* [PATCH v25 01/16] ALSA: pcm: mark stop-threshold accesses for capture policy sampling
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 02/16] ALSA: pcm: report partial progress under the stream lock Joonho Lee
` (14 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 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
staged-capture policy sampling.
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>
---
sound/core/oss/pcm_oss.c | 2 +-
sound/core/pcm.c | 3 ++-
sound/core/pcm_native.c | 5 +++--
3 files changed, 6 insertions(+), 4 deletions(-)
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] 21+ messages in thread* [PATCH v25 02/16] ALSA: pcm: report partial progress under the stream lock
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
2026-11-11 2:56 ` [PATCH v25 01/16] ALSA: pcm: mark stop-threshold accesses for capture policy sampling Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 03/16] ALSA: pcm: add an optional reset operation " Joonho Lee
` (13 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Allow a driver to publish subperiod progress under the PCM stream lock
without generating a period timer notification. Use the ordinary pointer
update, XRUN and wakeup path. Capture DRAINING can publish its final
tail while playback and other inactive states retain their existing
behavior.
Handle capture DRAINING separately in the state update: a full buffer is
still readable capture data, while progress beyond the buffer capacity
is an overrun. Playback continues to finish draining when its buffer is
empty.
Refresh capture availability after the unlocked copy and application
pointer commit while DRAINING. A final tail can arrive during the copy;
subtracting only the copied frames from the earlier snapshot can
otherwise finish draining with unread samples left in the ring.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
include/sound/pcm.h | 1 +
sound/core/pcm_lib.c | 40 +++++++++++++++++++++++++++++++++++++---
2 files changed, 38 insertions(+), 3 deletions(-)
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
@@ -215,8 +215,14 @@
if (avail > runtime->avail_max)
runtime->avail_max = avail;
if (runtime->state == SNDRV_PCM_STATE_DRAINING) {
- if (avail >= runtime->buffer_size) {
- snd_pcm_drain_done(substream);
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+ if (avail >= runtime->buffer_size) {
+ snd_pcm_drain_done(substream);
+ return -EPIPE;
+ }
+ } else if (avail > runtime->buffer_size) {
+ /* A full capture buffer remains readable while draining. */
+ __snd_pcm_xrun(substream);
return -EPIPE;
}
} else {
@@ -1919,6 +1925,30 @@
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. Capture
+ * streams may report their final tail while DRAINING. 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))
+ return;
+ if (!snd_pcm_running(substream) &&
+ !(substream->stream == SNDRV_PCM_STREAM_CAPTURE &&
+ substream->runtime->state == SNDRV_PCM_STATE_DRAINING))
+ 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.
@@ -2405,7 +2435,11 @@
offset += frames;
size -= frames;
xfer += frames;
- avail -= frames;
+ if (!is_playback &&
+ runtime->state == SNDRV_PCM_STATE_DRAINING)
+ avail = snd_pcm_avail(substream);
+ else
+ avail -= frames;
if (is_playback &&
runtime->state == SNDRV_PCM_STATE_PREPARED &&
snd_pcm_playback_hw_avail(runtime) >= (snd_pcm_sframes_t)runtime->start_threshold) {
^ permalink raw reply [flat|nested] 21+ messages in thread* [PATCH v25 03/16] ALSA: pcm: add an optional reset operation under the stream lock
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
2026-11-11 2:56 ` [PATCH v25 01/16] ALSA: pcm: mark stop-threshold accesses for capture policy sampling Joonho Lee
2026-11-11 2:56 ` [PATCH v25 02/16] ALSA: pcm: report partial progress under the stream lock Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 04/16] ALSA: pcm: notify drivers after linked prepare completes Joonho Lee
` (12 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 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.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
include/sound/pcm.h | 21 +++++++++++++++++++++
sound/core/pcm_lib.c | 29 ++++++++++++++++++++++++-----
sound/core/pcm_native.c | 45 ++++++++++++++++++++++++++++++++++++++++-----
3 files changed, 85 insertions(+), 10 deletions(-)
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
@@ -1766,20 +1766,39 @@
}
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] 21+ messages in thread* [PATCH v25 04/16] ALSA: pcm: notify drivers after linked prepare completes
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (2 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 03/16] ALSA: pcm: add an optional reset operation " Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 4:00 ` sashiko-bot
2026-11-11 2:56 ` [PATCH v25 05/16] ALSA: pcm: serialize linked buffer actions Joonho Lee
` (11 subsequent siblings)
15 siblings, 1 reply; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
A linked prepare can finish one member before another member's driver
prepare or reset fails. Drivers that admit transfers after their own
prepare callback can then accept an ACK while the group action is still
incomplete.
