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qemu-e2k/hw/i386/xen/xen-mapcache.c

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/*
* 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.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "qemu/osdep.h"
#include "qemu/units.h"
#include "qemu/error-report.h"
#include <sys/resource.h>
#include "hw/xen/xen-legacy-backend.h"
#include "qemu/bitmap.h"
#include "sysemu/runstate.h"
#include "sysemu/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 HOST_LONG_BITS == 32
# define MCACHE_BUCKET_SHIFT 16
# define MCACHE_MAX_SIZE (1UL<<31) /* 2GB Cap */
#else
# define MCACHE_BUCKET_SHIFT 20
# define MCACHE_MAX_SIZE (1UL<<35) /* 32GB Cap */
#endif
#define MCACHE_BUCKET_SIZE (1UL << MCACHE_BUCKET_SHIFT)
/* This is the size of the virtual address space reserve to QEMU that will not
* be use by MapCache.
* From empirical tests I observed that qemu use 75MB more than the
* max_mcache_size.
*/
#define NON_MCACHE_MEMORY_SIZE (80 * MiB)
typedef struct MapCacheEntry {
hwaddr paddr_index;
uint8_t *vaddr_base;
unsigned long *valid_mapping;
uint32_t lock;
#define XEN_MAPCACHE_ENTRY_DUMMY (1 << 0)
uint8_t flags;
hwaddr size;
struct MapCacheEntry *next;
} MapCacheEntry;
typedef struct MapCacheRev {
uint8_t *vaddr_req;
hwaddr paddr_index;
hwaddr size;
QTAILQ_ENTRY(MapCacheRev) next;
bool dma;
} MapCacheRev;
typedef struct MapCache {
MapCacheEntry *entry;
unsigned long nr_buckets;
QTAILQ_HEAD(, MapCacheRev) locked_entries;
/* For most cases (>99.9%), the page address is the same. */
MapCacheEntry *last_entry;
unsigned long max_mcache_size;
unsigned int mcache_bucket_shift;
phys_offset_to_gaddr_t phys_offset_to_gaddr;
QemuMutex lock;
void *opaque;
} MapCache;
static MapCache *mapcache;
static inline void mapcache_lock(void)
{
qemu_mutex_lock(&mapcache->lock);
}
static inline void mapcache_unlock(void)
{
qemu_mutex_unlock(&mapcache->lock);
}
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 xen_map_cache_init(phys_offset_to_gaddr_t f, void *opaque)
{
unsigned long size;
struct rlimit rlimit_as;
mapcache = g_new0(MapCache, 1);
mapcache->phys_offset_to_gaddr = f;
mapcache->opaque = opaque;
qemu_mutex_init(&mapcache->lock);
QTAILQ_INIT(&mapcache->locked_entries);
if (geteuid() == 0) {
rlimit_as.rlim_cur = RLIM_INFINITY;
rlimit_as.rlim_max = RLIM_INFINITY;
mapcache->max_mcache_size = MCACHE_MAX_SIZE;
} else {
getrlimit(RLIMIT_AS, &rlimit_as);
rlimit_as.rlim_cur = rlimit_as.rlim_max;
if (rlimit_as.rlim_max != RLIM_INFINITY) {
warn_report("QEMU's maximum size of virtual"
" memory is not infinity");
}
if (rlimit_as.rlim_max < MCACHE_MAX_SIZE + NON_MCACHE_MEMORY_SIZE) {
mapcache->max_mcache_size = rlimit_as.rlim_max -
NON_MCACHE_MEMORY_SIZE;
} else {
mapcache->max_mcache_size = MCACHE_MAX_SIZE;
}
}
setrlimit(RLIMIT_AS, &rlimit_as);
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("%s, nr_buckets = %lx size %lu\n", __func__,
mapcache->nr_buckets, size);
mapcache->entry = g_malloc0(size);
}
static void xen_remap_bucket(MapCacheEntry *entry,
void *vaddr,
hwaddr size,
hwaddr address_index,
bool dummy)
{
uint8_t *vaddr_base;
xen_pfn_t *pfns;
int *err;
unsigned int i;
hwaddr nb_pfn = size >> XC_PAGE_SHIFT;
trace_xen_remap_bucket(address_index);
pfns = g_new0(xen_pfn_t, nb_pfn);
err = g_new0(int, nb_pfn);
if (entry->vaddr_base != NULL) {
if (!(entry->flags & XEN_MAPCACHE_ENTRY_DUMMY)) {
ram_block_notify_remove(entry->vaddr_base, entry->size,
entry->size);
}
/*
* If an entry is being replaced by another mapping and we're using
* MAP_FIXED flag for it - there is possibility of a race for vaddr
* address with another thread doing an mmap call itself
* (see man 2 mmap). To avoid that we skip explicit unmapping here
* and allow the kernel to destroy the previous mappings by replacing
* them in mmap call later.
