Re: [Qemu-devel] [PATCH] memory: make ram device read/write endian sensitive

[Peter Maydell]

On 21 February 2017 at 18:53, Paolo Bonzini <address@hidden> wrote:
> On 21/02/2017 19:09, Peter Maydell wrote:
>> In this instance I don't understand the patch. The ram_device
>> mem-ops are there to deal with memory regions backed by a
>> lump of RAM, right? Lumps of memory are always the endianness
>> of the host CPU by definition, so DEVICE_NATIVE_ENDIAN and
>> no swapping in the accessors seems like it ought to be the right
>> thing...
>
> DEVICE_NATIVE_ENDIAN is the endianness of the target CPU however.

...I meant 'target CPU' there (at any rate, endianness
of the bus interface between target CPU and its RAM; CPUs
like ARM with runtime configurable endianness do it by swapping
data before it hits the bus interface, conceptually speaking).

Endianness always confuses me, though (I think I understand
it and then I realize I don't; I also have trouble telling
whether I understand it and am discussing it with somebody who
doesn't understand it, or whether I don't understand it and they
do...)

thanks
-- PMM