Re: [PATCH v8 05/12] virtio-sound: handle VIRTIO_SND_R_PCM_INFO request

[Philippe Mathieu-Daudé]

On 28/8/23 21:55, Emmanouil Pitsidianakis wrote:
> Respond to the VIRTIO_SND_R_PCM_INFO control request with the parameters
> of each requested PCM stream.
>
> Based-on: 
> https://github.com/OpenSynergy/qemu/commit/5a2f350eec5d157b90d9c7b40a8e603f4da92471
> Signed-off-by: Igor Skalkin <Igor.Skalkin@opensynergy.com>
> Signed-off-by: Anton Yakovlev <Anton.Yakovlev@opensynergy.com>
> Signed-off-by: Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org>
> ---
>   hw/virtio/trace-events |  1 +
>   hw/virtio/virtio-snd.c | 76 ++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 77 insertions(+)


> +/*
> + * Handle the VIRTIO_SND_R_PCM_INFO request.
> + * The function writes the info structs to the request element.
> + *
> + * @s: VirtIOSound device
> + * @cmd: The request command queue element from VirtIOSound cmdq field
> + */
> +static void virtio_snd_handle_pcm_info(VirtIOSound *s,
> +                                       virtio_snd_ctrl_command *cmd)
> +{
> +    virtio_snd_query_info req;
> +    VirtIOSoundPCMStream *stream = NULL;
> +    g_autofree virtio_snd_pcm_info *pcm_info = NULL;
> +    size_t sz = iov_to_buf(cmd->elem->out_sg,
> +                           cmd->elem->out_num,
> +                           0,
> +                           &req,
> +                           sizeof(req));
> +    if (sz != sizeof(virtio_snd_query_info)) {
> +        cmd->resp.code = VIRTIO_SND_S_BAD_MSG;
> +        return;
> +    }
> +
> +    if (iov_size(cmd->elem->in_sg, cmd->elem->in_num) <
> +        sizeof(virtio_snd_hdr) + req.size * req.count) {
> +        error_report("pcm info: buffer too small, got: %zu, needed: %zu",
> +                iov_size(cmd->elem->in_sg, cmd->elem->in_num),
> +                sizeof(virtio_snd_pcm_info));
> +        cmd->resp.code = VIRTIO_SND_S_BAD_MSG;
> +        return;
> +    }
> +
> +    pcm_info = g_new0(virtio_snd_pcm_info, req.count);
> +    for (uint32_t i = req.start_id; i < req.start_id + req.count; i++) {

Starting from req.start_id seems to increase this code complexity.

> +        trace_virtio_snd_handle_pcm_info(i);
> +        stream = virtio_snd_pcm_get_stream(s, i);
> +
> +        if (!stream) {
> +            error_report("Invalid stream id: %"PRIu32, i);
> +            cmd->resp.code = VIRTIO_SND_S_BAD_MSG;
> +            return;
> +        }
> +
> +        pcm_info[i - req.start_id].hdr.hda_fn_nid = 
> stream->info.hdr.hda_fn_nid;
> +        pcm_info[i - req.start_id].features = stream->features;
> +        pcm_info[i - req.start_id].formats = stream->formats;
> +        pcm_info[i - req.start_id].rates = stream->rates;
> +        pcm_info[i - req.start_id].direction = stream->direction;
> +        pcm_info[i - req.start_id].channels_min = stream->channels_min;
> +        pcm_info[i - req.start_id].channels_max = stream->channels_max;
> +    }
> +
> +    cmd->resp.code = VIRTIO_SND_S_OK;
> +
> +    iov_from_buf(cmd->elem->in_sg,
> +                 cmd->elem->in_num,
> +                 sizeof(virtio_snd_hdr),
> +                 pcm_info,
> +                 sizeof(virtio_snd_pcm_info) * req.count);
> +}