blob: 2ad2a81accfb6fc4ae4534e009d72be9cc558909 [file] [log] [blame]
#ifndef RAMLIST_H
#define RAMLIST_H
#include "qemu/queue.h"
#include "qemu/thread.h"
#include "qemu/rcu.h"
#include "qemu/rcu_queue.h"
typedef struct RAMBlockNotifier RAMBlockNotifier;
#define DIRTY_MEMORY_NUM 3 /* num of dirty bits */
/* The dirty memory bitmap is split into fixed-size blocks to allow growth
* under RCU. The bitmap for a block can be accessed as follows:
* rcu_read_lock();
* DirtyMemoryBlocks *blocks =
* qatomic_rcu_read(&ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION]);
* ram_addr_t idx = (addr >> TARGET_PAGE_BITS) / DIRTY_MEMORY_BLOCK_SIZE;
* unsigned long *block = blocks.blocks[idx];
* ...access block bitmap...
* rcu_read_unlock();
* Remember to check for the end of the block when accessing a range of
* addresses. Move on to the next block if you reach the end.
* Organization into blocks allows dirty memory to grow (but not shrink) under
* RCU. When adding new RAMBlocks requires the dirty memory to grow, a new
* DirtyMemoryBlocks array is allocated with pointers to existing blocks kept
* the same. Other threads can safely access existing blocks while dirty
* memory is being grown. When no threads are using the old DirtyMemoryBlocks
* anymore it is freed by RCU (but the underlying blocks stay because they are
* pointed to from the new DirtyMemoryBlocks).
#define DIRTY_MEMORY_BLOCK_SIZE ((ram_addr_t)256 * 1024 * 8)
typedef struct {
struct rcu_head rcu;
unsigned long *blocks[];
} DirtyMemoryBlocks;
typedef struct RAMList {
QemuMutex mutex;
RAMBlock *mru_block;
/* RCU-enabled, writes protected by the ramlist lock. */
QLIST_HEAD(, RAMBlock) blocks;
DirtyMemoryBlocks *dirty_memory[DIRTY_MEMORY_NUM];
uint32_t version;
QLIST_HEAD(, RAMBlockNotifier) ramblock_notifiers;
} RAMList;
extern RAMList ram_list;
/* Should be holding either ram_list.mutex, or the RCU lock. */
QLIST_FOREACH_RCU(block, &ram_list.blocks, next)
/* Never use the INTERNAL_ version except for defining other macros */
void qemu_mutex_lock_ramlist(void);
void qemu_mutex_unlock_ramlist(void);
struct RAMBlockNotifier {
void (*ram_block_added)(RAMBlockNotifier *n, void *host, size_t size,
size_t max_size);
void (*ram_block_removed)(RAMBlockNotifier *n, void *host, size_t size,
size_t max_size);
void (*ram_block_resized)(RAMBlockNotifier *n, void *host, size_t old_size,
size_t new_size);
QLIST_ENTRY(RAMBlockNotifier) next;
void ram_block_notifier_add(RAMBlockNotifier *n);
void ram_block_notifier_remove(RAMBlockNotifier *n);
void ram_block_notify_add(void *host, size_t size, size_t max_size);
void ram_block_notify_remove(void *host, size_t size, size_t max_size);
void ram_block_notify_resize(void *host, size_t old_size, size_t new_size);
GString *ram_block_format(void);
#endif /* RAMLIST_H */