@@ -47,3 +47,7 @@ virtio_snd_vm_state_running(void) "vm state running"
virtio_snd_vm_state_stopped(void) "vm state stopped"
virtio_snd_realize(void *snd) "snd %p: realize"
virtio_snd_unrealize(void *snd) "snd %p: unrealize"
+virtio_snd_handle_ctrl(void *vdev, void *vq) "snd %p: handle ctrl event for queue %p"
+virtio_snd_handle_code(uint32_t val, const char *code) "ctrl code msg val = %"PRIu32" == %s"
+virtio_snd_handle_chmap_info(void) "VIRTIO_SND_CHMAP_INFO called"
+virtio_snd_handle_event(void) "event queue callback called"
@@ -32,6 +32,29 @@
#define VIRTIO_SOUND_CHMAP_DEFAULT 0
#define VIRTIO_SOUND_HDA_FN_NID 0
+static uint32_t supported_formats = BIT(VIRTIO_SND_PCM_FMT_S8)
+ | BIT(VIRTIO_SND_PCM_FMT_U8)
+ | BIT(VIRTIO_SND_PCM_FMT_S16)
+ | BIT(VIRTIO_SND_PCM_FMT_U16)
+ | BIT(VIRTIO_SND_PCM_FMT_S32)
+ | BIT(VIRTIO_SND_PCM_FMT_U32)
+ | BIT(VIRTIO_SND_PCM_FMT_FLOAT);
+
+static uint32_t supported_rates = BIT(VIRTIO_SND_PCM_RATE_5512)
+ | BIT(VIRTIO_SND_PCM_RATE_8000)
+ | BIT(VIRTIO_SND_PCM_RATE_11025)
+ | BIT(VIRTIO_SND_PCM_RATE_16000)
+ | BIT(VIRTIO_SND_PCM_RATE_22050)
+ | BIT(VIRTIO_SND_PCM_RATE_32000)
+ | BIT(VIRTIO_SND_PCM_RATE_44100)
+ | BIT(VIRTIO_SND_PCM_RATE_48000)
+ | BIT(VIRTIO_SND_PCM_RATE_64000)
+ | BIT(VIRTIO_SND_PCM_RATE_88200)
+ | BIT(VIRTIO_SND_PCM_RATE_96000)
+ | BIT(VIRTIO_SND_PCM_RATE_176400)
+ | BIT(VIRTIO_SND_PCM_RATE_192000)
+ | BIT(VIRTIO_SND_PCM_RATE_384000);
+
static const VMStateDescription vmstate_virtio_snd_device = {
.name = TYPE_VIRTIO_SND,
.version_id = VIRTIO_SOUND_VM_VERSION,
@@ -100,13 +123,397 @@ virtio_snd_set_config(VirtIODevice *vdev, const uint8_t *config)
}
+static void
+virtio_snd_ctrl_cmd_free(virtio_snd_ctrl_command *cmd)
+{
+ g_free(cmd->elem);
+ g_free(cmd);
+}
+
+/*
+ * Get a specific stream from the virtio sound card device.
+ * Returns NULL if @stream_id is invalid or not allocated.
+ *
+ * @s: VirtIOSound device
+ * @stream_id: stream id
+ */
+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];
+}
+
+/*
+ * Get params for a specific stream.
+ *
+ * @s: VirtIOSound device
+ * @stream_id: stream id
+ */
+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];
+}
+
+/*
+ * 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
+ * @params: The PCM params as defined in the virtio specification
+ */
+static
+uint32_t virtio_snd_set_pcm_params(VirtIOSound *s,
+ uint32_t stream_id,
+ virtio_snd_pcm_set_params *params)
+{
+ virtio_snd_pcm_set_params *st_params;
+
+ if (stream_id >= s->snd_conf.streams || s->pcm->pcm_params == NULL) {
+ /*
+ * TODO: do we need to set DEVICE_NEEDS_RESET?
