This is mostly ok, but there are some small tweaks needed I think.

src/dev/arm/RealView.py (Diff revision 1)

Is this document something people would generally have access to?

src/dev/arm/kmi.hh (Diff revision 1)

These could be an enum, and I don't like the SOMETHING_SOMETHING style. I think it should be KmiCr or KmiCR. These aren't macros, and they shouldn't look like them.

src/dev/arm/kmi.hh (Diff revision 1)

This definitely shouldn't be INTREG_KMI since it's not even a value it's a type. It could be KmiReg.

src/dev/arm/kmi.cc (Diff revision 1)

What do these constants mean? If they don't literally mean the numbers 0, 0x43, etc., then they should be composed symbolically.

src/dev/arm/kmi.cc (Diff revision 1)

Are offsets not allowed within registers? So could I not load the second byte of one? If it's against the rules then ok (maybe an assert?) but if it should work it should work.

src/dev/arm/RealView.py (Diff revision 1)

Yes, it's publicly available on the ARM website. 

src/dev/arm/kmi.hh (Diff revision 1)

Changed.

src/dev/arm/kmi.hh (Diff revision 1)

Changed.

src/dev/arm/kmi.cc (Diff revision 1)

They are the values at reset as listed in the reference manual for the device. 

src/dev/arm/kmi.cc (Diff revision 1)

Yes, what whatever reason you can read the register as 8, 16, ... bits and if you try the smaller size you just get the smaller bits, but the larger read is acceptable as well.