instrction emulation problem

instrction emulation problem

[strongerwill]

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Hi Keir:
   I am sorry trouble you again. I want to emulate instruction "push %ebp" in Xen. I found the function emulate_privilege_op does not satisfy this requirement.
Then I resort to x86_emulate. I construct the x86_emulate_ctxt and reuse the "ptwr_emulate_ops". 
code like this:

extern const struct x86_emulate_ops ptwr_emulate_ops; 
in do_general_protection {
....
struct x86_emulate_ctxt ctxt; 
ctxt.regs = regs; 
ctxt.force_writeback = 1; // 0 is the same
ctxt.addr_size = 32; 
ctxt.sp_size   = 32; 
ret = x86_emulate(&ctxt, &ptwr_emulate_ops); 
...
}

the error message is:
(XEN) mm.c:5235:d0 ptwr_emulate: bad access (cr2=553a4000, addr=e81b5fac, bytes=4) 


I have another idea, I directly update the stack and change the EIP and ESP
like this:

regs->esp -= 4;
__raw_copy_to_guest((void*)regs->esp, &regs->ebp, sizeof(unsigned int)); 
regs->eip += 1; 

I am not sure it works like this way. Please give me some tips. Thanks

Cheers,

Yueqiang


2010-08-13 



strongerwill 



发件人： Keir Fraser 
发送时间： 2010-08-13  16:52:24 
收件人： xen-devel@lists.xensource.com 
抄送： 
主题： [Xen-devel] FINAL release candidate for Xen 4.0.1 
  
Folks,
The sixth release candidate for 4.0.1 is tagged as 4.0.1-rc6 at
http://xenbits.xen.org/staging/xen-4.0-testing.hg
We expect this to be the final RC, with no changes except for regression
fixes ahead of final release late next week. So please test this RC!
 Thanks,
 Keir
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