It is much easier to migrate an array of structs than individual
structs that are accessed via a pointer to a pointer to an array
of pointers to struct.

For this reason, allocate an array of streams in
virtio_snd_realize() and initialise all stream variables that
are constant at runtime immediately after allocation.

This makes it easier to remove the virtio_snd_set_pcm_params()
and virtio_snd_pcm_prepare() calls in the realisation phase and
to migrate the audio streams of the virtio sound device after
the next few patches.

Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
---
 hw/audio/virtio-snd.c         | 37 ++++++++++++++++++++++-------------
 include/hw/audio/virtio-snd.h |  1 +
 2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/hw/audio/virtio-snd.c b/hw/audio/virtio-snd.c
index 7ed5f3de3e..e5497b6bf6 100644
--- a/hw/audio/virtio-snd.c
+++ b/hw/audio/virtio-snd.c
@@ -448,12 +448,9 @@ static uint32_t virtio_snd_pcm_prepare(VirtIOSound *s, uint32_t stream_id)
 
     stream = virtio_snd_pcm_get_stream(s, stream_id);
     if (stream == NULL) {
-        stream = g_new0(VirtIOSoundPCMStream, 1);
+        stream = &s->streams[stream_id];
         stream->active = false;
-        stream->id = stream_id;
         stream->pcm = s->pcm;
-        stream->s = s;
-        QSIMPLEQ_INIT(&stream->queue);
 
         /*
          * stream_id >= s->snd_conf.streams was checked before so this is
@@ -463,14 +460,6 @@ static uint32_t virtio_snd_pcm_prepare(VirtIOSound *s, uint32_t stream_id)
     }
 
     virtio_snd_get_qemu_audsettings(&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;
-    stream->info.features = 0;
-    stream->info.channels_min = 1;
-    stream->info.channels_max = as.nchannels;
-    stream->info.formats = supported_formats;
-    stream->info.rates = supported_rates;
     stream->params = *params;
 
     stream->positions[0] = VIRTIO_SND_CHMAP_FL;
@@ -1040,6 +1029,25 @@ static void virtio_snd_realize(DeviceState *dev, Error **errp)
     vsnd->vmstate =
         qemu_add_vm_change_state_handler(virtio_snd_vm_state_change, vsnd);
 
+    vsnd->streams = g_new0(VirtIOSoundPCMStream, vsnd->snd_conf.streams);
+
+    for (uint32_t i = 0; i < vsnd->snd_conf.streams; i++) {
+        VirtIOSoundPCMStream *stream = &vsnd->streams[i];
+
+        stream->id = i;
+        stream->s = vsnd;
+        QSIMPLEQ_INIT(&stream->queue);
+        stream->info.hdr.hda_fn_nid = VIRTIO_SOUND_HDA_FN_NID;
+        stream->info.features = 0;
+        stream->info.formats = supported_formats;
+        stream->info.rates = supported_rates;
+        stream->info.direction =
+            i < vsnd->snd_conf.streams / 2 + (vsnd->snd_conf.streams & 1)
+            ? VIRTIO_SND_D_OUTPUT : VIRTIO_SND_D_INPUT;
+        stream->info.channels_min = 1;
+        stream->info.channels_max = 2;
+    }
+
     vsnd->pcm = g_new0(VirtIOSoundPCM, 1);
     vsnd->pcm->snd = vsnd;
     vsnd->pcm->streams =
@@ -1280,14 +1288,13 @@ static void virtio_snd_unrealize(DeviceState *dev)
     qemu_del_vm_change_state_handler(vsnd->vmstate);
     trace_virtio_snd_unrealize(vsnd);
 
-    if (vsnd->pcm) {
+    if (vsnd->streams) {
         if (vsnd->pcm->streams) {
             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);
-                    g_free(stream);
                 }
             }
             g_free(vsnd->pcm->streams);
@@ -1295,6 +1302,8 @@ static void virtio_snd_unrealize(DeviceState *dev)
         g_free(vsnd->pcm->pcm_params);
         g_free(vsnd->pcm);
         vsnd->pcm = NULL;
+        g_free(vsnd->streams);
+        vsnd->streams = NULL;
     }
     AUD_remove_card(&vsnd->card);
     virtio_delete_queue(vsnd->queues[VIRTIO_SND_VQ_CONTROL]);
diff --git a/include/hw/audio/virtio-snd.h b/include/hw/audio/virtio-snd.h
index a2868067fb..95aef8192a 100644
--- a/include/hw/audio/virtio-snd.h
+++ b/include/hw/audio/virtio-snd.h
@@ -215,6 +215,7 @@ struct VirtIOSound {
     VirtQueue *queues[VIRTIO_SND_VQ_MAX];
     uint64_t features;
     VirtIOSoundPCM *pcm;
+    VirtIOSoundPCMStream *streams;
     QEMUSoundCard card;
     VMChangeStateEntry *vmstate;
     virtio_snd_config snd_conf;
-- 
2.35.3