Re: [PATCH v3 5/9] hw/audio/virtio-sound: add stream state variable

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

On Mon, Jun 29, 2026 at 10:58:32AM +0300, Manos Pitsidianakis wrote:
> On Fri, 26 Jun 2026 15:35, Alexander Mikhalitsyn <alexander@mihalicyn.com> wrote:
> > From: Volker Rümelin <vr_qemu@t-online.de>
> > 
> > So far, only rudimentary checks have been made to ensure that
> > the guest only performs state transitions permitted in
> > virtio-v1.2-csd01 5.14.6.6.1 PCM Command Lifecycle. Add a state
> > variable per audio stream and check all state transitions.
> 
> 
> This was on purpose: 5.14.6.6.1 is not a Device Requirement / normative
> statement. (In my opinion it should have been).

It's easy to add them - even strong ones (MUST) if it's clear from the description that this
was always the intent, and no reasonable implementation would
do anything else. 

If not we can add weak ones (SHOULD).


> I do not oppose keeping the state though, I chose to do it in the Rust
> implementation (vhost-device-sound) after I wrote this one as well. It makes
> sense. But please update the commit message to say that this is not about
> spec compliance, but simply doing a sanity check following the PCM Command
> Lifecycle section.
> 
> 
> > 
> > Because only permitted state transitions are possible, only one
> > copy of the audio stream parameters is required and these do not
> > need to be initialised with default values.
> > 
> > The state variable will also make it easier to restore the audio
> > stream after migration.
> > 
> > Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
> > [AM: there were too many conflicts, I did `git checkout --ours -- <.>`
> >     and then reimplemented the patch idea
> > /AM]
> > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@futurfusion.io>
> > ---
> > v3:
> > 	- explicitly call virtio_snd_pcm_close() from unrealize
> > 	- remove a call to virtio_snd_pcm_flush() from virtio_snd_pcm_close()
> > 	[ ^ this was my rebase mistake ]
> > ---
> > hw/audio/virtio-snd.c         | 196 +++++++++++++++++++---------------
> > include/hw/audio/virtio-snd.h |  18 +---
> > 2 files changed, 109 insertions(+), 105 deletions(-)
> > 
> > diff --git a/hw/audio/virtio-snd.c b/hw/audio/virtio-snd.c
> > index 300ba13ffeb..68d737478f5 100644
> > --- a/hw/audio/virtio-snd.c
> > +++ b/hw/audio/virtio-snd.c
> > @@ -30,11 +30,30 @@
> > #define VIRTIO_SOUND_CHMAP_DEFAULT 0
> > #define VIRTIO_SOUND_HDA_FN_NID 0
> > 
> > +#define VSND_PCMSTREAM_STATE_F_PARAMS_SET  0x10000
> > +#define VSND_PCMSTREAM_STATE_F_PREPARED    0x20000
> > +#define VSND_PCMSTREAM_STATE_F_ACTIVE      0x40000
> > +
> > +#define VSND_PCMSTREAM_STATE_UNINITIALIZED 0
> > +#define VSND_PCMSTREAM_STATE_PARAMS_SET    (1 \
> > +                                           | VSND_PCMSTREAM_STATE_F_PARAMS_SET)
> > +#define VSND_PCMSTREAM_STATE_PREPARED      (2 \
> > +                                           | VSND_PCMSTREAM_STATE_F_PARAMS_SET \
> > +                                           | VSND_PCMSTREAM_STATE_F_PREPARED)
> > +#define VSND_PCMSTREAM_STATE_STARTED       (4 \
> > +                                           | VSND_PCMSTREAM_STATE_F_PARAMS_SET \
> > +                                           | VSND_PCMSTREAM_STATE_F_PREPARED \
> > +                                           | VSND_PCMSTREAM_STATE_F_ACTIVE)
> > +#define VSND_PCMSTREAM_STATE_STOPPED       (6 \
> > +                                           | VSND_PCMSTREAM_STATE_F_PARAMS_SET \
> > +                                           | VSND_PCMSTREAM_STATE_F_PREPARED)
> > +#define VSND_PCMSTREAM_STATE_RELEASED      (7 \
> > +                                           | VSND_PCMSTREAM_STATE_F_PARAMS_SET)
> 
> Are the VSND_PCMSTREAM_STATE_F_* really needed? Seems excessive.
