x86 分頁機制——虛拟位址到實體位址尋址

x86下的分頁機制有一個特點：PAE模式

實體位址擴充，是基于x86 的伺服器的一種功能，它使運作 Windows Server 2003, Enterprise Edition 和 Windows Server 2003，Datacenter Edition 的計算機可以支援4GB 以上實體記憶體。實體位址擴充 (PAE) 允許将最多64GB 的實體記憶體用作正常的4 KB 頁面，并擴充核心能使用的位數以将實體記憶體位址從32擴充到36。

一般情況下都是一頁大小都是4KB，4M為大頁面轉化方式

測試代碼：

int main()

{

char* v1 = "HelloWorld";

printf("%p\r\n", v1);

while (1)

}

return 0;

虛拟位址的意義

13ff6c   =   轉二進制=》    ‭0000000000          0100111111                   111101101100‬

                                          高10位=0             12到21位=13f                         低12位=f6c

                                          PDE索引                  PTE索引                               頁内偏移

PROCESS 866639c8 SessionId: 0 Cid: 0330 Peb: 7ffd7000 ParentCid: 0700

DirBase: 1d50c000 ObjectTable: e1382268 HandleCount: 13.

Image: hello.exe

PROCESS 8619c428 SessionId: 0 Cid: 0f2c Peb: 7ffdd000 ParentCid: 0330

DirBase: 1d78a000 ObjectTable: e21e0270 HandleCount: 38.

Image: conime.exe

kd> !dq 1d50c000

#1d50c000 1d7b7067`1d6f8067 00000000`00000000

#1d50c010 00000000`00000000 00000000`00000000

#1d50c020 00000000`00000000 00000000`00000000

#1d50c030 00000000`00000000 00000000`00000000

#1d50c040 00000000`00000000 00000000`00000000

#1d50c050 00000000`00000000 00000000`00000000

#1d50c060 00000000`00000000 00000000`00000000

#1d50c070 00000000`00000000 00000000`00000000

kd> !dd 1d50c000 PDE索引=0

#1d50c000 1d6f8067 1d7b7067 00000000 00000000

#1d50c010 00000000 00000000 00000000 00000000

#1d50c020 00000000 00000000 00000000 00000000

#1d50c030 00000000 00000000 00000000 00000000

#1d50c040 00000000 00000000 00000000 00000000

#1d50c050 00000000 00000000 00000000 00000000

#1d50c060 00000000 00000000 00000000 00000000

#1d50c070 00000000 00000000 00000000 00000000

kd> !dd 1d6f8000+0x13f*4 PTE索引=13f 每一項4位元組

#1d6f84fc 1d560067 13391025 133d2025 00000000

#1d6f850c 00000000 00000000 00000000 00000000

#1d6f851c 00000000 00000000 00000000 00000000

#1d6f852c 00000000 00000000 00000000 00000000

#1d6f853c 00000000 1d665067 1d666067 1d4a9067

#1d6f854c 1d673067 1d5fb067 1d6c3067 1d688067

#1d6f855c 1d821067 00000080 00000000 00000000

#1d6f856c 00000000 00000000 00000000 00000000

kd> !db 1d560000+f6c   頁内偏移f6c

#1d560f6c 48 65 6c 6c 6f 57 6f 72-6c 64 00 00 00 00 00 00 HelloWorld......

#1d560f7c 00 00 00 00 c0 ff 13 00-d9 87 40 00 01 00 00 00 ..........@.....

#1d560f8c 80 0e 44 00 c0 0d 44 00-39 00 39 00 34 00 34 00 ..D...D.9.9.4.4.

#1d560f9c 00 70 fd 7f 06 00 00 00-04 1d 45 ee 94 ff 13 00 .p........E.....

#1d560fac 9f 2c 58 80 e0 ff 13 00-04 f8 40 00 f8 f3 42 00 .,[email protected].

#1d560fbc 00 00 00 00 f0 ff 13 00-67 70 81 7c 39 00 39 00 ........gp.|9.9.

#1d560fcc 34 00 34 00 00 70 fd 7f-00 ac 19 e2 c8 ff 13 00 4.4..p..........

#1d560fdc a8 6d 34 86 ff ff ff ff-c0 9a 83 7c 70 70 81 7c .m4........|pp.|

 找到HelloWorld。

開啟PAE模式的情況：30~31位變成了PDPTE

相關部落格：http://blog.csdn.net/zfdyq0/article/details/40954721