unicorn/qemu/include/exec/ramlist.h

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#ifndef RAMLIST_H
#define RAMLIST_H
#include "qemu/queue.h"
#include "qemu/thread.h"
#define DIRTY_MEMORY_CODE 0
#define DIRTY_MEMORY_NUM 1 /* 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 =
* atomic_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;
// Unicorn: unicorn-specific variable to make memory handling less painful
size_t num_blocks;
unsigned long *blocks[];
} DirtyMemoryBlocks;
typedef struct RAMList {
RAMBlock *mru_block;
QLIST_HEAD(, RAMBlock) blocks;
DirtyMemoryBlocks *dirty_memory[DIRTY_MEMORY_NUM];
uint32_t version;
} RAMList;
#endif