Re: [PATCH] Enable memory mapped TPR shadow(FlexPriority)

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Yang, Sheng wrote:
> Avi Kivity wrote:
>   
>> Yang, Sheng wrote:
>>     
>>> Another comment: I forgot if I answer the question on why eip should
>>>       
> move
>   
>>> backward. I did it because some instruction like "mov" will move eip
>>>       
> to
>   
>>> skip some dst/src operand when executing, so eip should be kept for
>>> consistency. 
>>>
>>>       
>> I think you're talking about
>>
>>     
>>>     case 0xa0 ... 0xa1:    /* mov */
>>>         c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
>>>         c->dst.val = c->src.val;
>>>         /* skip src displacement */
>>>         c->eip += c->ad_bytes;
>>>         break;
>>>       
>> ?
>>
>> If so, instead of skipping, we can fetch the address here.
>>
>> It's been annoying me for a long time; it causes a dependency on cr2
>> which we don't have in real mode (and with FlexPriority), and which is
>> broken anyway because cr2 points at the wrong address during a page
>> fault on the second page of a misaligned cross-page access.
>>     
>
> Yeah, like that. But I don't think only "mov" has memory operand, so
> fetch
> address in some determined place is better than inside every instruction
> executing 
> code. 
>
>   

I think mov is the only instruction that uses absolute addresses without 
modrm encoding.  And modrm encoding is implemented correctly for a long 
time.


> Another thing, if we can use physical address as supplement of cr2 in
> emulate_instrcutions,
> that will be better. Any suggestion?
>   

Sorry, I don't understand the question.

I'd like to see cr2 completely removed from x86_emulate.c.


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


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