Add an optional prepare_complete callback. After all sleeping prepare
and reset actions have succeeded, take the group and member PCM locks,
publish every PREPARED state, and notify opted-in drivers before
releasing those locks. Keep the buffer locks and access gates held
throughout the operation. A concurrent DROP observes the group before or
after this commit point.
On a driver error, notify only the attempted prefix, including the
failing member. Opted-in members in that prefix return to SETUP. Leave
unreached members untouched. Preflight failures have no completion
callback. Preserve SUSPENDED and DISCONNECTED states if finalization
finds either in the affected group or prefix. Successful driver actions
canceled by such a state return -ESTRPIPE or -EBADFD, respectively. A
driver error keeps its original return value. DISCONNECTED takes
precedence when a linked group contains both terminal states.
Do not generate a stop-timer event while closing prepare admission.
Ordinary legacy drivers keep their existing successful preparation and
pointer rebasing. The new callback runs with the group and member locks
held and must neither sleep nor acquire another PCM stream lock.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
include/sound/pcm.h | 17 +++++
sound/core/pcm_native.c | 152 +++++++++++++++++++++++++++++++++++++++++------
2 files changed, 149 insertions(+), 20 deletions(-)
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -77,6 +77,23 @@
unsigned long offset);
int (*mmap)(struct snd_pcm_substream *substream, struct vm_area_struct *vma);
int (*ack)(struct snd_pcm_substream *substream);
+ /*
+ * Optional prepare completion notification. Called while the core holds
+ * all linked PCM stream locks, after prepare/reset actions succeed or stop
+ * at the first error. On success, the core publishes PREPARED for every
+ * member before calling this with true. If any member is DISCONNECTED or
+ * SUSPENDED, all states are preserved and opted-in members receive false.
+ * On failure, called with false for opted-in members whose action ran,
+ * including the failing member. Their state becomes SETUP unless any member
+ * in that prefix is DISCONNECTED or SUSPENDED; then all prefix states are
+ * preserved. Members not reached and pre-action failures receive no
+ * callback. Standalone RESET does not call this callback. It must not sleep
+ * or acquire another PCM stream lock.
+ * A terminal-state cancellation returns -EBADFD for DISCONNECTED or
+ * -ESTRPIPE for SUSPENDED.
+ */
+ void (*prepare_complete)(struct snd_pcm_substream *substream,
+ bool success);
/*
* Optional RESET operation, also used after a successful prepare.
* Called with this substream's PCM lock held; atomic streams must not
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
@@ -1310,6 +1310,10 @@
snd_pcm_state_t state);
void (*post_action)(struct snd_pcm_substream *substream,
snd_pcm_state_t state);
+ int (*finish_action)(struct snd_pcm_substream *substream,
+ snd_pcm_state_t state, bool success,
+ struct snd_pcm_substream *failed_substream,
+ bool stream_lock);
};
/*
@@ -1350,12 +1354,19 @@
ops->undo_action(s1, state);
}
}
+ if (ops->finish_action) {
+ ops->finish_action(substream, state, false, s,
+ stream_lock);
+ }
s = NULL; /* unlock all */
goto _unlock;
}
}
- snd_pcm_group_for_each_entry(s, substream) {
- ops->post_action(s, state);
+ if (ops->finish_action) {
+ res = ops->finish_action(substream, state, true, NULL, stream_lock);
+ } else {
+ snd_pcm_group_for_each_entry(s, substream)
+ ops->post_action(s, state);
}
_unlock:
/* unlock streams */
@@ -1379,7 +1390,8 @@
*/
static int snd_pcm_action_single(const struct action_ops *ops,
struct snd_pcm_substream *substream,
- snd_pcm_state_t state)
+ snd_pcm_state_t state,
+ bool stream_lock)
{
int res;
@@ -1387,10 +1399,19 @@
if (res < 0)
return res;
res = ops->do_action(substream, state);
- if (res == 0)
- ops->post_action(substream, state);
- else if (ops->undo_action)
- ops->undo_action(substream, state);
+ if (res == 0) {
+ if (ops->finish_action)
+ res = ops->finish_action(substream, state, true, NULL,
+ stream_lock);
+ else
+ ops->post_action(substream, state);
+ } else {
+ if (ops->undo_action)
+ ops->undo_action(substream, state);
+ if (ops->finish_action)
+ ops->finish_action(substream, state, false, substream,
+ stream_lock);
+ }
return res;
}
@@ -1469,7 +1490,7 @@
if (group)
res = snd_pcm_action_group(ops, substream, state, true);
else
- res = snd_pcm_action_single(ops, substream, state);
+ res = snd_pcm_action_single(ops, substream, state, true);
snd_pcm_group_unref(group, substream);
return res;
}
@@ -1501,7 +1522,7 @@
if (snd_pcm_stream_linked(substream))
