Re: [Xen-devel] [PATCH] add mov instruction decoder in protected toreal mode in vmxassist

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

>>> "Li, Xin B" <xin.b.li@xxxxxxxxx> 02.07.07 18:03 >>>
>decode mov instruction in protected to real mode in vmxassist.
>Also some clean up.
>
>Signed-off-by: Xin Li <xin.b.li@xxxxxxxxx>

This is what I really don't like about decoder adjustments: Even when changes
for a certain instruction type are found necessary, no care is taken that 
similar
instructions are also updated/added. In this case, for instance, you add the
register destination/source case for opcode 0x89/0x8B, but the same adjustments
aren't made for opcode 0x88/0x8A. This is calling for future problems, as much
as e.g. the absence of emulation of opcode 0xC7 despite present emulation
of 0xC6. I'm not going to continue, but I suppose you get my point.

Also, how come that the mode/address size conditions are different for
0x88/0x8A versus 0x89/0x8B (they were identical so far for 0x88, 0x8A, and
0x8B, with some extra code for 0x89)?

Jan


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