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xen: fix qemu_map_cache with size != MCACHE_BUCKET_SIZE

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Fix the implementation of qemu_map_cache: correctly support size
arguments different from 0 or MCACHE_BUCKET_SIZE.
The new implementation supports locked mapcache entries with size
multiple of MCACHE_BUCKET_SIZE. qemu_invalidate_entry can correctly
find and unmap these "large" mapcache entries given that the virtual
address passed to qemu_invalidate_entry is the same returned by
qemu_map_cache when the locked mapcache entry was created.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Stefano Stabellini 2011-05-19 18:35:42 +01:00 committed by Alexander Graf
parent b4dd7802ca
commit c13390cd38
1 changed files with 65 additions and 12 deletions
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77
xen-mapcache.c
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@ -43,14 +43,16 @@
typedef struct MapCacheEntry {
target_phys_addr_t paddr_index;
uint8_t *vaddr_base;
DECLARE_BITMAP(valid_mapping, MCACHE_BUCKET_SIZE >> XC_PAGE_SHIFT);
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;
@ -68,6 +70,15 @@ typedef struct 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;
@ -115,11 +126,15 @@ static void qemu_remap_bucket(MapCacheEntry *entry,
err = qemu_mallocz(nb_pfn * sizeof (int));
if (entry->vaddr_base != NULL) {
if (munmap(entry->vaddr_base, size) != 0) {
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;
@ -134,6 +149,9 @@ static void qemu_remap_bucket(MapCacheEntry *entry,
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++) {
@ -151,32 +169,47 @@ uint8_t *qemu_map_cache(target_phys_addr_t phys_addr, target_phys_addr_t size, u
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) {
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->paddr_index != address_index && entry->vaddr_base) {
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 ? : MCACHE_BUCKET_SIZE, address_index);
qemu_remap_bucket(entry, __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);
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_bit(address_offset >> XC_PAGE_SHIFT, entry->valid_mapping)) {
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;
@ -189,6 +222,7 @@ uint8_t *qemu_map_cache(target_phys_addr_t phys_addr, target_phys_addr_t size, u
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);
}
@ -231,13 +265,16 @@ void qemu_map_cache_unlock(void *buffer)
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;
}
@ -252,7 +289,17 @@ ram_addr_t qemu_ram_addr_from_mapcache(void *ptr)
return 0;
}
return paddr_index << MCACHE_BUCKET_SHIFT;
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)
@ -260,6 +307,7 @@ 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) {
@ -269,6 +317,7 @@ void qemu_invalidate_entry(uint8_t *buffer)
QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
if (reventry->vaddr_req == buffer) {
paddr_index = reventry->paddr_index;
size = reventry->size;
found = 1;
break;
}
@ -284,7 +333,7 @@ void qemu_invalidate_entry(uint8_t *buffer)
qemu_free(reventry);
entry = &mapcache->entry[paddr_index % mapcache->nr_buckets];
while (entry && entry->paddr_index != paddr_index) {
while (entry && (entry->paddr_index != paddr_index || entry->size != size)) {
pentry = entry;
entry = entry->next;
}
@ -298,10 +347,11 @@ void qemu_invalidate_entry(uint8_t *buffer)
}
pentry->next = entry->next;
if (munmap(entry->vaddr_base, MCACHE_BUCKET_SIZE) != 0) {
if (munmap(entry->vaddr_base, entry->size) != 0) {
perror("unmap fails");
exit(-1);
}
qemu_free(entry->valid_mapping);
qemu_free(entry);
}
@ -328,13 +378,16 @@ void qemu_invalidate_map_cache(void)
continue;
}
if (munmap(entry->vaddr_base, MCACHE_BUCKET_SIZE) != 0) {
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;