We need to keep a local per-cpu copy of the data as other threads may
be running. Currently we can provide insight as to if the access was
IO or not and give the offset into a given device (usually the main
RAMBlock). We store enough information to get details such as the
MemoryRegion which might be useful in later expansions to the API.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>