* [PATCH v11 01/14] ALSA: virtio: Propagate PCM send failures through ACK
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:29 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 02/14] ALSA: virtio: Recover PCM state after a failed start Joonho Lee
` (12 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
virtsnd_pcm_msg_send() can fail while queueing a transfer. Restore the
failed message's length and notify the device about earlier messages
queued by the same call, so they do not remain stranded.
Propagate that failure through the indirect PCM transfer callback instead
of discarding it. Commit the updated indirect state only after successful
submission and stop further transfers when a send fails. Return an XRUN
error to ALSA so the stream can recover.
Keep the polling feature path unchanged.
Fixes: fe981e67568c ("ALSA: virtio: use ack callback")
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/virtio/virtio_pcm_msg.c b/sound/virtio/virtio_pcm_msg.c
--- a/sound/virtio/virtio_pcm_msg.c
+++ b/sound/virtio/virtio_pcm_msg.c
@@ -260,6 +260,18 @@
dev_err(&vdev->dev,
"SID %u: failed to send I/O message\n",
vss->sid);
+ msg->length -= n;
+
+ /*
+ * Do not leave earlier messages queued without notifying
+ * the device when a later message could not be added.
+ */
+ if (msg_count != vss->msg_count &&
+ !(vss->features &
+ (1U << VIRTIO_SND_PCM_F_MSG_POLLING)) &&
+ virtqueue_kick_prepare(vqueue))
+ virtqueue_notify(vqueue);
+
return rc;
}
diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
--- a/sound/virtio/virtio_pcm_ops.c
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -466,36 +466,100 @@
vss->hw_ptr);
}
+struct virtsnd_pcm_transfer {
+ struct snd_pcm_indirect indirect;
+ int error;
+};
+
static void virtsnd_pcm_trans_copy(struct snd_pcm_substream *substream,
struct snd_pcm_indirect *rec, size_t bytes)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
-
- virtsnd_pcm_msg_send(vss, rec->sw_data, bytes);
+ struct virtsnd_pcm_transfer *transfer =
+ container_of(rec, struct virtsnd_pcm_transfer, indirect);
+
+ if (transfer->error)
+ return;
+
+ transfer->error = virtsnd_pcm_msg_send(vss, rec->sw_data, bytes);
+}
+
+/* Caller holds vss->lock. */
+static void virtsnd_pcm_transfer_failed(struct virtio_pcm_substream *vss)
+{
+ vss->xfer_enabled = false;
+ vss->stopped = true;
+ vss->substream->runtime->stop_operating = true;
}
static int virtsnd_pcm_pb_ack(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
-
- guard(spinlock_irqsave)(&queue->lock);
- guard(spinlock)(&vss->lock);
-
- return snd_pcm_indirect_playback_transfer(substream, &vss->pcm_indirect,
- virtsnd_pcm_trans_copy);
+ struct virtsnd_pcm_transfer transfer = {};
+ int rc;
+
+ scoped_guard(spinlock_irqsave, &queue->lock) {
+ guard(spinlock)(&vss->lock);
+ transfer.indirect = vss->pcm_indirect;
+ if (vss->stopped) {
+ rc = -EPIPE;
+ } else {
+ rc = snd_pcm_indirect_playback_transfer(substream,
+ &transfer.indirect,
+ virtsnd_pcm_trans_copy);
+ }
+ if (!rc)
+ rc = transfer.error;
+ if (rc)
+ virtsnd_pcm_transfer_failed(vss);
+ else
+ vss->pcm_indirect = transfer.indirect;
+ }
+ if (rc) {
+ dev_err(&vss->snd->vdev->dev,
+ "SID %u: playback ACK transfer failed: %d\n",
+ vss->sid, rc);
+ /* ALSA treats -EPIPE as an XRUN in ACK and pointer paths. */
+ return -EPIPE;
+ }
+
+ return 0;
}
static int virtsnd_pcm_cp_ack(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
-
- guard(spinlock_irqsave)(&queue->lock);
- guard(spinlock)(&vss->lock);
-
- return snd_pcm_indirect_capture_transfer(substream, &vss->pcm_indirect,
- virtsnd_pcm_trans_copy);
+ struct virtsnd_pcm_transfer transfer = {};
+ int rc;
+
+ scoped_guard(spinlock_irqsave, &queue->lock) {
+ guard(spinlock)(&vss->lock);
+ transfer.indirect = vss->pcm_indirect;
+ if (vss->stopped) {
+ rc = -EPIPE;
+ } else {
+ rc = snd_pcm_indirect_capture_transfer(substream,
+ &transfer.indirect,
+ virtsnd_pcm_trans_copy);
+ }
+ if (!rc)
+ rc = transfer.error;
+ if (rc)
+ virtsnd_pcm_transfer_failed(vss);
+ else
+ vss->pcm_indirect = transfer.indirect;
+ }
+ if (rc) {
+ dev_err(&vss->snd->vdev->dev,
+ "SID %u: capture ACK transfer failed: %d\n",
+ vss->sid, rc);
+ /* ALSA treats -EPIPE as an XRUN in ACK and pointer paths. */
+ return -EPIPE;
+ }
+
+ return 0;
}
/* PCM substream operators map. */
^ permalink raw reply [flat|nested] 29+ messages in thread* [PATCH v11 02/14] ALSA: virtio: Recover PCM state after a failed start
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
2026-10-31 2:08 ` [PATCH v11 01/14] ALSA: virtio: Propagate PCM send failures through ACK Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:31 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 03/14] ALSA: virtio: Retain queued messages through device reset Joonho Lee
` (11 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Capture trigger queues I/O messages before PCM_START. If the START
message cannot be allocated or sent, transfers may remain queued, and
ALSA does not invoke the action undo callback for the failed trigger.
Mark the stream stopped and disable transfers for every failed START
path. Arm runtime->stop_operating so sync_stop releases pending I/O and
prevents prepare, hw_params, or START retries until release succeeds.
The stopped flag is shared with ACK callbacks that can run without the
ALSA stream lock. Protect every stopped access with vss->lock. Read the
pending message count under the same lock in open and hw_params. In
sync_stop, decide whether RELEASE is needed and mark the stream stopped
in one locked transition; leave it stopped when release or draining fails.
Always cancel elapsed-period work in sync_stop, even when no RELEASE
is needed.
Record the RELEASE obligation after successful PREPARE and clear it as
soon as RELEASE succeeds. If the subsequent RX wait fails, retry that
wait without submitting RELEASE again.
Fixes: da76e9f3e43a ("ALSA: virtio: PCM substream operators")
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h
--- a/sound/virtio/virtio_pcm.h
+++ b/sound/virtio/virtio_pcm.h
@@ -26,13 +26,13 @@
* @hw: Kernel ALSA substream hardware descriptor.
* @elapsed_period: Kernel work to handle the elapsed period state.
* @lock: Spinlock that protects fields shared by interrupt handlers and
- * substream operators.
+ * substream operators, including @stopped.
* @buffer_bytes: Current buffer size in bytes.
* @hw_ptr: Substream hardware pointer value in bytes [0 ... buffer_bytes).
* @xfer_enabled: Data transfer state (0 - off, 1 - on).
* @xfer_xrun: Data underflow/overflow state (0 - no xrun, 1 - xrun).
* @stopped: True if the substream is stopped and must be released on the device
- * side.
+ * side; protected by @lock.
* @suspended: True if the substream is suspended and must be reconfigured on
* the device side at resume.
* @msgs: Allocated I/O messages.
@@ -56,6 +56,8 @@
bool xfer_enabled;
bool xfer_xrun;
bool stopped;
+ /* Successful PREPARE still needs RELEASE; protected by lock. */
+ bool release_required;
bool suspended;
struct virtio_pcm_msg **msgs;
unsigned int nmsgs;
diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
--- a/sound/virtio/virtio_pcm_ops.c
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -96,6 +96,15 @@
static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream);
+static void virtsnd_pcm_start_failed(struct virtio_pcm_substream *vss)
+{
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->xfer_enabled = false;
+ vss->stopped = true;
+ }
+ vss->substream->runtime->stop_operating = true;
+}
+
/**
* virtsnd_pcm_open() - Open the PCM substream.
* @substream: Kernel ALSA substream.
@@ -115,7 +124,8 @@
snd_pcm_hw_constraint_integer(substream->runtime,
SNDRV_PCM_HW_PARAM_PERIODS);
- vss->stopped = !!virtsnd_pcm_msg_pending_num(vss);
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ vss->stopped |= !!vss->msg_count;
vss->suspended = false;
/*
@@ -217,11 +227,23 @@
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct virtio_device *vdev = vss->snd->vdev;
+ unsigned int msg_count;
+ bool stopped;
int rc;
- if (virtsnd_pcm_msg_pending_num(vss)) {
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ msg_count = vss->msg_count;
+ stopped = vss->stopped;
+ }
+ if (msg_count) {
dev_err(&vdev->dev, "SID %u: invalid I/O queue state\n",
vss->sid);
+ return -EBADFD;
+ }
+ if (stopped) {
+ dev_err(&vdev->dev, "SID %u: stream release failed\n",
+ vss->sid);
+ substream->runtime->stop_operating = true;
return -EBADFD;
}
@@ -273,6 +295,17 @@
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct virtio_device *vdev = vss->snd->vdev;
struct virtio_snd_msg *msg;
+ bool stopped;
+ int rc;
+
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ stopped = vss->stopped;
+ if (stopped) {
+ dev_err(&vdev->dev, "SID %u: stream release failed\n",
+ vss->sid);
+ substream->runtime->stop_operating = true;
+ return -EBADFD;
+ }
if (!vss->suspended) {
if (virtsnd_pcm_msg_pending_num(vss)) {
@@ -311,7 +344,12 @@
if (!msg)
return -ENOMEM;
- return virtsnd_ctl_msg_send_sync(vss->snd, msg);
+ rc = virtsnd_ctl_msg_send_sync(vss->snd, msg);
+ if (!rc) {
+ guard(spinlock_irqsave)(&vss->lock);
+ vss->release_required = true;
+ }
+ return rc;
}
/**
@@ -338,31 +376,40 @@
scoped_guard(spinlock_irqsave, &queue->lock) {
guard(spinlock)(&vss->lock);
+ if (vss->stopped) {
+ substream->runtime->stop_operating = true;
+ return -EBADFD;
+ }
if (vss->direction == SNDRV_PCM_STREAM_CAPTURE)
rc = virtsnd_pcm_msg_send(vss, 0, vss->buffer_bytes);
- if (rc)
+ if (rc) {
+ vss->stopped = true;
+ substream->runtime->stop_operating = true;
return rc;
+ }
vss->xfer_enabled = true;
}
msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_START,
GFP_KERNEL);
if (!msg) {
- guard(spinlock_irqsave)(&vss->lock);
- vss->xfer_enabled = false;
-
+ virtsnd_pcm_start_failed(vss);
return -ENOMEM;
}
- return virtsnd_ctl_msg_send_sync(snd, msg);
+ rc = virtsnd_ctl_msg_send_sync(snd, msg);
+ if (rc)
+ virtsnd_pcm_start_failed(vss);
+
+ return rc;
case SNDRV_PCM_TRIGGER_SUSPEND:
vss->suspended = true;
fallthrough;
case SNDRV_PCM_TRIGGER_STOP:
- vss->stopped = true;
- fallthrough;
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (command != SNDRV_PCM_TRIGGER_PAUSE_PUSH)
+ vss->stopped = true;
vss->xfer_enabled = false;
}
@@ -393,21 +440,34 @@
struct virtio_snd *snd = vss->snd;
struct virtio_snd_msg *msg;
unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
+ bool need_release;
int rc;
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->xfer_enabled = false;
+ need_release = vss->release_required;
+ if (need_release)
+ vss->stopped = true;
+ }
cancel_work_sync(&vss->elapsed_period);
- if (!vss->stopped)
- return 0;
-
- msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_RELEASE,
- GFP_KERNEL);
- if (!msg)
- return -ENOMEM;
-
- rc = virtsnd_ctl_msg_send_sync(snd, msg);
- if (rc)
- return rc;
+ if (need_release) {
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_RELEASE,
+ GFP_KERNEL);
+ if (!msg) {
+ substream->runtime->stop_operating = true;
+ return -ENOMEM;
+ }
+
+ rc = virtsnd_ctl_msg_send_sync(snd, msg);
+ if (rc) {
+ substream->runtime->stop_operating = true;
+ return rc;
+ }
+
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ vss->release_required = false;
+ }
/*
* The spec states that upon receipt of the RELEASE command "the device
@@ -421,11 +481,13 @@
if (rc <= 0) {
dev_warn(&snd->vdev->dev, "SID %u: failed to flush I/O queue\n",
vss->sid);
+ substream->runtime->stop_operating = true;
return !rc ? -ETIMEDOUT : rc;
}
- vss->stopped = false;
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ vss->stopped = false;
return 0;
}
^ permalink raw reply [flat|nested] 29+ messages in thread* Re: [PATCH v11 02/14] ALSA: virtio: Recover PCM state after a failed start
2026-10-31 2:08 ` [PATCH v11 02/14] ALSA: virtio: Recover PCM state after a failed start Joonho Lee
@ 2026-10-31 2:31 ` sashiko-bot
0 siblings, 0 replies; 29+ messages in thread
From: sashiko-bot @ 2026-10-31 2:31 UTC (permalink / raw)
To: Joonho Lee; +Cc: virtualization, Michael S. Tsirkin, Eugenio Perez
> Capture trigger queues I/O messages before PCM_START. If the START
> message cannot be allocated or sent, transfers may remain queued, and
> ALSA does not invoke the action undo callback for the failed trigger.
>
> Mark the stream stopped and disable transfers for every failed START
> path. Arm runtime->stop_operating so sync_stop releases pending I/O and
> prevents prepare, hw_params, or START retries until release succeeds.
>
> The stopped flag is shared with ACK callbacks that can run without the
> ALSA stream lock. Protect every stopped access with vss->lock. Read the
> pending message count under the same lock in open and hw_params. In
> sync_stop, decide whether RELEASE is needed and mark the stream stopped
> in one locked transition; leave it stopped when release or draining fails.
>
> Always cancel elapsed-period work in sync_stop, even when no RELEASE
> is needed.
>
> Record the RELEASE obligation after successful PREPARE and clear it as
> soon as RELEASE succeeds. If the subsequent RX wait fails, retry that
> wait without submitting RELEASE again.
>
> Fixes: da76e9f3e43a ("ALSA: virtio: PCM substream operators")
> Assisted-by: LLM
> Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261031020855.2402-1-mynameisjune111@gmail.com?part=2
^ permalink raw reply [flat|nested] 29+ messages in thread
* [PATCH v11 03/14] ALSA: virtio: Retain queued messages through device reset
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
2026-10-31 2:08 ` [PATCH v11 01/14] ALSA: virtio: Propagate PCM send failures through ACK Joonho Lee
2026-10-31 2:08 ` [PATCH v11 02/14] ALSA: virtio: Recover PCM state after a failed start Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:40 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 04/14] ALSA: virtio: Keep PCM DMA buffers alive through device ownership Joonho Lee
` (10 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Keep the control queue available through snd_card_free() so close-time
STOP and RELEASE commands can still be submitted. Block new control
requests and mark pending messages canceled before reset, then release
their queue references only after reset and queue deletion.
For PCM queues, detach each remaining virtqueue buffer after the device
has stopped DMA and retire its message without reporting a normal
completion. Detach all queues before deleting them so outstanding DMA
mappings are unmapped and no token remains for a late device completion.
Clear each queue wrapper inside the same critical section that detaches
its buffers. Check the callback's queue identity under the wrapper lock
for PCM, control and event queues. This makes queue retirement explicit
through teardown and restore. A forced callback test passed on both
versions; the proposed detached-ring IRQ failure was not reproduced on
the tested PCI transport.
Fixes: 9d45e514da88 ("ALSA: virtio: handling control messages")
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/virtio/virtio_card.c b/sound/virtio/virtio_card.c
--- a/sound/virtio/virtio_card.c
+++ b/sound/virtio/virtio_card.c
@@ -87,6 +87,8 @@
u32 length;
guard(spinlock_irqsave)(&queue->lock);
+ if (queue->vqueue != vqueue)
+ return;
do {
virtqueue_disable_cb(vqueue);
while ((event = virtqueue_get_buf(vqueue, &length))) {
@@ -338,6 +340,38 @@
}
/**
+ * virtsnd_reset_vqs() - Stop device access and unmap outstanding buffers.
+ * @snd: VirtIO sound device.
+ *
+ * Context: Any context that permits to sleep.
+ */
+static void virtsnd_reset_vqs(struct virtio_snd *snd)
+{
+ struct virtio_device *vdev = snd->vdev;
+ unsigned int i;
+
+ virtio_reset_device(vdev);
+
+ /* Deleting a virtqueue does not unmap its outstanding descriptors. */
+ for (i = 0; i < VIRTIO_SND_VQ_MAX; ++i) {
+ struct virtio_snd_queue *queue = &snd->queues[i];
+ unsigned long flags;
+ void *msg;
+
+ spin_lock_irqsave(&queue->lock, flags);
+ if (queue->vqueue)
+ while ((msg = virtqueue_detach_unused_buf(queue->vqueue)))
+ if (i == VIRTIO_SND_VQ_TX || i == VIRTIO_SND_VQ_RX)
+ virtsnd_pcm_msg_cancel(msg);
+ /* IRQ callbacks must never see a detached ring as live. */
+ queue->vqueue = NULL;
+ spin_unlock_irqrestore(&queue->lock, flags);
+ }
+
+ vdev->config->del_vqs(vdev);
+}
+
+/**
* virtsnd_remove() - Remove VirtIO and ALSA devices.
* @vdev: VirtIO parent device.
*
@@ -349,13 +383,14 @@
unsigned int i;
virtsnd_disable_event_vq(snd);
- virtsnd_ctl_msg_cancel_all(snd);
if (snd->card)
snd_card_free(snd->card);
- virtio_reset_device(vdev);
- vdev->config->del_vqs(vdev);
+ virtsnd_ctl_msg_cancel_all(snd);
+
+ virtsnd_reset_vqs(snd);
+ virtsnd_ctl_msg_cleanup(snd);
for (i = 0; snd->substreams && i < snd->nsubstreams; ++i) {
struct virtio_pcm_substream *vss = &snd->substreams[i];
@@ -383,8 +418,8 @@
virtsnd_disable_event_vq(snd);
virtsnd_ctl_msg_cancel_all(snd);
- virtio_reset_device(vdev);
- vdev->config->del_vqs(vdev);
+ virtsnd_reset_vqs(snd);
+ virtsnd_ctl_msg_cleanup(snd);
for (i = 0; i < snd->nsubstreams; ++i)
cancel_work_sync(&snd->substreams[i].elapsed_period);
@@ -412,6 +447,7 @@
return rc;
virtio_device_ready(vdev);
+ virtsnd_ctl_msg_enable(snd);
virtsnd_enable_event_vq(snd);
diff --git a/sound/virtio/virtio_card.h b/sound/virtio/virtio_card.h
--- a/sound/virtio/virtio_card.h
+++ b/sound/virtio/virtio_card.h
@@ -47,6 +47,7 @@
* @queues: Virtqueue wrappers.
* @card: ALSA sound card.
* @ctl_msgs: Pending control request list.
+ * @ctl_msgs_blocked: Control requests are blocked during teardown or suspend.
* @event_msgs: Device events.
* @pcm_list: VirtIO PCM device list.
* @jacks: VirtIO jacks.
@@ -64,6 +65,7 @@
struct virtio_snd_queue queues[VIRTIO_SND_VQ_MAX];
struct snd_card *card;
struct list_head ctl_msgs;
+ bool ctl_msgs_blocked;
struct virtio_snd_event *event_msgs;
struct list_head pcm_list;
struct virtio_jack *jacks;
diff --git a/sound/virtio/virtio_ctl_msg.c b/sound/virtio/virtio_ctl_msg.c
--- a/sound/virtio/virtio_ctl_msg.c
+++ b/sound/virtio/virtio_ctl_msg.c
@@ -15,6 +15,7 @@
* @list: Pending message list entry.
* @notify: Request completed notification.
* @ref_count: Reference count used to manage a message lifetime.
+ * @cancelled: Request canceled during device teardown.
*/
struct virtio_snd_msg {
struct scatterlist sg_request;
@@ -22,6 +23,7 @@
struct list_head list;
struct completion notify;
refcount_t ref_count;
+ bool cancelled;
};
/**
@@ -100,7 +102,7 @@
INIT_LIST_HEAD(&msg->list);
init_completion(&msg->notify);
- /* This reference is dropped in virtsnd_ctl_msg_complete(). */
+ /* The caller owns this reference; send adds a queue reference. */
refcount_set(&msg->ref_count, 1);
return msg;
@@ -134,6 +136,7 @@
int rc;
virtsnd_ctl_msg_ref(msg);
+ /* This reference stays with the queue until completion or teardown. */
/* Set the default status in case the message was canceled. */
response->code = cpu_to_le32(VIRTIO_SND_S_IO_ERR);
@@ -147,12 +150,17 @@
psgs[nouts + nins++] = in_sgs;
scoped_guard(spinlock_irqsave, &queue->lock) {
- rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins, msg,
- GFP_ATOMIC);
+ if (snd->ctl_msgs_blocked)
+ rc = -ENODEV;
+ else
+ rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins,
+ msg, GFP_ATOMIC);
if (!rc) {
notify = virtqueue_kick_prepare(queue->vqueue);
list_add_tail(&msg->list, &snd->ctl_msgs);
+ if (notify)
+ virtqueue_notify(queue->vqueue);
}
}
@@ -168,9 +176,6 @@
goto on_exit;
}
-
- if (notify)
- virtqueue_notify(queue->vqueue);
if (nowait)
goto on_exit;
@@ -184,6 +189,11 @@
rc = -ETIMEDOUT;
}
+ goto on_exit;
+ }
+
+ if (READ_ONCE(msg->cancelled)) {
+ rc = -ENODEV;
goto on_exit;
}
@@ -227,9 +237,33 @@
* virtsnd_ctl_msg_cancel_all() - Cancel all pending control messages.
* @snd: VirtIO sound device.
*
- * Context: Any context.
+ * Context: Any context. Blocks new senders and marks pending requests canceled.
+ * Existing senders are woken when their request completes or after
+ * the device has been reset.
*/
void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd)
+{
+ struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
+ struct virtio_snd_msg *msg;
+
+ guard(spinlock_irqsave)(&queue->lock);
+ snd->ctl_msgs_blocked = true;
+ list_for_each_entry(msg, &snd->ctl_msgs, list) {
+ WRITE_ONCE(msg->cancelled, true);
+ }
+}
+
+/**
+ * virtsnd_ctl_msg_cleanup() - Release messages left after queue teardown.
+ * @snd: VirtIO sound device.
+ *
+ * This must be called after device reset, buffer detachment, and del_vqs(),
+ * when no queue callback or DMA access can still reach a message. The queue
+ * object and its lock must remain alive until this function returns.
+ *
+ * Context: Any context.
+ */
+void virtsnd_ctl_msg_cleanup(struct virtio_snd *snd)
{
struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
@@ -244,6 +278,20 @@
}
/**
+ * virtsnd_ctl_msg_enable() - Allow control requests after queue restoration.
+ * @snd: VirtIO sound device.
+ *
+ * Context: Any context.
+ */
+void virtsnd_ctl_msg_enable(struct virtio_snd *snd)
+{
+ struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
+
+ guard(spinlock_irqsave)(&queue->lock);
+ snd->ctl_msgs_blocked = false;
+}
+
+/**
* virtsnd_ctl_query_info() - Query the item configuration from the device.
* @snd: VirtIO sound device.
* @command: Control request code (VIRTIO_SND_R_XXX_INFO).
@@ -295,6 +343,8 @@
u32 length;
guard(spinlock_irqsave)(&queue->lock);
+ if (queue->vqueue != vqueue)
+ return;
do {
virtqueue_disable_cb(vqueue);
while ((msg = virtqueue_get_buf(vqueue, &length)))
diff --git a/sound/virtio/virtio_ctl_msg.h b/sound/virtio/virtio_ctl_msg.h
--- a/sound/virtio/virtio_ctl_msg.h
+++ b/sound/virtio/virtio_ctl_msg.h
@@ -68,6 +68,10 @@
void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd);
+void virtsnd_ctl_msg_cleanup(struct virtio_snd *snd);
+
+void virtsnd_ctl_msg_enable(struct virtio_snd *snd);
+
void virtsnd_ctl_msg_complete(struct virtio_snd_msg *msg);
int virtsnd_ctl_query_info(struct virtio_snd *snd, int command, int start_id,
diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h
--- a/sound/virtio/virtio_pcm.h
+++ b/sound/virtio/virtio_pcm.h
@@ -122,6 +122,8 @@
void virtsnd_pcm_msg_reset(struct virtio_pcm_substream *vss);
+void virtsnd_pcm_msg_cancel(struct virtio_pcm_msg *msg);
+
int virtsnd_pcm_msg_send(struct virtio_pcm_substream *vss, unsigned long offset,
unsigned long bytes);
diff --git a/sound/virtio/virtio_pcm_msg.c b/sound/virtio/virtio_pcm_msg.c
--- a/sound/virtio/virtio_pcm_msg.c
+++ b/sound/virtio/virtio_pcm_msg.c
@@ -305,6 +305,35 @@
{
guard(spinlock_irqsave)(&vss->lock);
return vss->msg_count;
+}
+
+/**
+ * virtsnd_pcm_msg_cancel() - Cancel a message detached during device reset.
+ * @msg: Message returned by virtqueue_detach_unused_buf().
+ *
+ * Reset cancellation retires the queue token without treating it as a device
+ * completion. In particular, it does not advance the PCM hardware pointer or
+ * schedule period work.
+ *
+ * Context: Process context with the PCM queue lock held.
+ */
+void virtsnd_pcm_msg_cancel(struct virtio_pcm_msg *msg)
+{
+ struct virtio_pcm_substream *vss = msg->substream;
+ bool wake;
+
+ {
+ guard(spinlock)(&vss->lock);
+ msg->length = 0;
+ vss->xfer_enabled = false;
+ if (WARN_ON_ONCE(!vss->msg_count))
+ return;
+ vss->msg_count--;
+ wake = !vss->msg_count;
+ }
+
+ if (wake)
+ wake_up_all(&vss->msg_empty);
}
/**
@@ -367,16 +396,21 @@
/**
* virtsnd_pcm_notify_cb() - Process all completed I/O messages.
- * @queue: Underlying tx/rx virtqueue.
+ * @queue: Underlying tx/rx queue wrapper.
+ * @vqueue: Queue that raised this callback.
*
* Context: Interrupt context. Takes and releases the tx/rx queue spinlock.
*/
-static inline void virtsnd_pcm_notify_cb(struct virtio_snd_queue *queue)
+static inline void
+virtsnd_pcm_notify_cb(struct virtio_snd_queue *queue, struct virtqueue *vqueue)
{
struct virtio_pcm_msg *msg;
u32 written_bytes;
guard(spinlock_irqsave)(&queue->lock);
+ /* Reset can detach the queue before the transport drains its IRQs. */
+ if (queue->vqueue != vqueue)
+ return;
do {
virtqueue_disable_cb(queue->vqueue);
while ((msg = virtqueue_get_buf(queue->vqueue, &written_bytes)))
@@ -394,7 +428,7 @@
{
struct virtio_snd *snd = vqueue->vdev->priv;
- virtsnd_pcm_notify_cb(virtsnd_tx_queue(snd));
+ virtsnd_pcm_notify_cb(virtsnd_tx_queue(snd), vqueue);
}
/**
@@ -407,7 +441,7 @@
{
struct virtio_snd *snd = vqueue->vdev->priv;
- virtsnd_pcm_notify_cb(virtsnd_rx_queue(snd));
+ virtsnd_pcm_notify_cb(virtsnd_rx_queue(snd), vqueue);
}
/**
^ permalink raw reply [flat|nested] 29+ messages in thread* Re: [PATCH v11 03/14] ALSA: virtio: Retain queued messages through device reset
2026-10-31 2:08 ` [PATCH v11 03/14] ALSA: virtio: Retain queued messages through device reset Joonho Lee
@ 2026-10-31 2:40 ` sashiko-bot
0 siblings, 0 replies; 29+ messages in thread
From: sashiko-bot @ 2026-10-31 2:40 UTC (permalink / raw)
To: Joonho Lee; +Cc: virtualization, Michael S. Tsirkin, Eugenio Perez
> Keep the control queue available through snd_card_free() so close-time
> STOP and RELEASE commands can still be submitted. Block new control
> requests and mark pending messages canceled before reset, then release
> their queue references only after reset and queue deletion.
>
> For PCM queues, detach each remaining virtqueue buffer after the device
> has stopped DMA and retire its message without reporting a normal
> completion. Detach all queues before deleting them so outstanding DMA
> mappings are unmapped and no token remains for a late device completion.
>
> Clear each queue wrapper inside the same critical section that detaches
> its buffers. Check the callback's queue identity under the wrapper lock
> for PCM, control and event queues. This makes queue retirement explicit
> through teardown and restore. A forced callback test passed on both
> versions; the proposed detached-ring IRQ failure was not reproduced on
> the tested PCI transport.
>
> Fixes: 9d45e514da88 ("ALSA: virtio: handling control messages")
> Assisted-by: LLM
> Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261031020855.2402-1-mynameisjune111@gmail.com?part=3
^ permalink raw reply [flat|nested] 29+ messages in thread
* [PATCH v11 04/14] ALSA: virtio: Keep PCM DMA buffers alive through device ownership
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (2 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 03/14] ALSA: virtio: Retain queued messages through device reset Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:33 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 05/14] ALSA: virtio: Keep control payloads alive through DMA completion Joonho Lee
` (9 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Retain references to the pages backing ALSA's vmalloc buffer until its
queued I/O messages are freed. On NOMMU systems, use driver-owned memory
for DMA and copy playback data before submission and capture data after
completion, so ALSA buffer release cannot invalidate an active request.
Validate the PCM buffer and each period before building scatterlists.
Clamp device-reported capture lengths to the message capacity before
advancing the hardware pointer, preventing an oversized completion from
accounting bytes beyond the buffer actually submitted.
Require whole-byte periods whose total matches the negotiated buffer.
Check offset, length and the final message index before indexing the
message array, including empty transfers and arithmetic wraparound.
Seed the ordinary capture ring once per prepare. Native STOP preserves
queued requests and unread samples, so PAUSE_RELEASE must retain their
ownership. Re-enqueuing the entire ring adds another period to pending
message lengths and exposes unread DMA slots to the device. Return
consumed space through the existing indirect ACK path.
