audio/pwaudio.c: Add Pipewire audio backend for QEMU

This commit adds a new audiodev backend to allow QEMU to use Pipewire as
both an audio sink and source. This backend is available on most systems

Add Pipewire entry points for QEMU Pipewire audio backend
Add wrappers for QEMU Pipewire audio backend in qpw_pcm_ops()
qpw_write function returns the current state of the stream to pwaudio
and Writes some data to the server for playback streams using pipewire
spa_ringbuffer implementation.
qpw_read function returns the current state of the stream to pwaudio and
reads some data from the server for capture streams using pipewire
spa_ringbuffer implementation. These functions qpw_write and qpw_read
are called during playback and capture.
Added some functions that convert pw audio formats to QEMU audio format
and vice versa which would be needed in the pipewire audio sink and
source functions qpw_init_in() & qpw_init_out().
These methods that implement playback and recording will create streams
for playback and capture that will start processing and will result in
the on_process callbacks to be called.
Built a connection to the Pipewire sound system server in the
qpw_audio_init() method.

Signed-off-by: Dorinda Bassey <dbassey@redhat.com>
Reviewed-by: Volker Rümelin <vr_qemu@t-online.de>
Message-Id: <20230417105654.32328-1-dbassey@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

audio/audio.c

@@ -2061,6 +2061,9 @@ void audio_create_pdos(Audiodev *dev)
 #ifdef CONFIG_AUDIO_PA
         CASE(PA, pa, Pa);
 #endif
+#ifdef CONFIG_AUDIO_PIPEWIRE
+        CASE(PIPEWIRE, pipewire, Pipewire);
+#endif
 #ifdef CONFIG_AUDIO_SDL
         CASE(SDL, sdl, Sdl);
 #endif

audio/audio_template.h

@@ -362,6 +362,10 @@ AudiodevPerDirectionOptions *glue(audio_get_pdo_, TYPE)(Audiodev *dev)
     case AUDIODEV_DRIVER_PA:
         return qapi_AudiodevPaPerDirectionOptions_base(dev->u.pa.TYPE);
 #endif
+#ifdef CONFIG_AUDIO_PIPEWIRE
+    case AUDIODEV_DRIVER_PIPEWIRE:
+        return qapi_AudiodevPipewirePerDirectionOptions_base(dev->u.pipewire.TYPE);
+#endif
 #ifdef CONFIG_AUDIO_SDL
     case AUDIODEV_DRIVER_SDL:
         return qapi_AudiodevSdlPerDirectionOptions_base(dev->u.sdl.TYPE);

audio/meson.build

@@ -19,6 +19,7 @@ foreach m : [
   ['sdl', sdl, files('sdlaudio.c')],
   ['jack', jack, files('jackaudio.c')],
   ['sndio', sndio, files('sndioaudio.c')],
+  ['pipewire', pipewire, files('pwaudio.c')],
   ['spice', spice, files('spiceaudio.c')]
 ]
   if m[1].found()