*
* Non-identical replacements are not allowed therefore.
*/
assert(!vaddr || (entry->vaddr_base == vaddr && entry->size == size));
if (!vaddr && munmap(entry->vaddr_base, entry->size) != 0) {
perror("unmap fails");
exit(-1);
}
}
g_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;
}
/*
* If the caller has requested the mapping at a specific address use
* MAP_FIXED to make sure it's honored.
*/
if (!dummy) {
vaddr_base = xenforeignmemory_map2(xen_fmem, xen_domid, vaddr,
PROT_READ | PROT_WRITE,
vaddr ? MAP_FIXED : 0,
nb_pfn, pfns, err);
if (vaddr_base == NULL) {
perror("xenforeignmemory_map2");
exit(-1);
}
} else {
/*
* We create dummy mappings where we are unable to create a foreign
* mapping immediately due to certain circumstances (i.e. on resume now)
*/
vaddr_base = mmap(vaddr, size, PROT_READ | PROT_WRITE,
MAP_ANON | MAP_SHARED | (vaddr ? MAP_FIXED : 0),
-1, 0);
if (vaddr_base == MAP_FAILED) {
perror("mmap");
exit(-1);
}
}
if (!(entry->flags & XEN_MAPCACHE_ENTRY_DUMMY)) {
ram_block_notify_add(vaddr_base, size, size);
}
entry->vaddr_base = vaddr_base;
entry->paddr_index = address_index;
entry->size = size;
entry->valid_mapping = g_new0(unsigned long,
BITS_TO_LONGS(size >> XC_PAGE_SHIFT));
if (dummy) {
entry->flags |= XEN_MAPCACHE_ENTRY_DUMMY;
} else {
entry->flags &= ~(XEN_MAPCACHE_ENTRY_DUMMY);
}
bitmap_zero(entry->valid_mapping, nb_pfn);
for (i = 0; i < nb_pfn; i++) {
if (!err[i]) {
bitmap_set(entry->valid_mapping, i, 1);
}
}
g_free(pfns);
g_free(err);
}
static uint8_t *xen_map_cache_unlocked(hwaddr phys_addr, hwaddr size,
uint8_t lock, bool dma)
{
MapCacheEntry *entry, *pentry = NULL,
*free_entry = NULL, *free_pentry = NULL;
hwaddr address_index;
hwaddr address_offset;
hwaddr cache_size = size;
hwaddr test_bit_size;
bool translated G_GNUC_UNUSED = false;
bool dummy = false;
tryagain:
address_index = phys_addr >> MCACHE_BUCKET_SHIFT;
address_offset = phys_addr & (MCACHE_BUCKET_SIZE - 1);
trace_xen_map_cache(phys_addr);
/* test_bit_size is always a multiple of XC_PAGE_SIZE */
if (size) {
test_bit_size = size + (phys_addr & (XC_PAGE_SIZE - 1));
if (test_bit_size % XC_PAGE_SIZE) {
test_bit_size += XC_PAGE_SIZE - (test_bit_size % XC_PAGE_SIZE);
}
} else {
test_bit_size = XC_PAGE_SIZE;
}
if (mapcache->last_entry != NULL &&
mapcache->last_entry->paddr_index == address_index &&
!lock && !size &&
test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
mapcache->last_entry->valid_mapping)) {
trace_xen_map_cache_return(mapcache->last_entry->vaddr_base + address_offset);
return mapcache->last_entry->vaddr_base + address_offset;
}
/* size is always a multiple of MCACHE_BUCKET_SIZE */
if (size) {
cache_size = size + address_offset;
if (cache_size % MCACHE_BUCKET_SIZE) {
cache_size += MCACHE_BUCKET_SIZE - (cache_size % MCACHE_BUCKET_SIZE);
}
} else {
cache_size = MCACHE_BUCKET_SIZE;
}
entry = &mapcache->entry[address_index % mapcache->nr_buckets];
while (entry && (lock || entry->lock) && entry->vaddr_base &&
(entry->paddr_index != address_index || entry->size != cache_size ||
!test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping))) {
if (!free_entry && !entry->lock) {
free_entry = entry;
free_pentry = pentry;
}
pentry = entry;
entry = entry->next;
}
if (!entry && free_entry) {
entry = free_entry;
pentry = free_pentry;
}
if (!entry) {
entry = g_new0(MapCacheEntry, 1);
pentry->next = entry;
xen_remap_bucket(entry, NULL, cache_size, address_index, dummy);
} else if (!entry->lock) {
if (!entry->vaddr_base || entry->paddr_index != address_index ||
entry->size != cache_size ||
!test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping)) {