> 
> I'd do: (did not type check/compile)
> 
> + enum virtio_snd_pcm_state {
> +   VIRTIO_SND_PCM_STATE_UNINIT = 0,
> +   VIRTIO_SND_PCM_STATE_PARAMS_SET,
> +   VIRTIO_SND_PCM_STATE_PREPARED,
> +   VIRTIO_SND_PCM_STATE_STARTED,
> +   VIRTIO_SND_PCM_STATE_STOPPED,
> +   VIRTIO_SND_PCM_STATE_RELEASED,
> + }
> 
> Maybe even write a "method" "macro" for preparedness:
> 
> +
> + static inline bool virtio_snd_pcm_state_prepared(virtio_snd_pcm_state s) {
> + return s > VIRTIO_SND_PCM_STATE_PARAMS_SET && s <
> VIRTIO_SND_PCM_STATE_RELEASED
> + }
> 
> And "active" flag bit is only in STARTED state, so just check for equality.
> 
> This is not a hard request, but it seems simpler to me and would prefer it.
> 
> > +
> > static void virtio_snd_pcm_out_cb(void *data, int available);
> > static void virtio_snd_process_cmdq(VirtIOSound *s);
> > static void virtio_snd_pcm_flush(VirtIOSoundPCMStream *stream);
> > static void virtio_snd_pcm_in_cb(void *data, int available);
> > -static void virtio_snd_unrealize(DeviceState *dev);
> > 
> > static uint32_t supported_formats = BIT(VIRTIO_SND_PCM_FMT_S8)
> >                                   | BIT(VIRTIO_SND_PCM_FMT_U8)
> > @@ -129,7 +148,7 @@ static VirtIOSoundPCMStream *virtio_snd_pcm_get_stream(VirtIOSound *s,
> >                                                        uint32_t stream_id)
> > {
> >     return stream_id >= s->snd_conf.streams ? NULL :
> > -        s->pcm.streams[stream_id];
> > +        &s->streams[stream_id];
> > }
> > 
> > /*
> > @@ -141,8 +160,8 @@ static VirtIOSoundPCMStream *virtio_snd_pcm_get_stream(VirtIOSound *s,
> > static virtio_snd_pcm_set_params *virtio_snd_pcm_get_params(VirtIOSound *s,
> >                                                             uint32_t stream_id)
> > {
> > -    return stream_id >= s->snd_conf.streams ? NULL
> > -        : &s->pcm.pcm_params[stream_id];
> > +    return stream_id >= s->snd_conf.streams ? NULL :
> > +        &s->streams[stream_id].params;
> > }
> > 
> > /*
> > @@ -245,11 +264,10 @@ static void virtio_snd_handle_pcm_info(VirtIOSound *s,
> > 
> > /*
> >  * Set the given stream params.
> > - * Called by both virtio_snd_handle_pcm_set_params and during device
> > - * initialization.
> >  * Returns the response status code. (VIRTIO_SND_S_*).
> >  *
> >  * @s: VirtIOSound device
> > + * @stream_id: stream id
> >  * @params: The PCM params as defined in the virtio specification
> >  */
> > static
> > @@ -257,14 +275,25 @@ uint32_t virtio_snd_set_pcm_params(VirtIOSound *s,
> >                                    uint32_t stream_id,
> >                                    virtio_snd_pcm_set_params *params)
> > {
> > +    VirtIOSoundPCMStream *stream;
> >     virtio_snd_pcm_set_params *st_params;
> > 
> > -    if (stream_id >= s->snd_conf.streams || s->pcm.pcm_params == NULL) {
> > +    if (stream_id >= s->snd_conf.streams) {
> >         virtio_error(VIRTIO_DEVICE(s), "Streams have not been initialized.\n");
> >         return cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
> >     }
> > 
> > -    st_params = virtio_snd_pcm_get_params(s, stream_id);
> > +    stream = virtio_snd_pcm_get_stream(s, stream_id);
> > +
> > +    switch (stream->state) {
> > +    case VSND_PCMSTREAM_STATE_UNINITIALIZED:
> > +    case VSND_PCMSTREAM_STATE_PARAMS_SET:
> > +    case VSND_PCMSTREAM_STATE_PREPARED:
> > +    case VSND_PCMSTREAM_STATE_RELEASED:
> > +        break;
> > +    default:
> > +        return cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
> > +    }
> > 
> >     if (params->channels < 1 || params->channels > AUDIO_MAX_CHANNELS) {