audio/pwaudio.c

@@ -0,0 +1,915 @@
+/*
+ * QEMU Pipewire audio driver
+ *
+ * Copyright (c) 2023 Red Hat Inc.
+ *
+ * Author: Dorinda Bassey       <dbassey@redhat.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/module.h"
+#include "audio.h"
+#include <errno.h>
+#include "qemu/error-report.h"
+#include <spa/param/audio/format-utils.h>
+#include <spa/utils/ringbuffer.h>
+#include <spa/utils/result.h>
+#include <spa/param/props.h>
+
+#include <pipewire/pipewire.h>
+#include "trace.h"
+
+#define AUDIO_CAP "pipewire"
+#define RINGBUFFER_SIZE    (1u << 22)
+#define RINGBUFFER_MASK    (RINGBUFFER_SIZE - 1)
+
+#include "audio_int.h"
+
+typedef struct pwvolume {
+    uint32_t channels;
+    float values[SPA_AUDIO_MAX_CHANNELS];
+} pwvolume;
+
+typedef struct pwaudio {
+    Audiodev *dev;
+    struct pw_thread_loop *thread_loop;
+    struct pw_context *context;
+
+    struct pw_core *core;
+    struct spa_hook core_listener;
+    int last_seq, pending_seq, error;
+} pwaudio;
+
+typedef struct PWVoice {
+    pwaudio *g;
+    struct pw_stream *stream;
+    struct spa_hook stream_listener;
+    struct spa_audio_info_raw info;
+    uint32_t highwater_mark;
+    uint32_t frame_size, req;
+    struct spa_ringbuffer ring;
+    uint8_t buffer[RINGBUFFER_SIZE];
+
+    pwvolume volume;
+    bool muted;
+} PWVoice;
+
+typedef struct PWVoiceOut {
+    HWVoiceOut hw;
+    PWVoice v;
+} PWVoiceOut;
+
+typedef struct PWVoiceIn {
+    HWVoiceIn hw;
+    PWVoice v;
+} PWVoiceIn;
+
+static void
+stream_destroy(void *data)
+{
+    PWVoice *v = (PWVoice *) data;
+    spa_hook_remove(&v->stream_listener);
+    v->stream = NULL;
+}
+
+/* output data processing function to read stuffs from the buffer */
+static void
+playback_on_process(void *data)
+{
+    PWVoice *v = data;
+    void *p;
+    struct pw_buffer *b;
+    struct spa_buffer *buf;
+    uint32_t req, index, n_bytes;
+    int32_t avail;
+
+    assert(v->stream);
+
+    /* obtain a buffer to read from */
+    b = pw_stream_dequeue_buffer(v->stream);
+    if (b == NULL) {
+        error_report("out of buffers: %s", strerror(errno));
+        return;
+    }
+
+    buf = b->buffer;
+    p = buf->datas[0].data;
+    if (p == NULL) {
+        return;
+    }
+    /* calculate the total no of bytes to read data from buffer */
+    req = b->requested * v->frame_size;
+    if (req == 0) {
+        req = v->req;
+    }
+    n_bytes = SPA_MIN(req, buf->datas[0].maxsize);
+
+    /* get no of available bytes to read data from buffer */
+    avail = spa_ringbuffer_get_read_index(&v->ring, &index);
+
+    if (avail <= 0) {
+        PWVoiceOut *vo = container_of(data, PWVoiceOut, v);
+        audio_pcm_info_clear_buf(&vo->hw.info, p, n_bytes / v->frame_size);
+    } else {
+        if ((uint32_t) avail < n_bytes) {
+            /*
+             * PipeWire immediately calls this callback again if we provide
+             * less than n_bytes. Then audio_pcm_info_clear_buf() fills the
+             * rest of the buffer with silence.
+             */
+            n_bytes = avail;
+        }
+
+        spa_ringbuffer_read_data(&v->ring,
+                                    v->buffer, RINGBUFFER_SIZE,
+                                    index & RINGBUFFER_MASK, p, n_bytes);
+
+        index += n_bytes;
+        spa_ringbuffer_read_update(&v->ring, index);
+
+    }
+    buf->datas[0].chunk->offset = 0;
+    buf->datas[0].chunk->stride = v->frame_size;
+    buf->datas[0].chunk->size = n_bytes;
+
+    /* queue the buffer for playback */
+    pw_stream_queue_buffer(v->stream, b);
+}
+
+/* output data processing function to generate stuffs in the buffer */
+static void
+capture_on_process(void *data)
+{
+    PWVoice *v = (PWVoice *) data;
+    void *p;
+    struct pw_buffer *b;
+    struct spa_buffer *buf;
+    int32_t filled;
+    uint32_t index, offs, n_bytes;
+
+    assert(v->stream);
+
+    /* obtain a buffer */
+    b = pw_stream_dequeue_buffer(v->stream);
+    if (b == NULL) {
+        error_report("out of buffers: %s", strerror(errno));
+        return;
+    }
+
+    /* Write data into buffer */
+    buf = b->buffer;
+    p = buf->datas[0].data;
+    if (p == NULL) {
+        return;
+    }
+    offs = SPA_MIN(buf->datas[0].chunk->offset, buf->datas[0].maxsize);
+    n_bytes = SPA_MIN(buf->datas[0].chunk->size, buf->datas[0].maxsize - offs);
+
+    filled = spa_ringbuffer_get_write_index(&v->ring, &index);
+
+
+    if (filled < 0) {
+        error_report("%p: underrun write:%u filled:%d", p, index, filled);
+    } else {
+        if ((uint32_t) filled + n_bytes > RINGBUFFER_SIZE) {
+            error_report("%p: overrun write:%u filled:%d + size:%u > max:%u",
+            p, index, filled, n_bytes, RINGBUFFER_SIZE);
+        }
+    }
+    spa_ringbuffer_write_data(&v->ring,
+                                v->buffer, RINGBUFFER_SIZE,
+                                index & RINGBUFFER_MASK,
+                                SPA_PTROFF(p, offs, void), n_bytes);
+    index += n_bytes;
+    spa_ringbuffer_write_update(&v->ring, index);
+
+    /* queue the buffer for playback */
+    pw_stream_queue_buffer(v->stream, b);
+}
+
+static void
+on_stream_state_changed(void *data, enum pw_stream_state old,
+                        enum pw_stream_state state, const char *error)