res = snd_pcm_action_group(ops, substream, state, false);
else
- res = snd_pcm_action_single(ops, substream, state);
+ res = snd_pcm_action_single(ops, substream, state, false);
snd_pcm_buffer_access_unlock(substream->runtime);
return res;
}
@@ -1660,7 +1681,7 @@
int snd_pcm_drain_done(struct snd_pcm_substream *substream)
{
return snd_pcm_action_single(&snd_pcm_action_stop, substream,
- SNDRV_PCM_STATE_SETUP);
+ SNDRV_PCM_STATE_SETUP, true);
}
/**
@@ -2063,9 +2084,12 @@
static int snd_pcm_pre_prepare(struct snd_pcm_substream *substream,
snd_pcm_state_t state)
{
- snd_pcm_state_t cur_state = snd_pcm_get_state(substream);
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ snd_pcm_state_t cur_state;
int f_flags = state;
+ guard(pcm_stream_lock_irq)(substream);
+ cur_state = runtime->state;
if (cur_state == SNDRV_PCM_STATE_OPEN ||
cur_state == SNDRV_PCM_STATE_DISCONNECTED)
return -EBADFD;
@@ -2089,20 +2113,108 @@
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;
- /* 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);
+static int snd_pcm_finish_prepare(struct snd_pcm_substream *substream,
+ snd_pcm_state_t state, bool success,
+ struct snd_pcm_substream *failed_substream,
+ bool stream_lock)
+{
+ struct snd_pcm_substream *s;
+ struct snd_pcm_group *group = NULL;
+ bool cancel = false;
+ int cancel_err = 0;
+ int depth = 1;
+
+ if (!stream_lock) {
+ snd_pcm_stream_lock_irq(substream);
+ group = snd_pcm_stream_group_ref(substream);
+ if (group) {
+ snd_pcm_group_for_each_entry(s, substream) {
+ if (s == substream)
+ continue;
+ if (s->pcm->nonatomic)
+ mutex_lock_nested(&s->self_group.mutex, depth);
+ else
+ spin_lock_nested(&s->self_group.lock, depth);
+ depth++;
+ }
+ }
+ }
+
+ /* Preserve terminal states instead of publishing a partial group commit. */
+ snd_pcm_group_for_each_entry(s, substream) {
+ struct snd_pcm_runtime *runtime = s->runtime;
+
+ if (runtime->state == SNDRV_PCM_STATE_DISCONNECTED) {
+ cancel = true;
+ cancel_err = -EBADFD;
+ } else if (runtime->state == SNDRV_PCM_STATE_SUSPENDED) {
+ cancel = true;
+ if (!cancel_err)
+ cancel_err = -ESTRPIPE;
+ }
+ if (!success && s == failed_substream)
+ break;
+ }
+
+ if (success && !cancel) {
+ snd_pcm_group_for_each_entry(s, substream) {
+ struct snd_pcm_runtime *runtime = s->runtime;
+
+ /* The reset callback path already completed this rebase. */
+ if (!s->ops->reset)
+ runtime->control->appl_ptr = runtime->status->hw_ptr;
+ __snd_pcm_set_state(runtime, SNDRV_PCM_STATE_PREPARED);
+ }
+ } else if (!success && !cancel) {
+ snd_pcm_group_for_each_entry(s, substream) {
+ struct snd_pcm_runtime *runtime = s->runtime;
+
+ if (s->ops->prepare_complete &&
+ runtime->state != SNDRV_PCM_STATE_SETUP)
+ __snd_pcm_set_state(runtime, SNDRV_PCM_STATE_SETUP);
+ if (s == failed_substream)
+ break;
+ }
+ }
+
+ if (!success || cancel) {
+ snd_pcm_group_for_each_entry(s, substream) {
+ wake_up(&s->runtime->sleep);
+ wake_up(&s->runtime->tsleep);
+ if (!success && s == failed_substream)
+ break;
+ }
+ }
+
+ /* Publish all states before any driver observes completion. */
+ snd_pcm_group_for_each_entry(s, substream) {
+ if (s->ops->prepare_complete)
+ s->ops->prepare_complete(s, success && !cancel);
+ if (!success && s == failed_substream)
+ break;
+ }
+
+ if (!stream_lock) {
+ if (group) {
+ snd_pcm_group_for_each_entry(s, substream) {
+ if (s == substream)
+ continue;
+ if (s->pcm->nonatomic)
+ mutex_unlock(&s->self_group.mutex);
+ else
+ spin_unlock(&s->self_group.lock);
+ }
+ snd_pcm_group_unref(group, substream);
+ }
+ snd_pcm_stream_unlock_irq(substream);
+ }
+ return success && cancel ? cancel_err : 0;
}
static const struct action_ops snd_pcm_action_prepare = {
.pre_action = snd_pcm_pre_prepare,
.do_action = snd_pcm_do_prepare,
- .post_action = snd_pcm_post_prepare
+ .finish_action = snd_pcm_finish_prepare
};
/**
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH v25 04/16] ALSA: pcm: notify drivers after linked prepare completes
2026-11-11 2:56 ` [PATCH v25 04/16] ALSA: pcm: notify drivers after linked prepare completes Joonho Lee
@ 2026-11-11 4:00 ` sashiko-bot
0 siblings, 0 replies; 21+ messages in thread
From: sashiko-bot @ 2026-11-11 4:00 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 to consider:
- [Medium] ALSA: pcm: state desync on opted-in streams in
snd_pcm_finish_prepare()
--
commit a91218e64a7e783b333a467d7102781bb84f7f64
Author: Joonho Lee <mynameisjune111@gmail.com>
ALSA: pcm: notify drivers after linked prepare completes
This commit adds an optional prepare_complete callback to snd_pcm_ops and
defers publishing SNDRV_PCM_STATE_PREPARED until all linked prepare and
reset actions finish under the stream locks.
> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> index a547ac720b518..f98eb3329f2de 100644
> --- a/sound/core/pcm_native.c
> +++ b/sound/core/pcm_native.c
[ ... ]
> @@ -2089,20 +2113,108 @@ static int snd_pcm_do_prepare(struct snd_pcm_substream *substream,
> return snd_pcm_reset_substream(substream, true);
> }
>
> -static void snd_pcm_post_prepare(struct snd_pcm_substream *substream,
> - snd_pcm_state_t state)
> +static int snd_pcm_finish_prepare(struct snd_pcm_substream *substream,
> + snd_pcm_state_t state, bool success,
> + struct snd_pcm_substream *failed_substream,
> + bool stream_lock)
> {
[ ... ]
> + /* Preserve terminal states instead of publishing a partial group commit. */
> + snd_pcm_group_for_each_entry(s, substream) {
> + struct snd_pcm_runtime *runtime = s->runtime;
> +
> + if (runtime->state == SNDRV_PCM_STATE_DISCONNECTED) {
> + cancel = true;
> + cancel_err = -EBADFD;
> + } else if (runtime->state == SNDRV_PCM_STATE_SUSPENDED) {
> + cancel = true;
> + if (!cancel_err)
> + cancel_err = -ESTRPIPE;
> + }
> + if (!success && s == failed_substream)
> + break;
> + }
> +
> + if (success && !cancel) {
> + snd_pcm_group_for_each_entry(s, substream) {
> + struct snd_pcm_runtime *runtime = s->runtime;
> +
> + /* The reset callback path already completed this rebase. */
> + if (!s->ops->reset)
> + runtime->control->appl_ptr = runtime->status->hw_ptr;
> + __snd_pcm_set_state(runtime, SNDRV_PCM_STATE_PREPARED);
> + }
> + } else if (!success && !cancel) {
> + snd_pcm_group_for_each_entry(s, substream) {
> + struct snd_pcm_runtime *runtime = s->runtime;
> +
> + if (s->ops->prepare_complete &&
> + runtime->state != SNDRV_PCM_STATE_SETUP)
> + __snd_pcm_set_state(runtime, SNDRV_PCM_STATE_SETUP);
> + if (s == failed_substream)
> + break;
> + }
> + }
> +
> + if (!success || cancel) {
> + snd_pcm_group_for_each_entry(s, substream) {
> + wake_up(&s->runtime->sleep);
> + wake_up(&s->runtime->tsleep);
> + if (!success && s == failed_substream)
> + break;
> + }
> + }
> +
> + /* Publish all states before any driver observes completion. */
> + snd_pcm_group_for_each_entry(s, substream) {
> + if (s->ops->prepare_complete)
> + s->ops->prepare_complete(s, success && !cancel);
> + if (!success && s == failed_substream)
> + break;
> + }
[Severity: Medium]
Can gating the SNDRV_PCM_STATE_SETUP rollback on !cancel leave healthy
opted-in streams in SNDRV_PCM_STATE_PREPARED after calling
prepare_complete(s, false)?
When a linked group is re-prepared from SNDRV_PCM_STATE_PREPARED and one
member's PCM device disconnects during snd_pcm_do_prepare(),
snd_pcm_dev_disconnect() marks only that device's substreams as
SNDRV_PCM_STATE_DISCONNECTED because the streams are not running.
snd_pcm_finish_prepare() then sets cancel = true, skips resetting the other
opted-in members to SNDRV_PCM_STATE_SETUP, and still calls
s->ops->prepare_complete(s, false) on them.
