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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-hvm-common.h"
#include "hw/xen/xen_native.h"
#include "qemu/bitmap.h"
#include "sysemu/runstate.h"
#include "sysemu/xen-mapcache.h"
#include "trace.h"
#include <xenevtchn.h>
#include <xengnttab.h>
#if HOST_LONG_BITS == 32
# define MCACHE_MAX_SIZE (1UL<<31) /* 2GB Cap */
#else
# define MCACHE_MAX_SIZE (1UL<<35) /* 32GB Cap */
#endif
/* 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)
#define XEN_MAPCACHE_ENTRY_GRANT (1 << 1)
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 bucket_shift;
unsigned long bucket_size;
phys_offset_to_gaddr_t phys_offset_to_gaddr;
QemuMutex lock;
void *opaque;
} MapCache;
static MapCache *mapcache;
static MapCache *mapcache_grants;
static xengnttab_handle *xen_region_gnttabdev;
static inline void mapcache_lock(MapCache *mc)
{
qemu_mutex_lock(&mc->lock);
}
static inline void mapcache_unlock(MapCache *mc)
{
qemu_mutex_unlock(&mc->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;
}
static MapCache *xen_map_cache_init_single(phys_offset_to_gaddr_t f,
void *opaque,
unsigned int bucket_shift,
unsigned long max_size)
{
unsigned long size;
MapCache *mc;
assert(bucket_shift >= XC_PAGE_SHIFT);
mc = g_new0(MapCache, 1);
mc->phys_offset_to_gaddr = f;
mc->opaque = opaque;
qemu_mutex_init(&mc->lock);
QTAILQ_INIT(&mc->locked_entries);
mc->bucket_shift = bucket_shift;
mc->bucket_size = 1UL << bucket_shift;
mc->max_mcache_size = max_size;
mc->nr_buckets =
(((mc->max_mcache_size >> XC_PAGE_SHIFT) +
(1UL << (bucket_shift - XC_PAGE_SHIFT)) - 1) >>
(bucket_shift - XC_PAGE_SHIFT));
size = mc->nr_buckets * sizeof(MapCacheEntry);
size = (size + XC_PAGE_SIZE - 1) & ~(XC_PAGE_SIZE - 1);
trace_xen_map_cache_init(mc->nr_buckets, size);
mc->entry = g_malloc0(size);
return mc;
}
void xen_map_cache_init(phys_offset_to_gaddr_t f, void *opaque)
{
struct rlimit rlimit_as;
unsigned long max_mcache_size;
unsigned int bucket_shift;
xen_region_gnttabdev = xengnttab_open(NULL, 0);
if (xen_region_gnttabdev == NULL) {
error_report("mapcache: Failed to open gnttab device");
exit(EXIT_FAILURE);
}
if (HOST_LONG_BITS == 32) {
bucket_shift = 16;
} else {
bucket_shift = 20;
}
if (geteuid() == 0) {
rlimit_as.rlim_cur = RLIM_INFINITY;
rlimit_as.rlim_max = RLIM_INFINITY;
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) {
max_mcache_size = rlimit_as.rlim_max - NON_MCACHE_MEMORY_SIZE;
} else {
max_mcache_size = MCACHE_MAX_SIZE;
}
}
mapcache = xen_map_cache_init_single(f, opaque,
bucket_shift,
max_mcache_size);
/*
* Grant mappings must use XC_PAGE_SIZE granularity since we can't
* map anything beyond the number of pages granted to us.