+{
+    PWVoice *v = (PWVoice *) data;
+
+    trace_pw_state_changed(pw_stream_get_node_id(v->stream),
+                           pw_stream_state_as_string(state));
+
+    switch (state) {
+    case PW_STREAM_STATE_ERROR:
+    case PW_STREAM_STATE_UNCONNECTED:
+        break;
+    case PW_STREAM_STATE_PAUSED:
+    case PW_STREAM_STATE_CONNECTING:
+    case PW_STREAM_STATE_STREAMING:
+        break;
+    }
+}
+
+static const struct pw_stream_events capture_stream_events = {
+    PW_VERSION_STREAM_EVENTS,
+    .destroy = stream_destroy,
+    .state_changed = on_stream_state_changed,
+    .process = capture_on_process
+};
+
+static const struct pw_stream_events playback_stream_events = {
+    PW_VERSION_STREAM_EVENTS,
+    .destroy = stream_destroy,
+    .state_changed = on_stream_state_changed,
+    .process = playback_on_process
+};
+
+static size_t
+qpw_read(HWVoiceIn *hw, void *data, size_t len)
+{
+    PWVoiceIn *pw = (PWVoiceIn *) hw;
+    PWVoice *v = &pw->v;
+    pwaudio *c = v->g;
+    const char *error = NULL;
+    size_t l;
+    int32_t avail;
+    uint32_t index;
+
+    pw_thread_loop_lock(c->thread_loop);
+    if (pw_stream_get_state(v->stream, &error) != PW_STREAM_STATE_STREAMING) {
+        /* wait for stream to become ready */
+        l = 0;
+        goto done_unlock;
+    }
+    /* get no of available bytes to read data from buffer */
+    avail = spa_ringbuffer_get_read_index(&v->ring, &index);
+
+    trace_pw_read(avail, index, len);
+
+    if (avail < (int32_t) len) {
+        len = avail;
+    }
+
+    spa_ringbuffer_read_data(&v->ring,
+                             v->buffer, RINGBUFFER_SIZE,
+                             index & RINGBUFFER_MASK, data, len);
+    index += len;
+    spa_ringbuffer_read_update(&v->ring, index);
+    l = len;
+
+done_unlock:
+    pw_thread_loop_unlock(c->thread_loop);
+    return l;
+}
+
+static size_t qpw_buffer_get_free(HWVoiceOut *hw)
+{
+    PWVoiceOut *pw = (PWVoiceOut *)hw;
+    PWVoice *v = &pw->v;
+    pwaudio *c = v->g;
+    const char *error = NULL;
+    int32_t filled, avail;
+    uint32_t index;
+
+    pw_thread_loop_lock(c->thread_loop);
+    if (pw_stream_get_state(v->stream, &error) != PW_STREAM_STATE_STREAMING) {
+        /* wait for stream to become ready */
+        avail = 0;
+        goto done_unlock;
+    }
+
+    filled = spa_ringbuffer_get_write_index(&v->ring, &index);
+    avail = v->highwater_mark - filled;
+
+done_unlock:
+    pw_thread_loop_unlock(c->thread_loop);
+    return avail;
+}
+
+static size_t
+qpw_write(HWVoiceOut *hw, void *data, size_t len)
+{
+    PWVoiceOut *pw = (PWVoiceOut *) hw;
+    PWVoice *v = &pw->v;
+    pwaudio *c = v->g;
+    const char *error = NULL;
+    int32_t filled, avail;
+    uint32_t index;
+
+    pw_thread_loop_lock(c->thread_loop);
+    if (pw_stream_get_state(v->stream, &error) != PW_STREAM_STATE_STREAMING) {
+        /* wait for stream to become ready */
+        len = 0;
+        goto done_unlock;
+    }
+    filled = spa_ringbuffer_get_write_index(&v->ring, &index);
+    avail = v->highwater_mark - filled;
+
+    trace_pw_write(filled, avail, index, len);
+
+    if (len > avail) {
+        len = avail;
+    }
+
+    if (filled < 0) {
+        error_report("%p: underrun write:%u filled:%d", pw, index, filled);
+    } else {
+        if ((uint32_t) filled + len > RINGBUFFER_SIZE) {
+            error_report("%p: overrun write:%u filled:%d + size:%zu > max:%u",
+            pw, index, filled, len, RINGBUFFER_SIZE);
+        }
+    }
+
+    spa_ringbuffer_write_data(&v->ring,
+                                v->buffer, RINGBUFFER_SIZE,
+                                index & RINGBUFFER_MASK, data, len);
+    index += len;
+    spa_ringbuffer_write_update(&v->ring, index);
+
+done_unlock:
+    pw_thread_loop_unlock(c->thread_loop);
+    return len;
+}
+
+static int
+audfmt_to_pw(AudioFormat fmt, int endianness)
+{
+    int format;
+
+    switch (fmt) {
+    case AUDIO_FORMAT_S8:
+        format = SPA_AUDIO_FORMAT_S8;
+        break;
+    case AUDIO_FORMAT_U8:
+        format = SPA_AUDIO_FORMAT_U8;
+        break;
+    case AUDIO_FORMAT_S16:
+        format = endianness ? SPA_AUDIO_FORMAT_S16_BE : SPA_AUDIO_FORMAT_S16_LE;
+        break;
+    case AUDIO_FORMAT_U16:
+        format = endianness ? SPA_AUDIO_FORMAT_U16_BE : SPA_AUDIO_FORMAT_U16_LE;
+        break;
+    case AUDIO_FORMAT_S32:
+        format = endianness ? SPA_AUDIO_FORMAT_S32_BE : SPA_AUDIO_FORMAT_S32_LE;
+        break;
+    case AUDIO_FORMAT_U32:
+        format = endianness ? SPA_AUDIO_FORMAT_U32_BE : SPA_AUDIO_FORMAT_U32_LE;
+        break;
+    case AUDIO_FORMAT_F32:
+        format = endianness ? SPA_AUDIO_FORMAT_F32_BE : SPA_AUDIO_FORMAT_F32_LE;
+        break;
+    default:
+        dolog("Internal logic error: Bad audio format %d\n", fmt);
+        format = SPA_AUDIO_FORMAT_U8;
+        break;
+    }
+    return format;
+}
+
+static AudioFormat
+pw_to_audfmt(enum spa_audio_format fmt, int *endianness,
+             uint32_t *sample_size)
+{
+    switch (fmt) {
+    case SPA_AUDIO_FORMAT_S8:
+        *sample_size = 1;
+        return AUDIO_FORMAT_S8;
+    case SPA_AUDIO_FORMAT_U8:
+        *sample_size = 1;
+        return AUDIO_FORMAT_U8;
+    case SPA_AUDIO_FORMAT_S16_BE:
