Chinaunix首页 | 论坛 | 博客
  • 博客访问: 1285938
  • 博文数量: 196
  • 博客积分: 4141
  • 博客等级: 中将
  • 技术积分: 2253
  • 用 户 组: 普通用户
  • 注册时间: 2009-03-21 20:04
文章存档

2019年(31)

2016年(1)

2014年(16)

2011年(8)

2010年(25)

2009年(115)

分类: 虚拟化

2009-03-22 15:04:53

#include <linux/linkage.h>

2 #include <linux/lguest.h>

3 #include <asm/asm-offsets.h>

4 #include <asm/thread_info.h>

5

6 /* FIXME: Once asm/processor-flags.h goes in, include that */

7 #define X86_EFLAGS_IF 0x00000200

8

9 /*

10 * This is where we begin: we have a magic signature which the launcher looks

11 * for. The plan is that the Linux boot protocol will be extended with a

12* "platform type" field which will guide us here from the normal entry point,

13 * but for the moment this suffices. We pass the virtual address of the boot

14 * info to lguest_init().

15 *

16 * We put it in .init.text will be discarded after boot.

17 */

18 .section .init.text, "ax", @progbits

19 .ascii "GenuineLguest"

20 /* Set up initial stack. */

    // #define THREAD_SIZE 8192

    /* union thread_union {

     * struct thread_info thread_info;

     * unsigned long stack[THREAD_SIZE/sizeof(long)];

     * };

     */

21 movl $(init_thread_union+THREAD_SIZE),%esp

22 movl %esi, %eax

23 addl $__PAGE_OFFSET, %eax

24 jmp lguest_init

25

26 /* The templates for inline patching. */

27 #define LGUEST_PATCH(name, insns...) \

28 lgstart_##name: insns; lgend_##name:; \

29 .globl lgstart_##name; .globl lgend_##name

30

31 LGUEST_PATCH(cli, movl $0, lguest_data+LGUEST_DATA_irq_enabled)

32 LGUEST_PATCH(sti, movl $X86_EFLAGS_IF, lguest_data+LGUEST_DATA_irq_enabled)

33 LGUEST_PATCH(popf, movl %eax, lguest_data+LGUEST_DATA_irq_enabled)

34 LGUEST_PATCH(pushf, movl lguest_data+LGUEST_DATA_irq_enabled, %eax)

35

36 .text

37 /* These demark the EIP range where host should never deliver interrupts. */

38 .global lguest_noirq_start

39 .global lguest_noirq_end

40

41 /*

42 * We move eflags word to lguest_data.irq_enabled to restore interrupt state.

43 * For page faults, gpfs and virtual interrupts, the hypervisor has saved

44 * eflags manually, otherwise it was delivered directly and so eflags reflects

45 * the real machine IF state, ie. interrupts on. Since the kernel always dies

46 * if it takes such a trap with interrupts disabled anyway, turning interrupts

47 * back on unconditionally here is OK.

48 */

/* There are two problems with this: firstly, we need to use a register to do

 * the copy and secondly, the whole thing needs to be atomic. The first

 * problem is easy to solve: push %eax on the stack so we can use it, and then

 * restore it at the end just before the real "iret".

 *

 * The second is harder: copying eflags to lguest_data.irq_enabled will turn

 * interrupts on before we

阅读(1610) | 评论(0) | 转发(2) |
给主人留下些什么吧!~~