> >         error_report("Number of channels is not supported.");
> > @@ -281,6 +310,8 @@ uint32_t virtio_snd_set_pcm_params(VirtIOSound *s,
> >         return cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
> >     }
> > 
> > +    st_params = virtio_snd_pcm_get_params(s, stream_id);
> > +
> >     st_params->buffer_bytes = le32_to_cpu(params->buffer_bytes);
> >     st_params->period_bytes = le32_to_cpu(params->period_bytes);
> >     st_params->features = le32_to_cpu(params->features);
> > @@ -289,6 +320,13 @@ uint32_t virtio_snd_set_pcm_params(VirtIOSound *s,
> >     st_params->format = params->format;
> >     st_params->rate = params->rate;
> > 
> > +    if (stream->state & VSND_PCMSTREAM_STATE_F_PREPARED) {
> > +        /* implicit VIRTIO_SND_R_PCM_RELEASE */
> > +        virtio_snd_pcm_flush(stream);
> > +    }
> > +
> > +    stream->state = VSND_PCMSTREAM_STATE_PARAMS_SET;
> > +
> >     return cpu_to_le32(VIRTIO_SND_S_OK);
> > }
> > 
> > @@ -398,15 +436,12 @@ static void virtio_snd_get_qemu_audsettings(audsettings *as,
> >  */
> > static void virtio_snd_pcm_close(VirtIOSoundPCMStream *stream)
> > {
> > -    if (stream) {
> > -        virtio_snd_pcm_flush(stream);
> > -        if (stream->info.direction == VIRTIO_SND_D_OUTPUT) {
> > -            audio_be_close_out(stream->s->audio_be, stream->voice.out);
> > -            stream->voice.out = NULL;
> > -        } else if (stream->info.direction == VIRTIO_SND_D_INPUT) {
> > -            audio_be_close_in(stream->s->audio_be, stream->voice.in);
> > -            stream->voice.in = NULL;
> > -        }
> > +    if (stream->info.direction == VIRTIO_SND_D_OUTPUT) {
> > +        audio_be_close_out(stream->s->audio_be, stream->voice.out);
> > +        stream->voice.out = NULL;
> > +    } else if (stream->info.direction == VIRTIO_SND_D_INPUT) {
> > +        audio_be_close_in(stream->s->audio_be, stream->voice.in);
> > +        stream->voice.in = NULL;
> >     }
> > }
> > 
> > @@ -423,32 +458,23 @@ static uint32_t virtio_snd_pcm_prepare(VirtIOSound *s, uint32_t stream_id)
> >     virtio_snd_pcm_set_params *params;
> >     VirtIOSoundPCMStream *stream;
> > 
> > -    if (s->pcm.streams == NULL ||
> > -        s->pcm.pcm_params == NULL ||
> > -        stream_id >= s->snd_conf.streams) {
> > +    stream = virtio_snd_pcm_get_stream(s, stream_id);
> > +    if (!stream) {
> >         return cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
> >     }
> > 
> > -    params = virtio_snd_pcm_get_params(s, stream_id);
> > -    if (params == NULL) {
> > +    switch (stream->state) {
> > +    case VSND_PCMSTREAM_STATE_PARAMS_SET:
> > +    case VSND_PCMSTREAM_STATE_PREPARED:
> > +    case VSND_PCMSTREAM_STATE_RELEASED:
> > +        break;
> > +    default:
> >         return cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
> >     }
> > 
> > -    stream = virtio_snd_pcm_get_stream(s, stream_id);
> > -    if (stream == NULL) {
> > -        stream = &s->streams[stream_id];
> > -        stream->active = false;
> > -        stream->latency_bytes = 0;
> > -
> > -        /*
> > -         * stream_id >= s->snd_conf.streams was checked before so this is
> > -         * in-bounds
> > -         */
> > -        s->pcm.streams[stream_id] = stream;
> > -    }
> > +    params = virtio_snd_pcm_get_params(s, stream_id);
> > 
> >     virtio_snd_get_qemu_audsettings(&as, params);
> > -    stream->params = *params;
> > 
> >     stream->positions[0] = VIRTIO_SND_CHMAP_FL;
> >     stream->positions[1] = VIRTIO_SND_CHMAP_FR;