+        *sample_size = 2;
+        *endianness = 1;
+        return AUDIO_FORMAT_S16;
+    case SPA_AUDIO_FORMAT_S16_LE:
+        *sample_size = 2;
+        *endianness = 0;
+        return AUDIO_FORMAT_S16;
+    case SPA_AUDIO_FORMAT_U16_BE:
+        *sample_size = 2;
+        *endianness = 1;
+        return AUDIO_FORMAT_U16;
+    case SPA_AUDIO_FORMAT_U16_LE:
+        *sample_size = 2;
+        *endianness = 0;
+        return AUDIO_FORMAT_U16;
+    case SPA_AUDIO_FORMAT_S32_BE:
+        *sample_size = 4;
+        *endianness = 1;
+        return AUDIO_FORMAT_S32;
+    case SPA_AUDIO_FORMAT_S32_LE:
+        *sample_size = 4;
+        *endianness = 0;
+        return AUDIO_FORMAT_S32;
+    case SPA_AUDIO_FORMAT_U32_BE:
+        *sample_size = 4;
+        *endianness = 1;
+        return AUDIO_FORMAT_U32;
+    case SPA_AUDIO_FORMAT_U32_LE:
+        *sample_size = 4;
+        *endianness = 0;
+        return AUDIO_FORMAT_U32;
+    case SPA_AUDIO_FORMAT_F32_BE:
+        *sample_size = 4;
+        *endianness = 1;
+        return AUDIO_FORMAT_F32;
+    case SPA_AUDIO_FORMAT_F32_LE:
+        *sample_size = 4;
+        *endianness = 0;
+        return AUDIO_FORMAT_F32;
+    default:
+        *sample_size = 1;
+        dolog("Internal logic error: Bad spa_audio_format %d\n", fmt);
+        return AUDIO_FORMAT_U8;
+    }
+}
+
+static int
+create_stream(pwaudio *c, PWVoice *v, const char *stream_name,
+              const char *name, enum spa_direction dir)
+{
+    int res;
+    uint32_t n_params;
+    const struct spa_pod *params[2];
+    uint8_t buffer[1024];
+    struct spa_pod_builder b;
+    uint64_t buf_samples;
+    struct pw_properties *props;
+
+    props = pw_properties_new(NULL, NULL);
+
+    /* 75% of the timer period for faster updates */
+    buf_samples = (uint64_t)v->g->dev->timer_period * v->info.rate
+                    * 3 / 4 / 1000000;
+    pw_properties_setf(props, PW_KEY_NODE_LATENCY, "%" PRIu64 "/%u",
+                       buf_samples, v->info.rate);
+
+    trace_pw_period(buf_samples, v->info.rate);
+    if (name) {
+        pw_properties_set(props, PW_KEY_TARGET_OBJECT, name);
+    }
+    v->stream = pw_stream_new(c->core, stream_name, props);
+
+    if (v->stream == NULL) {
+        return -1;
+    }
+
+    if (dir == SPA_DIRECTION_INPUT) {
+        pw_stream_add_listener(v->stream,
+                            &v->stream_listener, &capture_stream_events, v);
+    } else {
+        pw_stream_add_listener(v->stream,
+                            &v->stream_listener, &playback_stream_events, v);
+    }
+
+    n_params = 0;
+    spa_pod_builder_init(&b, buffer, sizeof(buffer));
+    params[n_params++] = spa_format_audio_raw_build(&b,
+                            SPA_PARAM_EnumFormat,
+                            &v->info);
+
+    /* connect the stream to a sink or source */
+    res = pw_stream_connect(v->stream,
+                            dir ==
+                            SPA_DIRECTION_INPUT ? PW_DIRECTION_INPUT :
+                            PW_DIRECTION_OUTPUT, PW_ID_ANY,
+                            PW_STREAM_FLAG_AUTOCONNECT |
+                            PW_STREAM_FLAG_INACTIVE |
+                            PW_STREAM_FLAG_MAP_BUFFERS |
+                            PW_STREAM_FLAG_RT_PROCESS, params, n_params);
+    if (res < 0) {
+        pw_stream_destroy(v->stream);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int
+qpw_stream_new(pwaudio *c, PWVoice *v, const char *stream_name,
+               const char *name, enum spa_direction dir)
+{
+    int r;
+
+    switch (v->info.channels) {
+    case 8:
+        v->info.position[0] = SPA_AUDIO_CHANNEL_FL;
+        v->info.position[1] = SPA_AUDIO_CHANNEL_FR;
+        v->info.position[2] = SPA_AUDIO_CHANNEL_FC;
+        v->info.position[3] = SPA_AUDIO_CHANNEL_LFE;
+        v->info.position[4] = SPA_AUDIO_CHANNEL_RL;
+        v->info.position[5] = SPA_AUDIO_CHANNEL_RR;
+        v->info.position[6] = SPA_AUDIO_CHANNEL_SL;
+        v->info.position[7] = SPA_AUDIO_CHANNEL_SR;
+        break;
+    case 6:
+        v->info.position[0] = SPA_AUDIO_CHANNEL_FL;
+        v->info.position[1] = SPA_AUDIO_CHANNEL_FR;
+        v->info.position[2] = SPA_AUDIO_CHANNEL_FC;
+        v->info.position[3] = SPA_AUDIO_CHANNEL_LFE;
+        v->info.position[4] = SPA_AUDIO_CHANNEL_RL;
+        v->info.position[5] = SPA_AUDIO_CHANNEL_RR;
+        break;
+    case 5:
+        v->info.position[0] = SPA_AUDIO_CHANNEL_FL;
+        v->info.position[1] = SPA_AUDIO_CHANNEL_FR;
+        v->info.position[2] = SPA_AUDIO_CHANNEL_FC;
+        v->info.position[3] = SPA_AUDIO_CHANNEL_LFE;
+        v->info.position[4] = SPA_AUDIO_CHANNEL_RC;
+        break;
+    case 4:
+        v->info.position[0] = SPA_AUDIO_CHANNEL_FL;
+        v->info.position[1] = SPA_AUDIO_CHANNEL_FR;
+        v->info.position[2] = SPA_AUDIO_CHANNEL_FC;
+        v->info.position[3] = SPA_AUDIO_CHANNEL_RC;
+        break;
+    case 3:
+        v->info.position[0] = SPA_AUDIO_CHANNEL_FL;
+        v->info.position[1] = SPA_AUDIO_CHANNEL_FR;
+        v->info.position[2] = SPA_AUDIO_CHANNEL_LFE;
+        break;
+    case 2:
+        v->info.position[0] = SPA_AUDIO_CHANNEL_FL;
+        v->info.position[1] = SPA_AUDIO_CHANNEL_FR;
+        break;
