Re: [PATCH for 4.5 v2 2/2] x86/hvm: Improve "Emulation failed @" error messages

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 29/09/14 09:34, Jan Beulich wrote:
>>>> On 26.09.14 at 18:24, <andrew.cooper3@citrix.com> wrote:
>> @@ -1449,6 +1441,30 @@ struct segment_register *hvmemul_get_seg_reg(
>>      return &hvmemul_ctxt->seg_reg[seg];
>>  }
>>  
>> +static const char *guest_x86_mode_to_str(int mode)
>> +{
>> +    switch ( mode )
>> +    {
>> +    case 0 ... 2: return "16bit";
> I don't really follow why you dropped the real and vm86 mode
> special casing here (nor do I think ???_guest_x86_mode() is
> producing insufficient detail for the purposes here or elsewhere).
>
> Jan
>

I specifically want to avoid having specifics like "Real" and "v86"
along side more generic terms such as "16bit", because I can see even
myself as the author getting confused in the future.

One option would be to borrow the terminology from
http://sandpile.org/x86/mode.htm which is unambiguous, and provides
rather more information than just how to decode the instructions. 
Unfortunately, ???_guest_x86_mode() is insufficiently expressive to
express this complete set.

Therefore, I opted for the other extreme to avoid having a mix of
information returned from guest_x86_mode_to_str().

~Andrew