Re: [kvm-devel] [PATCH] (big) real mode emulation - initialization fixes

[Avi K. <av...@qu...>]

Nitin A Kamble wrote:
> On Fri, 2007-09-14 at 10:08 -0700, Avi Kivity wrote:
>   
>> This seems like it is papering over other bugs.  Some instructions use
>> src.val or dst.val without having decoded the src or dst operand.
>>
>> Which instructions are these?  Can we fix them instead?
>>     
>
>   Instructions using 8bit operands such as al, ah are affected.
> Especially utilizing signed operands. By not using this initialization
> these operands are getting wrong value from remaining stale bits.
>
>   

I see.  SrcMem decode does ->read_emulated() into src.val, leaving stale
bits.  I agree your patch is the best way to fix it.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.