+    case 1:
+        v->info.position[0] = SPA_AUDIO_CHANNEL_MONO;
+        break;
+    default:
+        for (size_t i = 0; i < v->info.channels; i++) {
+            v->info.position[i] = SPA_AUDIO_CHANNEL_UNKNOWN;
+        }
+        break;
+    }
+
+    /* create a new unconnected pwstream */
+    r = create_stream(c, v, stream_name, name, dir);
+    if (r < 0) {
+        AUD_log(AUDIO_CAP, "Failed to create stream.");
+        return -1;
+    }
+
+    return r;
+}
+
+static int
+qpw_init_out(HWVoiceOut *hw, struct audsettings *as, void *drv_opaque)
+{
+    PWVoiceOut *pw = (PWVoiceOut *) hw;
+    PWVoice *v = &pw->v;
+    struct audsettings obt_as = *as;
+    pwaudio *c = v->g = drv_opaque;
+    AudiodevPipewireOptions *popts = &c->dev->u.pipewire;
+    AudiodevPipewirePerDirectionOptions *ppdo = popts->out;
+    int r;
+
+    pw_thread_loop_lock(c->thread_loop);
+
+    v->info.format = audfmt_to_pw(as->fmt, as->endianness);
+    v->info.channels = as->nchannels;
+    v->info.rate = as->freq;
+
+    obt_as.fmt =
+        pw_to_audfmt(v->info.format, &obt_as.endianness, &v->frame_size);
+    v->frame_size *= as->nchannels;
+
+    v->req = (uint64_t)c->dev->timer_period * v->info.rate
+        * 1 / 2 / 1000000 * v->frame_size;
+
+    /* call the function that creates a new stream for playback */
+    r = qpw_stream_new(c, v, ppdo->stream_name ? : c->dev->id,
+                       ppdo->name, SPA_DIRECTION_OUTPUT);
+    if (r < 0) {
+        error_report("qpw_stream_new for playback failed");
+        pw_thread_loop_unlock(c->thread_loop);
+        return -1;
+    }
+
+    /* report the audio format we support */
+    audio_pcm_init_info(&hw->info, &obt_as);
+
+    /* report the buffer size to qemu */
+    hw->samples = audio_buffer_frames(
+        qapi_AudiodevPipewirePerDirectionOptions_base(ppdo), &obt_as, 46440);
+    v->highwater_mark = MIN(RINGBUFFER_SIZE,
+                            (ppdo->has_latency ? ppdo->latency : 46440)
+                            * (uint64_t)v->info.rate / 1000000 * v->frame_size);
+
+    pw_thread_loop_unlock(c->thread_loop);
+    return 0;
+}
+
+static int
+qpw_init_in(HWVoiceIn *hw, struct audsettings *as, void *drv_opaque)
+{
+    PWVoiceIn *pw = (PWVoiceIn *) hw;
+    PWVoice *v = &pw->v;
+    struct audsettings obt_as = *as;
+    pwaudio *c = v->g = drv_opaque;
+    AudiodevPipewireOptions *popts = &c->dev->u.pipewire;
+    AudiodevPipewirePerDirectionOptions *ppdo = popts->in;
+    int r;
+
+    pw_thread_loop_lock(c->thread_loop);
+
+    v->info.format = audfmt_to_pw(as->fmt, as->endianness);
+    v->info.channels = as->nchannels;
+    v->info.rate = as->freq;
+
+    obt_as.fmt =
+        pw_to_audfmt(v->info.format, &obt_as.endianness, &v->frame_size);
+    v->frame_size *= as->nchannels;
+
+    /* call the function that creates a new stream for recording */
+    r = qpw_stream_new(c, v, ppdo->stream_name ? : c->dev->id,
+                       ppdo->name, SPA_DIRECTION_INPUT);
+    if (r < 0) {
+        error_report("qpw_stream_new for recording failed");
+        pw_thread_loop_unlock(c->thread_loop);
+        return -1;
+    }
+
+    /* report the audio format we support */
+    audio_pcm_init_info(&hw->info, &obt_as);
+
+    /* report the buffer size to qemu */
+    hw->samples = audio_buffer_frames(
+        qapi_AudiodevPipewirePerDirectionOptions_base(ppdo), &obt_as, 46440);
+
+    pw_thread_loop_unlock(c->thread_loop);
+    return 0;
+}
+
+static void
+qpw_fini_out(HWVoiceOut *hw)
+{
+    PWVoiceOut *pw = (PWVoiceOut *) hw;
+    PWVoice *v = &pw->v;
+
+    if (v->stream) {
+        pwaudio *c = v->g;
+        pw_thread_loop_lock(c->thread_loop);
+        pw_stream_destroy(v->stream);
+        v->stream = NULL;
+        pw_thread_loop_unlock(c->thread_loop);
+    }
+}
+
+static void
+qpw_fini_in(HWVoiceIn *hw)
+{
+    PWVoiceIn *pw = (PWVoiceIn *) hw;
+    PWVoice *v = &pw->v;
+
+    if (v->stream) {
+        pwaudio *c = v->g;
+        pw_thread_loop_lock(c->thread_loop);
+        pw_stream_destroy(v->stream);
+        v->stream = NULL;
+        pw_thread_loop_unlock(c->thread_loop);
+    }
+}
+
+static void
+qpw_enable_out(HWVoiceOut *hw, bool enable)
+{
+    PWVoiceOut *po = (PWVoiceOut *) hw;
+    PWVoice *v = &po->v;
+    pwaudio *c = v->g;
+    pw_thread_loop_lock(c->thread_loop);
+    pw_stream_set_active(v->stream, enable);
+    pw_thread_loop_unlock(c->thread_loop);
+}
+
+static void
+qpw_enable_in(HWVoiceIn *hw, bool enable)
+{
+    PWVoiceIn *pi = (PWVoiceIn *) hw;
+    PWVoice *v = &pi->v;
+    pwaudio *c = v->g;
+    pw_thread_loop_lock(c->thread_loop);
+    pw_stream_set_active(v->stream, enable);
+    pw_thread_loop_unlock(c->thread_loop);
+}
+
+static void
+qpw_volume_out(HWVoiceOut *hw, Volume *vol)
+{
+    PWVoiceOut *pw = (PWVoiceOut *) hw;
+    PWVoice *v = &pw->v;
+    pwaudio *c = v->g;
+    int i, ret;
+
+    pw_thread_loop_lock(c->thread_loop);
+    v->volume.channels = vol->channels;
+
+    for (i = 0; i < vol->channels; ++i) {
+        v->volume.values[i] = (float)vol->vol[i] / 255;
+    }
+
+    ret = pw_stream_set_control(v->stream,
+        SPA_PROP_channelVolumes, v->volume.channels, v->volume.values, 0);
+    trace_pw_vol(ret == 0 ? "success" : "failed");
+
+    v->muted = vol->mute;