*/
mapcache_grants = xen_map_cache_init_single(f, opaque,
XC_PAGE_SHIFT,
max_mcache_size);
setrlimit(RLIMIT_AS, &rlimit_as);
}
static void xen_remap_bucket(MapCache *mc,
MapCacheEntry *entry,
void *vaddr,
hwaddr size,
hwaddr address_index,
bool dummy,
bool grant,
bool is_write,
ram_addr_t ram_offset)
{
uint8_t *vaddr_base;
g_autofree uint32_t *refs = NULL;
g_autofree xen_pfn_t *pfns = NULL;
g_autofree int *err;
unsigned int i;
hwaddr nb_pfn = size >> XC_PAGE_SHIFT;
trace_xen_remap_bucket(address_index);
if (grant) {
refs = g_new0(uint32_t, nb_pfn);
} else {
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;
if (grant) {
hwaddr grant_base = address_index - (ram_offset >> XC_PAGE_SHIFT);
for (i = 0; i < nb_pfn; i++) {
refs[i] = grant_base + i;
}
} else {
for (i = 0; i < nb_pfn; i++) {
pfns[i] = (address_index << (mc->bucket_shift - XC_PAGE_SHIFT)) + i;
}
}
entry->flags &= ~XEN_MAPCACHE_ENTRY_GRANT;
if (!dummy) {
if (grant) {
int prot = PROT_READ;
if (is_write) {
prot |= PROT_WRITE;
}
entry->flags |= XEN_MAPCACHE_ENTRY_GRANT;
assert(vaddr == NULL);
vaddr_base = xengnttab_map_domain_grant_refs(xen_region_gnttabdev,
nb_pfn,
xen_domid, refs,
prot);
} else {
/*
* If the caller has requested the mapping at a specific address use
* MAP_FIXED to make sure it's honored.
*
* We don't yet support upgrading mappings from RO to RW, to handle
* models using ordinary address_space_rw(), foreign mappings ignore
* is_write and are always mapped RW.
*/
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(grant ? "xengnttab_map_domain_grant_refs"
: "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);
}
}
}
static uint8_t *xen_map_cache_unlocked(MapCache *mc,
hwaddr phys_addr, hwaddr size,
ram_addr_t ram_offset,
uint8_t lock, bool dma,
bool grant, bool is_write)
{
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 >> mc->bucket_shift;
address_offset = phys_addr & (mc->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 (mc->last_entry != NULL &&
mc->last_entry->paddr_index == address_index &&
!lock && !size &&
test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
mc->last_entry->valid_mapping)) {
trace_xen_map_cache_return(
mc->last_entry->vaddr_base + address_offset
);
return mc->last_entry->vaddr_base + address_offset;
}
/* size is always a multiple of mc->bucket_size */
if (size) {
cache_size = size + address_offset;
if (cache_size % mc->bucket_size) {
cache_size += mc->bucket_size - (cache_size % mc->bucket_size);
}
} else {
cache_size = mc->bucket_size;
}
entry = &mc->entry[address_index % mc->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(mc, entry, NULL, cache_size, address_index, dummy,
grant, is_write, ram_offset);
} 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(mc, entry, NULL, cache_size, address_index, dummy,
grant, is_write, ram_offset);
}
}
if(!test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping)) {
mc->last_entry = NULL;
#ifdef XEN_COMPAT_PHYSMAP
if (!translated && mc->phys_offset_to_gaddr) {
phys_addr = mc->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;
}
mc->last_entry = entry;
if (lock) {
MapCacheRev *reventry = g_new0(MapCacheRev, 1);
entry->lock++;
if (entry->lock == 0) {
error_report("mapcache entry lock overflow: "HWADDR_FMT_plx" -> %p",
entry->paddr_index, entry->vaddr_base);
abort();
}
reventry->dma = dma;
reventry->vaddr_req = mc->last_entry->vaddr_base + address_offset;
reventry->paddr_index = mc->last_entry->paddr_index;
reventry->size = entry->size;
QTAILQ_INSERT_HEAD(&mc->locked_entries, reventry, next);
}
trace_xen_map_cache_return(
mc->last_entry->vaddr_base + address_offset
);
return mc->last_entry->vaddr_base + address_offset;
}
uint8_t *xen_map_cache(MemoryRegion *mr,
hwaddr phys_addr, hwaddr size,
ram_addr_t ram_addr_offset,
uint8_t lock, bool dma,
bool is_write)
{
bool grant = xen_mr_is_grants(mr);
MapCache *mc = grant ? mapcache_grants : mapcache;
uint8_t *p;
if (grant && !lock) {
/*
* Grants are only supported via address_space_map(). Anything
* else is considered a user/guest error.
