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

["Michael S. Tsirkin" <mst@redhat.com>]

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.
If it's not it's a guest bug pls just fix it there.


> ---
> v2: Use virtio_is_big_endian()
> v3: Remove "hw/core/cpu.h
> ---
>  hw/audio/virtio-snd.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/audio/virtio-snd.c b/hw/audio/virtio-snd.c
> index c80b58bf5d..939cd78026 100644
> --- a/hw/audio/virtio-snd.c
> +++ b/hw/audio/virtio-snd.c
> @@ -24,7 +24,6 @@
>  #include "trace.h"
>  #include "qapi/error.h"
>  #include "hw/audio/virtio-snd.h"
> -#include "hw/core/cpu.h"
>  
>  #define VIRTIO_SOUND_VM_VERSION 1
>  #define VIRTIO_SOUND_JACK_DEFAULT 0
> @@ -395,13 +394,15 @@ 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 +465,7 @@ 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