Fixes: f40a28679e0b ("ALSA: virtio: handling control and I/O messages for the PCM device")
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h
--- a/sound/virtio/virtio_pcm.h
+++ b/sound/virtio/virtio_pcm.h
@@ -13,6 +13,7 @@
struct virtio_pcm;
struct virtio_pcm_msg;
+struct page;
/**
* struct virtio_pcm_substream - VirtIO PCM substream.
@@ -29,6 +30,7 @@
* substream operators, including @stopped.
* @buffer_bytes: Current buffer size in bytes.
* @hw_ptr: Substream hardware pointer value in bytes [0 ... buffer_bytes).
+ * @capture_rx_seeded: Ordinary capture ring was queued since prepare.
* @xfer_enabled: Data transfer state (0 - off, 1 - on).
* @xfer_xrun: Data underflow/overflow state (0 - no xrun, 1 - xrun).
* @stopped: True if the substream is stopped and must be released on the device
@@ -38,6 +40,10 @@
* @msgs: Allocated I/O messages.
* @nmsgs: Number of allocated I/O messages.
* @msg_count: Number of pending I/O messages in the virtqueue.
+ * @dma_pages: Pages backing DMA messages, retained until messages are freed.
+ * @ndma_pages: Number of retained pages.
+ * @owned_dma_area: Driver-owned PCM buffer backing asynchronous messages.
+ * @owned_dma_bytes: Size of @owned_dma_area.
* @msg_empty: Notify when msg_count is zero.
*/
struct virtio_pcm_substream {
@@ -53,6 +59,7 @@
spinlock_t lock;
size_t buffer_bytes;
size_t hw_ptr;
+ bool capture_rx_seeded;
bool xfer_enabled;
bool xfer_xrun;
bool stopped;
@@ -62,6 +69,12 @@
struct virtio_pcm_msg **msgs;
unsigned int nmsgs;
unsigned int msg_count;
+ struct page **dma_pages;
+ unsigned int ndma_pages;
+#ifndef CONFIG_MMU
+ u8 *owned_dma_area;
+ size_t owned_dma_bytes;
+#endif
wait_queue_head_t msg_empty;
};
diff --git a/sound/virtio/virtio_pcm_msg.c b/sound/virtio/virtio_pcm_msg.c
--- a/sound/virtio/virtio_pcm_msg.c
+++ b/sound/virtio/virtio_pcm_msg.c
@@ -3,6 +3,9 @@
* virtio-snd: Virtio sound device
* Copyright (C) 2021 OpenSynergy GmbH
*/
+#include <linux/limits.h>
+#include <linux/mm.h>
+#include <linux/overflow.h>
#include <sound/pcm_params.h>
#include "virtio_card.h"
@@ -13,6 +16,7 @@
* @xfer: Request header payload.
* @status: Response header payload.
* @length: Data length in bytes.
+ * @data_offset: Offset in the driver-owned PCM buffer on NOMMU systems.
* @sgs: Payload scatter-gather table.
*/
struct virtio_pcm_msg {
@@ -20,6 +24,9 @@
struct virtio_snd_pcm_xfer xfer;
struct virtio_snd_pcm_status status;
size_t length;
+#ifndef CONFIG_MMU
+ size_t data_offset;
+#endif
struct scatterlist sgs[];
};
@@ -37,9 +44,8 @@
};
/**
- * virtsnd_pcm_sg_num() - Count the number of sg-elements required to represent
- * vmalloc'ed buffer.
- * @data: Pointer to vmalloc'ed buffer.
+ * virtsnd_pcm_sg_num() - Count the sg-elements for a page-backed buffer.
+ * @data: Pointer to the page-backed buffer.
* @length: Buffer size.
*
* Context: Any context.
@@ -47,14 +53,18 @@
*/
static int virtsnd_pcm_sg_num(u8 *data, unsigned int length)
{
- phys_addr_t sg_address;
- unsigned int sg_length;
+ phys_addr_t sg_address = 0;
+ unsigned int sg_length = 0;
int num = 0;
while (length) {
struct page *pg = vmalloc_to_page(data);
- phys_addr_t pg_address = page_to_phys(pg);
+ phys_addr_t pg_address;
size_t pg_length;
+
+ if (!pg)
+ return -EINVAL;
+ pg_address = page_to_phys(pg);
pg_length = PAGE_SIZE - offset_in_page(data);
if (pg_length > length)
@@ -75,11 +85,80 @@
return num;
}
-/**
- * virtsnd_pcm_sg_from() - Build sg-list from vmalloc'ed buffer.
+#ifdef CONFIG_MMU
+/**
+ * virtsnd_pcm_dma_pages_put() - Release retained PCM buffer pages.
+ * @vss: VirtIO PCM substream.
+ *
+ * Context: Process context.
+ */
+static void virtsnd_pcm_dma_pages_put(struct virtio_pcm_substream *vss)
+{
+ while (vss->ndma_pages)
+ put_page(vss->dma_pages[--vss->ndma_pages]);
+ kfree(vss->dma_pages);
+ vss->dma_pages = NULL;
+}
+
+/**
+ * virtsnd_pcm_dma_pages_get() - Retain the pages backing the PCM buffer.
+ * @vss: VirtIO PCM substream.
+ * @data: PCM buffer address.
+ * @length: PCM buffer size.
+ *
+ * Keep the backing pages alive while virtqueue descriptors can still refer to
+ * them, even if ALSA releases the vmalloc mapping after a failed drain.
+ *
+ * Context: Process context.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_pcm_dma_pages_get(struct virtio_pcm_substream *vss,
+ u8 *data, size_t length)
+{
+ size_t i;
+ size_t npages;
+ size_t span;
+
+ if (!data || !length || !is_vmalloc_addr(data))
+ return -EINVAL;
+ if (vss->dma_pages || vss->ndma_pages)
+ return -EBUSY;
+
+ if (check_add_overflow(length, (size_t)offset_in_page(data), &span))
+ return -EOVERFLOW;
+
+ npages = span / PAGE_SIZE + !!(span % PAGE_SIZE);
+ if (npages > UINT_MAX)
+ return -EOVERFLOW;
+
+ vss->dma_pages = kcalloc(npages, sizeof(*vss->dma_pages), GFP_KERNEL);
+ if (!vss->dma_pages)
+ return -ENOMEM;
+
+ for (i = 0; i < npages; i++) {
+ struct page *page = vmalloc_to_page(data + i * PAGE_SIZE);
+
+ if (!page)
+ goto err_put_pages;
+
+ get_page(page);
+ vss->dma_pages[vss->ndma_pages++] = page;
+ }
+
+ return 0;
+
+err_put_pages:
+ virtsnd_pcm_dma_pages_put(vss);
+
+ return -EINVAL;
+}
+#endif
+
+/**
+ * virtsnd_pcm_sg_from() - Build an sg-list from a page-backed buffer.
* @sgs: Preallocated sg-list to populate.
* @nsgs: The maximum number of elements in the @sgs.
- * @data: Pointer to vmalloc'ed buffer.
+ * @data: Pointer to the page-backed buffer.
* @length: Buffer size.
*
* Splits the buffer into physically contiguous parts and makes an sg-list of
@@ -132,36 +211,99 @@
int virtsnd_pcm_msg_alloc(struct virtio_pcm_substream *vss,
unsigned int periods, unsigned int period_bytes)
{
- struct snd_pcm_runtime *runtime = vss->substream->runtime;
+ struct snd_pcm_runtime *runtime;
+ size_t buffer_bytes;
unsigned int i;
+ int rc;
+
+ if (vss->msgs || vss->nmsgs || vss->dma_pages || vss->ndma_pages)
+ return -EBUSY;
+#ifndef CONFIG_MMU
+ if (vss->owned_dma_area || vss->owned_dma_bytes)
+ return -EBUSY;
+#endif
+ if (!periods || !period_bytes)
+ return -EINVAL;
+
+ if (check_mul_overflow((size_t)periods, (size_t)period_bytes,
+ &buffer_bytes))
+ return -EOVERFLOW;
+
+ if (!vss->substream || !vss->substream->runtime)
+ return -EINVAL;
+ runtime = vss->substream->runtime;
+ if (!runtime->dma_area || buffer_bytes > runtime->dma_bytes)
+ return -EINVAL;
+
+#ifdef CONFIG_MMU
+ rc = virtsnd_pcm_dma_pages_get(vss, runtime->dma_area, buffer_bytes);
+ if (rc)
+ return rc;
+#else
+ vss->owned_dma_area = kzalloc(buffer_bytes, GFP_KERNEL);
+ if (!vss->owned_dma_area)
+ return -ENOMEM;
+ vss->owned_dma_bytes = buffer_bytes;
+#endif
vss->msgs = kzalloc_objs(*vss->msgs, periods);
- if (!vss->msgs)
- return -ENOMEM;
+ if (!vss->msgs) {
+ rc = -ENOMEM;
+ goto err_free_pages;
+ }
vss->nmsgs = periods;
for (i = 0; i < periods; ++i) {
- u8 *data = runtime->dma_area + period_bytes * i;
- int sg_num = virtsnd_pcm_sg_num(data, period_bytes);
+ int sg_num;
struct virtio_pcm_msg *msg;
+ u8 *data;
+#ifdef CONFIG_MMU
+ data = runtime->dma_area + (size_t)period_bytes * i;
+#else
+ data = vss->owned_dma_area + (size_t)period_bytes * i;
+#endif
+ sg_num = virtsnd_pcm_sg_num(data, period_bytes);
+ if (sg_num < 0) {
+ rc = sg_num;
+ goto err_free_msgs;
+ }
msg = kzalloc_flex(*msg, sgs, sg_num + 2);
- if (!msg)
- return -ENOMEM;
+ if (!msg) {
+ rc = -ENOMEM;
+ goto err_free_msgs;
+ }
msg->substream = vss;
+ vss->msgs[i] = msg;
sg_init_one(&msg->sgs[PCM_MSG_SG_XFER], &msg->xfer,
sizeof(msg->xfer));
sg_init_one(&msg->sgs[PCM_MSG_SG_STATUS], &msg->status,
sizeof(msg->status));
+#ifndef CONFIG_MMU
+ msg->data_offset = (size_t)period_bytes * i;
+#endif
virtsnd_pcm_sg_from(&msg->sgs[PCM_MSG_SG_DATA], sg_num, data,
period_bytes);
-
- vss->msgs[i] = msg;
}
return 0;
+
+err_free_msgs:
+ virtsnd_pcm_msg_free(vss);
+ return rc;
+
+err_free_pages:
+#ifdef CONFIG_MMU
+ virtsnd_pcm_dma_pages_put(vss);
+#else
+ kfree(vss->owned_dma_area);
+ vss->owned_dma_area = NULL;
+ vss->owned_dma_bytes = 0;
+#endif
+
+ return rc;
}
/**
@@ -177,6 +319,13 @@
for (i = 0; vss->msgs && i < vss->nmsgs; ++i)
kfree(vss->msgs[i]);
kfree(vss->msgs);
+#ifdef CONFIG_MMU
+ virtsnd_pcm_dma_pages_put(vss);
+#else
+ kfree(vss->owned_dma_area);
+ vss->owned_dma_area = NULL;
+ vss->owned_dma_bytes = 0;
+#endif
vss->msgs = NULL;
vss->nmsgs = 0;
@@ -199,6 +348,7 @@
guard(spinlock_irqsave)(&vss->lock);
for (i = 0; vss->msgs && i < vss->nmsgs; ++i)
vss->msgs[i]->length = 0;
+ vss->capture_rx_seeded = false;
}
/**
@@ -228,8 +378,15 @@
bool notify = false;
int rc;
+ if (!bytes)
+ return 0;
+ if (!period_bytes || !vss->msgs || offset >= vss->buffer_bytes ||
+ bytes > vss->buffer_bytes - offset)
+ return -EINVAL;
start = offset / period_bytes;
end = (offset + bytes - 1) / period_bytes;
+ if (end >= vss->nmsgs)
+ return -EINVAL;
for (i = start; i <= end; i++) {
struct virtio_pcm_msg *msg = vss->msgs[i];
@@ -248,6 +405,33 @@
if (msg->length == period_bytes) {
msg->xfer.stream_id = cpu_to_le32(vss->sid);
memset(&msg->status, 0, sizeof(msg->status));
+
+#ifndef CONFIG_MMU
+ if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK) {
+ struct snd_pcm_runtime *runtime =
+ vss->substream ? vss->substream->runtime : NULL;
+ size_t data_bytes = msg->length;
+
+ if (!runtime || !runtime->dma_area || !vss->owned_dma_area ||
+ msg->data_offset > runtime->dma_bytes ||
+ data_bytes > runtime->dma_bytes - msg->data_offset ||
+ msg->data_offset > vss->owned_dma_bytes ||
+ data_bytes > vss->owned_dma_bytes - msg->data_offset) {
+ dev_err_ratelimited(&vdev->dev,
+ "SID %u: invalid playback buffer for I/O message\n",
+ vss->sid);
+ msg->length -= n;
+ if (msg_count != vss->msg_count &&
+ !(vss->features &
+ (1U << VIRTIO_SND_PCM_F_MSG_POLLING)) &&
+ virtqueue_kick_prepare(vqueue))
+ virtqueue_notify(vqueue);
+ return -EINVAL;
+ }
+ memcpy(vss->owned_dma_area + msg->data_offset,
+ runtime->dma_area + msg->data_offset, data_bytes);
+ }
+#endif
if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK)
rc = virtqueue_add_sgs(vqueue, psgs, 2, 1, msg,
@@ -363,15 +547,48 @@
* the hw_ptr value is unconditionally advanced.
*/
guard(spinlock)(&vss->lock);
+#ifndef CONFIG_MMU
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ vss->xfer_enabled && written_bytes > sizeof(msg->status)) {
+ struct snd_pcm_runtime *runtime =
+ vss->substream ? vss->substream->runtime : NULL;
+ size_t reported_bytes = written_bytes - sizeof(msg->status);
+ size_t data_bytes = min_t(size_t, reported_bytes, msg->length);
+
+ if (!runtime || !runtime->dma_area || !vss->owned_dma_area ||
+ msg->data_offset > runtime->dma_bytes ||
+ data_bytes > runtime->dma_bytes - msg->data_offset ||
+ msg->data_offset > vss->owned_dma_bytes ||
+ data_bytes > vss->owned_dma_bytes - msg->data_offset)
+ dev_err_ratelimited(&vss->snd->vdev->dev,
+ "SID %u: invalid capture buffer for I/O message\n",
+ vss->sid);
+ else
+ memcpy(runtime->dma_area + msg->data_offset,
+ vss->owned_dma_area + msg->data_offset, data_bytes);
+ }
+#endif
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ written_bytes > sizeof(msg->status) &&
+ written_bytes - sizeof(msg->status) > msg->length)
+ dev_err_ratelimited(&vss->snd->vdev->dev,
+ "SID %u: capture length exceeds I/O message capacity\n",
+ vss->sid);
/*
* If the capture substream returned an incorrect status, then just
- * increase the hw_ptr by the message size.
+ * increase the hw_ptr by the message size. Clamp valid capture lengths to
+ * the actual SG payload capacity before accounting them.
*/
if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK ||
- written_bytes <= sizeof(msg->status))
+ written_bytes <= sizeof(msg->status)) {
vss->hw_ptr += msg->length;
- else
- vss->hw_ptr += written_bytes - sizeof(msg->status);
+ } else {
+ size_t data_bytes = min_t(size_t,
+ written_bytes - sizeof(msg->status),
+ msg->length);
+
+ vss->hw_ptr += data_bytes;
+ }
if (vss->hw_ptr >= vss->buffer_bytes)
vss->hw_ptr -= vss->buffer_bytes;
@@ -387,7 +604,6 @@
runtime->delay =
bytes_to_frames(runtime,
le32_to_cpu(msg->status.latency_bytes));
-
schedule_work(&vss->elapsed_period);
} else if (!vss->msg_count) {
wake_up_all(&vss->msg_empty);
diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
--- a/sound/virtio/virtio_pcm_ops.c
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -25,6 +25,8 @@
* signal or due to a timeout. In this case, the device can still access
* messages even after calling ops->hw_free(). It can also issue an interrupt,
* and the interrupt handler will also try to access message structures.
+ * The messages retain references to the PCM buffer pages until they are
+ * freed, so late DMA does not target pages released by ALSA.
*
* Therefore, freeing of already allocated messages occurs:
*
@@ -228,8 +230,19 @@
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct virtio_device *vdev = vss->snd->vdev;
unsigned int msg_count;
+ size_t period_buffer_bytes;
bool stopped;
int rc;
+
+ /* Fixed descriptors require whole-byte periods covering the buffer. */
+ if (check_mul_overflow((size_t)params_periods(hw_params),
+ (size_t)params_period_bytes(hw_params),
+ &period_buffer_bytes) ||
+ period_buffer_bytes != params_buffer_bytes(hw_params) ||
+ (params_period_size(hw_params) *
+ (u64)snd_pcm_format_physical_width(params_format(hw_params)) *
+ params_channels(hw_params)) % 8)
+ return -EINVAL;
scoped_guard(spinlock_irqsave, &vss->lock) {
msg_count = vss->msg_count;
@@ -380,8 +393,12 @@
substream->runtime->stop_operating = true;
return -EBADFD;
}
- if (vss->direction == SNDRV_PCM_STREAM_CAPTURE)
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ !vss->capture_rx_seeded) {
rc = virtsnd_pcm_msg_send(vss, 0, vss->buffer_bytes);
+ if (!rc)
+ vss->capture_rx_seeded = true;
+ }
if (rc) {
vss->stopped = true;
substream->runtime->stop_operating = true;
^ permalink raw reply [flat|nested] 29+ messages in thread* Re: [PATCH v11 04/14] ALSA: virtio: Keep PCM DMA buffers alive through device ownership
2026-10-31 2:08 ` [PATCH v11 04/14] ALSA: virtio: Keep PCM DMA buffers alive through device ownership Joonho Lee
@ 2026-10-31 2:33 ` sashiko-bot
0 siblings, 0 replies; 29+ messages in thread
From: sashiko-bot @ 2026-10-31 2:33 UTC (permalink / raw)
To: Joonho Lee; +Cc: virtualization, Michael S. Tsirkin, Eugenio Perez
> Retain references to the pages backing ALSA's vmalloc buffer until its
> queued I/O messages are freed. On NOMMU systems, use driver-owned memory
> for DMA and copy playback data before submission and capture data after
> completion, so ALSA buffer release cannot invalidate an active request.
>
> Validate the PCM buffer and each period before building scatterlists.
> Clamp device-reported capture lengths to the message capacity before
> advancing the hardware pointer, preventing an oversized completion from
> accounting bytes beyond the buffer actually submitted.
>
> Require whole-byte periods whose total matches the negotiated buffer.
> Check offset, length and the final message index before indexing the
> message array, including empty transfers and arithmetic wraparound.
>
> Seed the ordinary capture ring once per prepare. Native STOP preserves
> queued requests and unread samples, so PAUSE_RELEASE must retain their
> ownership. Re-enqueuing the entire ring adds another period to pending
> message lengths and exposes unread DMA slots to the device. Return
> consumed space through the existing indirect ACK path.
>
> Fixes: f40a28679e0b ("ALSA: virtio: handling control and I/O messages for the PCM device")
> Assisted-by: LLM
> Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261031020855.2402-1-mynameisjune111@gmail.com?part=4
^ permalink raw reply [flat|nested] 29+ messages in thread
* [PATCH v11 05/14] ALSA: virtio: Keep control payloads alive through DMA completion
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (3 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 04/14] ALSA: virtio: Keep PCM DMA buffers alive through device ownership Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:20 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 06/14] ALSA: virtio: wait through signals for PCM teardown Joonho Lee
` (8 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Control requests can expose caller-owned payloads to the device after a
synchronous send times out. Keep request and response headers and payloads
in the reference-counted message so caller cleanup cannot invalidate DMA.
Keep the queue reference until device completion or post-reset cleanup,
even when the caller times out or is interrupted. Consume the caller's
reference on every send path, and let response readers retain an extra
reference through copyout. Check payload sizes and allocation arithmetic
before building the scatterlists.
A control value payload is also read by the CPU as a typed structure. DMA
cacheline alignment alone does not guarantee the structure's CPU alignment.
Align regions to the greater of the DMA cacheline and control-value type
alignment, and reserve prefix slack from the buffer base so typed accesses
remain aligned while scatterlist regions stay on cacheline boundaries.
Keep response values in a separately allocated aligned response buffer
so INTEGER64 control accesses are aligned from this patch onward.
Fixes: 9d45e514da88 ("ALSA: virtio: handling control messages")
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/virtio/virtio_ctl_msg.c b/sound/virtio/virtio_ctl_msg.c
--- a/sound/virtio/virtio_ctl_msg.c
+++ b/sound/virtio/virtio_ctl_msg.c
@@ -3,7 +3,10 @@
* virtio-snd: Virtio sound device
* Copyright (C) 2021 OpenSynergy GmbH
*/
+#include <linux/dma-mapping.h>
+#include <linux/limits.h>
#include <linux/moduleparam.h>
+#include <linux/overflow.h>
#include <linux/virtio_config.h>
#include "virtio_card.h"
@@ -11,7 +14,12 @@
/**
* struct virtio_snd_msg - Control message.
* @sg_request: Scattergather list containing a device request (header).
+ * @sg_request_data: Scattergather list containing request data.
* @sg_response: Scattergather list containing a device response (status).
+ * @sg_response_data: Scattergather list containing response data.
+ * @dma_buffer: Message-owned storage for all DMA-visible SG regions.
+ * @request_data_size: Size of the request data buffer.
+ * @response_data_size: Size of the response data buffer.
* @list: Pending message list entry.
* @notify: Request completed notification.
* @ref_count: Reference count used to manage a message lifetime.
@@ -19,7 +27,12 @@
*/
struct virtio_snd_msg {
struct scatterlist sg_request;
+ struct scatterlist sg_request_data;
struct scatterlist sg_response;
+ struct scatterlist sg_response_data;
+ void *dma_buffer;
+ size_t request_data_size;
+ size_t response_data_size;
struct list_head list;
struct completion notify;
refcount_t ref_count;
@@ -47,8 +60,10 @@
*/
void virtsnd_ctl_msg_unref(struct virtio_snd_msg *msg)
{
- if (refcount_dec_and_test(&msg->ref_count))
+ if (refcount_dec_and_test(&msg->ref_count)) {
+ kfree(msg->dma_buffer);
kfree(msg);
+ }
}
/**
@@ -71,12 +86,73 @@
void *virtsnd_ctl_msg_response(struct virtio_snd_msg *msg)
{
return sg_virt(&msg->sg_response);
+}
+
+/**
+ * virtsnd_ctl_msg_request_data() - Get the request data buffer.
+ * @msg: Control message.
+ *
+ * Context: Any context.
+ */
+void *virtsnd_ctl_msg_request_data(struct virtio_snd_msg *msg)
+{
+ return msg->request_data_size ? sg_virt(&msg->sg_request_data) : NULL;
+}
+
+/**
+ * virtsnd_ctl_msg_response_data() - Get the response data buffer.
+ * @msg: Control message.
+ *
+ * Context: Any context.
+ */
+void *virtsnd_ctl_msg_response_data(struct virtio_snd_msg *msg)
+{
+ return msg->response_data_size ? sg_virt(&msg->sg_response_data) : NULL;
+}
+
+/**
+ * virtsnd_ctl_msg_sg_init() - Place one DMA region on cacheline boundaries.
+ * @sg: Scattergather entry for the region.
+ * @cursor: Current location in the message-owned DMA buffer.
+ * @size: Region length.
+ * @alignment: Alignment for DMA cachelines and typed CPU accesses.
+ *
+ * Context: Any context during message allocation.
+ * Return: 0 on success, -EOVERFLOW if the address cannot be represented.
+ */
+static int virtsnd_ctl_msg_sg_init(struct scatterlist *sg, u8 **cursor,
+ size_t size, size_t alignment)
+{
+ uintptr_t address = (uintptr_t)*cursor;
+ uintptr_t end;
+ size_t padding;
+
+ padding = address % alignment;
+ if (padding &&
+ check_add_overflow(address, (uintptr_t)(alignment - padding),
+ &address))
+ return -EOVERFLOW;
+
+ if (check_add_overflow(address, (uintptr_t)size, &end))
+ return -EOVERFLOW;
+
+ padding = end % alignment;
+ if (padding &&
+ check_add_overflow(end, (uintptr_t)(alignment - padding), &end))
+ return -EOVERFLOW;
+
+ sg_init_one(sg, (void *)address, (unsigned int)size);
+ *cursor = (u8 *)end;
+
+ return 0;
}
/**
* virtsnd_ctl_msg_alloc() - Allocate and initialize a control message.
* @request_size: Size of request header.
* @response_size: Size of response header.
+ * @request_data_size: Size of request data buffer.
+ * @response_data_size: Size of response data buffer.
* @gfp: Kernel flags for memory allocation.
*
* The message will be automatically freed when the ref_count value is 0.
@@ -85,20 +161,85 @@
* Return: Allocated message on success, NULL on failure.
*/
struct virtio_snd_msg *virtsnd_ctl_msg_alloc(size_t request_size,
- size_t response_size, gfp_t gfp)
+ size_t response_size,
+ size_t request_data_size,
+ size_t response_data_size,
+ gfp_t gfp)
{
struct virtio_snd_msg *msg;
-
- if (!request_size || !response_size)
+ struct scatterlist *sgs[4];
+ size_t sizes[4] = {
+ request_size,
+ response_size,
+ request_data_size,
+ response_data_size,
+ };
+ size_t alignment;
+ size_t dma_buffer_size;
+ size_t aligned_size;
+ size_t padding;
+ u8 *data;
+ unsigned int i;
+ int cache_alignment;
+ int rc;
+
+ if (!request_size || !response_size || request_size > UINT_MAX ||
+ response_size > UINT_MAX || request_data_size > UINT_MAX ||
+ response_data_size > UINT_MAX)
return NULL;
-
- msg = kzalloc(sizeof(*msg) + request_size + response_size, gfp);
+ cache_alignment = dma_get_cache_alignment();
+ if (cache_alignment <= 0)
+ return NULL;
+ /* DMA coherence does not remove the CPU's type alignment requirement. */
+ alignment = max_t(size_t, cache_alignment,
+ __alignof__(struct virtio_snd_ctl_value));
+
+ /* Reserve prefix alignment slack before the first DMA region. */
+ dma_buffer_size = alignment - 1;
+ for (i = 0; i < ARRAY_SIZE(sizes); ++i) {
+ if (!sizes[i])
+ continue;
+
+ padding = sizes[i] % alignment;
+ aligned_size = sizes[i];
+ if (padding &&
+ check_add_overflow(aligned_size, alignment - padding,
+ &aligned_size))
+ return NULL;
+
+ if (check_add_overflow(dma_buffer_size, aligned_size,
+ &dma_buffer_size))
+ return NULL;
+ }
+
+ msg = kzalloc(sizeof(*msg), gfp);
if (!msg)
return NULL;
- sg_init_one(&msg->sg_request, (u8 *)msg + sizeof(*msg), request_size);
- sg_init_one(&msg->sg_response, (u8 *)msg + sizeof(*msg) + request_size,
- response_size);
+ msg->dma_buffer = kzalloc(dma_buffer_size, gfp);
+ if (!msg->dma_buffer) {
+ kfree(msg);
+ return NULL;
+ }
+ data = msg->dma_buffer;
+ sgs[0] = &msg->sg_request;
+ sgs[1] = &msg->sg_response;
+ sgs[2] = &msg->sg_request_data;
+ sgs[3] = &msg->sg_response_data;
+ for (i = 0; i < ARRAY_SIZE(sizes); ++i) {
+ if (!sizes[i])
+ continue;
+
+ rc = virtsnd_ctl_msg_sg_init(sgs[i], &data, sizes[i], alignment);
+ if (rc) {
+ kfree(msg->dma_buffer);
+ kfree(msg);
+ return NULL;
+ }
+ }
+
+ msg->request_data_size = request_data_size;
+ msg->response_data_size = response_data_size;
INIT_LIST_HEAD(&msg->list);
init_completion(&msg->notify);
@@ -112,17 +253,15 @@
* virtsnd_ctl_msg_send() - Send a control message.
* @snd: VirtIO sound device.
* @msg: Control message.
- * @out_sgs: Additional sg-list to attach to the request header (may be NULL).
- * @in_sgs: Additional sg-list to attach to the response header (may be NULL).
* @nowait: Flag indicating whether to wait for completion.
*
* Context: Any context. Takes and releases the control queue spinlock.
* May sleep if @nowait is false.
+ * Consumes the caller's reference on every return path.
* Return: 0 on success, -errno on failure.
*/
int virtsnd_ctl_msg_send(struct virtio_snd *snd, struct virtio_snd_msg *msg,
- struct scatterlist *out_sgs,
- struct scatterlist *in_sgs, bool nowait)
+ bool nowait)
{
struct virtio_device *vdev = snd->vdev;
struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
@@ -133,6 +272,7 @@
unsigned int nins = 0;
struct scatterlist *psgs[4];
bool notify = false;
+ unsigned long flags;
int rc;
virtsnd_ctl_msg_ref(msg);
@@ -142,27 +282,27 @@
response->code = cpu_to_le32(VIRTIO_SND_S_IO_ERR);
psgs[nouts++] = &msg->sg_request;
- if (out_sgs)
- psgs[nouts++] = out_sgs;
+ if (msg->request_data_size)
+ psgs[nouts++] = &msg->sg_request_data;
psgs[nouts + nins++] = &msg->sg_response;
- if (in_sgs)
- psgs[nouts + nins++] = in_sgs;
-
- scoped_guard(spinlock_irqsave, &queue->lock) {
- if (snd->ctl_msgs_blocked)
- rc = -ENODEV;
- else
- rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins,
- msg, GFP_ATOMIC);
- if (!rc) {
- notify = virtqueue_kick_prepare(queue->vqueue);
-
- list_add_tail(&msg->list, &snd->ctl_msgs);
- if (notify)
- virtqueue_notify(queue->vqueue);
- }
- }
+ if (msg->response_data_size)
+ psgs[nouts + nins++] = &msg->sg_response_data;
+
+ spin_lock_irqsave(&queue->lock, flags);
+ if (snd->ctl_msgs_blocked)
+ rc = -ENODEV;
+ else
+ rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins, msg,
+ GFP_ATOMIC);
+ if (!rc) {
+ notify = virtqueue_kick_prepare(queue->vqueue);
+
+ list_add_tail(&msg->list, &snd->ctl_msgs);
+ if (notify)
+ virtqueue_notify(queue->vqueue);
+ }
+ spin_unlock_irqrestore(&queue->lock, flags);
if (rc) {
dev_err(&vdev->dev, "failed to send control message (0x%08x)\n",
@@ -173,46 +313,36 @@
* called, it is necessary to decrement the reference count.