+    float val = v->muted ? 1.f : 0.f;
+    ret = pw_stream_set_control(v->stream, SPA_PROP_mute, 1, &val, 0);
+    pw_thread_loop_unlock(c->thread_loop);
+}
+
+static void
+qpw_volume_in(HWVoiceIn *hw, Volume *vol)
+{
+    PWVoiceIn *pw = (PWVoiceIn *) hw;
+    PWVoice *v = &pw->v;
+    pwaudio *c = v->g;
+    int i, ret;
+
+    pw_thread_loop_lock(c->thread_loop);
+    v->volume.channels = vol->channels;
+
+    for (i = 0; i < vol->channels; ++i) {
+        v->volume.values[i] = (float)vol->vol[i] / 255;
+    }
+
+    ret = pw_stream_set_control(v->stream,
+        SPA_PROP_channelVolumes, v->volume.channels, v->volume.values, 0);
+    trace_pw_vol(ret == 0 ? "success" : "failed");
+
+    v->muted = vol->mute;
+    float val = v->muted ? 1.f : 0.f;
+    ret = pw_stream_set_control(v->stream, SPA_PROP_mute, 1, &val, 0);
+    pw_thread_loop_unlock(c->thread_loop);
+}
+
+static int wait_resync(pwaudio *pw)
+{
+    int res;
+    pw->pending_seq = pw_core_sync(pw->core, PW_ID_CORE, pw->pending_seq);
+
+    while (true) {
+        pw_thread_loop_wait(pw->thread_loop);
+
+        res = pw->error;
+        if (res < 0) {
+            pw->error = 0;
+            return res;
+        }
+        if (pw->pending_seq == pw->last_seq) {
+            break;
+        }
+    }
+    return 0;
+}
+static void
+on_core_error(void *data, uint32_t id, int seq, int res, const char *message)
+{
+    pwaudio *pw = data;
+
+    error_report("error id:%u seq:%d res:%d (%s): %s",
+                id, seq, res, spa_strerror(res), message);
+
+    /* stop and exit the thread loop */
+    pw_thread_loop_signal(pw->thread_loop, FALSE);
+}
+
+static void
+on_core_done(void *data, uint32_t id, int seq)
+{
+    pwaudio *pw = data;
+    assert(id == PW_ID_CORE);
+    pw->last_seq = seq;
+    if (pw->pending_seq == seq) {
+        /* stop and exit the thread loop */
+        pw_thread_loop_signal(pw->thread_loop, FALSE);
+    }
+}
+
+static const struct pw_core_events core_events = {
+    PW_VERSION_CORE_EVENTS,
+    .done = on_core_done,
+    .error = on_core_error,
+};
+
+static void *
+qpw_audio_init(Audiodev *dev)
+{
+    g_autofree pwaudio *pw = g_new0(pwaudio, 1);
+    pw_init(NULL, NULL);
+
+    trace_pw_audio_init();
+    assert(dev->driver == AUDIODEV_DRIVER_PIPEWIRE);
+
+    pw->dev = dev;
+    pw->thread_loop = pw_thread_loop_new("Pipewire thread loop", NULL);
+    if (pw->thread_loop == NULL) {
+        error_report("Could not create Pipewire loop");
+        goto fail;
+    }
+
+    pw->context =
+        pw_context_new(pw_thread_loop_get_loop(pw->thread_loop), NULL, 0);
+    if (pw->context == NULL) {
+        error_report("Could not create Pipewire context");
+        goto fail;
+    }
+
+    if (pw_thread_loop_start(pw->thread_loop) < 0) {
+        error_report("Could not start Pipewire loop");
+        goto fail;
+    }
+
+    pw_thread_loop_lock(pw->thread_loop);
+
+    pw->core = pw_context_connect(pw->context, NULL, 0);
+    if (pw->core == NULL) {
+        pw_thread_loop_unlock(pw->thread_loop);
+        goto fail;
+    }
+
+    if (pw_core_add_listener(pw->core, &pw->core_listener,
+                             &core_events, pw) < 0) {
+        pw_thread_loop_unlock(pw->thread_loop);
+        goto fail;
+    }
+    if (wait_resync(pw) < 0) {
+        pw_thread_loop_unlock(pw->thread_loop);
+    }
+
+    pw_thread_loop_unlock(pw->thread_loop);
+
+    return g_steal_pointer(&pw);
+
+fail:
+    AUD_log(AUDIO_CAP, "Failed to initialize PW context");
+    if (pw->thread_loop) {
+        pw_thread_loop_stop(pw->thread_loop);
+    }
+    if (pw->context) {
+        g_clear_pointer(&pw->context, pw_context_destroy);
+    }
+    if (pw->thread_loop) {
+        g_clear_pointer(&pw->thread_loop, pw_thread_loop_destroy);
+    }
+    return NULL;
+}
+
+static void
+qpw_audio_fini(void *opaque)
+{
+    pwaudio *pw = opaque;
+
+    if (pw->thread_loop) {
+        pw_thread_loop_stop(pw->thread_loop);
+    }
+
+    if (pw->core) {
+        spa_hook_remove(&pw->core_listener);
+        spa_zero(pw->core_listener);
+        pw_core_disconnect(pw->core);
+    }
+
+    if (pw->context) {
+        pw_context_destroy(pw->context);
+    }
+    pw_thread_loop_destroy(pw->thread_loop);
+
+    g_free(pw);
+}
+
+static struct audio_pcm_ops qpw_pcm_ops = {
+    .init_out = qpw_init_out,
+    .fini_out = qpw_fini_out,
+    .write = qpw_write,
+    .buffer_get_free = qpw_buffer_get_free,
+    .run_buffer_out = audio_generic_run_buffer_out,
+    .enable_out = qpw_enable_out,
+    .volume_out = qpw_volume_out,
+    .volume_in = qpw_volume_in,
+
+    .init_in = qpw_init_in,
+    .fini_in = qpw_fini_in,
+    .read = qpw_read,
+    .run_buffer_in = audio_generic_run_buffer_in,
+    .enable_in = qpw_enable_in
+};
+
+static struct audio_driver pw_audio_driver = {
+    .name = "pipewire",
+    .descr = "http://www.pipewire.org/",
+    .init = qpw_audio_init,
+    .fini = qpw_audio_fini,
+    .pcm_ops = &qpw_pcm_ops,
+    .can_be_default = 1,
+    .max_voices_out = INT_MAX,
+    .max_voices_in = INT_MAX,
+    .voice_size_out = sizeof(PWVoiceOut),
+    .voice_size_in = sizeof(PWVoiceIn),
+};
+
+static void
+register_audio_pw(void)
+{
+    audio_driver_register(&pw_audio_driver);
+}
+
+type_init(register_audio_pw);