xen_remap_bucket(entry, NULL, cache_size, address_index, dummy);
}
}
if(!test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping)) {
mapcache->last_entry = NULL;
#ifdef XEN_COMPAT_PHYSMAP
if (!translated && mapcache->phys_offset_to_gaddr) {
phys_addr = mapcache->phys_offset_to_gaddr(phys_addr, size);
translated = true;
goto tryagain;
}
#endif
if (!dummy && runstate_check(RUN_STATE_INMIGRATE)) {
dummy = true;
goto tryagain;
}
trace_xen_map_cache_return(NULL);
return NULL;
}
mapcache->last_entry = entry;
if (lock) {
MapCacheRev *reventry = g_new0(MapCacheRev, 1);
entry->lock++;
if (entry->lock == 0) {
fprintf(stderr,
"mapcache entry lock overflow: "TARGET_FMT_plx" -> %p\n",
entry->paddr_index, entry->vaddr_base);
abort();
}
reventry->dma = dma;
reventry->vaddr_req = mapcache->last_entry->vaddr_base + address_offset;
reventry->paddr_index = mapcache->last_entry->paddr_index;
reventry->size = entry->size;
QTAILQ_INSERT_HEAD(&mapcache->locked_entries, reventry, next);
}
trace_xen_map_cache_return(mapcache->last_entry->vaddr_base + address_offset);
return mapcache->last_entry->vaddr_base + address_offset;
}
uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size,
uint8_t lock, bool dma)
{
uint8_t *p;
mapcache_lock();
p = xen_map_cache_unlocked(phys_addr, size, lock, dma);
mapcache_unlock();
return p;
}
ram_addr_t xen_ram_addr_from_mapcache(void *ptr)
{
MapCacheEntry *entry = NULL;
MapCacheRev *reventry;
hwaddr paddr_index;
hwaddr size;
ram_addr_t raddr;
int found = 0;
mapcache_lock();
QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
if (reventry->vaddr_req == ptr) {
paddr_index = reventry->paddr_index;
size = reventry->size;
found = 1;
break;
}
}
if (!found) {
fprintf(stderr, "%s, could not find %p\n", __func__, 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;
}
entry = &mapcache->entry[paddr_index % mapcache->nr_buckets];
while (entry && (entry->paddr_index != paddr_index || entry->size != size)) {
entry = entry->next;
}
if (!entry) {
DPRINTF("Trying to find address %p that is not in the mapcache!\n", ptr);
raddr = 0;
} else {
raddr = (reventry->paddr_index << MCACHE_BUCKET_SHIFT) +
((unsigned long) ptr - (unsigned long) entry->vaddr_base);
}
mapcache_unlock();
return raddr;
}
static void xen_invalidate_map_cache_entry_unlocked(uint8_t *buffer)
{
MapCacheEntry *entry = NULL, *pentry = NULL;
MapCacheRev *reventry;
hwaddr paddr_index;
hwaddr size;
int found = 0;
QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
if (reventry->vaddr_req == buffer) {
paddr_index = reventry->paddr_index;
size = reventry->size;
found = 1;
break;
}
}
if (!found) {
DPRINTF("%s, could not find %p\n", __func__, 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);
g_free(reventry);
if (mapcache->last_entry != NULL &&
mapcache->last_entry->paddr_index == paddr_index) {
mapcache->last_entry = NULL;
}
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 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;
ram_block_notify_remove(entry->vaddr_base, entry->size, entry->size);
if (munmap(entry->vaddr_base, entry->size) != 0) {
perror("unmap fails");
exit(-1);
}
g_free(entry->valid_mapping);
g_free(entry);
}
void xen_invalidate_map_cache_entry(uint8_t *buffer)
{
mapcache_lock();
xen_invalidate_map_cache_entry_unlocked(buffer);
mapcache_unlock();
}
void xen_invalidate_map_cache(void)
{
unsigned long i;
MapCacheRev *reventry;
/* Flush pending AIO before destroying the mapcache */
bdrv_drain_all();
mapcache_lock();
QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
if (!reventry->dma) {
continue;
}
fprintf(stderr, "Locked DMA mapping while invalidating mapcache!"