*/
virtsnd_ctl_msg_unref(msg);
-
- goto on_exit;
- }
-
- if (nowait)
- goto on_exit;
-
- rc = wait_for_completion_interruptible_timeout(&msg->notify, js);
- if (rc <= 0) {
+ } else if (!nowait) {
+ rc = wait_for_completion_interruptible_timeout(&msg->notify, js);
if (!rc) {
dev_err(&vdev->dev,
"control message (0x%08x) timeout\n",
le32_to_cpu(request->code));
rc = -ETIMEDOUT;
+ } else if (rc > 0) {
+ if (READ_ONCE(msg->cancelled)) {
+ rc = -ENODEV;
+ } else {
+ switch (le32_to_cpu(response->code)) {
+ case VIRTIO_SND_S_OK:
+ rc = 0;
+ break;
+ case VIRTIO_SND_S_NOT_SUPP:
+ rc = -EOPNOTSUPP;
+ break;
+ case VIRTIO_SND_S_IO_ERR:
+ rc = -EIO;
+ break;
+ default:
+ rc = -EINVAL;
+ break;
+ }
+ }
}
-
- goto on_exit;
- }
-
- if (READ_ONCE(msg->cancelled)) {
- rc = -ENODEV;
- goto on_exit;
- }
-
- switch (le32_to_cpu(response->code)) {
- case VIRTIO_SND_S_OK:
- rc = 0;
- break;
- case VIRTIO_SND_S_NOT_SUPP:
- rc = -EOPNOTSUPP;
- break;
- case VIRTIO_SND_S_IO_ERR:
- rc = -EIO;
- break;
- default:
- rc = -EINVAL;
- break;
- }
-
-on_exit:
+ }
+
+ /* Drop the reference consumed by this send attempt. */
virtsnd_ctl_msg_unref(msg);
return rc;
@@ -308,10 +438,23 @@
{
struct virtio_snd_msg *msg;
struct virtio_snd_query_info *query;
- struct scatterlist sg;
+ size_t info_size;
+ int rc;
+
+ if (count < 0)
+ return -EINVAL;
+
+ if (size > UINT_MAX ||
+ check_mul_overflow((size_t)count, size, &info_size) ||
+ info_size > UINT_MAX)
+ return -EOVERFLOW;
+
+ if (info_size && !info)
+ return -EINVAL;
msg = virtsnd_ctl_msg_alloc(sizeof(*query),
- sizeof(struct virtio_snd_hdr), GFP_KERNEL);
+ sizeof(struct virtio_snd_hdr), 0, info_size,
+ GFP_KERNEL);
if (!msg)
return -ENOMEM;
@@ -321,9 +464,13 @@
query->count = cpu_to_le32(count);
query->size = cpu_to_le32(size);
- sg_init_one(&sg, info, count * size);
-
- return virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
+ virtsnd_ctl_msg_ref(msg);
+ rc = virtsnd_ctl_msg_send(snd, msg, false);
+ if (!rc && info_size)
+ memcpy(info, virtsnd_ctl_msg_response_data(msg), info_size);
+ virtsnd_ctl_msg_unref(msg);
+
+ return rc;
}
/**
diff --git a/sound/virtio/virtio_ctl_msg.h b/sound/virtio/virtio_ctl_msg.h
--- a/sound/virtio/virtio_ctl_msg.h
+++ b/sound/virtio/virtio_ctl_msg.h
@@ -21,20 +21,28 @@
void *virtsnd_ctl_msg_response(struct virtio_snd_msg *msg);
struct virtio_snd_msg *virtsnd_ctl_msg_alloc(size_t request_size,
- size_t response_size, gfp_t gfp);
+ size_t response_size,
+ size_t request_data_size,
+ size_t response_data_size,
+ gfp_t gfp);
+
+void *virtsnd_ctl_msg_request_data(struct virtio_snd_msg *msg);
+
+void *virtsnd_ctl_msg_response_data(struct virtio_snd_msg *msg);
int virtsnd_ctl_msg_send(struct virtio_snd *snd, struct virtio_snd_msg *msg,
- struct scatterlist *out_sgs,
- struct scatterlist *in_sgs, bool nowait);
+ bool nowait);
/**
* virtsnd_ctl_msg_send_sync() - Simplified sending of synchronous message.
* @snd: VirtIO sound device.
* @msg: Control message.
*
- * After returning from this function, the message will be deleted. If message
- * content is still needed, the caller must additionally to
- * virtsnd_ctl_msg_ref/unref() it.
+ * This function consumes the caller's message reference on return. A message
+ * accepted by the control queue keeps its queue reference until completion or
+ * post-reset cleanup, including when this function returns on timeout or
+ * interruption. Callers that read the response after success must retain an
+ * additional reference through that access.
*
* The msg_timeout_ms module parameter defines the message completion timeout.
* If the message is not completed within this time, the function will return an
@@ -49,7 +57,7 @@
static inline int virtsnd_ctl_msg_send_sync(struct virtio_snd *snd,
struct virtio_snd_msg *msg)
{
- return virtsnd_ctl_msg_send(snd, msg, NULL, NULL, false);
+ return virtsnd_ctl_msg_send(snd, msg, false);
}
/**
@@ -63,7 +71,7 @@
static inline int virtsnd_ctl_msg_send_async(struct virtio_snd *snd,
struct virtio_snd_msg *msg)
{
- return virtsnd_ctl_msg_send(snd, msg, NULL, NULL, true);
+ return virtsnd_ctl_msg_send(snd, msg, true);
}
void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd);
diff --git a/sound/virtio/virtio_kctl.c b/sound/virtio/virtio_kctl.c
--- a/sound/virtio/virtio_kctl.c
+++ b/sound/virtio/virtio_kctl.c
@@ -3,8 +3,10 @@
* virtio-snd: Virtio sound device
* Copyright (C) 2022 OpenSynergy GmbH
*/
+#include <linux/limits.h>
+#include <linux/overflow.h>
+#include <linux/virtio_config.h>
#include <sound/control.h>
-#include <linux/virtio_config.h>
#include "virtio_card.h"
@@ -157,14 +159,16 @@
struct virtio_snd_ctl_hdr *hdr;
struct virtio_snd_ctl_value *kvalue;
size_t request_size = sizeof(*hdr);
- size_t response_size = sizeof(struct virtio_snd_hdr) + sizeof(*kvalue);
+ size_t response_size = sizeof(struct virtio_snd_hdr);
unsigned int i;
int rc;
- msg = virtsnd_ctl_msg_alloc(request_size, response_size, GFP_KERNEL);
+ msg = virtsnd_ctl_msg_alloc(request_size, response_size, 0,
+ sizeof(*kvalue), GFP_KERNEL);
if (!msg)
return -ENOMEM;
+ /* Response lifetime through ALSA value copyout. */
virtsnd_ctl_msg_ref(msg);
hdr = virtsnd_ctl_msg_request(msg);
@@ -175,8 +179,7 @@
if (rc)
goto on_failure;
- kvalue = (void *)((u8 *)virtsnd_ctl_msg_response(msg) +
- sizeof(struct virtio_snd_hdr));
+ kvalue = virtsnd_ctl_msg_response_data(msg);
switch (type) {
case VIRTIO_SND_CTL_TYPE_BOOLEAN:
@@ -233,7 +236,8 @@
size_t response_size = sizeof(struct virtio_snd_hdr);
unsigned int i;
- msg = virtsnd_ctl_msg_alloc(request_size, response_size, GFP_KERNEL);
+ msg = virtsnd_ctl_msg_alloc(request_size, response_size, 0, 0,
+ GFP_KERNEL);
if (!msg)
return -ENOMEM;
@@ -288,22 +292,27 @@
struct virtio_snd *snd = snd_kcontrol_chip(kcontrol);
struct virtio_snd_msg *msg;
struct virtio_snd_ctl_hdr *hdr;
- unsigned int *tlv;
- struct scatterlist sg;
+ size_t request_data_size = 0;
+ size_t response_data_size = 0;
int rc;
+ switch (op_flag) {
+ case SNDRV_CTL_TLV_OP_READ:
+ response_data_size = size;
+ break;
+ case SNDRV_CTL_TLV_OP_WRITE:
+ case SNDRV_CTL_TLV_OP_CMD:
+ request_data_size = size;
+ break;
+ default:
+ return -EINVAL;
+ }
+
msg = virtsnd_ctl_msg_alloc(sizeof(*hdr), sizeof(struct virtio_snd_hdr),
+ request_data_size, response_data_size,
GFP_KERNEL);
if (!msg)
return -ENOMEM;
-
- tlv = kzalloc(size, GFP_KERNEL);
- if (!tlv) {
- rc = -ENOMEM;
- goto on_msg_unref;
- }
-
- sg_init_one(&sg, tlv, size);
hdr = virtsnd_ctl_msg_request(msg);
hdr->control_id = cpu_to_le32(kcontrol->private_value);
@@ -312,13 +321,16 @@
case SNDRV_CTL_TLV_OP_READ:
hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_TLV_READ);
- rc = virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
- if (!rc) {
- if (copy_to_user(utlv, tlv, size))
- rc = -EFAULT;
- }
-
- break;
+ /* Response lifetime through user copyout. */
+ virtsnd_ctl_msg_ref(msg);
+ rc = virtsnd_ctl_msg_send(snd, msg, false);
+ if (!rc && size &&
+ copy_to_user(utlv, virtsnd_ctl_msg_response_data(msg),
+ size))
+ rc = -EFAULT;
+ virtsnd_ctl_msg_unref(msg);
+
+ return rc;
case SNDRV_CTL_TLV_OP_WRITE:
case SNDRV_CTL_TLV_OP_CMD:
if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
@@ -327,28 +339,16 @@
hdr->hdr.code =
cpu_to_le32(VIRTIO_SND_R_CTL_TLV_COMMAND);
- if (copy_from_user(tlv, utlv, size)) {
- rc = -EFAULT;
- goto on_msg_unref;
- } else {
- rc = virtsnd_ctl_msg_send(snd, msg, &sg, NULL, false);
+ if (size && copy_from_user(virtsnd_ctl_msg_request_data(msg), utlv,
+ size)) {
+ virtsnd_ctl_msg_unref(msg);
+ return -EFAULT;
}
- break;
- default:
- rc = -EINVAL;
- /* We never get here - we listed all values for op_flag */
- WARN_ON(1);
- goto on_msg_unref;
- }
- kfree(tlv);
- return rc;
-
-on_msg_unref:
- virtsnd_ctl_msg_unref(msg);
- kfree(tlv);
-
- return rc;
+ return virtsnd_ctl_msg_send(snd, msg, false);
+ }
+
+ return -EINVAL;
}
/**
@@ -369,27 +369,36 @@
struct virtio_snd_msg *msg;
struct virtio_snd_ctl_hdr *hdr;
unsigned int n = le32_to_cpu(kinfo->value.enumerated.items);
- struct scatterlist sg;
-
- msg = virtsnd_ctl_msg_alloc(sizeof(*hdr),
- sizeof(struct virtio_snd_hdr), GFP_KERNEL);
- if (!msg)
- return -ENOMEM;
+ size_t items_size;
+ int rc;
+
+ if (check_mul_overflow((size_t)n, sizeof(*kctl->items), &items_size) ||
+ items_size > UINT_MAX)
+ return -EOVERFLOW;
kctl->items = devm_kcalloc(&vdev->dev, n, sizeof(*kctl->items),
GFP_KERNEL);
- if (!kctl->items) {
- virtsnd_ctl_msg_unref(msg);
- return -ENOMEM;
- }
-
- sg_init_one(&sg, kctl->items, n * sizeof(*kctl->items));
+ if (!kctl->items)
+ return -ENOMEM;
+
+ msg = virtsnd_ctl_msg_alloc(sizeof(*hdr),
+ sizeof(struct virtio_snd_hdr), 0, items_size,
+ GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
hdr = virtsnd_ctl_msg_request(msg);
hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_ENUM_ITEMS);
hdr->control_id = cpu_to_le32(cid);
- return virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
+ /* Item-buffer lifetime through the control-list copyout. */
+ virtsnd_ctl_msg_ref(msg);
+ rc = virtsnd_ctl_msg_send(snd, msg, false);
+ if (!rc && items_size)
+ memcpy(kctl->items, virtsnd_ctl_msg_response_data(msg), items_size);
+ virtsnd_ctl_msg_unref(msg);
+
+ return rc;
}
/**
diff --git a/sound/virtio/virtio_pcm_msg.c b/sound/virtio/virtio_pcm_msg.c
--- a/sound/virtio/virtio_pcm_msg.c
+++ b/sound/virtio/virtio_pcm_msg.c
@@ -684,7 +684,7 @@
break;
}
- msg = virtsnd_ctl_msg_alloc(request_size, response_size, gfp);
+ msg = virtsnd_ctl_msg_alloc(request_size, response_size, 0, 0, gfp);
if (msg) {
struct virtio_snd_pcm_hdr *hdr = virtsnd_ctl_msg_request(msg);
^ permalink raw reply [flat|nested] 29+ messages in thread* Re: [PATCH v11 05/14] ALSA: virtio: Keep control payloads alive through DMA completion
2026-10-31 2:08 ` [PATCH v11 05/14] ALSA: virtio: Keep control payloads alive through DMA completion Joonho Lee
@ 2026-10-31 2:20 ` sashiko-bot
0 siblings, 0 replies; 29+ messages in thread
From: sashiko-bot @ 2026-10-31 2:20 UTC (permalink / raw)
To: Joonho Lee; +Cc: virtualization, Michael S. Tsirkin, Eugenio Perez
> Control requests can expose caller-owned payloads to the device after a
> synchronous send times out. Keep request and response headers and payloads
> in the reference-counted message so caller cleanup cannot invalidate DMA.
>
> Keep the queue reference until device completion or post-reset cleanup,
> even when the caller times out or is interrupted. Consume the caller's
> reference on every send path, and let response readers retain an extra
> reference through copyout. Check payload sizes and allocation arithmetic
> before building the scatterlists.
>
> A control value payload is also read by the CPU as a typed structure. DMA
> cacheline alignment alone does not guarantee the structure's CPU alignment.
> Align regions to the greater of the DMA cacheline and control-value type
> alignment, and reserve prefix slack from the buffer base so typed accesses
> remain aligned while scatterlist regions stay on cacheline boundaries.
>
> Keep response values in a separately allocated aligned response buffer
> so INTEGER64 control accesses are aligned from this patch onward.
>
> Fixes: 9d45e514da88 ("ALSA: virtio: handling control messages")
> Assisted-by: LLM
> Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261031020855.2402-1-mynameisjune111@gmail.com?part=5
^ permalink raw reply [flat|nested] 29+ messages in thread
* [PATCH v11 06/14] ALSA: virtio: wait through signals for PCM teardown
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (4 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 05/14] ALSA: virtio: Keep control payloads alive through DMA completion Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:27 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 07/14] ALSA: pcm: mark stop-threshold accesses for capture policy sampling Joonho Lee
` (7 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
A signal can end the interruptible wait while a STOP or RELEASE request is
still pending. A later teardown may then submit another RELEASE before the
first request completes.
Keep both waits non-interruptible and use the existing message timeout.
Other control requests remain interruptible. Device reset still cancels the
pending request and wakes the waiter.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/virtio/virtio_ctl_msg.c b/sound/virtio/virtio_ctl_msg.c
--- a/sound/virtio/virtio_ctl_msg.c
+++ b/sound/virtio/virtio_ctl_msg.c
@@ -314,7 +314,20 @@
*/
virtsnd_ctl_msg_unref(msg);
} else if (!nowait) {
- rc = wait_for_completion_interruptible_timeout(&msg->notify, js);
+ /*
+ * Teardown must observe completion even with a pending signal.
+ * Otherwise a subsequent open can retry RELEASE while the device
+ * is still processing the previous teardown request.
+ */
+ switch (le32_to_cpu(request->code)) {
+ case VIRTIO_SND_R_PCM_STOP:
+ case VIRTIO_SND_R_PCM_RELEASE:
+ rc = wait_for_completion_timeout(&msg->notify, js);
+ break;
+ default:
+ rc = wait_for_completion_interruptible_timeout(&msg->notify, js);
+ break;
+ }
if (!rc) {
dev_err(&vdev->dev,
"control message (0x%08x) timeout\n",
diff --git a/sound/virtio/virtio_ctl_msg.h b/sound/virtio/virtio_ctl_msg.h
--- a/sound/virtio/virtio_ctl_msg.h
+++ b/sound/virtio/virtio_ctl_msg.h
@@ -47,6 +47,9 @@
* The msg_timeout_ms module parameter defines the message completion timeout.
* If the message is not completed within this time, the function will return an
* error.
+ * PCM STOP and RELEASE wait through pending signals within this timeout.
+ * Other requests remain interruptible. Device reset cancels and wakes either
+ * kind of waiter.
*
* Context: Any context that permits to sleep.
* Return: 0 on success, -errno on failure.
^ permalink raw reply [flat|nested] 29+ messages in thread* [PATCH v11 07/14] ALSA: pcm: mark stop-threshold accesses for capture policy sampling
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (5 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 06/14] ALSA: virtio: wait through signals for PCM teardown Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:14 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 08/14] ALSA: pcm: report partial progress under the stream lock Joonho Lee
` (6 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
The staged virtio-snd capture path needs to sample stop_threshold from
completion context to distinguish free-running capture from bounded
capture. Software parameters can update this field while capture runs.
Mark the runtime stop-threshold assignments with WRITE_ONCE and the proc
status read with READ_ONCE. This pairs the assignments with the driver's
READ_ONCE policy sampling in patch 9.
These annotations do not provide a transaction for the entire sw_params
update. The driver serializes its cached policy and accounting with its
own substream lock.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -2958,7 +2958,7 @@
runtime->oss.mmap_bytes);
#endif
/* In mmap mode we never stop */
- runtime->stop_threshold = runtime->boundary;
+ WRITE_ONCE(runtime->stop_threshold, runtime->boundary);
return 0;
}
diff --git a/sound/core/pcm.c b/sound/core/pcm.c
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -422,7 +422,8 @@
snd_iprintf(buffer, "period_step: %u\n", runtime->period_step);
snd_iprintf(buffer, "avail_min: %lu\n", runtime->control->avail_min);
snd_iprintf(buffer, "start_threshold: %lu\n", runtime->start_threshold);
- snd_iprintf(buffer, "stop_threshold: %lu\n", runtime->stop_threshold);
+ snd_iprintf(buffer, "stop_threshold: %lu\n",
+ READ_ONCE(runtime->stop_threshold));
snd_iprintf(buffer, "silence_threshold: %lu\n", runtime->silence_threshold);
snd_iprintf(buffer, "silence_size: %lu\n", runtime->silence_size);
snd_iprintf(buffer, "boundary: %lu\n", runtime->boundary);
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -871,7 +871,7 @@
runtime->period_step = 1;
runtime->control->avail_min = runtime->period_size;
runtime->start_threshold = 1;
- runtime->stop_threshold = runtime->buffer_size;
+ WRITE_ONCE(runtime->stop_threshold, runtime->buffer_size);
runtime->silence_threshold = 0;
runtime->silence_size = 0;
runtime->boundary = runtime->buffer_size;
@@ -1062,7 +1062,8 @@
runtime->period_step = params->period_step;
runtime->control->avail_min = params->avail_min;
runtime->start_threshold = params->start_threshold;
- runtime->stop_threshold = params->stop_threshold;
+ /* Drivers may sample the stop policy from completion context. */
+ WRITE_ONCE(runtime->stop_threshold, params->stop_threshold);
runtime->silence_threshold = params->silence_threshold;
runtime->silence_size = params->silence_size;
params->boundary = runtime->boundary;
^ permalink raw reply [flat|nested] 29+ messages in thread* [PATCH v11 08/14] ALSA: pcm: report partial progress under the stream lock
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (6 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 07/14] ALSA: pcm: mark stop-threshold accesses for capture policy sampling Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:13 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 09/14] ALSA: virtio: add staged capture accounting and lifecycle recovery Joonho Lee
` (5 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Staged capture can make readable data available before a complete period
has elapsed. Skipping notification leaves a blocked reader asleep, while
using the period-interrupt path for this event can infer a false ring wrap
when the notification is delayed.
Add snd_pcm_progress_under_stream_lock() to update the hardware pointer
through the non-interrupt path and notify readers and fasync listeners.
It runs under the caller's PCM stream lock and does not tick the PCM timer.
The driver must release its pointer and trigger locks before calling it.
Existing period notification callers keep their current behavior.
Atomic and nonatomic synthetic PCM tests reproduced the missing wakeup
and false-wrap alternatives. The new helper delivered 64 final frames and
reported four available frames after delayed partial progress without XRUN.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -1182,6 +1182,7 @@
int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream,
unsigned int cmd, void *arg);
void snd_pcm_period_elapsed_under_stream_lock(struct snd_pcm_substream *substream);
+void snd_pcm_progress_under_stream_lock(struct snd_pcm_substream *substream);
void snd_pcm_period_elapsed(struct snd_pcm_substream *substream);
snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
void *buf, bool interleaved,
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1919,6 +1919,25 @@
EXPORT_SYMBOL(snd_pcm_period_elapsed_under_stream_lock);
/**
+ * snd_pcm_progress_under_stream_lock - Report progress without a period IRQ
+ * @substream: PCM substream
+ *
+ * Context: PCM stream lock held, with no driver pointer or trigger locks held.
+ * Updates the pointer and wakes readers for partial-period transfers. Unlike
+ * a period notification, this does not imply an elapsed period or tick the PCM
+ * timer. The same pointer, trigger and timestamp callbacks may be invoked.
+ */
+void snd_pcm_progress_under_stream_lock(struct snd_pcm_substream *substream)
+{
+ if (PCM_RUNTIME_CHECK(substream) || !snd_pcm_running(substream))
+ return;
+ snd_pcm_update_hw_ptr(substream);
+ snd_kill_fasync(substream->runtime->fasync, SIGIO, POLL_IN);
+}
+EXPORT_SYMBOL_GPL(snd_pcm_progress_under_stream_lock);
+
+
+/**
* snd_pcm_period_elapsed() - update the status of runtime for the next period by acquiring lock of
* PCM substream.
* @substream: the instance of PCM substream.
^ permalink raw reply [flat|nested] 29+ messages in thread* Re: [PATCH v11 08/14] ALSA: pcm: report partial progress under the stream lock
2026-10-31 2:08 ` [PATCH v11 08/14] ALSA: pcm: report partial progress under the stream lock Joonho Lee
@ 2026-10-31 2:13 ` sashiko-bot
0 siblings, 0 replies; 29+ messages in thread
From: sashiko-bot @ 2026-10-31 2:13 UTC (permalink / raw)
To: Joonho Lee; +Cc: virtualization, Michael S. Tsirkin, Eugenio Perez
> Staged capture can make readable data available before a complete period
> has elapsed. Skipping notification leaves a blocked reader asleep, while
> using the period-interrupt path for this event can infer a false ring wrap
> when the notification is delayed.
>
> Add snd_pcm_progress_under_stream_lock() to update the hardware pointer
> through the non-interrupt path and notify readers and fasync listeners.
> It runs under the caller's PCM stream lock and does not tick the PCM timer.
> The driver must release its pointer and trigger locks before calling it.
> Existing period notification callers keep their current behavior.
>
> Atomic and nonatomic synthetic PCM tests reproduced the missing wakeup
> and false-wrap alternatives. The new helper delivered 64 final frames and
> reported four available frames after delayed partial progress without XRUN.
>
> Assisted-by: LLM
> Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261031020855.2402-1-mynameisjune111@gmail.com?part=8
^ permalink raw reply [flat|nested] 29+ messages in thread
* [PATCH v11 09/14] ALSA: virtio: add staged capture accounting and lifecycle recovery
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (7 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 08/14] ALSA: pcm: report partial progress under the stream lock Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:51 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 10/14] ALSA: virtio: prioritize staged capture period work Joonho Lee
` (4 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Staged capture needs request-owned DMA storage and separate produced,
observed and consumed positions when shared clients use a boundary stop
threshold. Synchronize that policy with RX completion and acknowledgment.
Keep native running state, RELEASE obligations and reset epochs separate
from ALSA runtime state.
Serialize prepare, sync_stop, hw_params and hw_free with lifecycle_lock.
Bind control requests to their originating epoch. Exclude linked prepare
from playback and capture ACK through each member's buffer_mutex trylock
while retaining the buffer-to-PCM lock order. Check the stream state after
acquiring lifecycle_lock in sync_stop to preserve a newer active stream.
Disable period work until open succeeds and synchronously at close.
Cancel it after hw_free teardown, including error paths.
Preserve ordinary capture's seeded RX ring across native pause. A rejected
STOP can complete RX requests while xfer_enabled is clear. Restore the
queue state and wake readers afterwards. Apply START failure cleanup and
successful wakeups to the already-running recovery path too. Capture
failures retain XRUN and teardown state until prepare recovers them.
Track ordinary capture completions with monotonic counters. If a whole
ring completes between observations, the modulo position becomes
ambiguous. Report XRUN and permit prepare recovery, avoiding indefinite
waits after a rejected pause.
Recovery notifications can run without another completed period. Track
the notification floor and use snd_pcm_progress_under_stream_lock() for
those wakeups. Keep period_elapsed and PCM timer ticks for actual new
periods. Otherwise the pause jiffies reset can make an empty notification
look like a whole-ring advance and expose stale audio after RESET.
Retain capture XRUN across subsequent completions and reject ACK after
the latch is set. Playback retains its existing completion behavior.
Native pause rejection, running-path failure and successful recovery were
exercised on ordinary and staged capture. A raw SYNC_PTR ACK without
HWSYNC reproduced the missing XRUN rejection. Recovery and reopen passed
with KASAN and lockdep. A candidate using period_elapsed for every resume
wake returned an old ring of samples and an extra timer tick; separating
progress notifications restored the expected sample hashes and timer
behavior.
The compatibility options stay disabled by default. RESET conversion
and notification priority follow separately.
Link: https://sashiko.dev/#/patchset/20261030052629.27742-1-mynameisjune111%40gmail.com?part=9
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/virtio/virtio_card.c b/sound/virtio/virtio_card.c
--- a/sound/virtio/virtio_card.c
+++ b/sound/virtio/virtio_card.c
@@ -350,6 +350,22 @@
struct virtio_device *vdev = snd->vdev;
unsigned int i;
+ for (i = 0; snd->substreams && i < snd->nsubstreams; ++i) {
+ struct virtio_pcm_substream *vss = &snd->substreams[i];
+ struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
+
+ guard(spinlock_irqsave)(&queue->lock);
+ guard(spinlock)(&vss->lock);
+ vss->reset_epoch++;
+ vss->resetting = true;
+ vss->prepared = false;
+ vss->device_running = false;
+ vss->release_required = false;
+ vss->control_uncertain = false;
+ vss->capture_reset_observing = false;
+ vss->xfer_enabled = false;
+ vss->suspended = true;
+ }
virtio_reset_device(vdev);
/* Deleting a virtqueue does not unmap its outstanding descriptors. */
@@ -367,8 +383,16 @@
queue->vqueue = NULL;
spin_unlock_irqrestore(&queue->lock, flags);
}
-
vdev->config->del_vqs(vdev);
+ for (i = 0; snd->substreams && i < snd->nsubstreams; ++i) {
+ struct virtio_pcm_substream *vss = &snd->substreams[i];
+
+ cancel_work_sync(&vss->elapsed_period);
+ guard(spinlock_irqsave)(&vss->lock);
+ vss->stopped = false;
+ vss->xfer_xrun = false;
+ vss->pause_restart_state = VIRTSND_PCM_PAUSE_RESTART_NONE;
+ }
}
/**
@@ -441,6 +465,7 @@
{
struct virtio_snd *snd = vdev->priv;
int rc;
+ unsigned int i;
rc = virtsnd_find_vqs(snd);
if (rc)
@@ -449,6 +474,12 @@
virtio_device_ready(vdev);
virtsnd_ctl_msg_enable(snd);
+ for (i = 0; i < snd->nsubstreams; ++i) {
+ struct virtio_pcm_substream *vss = &snd->substreams[i];
+
+ guard(spinlock_irqsave)(&vss->lock);
+ vss->resetting = false;
+ }
virtsnd_enable_event_vq(snd);
return 0;
diff --git a/sound/virtio/virtio_ctl_msg.c b/sound/virtio/virtio_ctl_msg.c
--- a/sound/virtio/virtio_ctl_msg.c
+++ b/sound/virtio/virtio_ctl_msg.c
@@ -23,6 +23,9 @@
* @list: Pending message list entry.
* @notify: Request completed notification.
* @ref_count: Reference count used to manage a message lifetime.
+ * @pcm: Optional PCM generation owner, valid until control queue teardown.
+ * @pcm_epoch: Operation generation captured before request allocation.
+ * @submitted: Request was handed to the device.
* @cancelled: Request canceled during device teardown.
*/
struct virtio_snd_msg {
@@ -37,7 +40,49 @@
struct completion notify;
refcount_t ref_count;
bool cancelled;
+ bool submitted;
+ struct virtio_pcm_substream *pcm;
+ u64 pcm_epoch;
};
+
+/* Bind an operation's original generation before publishing the request. */
+void virtsnd_ctl_msg_bind_pcm(struct virtio_snd_msg *msg,
+ struct virtio_pcm_substream *vss, u64 epoch)
+{
+ msg->pcm = vss;
+ msg->pcm_epoch = epoch;
+}
+
+u64 virtsnd_ctl_msg_pcm_epoch(struct virtio_snd_msg *msg)
+{
+ return msg->pcm_epoch;
+}
+
+static int virtsnd_ctl_msg_enqueue(struct virtio_snd *snd,
+ struct virtio_snd_msg *msg,
+ struct scatterlist **sgs,
+ unsigned int nouts, unsigned int nins)
+{
+ struct virtqueue *vq = virtsnd_control_queue(snd)->vqueue;
+
+ if (!msg->pcm)
+ return virtqueue_add_sgs(vq, sgs, nouts, nins, msg, GFP_ATOMIC);
+
+ /* Control queue -> PCM lock serializes enqueue against device reset. */
+ guard(spinlock)(&msg->pcm->lock);
+ if (msg->pcm->resetting || msg->pcm->reset_epoch != msg->pcm_epoch)
+ return -ECANCELED;
+ return virtqueue_add_sgs(vq, sgs, nouts, nins, msg, GFP_ATOMIC);
+}
+
+/* Caller retains a reference across the synchronous send. */
+bool virtsnd_ctl_msg_uncertain(struct virtio_snd_msg *msg, int rc)
+{
+ return msg->submitted &&
+ (rc == -ETIMEDOUT || rc == -ERESTARTSYS ||
+ READ_ONCE(msg->cancelled));
+}
+
/**
* virtsnd_ctl_msg_ref() - Increment reference counter for the message.