*
* QEMU generally doesn't expect these mappings to ever fail, so
* if this happens we report an error message and abort().
*/
error_report("Tried to access a grant reference without mapping it.");
abort();
}
mapcache_lock(mc);
p = xen_map_cache_unlocked(mc, phys_addr, size, ram_addr_offset,
lock, dma, grant, is_write);
mapcache_unlock(mc);
return p;
}
static ram_addr_t xen_ram_addr_from_mapcache_single(MapCache *mc, void *ptr)
{
MapCacheEntry *entry = NULL;
MapCacheRev *reventry;
hwaddr paddr_index;
hwaddr size;
ram_addr_t raddr;
int found = 0;
mapcache_lock(mc);
QTAILQ_FOREACH(reventry, &mc->locked_entries, next) {
if (reventry->vaddr_req == ptr) {
paddr_index = reventry->paddr_index;
size = reventry->size;
found = 1;
break;
}
}
if (!found) {
trace_xen_ram_addr_from_mapcache_not_found(ptr);
mapcache_unlock(mc);
return RAM_ADDR_INVALID;
}
entry = &mc->entry[paddr_index % mc->nr_buckets];
while (entry && (entry->paddr_index != paddr_index || entry->size != size)) {
entry = entry->next;
}
if (!entry) {
trace_xen_ram_addr_from_mapcache_not_in_cache(ptr);
raddr = RAM_ADDR_INVALID;
} else {
raddr = (reventry->paddr_index << mc->bucket_shift) +
((unsigned long) ptr - (unsigned long) entry->vaddr_base);
}
mapcache_unlock(mc);
return raddr;
}
ram_addr_t xen_ram_addr_from_mapcache(void *ptr)
{
ram_addr_t addr;
addr = xen_ram_addr_from_mapcache_single(mapcache, ptr);
if (addr == RAM_ADDR_INVALID) {
addr = xen_ram_addr_from_mapcache_single(mapcache_grants, ptr);
}
return addr;
}
static void xen_invalidate_map_cache_entry_unlocked(MapCache *mc,
uint8_t *buffer)
{
MapCacheEntry *entry = NULL, *pentry = NULL;
MapCacheRev *reventry;
hwaddr paddr_index;
hwaddr size;
int found = 0;
int rc;
QTAILQ_FOREACH(reventry, &mc->locked_entries, next) {
if (reventry->vaddr_req == buffer) {
paddr_index = reventry->paddr_index;
size = reventry->size;
found = 1;
break;
}
}
if (!found) {
trace_xen_invalidate_map_cache_entry_unlocked_not_found(buffer);
QTAILQ_FOREACH(reventry, &mc->locked_entries, next) {
trace_xen_invalidate_map_cache_entry_unlocked_found(
reventry->paddr_index,
reventry->vaddr_req
);
}
return;
}
QTAILQ_REMOVE(&mc->locked_entries, reventry, next);
g_free(reventry);
if (mc->last_entry != NULL &&
mc->last_entry->paddr_index == paddr_index) {
mc->last_entry = NULL;
}
entry = &mc->entry[paddr_index % mc->nr_buckets];
while (entry && (entry->paddr_index != paddr_index || entry->size != size)) {
pentry = entry;
entry = entry->next;
}
if (!entry) {
trace_xen_invalidate_map_cache_entry_unlocked_miss(buffer);
return;
}
entry->lock--;
if (entry->lock > 0) {
return;
}
ram_block_notify_remove(entry->vaddr_base, entry->size, entry->size);
if (entry->flags & XEN_MAPCACHE_ENTRY_GRANT) {
rc = xengnttab_unmap(xen_region_gnttabdev, entry->vaddr_base,
entry->size >> mc->bucket_shift);
} else {
rc = munmap(entry->vaddr_base, entry->size);
}
if (rc) {
perror("unmap fails");
exit(-1);
}
g_free(entry->valid_mapping);
if (pentry) {
pentry->next = entry->next;