> > @@ -472,6 +498,8 @@ static uint32_t virtio_snd_pcm_prepare(VirtIOSound *s, uint32_t stream_id)
> >         audio_be_set_volume_in_lr(s->audio_be, stream->voice.in, 0, 255, 255);
> >     }
> > 
> > +    stream->state = VSND_PCMSTREAM_STATE_PREPARED;
> > +
> >     return cpu_to_le32(VIRTIO_SND_S_OK);
> > }
> > 
> > @@ -542,12 +570,28 @@ static uint32_t virtio_snd_pcm_start_stop(VirtIOSound *s,
> >     }
> > 
> >     if (start) {
> > +        switch (stream->state) {
> > +        case VSND_PCMSTREAM_STATE_PREPARED:
> > +        case VSND_PCMSTREAM_STATE_STOPPED:
> > +            break;
> > +        default:
> > +            return cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
> > +        }
> > +
> >         trace_virtio_snd_handle_pcm_start(stream_id);
> > +        stream->state = VSND_PCMSTREAM_STATE_STARTED;
> >     } else {
> > +        switch (stream->state) {
> > +        case VSND_PCMSTREAM_STATE_STARTED:
> > +            break;
> > +        default:
> > +            return cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
> > +        }
> > +
> >         trace_virtio_snd_handle_pcm_stop(stream_id);
> > +        stream->state = VSND_PCMSTREAM_STATE_STOPPED;
> >     }
> > 
> > -    stream->active = start;
> >     if (stream->info.direction == VIRTIO_SND_D_OUTPUT) {
> >         audio_be_set_active_out(s->audio_be, stream->voice.out, start);
> >     } else {
> > @@ -641,6 +685,15 @@ static void virtio_snd_handle_pcm_release(VirtIOSound *s,
> >         return;
> >     }
> > 
> > +    switch (stream->state) {
> > +    case VSND_PCMSTREAM_STATE_PREPARED:
> > +    case VSND_PCMSTREAM_STATE_STOPPED:
> > +        break;
> > +    default:
> > +        cmd->resp.code = cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
> > +        return;
> > +    }
> > +
> >     if (virtio_snd_pcm_get_io_msgs_count(stream)) {
> >         /*
> >          * virtio-v1.2-csd01, 5.14.6.6.5.1,
> > @@ -655,6 +708,8 @@ static void virtio_snd_handle_pcm_release(VirtIOSound *s,
> >         virtio_snd_pcm_flush(stream);
> >     }
> > 
> > +    stream->state = VSND_PCMSTREAM_STATE_RELEASED;
> > +
> >     cmd->resp.code = cpu_to_le32(VIRTIO_SND_S_OK);
> > }
> > 
> > @@ -876,12 +931,11 @@ static void virtio_snd_handle_tx_xfer(VirtIODevice *vdev, VirtQueue *vq)
> >         }
> >         stream_id = le32_to_cpu(hdr.stream_id);
> > 
> > -        if (stream_id >= vsnd->snd_conf.streams
> > -            || vsnd->pcm.streams[stream_id] == NULL) {
> > +        if (stream_id >= vsnd->snd_conf.streams) {
> >             goto tx_err;
> >         }
> > 
> > -        stream = vsnd->pcm.streams[stream_id];
> > +        stream = &vsnd->streams[stream_id];
> >         if (stream->info.direction != VIRTIO_SND_D_OUTPUT) {
> >             goto tx_err;
> >         }
> > @@ -956,13 +1010,12 @@ static void virtio_snd_handle_rx_xfer(VirtIODevice *vdev, VirtQueue *vq)
> >         }
> >         stream_id = le32_to_cpu(hdr.stream_id);
> > 
> > -        if (stream_id >= vsnd->snd_conf.streams
> > -            || !vsnd->pcm.streams[stream_id]) {
> > +        if (stream_id >= vsnd->snd_conf.streams) {
> >             goto rx_err;
> >         }
> > 
> > -        stream = vsnd->pcm.streams[stream_id];
> > -        if (stream == NULL || stream->info.direction != VIRTIO_SND_D_INPUT) {
> > +        stream = &vsnd->streams[stream_id];
> > +        if (stream->info.direction != VIRTIO_SND_D_INPUT) {
> >             goto rx_err;
> >         }
> > 
> > @@ -1021,8 +1074,6 @@ static void virtio_snd_realize(DeviceState *dev, Error **errp)
> >     ERRP_GUARD();