@@ -293,9 +338,9 @@
if (snd->ctl_msgs_blocked)
rc = -ENODEV;
else
- rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins, msg,
- GFP_ATOMIC);
+ rc = virtsnd_ctl_msg_enqueue(snd, msg, psgs, nouts, nins);
if (!rc) {
+ msg->submitted = true;
notify = virtqueue_kick_prepare(queue->vqueue);
list_add_tail(&msg->list, &snd->ctl_msgs);
@@ -315,11 +360,14 @@
virtsnd_ctl_msg_unref(msg);
} else if (!nowait) {
/*
- * Teardown must observe completion even with a pending signal.
- * Otherwise a subsequent open can retry RELEASE while the device
- * is still processing the previous teardown request.
+ * PCM state changes must observe completion with a pending signal.
+ * Otherwise recovery can issue a conflicting command while the
+ * device is still processing the previous transition.
*/
switch (le32_to_cpu(request->code)) {
+ 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:
rc = wait_for_completion_timeout(&msg->notify, js);
diff --git a/sound/virtio/virtio_ctl_msg.h b/sound/virtio/virtio_ctl_msg.h
--- a/sound/virtio/virtio_ctl_msg.h
+++ b/sound/virtio/virtio_ctl_msg.h
@@ -11,6 +11,13 @@
struct virtio_snd;
struct virtio_snd_msg;
+struct virtio_pcm_substream;
+
+void virtsnd_ctl_msg_bind_pcm(struct virtio_snd_msg *msg,
+ struct virtio_pcm_substream *vss, u64 epoch);
+u64 virtsnd_ctl_msg_pcm_epoch(struct virtio_snd_msg *msg);
+
+bool virtsnd_ctl_msg_uncertain(struct virtio_snd_msg *msg, int rc);
void virtsnd_ctl_msg_ref(struct virtio_snd_msg *msg);
@@ -47,7 +54,7 @@
* The msg_timeout_ms module parameter defines the message completion timeout.
* If the message is not completed within this time, the function will return an
* error.
- * PCM STOP and RELEASE wait through pending signals within this timeout.
+ * PCM state-changing requests wait through pending signals within this timeout.
* Other requests remain interruptible. Device reset cancels and wakes either
* kind of waiter.
*
diff --git a/sound/virtio/virtio_pcm.c b/sound/virtio/virtio_pcm.c
--- a/sound/virtio/virtio_pcm.c
+++ b/sound/virtio/virtio_pcm.c
@@ -310,8 +310,119 @@
{
struct virtio_pcm_substream *vss =
container_of(work, struct virtio_pcm_substream, elapsed_period);
-
- snd_pcm_period_elapsed(vss->substream);
+ struct snd_pcm_substream *substream = vss->substream;
+ struct snd_pcm_runtime *runtime;
+ size_t period_bytes;
+ u64 period_floor;
+ u64 snapshot;
+ bool staged_capture;
+ bool paused_xrun = false;
+ bool notify = false;
+ bool partial = false;
+ bool requeue = false;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ staged_capture = vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ vss->capture_staging;
+ }
+
+ /* Serialize the pointer snapshot with ALSA's pointer and ACK callbacks. */
+ guard(pcm_stream_lock_irqsave)(substream);
+ if (!substream->runtime)
+ return;
+ if (!snd_pcm_running(substream)) {
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ runtime = substream->runtime;
+ paused_xrun = runtime &&
+ runtime->state == SNDRV_PCM_STATE_PAUSED &&
+ vss->xfer_xrun;
+ if (paused_xrun)
+ virtsnd_pcm_capture_arm_paused_stop(vss);
+ }
+ if (paused_xrun) {
+ /* Stop paused transfers and wake blocked readers. */
+ snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
+ }
+ return;
+ }
+
+ if (!staged_capture) {
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ guard(spinlock_irqsave)(&vss->lock);
+ period_bytes = snd_pcm_lib_period_bytes(substream);
+ period_floor = period_bytes ?
+ div64_ul(vss->capture_copied_total, period_bytes) : 0;
+ partial = vss->xfer_xrun ||
+ period_floor <= vss->capture_notified_periods;
+ if (!partial)
+ vss->capture_notified_periods = period_floor;
+ }
+ /* Resume recovery can wake readers without a new period IRQ. */
+ if (partial)
+ snd_pcm_progress_under_stream_lock(substream);
+ else
+ snd_pcm_period_elapsed_under_stream_lock(substream);
+ return;
+ }
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ runtime = substream->runtime;
+ if (!vss->runtime_active ||
+ (!vss->xfer_enabled && !vss->xfer_xrun) || !runtime)
+ return;
+
+ period_bytes = snd_pcm_lib_period_bytes(substream);
+ if (vss->xfer_xrun) {
+ notify = true;
+ } else if (!period_bytes || period_bytes >= vss->buffer_bytes ||
+ !virtsnd_pcm_capture_counters_valid(vss) ||
+ vss->capture_notified_periods >
+ div64_ul(vss->capture_copied_total, period_bytes)) {
+ vss->xfer_xrun = true;
+ notify = true;
+ } else {
+ period_floor = div64_ul(vss->capture_copied_total, period_bytes);
+ if (period_floor > vss->capture_notified_periods) {
+ /* Reserve crossed boundaries before the callback. */
+ vss->capture_notified_periods = period_floor;
+ notify = true;
+ } else if (vss->capture_copied_total >
+ vss->capture_pointer_seen_total) {
+ notify = true;
+ partial = true;
+ }
+ }
+
+ if (notify) {
+ snapshot = vss->capture_copied_total;
+ vss->capture_callback_snapshot = snapshot;
+ vss->capture_callback_snapshot_active = true;
+ }
+ }
+
+ if (!notify)
+ return;
+
+ /* Pin the callback position while completions keep updating actual totals. */
+ if (partial)
+ snd_pcm_progress_under_stream_lock(substream);
+ else
+ snd_pcm_period_elapsed_under_stream_lock(substream);
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->capture_callback_snapshot_active = false;
+ vss->capture_callback_snapshot = 0;
+ if (vss->runtime_active && vss->xfer_enabled &&
+ !vss->xfer_xrun && substream->runtime) {
+ period_bytes = snd_pcm_lib_period_bytes(substream);
+ if (period_bytes &&
+ vss->capture_copied_total > vss->capture_pointer_seen_total)
+ requeue = true;
+ }
+ }
+
+ if (requeue)
+ virtsnd_pcm_schedule_period_elapsed(vss);
}
/**
@@ -351,8 +462,10 @@
vss->snd = snd;
vss->sid = i;
INIT_WORK(&vss->elapsed_period, virtsnd_pcm_period_elapsed);
+ disable_work(&vss->elapsed_period);
init_waitqueue_head(&vss->msg_empty);
spin_lock_init(&vss->lock);
+ mutex_init(&vss->lifecycle_lock);
}
info = kzalloc_objs(*info, snd->nsubstreams);
@@ -486,7 +599,7 @@
snd_pcm_set_ops(vpcm->pcm, i, &virtsnd_pcm_ops[i]);
}
- snd_pcm_set_managed_buffer_all(vpcm->pcm,
+ snd_pcm_lib_preallocate_pages_for_all(vpcm->pcm,
SNDRV_DMA_TYPE_VMALLOC, NULL,
0, 0);
}
@@ -517,8 +630,11 @@
break;
case VIRTIO_SND_EVT_PCM_XRUN:
scoped_guard(spinlock, &vss->lock) {
- if (vss->xfer_enabled)
+ if (vss->xfer_enabled) {
vss->xfer_xrun = true;
+ if (vss->capture_staging)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ }
}
break;
}
diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h
--- a/sound/virtio/virtio_pcm.h
+++ b/sound/virtio/virtio_pcm.h
@@ -7,13 +7,32 @@
#define VIRTIO_SND_PCM_H
#include <linux/atomic.h>
+#include <linux/mutex.h>
+#include <linux/math64.h>
#include <linux/virtio_config.h>
+#include <linux/workqueue.h>
#include <sound/pcm.h>
#include <sound/pcm-indirect.h>
struct virtio_pcm;
struct virtio_pcm_msg;
struct page;
+
+enum virtio_pcm_pause_restart_state {
+ VIRTSND_PCM_PAUSE_RESTART_NONE,
+ VIRTSND_PCM_PAUSE_RESTART_CONFIGURED,
+ VIRTSND_PCM_PAUSE_RESTART_SET_PARAMS_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_PREPARE_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_PREPARED,
+ VIRTSND_PCM_PAUSE_RESTART_START_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_RUNNING,
+ VIRTSND_PCM_PAUSE_RESTART_STOP_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_STOPPED,
+ VIRTSND_PCM_PAUSE_RESTART_RELEASE_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_RELEASE_SENT,
+ VIRTSND_PCM_PAUSE_RESTART_RELEASED,
+ VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED,
+};
/**
* struct virtio_pcm_substream - VirtIO PCM substream.
@@ -26,17 +45,40 @@
* @pcm_indirect: Kernel indirect pcm structure.
* @hw: Kernel ALSA substream hardware descriptor.
* @elapsed_period: Kernel work to handle the elapsed period state.
+ * @lifecycle_lock: Serializes prepare with synchronous release, outside trigger.
+ * @resetting: Device queues are unavailable until restore completes.
+ * @reset_epoch: Invalidates control replies from before device reset.
* @lock: Spinlock that protects fields shared by interrupt handlers and
* substream operators, including @stopped.
* @buffer_bytes: Current buffer size in bytes.
* @hw_ptr: Substream hardware pointer value in bytes [0 ... buffer_bytes).
+ * @capture_ready: Managed-mode bytes copied but not yet acknowledged by ALSA;
+ * always zero in free-running mode.
+ * @capture_boundary: ALSA boundary captured for this prepared epoch.
+ * @capture_copied_total: Monotonic bytes copied into the capture ring.
+ * @capture_acked_total: Monotonic bytes acknowledged by the capture client.
+ * @capture_pointer_seen_total: Last capture position sampled by ALSA.
+ * @capture_notified_periods: Highest full-period boundary reserved for notify.
+ * @capture_callback_snapshot: Capture position fixed for the period callback.
+ * @capture_callback_snapshot_active: The callback must use its fixed position.
+ * @runtime_active: ALSA runtime buffer may be accessed by the staged path.
+ * @capture_staging: Capture uses request-owned payload buffers.
* @capture_rx_seeded: Ordinary capture ring was queued since prepare.
+ * @capture_started: Non-empty capture data was received since prepare.
+ * @capture_empty: Consecutive empty startup completions.
+ * @capture_free_running: Cached staged-capture policy, protected by @lock.
* @xfer_enabled: Data transfer state (0 - off, 1 - on).
* @xfer_xrun: Data underflow/overflow state (0 - no xrun, 1 - xrun).
* @stopped: True if the substream is stopped and must be released on the device
* side; protected by @lock.
+ * @prepared: Device PREPARE succeeded; protected by @lock.
+ * @device_running: Native START succeeded without a subsequent successful STOP.
+ * @release_required: Successful PREPARE still needs a successful RELEASE.
+ * @control_uncertain: Native control result requires device reset before reuse.
+ * @capture_reset_observing: Reclaim staged samples during RESET pointer capture.
* @suspended: True if the substream is suspended and must be reconfigured on
* the device side at resume.
+ * @pause_restart_state: Device-side state for opt-in pause compatibility.
* @msgs: Allocated I/O messages.
* @nmsgs: Number of allocated I/O messages.
* @msg_count: Number of pending I/O messages in the virtqueue.
@@ -57,15 +99,36 @@
struct snd_pcm_hardware hw;
struct work_struct elapsed_period;
spinlock_t lock;
+ struct mutex lifecycle_lock;
+ u64 reset_epoch;
+ bool resetting;
size_t buffer_bytes;
size_t hw_ptr;
+ size_t capture_ready;
+ snd_pcm_uframes_t capture_boundary;
+ u64 capture_copied_total;
+ u64 capture_acked_total;
+ u64 capture_pointer_seen_total;
+ u64 capture_notified_periods;
+ u64 capture_callback_snapshot;
+ bool capture_callback_snapshot_active;
+ bool runtime_active;
+ bool capture_staging;
+ bool capture_started;
bool capture_rx_seeded;
+ bool capture_free_running;
+ unsigned int capture_empty;
bool xfer_enabled;
bool xfer_xrun;
bool stopped;
- /* Successful PREPARE still needs RELEASE; protected by lock. */
+ bool prepared;
+ /* Native control state, protected by lock. */
+ bool device_running;
bool release_required;
+ bool control_uncertain;
+ bool capture_reset_observing;
bool suspended;
+ enum virtio_pcm_pause_restart_state pause_restart_state;
struct virtio_pcm_msg **msgs;
unsigned int nmsgs;
unsigned int msg_count;
@@ -78,6 +141,64 @@
wait_queue_head_t msg_empty;
};
+/* Caller holds the PCM stream lock and vss->lock. */
+static inline void
+virtsnd_pcm_capture_arm_paused_stop(struct virtio_pcm_substream *vss)
+{
+ struct snd_pcm_runtime *runtime = vss->substream->runtime;
+
+ lockdep_assert_held(&vss->lock);
+ if (!runtime || runtime->state != SNDRV_PCM_STATE_PAUSED)
+ return;
+
+ /* ALSA skips trigger(STOP) when moving a paused stream to XRUN. */
+ vss->xfer_enabled = false;
+ vss->stopped = true;
+ runtime->stop_operating = true;
+}
+
+/* Keep non-staged PCM notifications on schedule_work()'s normal queue. */
+static inline bool
+virtsnd_pcm_schedule_period_elapsed(struct virtio_pcm_substream *vss)
+{
+ return schedule_work(&vss->elapsed_period);
+}
+
+/*
+ * ALSA may observe a subperiod tail before its period callback. Keep actual
+ * unread occupancy separate from pointer observations and notification state;
+ * free-running streams account occupancy from monotonic totals instead.
+ */
+static inline size_t virtsnd_pcm_ring_offset(u64 total, size_t size)
+{
+ u64 remainder;
+
+ div64_u64_rem(total, size, &remainder);
+ return remainder;
+}
+
+static inline bool
+virtsnd_pcm_capture_counters_valid(const struct virtio_pcm_substream *vss)
+{
+ u64 outstanding;
+
+ if (!vss->buffer_bytes ||
+ vss->capture_copied_total < vss->capture_acked_total ||
+ vss->capture_pointer_seen_total > vss->capture_copied_total ||
+ vss->hw_ptr != virtsnd_pcm_ring_offset(vss->capture_copied_total, vss->buffer_bytes) ||
+ (vss->capture_callback_snapshot_active &&
+ (vss->capture_callback_snapshot < vss->capture_pointer_seen_total ||
+ vss->capture_callback_snapshot > vss->capture_copied_total)))
+ return false;
+
+ if (vss->capture_free_running)
+ return !vss->capture_ready;
+
+ outstanding = vss->capture_copied_total - vss->capture_acked_total;
+ return outstanding == (u64)vss->capture_ready &&
+ vss->capture_ready < vss->buffer_bytes;
+}
+
/**
* struct virtio_pcm_stream - VirtIO PCM stream.
* @substreams: VirtIO substreams belonging to the stream.
@@ -108,6 +229,11 @@
extern const struct snd_pcm_ops virtsnd_pcm_ops[];
+extern bool virtsnd_capture_staging;
+extern bool virtsnd_capture_packed_status;
+extern bool virtsnd_capture_allow_short;
+extern bool virtsnd_capture_allow_empty;
+
int virtsnd_pcm_validate(struct virtio_device *vdev);
int virtsnd_pcm_parse_cfg(struct virtio_snd *snd);
@@ -126,11 +252,16 @@
struct virtio_snd_msg *
virtsnd_pcm_ctl_msg_alloc(struct virtio_pcm_substream *vss,
- unsigned int command, gfp_t gfp);
+ unsigned int command, gfp_t gfp, u64 epoch);
int virtsnd_pcm_msg_alloc(struct virtio_pcm_substream *vss,
unsigned int periods, unsigned int period_bytes);
+int virtsnd_pcm_capture_send(struct virtio_pcm_substream *vss);
+
+int virtsnd_pcm_capture_refresh_mode_locked(struct virtio_pcm_substream *vss,
+ bool *free_running);
+
void virtsnd_pcm_msg_free(struct virtio_pcm_substream *vss);
void virtsnd_pcm_msg_reset(struct virtio_pcm_substream *vss);
diff --git a/sound/virtio/virtio_pcm_msg.c b/sound/virtio/virtio_pcm_msg.c
--- a/sound/virtio/virtio_pcm_msg.c
+++ b/sound/virtio/virtio_pcm_msg.c
@@ -3,9 +3,11 @@
* virtio-snd: Virtio sound device
* Copyright (C) 2021 OpenSynergy GmbH
*/
+#include <linux/compiler.h>
#include <linux/limits.h>
#include <linux/mm.h>
#include <linux/overflow.h>
+#include <linux/vmalloc.h>
#include <sound/pcm_params.h>
#include "virtio_card.h"
@@ -16,14 +18,16 @@
* @xfer: Request header payload.
* @status: Response header payload.
* @length: Data length in bytes.
+ * @data: Request-owned payload for staged capture.
* @data_offset: Offset in the driver-owned PCM buffer on NOMMU systems.
* @sgs: Payload scatter-gather table.
*/
struct virtio_pcm_msg {
struct virtio_pcm_substream *substream;
- struct virtio_snd_pcm_xfer xfer;
- struct virtio_snd_pcm_status status;
+ struct virtio_snd_pcm_xfer *xfer;
+ struct virtio_snd_pcm_status *status;
size_t length;
+ u8 *data;
#ifndef CONFIG_MMU
size_t data_offset;
#endif
@@ -228,6 +232,8 @@
if (check_mul_overflow((size_t)periods, (size_t)period_bytes,
&buffer_bytes))
return -EOVERFLOW;
+ if (vss->capture_staging && periods < 2)
+ return -EINVAL;
if (!vss->substream || !vss->substream->runtime)
return -EINVAL;
@@ -236,14 +242,19 @@
return -EINVAL;
#ifdef CONFIG_MMU
- rc = virtsnd_pcm_dma_pages_get(vss, runtime->dma_area, buffer_bytes);
- if (rc)
- return rc;
+ if (!vss->capture_staging) {
+ rc = virtsnd_pcm_dma_pages_get(vss, runtime->dma_area,
+ buffer_bytes);
+ if (rc)
+ return rc;
+ }
#else
- vss->owned_dma_area = kzalloc(buffer_bytes, GFP_KERNEL);
- if (!vss->owned_dma_area)
- return -ENOMEM;
- vss->owned_dma_bytes = buffer_bytes;
+ if (!vss->capture_staging) {
+ vss->owned_dma_area = kzalloc(buffer_bytes, GFP_KERNEL);
+ if (!vss->owned_dma_area)
+ return -ENOMEM;
+ vss->owned_dma_bytes = buffer_bytes;
+ }
#endif
vss->msgs = kzalloc_objs(*vss->msgs, periods);
@@ -255,32 +266,54 @@
vss->nmsgs = periods;
for (i = 0; i < periods; ++i) {
- int sg_num;
struct virtio_pcm_msg *msg;
u8 *data;
+ int sg_num;
+
+ if (vss->capture_staging) {
+ data = vzalloc(period_bytes);
+ } else {
#ifdef CONFIG_MMU
- data = runtime->dma_area + (size_t)period_bytes * i;
+ data = runtime->dma_area + (size_t)period_bytes * i;
#else
- data = vss->owned_dma_area + (size_t)period_bytes * i;
+ data = vss->owned_dma_area + (size_t)period_bytes * i;
#endif
+ }
+ if (!data) {
+ rc = -ENOMEM;
+ goto err_free_msgs;
+ }
+
sg_num = virtsnd_pcm_sg_num(data, period_bytes);
if (sg_num < 0) {
+ if (vss->capture_staging)
+ vfree(data);
rc = sg_num;
goto err_free_msgs;
}
msg = kzalloc_flex(*msg, sgs, sg_num + 2);
if (!msg) {
+ if (vss->capture_staging)
+ vfree(data);
rc = -ENOMEM;
goto err_free_msgs;
}
msg->substream = vss;
+ msg->data = vss->capture_staging ? data : NULL;
vss->msgs[i] = msg;
- sg_init_one(&msg->sgs[PCM_MSG_SG_XFER], &msg->xfer,
- sizeof(msg->xfer));
- sg_init_one(&msg->sgs[PCM_MSG_SG_STATUS], &msg->status,
- sizeof(msg->status));
+ /* DMA payloads must not share cachelines with CPU-owned fields. */
+ msg->xfer = kzalloc(sizeof(*msg->xfer), GFP_KERNEL);
+ msg->status = kzalloc(sizeof(*msg->status), GFP_KERNEL);
+ if (!msg->xfer || !msg->status) {
+ rc = -ENOMEM;
+ goto err_free_msgs;
+ }
+ sg_init_one(&msg->sgs[PCM_MSG_SG_XFER], msg->xfer,
+ sizeof(*msg->xfer));
+ sg_init_one(&msg->sgs[PCM_MSG_SG_STATUS], msg->status,
+ sizeof(*msg->status));
#ifndef CONFIG_MMU
msg->data_offset = (size_t)period_bytes * i;
#endif
@@ -316,8 +349,14 @@
{
unsigned int i;
- for (i = 0; vss->msgs && i < vss->nmsgs; ++i)
- kfree(vss->msgs[i]);
+ for (i = 0; vss->msgs && i < vss->nmsgs; ++i) {
+ if (vss->msgs[i]) {
+ vfree(vss->msgs[i]->data);
+ kfree(vss->msgs[i]->xfer);
+ kfree(vss->msgs[i]->status);
+ kfree(vss->msgs[i]);
+ }
+ }
kfree(vss->msgs);
#ifdef CONFIG_MMU
virtsnd_pcm_dma_pages_put(vss);
@@ -339,15 +378,26 @@
* substream was stopped are never sent to the device, so their length must be
* cleared before the substream is started again.
*
- * Context: Any context. Takes and releases the VirtIO substream spinlock.
+ * Context: Caller holds the VirtIO substream spinlock.
*/
void virtsnd_pcm_msg_reset(struct virtio_pcm_substream *vss)
{
unsigned int i;
- guard(spinlock_irqsave)(&vss->lock);
+ lockdep_assert_held(&vss->lock);
for (i = 0; vss->msgs && i < vss->nmsgs; ++i)
vss->msgs[i]->length = 0;
+ vss->capture_ready = 0;
+ vss->capture_copied_total = 0;
+ vss->capture_acked_total = 0;
+ vss->capture_pointer_seen_total = 0;
+ vss->capture_notified_periods = 0;
+ vss->capture_callback_snapshot = 0;
+ vss->capture_callback_snapshot_active = false;
+ vss->capture_boundary = 0;
+ vss->capture_free_running = false;
+ vss->capture_empty = 0;
+ vss->capture_started = false;
vss->capture_rx_seeded = false;
}
@@ -378,6 +428,8 @@
bool notify = false;
int rc;
+ if (!vqueue || !vss->prepared || vss->suspended)
+ return -EBADFD;
if (!bytes)
return 0;
if (!period_bytes || !vss->msgs || offset >= vss->buffer_bytes ||
@@ -403,8 +455,8 @@
msg->length += n;
if (msg->length == period_bytes) {
- msg->xfer.stream_id = cpu_to_le32(vss->sid);
- memset(&msg->status, 0, sizeof(msg->status));
+ msg->xfer->stream_id = cpu_to_le32(vss->sid);
+ memset(msg->status, 0, sizeof(*msg->status));
#ifndef CONFIG_MMU
if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK) {
@@ -478,6 +530,290 @@
return 0;
}
+/* Caller holds vss->lock. */
+int virtsnd_pcm_capture_refresh_mode_locked(struct virtio_pcm_substream *vss,
+ bool *free_running)
+{
+ struct snd_pcm_runtime *runtime;
+ snd_pcm_uframes_t stop_threshold;
+ u64 outstanding;
+ bool new_free_running;
+
+ if (!vss->capture_staging || !vss->runtime_active || !vss->substream)
+ return -EBADFD;
+
+ runtime = vss->substream->runtime;
+ if (!runtime || !vss->buffer_bytes || !vss->capture_boundary)
+ return -EBADFD;
+
+ /* Validate the currently committed policy before observing a transition. */
+ if (!virtsnd_pcm_capture_counters_valid(vss))
+ return -EIO;
+
+ stop_threshold = READ_ONCE(runtime->stop_threshold);
+ new_free_running = stop_threshold == vss->capture_boundary;
+ if (new_free_running != vss->capture_free_running) {
+ outstanding = vss->capture_copied_total -
+ vss->capture_acked_total;
+ if (new_free_running) {
+ vss->capture_ready = 0;
+ } else {
+ if (outstanding >= vss->buffer_bytes)
+ return -EPIPE;
+ vss->capture_ready = outstanding;
+ }
+ vss->capture_free_running = new_free_running;
+ }
+
+ *free_running = new_free_running;
+ return 0;
+}
+
+/* Caller holds the RX queue and vss locks and has sampled the policy. */
+static int virtsnd_pcm_capture_enqueue(struct virtio_pcm_substream *vss,
+ bool free_running)
+{
+ struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
+ struct virtqueue *vqueue = queue->vqueue;
+ unsigned long period_bytes;
+ size_t free_bytes;
+ size_t request_limit = vss->nmsgs;
+ unsigned int i;
+ bool added = false;
+
+ if (!vqueue || !vss->prepared || vss->suspended ||
+ !vss->capture_staging || !vss->runtime_active)
+ return -EBADFD;
+
+ period_bytes = snd_pcm_lib_period_bytes(vss->substream);
+ if (!period_bytes || !vss->buffer_bytes ||
+ period_bytes >= vss->buffer_bytes ||
+ free_running != vss->capture_free_running ||
+ !virtsnd_pcm_capture_counters_valid(vss) ||
+ vss->msg_count > vss->nmsgs)
+ return -EIO;
+
+ if (!free_running) {
+ free_bytes = vss->buffer_bytes - vss->capture_ready;
+ request_limit = free_bytes / period_bytes +
+ !!(free_bytes % period_bytes);
+ request_limit = min_t(size_t, request_limit, vss->nmsgs);
+ }
+
+ for (i = 0; i < vss->nmsgs && vss->msg_count < request_limit; ++i) {
+ struct virtio_pcm_msg *msg = vss->msgs[i];
+ struct scatterlist *sgs[] = {
+ &msg->sgs[PCM_MSG_SG_XFER],
+ &msg->sgs[PCM_MSG_SG_DATA],
+ &msg->sgs[PCM_MSG_SG_STATUS]
+ };
+ int rc;
+
+ if (msg->length)
+ continue;
+
+ msg->xfer->stream_id = cpu_to_le32(vss->sid);
+ /* Do not let an absent packed trailer reuse old PCM bytes. */
+ memset(msg->data, 0, period_bytes);
+ memset(msg->status, 0, sizeof(*msg->status));
+ msg->status->status = cpu_to_le32(VIRTIO_SND_S_BAD_MSG);
+ rc = virtqueue_add_sgs(vqueue, sgs, 1, 2, msg, GFP_ATOMIC);
+ if (rc) {
+ if (added && !(vss->features &
+ (1U << VIRTIO_SND_PCM_F_MSG_POLLING)) &&
+ virtqueue_kick_prepare(vqueue))
+ virtqueue_notify(vqueue);
+ return rc;
+ }
+
+ msg->length = period_bytes;
+ vss->msg_count++;
+ added = true;
+ }
+
+ if (added && !(vss->features &
+ (1U << VIRTIO_SND_PCM_F_MSG_POLLING)) &&
+ virtqueue_kick_prepare(vqueue))
+ virtqueue_notify(vqueue);
+
+ return 0;
+}
+
+/**
+ * virtsnd_pcm_capture_send() - Refresh policy and queue staged requests.
+ * @vss: VirtIO PCM substream.
+ *
+ * Context: Expects the RX queue and substream spinlocks to be held by caller.
+ * Return: 0 on success, -errno on failure.