That revokes driver preparation while runtime->state (or
runtime->suspended_state if the stream was suspended during
snd_pcm_do_prepare()) remains SNDRV_PCM_STATE_PREPARED in the ALSA core,
so once the disconnected sibling is unlinked or closed, later START or ACK
calls pass core state checks and fail in the driver. Should each opted-in
member in the affected group or prefix that is not itself DISCONNECTED or
SUSPENDED be reset to SNDRV_PCM_STATE_SETUP whenever !success || cancel
(and have runtime->suspended_state updated to SNDRV_PCM_STATE_SETUP if
suspended)?
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261111025655.63951-1-mynameisjune111@gmail.com?part=4
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH v25 05/16] ALSA: pcm: serialize linked buffer actions
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (3 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 04/16] ALSA: pcm: notify drivers after linked prepare completes Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 06/16] ALSA: virtio: propagate playback send failures through ACK Joonho Lee
` (10 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Concurrent non-atomic actions on different members of a linked PCM group
currently lock their own buffer first, then the other members. That
acquisition order can differ between callers. Sibling buffer mutexes
also do not close their buffer-access admission counters.
Close buffer access for every member before taking any buffer mutex, and
acquire those mutexes in the stable linked-list order while group
membership is protected. Release every access gate on success and on
failure, including when a member already has an active buffer access.
The group action then uses the buffers already held by its caller.
The PCM stream and group locks are not held across sleeping driver
prepare callbacks. Single-stream non-atomic actions keep their existing
buffer-access locking path.
Fixes: 3c3201f8c7bb ("ALSA: pcm: Fix races among concurrent prepare and hw_params/hw_free calls")
Fixes: bc55cfd5718c ("ALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock")
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
sound/core/pcm_native.c | 71 +++++++++++++++++++++++++++++++++++++----------
1 file changed, 56 insertions(+), 15 deletions(-)
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
@@ -731,6 +731,44 @@
{
mutex_unlock(&runtime->buffer_mutex);
atomic_inc(&runtime->buffer_accessing);
+}
+
+/* Gate all linked buffers before taking their mutexes in group-list order. */
+static int snd_pcm_group_buffer_access_lock(struct snd_pcm_substream *substream)
+{
+ struct snd_pcm_substream *s, *s1;
+ int depth = 0;
+
+ snd_pcm_group_for_each_entry(s, substream) {
+ if (!atomic_dec_unless_positive(&s->runtime->buffer_accessing)) {
+ snd_pcm_group_for_each_entry(s1, substream) {
+ if (s1 == s)
+ break;
+ atomic_inc(&s1->runtime->buffer_accessing);
+ }
+ return -EBUSY;
+ }
+ }
+
+ snd_pcm_group_for_each_entry(s, substream) {
+ if (depth == 0)
+ mutex_lock(&s->runtime->buffer_mutex);
+ else
+ mutex_lock_nested(&s->runtime->buffer_mutex, depth);
+ depth++;
+ }
+
+ return 0;
+}
+
+static void snd_pcm_group_buffer_access_unlock(struct snd_pcm_substream *substream)
+{
+ struct snd_pcm_substream *s;
+
+ list_for_each_entry_reverse(s, &substream->group->substreams, link_list)
+ mutex_unlock(&s->runtime->buffer_mutex);
+ snd_pcm_group_for_each_entry(s, substream)
+ atomic_inc(&s->runtime->buffer_accessing);
}
/* fill the PCM buffer with the current silence format; called from pcm_oss.c */
@@ -1317,9 +1355,9 @@
};
/*
- * this functions is core for handling of linked stream
- * Note: the stream state might be changed also on failure
- * Note2: call with calling stream lock + link lock
+ * Handle an action on all linked streams.
+ * When stream_lock is true, the caller holds the calling stream and group
+ * locks. Otherwise, the caller holds link_rwsem and every group buffer_mutex.