> >     VirtIOSound *vsnd = VIRTIO_SND(dev);
> >     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> > -    virtio_snd_pcm_set_params default_params = { 0 };
> > -    uint32_t status;
> > 
> >     trace_virtio_snd_realize(vsnd);
> > 
> > @@ -1059,6 +1110,7 @@ static void virtio_snd_realize(DeviceState *dev, Error **errp)
> >     for (uint32_t i = 0; i < vsnd->snd_conf.streams; i++) {
> >         VirtIOSoundPCMStream *stream = &vsnd->streams[i];
> > 
> > +        stream->state = VSND_PCMSTREAM_STATE_UNINITIALIZED;
> >         stream->s = vsnd;
> >         QSIMPLEQ_INIT(&stream->queue);
> >         stream->info.hdr.hda_fn_nid = VIRTIO_SOUND_HDA_FN_NID;
> > @@ -1072,21 +1124,9 @@ static void virtio_snd_realize(DeviceState *dev, Error **errp)
> >         stream->info.channels_max = 2;
> >     }
> > 
> > -    vsnd->pcm.streams =
> > -        g_new0(VirtIOSoundPCMStream *, vsnd->snd_conf.streams);
> > -    vsnd->pcm.pcm_params =
> > -        g_new0(virtio_snd_pcm_set_params, vsnd->snd_conf.streams);
> > -
> >     virtio_init(vdev, VIRTIO_ID_SOUND, sizeof(virtio_snd_config));
> >     virtio_add_feature(&vsnd->features, VIRTIO_F_VERSION_1);
> > 
> > -    /* set default params for all streams */
> > -    default_params.features = 0;
> > -    default_params.buffer_bytes = cpu_to_le32(8192);
> > -    default_params.period_bytes = cpu_to_le32(2048);
> > -    default_params.channels = 2;
> > -    default_params.format = VIRTIO_SND_PCM_FMT_S16;
> > -    default_params.rate = VIRTIO_SND_PCM_RATE_48000;
> >     vsnd->queues[VIRTIO_SND_VQ_CONTROL] =
> >         virtio_add_queue(vdev, 64, virtio_snd_handle_ctrl);
> >     vsnd->queues[VIRTIO_SND_VQ_EVENT] =
> > @@ -1097,28 +1137,6 @@ static void virtio_snd_realize(DeviceState *dev, Error **errp)
> >         virtio_add_queue(vdev, 64, virtio_snd_handle_rx_xfer);
> >     QTAILQ_INIT(&vsnd->cmdq);
> >     QSIMPLEQ_INIT(&vsnd->invalid);
> > -
> > -    for (uint32_t i = 0; i < vsnd->snd_conf.streams; i++) {
> > -        status = virtio_snd_set_pcm_params(vsnd, i, &default_params);
> > -        if (status != cpu_to_le32(VIRTIO_SND_S_OK)) {
> > -            error_setg(errp,
> > -                       "Can't initialize stream params, device responded with %s.",
> > -                       print_code(status));
> > -            goto error_cleanup;
> > -        }
> > -        status = virtio_snd_pcm_prepare(vsnd, i);
> > -        if (status != cpu_to_le32(VIRTIO_SND_S_OK)) {
> > -            error_setg(errp,
> > -                       "Can't prepare streams, device responded with %s.",
> > -                       print_code(status));
> > -            goto error_cleanup;
> > -        }
> > -    }
> > -
> > -    return;
> > -
> > -error_cleanup:
> > -    virtio_snd_unrealize(dev);
> > }
> > 
> > static inline void update_latency(VirtIOSoundPCMStream *s, size_t used)
> > @@ -1167,7 +1185,7 @@ static void virtio_snd_pcm_out_cb(void *data, int available)
> >         if (!virtio_queue_ready(buffer->vq)) {
> >             return;
> >         }
> > -        if (!stream->active) {
> > +        if (!(stream->state & VSND_PCMSTREAM_STATE_F_ACTIVE)) {
> >             /* Stream has stopped, so do not perform audio_be_write. */
> >             return_tx_buffer(stream, buffer);
> >             continue;
> > @@ -1261,7 +1279,7 @@ static void virtio_snd_pcm_in_cb(void *data, int available)
> >         if (!virtio_queue_ready(buffer->vq)) {
> >             return;
> >         }
> > -        if (!stream->active) {
> > +        if (!(stream->state & VSND_PCMSTREAM_STATE_F_ACTIVE)) {