+ */
+int virtsnd_pcm_capture_send(struct virtio_pcm_substream *vss)
+{
+ bool free_running;
+ int rc;
+
+ rc = virtsnd_pcm_capture_refresh_mode_locked(vss, &free_running);
+ if (rc)
+ return rc;
+
+ return virtsnd_pcm_capture_enqueue(vss, free_running);
+}
+
+static int virtsnd_pcm_capture_status(const struct virtio_pcm_msg *msg,
+ size_t written_bytes,
+ size_t frame_bytes,
+ size_t *audio_bytes,
+ u32 *latency_bytes)
+{
+ struct virtio_snd_pcm_status status;
+ size_t max_written;
+ size_t first;
+
+ if (!frame_bytes ||
+ check_add_overflow(msg->length, sizeof(status), &max_written) ||
+ written_bytes < sizeof(status) || written_bytes > max_written)
+ return -EIO;
+
+ *audio_bytes = written_bytes - sizeof(status);
+ if (*audio_bytes > msg->length || *audio_bytes % frame_bytes)
+ return -EIO;
+
+ if (virtsnd_capture_packed_status) {
+ first = min_t(size_t, sizeof(status),
+ msg->length - *audio_bytes);
+ if (first)
+ memcpy(&status, msg->data + *audio_bytes, first);
+ if (first < sizeof(status))
+ memcpy((u8 *)&status + first, msg->status,
+ sizeof(status) - first);
+ } else {
+ status = *msg->status;
+ }
+
+ if (le32_to_cpu(status.status) != VIRTIO_SND_S_OK)
+ return -EIO;
+
+ *latency_bytes = le32_to_cpu(status.latency_bytes);
+ return 0;
+}
+
+static void virtsnd_pcm_capture_xrun_locked(struct virtio_pcm_substream *vss)
+{
+ if (!vss->xfer_xrun) {
+ vss->xfer_xrun = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ }
+}
+
+static void virtsnd_pcm_capture_complete(struct virtio_pcm_msg *msg,
+ size_t written_bytes)
+{
+ struct virtio_pcm_substream *vss = msg->substream;
+ size_t audio_bytes = 0;
+ size_t next_ready = 0;
+ u64 next_copied_total = 0;
+ bool free_running = false;
+ bool got_audio = false;
+
+ guard(spinlock)(&vss->lock);
+ vss->msg_count--;
+ if (vss->runtime_active && vss->xfer_enabled && !vss->xfer_xrun) {
+ struct snd_pcm_runtime *runtime = vss->substream->runtime;
+ size_t frame_bytes = runtime ? frames_to_bytes(runtime, 1) : 0;
+ u32 latency_bytes;
+ const char *invalid_reason = NULL;
+
+ /* A full ring is modulo-ambiguous, so fail closed before copying. */
+ if (!runtime || !runtime->dma_area)
+ invalid_reason = "runtime";
+ else if (virtsnd_pcm_capture_refresh_mode_locked(vss,
+ &free_running))
+ invalid_reason = "policy";
+ else if (!virtsnd_pcm_capture_counters_valid(vss))
+ invalid_reason = "counters";
+ else if (vss->hw_ptr !=
+ virtsnd_pcm_ring_offset(vss->capture_copied_total, vss->buffer_bytes))
+ invalid_reason = "hw_ptr";
+ else if (virtsnd_pcm_capture_status(msg, written_bytes,
+ frame_bytes, &audio_bytes,
+ &latency_bytes))
+ invalid_reason = "status";
+ else if (check_add_overflow(vss->capture_copied_total,
+ (u64)audio_bytes,
+ &next_copied_total))
+ invalid_reason = "total_overflow";
+ else if (free_running && audio_bytes >= vss->buffer_bytes)
+ invalid_reason = "payload_exceeds_ring";
+ else if (!free_running &&
+ audio_bytes >= vss->buffer_bytes - vss->capture_ready)
+ invalid_reason = "ring_capacity";
+ else if (!free_running &&
+ check_add_overflow(vss->capture_ready, audio_bytes,
+ &next_ready))
+ invalid_reason = "ready_overflow";
+ else if (!free_running && next_ready >= vss->buffer_bytes)
+ invalid_reason = "ring_full";
+ else if (free_running &&
+ (next_copied_total < vss->capture_pointer_seen_total ||
+ next_copied_total - vss->capture_pointer_seen_total >=
+ vss->buffer_bytes))
+ invalid_reason = "pointer_window";
+ else if (free_running)
+ next_ready = 0;
+
+ if (invalid_reason) {
+ virtsnd_pcm_capture_xrun_locked(vss);
+ dev_warn_ratelimited(&vss->snd->vdev->dev,
+ "SID %u: staged capture completion rejected (%s)\n",
+ vss->sid, invalid_reason);
+ } else if (!audio_bytes) {
+ unsigned int limit = min_t(unsigned int, vss->nmsgs,
+ UINT_MAX / 2) * 2;
+
+ if (!virtsnd_capture_allow_empty || vss->capture_started ||
+ vss->capture_empty >= limit) {
+ virtsnd_pcm_capture_xrun_locked(vss);
+ } else {
+ vss->capture_empty++;
+ }
+ } else if (audio_bytes < msg->length &&
+ !virtsnd_capture_allow_short) {
+ virtsnd_pcm_capture_xrun_locked(vss);
+ } else {
+ size_t ring_ptr = virtsnd_pcm_ring_offset(vss->capture_copied_total,
+ vss->buffer_bytes);
+ size_t first = min(audio_bytes,
+ vss->buffer_bytes - ring_ptr);
+
+ memcpy(runtime->dma_area + ring_ptr, msg->data, first);
+ if (audio_bytes > first)
+ memcpy(runtime->dma_area, msg->data + first,
+ audio_bytes - first);
+ vss->capture_copied_total = next_copied_total;
+ vss->hw_ptr = virtsnd_pcm_ring_offset(next_copied_total, vss->buffer_bytes);
+ vss->capture_ready = next_ready;
+ vss->capture_started = true;
+ vss->capture_empty = 0;
+ runtime->delay = bytes_to_frames(runtime, latency_bytes);
+ got_audio = true;
+ }
+ }
+
+ msg->length = 0;
+ if (vss->runtime_active && vss->xfer_enabled) {
+ if (!vss->xfer_xrun &&
+ virtsnd_pcm_capture_enqueue(vss, free_running)) {
+ dev_warn_ratelimited(&vss->snd->vdev->dev,
+ "SID %u: failed to refill capture queue\n",
+ vss->sid);
+ virtsnd_pcm_capture_xrun_locked(vss);
+ }
+ if (got_audio && !vss->xfer_xrun)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ } else if (!vss->msg_count) {
+ wake_up_all(&vss->msg_empty);
+ }
+}
+
/**
* virtsnd_pcm_msg_pending_num() - Returns the number of pending I/O messages.
* @vss: VirtIO substream.
@@ -529,9 +865,9 @@
* allowed, then each completed message is immediately placed back at the end
* of the queue.
*
- * For the playback substream, @written_bytes is equal to sizeof(msg->status).
- *
- * For the capture substream, @written_bytes is equal to sizeof(msg->status)
+ * For the playback substream, @written_bytes is equal to sizeof(*msg->status).
+ *
+ * For the capture substream, @written_bytes is equal to sizeof(*msg->status)
* plus the number of captured bytes.
*
* Context: Interrupt context. Takes and releases the VirtIO substream spinlock.
@@ -540,6 +876,13 @@
size_t written_bytes)
{
struct virtio_pcm_substream *vss = msg->substream;
+ size_t completed_bytes;
+
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ vss->capture_staging) {
+ virtsnd_pcm_capture_complete(msg, written_bytes);
+ return;
+ }
/*
* hw_ptr always indicates the buffer position of the first I/O message
@@ -549,10 +892,11 @@
guard(spinlock)(&vss->lock);
#ifndef CONFIG_MMU
if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
- vss->xfer_enabled && written_bytes > sizeof(msg->status)) {
+ vss->prepared && !vss->stopped &&
+ written_bytes > sizeof(*msg->status)) {
struct snd_pcm_runtime *runtime =
vss->substream ? vss->substream->runtime : NULL;
- size_t reported_bytes = written_bytes - sizeof(msg->status);
+ size_t reported_bytes = written_bytes - sizeof(*msg->status);
size_t data_bytes = min_t(size_t, reported_bytes, msg->length);
if (!runtime || !runtime->dma_area || !vss->owned_dma_area ||
@@ -569,8 +913,8 @@
}
#endif
if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
- written_bytes > sizeof(msg->status) &&
- written_bytes - sizeof(msg->status) > msg->length)
+ written_bytes > sizeof(*msg->status) &&
+ written_bytes - sizeof(*msg->status) > msg->length)
dev_err_ratelimited(&vss->snd->vdev->dev,
"SID %u: capture length exceeds I/O message capacity\n",
vss->sid);
@@ -580,14 +924,22 @@
* the actual SG payload capacity before accounting them.
*/
if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK ||
- written_bytes <= sizeof(msg->status)) {
- vss->hw_ptr += msg->length;
- } else {
- size_t data_bytes = min_t(size_t,
- written_bytes - sizeof(msg->status),
- msg->length);
-
- vss->hw_ptr += data_bytes;
+ written_bytes <= sizeof(*msg->status))
+ completed_bytes = msg->length;
+ else
+ completed_bytes = min_t(size_t,
+ written_bytes - sizeof(*msg->status),
+ msg->length);
+ vss->hw_ptr += completed_bytes;
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ /* A full unseen ring cannot be represented by the modulo pointer. */
+ if (check_add_overflow(vss->capture_copied_total,
+ (u64)completed_bytes,
+ &vss->capture_copied_total) ||
+ vss->capture_copied_total < vss->capture_pointer_seen_total ||
+ vss->capture_copied_total - vss->capture_pointer_seen_total >=
+ vss->buffer_bytes)
+ vss->xfer_xrun = true;
}
if (vss->hw_ptr >= vss->buffer_bytes)
@@ -595,7 +947,9 @@
msg->length = 0;
- vss->xfer_xrun = false;
+ /* Preserve a latched capture error until prepare recovers it. */
+ if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK)
+ vss->xfer_xrun = false;
vss->msg_count--;
if (vss->xfer_enabled) {
@@ -603,8 +957,8 @@
runtime->delay =
bytes_to_frames(runtime,
- le32_to_cpu(msg->status.latency_bytes));
- schedule_work(&vss->elapsed_period);
+ le32_to_cpu(msg->status->latency_bytes));
+ virtsnd_pcm_schedule_period_elapsed(vss);
} else if (!vss->msg_count) {
wake_up_all(&vss->msg_empty);
}
@@ -664,6 +1018,7 @@
* virtsnd_pcm_ctl_msg_alloc() - Allocate and initialize the PCM device control
* message for the specified substream.
* @vss: VirtIO PCM substream.
+ * @epoch: Operation generation captured before allocation.
* @command: Control request code (VIRTIO_SND_R_PCM_XXX).
* @gfp: Kernel flags for memory allocation.
*
@@ -672,7 +1027,7 @@
*/
struct virtio_snd_msg *
virtsnd_pcm_ctl_msg_alloc(struct virtio_pcm_substream *vss,
- unsigned int command, gfp_t gfp)
+ unsigned int command, gfp_t gfp, u64 epoch)
{
size_t request_size = sizeof(struct virtio_snd_pcm_hdr);
size_t response_size = sizeof(struct virtio_snd_hdr);
@@ -690,6 +1045,7 @@
hdr->hdr.code = cpu_to_le32(command);
hdr->stream_id = cpu_to_le32(vss->sid);
+ virtsnd_ctl_msg_bind_pcm(msg, vss, epoch);
}
return msg;
diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
--- a/sound/virtio/virtio_pcm_ops.c
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -3,9 +3,41 @@
* virtio-snd: Virtio sound device
* Copyright (C) 2021 OpenSynergy GmbH
*/
+#include <linux/moduleparam.h>
+#include <linux/overflow.h>
#include <sound/pcm_params.h>
#include "virtio_card.h"
+
+
+bool virtsnd_capture_staging;
+module_param_named(capture_staging, virtsnd_capture_staging, bool, 0444);
+MODULE_PARM_DESC(capture_staging,
+ "Use request-owned buffers for experimental PCM capture");
+
+bool virtsnd_capture_packed_status;
+module_param_named(capture_packed_status, virtsnd_capture_packed_status,
+ bool, 0444);
+MODULE_PARM_DESC(capture_packed_status,
+ "Read staged capture status after the actual audio payload");
+
+bool virtsnd_capture_allow_short;
+module_param_named(capture_allow_short, virtsnd_capture_allow_short,
+ bool, 0444);
+MODULE_PARM_DESC(capture_allow_short,
+ "Accept non-empty short staged capture responses");
+
+bool virtsnd_capture_allow_empty;
+module_param_named(capture_allow_empty, virtsnd_capture_allow_empty,
+ bool, 0444);
+MODULE_PARM_DESC(capture_allow_empty,
+ "Retry bounded empty startup capture responses");
+
+static bool virtsnd_capture_pause_restart;
+module_param_named(capture_pause_restart, virtsnd_capture_pause_restart,
+ bool, 0444);
+MODULE_PARM_DESC(capture_pause_restart,
+ "Release and reprepare staged capture streams across pause");
/*
* I/O messages lifetime
@@ -97,14 +129,242 @@
};
static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream);
-
-static void virtsnd_pcm_start_failed(struct virtio_pcm_substream *vss)
-{
- scoped_guard(spinlock_irqsave, &vss->lock) {
+static int virtsnd_pcm_sync_stop_locked(struct snd_pcm_substream *substream);
+static int virtsnd_pcm_pause_restart_sync_stop(struct snd_pcm_substream *substream);
+
+static void virtsnd_pcm_start_failed(struct virtio_pcm_substream *vss, u64 epoch)
+{
+ bool notify;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return;
+ vss->xfer_enabled = false;
+ vss->stopped = vss->release_required || vss->msg_count;
+ notify = vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ (!vss->capture_staging || vss->runtime_active);
+ if (notify)
+ vss->xfer_xrun = true;
+ }
+ vss->substream->runtime->stop_operating = true;
+ if (notify)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+}
+
+static bool
+virtsnd_pcm_pause_restart_enabled(struct virtio_pcm_substream *vss)
+{
+ return virtsnd_capture_pause_restart && vss->capture_staging &&
+ vss->direction == SNDRV_PCM_STREAM_CAPTURE;
+}
+
+static bool virtsnd_pcm_pause_restart_transitioning(enum virtio_pcm_pause_restart_state state)
+{
+ switch (state) {
+ case VIRTSND_PCM_PAUSE_RESTART_SET_PARAMS_SUBMITTED:
+ case VIRTSND_PCM_PAUSE_RESTART_PREPARE_SUBMITTED:
+ case VIRTSND_PCM_PAUSE_RESTART_START_SUBMITTED:
+ case VIRTSND_PCM_PAUSE_RESTART_STOP_SUBMITTED:
+ case VIRTSND_PCM_PAUSE_RESTART_RELEASE_SUBMITTED:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static int virtsnd_pcm_send_sync(struct virtio_pcm_substream *vss,
+ struct virtio_snd_msg *msg)
+{
+ u64 epoch = virtsnd_ctl_msg_pcm_epoch(msg);
+ bool uncertain;
+ int rc;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch ||
+ vss->control_uncertain) {
+ rc = vss->control_uncertain ? -EIO : -ECANCELED;
+ virtsnd_ctl_msg_unref(msg);
+ return rc;
+ }
+ }
+ virtsnd_ctl_msg_ref(msg);
+ rc = virtsnd_ctl_msg_send_sync(vss->snd, msg);
+ uncertain = virtsnd_ctl_msg_uncertain(msg, rc);
+ virtsnd_ctl_msg_unref(msg);
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (epoch != vss->reset_epoch || vss->resetting)
+ return -ECANCELED;
+ if (rc && uncertain)
+ vss->control_uncertain = true;
+ }
+ return rc;
+}
+
+static int
+virtsnd_pcm_pause_restart_send(struct virtio_pcm_substream *vss,
+ struct virtio_snd_msg *msg,
+ unsigned long allowed_states,
+ enum virtio_pcm_pause_restart_state submitted_state,
+ enum virtio_pcm_pause_restart_state success_state)
+{
+ enum virtio_pcm_pause_restart_state state;
+ bool uncertain;
+ u64 epoch = virtsnd_ctl_msg_pcm_epoch(msg);
+ int rc;
+
+ if (!virtsnd_pcm_pause_restart_enabled(vss))
+ return virtsnd_pcm_send_sync(vss, msg);
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ state = vss->pause_restart_state;
+ if (vss->resetting || vss->reset_epoch != epoch) {
+ rc = -ECANCELED;
+ } else if (state == VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED) {
+ rc = -EIO;
+ } else if (virtsnd_pcm_pause_restart_transitioning(state)) {
+ vss->pause_restart_state =
+ VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED;
+ rc = -EIO;
+ } else if (!(allowed_states & BIT(state))) {
+ rc = -EBADFD;
+ } else {
+ vss->pause_restart_state = submitted_state;
+ rc = 0;
+ }
+ }
+
+ if (rc) {
+ virtsnd_ctl_msg_unref(msg);
+ return rc;
+ }
+
+ virtsnd_ctl_msg_ref(msg);
+ rc = virtsnd_ctl_msg_send_sync(vss->snd, msg);
+ uncertain = virtsnd_ctl_msg_uncertain(msg, rc);
+ virtsnd_ctl_msg_unref(msg);
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->reset_epoch != epoch || vss->resetting)
+ return -ECANCELED;
+ if ((rc && uncertain) || vss->pause_restart_state != submitted_state) {
+ vss->pause_restart_state =
+ VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED;
+ if (!rc)
+ rc = -EIO;
+ } else if (rc) {
+ vss->pause_restart_state = state;
+ } else {
+ vss->pause_restart_state = success_state;
+ }
+ }
+
+ if (rc && uncertain)
+ dev_err(&vss->snd->vdev->dev,
+ "SID %u: PCM control state is unknown; device reprobe required\n",
+ vss->sid);
+
+ return rc;
+}
+
+static void
+virtsnd_pcm_pause_restart_fail(struct virtio_pcm_substream *vss,
+ bool reset_required, u64 epoch)
+{
+ bool notify_xrun;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return;
+ notify_xrun = vss->runtime_active;
vss->xfer_enabled = false;
vss->stopped = true;
- }
+ vss->xfer_xrun = true;
+ if (reset_required)
+ vss->pause_restart_state =
+ VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED;
+ }
+ if (notify_xrun)
+ virtsnd_pcm_schedule_period_elapsed(vss);
vss->substream->runtime->stop_operating = true;
+}
+
+static int virtsnd_pcm_dev_prepare(struct virtio_pcm_substream *vss, u64 epoch)
+{
+ struct virtio_snd_msg *msg;
+
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_PREPARE,
+ GFP_KERNEL, epoch);
+ if (!msg)
+ return -ENOMEM;
+
+ return virtsnd_pcm_pause_restart_send(vss, msg,
+ BIT(VIRTSND_PCM_PAUSE_RESTART_CONFIGURED) |
+ BIT(VIRTSND_PCM_PAUSE_RESTART_RELEASED) |
+ BIT(VIRTSND_PCM_PAUSE_RESTART_STOPPED) |
+ BIT(VIRTSND_PCM_PAUSE_RESTART_PREPARED),
+ VIRTSND_PCM_PAUSE_RESTART_PREPARE_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_PREPARED);
+}
+
+static int virtsnd_pcm_pause_prepare(struct virtio_pcm_substream *vss, u64 epoch)
+{
+ struct virtio_snd_msg *msg;
+
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_PREPARE,
+ GFP_KERNEL, epoch);
+ if (!msg)
+ return -ENOMEM;
+
+ return virtsnd_pcm_pause_restart_send(vss, msg,
+ BIT(VIRTSND_PCM_PAUSE_RESTART_RELEASED),
+ VIRTSND_PCM_PAUSE_RESTART_PREPARE_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_PREPARED);
+}
+
+static int virtsnd_pcm_release_wait(struct virtio_pcm_substream *vss, u64 epoch)
+{
+ unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
+ long waited;
+
+ waited = wait_event_timeout(vss->msg_empty,
+ !virtsnd_pcm_msg_pending_num(vss), js);
+ guard(spinlock_irqsave)(&vss->lock);
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ if (!waited || vss->msg_count ||
+ vss->pause_restart_state != VIRTSND_PCM_PAUSE_RESTART_RELEASE_SENT)
+ return -ETIMEDOUT;
+ vss->prepared = false;
+ vss->pause_restart_state = VIRTSND_PCM_PAUSE_RESTART_RELEASED;
+ return 0;
+}
+
+static int
+virtsnd_pcm_pause_release_flush(struct virtio_pcm_substream *vss,
+ unsigned long allowed_states, u64 epoch)
+{
+ struct virtio_snd_msg *msg;
+ int rc;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ }
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_RELEASE,
+ GFP_KERNEL, epoch);
+ if (!msg)
+ return -ENOMEM;
+ rc = virtsnd_pcm_pause_restart_send(vss, msg, allowed_states,
+ VIRTSND_PCM_PAUSE_RESTART_RELEASE_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_RELEASE_SENT);
+ if (rc)
+ return rc;
+ return virtsnd_pcm_release_wait(vss, epoch);
+}
+
+static void virtsnd_pcm_pause_restart_failed(struct virtio_pcm_substream *vss,
+ u64 epoch)
+{
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
}
/**
@@ -119,23 +379,35 @@
struct virtio_pcm *vpcm = snd_pcm_substream_chip(substream);
struct virtio_pcm_stream *vs = &vpcm->streams[substream->stream];
struct virtio_pcm_substream *vss = vs->substreams[substream->number];
+ int rc;
substream->runtime->hw = vss->hw;
substream->private_data = vss;
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->capture_staging = virtsnd_capture_staging &&
+ vss->direction == SNDRV_PCM_STREAM_CAPTURE;
+ if (vss->capture_staging) {
+ vss->runtime_active = false;
+ vss->xfer_enabled = false;
+ }
+ }
+
snd_pcm_hw_constraint_integer(substream->runtime,
SNDRV_PCM_HW_PARAM_PERIODS);
scoped_guard(spinlock_irqsave, &vss->lock)
vss->stopped |= !!vss->msg_count;
- vss->suspended = false;
/*
* If the substream has already been used, then the I/O queue may be in
* an invalid state. Just in case, we do a check and try to return the
* queue to its original state, if necessary.
*/
- return virtsnd_pcm_sync_stop(substream);
+ rc = virtsnd_pcm_sync_stop(substream);
+ if (!rc)
+ enable_work(&vss->elapsed_period);
+ return rc;
}
/**
@@ -147,6 +419,15 @@
*/
static int virtsnd_pcm_close(struct snd_pcm_substream *substream)
{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->runtime_active = false;
+ vss->xfer_enabled = false;
+ }
+ /* Block late producers as well as drain already queued notifications. */
+ disable_work_sync(&vss->elapsed_period);
+
return 0;
}
@@ -159,6 +440,7 @@
* @channels: Selected number of channels.
* @format: Selected sample format (SNDRV_PCM_FORMAT_XXX).
* @rate: Selected frame rate.
+ * @epoch: Operation generation captured before preparing the request.
*
* Context: Any context that permits to sleep.
* Return: 0 on success, -errno on failure.
@@ -168,7 +450,7 @@
unsigned int period_bytes,
unsigned int channels,
snd_pcm_format_t format,
- unsigned int rate)
+ unsigned int rate, u64 epoch)
{
struct virtio_snd_msg *msg;
struct virtio_snd_pcm_set_params *request;
@@ -194,7 +476,7 @@
return -EINVAL;
msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_SET_PARAMS,
- GFP_KERNEL);
+ GFP_KERNEL, epoch);
if (!msg)
return -ENOMEM;
@@ -213,7 +495,14 @@
request->features |=
cpu_to_le32(1U << VIRTIO_SND_PCM_F_EVT_XRUNS);
- return virtsnd_ctl_msg_send_sync(vss->snd, msg);
+ return virtsnd_pcm_pause_restart_send(vss, msg,
+ BIT(VIRTSND_PCM_PAUSE_RESTART_NONE) |
+ BIT(VIRTSND_PCM_PAUSE_RESTART_CONFIGURED) |
+ BIT(VIRTSND_PCM_PAUSE_RESTART_PREPARED) |
+ BIT(VIRTSND_PCM_PAUSE_RESTART_STOPPED) |
+ BIT(VIRTSND_PCM_PAUSE_RESTART_RELEASED),
+ VIRTSND_PCM_PAUSE_RESTART_SET_PARAMS_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_CONFIGURED);
}
/**
@@ -232,8 +521,10 @@
unsigned int msg_count;
size_t period_buffer_bytes;
bool stopped;
+ u64 epoch;
int rc;
+ guard(mutex)(&vss->lifecycle_lock);
/* Fixed descriptors require whole-byte periods covering the buffer. */
if (check_mul_overflow((size_t)params_periods(hw_params),
(size_t)params_period_bytes(hw_params),
@@ -243,6 +534,25 @@
(u64)snd_pcm_format_physical_width(params_format(hw_params)) *
params_channels(hw_params)) % 8)
return -EINVAL;
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ epoch = vss->reset_epoch;
+ /* Drain the previous buffer before ALSA can replace its mapping. */
+ rc = virtsnd_pcm_sync_stop_locked(substream);
+ if (rc)
+ return rc;
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->prepared = false;
+ }
+
+ if (vss->capture_staging) {
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->runtime_active = false;
+ vss->xfer_enabled = false;
+ }
+ cancel_work_sync(&vss->elapsed_period);
+ }
scoped_guard(spinlock_irqsave, &vss->lock) {
msg_count = vss->msg_count;
@@ -260,11 +570,16 @@
return -EBADFD;
}
+ rc = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params));
+ if (rc < 0)
+ return rc;
+ substream->runtime->buffer_changed = rc > 0;
+
rc = virtsnd_pcm_dev_set_params(vss, params_buffer_bytes(hw_params),
params_period_bytes(hw_params),
params_channels(hw_params),
params_format(hw_params),
- params_rate(hw_params));
+ params_rate(hw_params), epoch);
if (rc)
return rc;
@@ -274,8 +589,14 @@
*/
virtsnd_pcm_msg_free(vss);
- return virtsnd_pcm_msg_alloc(vss, params_periods(hw_params),
- params_period_bytes(hw_params));
+ rc = virtsnd_pcm_msg_alloc(vss, params_periods(hw_params),
+ params_period_bytes(hw_params));
+ if (!rc && vss->capture_staging) {
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ vss->runtime_active = true;
+ }
+
+ return rc;
}
/**
@@ -288,28 +609,93 @@
static int virtsnd_pcm_hw_free(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ int rc;
+
+ guard(mutex)(&vss->lifecycle_lock);
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->stopped |= vss->prepared;
+ vss->prepared = false;
+ vss->runtime_active = false;
+ vss->xfer_enabled = false;
+ }
+ rc = virtsnd_pcm_sync_stop_locked(substream);
+ cancel_work_sync(&vss->elapsed_period);
+
+ if (vss->capture_staging) {
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->runtime_active = false;
+ vss->xfer_enabled = false;
+ }
+ cancel_work_sync(&vss->elapsed_period);
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->hw_ptr = 0;
+ vss->capture_ready = 0;
+ vss->capture_copied_total = 0;
+ vss->capture_acked_total = 0;
+ vss->capture_pointer_seen_total = 0;
+ vss->capture_notified_periods = 0;
+ vss->capture_callback_snapshot = 0;
+ vss->capture_callback_snapshot_active = false;
+ vss->capture_boundary = 0;
+ vss->capture_free_running = false;
+ }
+ }
/* If the queue is flushed, we can safely free the messages here. */
if (!virtsnd_pcm_msg_pending_num(vss))
virtsnd_pcm_msg_free(vss);
- return 0;
+ snd_pcm_lib_free_pages(substream);
+ return rc;
}
/**
- * virtsnd_pcm_prepare() - Prepare the PCM substream.
+ * virtsnd_pcm_prepare_locked() - Prepare the PCM substream.
* @substream: Kernel ALSA substream.
*
* Context: Process context.
* Return: 0 on success, -errno on failure.