*/
static int snd_pcm_action_group(const struct action_ops *ops,
struct snd_pcm_substream *substream,
@@ -1331,10 +1369,8 @@
int res = 0, depth = 1;
snd_pcm_group_for_each_entry(s, substream) {
- if (s != substream) {
- if (!stream_lock)
- mutex_lock_nested(&s->runtime->buffer_mutex, depth);
- else if (s->pcm->nonatomic)
+ if (s != substream && stream_lock) {
+ if (s->pcm->nonatomic)
mutex_lock_nested(&s->self_group.mutex, depth);
else
spin_lock_nested(&s->self_group.lock, depth);
@@ -1371,10 +1407,8 @@
_unlock:
/* unlock streams */
snd_pcm_group_for_each_entry(s1, substream) {
- if (s1 != substream) {
- if (!stream_lock)
- mutex_unlock(&s1->runtime->buffer_mutex);
- else if (s1->pcm->nonatomic)
+ if (s1 != substream && stream_lock) {
+ if (s1->pcm->nonatomic)
mutex_unlock(&s1->self_group.mutex);
else
spin_unlock(&s1->self_group.lock);
@@ -1512,18 +1546,25 @@
struct snd_pcm_substream *substream,
snd_pcm_state_t state)
{
+ bool linked;
int res;
/* Guarantee the group members won't change during non-atomic action */
guard(rwsem_read)(&snd_pcm_link_rwsem);
- res = snd_pcm_buffer_access_lock(substream->runtime);
+ linked = snd_pcm_stream_linked(substream);
+ if (linked)
+ res = snd_pcm_group_buffer_access_lock(substream);
+ else
+ res = snd_pcm_buffer_access_lock(substream->runtime);
if (res < 0)
return res;
- if (snd_pcm_stream_linked(substream))
+ if (linked) {
res = snd_pcm_action_group(ops, substream, state, false);
- else
+ snd_pcm_group_buffer_access_unlock(substream);
+ } else {
res = snd_pcm_action_single(ops, substream, state, false);
- snd_pcm_buffer_access_unlock(substream->runtime);
+ snd_pcm_buffer_access_unlock(substream->runtime);
+ }
return res;
}
^ permalink raw reply [flat|nested] 21+ messages in thread* [PATCH v25 06/16] ALSA: virtio: propagate playback send failures through ACK
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (4 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 05/16] ALSA: pcm: serialize linked buffer actions Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 07/16] ALSA: virtio: Recover PCM state after a failed start Joonho Lee
` (9 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Propagate playback submission failures through ACK and commit indirect
accounting only after transport submission succeeds. Keep the PCM state
and buffer-access checks synchronized with playback transfer admission.
The existing capture ACK callback and initial queue reservation behavior
remain together until the request-owned capture conversion in patch 12.
That conversion introduces RX reservation, validation and refill as one
contract.
Fixes: fe981e67568c ("ALSA: virtio: use ack callback")
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
sound/virtio/virtio_pcm.h | 6 +
sound/virtio/virtio_pcm_msg.c | 12 ++
sound/virtio/virtio_pcm_ops.c | 237 ++++++++++++++++++++++++++++++++++++-----
3 files changed, 228 insertions(+), 27 deletions(-)
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
@@ -33,6 +33,10 @@
* @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.
+ * @prepared: True after device PREPARE and the core pointer reset succeed;
+ * protected by @lock.
+ * @preparing: ACK gate through teardown and prepare's core reset;
+ * 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 +60,8 @@
bool xfer_enabled;
bool xfer_xrun;
bool stopped;
+ bool prepared;
+ bool preparing;
bool suspended;
struct virtio_pcm_msg **msgs;
unsigned int nmsgs;
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
@@ -97,6 +97,38 @@
static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream);
/**
+ * virtsnd_pcm_close_ack() - Update PCM prepare admission state.
+ * @substream: Kernel ALSA substream.
+ * @preparing: True while driver prepare and the core pointer reset are active.
+ *
+ * Context: Process context.
+ */
+static void virtsnd_pcm_close_ack(struct snd_pcm_substream *substream,
+ bool preparing)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+
+ scoped_guard(pcm_stream_lock_irqsave, substream) {
+ guard(spinlock_irqsave)(&vss->lock);
+ vss->prepared = false;
+ vss->xfer_enabled = false;
+ vss->preparing = preparing;
+ }
+}
+
+/* Keep completed RX data valid while RELEASE drains the device queue. */
+static void virtsnd_pcm_block_ack(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+
+ scoped_guard(pcm_stream_lock_irqsave, substream) {
+ guard(spinlock_irqsave)(&vss->lock);
+ vss->preparing = true;
+ vss->xfer_enabled = false;
+ }
+}
+
+/**
* virtsnd_pcm_open() - Open the PCM substream.
* @substream: Kernel ALSA substream.
*
@@ -115,7 +147,8 @@
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;
/*
@@ -219,6 +252,8 @@
struct virtio_device *vdev = vss->snd->vdev;
int rc;
+ virtsnd_pcm_close_ack(substream, false);
+
if (virtsnd_pcm_msg_pending_num(vss)) {
dev_err(&vdev->dev, "SID %u: invalid I/O queue state\n",
vss->sid);
@@ -254,6 +289,8 @@
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ virtsnd_pcm_close_ack(substream, 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);
@@ -262,17 +299,18 @@
}
/**
- * virtsnd_pcm_prepare() - Prepare the PCM substream.
+ * virtsnd_pcm_prepare_device() - Prepare the PCM substream on the device.
