Re: [PATCH v3] hw/audio/virtio-snd: Use device endianness instead of target one

[Philippe Mathieu-Daudé]

On 23/4/24 11:18, Manos Pitsidianakis wrote:
> On Tue, 23 Apr 2024 at 11:47, Manos Pitsidianakis
> <manos.pitsidianakis@linaro.org> wrote:
> > On Tue, 23 Apr 2024 at 00:11, Michael S. Tsirkin <mst@redhat.com> wrote:
> > > On Mon, Apr 22, 2024 at 11:07:21PM +0200, Philippe Mathieu-Daudé wrote:
> > > > On 22/4/24 23:02, Michael S. Tsirkin wrote:
> > > > > On Mon, Apr 22, 2024 at 04:20:56PM +0200, Philippe Mathieu-Daudé wrote:
> > > > > > Since VirtIO devices can change endianness at runtime,
> > > > > > we need to use the device endianness, not the target
> > > > > > one.
> > > > > >
> > > > > > Cc: qemu-stable@nongnu.org
> > > > > > Fixes: eb9ad377bb ("virtio-sound: handle control messages and streams")
> > > > > > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> > > > >
> > > > >
> > > > >
> > > > > This is all completely bogus. Virtio SND is from Virtio 1.0 only.
> > > > > It is unconditionally little endian.
> >
> >
> > This part of the code is for PCM frames (raw bytes), not virtio spec
> > fields (which indeed must be LE in modern VIRTIO).
>
> Thought a little more about it. We should keep the target's endianness
> here, if it's mutable then we should query the machine the device is
> attached to somehow. the virtio device should never change endianness
> like Michael says since it's not legacy.

Grr. So as Richard suggested, this need to be pass as a device
property then.
(https://lore.kernel.org/qemu-devel/ed134c9d-6e6f-465b-900f-e39ca4e09876@linaro.org/)