Add PipeWire audio backend

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Merge tag 'pw-pull-request' of https://gitlab.com/marcandre.lureau/qemu into staging

Add PipeWire audio backend

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# gpg: Signature made Fri 05 May 2023 12:37:27 PM BST
# gpg:                using RSA key 87A9BD933F87C606D276F62DDAE8E10975969CE5
# gpg:                issuer "marcandre.lureau@redhat.com"
# gpg: Good signature from "Marc-André Lureau <marcandre.lureau@redhat.com>" [full]
# gpg:                 aka "Marc-André Lureau <marcandre.lureau@gmail.com>" [full]

* tag 'pw-pull-request' of https://gitlab.com/marcandre.lureau/qemu:
  audio/pwaudio.c: Add Pipewire audio backend for QEMU

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

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" '  --audio-drv-list=CHOICES Set audio driver list [default] (choices: al'
-  printf "%s\n" '                           reaudio/default/dsound/jack/oss/pa/sdl/sndio)'
+  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 ;;