* @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_device(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;
+ int rc;
if (!vss->suspended) {
if (virtsnd_pcm_msg_pending_num(vss)) {
@@ -287,16 +325,14 @@
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);
+ runtime->channels,
+ runtime->format, runtime->rate);
if (rc)
return rc;
}
- vss->xfer_xrun = false;
vss->suspended = false;
vss->msg_count = 0;
virtsnd_pcm_msg_reset(vss);
@@ -311,7 +347,33 @@
if (!msg)
return -ENOMEM;
- return virtsnd_ctl_msg_send_sync(vss->snd, msg);
+ rc = virtsnd_ctl_msg_send_sync(vss->snd, msg);
+ if (rc)
+ return rc;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->xfer_xrun = false;
+ }
+ return 0;
+}
+
+/* Keep ACK closed through the core's locked pointer reset. */
+static int virtsnd_pcm_prepare(struct snd_pcm_substream *substream)
+{
+ virtsnd_pcm_close_ack(substream, true);
+ return virtsnd_pcm_prepare_device(substream);
+}
+
+/* Complete admission only after the linked core prepare action ends. */
+static void virtsnd_pcm_prepare_complete(
+ struct snd_pcm_substream *substream, bool success)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->prepared = success;
+ vss->preparing = false;
+ }
}
/**
@@ -338,6 +400,8 @@
scoped_guard(spinlock_irqsave, &queue->lock) {
guard(spinlock)(&vss->lock);
+ if (vss->preparing || !vss->prepared)
+ return -EBADFD;
if (vss->direction == SNDRV_PCM_STREAM_CAPTURE)
rc = virtsnd_pcm_msg_send(vss, 0, vss->buffer_bytes);
if (rc)
@@ -356,10 +420,12 @@
return virtsnd_ctl_msg_send_sync(snd, msg);
case SNDRV_PCM_TRIGGER_SUSPEND:
- vss->suspended = true;
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ vss->suspended = true;
fallthrough;
case SNDRV_PCM_TRIGGER_STOP:
- vss->stopped = true;
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ vss->stopped = true;
fallthrough;
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
scoped_guard(spinlock_irqsave, &vss->lock) {
@@ -393,11 +459,16 @@
struct virtio_snd *snd = vss->snd;
struct virtio_snd_msg *msg;
unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
+ bool stopped;
int rc;
+ virtsnd_pcm_block_ack(substream);
+
cancel_work_sync(&vss->elapsed_period);
- if (!vss->stopped)
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ stopped = vss->stopped;
+ if (!stopped)
return 0;
msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_RELEASE,
@@ -425,7 +496,8 @@
return !rc ? -ETIMEDOUT : rc;
}
- vss->stopped = false;
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ vss->stopped = false;
return 0;
}
@@ -442,6 +514,10 @@
virtsnd_pcm_pb_pointer(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ if (vss->xfer_xrun)
+ return SNDRV_PCM_POS_XRUN;
return snd_pcm_indirect_playback_pointer(substream,
&vss->pcm_indirect,
@@ -461,41 +537,144 @@
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ if (vss->xfer_xrun)
+ return SNDRV_PCM_POS_XRUN;
+
return snd_pcm_indirect_capture_pointer(substream,
&vss->pcm_indirect,
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);
+ 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->xfer_xrun = true;
+ vss->substream->runtime->stop_operating = true;
+}
+
+/* The caller holds the PCM lock, also used by DROP and state transitions. */
+static int virtsnd_pcm_ack_state(struct snd_pcm_substream *substream)
+{
+ switch (substream->runtime->state) {
+ case SNDRV_PCM_STATE_XRUN:
+ /* The member is already XRUN; avoid stopping its linked group twice. */
+ return -EBADFD;
+ case SNDRV_PCM_STATE_PREPARED:
+ case SNDRV_PCM_STATE_RUNNING:
+ case SNDRV_PCM_STATE_PAUSED:
+ case SNDRV_PCM_STATE_DRAINING:
+ if (atomic_read(&substream->runtime->buffer_accessing) < 0)
+ return -EBADFD;
+ return 0;
+ default:
+ return -EBADFD;
+ }
+}
+
+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);
+ struct virtsnd_pcm_transfer transfer = {};
+ int rc;
+
+ rc = virtsnd_pcm_ack_state(substream);
+ if (rc)
+ return rc;
+
+ scoped_guard(spinlock_irqsave, &queue->lock) {
+ guard(spinlock)(&vss->lock);
+ if (vss->preparing || !vss->prepared)
+ return -EBADFD;
+ if (vss->stopped)
+ return -EBADFD;
+ if (vss->xfer_xrun) {
+ rc = -EPIPE;
+ } else {
+ transfer.indirect = vss->pcm_indirect;
+ 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);
+ return -EPIPE;
+ }
+
+ return 0;
+}
+
+static void virtsnd_pcm_legacy_capture_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);
}
-static int virtsnd_pcm_pb_ack(struct snd_pcm_substream *substream)
+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);
-
+ int rc;
+
+ rc = virtsnd_pcm_ack_state(substream);
+ if (rc)
+ return rc;
guard(spinlock_irqsave)(&queue->lock);
guard(spinlock)(&vss->lock);
-
- return snd_pcm_indirect_playback_transfer(substream, &vss->pcm_indirect,
- virtsnd_pcm_trans_copy);
-}
-
-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);
+ if (vss->preparing || !vss->prepared)
+ return -EBADFD;
+ if (vss->xfer_xrun)
+ return -EPIPE;
+ if (vss->stopped &&
+ substream->runtime->state != SNDRV_PCM_STATE_DRAINING)
+ return -EBADFD;
return snd_pcm_indirect_capture_transfer(substream, &vss->pcm_indirect,
- virtsnd_pcm_trans_copy);
+ virtsnd_pcm_legacy_capture_copy);
+}
+
+/**
+ * virtsnd_pcm_reset() - Reset PCM pointers.
