Commit b2a8658e authored by Umesh Deshpande's avatar Umesh Deshpande Committed by Juan Quintela

protect the ramlist with a separate mutex

Add the new mutex that protects shared state between ram_save_live
and the iothread.  If the iothread mutex has to be taken together
with the ramlist mutex, the iothread shall always be _outside_.
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarUmesh Deshpande <udeshpan@redhat.com>
Signed-off-by: default avatarJuan Quintela <quintela@redhat.com>
Reviewed-by: default avatarOrit Wasserman <owasserm@redhat.com>
parent f798b07f
......@@ -528,7 +528,6 @@ static void ram_migration_cancel(void *opaque)
migration_end();
}
static void reset_ram_globals(void)
{
last_block = NULL;
......@@ -547,6 +546,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
bitmap_set(migration_bitmap, 0, ram_pages);
migration_dirty_pages = ram_pages;
qemu_mutex_lock_ramlist();
bytes_transferred = 0;
reset_ram_globals();
......@@ -574,6 +574,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
qemu_put_be64(f, block->length);
}
qemu_mutex_unlock_ramlist();
qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
return 0;
......@@ -588,6 +589,8 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
uint64_t expected_downtime;
MigrationState *s = migrate_get_current();
qemu_mutex_lock_ramlist();
if (ram_list.version != last_version) {
reset_ram_globals();
}
......@@ -636,6 +639,7 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
bwidth = 0.000001;
}
qemu_mutex_unlock_ramlist();
qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
expected_downtime = ram_save_remaining() * TARGET_PAGE_SIZE / bwidth;
......@@ -656,6 +660,8 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
{
migration_bitmap_sync();
qemu_mutex_lock_ramlist();
/* try transferring iterative blocks of memory */
/* flush all remaining blocks regardless of rate limiting */
......@@ -671,6 +677,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
}
migration_end();
qemu_mutex_unlock_ramlist();
qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
return 0;
......
......@@ -213,6 +213,7 @@ bool memory_region_is_unassigned(MemoryRegion *mr)
void cpu_exec_init_all(void)
{
#if !defined(CONFIG_USER_ONLY)
qemu_mutex_init(&ram_list.mutex);
memory_map_init();
io_mem_init();
#endif
......@@ -801,6 +802,16 @@ void qemu_flush_coalesced_mmio_buffer(void)
kvm_flush_coalesced_mmio_buffer();
}
void qemu_mutex_lock_ramlist(void)
{
qemu_mutex_lock(&ram_list.mutex);
}
void qemu_mutex_unlock_ramlist(void)
{
qemu_mutex_unlock(&ram_list.mutex);
}
#if defined(__linux__) && !defined(TARGET_S390X)
#include <sys/vfs.h>
......@@ -982,6 +993,8 @@ void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev)
}
pstrcat(new_block->idstr, sizeof(new_block->idstr), name);
/* This assumes the iothread lock is taken here too. */
qemu_mutex_lock_ramlist();
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
if (block != new_block && !strcmp(block->idstr, new_block->idstr)) {
fprintf(stderr, "RAMBlock \"%s\" already registered, abort!\n",
......@@ -989,6 +1002,7 @@ void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev)
abort();
}
}
qemu_mutex_unlock_ramlist();
}
static int memory_try_enable_merging(void *addr, size_t len)
......@@ -1012,6 +1026,8 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
size = TARGET_PAGE_ALIGN(size);
new_block = g_malloc0(sizeof(*new_block));
/* This assumes the iothread lock is taken here too. */
qemu_mutex_lock_ramlist();
new_block->mr = mr;
new_block->offset = find_ram_offset(size);
if (host) {
......@@ -1057,6 +1073,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
ram_list.mru_block = NULL;
ram_list.version++;
qemu_mutex_unlock_ramlist();
ram_list.phys_dirty = g_realloc(ram_list.phys_dirty,
last_ram_offset() >> TARGET_PAGE_BITS);
......@@ -1082,21 +1099,26 @@ void qemu_ram_free_from_ptr(ram_addr_t addr)
{
RAMBlock *block;
/* This assumes the iothread lock is taken here too. */
qemu_mutex_lock_ramlist();
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
if (addr == block->offset) {
QTAILQ_REMOVE(&ram_list.blocks, block, next);
ram_list.mru_block = NULL;
ram_list.version++;
g_free(block);
return;
break;
}
}
qemu_mutex_unlock_ramlist();
}
void qemu_ram_free(ram_addr_t addr)
{
RAMBlock *block;
/* This assumes the iothread lock is taken here too. */
qemu_mutex_lock_ramlist();
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
if (addr == block->offset) {
QTAILQ_REMOVE(&ram_list.blocks, block, next);
......@@ -1127,9 +1149,10 @@ void qemu_ram_free(ram_addr_t addr)
#endif
}
g_free(block);
return;
break;
}
}
qemu_mutex_unlock_ramlist();
}
......@@ -1207,6 +1230,7 @@ void *qemu_get_ram_ptr(ram_addr_t addr)
{
RAMBlock *block;
/* The list is protected by the iothread lock here. */
block = ram_list.mru_block;
if (block && addr - block->offset < block->length) {
goto found;
......@@ -1246,6 +1270,7 @@ static void *qemu_safe_ram_ptr(ram_addr_t addr)
{
RAMBlock *block;
/* The list is protected by the iothread lock here. */
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
if (addr - block->offset < block->length) {
if (xen_enabled()) {
......
......@@ -22,6 +22,7 @@
#include "qemu-common.h"
#include "qemu/tls.h"
#include "exec/cpu-common.h"
#include "qemu/thread.h"
/* some important defines:
*
......@@ -487,6 +488,9 @@ typedef struct RAMBlock {
ram_addr_t length;
uint32_t flags;
char idstr[256];
/* Reads can take either the iothread or the ramlist lock.
* Writes must take both locks.
*/
QTAILQ_ENTRY(RAMBlock) next;
#if defined(__linux__) && !defined(TARGET_S390X)
int fd;
......@@ -494,8 +498,11 @@ typedef struct RAMBlock {
} RAMBlock;
typedef struct RAMList {
QemuMutex mutex;
/* Protected by the iothread lock. */
uint8_t *phys_dirty;
RAMBlock *mru_block;
/* Protected by the ramlist lock. */
QTAILQ_HEAD(, RAMBlock) blocks;
uint32_t version;
} RAMList;
......@@ -516,6 +523,8 @@ extern int mem_prealloc;
void dump_exec_info(FILE *f, fprintf_function cpu_fprintf);
ram_addr_t last_ram_offset(void);
void qemu_mutex_lock_ramlist(void);
void qemu_mutex_unlock_ramlist(void);
#endif /* !CONFIG_USER_ONLY */
int cpu_memory_rw_debug(CPUArchState *env, target_ulong addr,
......
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