On Mon, 13 May 2019 at 16:31, Dave Martin <dave.mar...@arm.com> wrote: > > On Mon, May 13, 2019 at 02:55:01PM +0100, Andrew Jones wrote: > > QEMU keeps its 128-bit and larger words in the same order (least > > significant word first) for both host endian types. We need to > > do word swapping every time we set/get them to/from KVM. > > I'm not sure whether this is appropriate here, though it depends on > what QEMU does with the data.
The layout is optimised for TCG emulation to be able to work with it, I think (rth would have the definite reason, though). > Something non-obvious to be aware of: > > As exposed through the signal frame and the KVM ABI, the memory > representation of an SVE reg is invariant with respect to the > endianness. Yes; we handle this conversion as we write out the signal frame: https://github.com/qemu/qemu/blob/master/linux-user/aarch64/signal.c#L184 thanks -- PMM