> >             /* Stream has stopped, so do not perform audio_be_read. */
> >             return_rx_buffer(stream, buffer);
> >             continue;
> > @@ -1334,17 +1352,16 @@ static void virtio_snd_unrealize(DeviceState *dev)
> >     qemu_del_vm_change_state_handler(vsnd->vmstate);
> >     trace_virtio_snd_unrealize(vsnd);
> > 
> > -    if (vsnd->pcm.streams) {
> > +    if (vsnd->streams) {
> > +        virtio_snd_process_cmdq(vsnd);
> >         for (uint32_t i = 0; i < vsnd->snd_conf.streams; i++) {
> > -            stream = vsnd->pcm.streams[i];
> > -            if (stream) {
> > -                virtio_snd_process_cmdq(stream->s);
> > -                virtio_snd_pcm_close(stream);
> > +            stream = &vsnd->streams[i];
> > +            if (stream->state & VSND_PCMSTREAM_STATE_F_PREPARED) {
> > +                virtio_snd_pcm_flush(stream);
> >             }
> > +            virtio_snd_pcm_close(stream);
> >         }
> > -        g_free(vsnd->pcm.streams);
> >     }
> > -    g_free(vsnd->pcm.pcm_params);
> >     g_free(vsnd->streams);
> >     vsnd->streams = NULL;
> >     virtio_delete_queue(vsnd->queues[VIRTIO_SND_VQ_CONTROL]);
> > @@ -1378,6 +1395,9 @@ static void virtio_snd_reset(VirtIODevice *vdev)
> >         VirtIOSoundPCMStream *stream = &vsnd->streams[i];
> >         VirtIOSoundPCMBuffer *buffer;
> > 
> > +        virtio_snd_pcm_close(stream);
> > +        stream->state = VSND_PCMSTREAM_STATE_UNINITIALIZED;
> > +
> >         while ((buffer = QSIMPLEQ_FIRST(&stream->queue))) {
> >             QSIMPLEQ_REMOVE_HEAD(&stream->queue, entry);
> >             virtio_snd_pcm_buffer_free(buffer);
> > diff --git a/include/hw/audio/virtio-snd.h b/include/hw/audio/virtio-snd.h
> > index 41c63b3f23b..72ef34e0976 100644
> > --- a/include/hw/audio/virtio-snd.h
> > +++ b/include/hw/audio/virtio-snd.h
> > @@ -75,8 +75,6 @@ typedef struct VirtIOSoundPCMStream VirtIOSoundPCMStream;
> > 
> > typedef struct virtio_snd_ctrl_command virtio_snd_ctrl_command;
> > 
> > -typedef struct VirtIOSoundPCM VirtIOSoundPCM;
> > -
> > typedef struct VirtIOSoundPCMBuffer VirtIOSoundPCMBuffer;
> > 
> > /*
> > @@ -121,31 +119,18 @@ struct VirtIOSoundPCMBuffer {
> >     uint8_t data[];
> > };
> > 
> > -struct VirtIOSoundPCM {
> > -    /*
> > -     * PCM parameters are a separate field instead of a VirtIOSoundPCMStream
> > -     * field, because the operation of PCM control requests is first
> > -     * VIRTIO_SND_R_PCM_SET_PARAMS and then VIRTIO_SND_R_PCM_PREPARE; this
> > -     * means that some times we get parameters without having an allocated
> > -     * stream yet.
> > -     */
> > -    virtio_snd_pcm_set_params *pcm_params;
> > -    VirtIOSoundPCMStream **streams;
> > -};
> > -
> > struct VirtIOSoundPCMStream {
> >     virtio_snd_pcm_info info;
> >     virtio_snd_pcm_set_params params;
> > +    uint32_t state;
> >     /* channel position values (VIRTIO_SND_CHMAP_XXX) */
> >     uint8_t positions[VIRTIO_SND_CHMAP_MAX_SIZE];
> >     VirtIOSound *s;
> > -    bool flushing;
> 
> Spurious change: this should be a separate patch.
> 
> >     audsettings as;
> >     union {
> >         SWVoiceIn *in;
> >         SWVoiceOut *out;
> >     } voice;
> > -    bool active;
> >     uint32_t latency_bytes;
> >     QSIMPLEQ_HEAD(, VirtIOSoundPCMBuffer) queue;
> > };
> > @@ -212,7 +197,6 @@ struct VirtIOSound {
> > 
> >     VirtQueue *queues[VIRTIO_SND_VQ_MAX];
> >     uint64_t features;
> > -    VirtIOSoundPCM pcm;
> >     VirtIOSoundPCMStream *streams;
> >     AudioBackend *audio_be;
> >     VMChangeStateEntry *vmstate;
> > -- 
> > 2.47.3
> >