g_free(entry);
} else {
memset(entry, 0, sizeof *entry);
}
}
typedef struct XenMapCacheData {
Coroutine *co;
uint8_t *buffer;
} XenMapCacheData;
static void xen_invalidate_map_cache_entry_single(MapCache *mc, uint8_t *buffer)
{
mapcache_lock(mc);
xen_invalidate_map_cache_entry_unlocked(mc, buffer);
mapcache_unlock(mc);
}
static void xen_invalidate_map_cache_entry_all(uint8_t *buffer)
{
xen_invalidate_map_cache_entry_single(mapcache, buffer);
xen_invalidate_map_cache_entry_single(mapcache_grants, buffer);
}
static void xen_invalidate_map_cache_entry_bh(void *opaque)
{
XenMapCacheData *data = opaque;
xen_invalidate_map_cache_entry_all(data->buffer);
aio_co_wake(data->co);
}
void coroutine_mixed_fn xen_invalidate_map_cache_entry(uint8_t *buffer)
{
if (qemu_in_coroutine()) {
XenMapCacheData data = {
.co = qemu_coroutine_self(),
.buffer = buffer,
};
aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
xen_invalidate_map_cache_entry_bh, &data);
qemu_coroutine_yield();
} else {
xen_invalidate_map_cache_entry_all(buffer);
}
}
static void xen_invalidate_map_cache_single(MapCache *mc)
{
unsigned long i;
MapCacheRev *reventry;
mapcache_lock(mc);
QTAILQ_FOREACH(reventry, &mc->locked_entries, next) {
if (!reventry->dma) {
continue;
}
trace_xen_invalidate_map_cache(reventry->paddr_index,
reventry->vaddr_req);
}
for (i = 0; i < mc->nr_buckets; i++) {
MapCacheEntry *entry = &mc->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;
}
mc->last_entry = NULL;
mapcache_unlock(mc);
}
void xen_invalidate_map_cache(void)
{
/* Flush pending AIO before destroying the mapcache */
bdrv_drain_all();
xen_invalidate_map_cache_single(mapcache);
xen_invalidate_map_cache_single(mapcache_grants);
}
static uint8_t *xen_replace_cache_entry_unlocked(MapCache *mc,
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 >> mc->bucket_shift;
address_offset = old_phys_addr & (mc->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 % mc->bucket_size) {
cache_size += mc->bucket_size - (cache_size % mc->bucket_size);
}
entry = &mc->entry[address_index % mc->nr_buckets];
while (entry && !(entry->paddr_index == address_index &&
entry->size == cache_size)) {
entry = entry->next;
}
if (!entry) {
trace_xen_replace_cache_entry_unlocked(old_phys_addr);
return NULL;
}
assert((entry->flags & XEN_MAPCACHE_ENTRY_GRANT) == 0);
address_index = new_phys_addr >> mc->bucket_shift;
address_offset = new_phys_addr & (mc->bucket_size - 1);
trace_xen_replace_cache_entry_dummy(old_phys_addr, new_phys_addr);
xen_remap_bucket(mc, entry, entry->vaddr_base,
cache_size, address_index, false,
false, false, old_phys_addr);
if (!test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping)) {
trace_xen_replace_cache_entry_unlocked_could_not_update_entry(
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(mapcache);
p = xen_replace_cache_entry_unlocked(mapcache, old_phys_addr,
new_phys_addr, size);
mapcache_unlock(mapcache);
return p;
}
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