+ */
+ 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);
+
+ if (params->channels < 1 || params->channels > AUDIO_MAX_CHANNELS) {
+ error_report("Number of channels is not supported.");
+ return cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
+ }
+ if (!(supported_formats & BIT(params->format))) {
+ error_report("Stream format is not supported.");
+ return cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
+ }
+ if (!(supported_rates & BIT(params->rate))) {
+ error_report("Stream rate is not supported.");
+ return cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
+ }
+
+ 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);
+ /* the following are uint8_t, so there's no need to bswap the values. */
+ st_params->channels = params->channels;
+ st_params->format = params->format;
+ st_params->rate = params->rate;
+
+ return cpu_to_le32(VIRTIO_SND_S_OK);
+}
+
+/*
+ * Get a QEMU Audiosystem compatible format value from a VIRTIO_SND_PCM_FMT_*
+ */
+static AudioFormat virtio_snd_get_qemu_format(uint32_t format)
+{
+ #define CASE(FMT) \
+ case VIRTIO_SND_PCM_FMT_##FMT: \
+ return AUDIO_FORMAT_##FMT;
+
+ switch (format) {
+ CASE(U8)
+ CASE(S8)
+ CASE(U16)
+ CASE(S16)
+ CASE(U32)
+ CASE(S32)
+ case VIRTIO_SND_PCM_FMT_FLOAT:
+ return AUDIO_FORMAT_F32;
+ default:
+ g_assert_not_reached();
+ }
+
+ #undef CASE
+}
+
+/*
+ * Get a QEMU Audiosystem compatible frequency value from a
+ * VIRTIO_SND_PCM_RATE_*
+ */
+static uint32_t virtio_snd_get_qemu_freq(uint32_t rate)
+{
+ #define CASE(RATE) \
+ case VIRTIO_SND_PCM_RATE_##RATE: \
+ return RATE;
+
+ switch (rate) {
+ CASE(5512)
+ CASE(8000)
+ CASE(11025)
+ CASE(16000)
+ CASE(22050)
+ CASE(32000)
+ CASE(44100)
+ CASE(48000)
+ CASE(64000)
+ CASE(88200)
+ CASE(96000)
+ CASE(176400)
+ CASE(192000)
+ CASE(384000)
+ default:
+ g_assert_not_reached();
+ }
+
+ #undef CASE
+}
+
+/*
+ * Get QEMU Audiosystem compatible audsettings from virtio based pcm stream
+ * params.
+ */
+static void virtio_snd_get_qemu_audsettings(audsettings *as,
+ virtio_snd_pcm_set_params *params)
+{
+ 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;
+}
+
+/*
+ * Close a stream and free all its resources.
+ *
+ * @stream: VirtIOSoundPCMStream *stream
+ */
+static void virtio_snd_pcm_close(VirtIOSoundPCMStream *stream)
+{
+}
+
/*
- * Queue handler stub.
+ * Prepares a VirtIOSound card stream.
+ * Returns the response status code. (VIRTIO_SND_S_*).
+ *
+ * @s: VirtIOSound device
+ * @stream_id: stream id
+ */
+static uint32_t virtio_snd_pcm_prepare(VirtIOSound *s, uint32_t stream_id)
+{
+ audsettings as;
+ virtio_snd_pcm_set_params *params;
+ VirtIOSoundPCMStream *stream;
+
+ if (s->pcm->streams == NULL ||
+ s->pcm->pcm_params == NULL ||
+ stream_id >= s->snd_conf.streams) {
+ return cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
+ }
+
+ params = virtio_snd_pcm_get_params(s, stream_id);
+ if (params == NULL) {
+ return cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
+ }
+
+ stream = virtio_snd_pcm_get_stream(s, stream_id);
+ if (stream == NULL) {
+ stream = g_new0(VirtIOSoundPCMStream, 1);
+ stream->active = false;
+ stream->id = stream_id;
+ stream->pcm = s->pcm;
+ stream->s = s;
+
+ /*
+ * stream_id >= s->snd_conf.streams was checked before so this is
+ * in-bounds
+ */
+ s->pcm->streams[stream_id] = stream;
+ }
+
+ 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;
+ stream->positions[1] = VIRTIO_SND_CHMAP_FR;
+ stream->as = as;
+
+ return cpu_to_le32(VIRTIO_SND_S_OK);
+}
+
+static const char *print_code(uint32_t code)
+{
+ #define CASE(CODE) \
+ case VIRTIO_SND_R_##CODE: \
+ return "VIRTIO_SND_R_"#CODE
+
+ switch (code) {
+ CASE(JACK_INFO);
+ CASE(JACK_REMAP);
+ CASE(PCM_INFO);
+ CASE(PCM_SET_PARAMS);
+ CASE(PCM_PREPARE);
+ CASE(PCM_RELEASE);
+ CASE(PCM_START);
+ CASE(PCM_STOP);
+ CASE(CHMAP_INFO);
+ default:
+ return "invalid code";
+ }
+
+ #undef CASE
+};
+
+/*
+ * The actual processing done in virtio_snd_process_cmdq().
