On Fri, 2013-07-12 at 14:06 -0500, Anthony Liguori wrote: > > In the light of this, I think there should only be one endianness > for > > all memory accesses (which could be changed at runtime), > > We already do this, it's "host native endian".
The simple fact that you used the word "endian" makes it broken here :-) If the guest has done a byte reverse access for example, what you have is not "host native endian" anymore. The simple fact that you use "endian" to describe what you carry around is a source of wrongness and errors. It's misleading and people always get that wrong (I did a bloody talk on the matter at two conferences now and it seems people really don't get what endianness really is about). > > and all > > bridges/devices should ask for "same endianness as parent" or > "reverse > > endianness as parent", but not for big, little, or native > endianness. > > I/O doesn't propagate so there's no way to say something like this. > That's the fundamental problem IMHO. There is no such thing as "endianness of parent" again. This is all wrong. Wrong terminology, wrong concepts. Do not try to use the "endian" attribute on a bus or bridge, it will only confuse things further. Stick to what is the byte order of your transport (much more precise term, ie. which byte is the lowest address within the host variable that carries the access). Ben.
