qemu/xen-mapcache.c
Anthony PERARD 050a0ddf39 Introduce qemu_put_ram_ptr
This function allows to unlock a ram_ptr give by qemu_get_ram_ptr. After
a call to qemu_put_ram_ptr, the pointer may be unmap from QEMU when
used with Xen.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
2011-05-08 10:10:01 +02:00

376 lines
10 KiB
C

/*
* 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;
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;
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, 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;
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);
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;
}
void qemu_map_cache_unlock(void *buffer)
{
MapCacheEntry *entry = NULL, *pentry = NULL;
MapCacheRev *reventry;
target_phys_addr_t paddr_index;
int found = 0;
QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
if (reventry->vaddr_req == buffer) {
paddr_index = reventry->paddr_index;
found = 1;
break;
}
}
if (!found) {
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) {
return;
}
if (entry->lock > 0) {
entry->lock--;
}
}
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;
}