Re: [PATCH 2/2] VMX: Reinject real mode exception

[Avi Kivity <avi@qumranet.com>]

Nakajima, Jun wrote:
> On 7/13/2008 8:31:44 AM, Avi Kivity wrote:
>   
>> Avi Kivity wrote:
>>     
>>> Well, xen and bochs do not push an error code for real mode #GP.  I
>>> tried running the attached test program but it doesn't work on real
>>> hardware (it does work on bochs).
>>>
>>>       
>> Jun, perhaps you can clarify? do #GP exceptions in real-mode push an
>> error code?
>>     
>
> Avi,
>
> Exceptions in real-mode do not push an error code in the stack. 

Thanks.  You might consider updating the documentation, for example #DF 
states that an error code of 0 is always pushed.

> In vm86 mode #GP exceptions push an error code, triggering a protected-mode handler in the monitor, as you know. Is it possible that the guest is actually using vm86 mode?
>   

No, it's a real mode guest.  It's emulated using vm86, of course, but it 
thinks it's in real mode.  The question was, when we inject a #GP, #SS, 
or #DF  exception, should we also inject an error code, and according to 
your clarification, the answer is no.

-- 
error compiling committee.c: too many arguments to function