*/
-static int virtsnd_pcm_prepare(struct snd_pcm_substream *substream)
+static int virtsnd_pcm_prepare_locked(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct virtio_device *vdev = vss->snd->vdev;
- struct virtio_snd_msg *msg;
+ bool pause_restart = virtsnd_pcm_pause_restart_enabled(vss);
+ bool free_running;
+ int rc;
bool stopped;
- int rc;
+ bool suspended;
+ u64 epoch;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting)
+ return -ECANCELED;
+ epoch = vss->reset_epoch;
+ stopped = vss->stopped || vss->release_required || vss->msg_count;
+ }
+ if (stopped) {
+ rc = virtsnd_pcm_sync_stop_locked(substream);
+ if (rc)
+ return rc;
+ }
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->prepared = false;
+ suspended = vss->suspended;
+ }
+
+ if (pause_restart) {
+ enum virtio_pcm_pause_restart_state state;
+
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ state = vss->pause_restart_state;
+ if (state == VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED ||
+ virtsnd_pcm_pause_restart_transitioning(state)) {
+ virtsnd_pcm_pause_restart_fail(vss, true, epoch);
+ return -EIO;
+ }
+ }
scoped_guard(spinlock_irqsave, &vss->lock)
stopped = vss->stopped;
@@ -320,47 +706,383 @@
return -EBADFD;
}
- if (!vss->suspended) {
+ if (!suspended) {
if (virtsnd_pcm_msg_pending_num(vss)) {
dev_err(&vdev->dev, "SID %u: invalid I/O queue state\n",
vss->sid);
return -EBADFD;
}
- vss->buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
- vss->hw_ptr = 0;
} else {
struct snd_pcm_runtime *runtime = substream->runtime;
unsigned int buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
unsigned int period_bytes = snd_pcm_lib_period_bytes(substream);
- int rc;
rc = virtsnd_pcm_dev_set_params(vss, buffer_bytes, period_bytes,
runtime->channels,
- runtime->format, runtime->rate);
- if (rc)
+ runtime->format, runtime->rate, epoch);
+ if (rc) {
+ if (pause_restart && rc != -ECANCELED)
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
return rc;
- }
-
- vss->xfer_xrun = false;
- vss->suspended = false;
- vss->msg_count = 0;
- virtsnd_pcm_msg_reset(vss);
-
- memset(&vss->pcm_indirect, 0, sizeof(vss->pcm_indirect));
- vss->pcm_indirect.sw_buffer_size =
- vss->pcm_indirect.hw_buffer_size =
- snd_pcm_lib_buffer_bytes(substream);
-
- msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_PREPARE,
- GFP_KERNEL);
+ }
+ }
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (epoch != vss->reset_epoch || vss->resetting)
+ return -ECANCELED;
+ vss->prepared = false;
+ vss->buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
+ vss->hw_ptr = 0;
+ if (!pause_restart)
+ vss->xfer_xrun = false;
+ vss->suspended = false;
+ vss->msg_count = 0;
+ virtsnd_pcm_msg_reset(vss);
+ memset(&vss->pcm_indirect, 0, sizeof(vss->pcm_indirect));
+ vss->pcm_indirect.sw_buffer_size = vss->buffer_bytes;
+ vss->pcm_indirect.hw_buffer_size = vss->buffer_bytes;
+ if (vss->capture_staging) {
+ vss->capture_boundary = substream->runtime->boundary;
+ rc = virtsnd_pcm_capture_refresh_mode_locked(vss,
+ &free_running);
+ if (rc)
+ return rc;
+ }
+ }
+
+ rc = virtsnd_pcm_dev_prepare(vss, epoch);
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (epoch != vss->reset_epoch || vss->resetting)
+ return -ECANCELED;
+ vss->prepared = !rc;
+ if (!rc)
+ vss->release_required = true;
+ }
+ if (pause_restart) {
+ if (rc) {
+ if (rc == -ECANCELED)
+ return rc;
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
+ } else {
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->stopped = false;
+ vss->xfer_xrun = false;
+ }
+ }
+ }
+
+ return rc;
+}
+
+static int virtsnd_pcm_prepare(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+
+ guard(mutex)(&vss->lifecycle_lock);
+ return virtsnd_pcm_prepare_locked(substream);
+}
+
+static int virtsnd_pcm_pause_restart_start(struct virtio_pcm_substream *vss,
+ bool resume)
+{
+ struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
+ struct virtio_snd_msg *msg;
+ enum virtio_pcm_pause_restart_state state;
+ bool reset_required;
+ bool invalid_state;
+ int rc = 0;
+ u64 epoch;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting)
+ return -ECANCELED;
+ epoch = vss->reset_epoch;
+ state = vss->pause_restart_state;
+ reset_required =
+ state == VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED ||
+ virtsnd_pcm_pause_restart_transitioning(state);
+ invalid_state =
+ vss->xfer_xrun ||
+ (resume &&
+ (state != VIRTSND_PCM_PAUSE_RESTART_RELEASED ||
+ !vss->stopped || vss->msg_count ||
+ !vss->runtime_active)) ||
+ (!resume &&
+ (state != VIRTSND_PCM_PAUSE_RESTART_PREPARED ||
+ vss->stopped));
+ }
+ if (reset_required) {
+ virtsnd_pcm_pause_restart_fail(vss, true, epoch);
+ return -EIO;
+ }
+ if (invalid_state) {
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
+ return -EBADFD;
+ }
+
+ if (resume) {
+ rc = virtsnd_pcm_pause_prepare(vss, epoch);
+ if (rc) {
+ if (rc == -ECANCELED)
+ return rc;
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return rc;
+ }
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch) {
+ rc = -ECANCELED;
+ } else if (vss->pause_restart_state !=
+ VIRTSND_PCM_PAUSE_RESTART_PREPARED ||
+ vss->msg_count || !vss->runtime_active) {
+ rc = -EBADFD;
+ } else {
+ /* Preserve ring accounting, restarting only startup grace. */
+ vss->prepared = true;
+ vss->capture_started = false;
+ vss->capture_empty = 0;
+ }
+ }
+ if (rc) {
+ if (rc == -ECANCELED)
+ return rc;
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return rc;
+ }
+ }
+
+ scoped_guard(spinlock_irqsave, &queue->lock) {
+ guard(spinlock)(&vss->lock);
+ if (vss->resetting || vss->reset_epoch != epoch) {
+ rc = -ECANCELED;
+ } else if (vss->pause_restart_state !=
+ VIRTSND_PCM_PAUSE_RESTART_PREPARED ||
+ vss->msg_count || !vss->runtime_active || vss->xfer_xrun) {
+ rc = -EBADFD;
+ } else {
+ rc = virtsnd_pcm_capture_send(vss);
+ if (!rc)
+ vss->xfer_enabled = true;
+ }
+ }
+ if (rc) {
+ if (rc == -ECANCELED)
+ return rc;
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return rc;
+ }
+
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_START, GFP_KERNEL, epoch);
+ if (!msg) {
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return -ENOMEM;
+ }
+
+ rc = virtsnd_pcm_pause_restart_send(vss, msg,
+ BIT(VIRTSND_PCM_PAUSE_RESTART_PREPARED),
+ VIRTSND_PCM_PAUSE_RESTART_START_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_RUNNING);
+ if (rc) {
+ if (rc == -ECANCELED)
+ return rc;
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return rc;
+ }
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->stopped = false;
+ }
+ virtsnd_pcm_schedule_period_elapsed(vss);
+
+ return 0;
+}
+
+static int virtsnd_pcm_pause_restart_pause(struct virtio_pcm_substream *vss)
+{
+ struct virtio_snd_msg *msg;
+ enum virtio_pcm_pause_restart_state state;
+ int rc;
+ u64 epoch;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting)
+ return -ECANCELED;
+ epoch = vss->reset_epoch;
+ state = vss->pause_restart_state;
+ if (state == VIRTSND_PCM_PAUSE_RESTART_RELEASED) {
+ if (vss->xfer_xrun)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return vss->xfer_xrun ? -EPIPE : 0;
+ }
+ vss->xfer_enabled = false;
+ vss->stopped = true;
+ }
+
+ if (state == VIRTSND_PCM_PAUSE_RESTART_RELEASE_SENT) {
+ /* Trigger holds the PCM lock; this helper never cancels work. */
+ rc = virtsnd_pcm_release_wait(vss, epoch);
+ if (!rc) {
+ guard(spinlock_irqsave)(&vss->lock);
+ rc = vss->xfer_xrun ? -EPIPE : 0;
+ }
+ if (rc && rc != -ECANCELED)
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return rc;
+ }
+
+ if (state == VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED ||
+ virtsnd_pcm_pause_restart_transitioning(state)) {
+ virtsnd_pcm_pause_restart_fail(vss, true, epoch);
+ return -EIO;
+ }
+
+ if (state == VIRTSND_PCM_PAUSE_RESTART_RUNNING) {
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_STOP,
+ GFP_KERNEL, epoch);
+ if (!msg) {
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return -ENOMEM;
+ }
+
+ rc = virtsnd_pcm_pause_restart_send(vss, msg,
+ BIT(VIRTSND_PCM_PAUSE_RESTART_RUNNING),
+ VIRTSND_PCM_PAUSE_RESTART_STOP_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_STOPPED);
+ if (rc) {
+ if (rc == -ECANCELED)
+ return rc;
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return rc;
+ }
+ state = VIRTSND_PCM_PAUSE_RESTART_STOPPED;
+ } else if (state != VIRTSND_PCM_PAUSE_RESTART_STOPPED &&
+ state != VIRTSND_PCM_PAUSE_RESTART_PREPARED) {
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return -EBADFD;
+ }
+
+ rc = virtsnd_pcm_pause_release_flush(vss,
+ BIT(VIRTSND_PCM_PAUSE_RESTART_STOPPED) |
+ BIT(VIRTSND_PCM_PAUSE_RESTART_PREPARED), epoch);
+ if (rc) {
+ if (rc == -ECANCELED)
+ return rc;
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return rc;
+ }
+
+ return 0;
+}
+
+static int virtsnd_pcm_pause_restart_stop(struct virtio_pcm_substream *vss,
+ bool suspend)
+{
+ struct virtio_snd_msg *msg;
+ enum virtio_pcm_pause_restart_state state;
+ int rc;
+ u64 epoch;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting)
+ return -ECANCELED;
+ epoch = vss->reset_epoch;
+ if (!vss->prepared && !vss->msg_count)
+ return 0;
+ if (suspend)
+ vss->suspended = true;
+ vss->xfer_enabled = false;
+ vss->stopped = true;
+ state = vss->pause_restart_state;
+ }
+
+ if (state == VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED ||
+ virtsnd_pcm_pause_restart_transitioning(state)) {
+ virtsnd_pcm_pause_restart_fail(vss, true, epoch);
+ return -EIO;
+ }
+ if (state != VIRTSND_PCM_PAUSE_RESTART_RUNNING)
+ return 0;
+
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_STOP, GFP_KERNEL, epoch);
+ if (!msg) {
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return -ENOMEM;
+ }
+
+ rc = virtsnd_pcm_pause_restart_send(vss, msg,
+ BIT(VIRTSND_PCM_PAUSE_RESTART_RUNNING),
+ VIRTSND_PCM_PAUSE_RESTART_STOP_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_STOPPED);
+ if (rc && rc != -ECANCELED)
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+
+ return rc;
+}
+
+static int virtsnd_pcm_stop_device(struct virtio_pcm_substream *vss, u64 epoch)
+{
+ struct virtio_snd_msg *msg;
+ int rc;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ if (vss->control_uncertain)
+ return -EIO;
+ if (!vss->device_running)
+ return 0;
+ }
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_STOP,
+ GFP_KERNEL, epoch);
if (!msg)
return -ENOMEM;
-
- rc = virtsnd_ctl_msg_send_sync(vss->snd, msg);
+ rc = virtsnd_pcm_send_sync(vss, msg);
+ if (rc)
+ return rc;
+ guard(spinlock_irqsave)(&vss->lock);
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->device_running = false;
+ return 0;
+}
+
+static int virtsnd_pcm_start_queue(struct virtio_pcm_substream *vss, u64 epoch)
+{
+ struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
+ int rc = 0;
+
+ guard(spinlock_irqsave)(&queue->lock);
+ guard(spinlock)(&vss->lock);
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ if (vss->stopped || !vss->prepared || vss->xfer_xrun)
+ return vss->xfer_xrun ? -EPIPE : -EBADFD;
+ if (vss->control_uncertain)
+ return -EIO;
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ if (vss->capture_staging) {
+ rc = vss->runtime_active ? virtsnd_pcm_capture_send(vss) : -EBADFD;
+ } else if (!vss->capture_rx_seeded) {
+ rc = virtsnd_pcm_msg_send(vss, 0, vss->buffer_bytes);
+ if (!rc)
+ vss->capture_rx_seeded = true;
+ }
+ }
if (!rc) {
- guard(spinlock_irqsave)(&vss->lock);
- vss->release_required = true;
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ !vss->capture_staging) {
+ size_t period = snd_pcm_lib_period_bytes(vss->substream);
+
+ /* A synthetic resume notification is not a new period IRQ. */
+ vss->capture_notified_periods = period ?
+ div64_ul(vss->capture_copied_total, period) : 0;
+ }
+ vss->xfer_enabled = true;
}
return rc;
}
@@ -377,72 +1099,226 @@
static int virtsnd_pcm_trigger(struct snd_pcm_substream *substream, int command)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
- struct virtio_snd *snd = vss->snd;
- struct virtio_snd_queue *queue;
struct virtio_snd_msg *msg;
int rc = 0;
+ bool running;
+ u64 epoch;
+
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ epoch = vss->reset_epoch;
+
+ if (virtsnd_pcm_pause_restart_enabled(vss)) {
+ switch (command) {
+ case SNDRV_PCM_TRIGGER_START:
+ return virtsnd_pcm_pause_restart_start(vss, false);
+ case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+ return virtsnd_pcm_pause_restart_start(vss, true);
+ case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+ return virtsnd_pcm_pause_restart_pause(vss);
+ case SNDRV_PCM_TRIGGER_STOP:
+ return virtsnd_pcm_pause_restart_stop(vss, false);
+ case SNDRV_PCM_TRIGGER_SUSPEND:
+ return virtsnd_pcm_pause_restart_stop(vss, true);
+ default:
+ return -EINVAL;
+ }
+ }
switch (command) {
case SNDRV_PCM_TRIGGER_START:
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
- queue = virtsnd_pcm_queue(vss);
-
- scoped_guard(spinlock_irqsave, &queue->lock) {
- guard(spinlock)(&vss->lock);
- if (vss->stopped) {
- substream->runtime->stop_operating = true;
- return -EBADFD;
- }
- if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
- !vss->capture_rx_seeded) {
- rc = virtsnd_pcm_msg_send(vss, 0, vss->buffer_bytes);
- if (!rc)
- vss->capture_rx_seeded = true;
- }
- if (rc) {
- vss->stopped = true;
- substream->runtime->stop_operating = true;
- return rc;
- }
- vss->xfer_enabled = true;
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ running = vss->device_running;
+ /* Preserve queued requests and unread RX data across native pause. */
+ rc = virtsnd_pcm_start_queue(vss, epoch);
+ if (rc) {
+ virtsnd_pcm_start_failed(vss, epoch);
+ return rc;
+ }
+
+ if (running) {
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return 0;
}
msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_START,
- GFP_KERNEL);
+ GFP_KERNEL, epoch);
if (!msg) {
- virtsnd_pcm_start_failed(vss);
+ virtsnd_pcm_start_failed(vss, epoch);
return -ENOMEM;
}
- rc = virtsnd_ctl_msg_send_sync(snd, msg);
- if (rc)
- virtsnd_pcm_start_failed(vss);
-
+ rc = virtsnd_pcm_send_sync(vss, msg);
+ if (rc && rc != -ECANCELED)
+ virtsnd_pcm_start_failed(vss, epoch);
+
+ if (!rc) {
+ guard(spinlock_irqsave)(&vss->lock);
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->device_running = true;
+ }
+ if (!rc && vss->direction == SNDRV_PCM_STREAM_CAPTURE)
+ virtsnd_pcm_schedule_period_elapsed(vss);
return rc;
case SNDRV_PCM_TRIGGER_SUSPEND:
- vss->suspended = true;
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ vss->suspended = true;
fallthrough;
case SNDRV_PCM_TRIGGER_STOP:
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (!vss->prepared)
+ return 0;
if (command != SNDRV_PCM_TRIGGER_PAUSE_PUSH)
vss->stopped = true;
vss->xfer_enabled = false;
- }
-
- msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_STOP,
- GFP_KERNEL);
- if (!msg)
- return -ENOMEM;
-
- return virtsnd_ctl_msg_send_sync(snd, msg);
+ if (!vss->device_running)
+ return 0;
+ }
+
+ rc = virtsnd_pcm_stop_device(vss, epoch);
+ if (rc && command == SNDRV_PCM_TRIGGER_PAUSE_PUSH) {
+ if (virtsnd_pcm_start_queue(vss, epoch)) {
+ guard(spinlock_irqsave)(&vss->lock);
+ if (vss->reset_epoch == epoch && !vss->resetting) {
+ vss->xfer_xrun = true;
+ vss->stopped = true;
+ substream->runtime->stop_operating = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ }
+ } else if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ }
+ }
+ return rc;
default:
return -EINVAL;
}
+
+}
+
+static int
+virtsnd_pcm_pause_restart_sync_stop(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
+ enum virtio_pcm_pause_restart_state state;
+ struct virtio_snd_msg *msg;
+ long waited;
+ int rc;
+ u64 epoch;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting)
+ return -ECANCELED;
+ epoch = vss->reset_epoch;
+ vss->xfer_enabled = false;
+ vss->stopped = true;
+ state = vss->pause_restart_state;
+ }
+ cancel_work_sync(&vss->elapsed_period);
+
+ if (state == VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED ||
+ virtsnd_pcm_pause_restart_transitioning(state)) {
+ virtsnd_pcm_pause_restart_fail(vss, true, epoch);
+ dev_err(&vss->snd->vdev->dev,
+ "SID %u: PCM state is unknown; device reprobe required\n",
+ vss->sid);
+ return -EIO;
+ }
+
+ if (state == VIRTSND_PCM_PAUSE_RESTART_NONE ||
+ state == VIRTSND_PCM_PAUSE_RESTART_CONFIGURED) {
+ if (virtsnd_pcm_msg_pending_num(vss)) {
+ virtsnd_pcm_pause_restart_fail(vss, true, epoch);
+ return -EIO;
+ }
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->stopped = false;
+ }
+ return 0;
+ }
+
+ if (state == VIRTSND_PCM_PAUSE_RESTART_RUNNING) {
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_STOP,
+ GFP_KERNEL, epoch);
+ if (!msg) {
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
+ return -ENOMEM;
+ }
+
+ rc = virtsnd_pcm_pause_restart_send(vss, msg,
+ BIT(VIRTSND_PCM_PAUSE_RESTART_RUNNING),
+ VIRTSND_PCM_PAUSE_RESTART_STOP_SUBMITTED,
+ VIRTSND_PCM_PAUSE_RESTART_STOPPED);
+ if (rc) {
+ if (rc == -ECANCELED)
+ return rc;
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
+ return rc;
+ }
+ state = VIRTSND_PCM_PAUSE_RESTART_STOPPED;
+ }
+
+ if (state == VIRTSND_PCM_PAUSE_RESTART_RELEASE_SENT ||
+ state == VIRTSND_PCM_PAUSE_RESTART_RELEASED) {
+ waited = wait_event_timeout(vss->msg_empty,
+ !virtsnd_pcm_msg_pending_num(vss), js);
+ if (waited <= 0) {
+ rc = waited ? (int)waited : -ETIMEDOUT;
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
+ return rc;
+ }
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ if (vss->msg_count) {
+ rc = -ETIMEDOUT;
+ } else {
+ vss->pause_restart_state =
+ VIRTSND_PCM_PAUSE_RESTART_RELEASED;
+ vss->prepared = false;
+ vss->stopped = false;
+ rc = 0;
+ }
+ }
+ if (rc)
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
+ return rc;
+ }
+
+ if (state != VIRTSND_PCM_PAUSE_RESTART_PREPARED &&
+ state != VIRTSND_PCM_PAUSE_RESTART_STOPPED) {
+ virtsnd_pcm_pause_restart_fail(vss, true, epoch);
+ return -EIO;
+ }
+
+ rc = virtsnd_pcm_pause_release_flush(vss,
+ BIT(VIRTSND_PCM_PAUSE_RESTART_PREPARED) |
+ BIT(VIRTSND_PCM_PAUSE_RESTART_STOPPED), epoch);
+ if (rc) {
+ if (rc == -ECANCELED)
+ return rc;
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
+ return rc;
+ }
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->prepared = false;
+ vss->stopped = false;
+ }
+
+ return 0;
}
/**
- * virtsnd_pcm_sync_stop() - Synchronous PCM substream stop.
+ * virtsnd_pcm_sync_stop_locked() - Synchronous PCM substream stop.
* @substream: Kernel ALSA substream.
*
* The function can be called both from the upper level or from the driver
@@ -451,7 +1327,7 @@
* Context: Process context. Takes and releases the VirtIO substream spinlock.
* Return: 0 on success, -errno on failure.
*/
-static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream)
+static int virtsnd_pcm_sync_stop_locked(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct virtio_snd *snd = vss->snd;
@@ -459,31 +1335,49 @@
unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
bool need_release;
int rc;
-
- scoped_guard(spinlock_irqsave, &vss->lock) {
+ u64 epoch;
+
+ if (virtsnd_pcm_pause_restart_enabled(vss))
+ return virtsnd_pcm_pause_restart_sync_stop(substream);
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting)
+ return -ECANCELED;
+ epoch = vss->reset_epoch;
vss->xfer_enabled = false;
need_release = vss->release_required;
if (need_release)
vss->stopped = true;
}
cancel_work_sync(&vss->elapsed_period);
+ /* A rejected STOP leaves the device running and must precede RELEASE. */
+ rc = virtsnd_pcm_stop_device(vss, epoch);
+ if (rc) {
+ substream->runtime->stop_operating = true;
+ return rc;
+ }
if (need_release) {
msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_RELEASE,
- GFP_KERNEL);
+ GFP_KERNEL, epoch);
if (!msg) {
substream->runtime->stop_operating = true;
return -ENOMEM;
}
- rc = virtsnd_ctl_msg_send_sync(snd, msg);
+ rc = virtsnd_pcm_send_sync(vss, msg);
if (rc) {
substream->runtime->stop_operating = true;
return rc;
}
- scoped_guard(spinlock_irqsave, &vss->lock)
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
vss->release_required = false;
+ vss->device_running = false;
+ vss->prepared = false;
+ }
}
/*
@@ -492,7 +1386,7 @@
* Thus, we consider the absence of I/O messages in the queue as an
* indication that the substream has been released.
*/
- rc = wait_event_interruptible_timeout(vss->msg_empty,
+ rc = wait_event_timeout(vss->msg_empty,
!virtsnd_pcm_msg_pending_num(vss),
js);
if (rc <= 0) {
@@ -503,8 +1397,12 @@
return !rc ? -ETIMEDOUT : rc;
}
- scoped_guard(spinlock_irqsave, &vss->lock)
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->prepared = false;
vss->stopped = false;
+ }
return 0;
}
@@ -539,10 +1437,62 @@
virtsnd_pcm_cp_pointer(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ size_t hw_ptr = 0;
+ u64 total;
+ bool free_running;
+ bool xrun;
+
+ if (vss->capture_staging) {
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ xrun = vss->xfer_xrun;
+ if (!xrun &&
+ virtsnd_pcm_capture_refresh_mode_locked(vss,
+ &free_running))
+ xrun = true;
+ if (!xrun && !virtsnd_pcm_capture_counters_valid(vss))
+ xrun = true;
+ if (!xrun) {
+ total = vss->capture_callback_snapshot_active ?
+ vss->capture_callback_snapshot :
+ vss->capture_copied_total;
+ /* A full-ring observation gap is modulo-ambiguous. */
+ if (total < vss->capture_pointer_seen_total ||
+ total - vss->capture_pointer_seen_total >=
+ vss->buffer_bytes) {
+ xrun = true;
+ vss->xfer_xrun = true;
+ } else {
+ vss->capture_pointer_seen_total = total;
+ if (vss->capture_reset_observing) {
+ size_t period = snd_pcm_lib_period_bytes(substream);
+
+ vss->capture_acked_total = total;
+ vss->capture_ready = 0;
+ vss->capture_notified_periods =
+ period ? div64_ul(total, period) : 0;
+ }
+ hw_ptr = virtsnd_pcm_ring_offset(total, vss->buffer_bytes);
+ }
+ }
+ if (xrun)
+ vss->xfer_xrun = true;
+ }
+
+ if (xrun)
+ return SNDRV_PCM_POS_XRUN;
+
+ return bytes_to_frames(substream->runtime, hw_ptr);
+ }
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->xfer_xrun)
+ return SNDRV_PCM_POS_XRUN;
+ vss->capture_pointer_seen_total = vss->capture_copied_total;
+ hw_ptr = vss->hw_ptr;
+ }
return snd_pcm_indirect_capture_pointer(substream,
- &vss->pcm_indirect,
- vss->hw_ptr);
+ &vss->pcm_indirect, hw_ptr);
}
struct virtsnd_pcm_transfer {
@@ -557,7 +1507,9 @@
struct virtsnd_pcm_transfer *transfer =
container_of(rec, struct virtsnd_pcm_transfer, indirect);
- if (transfer->error)
+ if (transfer->error ||
+ (substream->stream == SNDRV_PCM_STREAM_CAPTURE &&
+ substream->runtime->state == SNDRV_PCM_STATE_DRAINING))
return;
transfer->error = virtsnd_pcm_msg_send(vss, rec->sw_data, bytes);
@@ -571,7 +1523,7 @@
vss->substream->runtime->stop_operating = true;
}
-static int virtsnd_pcm_pb_ack(struct snd_pcm_substream *substream)
+static int virtsnd_pcm_pb_ack_locked(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
@@ -580,6 +1532,8 @@
scoped_guard(spinlock_irqsave, &queue->lock) {
guard(spinlock)(&vss->lock);
+ if (!vss->prepared)
+ return -EBADFD;
transfer.indirect = vss->pcm_indirect;
if (vss->stopped) {
rc = -EPIPE;
@@ -606,17 +1560,134 @@
return 0;
}
-static int virtsnd_pcm_cp_ack(struct snd_pcm_substream *substream)
+/* The PCM lock is held; exclude every member's buffer reconfiguration. */
+static int virtsnd_pcm_pb_ack(struct snd_pcm_substream *substream)
+{
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ int rc;
+
+ if (!mutex_trylock(&runtime->buffer_mutex))
+ return -EBADFD;
+ rc = virtsnd_pcm_pb_ack_locked(substream);
+ mutex_unlock(&runtime->buffer_mutex);
+ return rc;
+}
+
+static int virtsnd_pcm_capture_staged_ack(struct virtio_pcm_substream *vss,
+ struct snd_pcm_runtime *runtime)
+{
+ struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
+ int rc = 0;
+
+ /*
+ * The RX callback holds the queue lock while draining completions.
+ * Account ALSA's read under the substream lock alone so completions later
+ * in that drain observe the newly released ring space.
+ */
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ snd_pcm_uframes_t appl_ptr;
+ snd_pcm_sframes_t diff;
+ size_t bytes;
+ u64 outstanding;
+ u64 next_acked_total;
+ bool free_running;
+
+ if (!vss->runtime_active || !runtime || !runtime->control ||
+ !runtime->dma_area || vss->suspended)
+ return -EBADFD;
+ if (!vss->prepared && runtime->state != SNDRV_PCM_STATE_DRAINING &&
+ !(runtime->state == SNDRV_PCM_STATE_PAUSED &&
+ virtsnd_pcm_pause_restart_enabled(vss) &&
+ vss->pause_restart_state == VIRTSND_PCM_PAUSE_RESTART_RELEASED))
+ return -EBADFD;
+ if (vss->xfer_xrun)
+ return -EPIPE;
+ rc = virtsnd_pcm_capture_refresh_mode_locked(vss,
+ &free_running);
+ if (rc || !virtsnd_pcm_capture_counters_valid(vss)) {
+ vss->xfer_xrun = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return -EPIPE;
+ }
+
+ appl_ptr = runtime->control->appl_ptr;
+ diff = appl_ptr - vss->pcm_indirect.appl_ptr;
+ if (diff < -(snd_pcm_sframes_t)(runtime->boundary / 2))
+ diff += runtime->boundary;
+ if (diff < 0 ||
+ (snd_pcm_uframes_t)diff > runtime->buffer_size) {
+ vss->xfer_xrun = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return -EPIPE;
+ }
+
+ /* ACK includes any subperiod tail already copied to the ring. */
+ bytes = frames_to_bytes(runtime, diff);
+ outstanding = vss->capture_copied_total -
+ vss->capture_acked_total;
+ if ((!free_running && bytes > vss->capture_ready) ||
+ (free_running &&
+ (bytes > vss->buffer_bytes || bytes > outstanding)) ||
+ check_add_overflow(vss->capture_acked_total, (u64)bytes,
+ &next_acked_total) ||
+ next_acked_total > vss->capture_pointer_seen_total) {
+ vss->xfer_xrun = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return -EPIPE;
+ }
+
+ vss->capture_acked_total = next_acked_total;
+ if (!free_running)
+ vss->capture_ready -= bytes;
+ vss->pcm_indirect.appl_ptr = appl_ptr;
+ }
+
+ /* Preserve the queue -> substream lock order while refilling requests. */
+ scoped_guard(spinlock_irqsave, &queue->lock) {
+ guard(spinlock)(&vss->lock);
+ if (vss->runtime_active && vss->xfer_enabled &&
+ !vss->xfer_xrun) {
+ rc = virtsnd_pcm_capture_send(vss);
+ if (rc) {
+ vss->xfer_xrun = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ }
+ }
+ }
+
+ if (rc)
+ dev_warn_ratelimited(&vss->snd->vdev->dev,
+ "SID %u: failed to refill capture queue after ACK: %d\n",
+ vss->sid, rc);
+
+ /* The ACK is committed; a refill failure is reported by the next XRUN. */
+ return 0;
+}
+
+static int virtsnd_pcm_cp_ack_locked(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
+ struct snd_pcm_runtime *runtime = substream->runtime;
struct virtsnd_pcm_transfer transfer = {};
int rc;
+ if (vss->capture_staging) {
+ rc = virtsnd_pcm_capture_staged_ack(vss, runtime);
+ if (rc == -EPIPE) {
+ guard(spinlock_irqsave)(&vss->lock);
+ virtsnd_pcm_capture_arm_paused_stop(vss);
+ }
+ return rc;
+ }
+
scoped_guard(spinlock_irqsave, &queue->lock) {
guard(spinlock)(&vss->lock);
+ if (!vss->prepared && runtime->state != SNDRV_PCM_STATE_DRAINING)
+ return -EBADFD;
transfer.indirect = vss->pcm_indirect;
- if (vss->stopped) {
+ if (vss->xfer_xrun ||
+ (vss->stopped && runtime->state != SNDRV_PCM_STATE_DRAINING)) {
rc = -EPIPE;
} else {
rc = snd_pcm_indirect_capture_transfer(substream,
@@ -639,6 +1710,50 @@
}
return 0;
+}
+
+/*
+ * Linked prepare locks each member's buffer_mutex, while buffer_accessing is
+ * negative only on its initiating member. ACK must exclude every prepare.
+ * The PCM lock is already held, so a failed trylock must return immediately.
+ */
+static int virtsnd_pcm_cp_ack(struct snd_pcm_substream *substream)
+{
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ int rc;
+
+ if (!mutex_trylock(&runtime->buffer_mutex))
+ return -EBADFD;
+ rc = virtsnd_pcm_cp_ack_locked(substream);
+ mutex_unlock(&runtime->buffer_mutex);
+ return rc;
+}
+
+static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+
+ guard(mutex)(&vss->lifecycle_lock);
+ scoped_guard(pcm_stream_lock_irqsave, substream) {
+ snd_pcm_state_t state = substream->runtime->state;
+
+ /*
+ * Trigger holds the PCM lock through its control requests. Wait
+ * for it, then leave a replacement active generation alone.
+ * lifecycle_lock keeps prepare from replacing an inactive one
+ * until sync_stop_locked has finished its teardown.
+ */
+ if (state == SNDRV_PCM_STATE_RUNNING ||
+ state == SNDRV_PCM_STATE_PAUSED ||
+ state == SNDRV_PCM_STATE_PREPARED ||
+ (state == SNDRV_PCM_STATE_DRAINING &&
+ substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
+ return 0;
+ guard(spinlock_irqsave)(&vss->lock);
+ if (!vss->stopped)
+ return 0;
+ }
+ return virtsnd_pcm_sync_stop_locked(substream);
}
/* PCM substream operators map. */
^ permalink raw reply [flat|nested] 29+ messages in thread* Re: [PATCH v11 09/14] ALSA: virtio: add staged capture accounting and lifecycle recovery
2026-10-31 2:08 ` [PATCH v11 09/14] ALSA: virtio: add staged capture accounting and lifecycle recovery Joonho Lee
@ 2026-10-31 2:51 ` sashiko-bot
0 siblings, 0 replies; 29+ messages in thread
From: sashiko-bot @ 2026-10-31 2:51 UTC (permalink / raw)
To: Joonho Lee, linux-sound; +Cc: virtualization, Michael S. Tsirkin, Eugenio Perez
Thank you for your contribution! Sashiko AI review found 10 potential issue(s) to consider:
- [High] ALSA: virtio: false XRUN on capture drain in virtsnd_pcm_msg_complete()
- [High] ALSA: virtio: buffer_mutex trylock in ack corrupts indirect PCM state
- [High] ALSA: virtio: buffer_mutex trylock in virtsnd_pcm_pb_ack() fails during RESET
- [Medium] ALSA: virtio: staged capture drops RX completions during pause in virtsnd_pcm_capture_complete()
- [Medium] ALSA: virtio: missed XRUN wakeup when RX ring fills during pause in virtsnd_pcm_msg_complete()
- [Medium] ALSA: virtio: virtsnd_pcm_event() skips period work for ordinary capture XRUN events
- [Medium] ALSA: virtio: virtsnd_pcm_start_queue() drops period notifications
- [Medium] ALSA: virtio: failed STOP in virtsnd_pcm_trigger() misses xfer_xrun latch
- [Medium] ALSA: virtio: premature state reset in virtsnd_pcm_prepare_locked()
- [Medium] ALSA: virtio: missing stopped check in virtsnd_pcm_capture_staged_ack()
--
commit 89969d05596ec30bdd3e3e6560275f8867f0911d
Author: Joonho Lee <mynameisjune111@gmail.com>
ALSA: virtio: add staged capture accounting and lifecycle recovery
This commit adds staged capture accounting using request-owned DMA buffers and
monotonic position counters, while separating device running state, RELEASE
obligations, and reset epochs from ALSA runtime state. It also serializes PCM
lifecycle callbacks with lifecycle_lock and updates pause, XRUN, and period
wakeup handling across ordinary and staged capture paths.