audio/trace-events

@@ -18,6 +18,14 @@ dbus_audio_register(const char *s, const char *dir) "sender = %s, dir = %s"
 dbus_audio_put_buffer_out(size_t len) "len = %zu"
 dbus_audio_read(size_t len) "len = %zu"
 
+# pwaudio.c
+pw_state_changed(int nodeid, const char *s) "node id: %d stream state: %s"
+pw_read(int32_t avail, uint32_t index, size_t len) "avail=%d index=%u len=%zu"
+pw_write(int32_t filled, int32_t avail, uint32_t index, size_t len) "filled=%d avail=%d index=%u len=%zu"
+pw_vol(const char *ret) "set volume: %s"
+pw_period(uint64_t quantum, uint32_t rate) "period =%" PRIu64 "/%u"
+pw_audio_init(void) "Initialize Pipewire context"
+
 # audio.c
 audio_timer_start(int interval) "interval %d ms"
 audio_timer_stop(void) ""

meson.build

@@ -734,6 +734,12 @@ if not get_option('jack').auto() or have_system
   jack = dependency('jack', required: get_option('jack'),
                     method: 'pkg-config', kwargs: static_kwargs)
 endif
+pipewire = not_found
+if not get_option('pipewire').auto() or (targetos == 'linux' and have_system)
+  pipewire = dependency('libpipewire-0.3', version: '>=0.3.60',
+                    required: get_option('pipewire'),
+                    method: 'pkg-config', kwargs: static_kwargs)
+endif
 sndio = not_found
 if not get_option('sndio').auto() or have_system
   sndio = dependency('sndio', required: get_option('sndio'),
@@ -1671,6 +1677,7 @@ if have_system
     'jack': jack.found(),
     'oss': oss.found(),
     'pa': pulse.found(),
+    'pipewire': pipewire.found(),
     'sdl': sdl.found(),
     'sndio': sndio.found(),
   }
@@ -3981,6 +3988,7 @@ if targetos == 'linux'
   summary_info += {'ALSA support':    alsa}
   summary_info += {'PulseAudio support': pulse}
 endif
+summary_info += {'Pipewire support':   pipewire}
 summary_info += {'JACK support':      jack}
 summary_info += {'brlapi support':    brlapi}
 summary_info += {'vde support':       vde}

meson_options.txt

@@ -21,7 +21,7 @@ option('tls_priority', type : 'string', value : 'NORMAL',
 option('default_devices', type : 'boolean', value : true,
        description: 'Include a default selection of devices in emulators')
 option('audio_drv_list', type: 'array', value: ['default'],
-       choices: ['alsa', 'coreaudio', 'default', 'dsound', 'jack', 'oss', 'pa', 'sdl', 'sndio'],
+       choices: ['alsa', 'coreaudio', 'default', 'dsound', 'jack', 'oss', 'pa', 'pipewire', 'sdl', 'sndio'],
        description: 'Set audio driver list')
 option('block_drv_rw_whitelist', type : 'string', value : '',
        description: 'set block driver read-write whitelist (by default affects only QEMU, not tools like qemu-img)')
@@ -255,6 +255,8 @@ option('oss', type: 'feature', value: 'auto',
        description: 'OSS sound support')
 option('pa', type: 'feature', value: 'auto',
        description: 'PulseAudio sound support')
+option('pipewire', type: 'feature', value: 'auto',
+       description: 'Pipewire sound support')
 option('sndio', type: 'feature', value: 'auto',
        description: 'sndio sound support')
 

qapi/audio.json

@@ -324,6 +324,47 @@
     '*out':    'AudiodevPaPerDirectionOptions',
     '*server': 'str' } }
 