+ *
+ * @s: VirtIOSound device
+ * @cmd: control command request
+ */
+static inline void
+process_cmd(VirtIOSound *s, virtio_snd_ctrl_command *cmd)
+{
+ uint32_t code;
+ size_t msg_sz = iov_to_buf(cmd->elem->out_sg,
+ cmd->elem->out_num,
+ 0,
+ &cmd->ctrl,
+ sizeof(virtio_snd_hdr));
+
+ if (msg_sz != sizeof(virtio_snd_hdr)) {
+ /*
+ * TODO: do we need to set DEVICE_NEEDS_RESET?
+ */
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "%s: virtio-snd command size incorrect %zu vs \
+ %zu\n", __func__, msg_sz, sizeof(virtio_snd_hdr));
+ return;
+ }
+
+ code = le32_to_cpu(cmd->ctrl.code);
+
+ trace_virtio_snd_handle_code(code, print_code(code));
+
+ switch (code) {
+ case VIRTIO_SND_R_JACK_INFO:
+ case VIRTIO_SND_R_JACK_REMAP:
+ qemu_log_mask(LOG_UNIMP,
+ "virtio_snd: jack functionality is unimplemented.\n");
+ cmd->resp.code = cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
+ break;
+ case VIRTIO_SND_R_PCM_INFO:
+ case VIRTIO_SND_R_PCM_SET_PARAMS:
+ case VIRTIO_SND_R_PCM_PREPARE:
+ case VIRTIO_SND_R_PCM_START:
+ case VIRTIO_SND_R_PCM_STOP:
+ case VIRTIO_SND_R_PCM_RELEASE:
+ cmd->resp.code = cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
+ break;
+ case VIRTIO_SND_R_CHMAP_INFO:
+ qemu_log_mask(LOG_UNIMP,
+ "virtio_snd: chmap info functionality is unimplemented.\n");
+ trace_virtio_snd_handle_chmap_info();
+ cmd->resp.code = cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
+ break;
+ default:
+ /* error */
+ error_report("virtio snd header not recognized: %"PRIu32, code);
+ cmd->resp.code = cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
+ }
+
+ iov_from_buf(cmd->elem->in_sg,
+ cmd->elem->in_num,
+ 0,
+ &cmd->resp,
+ sizeof(virtio_snd_hdr));
+ virtqueue_push(cmd->vq, cmd->elem, sizeof(virtio_snd_hdr));
+ virtio_notify(VIRTIO_DEVICE(s), cmd->vq);
+}
+
+/*
+ * Consume all elements in command queue.
+ *
+ * @s: VirtIOSound device
+ */
+static void virtio_snd_process_cmdq(VirtIOSound *s)
+{
+ virtio_snd_ctrl_command *cmd;
+
+ if (unlikely(qatomic_read(&s->processing_cmdq))) {
+ return;
+ }
+
+ WITH_QEMU_LOCK_GUARD(&s->cmdq_mutex) {
+ qatomic_set(&s->processing_cmdq, true);
+ while (!QTAILQ_EMPTY(&s->cmdq)) {
+ cmd = QTAILQ_FIRST(&s->cmdq);
+
+ /* process command */
+ process_cmd(s, cmd);
+
+ QTAILQ_REMOVE(&s->cmdq, cmd, next);
+
+ virtio_snd_ctrl_cmd_free(cmd);
+ }
+ qatomic_set(&s->processing_cmdq, false);
+ }
+}
+
+/*
+ * The control message handler. Pops an element from the control virtqueue,
+ * and stores them to VirtIOSound's cmdq queue and finally calls
+ * virtio_snd_process_cmdq() for processing.
+ *
+ * @vdev: VirtIOSound device
+ * @vq: Control virtqueue
+ */
+static void virtio_snd_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
+{
+ VirtIOSound *s = VIRTIO_SND(vdev);
+ VirtQueueElement *elem;
+ virtio_snd_ctrl_command *cmd;
+
+ trace_virtio_snd_handle_ctrl(vdev, vq);
+
+ if (!virtio_queue_ready(vq)) {
+ return;
+ }
+
+ elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
+ while (elem) {
+ cmd = g_new0(virtio_snd_ctrl_command, 1);
+ cmd->elem = elem;
+ cmd->vq = vq;
+ cmd->resp.code = cpu_to_le32(VIRTIO_SND_S_OK);
+ QTAILQ_INSERT_TAIL(&s->cmdq, cmd, next);
+ elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
+ }
+
+ virtio_snd_process_cmdq(s);
+}
+
+/*
+ * The event virtqueue handler.
