On 24.01.2014, at 14:09, Paolo Bonzini <pbonz...@redhat.com> wrote: > Il 24/01/2014 01:01, Peter Maydell ha scritto: >>> > >>> > +The 'data' member byte order is host kernel native endianness, >>> > regardless of >>> > +the endianness of the guest, and represents the the value as it would go >>> > on the >>> > +bus in real hardware. The host kernel should always be able to do: >>> > +<type> val = *((<type> *)mmio.data). >> I think this would be better phrased as "The host userspace should always", >> since this documentation is supposed to be telling userspace what the >> kernel's contract with it is, not the kernel keeping notes for itself on >> its own implementation. (It also clarifies what the intention is for the >> obscure and maybe-we'll-never-implement-this case of an LE host >> kernel using a compatibility interface to run the host userspace (QEMU) >> as a BE process which sees the same ABI a BE kernel provides, >> without actually dragging that red herring explicitly into the >> documentation.) > > I agree, and also the first line should mention userspace. > > In PPC I think it's possible or even common to have BE host kernel and LE > host userspace (or perhaps vice versa is the common one).
It was possible on 32bit, but I'm not sure anyone's actively using it :). The thing that was very common (not so much anymore for enterprise distros) is 32-bit user space with 64-bit kernels. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