+##
+# @AudiodevPipewirePerDirectionOptions:
+#
+# Options of the Pipewire backend that are used for both playback and
+# recording.
+#
+# @name: name of the sink/source to use
+#
+# @stream-name: name of the Pipewire stream created by qemu.  Can be
+#               used to identify the stream in Pipewire when you
+#               create multiple Pipewire devices or run multiple qemu
+#               instances (default: audiodev's id)
+#
+# @latency: latency you want Pipewire to achieve in microseconds
+#           (default 46000)
+#
+# Since: 8.1
+##
+{ 'struct': 'AudiodevPipewirePerDirectionOptions',
+  'base': 'AudiodevPerDirectionOptions',
+  'data': {
+    '*name': 'str',
+    '*stream-name': 'str',
+    '*latency': 'uint32' } }
+
+##
+# @AudiodevPipewireOptions:
+#
+# Options of the Pipewire audio backend.
+#
+# @in: options of the capture stream
+#
+# @out: options of the playback stream
+#
+# Since: 8.1
+##
+{ 'struct': 'AudiodevPipewireOptions',
+  'data': {
+    '*in':     'AudiodevPipewirePerDirectionOptions',
+    '*out':    'AudiodevPipewirePerDirectionOptions' } }
+
 ##
 # @AudiodevSdlPerDirectionOptions:
 #
@@ -416,6 +457,7 @@
             { 'name': 'jack', 'if': 'CONFIG_AUDIO_JACK' },
             { 'name': 'oss', 'if': 'CONFIG_AUDIO_OSS' },
             { 'name': 'pa', 'if': 'CONFIG_AUDIO_PA' },
+            { 'name': 'pipewire', 'if': 'CONFIG_AUDIO_PIPEWIRE' },
             { 'name': 'sdl', 'if': 'CONFIG_AUDIO_SDL' },
             { 'name': 'sndio', 'if': 'CONFIG_AUDIO_SNDIO' },
             { 'name': 'spice', 'if': 'CONFIG_SPICE' },
@@ -456,6 +498,8 @@
                    'if': 'CONFIG_AUDIO_OSS' },
     'pa':        { 'type': 'AudiodevPaOptions',
                    'if': 'CONFIG_AUDIO_PA' },
+    'pipewire':  { 'type': 'AudiodevPipewireOptions',
+                   'if': 'CONFIG_AUDIO_PIPEWIRE' },
     'sdl':       { 'type': 'AudiodevSdlOptions',
                    'if': 'CONFIG_AUDIO_SDL' },
     'sndio':     { 'type': 'AudiodevSndioOptions',

qemu-options.hx

@@ -793,6 +793,12 @@ DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev,
     "                in|out.name= source/sink device name\n"
     "                in|out.latency= desired latency in microseconds\n"
 #endif
+#ifdef CONFIG_AUDIO_PIPEWIRE
+    "-audiodev pipewire,id=id[,prop[=value][,...]]\n"
+    "                in|out.name= source/sink device name\n"
+    "                in|out.stream-name= name of pipewire stream\n"
+    "                in|out.latency= desired latency in microseconds\n"
+#endif
 #ifdef CONFIG_AUDIO_SDL
     "-audiodev sdl,id=id[,prop[=value][,...]]\n"
     "                in|out.buffer-count= number of buffers\n"
@@ -956,6 +962,21 @@ SRST
         Desired latency in microseconds. The PulseAudio server will try
         to honor this value but actual latencies may be lower or higher.
 
+``-audiodev pipewire,id=id[,prop[=value][,...]]``
+    Creates a backend using Pipewire. This backend is available on
+    most systems.
+
+    Pipewire specific options are:
+
+    ``in|out.latency=usecs``
+        Desired latency in microseconds.
+
+    ``in|out.name=sink``
+        Use the specified source/sink for recording/playback.
+
+    ``in|out.stream-name``
+        Specify the name of pipewire stream.
+
 ``-audiodev sdl,id=id[,prop[=value][,...]]``
     Creates a backend using SDL. This backend is available on most
     systems, but you should use your platform's native backend if

scripts/meson-buildoptions.sh

@@ -1,7 +1,8 @@
 # This file is generated by meson-buildoptions.py, do not edit!
 meson_options_help() {
-  printf "%s\n" '  --audio-drv-list=CHOICES Set audio driver list [default] (choices: alsa/co'
-  printf "%s\n" '                           reaudio/default/dsound/jack/oss/pa/sdl/sndio)'
+  printf "%s\n" '  --audio-drv-list=CHOICES Set audio driver list [default] (choices: al'
+  printf "%s\n" '                           sa/coreaudio/default/dsound/jack/oss/pa/'
+  printf "%s\n" '                           pipewire/sdl/sndio)'
   printf "%s\n" '  --block-drv-ro-whitelist=VALUE'
   printf "%s\n" '                           set block driver read-only whitelist (by default'
   printf "%s\n" '                           affects only QEMU, not tools like qemu-img)'
@@ -136,6 +137,7 @@ meson_options_help() {
   printf "%s\n" '  oss             OSS sound support'
   printf "%s\n" '  pa              PulseAudio sound support'
   printf "%s\n" '  parallels       parallels image format support'
+  printf "%s\n" '  pipewire        Pipewire sound support'
   printf "%s\n" '  png             PNG support with libpng'
   printf "%s\n" '  pvrdma          Enable PVRDMA support'
   printf "%s\n" '  qcow1           qcow1 image format support'
@@ -370,6 +372,8 @@ _meson_option_parse() {
     --disable-pa) printf "%s" -Dpa=disabled ;;
     --enable-parallels) printf "%s" -Dparallels=enabled ;;
     --disable-parallels) printf "%s" -Dparallels=disabled ;;
+    --enable-pipewire) printf "%s" -Dpipewire=enabled ;;
+    --disable-pipewire) printf "%s" -Dpipewire=disabled ;;
     --with-pkgversion=*) quote_sh "-Dpkgversion=$2" ;;
     --enable-png) printf "%s" -Dpng=enabled ;;
     --disable-png) printf "%s" -Dpng=disabled ;;