+ * Not implemented yet.
+ *
+ * @vdev: VirtIOSound device
+ * @vq: event vq
+ */
+static void virtio_snd_handle_event(VirtIODevice *vdev, VirtQueue *vq)
+{
+ qemu_log_mask(LOG_UNIMP, "virtio_snd: event queue is unimplemented.\n");
+ trace_virtio_snd_handle_event();
+}
+
+/*
+ * Stub buffer virtqueue handler.
*
* @vdev: VirtIOSound device
* @vq: virtqueue
*/
-static void virtio_snd_handle_queue(VirtIODevice *vdev, VirtQueue *vq) {}
+static void virtio_snd_handle_xfer(VirtIODevice *vdev, VirtQueue *vq) {}
static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
Error **errp)
@@ -140,12 +547,22 @@ 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;
+ vsnd->pcm = NULL;
vsnd->vmstate =
qemu_add_vm_change_state_handler(virtio_snd_vm_state_change, vsnd);
trace_virtio_snd_realize(vsnd);
+ vsnd->pcm = g_new0(VirtIOSoundPCM, 1);
+ vsnd->pcm->snd = vsnd;
+ 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);
@@ -172,25 +589,69 @@ static void virtio_snd_realize(DeviceState *dev, Error **errp)
AUD_register_card("virtio-sound", &vsnd->card, errp);
+ /* 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_queue);
+ virtio_add_queue(vdev, 64, virtio_snd_handle_ctrl);
vsnd->queues[VIRTIO_SND_VQ_EVENT] =
- virtio_add_queue(vdev, 64, virtio_snd_handle_queue);
+ virtio_add_queue(vdev, 64, virtio_snd_handle_event);
vsnd->queues[VIRTIO_SND_VQ_TX] =
- virtio_add_queue(vdev, 64, virtio_snd_handle_queue);
+ virtio_add_queue(vdev, 64, virtio_snd_handle_xfer);
vsnd->queues[VIRTIO_SND_VQ_RX] =
- virtio_add_queue(vdev, 64, virtio_snd_handle_queue);
+ virtio_add_queue(vdev, 64, virtio_snd_handle_xfer);
+ qemu_mutex_init(&vsnd->cmdq_mutex);
+ QTAILQ_INIT(&vsnd->cmdq);
+
+ 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 initalize stream params, device responded with %s.",
+ print_code(status));
+ return;
+ }
+ 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));
+ return;
+ }
+ }
}
static void virtio_snd_unrealize(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtIOSound *vsnd = VIRTIO_SND(dev);
+ VirtIOSoundPCMStream *stream;
qemu_del_vm_change_state_handler(vsnd->vmstate);
trace_virtio_snd_unrealize(vsnd);
+ if (vsnd->pcm) {
+ 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);
+ }
+ g_free(vsnd->pcm->pcm_params);
+ g_free(vsnd->pcm);
+ vsnd->pcm = NULL;
+ }
AUD_remove_card(&vsnd->card);
+ qemu_mutex_destroy(&vsnd->cmdq_mutex);
virtio_delete_queue(vsnd->queues[VIRTIO_SND_VQ_CONTROL]);
virtio_delete_queue(vsnd->queues[VIRTIO_SND_VQ_EVENT]);
virtio_delete_queue(vsnd->queues[VIRTIO_SND_VQ_TX]);
@@ -199,7 +660,19 @@ static void virtio_snd_unrealize(DeviceState *dev)
}
-static void virtio_snd_reset(VirtIODevice *vdev) {}
+static void virtio_snd_reset(VirtIODevice *vdev)
+{
+ VirtIOSound *s = VIRTIO_SND(vdev);
+ virtio_snd_ctrl_command *cmd;
+
+ WITH_QEMU_LOCK_GUARD(&s->cmdq_mutex) {
+ while (!QTAILQ_EMPTY(&s->cmdq)) {
+ cmd = QTAILQ_FIRST(&s->cmdq);
+ QTAILQ_REMOVE(&s->cmdq, cmd, next);
+ virtio_snd_ctrl_cmd_free(cmd);
+ }
+ }
+}
static void virtio_snd_class_init(ObjectClass *klass, void *data)
{
@@ -67,13 +67,122 @@ typedef struct virtio_snd_pcm_xfer virtio_snd_pcm_xfer;
/* I/O request status */
typedef struct virtio_snd_pcm_status virtio_snd_pcm_status;
-typedef struct VirtIOSound {
+/* device structs */
+
+typedef struct VirtIOSound VirtIOSound;
+
+typedef struct VirtIOSoundPCMStream VirtIOSoundPCMStream;
+
+typedef struct virtio_snd_ctrl_command virtio_snd_ctrl_command;
+
+typedef struct VirtIOSoundPCM VirtIOSoundPCM;
+
+struct VirtIOSoundPCM {
+ VirtIOSound *snd;
+ /*
+ * 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 {
+ VirtIOSoundPCM *pcm;
+ virtio_snd_pcm_info info;
+ virtio_snd_pcm_set_params params;
+ uint32_t id;
+ /* channel position values (VIRTIO_SND_CHMAP_XXX) */
+ uint8_t positions[VIRTIO_SND_CHMAP_MAX_SIZE];
+ VirtIOSound *s;
+ bool flushing;
+ audsettings as;
+ union {
+ SWVoiceIn *in;
+ SWVoiceOut *out;
+ } voice;
+ bool active;
+};
+
+/*
+ * PCM stream state machine.
