_entry(uint8_t *buffer) +{ + MapCacheEntry *entry = NULL, *pentry = NULL; + MapCacheRev *reventry; + target_phys_addr_t paddr_index; + 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; + 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) { + 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, MCACHE_BUCKET_SIZE) != 0) { + perror("unmap fails"); + exit(-1); + } + 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, MCACHE_BUCKET_SIZE) != 0) { + perror("unmap fails"); + exit(-1); + } + + entry->paddr_index = 0; + entry->vaddr_base = NULL; + } + + mapcache->last_address_index = -1; + mapcache->last_address_vaddr = NULL; + + mapcache_unlock(); +} + +uint8_t *xen_map_block(target_phys_addr_t phys_addr, target_phys_addr_t size) +{ + uint8_t *vaddr_base; + xen_pfn_t *pfns; + int *err; + unsigned int i; + target_phys_addr_t nb_pfn = size >> XC_PAGE_SHIFT; + + trace_xen_map_block(phys_addr, size); + phys_addr >>= XC_PAGE_SHIFT; + + pfns = qemu_mallocz(nb_pfn * sizeof (xen_pfn_t)); + err = qemu_mallocz(nb_pfn * sizeof (int)); + + for (i = 0; i < nb_pfn; i++) { + pfns[i] = phys_addr + 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); + } + + qemu_free(pfns); + qemu_free(err); + + return vaddr_base; +} |