Re: [PATCH v2] hw/audio/virtio-snd: Use device endianness instead of target one

[Manos Pitsidianakis <manos.pitsidianakis@linaro.org>]

On Mon, 22 Apr 2024 16:13, Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
>Since VirtIO devices can change endianness at runtime,
>we need to use the device endianness, not the target
>one.

Hey Philippe, can you clarify what do you mean by they can change 
endianness at runtime?

The target's one is used because that's the one it will be using to do 
I/O with its kernel's audio interface.





>
>Cc: qemu-stable@nongnu.org
>Fixes: eb9ad377bb ("virtio-sound: handle control messages and streams")
>Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>---
> hw/audio/virtio-snd.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
>diff --git a/hw/audio/virtio-snd.c b/hw/audio/virtio-snd.c
>index c80b58bf5d..82c5647660 100644
>--- a/hw/audio/virtio-snd.c
>+++ b/hw/audio/virtio-snd.c
>@@ -395,13 +395,15 @@ static uint32_t virtio_snd_get_qemu_freq(uint32_t rate)
>  * Get QEMU Audiosystem compatible audsettings from virtio based pcm stream
>  * params.
>  */
>-static void virtio_snd_get_qemu_audsettings(audsettings *as,
>+static void virtio_snd_get_qemu_audsettings(VirtIOSound *s, audsettings *as,
>                                             virtio_snd_pcm_set_params *params)
> {
>+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
>+
>     as->nchannels = MIN(AUDIO_MAX_CHANNELS, params->channels);
>     as->fmt = virtio_snd_get_qemu_format(params->format);
>     as->freq = virtio_snd_get_qemu_freq(params->rate);
>-    as->endianness = target_words_bigendian() ? 1 : 0;
>+    as->endianness = virtio_is_big_endian(vdev) ? 1 : 0;
> }
> 
> /*
>@@ -464,7 +466,7 @@ static uint32_t virtio_snd_pcm_prepare(VirtIOSound *s, uint32_t stream_id)
>         s->pcm->streams[stream_id] = stream;
>     }
> 
>-    virtio_snd_get_qemu_audsettings(&as, params);
>+    virtio_snd_get_qemu_audsettings(s, &as, params);
>     stream->info.direction = stream_id < s->snd_conf.streams / 2 +
>         (s->snd_conf.streams & 1) ? VIRTIO_SND_D_OUTPUT : VIRTIO_SND_D_INPUT;
>     stream->info.hdr.hda_fn_nid = VIRTIO_SOUND_HDA_FN_NID;
>-- 
>2.41.0
>