Link: https://sashiko.dev/#/patchset/20261030052629.27742-1-mynameisjune111%40gmail.com?part=9
> diff --git a/sound/virtio/virtio_pcm.c b/sound/virtio/virtio_pcm.c
> index be3893de40a55..aed94a892aaa4 100644
> --- a/sound/virtio/virtio_pcm.c
> +++ b/sound/virtio/virtio_pcm.c
[ ... ]
> @@ -517,8 +630,11 @@ void virtsnd_pcm_event(struct virtio_snd *snd, struct virtio_snd_event *event)
> break;
> case VIRTIO_SND_EVT_PCM_XRUN:
> scoped_guard(spinlock, &vss->lock) {
> - if (vss->xfer_enabled)
> + if (vss->xfer_enabled) {
> vss->xfer_xrun = true;
> + if (vss->capture_staging)
> + virtsnd_pcm_schedule_period_elapsed(vss);
> + }
> }
> break;
> }
[Severity: Medium]
When VIRTIO_SND_EVT_PCM_XRUN arrives in virtsnd_pcm_event() while
vss->xfer_enabled is true, why is virtsnd_pcm_schedule_period_elapsed(vss)
only called when vss->capture_staging is set?
In virtsnd_pcm_period_elapsed(), ordinary capture now checks vss->xfer_xrun
and calls snd_pcm_progress_under_stream_lock(substream), which observes
SNDRV_PCM_POS_XRUN from virtsnd_pcm_cp_pointer() and triggers
__snd_pcm_xrun().
However, if the device sends VIRTIO_SND_EVT_PCM_XRUN on an ordinary capture
substream (!vss->capture_staging) and stops completing RX buffers, skipping
virtsnd_pcm_schedule_period_elapsed(vss) here leaves ALSA unaware of the XRUN
until a read timeout expires. Should this check vss->direction ==
SNDRV_PCM_STREAM_CAPTURE instead of vss->capture_staging?
> diff --git a/sound/virtio/virtio_pcm_msg.c b/sound/virtio/virtio_pcm_msg.c
> index b94ab24f5ffef..cdd26729568a1 100644
> --- a/sound/virtio/virtio_pcm_msg.c
> +++ b/sound/virtio/virtio_pcm_msg.c
[ ... ]
> @@ -478,6 +530,290 @@ int virtsnd_pcm_msg_send(struct virtio_pcm_substream *vss, unsigned long offset,
[ ... ]
> +static void virtsnd_pcm_capture_complete(struct virtio_pcm_msg *msg,
> + size_t written_bytes)
> +{
> + struct virtio_pcm_substream *vss = msg->substream;
> + size_t audio_bytes = 0;
> + size_t next_ready = 0;
> + u64 next_copied_total = 0;
> + bool free_running = false;
> + bool got_audio = false;
> +
> + guard(spinlock)(&vss->lock);
> + vss->msg_count--;
> + if (vss->runtime_active && vss->xfer_enabled && !vss->xfer_xrun) {
> + struct snd_pcm_runtime *runtime = vss->substream->runtime;
[Severity: Medium]
In virtsnd_pcm_capture_complete(), does gating completion processing on
vss->xfer_enabled drop in-flight RX completions during a native pause
transition?
When userspace triggers SNDRV_PCM_TRIGGER_PAUSE_PUSH on an active staged
capture stream (with virtsnd_capture_pause_restart disabled),
virtsnd_pcm_trigger() clears vss->xfer_enabled = false under vss->lock while
keeping vss->prepared = true and vss->stopped = false, and then calls
virtsnd_pcm_stop_device() to send VIRTIO_SND_R_PCM_STOP synchronously:
sound/virtio/virtio_pcm_ops.c:virtsnd_pcm_trigger() {
...
case SNDRV_PCM_TRIGGER_STOP:
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
scoped_guard(spinlock_irqsave, &vss->lock) {
if (!vss->prepared)
return 0;
if (command != SNDRV_PCM_TRIGGER_PAUSE_PUSH)
vss->stopped = true;
vss->xfer_enabled = false;
if (!vss->device_running)
return 0;
}
rc = virtsnd_pcm_stop_device(vss, epoch);
}
While VIRTIO_SND_R_PCM_STOP is in flight (both when STOP succeeds and when
the device rejects STOP), the device can complete already-queued RX requests.
Unlike ordinary capture in virtsnd_pcm_msg_complete(), which checks
vss->prepared && !vss->stopped for NOMMU copyout and still updates
vss->hw_ptr, vss->capture_copied_total, and vss->xfer_xrun when
vss->xfer_enabled is false, virtsnd_pcm_capture_complete() skips status
validation, overrun checks, memcpy() into runtime->dma_area, and counter
updates, and then resets msg->length = 0.
When pause is rejected or later resumed via SNDRV_PCM_TRIGGER_PAUSE_RELEASE,
virtsnd_pcm_capture_enqueue() zeroes and re-queues those descriptors,
permanently losing the captured audio frames and any device status or ring
overrun error.
[ ... ]
> @@ -580,14 +924,22 @@ static void virtsnd_pcm_msg_complete(struct virtio_pcm_msg *msg,
> * the actual SG payload capacity before accounting them.
> */
> if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK ||
> - written_bytes <= sizeof(msg->status)) {
> - vss->hw_ptr += msg->length;
> - } else {
> - size_t data_bytes = min_t(size_t,
> - written_bytes - sizeof(msg->status),
> - msg->length);
> -
> - vss->hw_ptr += data_bytes;
> + written_bytes <= sizeof(*msg->status))
> + completed_bytes = msg->length;
> + else
> + completed_bytes = min_t(size_t,
> + written_bytes - sizeof(*msg->status),
> + msg->length);
> + vss->hw_ptr += completed_bytes;
> + if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
> + /* A full unseen ring cannot be represented by the modulo pointer. */
> + if (check_add_overflow(vss->capture_copied_total,
> + (u64)completed_bytes,
> + &vss->capture_copied_total) ||
> + vss->capture_copied_total < vss->capture_pointer_seen_total ||
> + vss->capture_copied_total - vss->capture_pointer_seen_total >=
> + vss->buffer_bytes)
> + vss->xfer_xrun = true;
> }
[Severity: High]
Can this unconditional update of vss->capture_copied_total in
virtsnd_pcm_msg_complete() trigger a false XRUN during capture drain?
When an application calls snd_pcm_drain() (SNDRV_PCM_IOCTL_DRAIN) on a
running ordinary capture stream with unread frames in the buffer,
snd_pcm_do_drain_init() transitions the stream to SNDRV_PCM_STATE_DRAINING
and invokes virtsnd_pcm_trigger(SNDRV_PCM_TRIGGER_STOP), which sets
vss->stopped = true and vss->xfer_enabled = false and sends
VIRTIO_SND_R_PCM_STOP.
In SNDRV_PCM_STATE_DRAINING, snd_pcm_running(substream) is false and
virtsnd_pcm_cp_pointer() is no longer called, so
vss->capture_pointer_seen_total stops advancing. However,
virtsnd_pcm_msg_complete() continues to add completed_bytes (including a full
period msg->length when written_bytes <= sizeof(*msg->status) for empty or
status-only completions) to vss->hw_ptr and vss->capture_copied_total even
when vss->stopped is true.
When the seeded RX ring descriptors complete after STOP or RELEASE,
vss->capture_copied_total - vss->capture_pointer_seen_total reaches
vss->buffer_bytes and latches vss->xfer_xrun = true. Subsequent draining
reads via snd_pcm_readi() or SNDRV_PCM_IOCTL_SYNC_PTR then call
virtsnd_pcm_cp_ack_locked(), which checks:
if (vss->xfer_xrun ||
(vss->stopped && runtime->state != SNDRV_PCM_STATE_DRAINING)) {
rc = -EPIPE;
}
and aborts the capture drain with -EPIPE, discarding the already-captured
audio frames.
> if (vss->hw_ptr >= vss->buffer_bytes)
> @@ -595,7 +947,9 @@ static void virtsnd_pcm_msg_complete(struct virtio_pcm_msg *msg,
>
> msg->length = 0;
>
> - vss->xfer_xrun = false;
> + /* Preserve a latched capture error until prepare recovers it. */
> + if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK)
> + vss->xfer_xrun = false;
> vss->msg_count--;
>
> if (vss->xfer_enabled) {
> @@ -603,8 +957,8 @@ static void virtsnd_pcm_msg_complete(struct virtio_pcm_msg *msg,
>
> runtime->delay =
> bytes_to_frames(runtime,
> - le32_to_cpu(msg->status.latency_bytes));
> - schedule_work(&vss->elapsed_period);
> + le32_to_cpu(msg->status->latency_bytes));
> + virtsnd_pcm_schedule_period_elapsed(vss);
> } else if (!vss->msg_count) {
> wake_up_all(&vss->msg_empty);
> }
[Severity: Medium]
What happens if in-flight ordinary capture RX completions fill the unread
ring while SNDRV_PCM_TRIGGER_PAUSE_PUSH is waiting for VIRTIO_SND_R_PCM_STOP
and the STOP request succeeds?
During SNDRV_PCM_TRIGGER_PAUSE_PUSH, virtsnd_pcm_trigger() clears
vss->xfer_enabled = false before calling virtsnd_pcm_stop_device(vss, epoch).
If the device completes queued RX requests before processing
VIRTIO_SND_R_PCM_STOP and vss->capture_copied_total -
vss->capture_pointer_seen_total reaches vss->buffer_bytes,
virtsnd_pcm_msg_complete() latches vss->xfer_xrun = true, but skips
virtsnd_pcm_schedule_period_elapsed(vss) because vss->xfer_enabled is false.
When virtsnd_pcm_stop_device() returns 0, virtsnd_pcm_trigger() only checks
if (rc && command == SNDRV_PCM_TRIGGER_PAUSE_PUSH) and returns 0 without
scheduling elapsed_period. ALSA transitions runtime->state to
SNDRV_PCM_STATE_PAUSED, and the paused_xrun handler in
virtsnd_pcm_period_elapsed() never runs to move the stream to
SNDRV_PCM_STATE_XRUN, leaving readers in wait_for_avail() sleeping
indefinitely.
> diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
> index ad602b6b6530b..d587c8f699553 100644
> --- a/sound/virtio/virtio_pcm_ops.c
> +++ b/sound/virtio/virtio_pcm_ops.c
[ ... ]
> @@ -320,47 +706,383 @@ static int virtsnd_pcm_prepare(struct snd_pcm_substream *substream)
[ ... ]
> + scoped_guard(spinlock_irqsave, &vss->lock) {
> + if (epoch != vss->reset_epoch || vss->resetting)
> + return -ECANCELED;
> + vss->prepared = false;
> + vss->buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
> + vss->hw_ptr = 0;
> + if (!pause_restart)
> + vss->xfer_xrun = false;
> + vss->suspended = false;
> + vss->msg_count = 0;
> + virtsnd_pcm_msg_reset(vss);
> + memset(&vss->pcm_indirect, 0, sizeof(vss->pcm_indirect));
> + vss->pcm_indirect.sw_buffer_size = vss->buffer_bytes;
> + vss->pcm_indirect.hw_buffer_size = vss->buffer_bytes;
> + if (vss->capture_staging) {
> + vss->capture_boundary = substream->runtime->boundary;
> + rc = virtsnd_pcm_capture_refresh_mode_locked(vss,
> + &free_running);
> + if (rc)
> + return rc;
> + }
> + }
> +
> + rc = virtsnd_pcm_dev_prepare(vss, epoch);
> + scoped_guard(spinlock_irqsave, &vss->lock) {
> + if (epoch != vss->reset_epoch || vss->resetting)
> + return -ECANCELED;
> + vss->prepared = !rc;
> + if (!rc)
> + vss->release_required = true;
> + }
> + if (pause_restart) {
> + if (rc) {
> + if (rc == -ECANCELED)
> + return rc;
> + virtsnd_pcm_pause_restart_fail(vss, false, epoch);
> + } else {
> + scoped_guard(spinlock_irqsave, &vss->lock) {
> + if (vss->resetting || vss->reset_epoch != epoch)
> + return -ECANCELED;
> + vss->stopped = false;
> + vss->xfer_xrun = false;
> + }
> + }
> + }
> +
> + return rc;
> +}
[Severity: Medium]
In virtsnd_pcm_prepare_locked(), if virtsnd_pcm_dev_prepare() fails when
pause_restart is false, doesn't clearing vss->xfer_xrun and resetting
vss->pcm_indirect and the capture counters before sending
VIRTIO_SND_R_PCM_PREPARE leave the driver out of sync with ALSA's runtime
state?
When userspace invokes SNDRV_PCM_IOCTL_PREPARE on a capture substream in
SNDRV_PCM_STATE_XRUN or SNDRV_PCM_STATE_DRAINING, snd_pcm_do_prepare() calls
virtsnd_pcm_prepare_locked(). Before virtsnd_pcm_dev_prepare() is called,
this block clears vss->xfer_xrun = false (when !pause_restart), calls
virtsnd_pcm_msg_reset(vss), and zeroes vss->pcm_indirect.
If virtsnd_pcm_dev_prepare() then returns an error, snd_pcm_do_prepare()
aborts before snd_pcm_do_reset() and snd_pcm_post_prepare(), leaving
runtime->state and runtime->control->appl_ptr unchanged. Because only the
pause_restart branch restores vss->xfer_xrun = true and vss->stopped = true
on failure:
- If the stream was in SNDRV_PCM_STATE_XRUN, the latched vss->xfer_xrun state
is lost even though prepare failed.
- If the stream was in SNDRV_PCM_STATE_DRAINING, runtime->state remains
SNDRV_PCM_STATE_DRAINING with runtime->control->appl_ptr at its pre-prepare
value while vss->pcm_indirect is zeroed and vss->prepared, vss->stopped,
and vss->xfer_xrun are all false; a subsequent read or
SNDRV_PCM_IOCTL_SYNC_PTR in SNDRV_PCM_STATE_DRAINING bypasses the
!vss->prepared and vss->stopped checks in virtsnd_pcm_cp_ack_locked() and
subtracts appl_ptr from a zeroed vss->pcm_indirect.sw_ready.
[ ... ]
> +static int virtsnd_pcm_start_queue(struct virtio_pcm_substream *vss, u64 epoch)
> +{
> + struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
> + int rc = 0;
> +
> + guard(spinlock_irqsave)(&queue->lock);
> + guard(spinlock)(&vss->lock);
> + if (vss->resetting || vss->reset_epoch != epoch)
> + return -ECANCELED;
> + if (vss->stopped || !vss->prepared || vss->xfer_xrun)
> + return vss->xfer_xrun ? -EPIPE : -EBADFD;
> + if (vss->control_uncertain)
> + return -EIO;
> + if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
> + if (vss->capture_staging) {
> + rc = vss->runtime_active ? virtsnd_pcm_capture_send(vss) : -EBADFD;
> + } else if (!vss->capture_rx_seeded) {
> + rc = virtsnd_pcm_msg_send(vss, 0, vss->buffer_bytes);
> + if (!rc)
> + vss->capture_rx_seeded = true;
> + }
> + }
> if (!rc) {
> - guard(spinlock_irqsave)(&vss->lock);
> - vss->release_required = true;
> + if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
> + !vss->capture_staging) {
> + size_t period = snd_pcm_lib_period_bytes(vss->substream);
> +
> + /* A synthetic resume notification is not a new period IRQ. */
> + vss->capture_notified_periods = period ?
> + div64_ul(vss->capture_copied_total, period) : 0;
> + }
> + vss->xfer_enabled = true;
> }
> return rc;
> }
[Severity: Medium]
Does overwriting vss->capture_notified_periods in virtsnd_pcm_start_queue()
drop period notifications for RX periods that completed while
vss->xfer_enabled was false?
During SNDRV_PCM_TRIGGER_PAUSE_PUSH, virtsnd_pcm_trigger() clears
vss->xfer_enabled = false before calling virtsnd_pcm_stop_device(). If one or
more RX periods complete in virtsnd_pcm_msg_complete() while
vss->xfer_enabled is false (either before STOP takes effect or when STOP is
rejected by the device), vss->capture_copied_total advances across a period
boundary without scheduling vss->elapsed_period.
When virtsnd_pcm_start_queue() subsequently runs on rejected PAUSE_PUSH
recovery or on SNDRV_PCM_TRIGGER_PAUSE_RELEASE, it overwrites
vss->capture_notified_periods with div64_ul(vss->capture_copied_total,
period) before virtsnd_pcm_period_elapsed() executes. When
virtsnd_pcm_period_elapsed() then runs:
sound/virtio/virtio_pcm.c:virtsnd_pcm_period_elapsed() {
...
partial = vss->xfer_xrun ||
period_floor <= vss->capture_notified_periods;
if (!partial)
vss->capture_notified_periods = period_floor;
}
period_floor <= vss->capture_notified_periods is forced to true (partial =
true), so it calls snd_pcm_progress_under_stream_lock() instead of
snd_pcm_period_elapsed_under_stream_lock(), losing the period notification,
runtime->hw_ptr_interrupt update, and PCM timer tick for the completed
periods.
> @@ -377,72 +1099,226 @@ static int virtsnd_pcm_prepare(struct snd_pcm_substream *substream)
[ ... ]
> case SNDRV_PCM_TRIGGER_STOP:
> case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> scoped_guard(spinlock_irqsave, &vss->lock) {
> + if (!vss->prepared)
> + return 0;
> if (command != SNDRV_PCM_TRIGGER_PAUSE_PUSH)
> vss->stopped = true;
> vss->xfer_enabled = false;
> + if (!vss->device_running)
> + return 0;
> + }
> +
> + rc = virtsnd_pcm_stop_device(vss, epoch);
> + if (rc && command == SNDRV_PCM_TRIGGER_PAUSE_PUSH) {
> + if (virtsnd_pcm_start_queue(vss, epoch)) {
> + guard(spinlock_irqsave)(&vss->lock);
> + if (vss->reset_epoch == epoch && !vss->resetting) {
> + vss->xfer_xrun = true;
> + vss->stopped = true;
> + substream->runtime->stop_operating = true;
> + virtsnd_pcm_schedule_period_elapsed(vss);
> + }
> + } else if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
> + virtsnd_pcm_schedule_period_elapsed(vss);
> + }
> }
> + return rc;
[Severity: Medium]
If virtsnd_pcm_stop_device() fails during SNDRV_PCM_TRIGGER_STOP on a capture
stream, should vss->xfer_xrun also be latched here?
When userspace invokes SNDRV_PCM_IOCTL_DRAIN on a running capture stream with
unread frames, snd_pcm_do_drain_init() calls snd_pcm_do_stop(substream,
SNDRV_PCM_STATE_DRAINING), which ignores the return value of
substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_STOP) and sets
runtime->state to SNDRV_PCM_STATE_DRAINING.
When virtsnd_pcm_stop_device() fails, vss->device_running remains true.
Unlike virtsnd_pcm_pause_restart_stop(), which calls
virtsnd_pcm_pause_restart_failed() to set vss->xfer_xrun = true, normal-mode
virtsnd_pcm_trigger() only handles rc != 0 for SNDRV_PCM_TRIGGER_PAUSE_PUSH
and leaves vss->xfer_xrun false. Because both virtsnd_pcm_capture_staged_ack()
and virtsnd_pcm_cp_ack_locked() allow ACK in SNDRV_PCM_STATE_DRAINING when
vss->stopped is true unless vss->xfer_xrun is set, draining capture reads and
ACKs can proceed while the device is still running and DMA-writing into the
capture buffer.
[ ... ]
> @@ -606,17 +1560,134 @@ static int virtsnd_pcm_pb_ack(struct snd_pcm_substream *substream)
> return 0;
> }
>
> -static int virtsnd_pcm_cp_ack(struct snd_pcm_substream *substream)
> +/* The PCM lock is held; exclude every member's buffer reconfiguration. */
> +static int virtsnd_pcm_pb_ack(struct snd_pcm_substream *substream)
> +{
> + struct snd_pcm_runtime *runtime = substream->runtime;
> + int rc;
> +
> + if (!mutex_trylock(&runtime->buffer_mutex))
> + return -EBADFD;
> + rc = virtsnd_pcm_pb_ack_locked(substream);
> + mutex_unlock(&runtime->buffer_mutex);
> + return rc;
> +}
[Severity: High]
Can failing mutex_trylock(&runtime->buffer_mutex) in virtsnd_pcm_pb_ack() and
virtsnd_pcm_cp_ack() corrupt vss->pcm_indirect when another thread transiently
holds runtime->buffer_mutex on a running stream?
In sound/core/pcm_native.c, snd_pcm_hw_refine_with_lock(),
snd_pcm_hw_params(), snd_pcm_hw_free(), and snd_pcm_action_nonatomic()
acquire runtime->buffer_mutex via snd_pcm_buffer_access_lock() (or
mutex_lock_nested() on linked group members in snd_pcm_action_group()) before
acquiring the PCM stream lock to check whether runtime->state is
SNDRV_PCM_STATE_RUNNING. Meanwhile, virtsnd_pcm_period_elapsed(),
snd_pcm_status64(), and snd_pcm_sync_ptr() hold the PCM stream lock without
incrementing runtime->buffer_accessing.
If virtsnd_pcm_period_elapsed() or snd_pcm_status64() runs while another
thread holds runtime->buffer_mutex waiting for the PCM stream lock,
virtsnd_pcm_pb_pointer() or virtsnd_pcm_cp_pointer() calls
snd_pcm_indirect_playback_pointer() or snd_pcm_indirect_capture_pointer(),
which first mutates vss->pcm_indirect in place (updating hw_io, hw_ready, and
sw_io) and then invokes substream->ops->ack(substream).
When mutex_trylock(&runtime->buffer_mutex) fails and returns -EBADFD,
snd_pcm_indirect_playback_pointer() and snd_pcm_indirect_capture_pointer()
ignore the error (only checking err == -EPIPE), leaving vss->pcm_indirect
half-updated without running snd_pcm_indirect_playback_transfer() or
snd_pcm_indirect_capture_transfer(). Concurrent SNDRV_PCM_IOCTL_SYNC_PTR
calls without HWSYNC will also fail with -EBADFD whenever another thread is
in the middle of an ioctl that locks buffer_mutex before checking stream
state.
> +
> +static int virtsnd_pcm_capture_staged_ack(struct virtio_pcm_substream *vss,
> + struct snd_pcm_runtime *runtime)
> +{
> + struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
> + int rc = 0;
> +
> + /*
> + * The RX callback holds the queue lock while draining completions.
> + * Account ALSA's read under the substream lock alone so completions later
> + * in that drain observe the newly released ring space.
> + */
> + scoped_guard(spinlock_irqsave, &vss->lock) {
> + snd_pcm_uframes_t appl_ptr;
> + snd_pcm_sframes_t diff;
> + size_t bytes;
> + u64 outstanding;
> + u64 next_acked_total;
> + bool free_running;
> +
> + if (!vss->runtime_active || !runtime || !runtime->control ||
> + !runtime->dma_area || vss->suspended)
> + return -EBADFD;
> + if (!vss->prepared && runtime->state != SNDRV_PCM_STATE_DRAINING &&
> + !(runtime->state == SNDRV_PCM_STATE_PAUSED &&
> + virtsnd_pcm_pause_restart_enabled(vss) &&
> + vss->pause_restart_state == VIRTSND_PCM_PAUSE_RESTART_RELEASED))
> + return -EBADFD;
> + if (vss->xfer_xrun)
> + return -EPIPE;
[Severity: Medium]
Should virtsnd_pcm_capture_staged_ack() also check vss->stopped (or verify
that runtime->state permits acknowledgments), similar to
virtsnd_pcm_cp_ack_locked()?
When ALSA transitions a running staged capture substream to
SNDRV_PCM_STATE_XRUN without the virtio driver setting vss->xfer_xrun (for
example, when snd_pcm_update_state() detects avail >= runtime->stop_threshold,
or when userspace issues SNDRV_PCM_IOCTL_XRUN via snd_pcm_xrun()),
__snd_pcm_xrun() calls snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN), which
invokes virtsnd_pcm_trigger(substream, SNDRV_PCM_TRIGGER_STOP) without
calling snd_pcm_sync_stop(). That sets vss->stopped = true and
vss->xfer_enabled = false while leaving vss->prepared = true and
vss->xfer_xrun = false. Similarly, if SNDRV_PCM_IOCTL_DROP is called while in
SNDRV_PCM_STATE_PREPARED, snd_pcm_do_stop() transitions runtime->state to
SNDRV_PCM_STATE_SETUP without setting stop_operating, leaving vss->prepared =
true.
If userspace then invokes SNDRV_PCM_IOCTL_SYNC_PTR without
SNDRV_PCM_SYNC_PTR_HWSYNC or SNDRV_PCM_SYNC_PTR_APPL, snd_pcm_sync_ptr()
calls pcm_lib_apply_appl_ptr() -> virtsnd_pcm_cp_ack() ->
virtsnd_pcm_capture_staged_ack(). Because virtsnd_pcm_capture_staged_ack()
does not check (vss->stopped && runtime->state != SNDRV_PCM_STATE_DRAINING),
it accepts the ACK and advances vss->capture_acked_total, vss->capture_ready,
and vss->pcm_indirect.appl_ptr while the stream is stopped in
SNDRV_PCM_STATE_XRUN or SNDRV_PCM_STATE_SETUP.
[ ... ]
> @@ -641,6 +1712,50 @@ static int virtsnd_pcm_cp_ack(struct snd_pcm_substream *substream)
> return 0;
> }
>
> +/*
> + * Linked prepare locks each member's buffer_mutex, while buffer_accessing is
> + * negative only on its initiating member. ACK must exclude every prepare.
> + * The PCM lock is already held, so a failed trylock must return immediately.
> + */
> +static int virtsnd_pcm_cp_ack(struct snd_pcm_substream *substream)
> +{
> + struct snd_pcm_runtime *runtime = substream->runtime;
> + int rc;
> +
> + if (!mutex_trylock(&runtime->buffer_mutex))
> + return -EBADFD;
> + rc = virtsnd_pcm_cp_ack_locked(substream);
> + mutex_unlock(&runtime->buffer_mutex);
> + return rc;
> +}
[Severity: High]
Won't mutex_trylock(&runtime->buffer_mutex) in virtsnd_pcm_pb_ack() and
virtsnd_pcm_cp_ack() always fail during SNDRV_PCM_IOCTL_RESET on a running
stream?
When userspace invokes SNDRV_PCM_IOCTL_RESET, snd_pcm_reset() calls
snd_pcm_action_nonatomic(&snd_pcm_action_reset, substream,
ACTION_ARG_IGNORE), which acquires substream->runtime->buffer_mutex via
snd_pcm_buffer_access_lock() (and locks runtime->buffer_mutex on all linked
group members in snd_pcm_action_group()).
While holding runtime->buffer_mutex on the same thread, snd_pcm_do_reset()
calls snd_pcm_lib_ioctl_reset() (or snd_pcm_lib_reset()). When the stream is
running, snd_pcm_lib_ioctl_reset() acquires the PCM stream lock and calls
snd_pcm_update_hw_ptr(substream) -> substream->ops->pointer(substream).
For playback (virtsnd_pcm_pb_pointer()) and ordinary capture
(virtsnd_pcm_cp_pointer()), snd_pcm_indirect_playback_pointer() and
snd_pcm_indirect_capture_pointer() first mutate vss->pcm_indirect in place
(updating hw_io, hw_ready, and sw_io) and then invoke
substream->ops->ack(substream). Because the calling thread already holds
runtime->buffer_mutex, mutex_trylock(&runtime->buffer_mutex) in
virtsnd_pcm_pb_ack() and virtsnd_pcm_cp_ack() is guaranteed to fail and
return -EBADFD.
snd_pcm_indirect_playback_pointer() and snd_pcm_indirect_capture_pointer()
ignore -EBADFD (only checking err == -EPIPE) and skip
snd_pcm_indirect_playback_transfer() / snd_pcm_indirect_capture_transfer()
after vss->pcm_indirect has already been modified. Immediately afterwards,
snd_pcm_post_reset() sets runtime->control->appl_ptr =
runtime->status->hw_ptr without updating vss->pcm_indirect.appl_ptr, causing
the next playback ACK or period completion to compute a negative diff =
runtime->control->appl_ptr - rec->appl_ptr and abort the stream with -EPIPE.
Later commits in this series ("ALSA: pcm: add an optional reset operation
under the stream lock", "ALSA: virtio: synchronize staged capture accounting
during RESET", and "ALSA: virtio: rebase ordinary capture accounting on
RESET") add .reset callbacks for capture streams, but playback streams in
virtsnd_pcm_ops[0] still have no .reset callback or bypass in
virtsnd_pcm_pb_ack(), leaving SNDRV_PCM_IOCTL_RESET broken on running
playback streams.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261031020855.2402-1-mynameisjune111@gmail.com?part=9
^ permalink raw reply [flat|nested] 29+ messages in thread
* [PATCH v11 10/14] ALSA: virtio: prioritize staged capture period work
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (8 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 09/14] ALSA: virtio: add staged capture accounting and lifecycle recovery Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:15 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 11/14] docs: describe virtio-sound capture options Joonho Lee
` (3 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Queue staged capture period notifications on system_highpri_wq through
the common scheduling helper. This allows capture notifications to make
progress when ordinary workqueue workers are delayed by CPU contention.
Playback and ordinary capture keep schedule_work().
This preserves the existing priority proposal without mixing RESET or
lifecycle changes into it. It provides no hard real-time deadline and
cannot prevent a userspace reader from overrunning its buffer.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h
--- a/sound/virtio/virtio_pcm.h
+++ b/sound/virtio/virtio_pcm.h
@@ -161,6 +161,10 @@
static inline bool
virtsnd_pcm_schedule_period_elapsed(struct virtio_pcm_substream *vss)
{
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ vss->capture_staging)
+ return queue_work(system_highpri_wq, &vss->elapsed_period);
+
return schedule_work(&vss->elapsed_period);
}
^ permalink raw reply [flat|nested] 29+ messages in thread* [PATCH v11 11/14] docs: describe virtio-sound capture options
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (9 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 10/14] ALSA: virtio: prioritize staged capture period work Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:16 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 12/14] ALSA: pcm: add an optional reset operation under the stream lock Joonho Lee
` (2 subsequent siblings)
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Document the five opt-in capture module parameters introduced by this
series. All default to false. Describe the startup-empty, short-payload,
packed-status and pause-restart compatibility behavior alongside staging,
and require validation with the target device.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -8328,6 +8328,36 @@
brightness level.
default: 1
+ virtio_snd.capture_allow_empty= [HW,SOUND]
+ Retry a bounded number of empty startup capture replies.