" "TARGET_FMT_plx" -> %p is present\n",
reventry->paddr_index, reventry->vaddr_req);
}
for (i = 0; i < mapcache->nr_buckets; i++) {
MapCacheEntry *entry = &mapcache->entry[i];
if (entry->vaddr_base == NULL) {
continue;
}
if (entry->lock > 0) {
continue;
}
if (munmap(entry->vaddr_base, entry->size) != 0) {
perror("unmap fails");
exit(-1);
}
entry->paddr_index = 0;
entry->vaddr_base = NULL;
entry->size = 0;
g_free(entry->valid_mapping);
entry->valid_mapping = NULL;
}
mapcache->last_entry = NULL;
mapcache_unlock();
}
static uint8_t *xen_replace_cache_entry_unlocked(hwaddr old_phys_addr,
hwaddr new_phys_addr,
hwaddr size)
{
MapCacheEntry *entry;
hwaddr address_index, address_offset;
hwaddr test_bit_size, cache_size = size;
address_index = old_phys_addr >> MCACHE_BUCKET_SHIFT;
address_offset = old_phys_addr & (MCACHE_BUCKET_SIZE - 1);
assert(size);
/* test_bit_size is always a multiple of XC_PAGE_SIZE */
test_bit_size = size + (old_phys_addr & (XC_PAGE_SIZE - 1));
if (test_bit_size % XC_PAGE_SIZE) {
test_bit_size += XC_PAGE_SIZE - (test_bit_size % XC_PAGE_SIZE);
}
cache_size = size + address_offset;
if (cache_size % MCACHE_BUCKET_SIZE) {
cache_size += MCACHE_BUCKET_SIZE - (cache_size % MCACHE_BUCKET_SIZE);
}
entry = &mapcache->entry[address_index % mapcache->nr_buckets];
while (entry && !(entry->paddr_index == address_index &&
entry->size == cache_size)) {
entry = entry->next;
}
if (!entry) {
DPRINTF("Trying to update an entry for "TARGET_FMT_plx \
"that is not in the mapcache!\n", old_phys_addr);
return NULL;
}
address_index = new_phys_addr >> MCACHE_BUCKET_SHIFT;
address_offset = new_phys_addr & (MCACHE_BUCKET_SIZE - 1);
fprintf(stderr, "Replacing a dummy mapcache entry for "TARGET_FMT_plx \
" with "TARGET_FMT_plx"\n", old_phys_addr, new_phys_addr);
xen_remap_bucket(entry, entry->vaddr_base,
cache_size, address_index, false);
if (!test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping)) {
DPRINTF("Unable to update a mapcache entry for "TARGET_FMT_plx"!\n",
old_phys_addr);
return NULL;
}
return entry->vaddr_base + address_offset;
}
uint8_t *xen_replace_cache_entry(hwaddr old_phys_addr,
hwaddr new_phys_addr,
hwaddr size)
{
uint8_t *p;
mapcache_lock();
p = xen_replace_cache_entry_unlocked(old_phys_addr, new_phys_addr, size);
mapcache_unlock();
return p;
}
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