+ * -------------------------
+ *
+ * 5.14.6.6.1 PCM Command Lifecycle
+ * ================================
+ *
+ * A PCM stream has the following command lifecycle:
+ * - `SET PARAMETERS`
+ * The driver negotiates the stream parameters (format, transport, etc) with
+ * the device.
+ * Possible valid transitions: `SET PARAMETERS`, `PREPARE`.
+ * - `PREPARE`
+ * The device prepares the stream (allocates resources, etc).
+ * Possible valid transitions: `SET PARAMETERS`, `PREPARE`, `START`,
+ * `RELEASE`. Output only: the driver transfers data for pre-buffing.
+ * - `START`
+ * The device starts the stream (unmute, putting into running state, etc).
+ * Possible valid transitions: `STOP`.
+ * The driver transfers data to/from the stream.
+ * - `STOP`
+ * The device stops the stream (mute, putting into non-running state, etc).
+ * Possible valid transitions: `START`, `RELEASE`.
+ * - `RELEASE`
+ * The device releases the stream (frees resources, etc).
+ * Possible valid transitions: `SET PARAMETERS`, `PREPARE`.
+ *
+ * +---------------+ +---------+ +---------+ +-------+ +-------+
+ * | SetParameters | | Prepare | | Release | | Start | | Stop |
+ * +---------------+ +---------+ +---------+ +-------+ +-------+
+ * |- | | | |
+ * || | | | |
+ * |< | | | |
+ * |------------->| | | |
+ * |<-------------| | | |
+ * | |- | | |
+ * | || | | |
+ * | |< | | |
+ * | |--------------------->| |
+ * | |---------->| | |
+ * | | | |-------->|
+ * | | | |<--------|
+ * | | |<-------------------|
+ * |<-------------------------| | |
+ * | |<----------| | |
+ *
+ * CTRL in the VirtIOSound device
+ * ==============================
+ *
+ * The control messages that affect the state of a stream arrive in the
+ * `virtio_snd_handle_ctrl()` queue callback and are of type `struct
+ * virtio_snd_ctrl_command`. They are stored in a queue field in the device
+ * type, `VirtIOSound`. This allows deferring the CTRL request completion if
+ * it's not immediately possible due to locking/state reasons.
+ *
+ * The CTRL message is finally handled in `process_cmd()`.
+ */
+struct VirtIOSound {
VirtIODevice parent_obj;
VirtQueue *queues[VIRTIO_SND_VQ_MAX];
uint64_t features;
+ VirtIOSoundPCM *pcm;
QEMUSoundCard card;
VMChangeStateEntry *vmstate;
virtio_snd_config snd_conf;
-} VirtIOSound;
+ QemuMutex cmdq_mutex;
+ QTAILQ_HEAD(, virtio_snd_ctrl_command) cmdq;
+ bool processing_cmdq;
+};
+
+struct virtio_snd_ctrl_command {
+ VirtQueueElement *elem;
+ VirtQueue *vq;
+ virtio_snd_hdr ctrl;
+ virtio_snd_hdr resp;
+ QTAILQ_ENTRY(virtio_snd_ctrl_command) next;
+};
#endif