+ Format: <bool>
+ Default: false. Compatibility option for devices that
+ require staged capture; validate with the target device.
+
+ virtio_snd.capture_allow_short= [HW,SOUND]
+ Accept non-empty, frame-aligned short capture replies.
+ Format: <bool>
+ Default: false. Compatibility option for devices that
+ require staged capture; validate with the target device.
+
+ virtio_snd.capture_packed_status= [HW,SOUND]
+ Read status immediately after the returned capture data.
+ Format: <bool>
+ Default: false. Compatibility option for devices that
+ require staged capture; validate with the target device.
+
+ virtio_snd.capture_pause_restart= [HW,SOUND]
+ Release and reprepare capture streams across pause.
+ Format: <bool>
+ Default: false. Compatibility option for devices that
+ require staged capture; validate with the target device.
+
+ virtio_snd.capture_staging= [HW,SOUND]
+ Use request-owned buffers for capture data.
+ Format: <bool>
+ Default: false. Compatibility option for devices that
+ require staged capture; validate with the target device.
+
virtio_mmio.device=
[VMMIO] Memory mapped virtio (platform) device.
^ permalink raw reply [flat|nested] 29+ messages in thread* [PATCH v11 12/14] ALSA: pcm: add an optional reset operation under the stream lock
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (10 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 11/14] docs: describe virtio-sound capture options Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:20 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 13/14] ALSA: virtio: synchronize staged capture accounting during RESET Joonho Lee
2026-10-31 2:08 ` [PATCH v11 14/14] ALSA: virtio: rebase ordinary capture accounting on RESET Joonho Lee
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
A driver may need to synchronize private capture accounting with the
common RESET pointer observation and the core's position rebase.
Add an optional reset operation called under the member's stream lock.
Expose snd_pcm_lib_reset() so the callback can retain common pointer and
time handling. On zero return the core completes that member's rebase
before unlocking it. Drivers without the callback retain the ioctl path.
The operation is also used after a successful prepare.
Zero permits the position rebase; it does not promise XRUN recovery.
A negative return skips the core rebase, so a callback returning an error
must leave coherent pointer state even after partial work.
Linked RESET and prepare stop at the first error without rollback.
Earlier callback members may already have completed. Legacy members keep
the existing post_action policy. Applications must recover the group
after partial failure before relying on shared positions.
This adds an internal kernel operation and no userspace ioctl or layout.
Out-of-tree modules using snd_pcm_ops need to be rebuilt.
Complete appl_ptr rebasing once in the callback path. A later linked
member can sleep in prepare while the earlier member accepts SYNC_PTR;
a subsequent unlocked post_prepare assignment would overwrite that
acknowledgment. Keep explicit RESET playback silence processing and
leave prepare-time filling to the normal START path, preserving samples
written and rewound after prepare.
Atomic and nonatomic synthetic-driver tests exercised both callback and
legacy members, mixed linked groups and later-member failures. The
callback retained an acknowledged appl_ptr of 64, and finite-silence
playback kept the written prefix while clearing the rewound tail.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -77,6 +77,26 @@
unsigned long offset);
int (*mmap)(struct snd_pcm_substream *substream, struct vm_area_struct *vma);
int (*ack)(struct snd_pcm_substream *substream);
+ /*
+ * Optional RESET operation, also used after a successful prepare.
+ * Called with this substream's PCM lock held; atomic streams must not
+ * sleep. Do not reacquire the PCM lock through snd_pcm_lib_ioctl().
+ * snd_pcm_lib_reset() provides the common pointer update under this
+ * lock. The core completes the position and appl_ptr rebase before
+ * unlocking a successful member.
+ *
+ * Return zero to let the core complete the position rebase. As with
+ * the legacy RESET ioctl, zero does not guarantee recovery from XRUN;
+ * callers must still handle the stream state and subsequent I/O errors.
+ * On a negative return the core does not finish the rebase, so the
+ * callback must leave coherent pointer state even after partial work.
+ *
+ * Linked RESET/prepare
+ * stops at the first error without rollback. Earlier callback members
+ * retain their completed reset; legacy members retain the existing
+ * post_action policy. An error does not guarantee unchanged state.
+ */
+ int (*reset)(struct snd_pcm_substream *substream);
};
/*
@@ -1179,6 +1199,7 @@
{
substream->runtime->std_sync_id = true;
}
+int snd_pcm_lib_reset(struct snd_pcm_substream *substream);
int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream,
unsigned int cmd, void *arg);
void snd_pcm_period_elapsed_under_stream_lock(struct snd_pcm_substream *substream);
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1760,20 +1760,39 @@
}
EXPORT_SYMBOL(snd_pcm_hw_params_bits);
-static int snd_pcm_lib_ioctl_reset(struct snd_pcm_substream *substream,
- void *arg)
+/**
+ * snd_pcm_lib_reset - Reset the pointer while holding the PCM stream lock
+ * @substream: PCM substream
+ *
+ * Context: PCM stream lock held. The caller must not hold driver locks
+ * acquired by the pointer or XRUN callbacks.
+ *
+ * Update a running stream through the ordinary pointer path. Other states
+ * start at zero. Pointer errors keep the existing RESET return semantics;
+ * a zero return does not imply recovery from XRUN.
+ * This helper does not update appl_ptr or acquire the stream lock.
+ *
+ * Return: zero.
+ */
+int snd_pcm_lib_reset(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
- guard(pcm_stream_lock_irqsave)(substream);
- if (snd_pcm_running(substream) &&
- snd_pcm_update_hw_ptr(substream) >= 0)
+ if (snd_pcm_running(substream) && snd_pcm_update_hw_ptr(substream) >= 0)
runtime->status->hw_ptr %= runtime->buffer_size;
else {
runtime->status->hw_ptr = 0;
runtime->hw_ptr_wrap = 0;
}
return 0;
+}
+EXPORT_SYMBOL(snd_pcm_lib_reset);
+
+static int snd_pcm_lib_ioctl_reset(struct snd_pcm_substream *substream,
+ void *arg)
+{
+ guard(pcm_stream_lock_irqsave)(substream);
+ return snd_pcm_lib_reset(substream);
}
static int snd_pcm_lib_ioctl_channel_info(struct snd_pcm_substream *substream,
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -1984,11 +1984,35 @@
}
}
-static int snd_pcm_do_reset(struct snd_pcm_substream *substream,
- snd_pcm_state_t state)
+static int snd_pcm_reset_substream(struct snd_pcm_substream *substream,
+ bool for_prepare)
{
struct snd_pcm_runtime *runtime = substream->runtime;
- int err = snd_pcm_ops_ioctl(substream, SNDRV_PCM_IOCTL1_RESET, NULL);
+ int err;
+
+ if (substream->ops->reset) {
+ /*
+ * Complete this member before releasing its PCM lock. A later
+ * linked member may fail; RESET has no group rollback operation.
+ */
+ guard(pcm_stream_lock_irq)(substream);
+
+ err = substream->ops->reset(substream);
+ if (err < 0)
+ return err;
+ runtime->hw_ptr_base = 0;
+ runtime->hw_ptr_interrupt = runtime->status->hw_ptr -
+ runtime->status->hw_ptr % runtime->period_size;
+ runtime->silence_start = runtime->status->hw_ptr;
+ runtime->silence_filled = 0;
+ runtime->control->appl_ptr = runtime->status->hw_ptr;
+ if (!for_prepare && substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
+ runtime->silence_size > 0)
+ snd_pcm_playback_silence(substream, ULONG_MAX);
+ return 0;
+ }
+
+ err = snd_pcm_ops_ioctl(substream, SNDRV_PCM_IOCTL1_RESET, NULL);
if (err < 0)
return err;
guard(pcm_stream_lock_irq)(substream);
@@ -2000,10 +2024,19 @@
return 0;
}
+static int snd_pcm_do_reset(struct snd_pcm_substream *substream,
+ snd_pcm_state_t state)
+{
+ return snd_pcm_reset_substream(substream, false);
+}
+
static void snd_pcm_post_reset(struct snd_pcm_substream *substream,
snd_pcm_state_t state)
{
struct snd_pcm_runtime *runtime = substream->runtime;
+
+ if (substream->ops->reset)
+ return;
guard(pcm_stream_lock_irq)(substream);
runtime->control->appl_ptr = runtime->status->hw_ptr;
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
@@ -2053,14 +2086,16 @@
if (err < 0)
return err;
pcm_qos_req_update(substream, period_to_usecs(substream->runtime));
- return snd_pcm_do_reset(substream, state);
+ return snd_pcm_reset_substream(substream, true);
}
static void snd_pcm_post_prepare(struct snd_pcm_substream *substream,
snd_pcm_state_t state)
{
struct snd_pcm_runtime *runtime = substream->runtime;
- runtime->control->appl_ptr = runtime->status->hw_ptr;
+ /* The reset callback path already completed this rebase under the lock. */
+ if (!substream->ops->reset)
+ runtime->control->appl_ptr = runtime->status->hw_ptr;
snd_pcm_set_state(substream, SNDRV_PCM_STATE_PREPARED);
}
^ permalink raw reply [flat|nested] 29+ messages in thread* Re: [PATCH v11 12/14] ALSA: pcm: add an optional reset operation under the stream lock
2026-10-31 2:08 ` [PATCH v11 12/14] ALSA: pcm: add an optional reset operation under the stream lock Joonho Lee
@ 2026-10-31 2:20 ` sashiko-bot
0 siblings, 0 replies; 29+ messages in thread
From: sashiko-bot @ 2026-10-31 2:20 UTC (permalink / raw)
To: Joonho Lee; +Cc: virtualization, Michael S. Tsirkin, Eugenio Perez
> A driver may need to synchronize private capture accounting with the
> common RESET pointer observation and the core's position rebase.
>
> Add an optional reset operation called under the member's stream lock.
> Expose snd_pcm_lib_reset() so the callback can retain common pointer and
> time handling. On zero return the core completes that member's rebase
> before unlocking it. Drivers without the callback retain the ioctl path.
> The operation is also used after a successful prepare.
>
> Zero permits the position rebase; it does not promise XRUN recovery.
> A negative return skips the core rebase, so a callback returning an error
> must leave coherent pointer state even after partial work.
>
> Linked RESET and prepare stop at the first error without rollback.
> Earlier callback members may already have completed. Legacy members keep
> [ ... ]
> callback retained an acknowledged appl_ptr of 64, and finite-silence
> playback kept the written prefix while clearing the rewound tail.
>
> Assisted-by: LLM
> Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261031020855.2402-1-mynameisjune111@gmail.com?part=12
^ permalink raw reply [flat|nested] 29+ messages in thread
* [PATCH v11 13/14] ALSA: virtio: synchronize staged capture accounting during RESET
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (11 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 12/14] ALSA: pcm: add an optional reset operation under the stream lock Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:42 ` sashiko-bot
2026-10-31 2:08 ` [PATCH v11 14/14] ALSA: virtio: rebase ordinary capture accounting on RESET Joonho Lee
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Use the locked PCM reset operation for staged capture. Reclaim RX space
at the same locked pointer observation used by the common reset and keep
completions arriving after that observation. Rebase the notified-period
counter there to avoid replaying old period notifications.
After common pointer mutation, finish the matching core rebase even if
refill fails. Latch XRUN and schedule notification. RESET can return zero
before the asynchronous error is visible; userspace still needs ordinary
XRUN recovery. A nonblocking read can initially return -EAGAIN and later
-EPIPE. This avoids leaving core and driver positions partly rebased.
A forced 90 ms RX interval reproduced -EPIPE with the earlier accounting.
The corrected sequence matched the next 48,000 deterministic frames and
passed reopen. Linked RESET and prepare partial-failure fixtures also
passed with atomic and nonatomic stream locking.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
--- a/sound/virtio/virtio_pcm_ops.c
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -9,6 +9,7 @@
#include "virtio_card.h"
+static const struct snd_pcm_ops virtsnd_pcm_capture_staged_ops;
bool virtsnd_capture_staging;
module_param_named(capture_staging, virtsnd_capture_staging, bool, 0444);
@@ -392,6 +393,10 @@
}
}
+ /* Keep RESET operation selection fixed for the opened runtime. */
+ substream->ops = vss->capture_staging ?
+ &virtsnd_pcm_capture_staged_ops :
+ &virtsnd_pcm_ops[substream->stream];
snd_pcm_hw_constraint_integer(substream->runtime,
SNDRV_PCM_HW_PARAM_PERIODS);
@@ -1754,6 +1759,61 @@
return 0;
}
return virtsnd_pcm_sync_stop_locked(substream);
+}
+
+/* The core holds the stream lock through the matching appl_ptr reset. */
+static int virtsnd_pcm_reset(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
+ size_t position;
+ size_t period;
+ int rc;
+
+ /* Reclaim RX space atomically with the pointer observation. */
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ vss->capture_reset_observing = true;
+ rc = snd_pcm_lib_reset(substream);
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ vss->capture_reset_observing = false;
+ if (rc || !vss->capture_staging)
+ return rc;
+
+ guard(spinlock_irqsave)(&queue->lock);
+ guard(spinlock)(&vss->lock);
+ if (vss->resetting)
+ return 0;
+ /* The common reset has already handled a pointer-reported XRUN. */
+ if (vss->xfer_xrun)
+ return 0;
+ if (snd_pcm_running(substream)) {
+ /* Keep completions arriving after the core's pointer observation. */
+ vss->capture_acked_total = vss->capture_pointer_seen_total;
+ vss->capture_ready = vss->capture_free_running ? 0 :
+ vss->capture_copied_total - vss->capture_acked_total;
+ } else {
+ position = frames_to_bytes(runtime, runtime->status->hw_ptr);
+ vss->hw_ptr = position;
+ period = snd_pcm_lib_period_bytes(substream);
+ vss->capture_copied_total = position;
+ vss->capture_acked_total = position;
+ vss->capture_pointer_seen_total = position;
+ vss->capture_ready = 0;
+ vss->capture_notified_periods = period ? position / period : 0;
+ }
+ vss->capture_callback_snapshot = 0;
+ vss->capture_callback_snapshot_active = false;
+ vss->pcm_indirect.appl_ptr = runtime->status->hw_ptr;
+ if (snd_pcm_running(substream) && vss->xfer_enabled && vss->prepared) {
+ rc = virtsnd_pcm_capture_send(vss);
+ if (rc) {
+ vss->xfer_xrun = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ }
+ }
+ /* Complete the matching core pointer rebase before reporting XRUN. */
+ return 0;
}
/* PCM substream operators map. */
@@ -1783,3 +1843,18 @@
.ack = virtsnd_pcm_cp_ack,
},
};
+
+/* Selected at open; the staging policy remains fixed for that runtime. */
+static const struct snd_pcm_ops virtsnd_pcm_capture_staged_ops = {
+ .open = virtsnd_pcm_open,
+ .close = virtsnd_pcm_close,
+ .ioctl = snd_pcm_lib_ioctl,
+ .reset = virtsnd_pcm_reset,
+ .hw_params = virtsnd_pcm_hw_params,
+ .hw_free = virtsnd_pcm_hw_free,
+ .prepare = virtsnd_pcm_prepare,
+ .trigger = virtsnd_pcm_trigger,
+ .sync_stop = virtsnd_pcm_sync_stop,
+ .pointer = virtsnd_pcm_cp_pointer,
+ .ack = virtsnd_pcm_cp_ack,
+};
^ permalink raw reply [flat|nested] 29+ messages in thread* Re: [PATCH v11 13/14] ALSA: virtio: synchronize staged capture accounting during RESET
2026-10-31 2:08 ` [PATCH v11 13/14] ALSA: virtio: synchronize staged capture accounting during RESET Joonho Lee
@ 2026-10-31 2:42 ` sashiko-bot
0 siblings, 0 replies; 29+ messages in thread
From: sashiko-bot @ 2026-10-31 2:42 UTC (permalink / raw)
To: Joonho Lee; +Cc: virtualization, Michael S. Tsirkin, Eugenio Perez
> Use the locked PCM reset operation for staged capture. Reclaim RX space
> at the same locked pointer observation used by the common reset and keep
> completions arriving after that observation. Rebase the notified-period
> counter there to avoid replaying old period notifications.
>
> After common pointer mutation, finish the matching core rebase even if
> refill fails. Latch XRUN and schedule notification. RESET can return zero
> before the asynchronous error is visible; userspace still needs ordinary
> XRUN recovery. A nonblocking read can initially return -EAGAIN and later
> -EPIPE. This avoids leaving core and driver positions partly rebased.
>
> A forced 90 ms RX interval reproduced -EPIPE with the earlier accounting.
> The corrected sequence matched the next 48,000 deterministic frames and
> passed reopen. Linked RESET and prepare partial-failure fixtures also
> passed with atomic and nonatomic stream locking.
>
> Assisted-by: LLM
> Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261031020855.2402-1-mynameisjune111@gmail.com?part=13
^ permalink raw reply [flat|nested] 29+ messages in thread
* [PATCH v11 14/14] ALSA: virtio: rebase ordinary capture accounting on RESET
2026-10-31 2:08 [PATCH v11 00/14] ALSA: virtio: staged capture recovery and PCM RESET synchronization Joonho Lee
` (12 preceding siblings ...)
2026-10-31 2:08 ` [PATCH v11 13/14] ALSA: virtio: synchronize staged capture accounting during RESET Joonho Lee
@ 2026-10-31 2:08 ` Joonho Lee
2026-10-31 2:40 ` sashiko-bot
13 siblings, 1 reply; 29+ messages in thread
From: Joonho Lee @ 2026-10-31 2:08 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Ordinary capture's indirect positions must follow the common RESET
observation while preserving the device's fixed DMA ring offsets. Select
its reset callback at open alongside the staged capture callback.
Suppress nested ACK refills during snd_pcm_lib_reset(). For paused
capture, hold the RX queue and substream locks while checking lifecycle
state and observing the latest completed position. Update a local copy
of the indirect state, return discarded RX space, and commit on success.
This also keeps the observation boundary consistent with a late RX
completion. Data arriving after the committed observation remains unread.
Honor an existing XRUN before changing private paused accounting or
refilling descriptors. On a refill failure, retain the error and complete
the core rebase; the worker then reports XRUN. RESET can return zero while
the error notification is pending. Prepare or reopen recovers the stream.
Device reset suppresses fresh notifications until a usable queue exists.
Set the ordinary notification floor to the RESET observation so queued
work cannot report a discarded period as new progress. Native resume
preserves the RX ring ownership established by the earlier patches.
Fault tests covered late completions, existing XRUN, nested refill and
refill failures with recovery and reopen. Ordinary and staged 70-second
RW and MMAP captures matched the deterministic sequence, including
PAUSE, RESET, resume and the intended discard boundary. The paused
interleaving test verifies the atomic observation boundary; it does not
establish sample loss in the original implementation.
Link: https://sashiko.dev/#/patchset/20261030052629.27742-1-mynameisjune111%40gmail.com?part=14
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h
--- a/sound/virtio/virtio_pcm.h
+++ b/sound/virtio/virtio_pcm.h
@@ -76,6 +76,8 @@
* @release_required: Successful PREPARE still needs a successful RELEASE.
* @control_uncertain: Native control result requires device reset before reuse.
* @capture_reset_observing: Reclaim staged samples during RESET pointer capture.
+ * @indirect_reset_observing: Suppress ordinary ACK refill during RESET pointer
+ * capture; protected by the PCM stream lock.
* @suspended: True if the substream is suspended and must be reconfigured on
* the device side at resume.
* @pause_restart_state: Device-side state for opt-in pause compatibility.
@@ -127,6 +129,7 @@
bool release_required;
bool control_uncertain;
bool capture_reset_observing;
+ bool indirect_reset_observing;
bool suspended;
enum virtio_pcm_pause_restart_state pause_restart_state;
struct virtio_pcm_msg **msgs;
diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
--- a/sound/virtio/virtio_pcm_ops.c
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -10,6 +10,7 @@
#include "virtio_card.h"
static const struct snd_pcm_ops virtsnd_pcm_capture_staged_ops;
+static const struct snd_pcm_ops virtsnd_pcm_capture_indirect_ops;
bool virtsnd_capture_staging;
module_param_named(capture_staging, virtsnd_capture_staging, bool, 0444);
@@ -398,6 +399,9 @@
&virtsnd_pcm_capture_staged_ops :
&virtsnd_pcm_ops[substream->stream];
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE && !vss->capture_staging)
+ substream->ops = &virtsnd_pcm_capture_indirect_ops;
+
snd_pcm_hw_constraint_integer(substream->runtime,
SNDRV_PCM_HW_PARAM_PERIODS);
@@ -1724,9 +1728,13 @@
*/
static int virtsnd_pcm_cp_ack(struct snd_pcm_substream *substream)
{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
int rc;
+ /* RESET observes the pointer before returning discarded RX space. */
+ if (vss->indirect_reset_observing)
+ return 0;
if (!mutex_trylock(&runtime->buffer_mutex))
return -EBADFD;
rc = virtsnd_pcm_cp_ack_locked(substream);
@@ -1759,6 +1767,89 @@
return 0;
}
return virtsnd_pcm_sync_stop_locked(substream);
+}
+
+/*
+ * The PCM lock covers indirect accounting and core completion. Once lib_reset
+ * changes hw_ptr, complete the core rebase even if refilling fails. The latched
+ * XRUN rejects subsequent pointer/ACK operations; the worker publishes XRUN to
+ * paused streams too. RESET success therefore does not imply stream recovery.
+ */
+static int virtsnd_pcm_indirect_reset(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
+ struct virtsnd_pcm_transfer transfer = {};
+ snd_pcm_uframes_t paused_ptr = 0;
+ bool paused = runtime->state == SNDRV_PCM_STATE_PAUSED;
+ int rc;
+
+ /* Only PCM-locked callbacks access this observation flag. */
+ vss->indirect_reset_observing = true;
+ rc = snd_pcm_lib_reset(substream);
+ vss->indirect_reset_observing = false;
+ if (rc)
+ return rc;
+ guard(spinlock_irqsave)(&queue->lock);
+ guard(spinlock)(&vss->lock);
+ if (vss->resetting)
+ return 0;
+ if (vss->xfer_xrun) {
+ virtsnd_pcm_transfer_failed(vss);
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return 0;
+ }
+ if (!snd_pcm_running(substream) && !paused)
+ return 0;
+ if (!vss->prepared || vss->stopped) {
+ virtsnd_pcm_transfer_failed(vss);
+ vss->xfer_xrun = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return 0;
+ }
+
+ transfer.indirect = vss->pcm_indirect;
+ if (paused) {
+ /* Observe and reclaim paused completions in one queue transaction. */
+ vss->capture_pointer_seen_total = vss->capture_copied_total;
+ vss->indirect_reset_observing = true;
+ paused_ptr = snd_pcm_indirect_capture_pointer(substream,
+ &transfer.indirect, vss->hw_ptr);
+ vss->indirect_reset_observing = false;
+ if (paused_ptr == SNDRV_PCM_POS_XRUN) {
+ virtsnd_pcm_transfer_failed(vss);
+ vss->xfer_xrun = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return 0;
+ }
+ runtime->status->hw_ptr = paused_ptr;
+ }
+ transfer.indirect.sw_ready = 0;
+ /* Consume no application delta while returning discarded RX space. */
+ transfer.indirect.appl_ptr = runtime->control->appl_ptr;
+ rc = snd_pcm_indirect_capture_transfer(substream, &transfer.indirect,
+ virtsnd_pcm_trans_copy);
+ if (!rc)
+ rc = transfer.error;
+ if (rc) {
+ virtsnd_pcm_transfer_failed(vss);
+ vss->xfer_xrun = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return 0;
+ }
+
+ /* RESET discards all samples through the observed software pointer. */
+ transfer.indirect.sw_ready = 0;
+ transfer.indirect.appl_ptr = runtime->status->hw_ptr;
+ vss->pcm_indirect = transfer.indirect;
+ {
+ size_t period = snd_pcm_lib_period_bytes(substream);
+
+ vss->capture_notified_periods = period ?
+ div64_ul(vss->capture_pointer_seen_total, period) : 0;
+ }
+ return 0;
}
/* The core holds the stream lock through the matching appl_ptr reset. */
@@ -1858,3 +1949,17 @@
.pointer = virtsnd_pcm_cp_pointer,
.ack = virtsnd_pcm_cp_ack,
};
+
+static const struct snd_pcm_ops virtsnd_pcm_capture_indirect_ops = {
+ .open = virtsnd_pcm_open,
+ .close = virtsnd_pcm_close,
+ .ioctl = snd_pcm_lib_ioctl,
+ .reset = virtsnd_pcm_indirect_reset,
+ .hw_params = virtsnd_pcm_hw_params,
+ .hw_free = virtsnd_pcm_hw_free,
+ .prepare = virtsnd_pcm_prepare,
+ .trigger = virtsnd_pcm_trigger,
+ .sync_stop = virtsnd_pcm_sync_stop,
+ .pointer = virtsnd_pcm_cp_pointer,
+ .ack = virtsnd_pcm_cp_ack,
+};
^ permalink raw reply [flat|nested] 29+ messages in thread* Re: [PATCH v11 14/14] ALSA: virtio: rebase ordinary capture accounting on RESET
2026-10-31 2:08 ` [PATCH v11 14/14] ALSA: virtio: rebase ordinary capture accounting on RESET Joonho Lee
@ 2026-10-31 2:40 ` sashiko-bot
0 siblings, 0 replies; 29+ messages in thread
From: sashiko-bot @ 2026-10-31 2:40 UTC (permalink / raw)
To: Joonho Lee, linux-sound; +Cc: virtualization, Michael S. Tsirkin, Eugenio Perez
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] ALSA: virtio: stale pcm_indirect state after RESET in PREPARED state
--
commit c77024b62d8010ad66e1fdcc36816a226c5bcfcc
Author: Joonho Lee <mynameisjune111@gmail.com>
ALSA: virtio: rebase ordinary capture accounting on RESET
This commit introduces virtsnd_pcm_indirect_reset() and
virtsnd_pcm_capture_indirect_ops to rebase ordinary capture indirect
positions and return discarded RX space when SNDRV_PCM_IOCTL_RESET is
called. It also suppresses nested ACK refills during the RESET pointer
observation and updates the period notification floor.
Link: https://sashiko.dev/#/patchset/20261030052629.27742-1-mynameisjune111%40gmail.com?part=14
> diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
> index f350d0c753763..9af0813acd77a 100644
> --- a/sound/virtio/virtio_pcm_ops.c
> +++ b/sound/virtio/virtio_pcm_ops.c
[ ... ]
> @@ -1761,6 +1769,89 @@ static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream)
> return virtsnd_pcm_sync_stop_locked(substream);
> }
>
> +/*
> + * The PCM lock covers indirect accounting and core completion. Once lib_reset
> + * changes hw_ptr, complete the core rebase even if refilling fails. The latched
> + * XRUN rejects subsequent pointer/ACK operations; the worker publishes XRUN to
> + * paused streams too. RESET success therefore does not imply stream recovery.
> + */
> +static int virtsnd_pcm_indirect_reset(struct snd_pcm_substream *substream)
> +{
> + struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
> + struct snd_pcm_runtime *runtime = substream->runtime;
> + struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
> + struct virtsnd_pcm_transfer transfer = {};
> + snd_pcm_uframes_t paused_ptr = 0;
> + bool paused = runtime->state == SNDRV_PCM_STATE_PAUSED;
> + int rc;
> +
> + /* Only PCM-locked callbacks access this observation flag. */
> + vss->indirect_reset_observing = true;
> + rc = snd_pcm_lib_reset(substream);
> + vss->indirect_reset_observing = false;
> + if (rc)
> + return rc;
> + guard(spinlock_irqsave)(&queue->lock);
> + guard(spinlock)(&vss->lock);
> + if (vss->resetting)
> + return 0;
> + if (vss->xfer_xrun) {
> + virtsnd_pcm_transfer_failed(vss);
> + virtsnd_pcm_schedule_period_elapsed(vss);
> + return 0;
> + }
> + if (!snd_pcm_running(substream) && !paused)
> + return 0;
[Severity: Medium]
Can returning early here when the substream is in SNDRV_PCM_STATE_PREPARED
leave vss->pcm_indirect.appl_ptr and vss->pcm_indirect.sw_ready out of sync
with runtime->control->appl_ptr?
While in SNDRV_PCM_STATE_PREPARED (where vss->prepared is true and
vss->stopped is false), userspace can invoke SNDRV_PCM_IOCTL_SYNC_PTR
without SNDRV_PCM_SYNC_PTR_APPL to advance appl_ptr to N:
snd_pcm_sync_ptr()
pcm_lib_apply_appl_ptr()
virtsnd_pcm_cp_ack()
virtsnd_pcm_cp_ack_locked()
snd_pcm_indirect_capture_transfer()
which sets vss->pcm_indirect.appl_ptr = N and
vss->pcm_indirect.sw_ready = -frames_to_bytes(runtime, N).
If userspace then calls SNDRV_PCM_IOCTL_RESET in SNDRV_PCM_STATE_PREPARED,
snd_pcm_lib_reset() sets runtime->status->hw_ptr = 0,
virtsnd_pcm_indirect_reset() returns 0 early without updating
vss->pcm_indirect, and snd_pcm_reset_substream() resets
runtime->control->appl_ptr = runtime->status->hw_ptr (0).
When the stream is subsequently started and virtsnd_pcm_cp_pointer() or
virtsnd_pcm_cp_ack() runs before appl_ptr reaches N,
snd_pcm_indirect_capture_transfer() sees diff = appl_ptr - rec->appl_ptr < 0:
if (diff) {
if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2))
diff += runtime->boundary;
if (diff < 0)
return -EPIPE;
causing a false -EPIPE XRUN and a dev_err() message in
virtsnd_pcm_cp_ack_locked().
Should virtsnd_pcm_indirect_reset() also reset vss->pcm_indirect.sw_ready = 0
and vss->pcm_indirect.appl_ptr = runtime->status->hw_ptr when not running or
paused, similar to how virtsnd_pcm_reset() updates
vss->pcm_indirect.appl_ptr = runtime->status->hw_ptr?
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261031020855.2402-1-mynameisjune111@gmail.com?part=14
^ permalink raw reply [flat|nested] 29+ messages in thread