+ * @substream: Kernel ALSA substream.
+ *
+ * Context: PCM stream lock held.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_pcm_reset(struct snd_pcm_substream *substream)
+{
+ return snd_pcm_lib_reset(substream);
}
/* PCM substream operators map. */
@@ -507,6 +686,8 @@
.hw_params = virtsnd_pcm_hw_params,
.hw_free = virtsnd_pcm_hw_free,
.prepare = virtsnd_pcm_prepare,
+ .prepare_complete = virtsnd_pcm_prepare_complete,
+ .reset = virtsnd_pcm_reset,
.trigger = virtsnd_pcm_trigger,
.sync_stop = virtsnd_pcm_sync_stop,
.pointer = virtsnd_pcm_pb_pointer,
@@ -519,6 +700,8 @@
.hw_params = virtsnd_pcm_hw_params,
.hw_free = virtsnd_pcm_hw_free,
.prepare = virtsnd_pcm_prepare,
+ .prepare_complete = virtsnd_pcm_prepare_complete,
+ .reset = virtsnd_pcm_reset,
.trigger = virtsnd_pcm_trigger,
.sync_stop = virtsnd_pcm_sync_stop,
.pointer = virtsnd_pcm_cp_pointer,
^ permalink raw reply [flat|nested] 21+ messages in thread* [PATCH v25 07/16] ALSA: virtio: Recover PCM state after a failed start
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (5 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 06/16] ALSA: virtio: propagate playback send failures through ACK Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 08/16] ALSA: virtio: Retain queued messages through device reset Joonho Lee
` (8 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 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.
Latch a transfer XRUN in both playback and capture, and schedule the
existing period worker so a running or draining core stream sees the
pointer error. This also retires a failed playback START during drain,
where drain-init can already have advanced the core state to DRAINING.
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>
---
sound/virtio/virtio_pcm.h | 6 +-
sound/virtio/virtio_pcm_ops.c | 113 +++++++++++++++++++++++++++++++----------
2 files changed, 89 insertions(+), 30 deletions(-)
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.
* @prepared: True after device PREPARE and the core pointer reset succeed;
* protected by @lock.
* @preparing: ACK gate through teardown and prepare's core reset;
@@ -62,6 +62,8 @@
bool stopped;
bool prepared;
bool preparing;
+ /* 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
@@ -116,6 +116,17 @@
}
}
+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->xfer_xrun = true;
+ }
+ vss->substream->runtime->stop_operating = true;
+ schedule_work(&vss->elapsed_period);
+}
+
/* Keep completed RX data valid while RELEASE drains the device queue. */
static void virtsnd_pcm_block_ack(struct snd_pcm_substream *substream)
{
@@ -148,7 +159,7 @@
SNDRV_PCM_HW_PARAM_PERIODS);
scoped_guard(spinlock_irqsave, &vss->lock)
- vss->stopped = !!vss->msg_count;
+ vss->stopped |= !!vss->msg_count;
vss->suspended = false;
/*
@@ -250,13 +261,26 @@
{
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;
virtsnd_pcm_close_ack(substream, false);
- 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);
+ scoped_guard(pcm_stream_lock_irqsave, substream)
+ substream->runtime->stop_operating = true;
return -EBADFD;
}
@@ -310,7 +334,18 @@
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);
+ scoped_guard(pcm_stream_lock_irqsave, substream)
+ substream->runtime->stop_operating = true;
+ return -EBADFD;
+ }
if (!vss->suspended) {
if (virtsnd_pcm_msg_pending_num(vss)) {
@@ -353,6 +388,7 @@
scoped_guard(spinlock_irqsave, &vss->lock) {
vss->xfer_xrun = false;
+ vss->release_required = true;
}
return 0;
}
@@ -402,33 +438,40 @@
guard(spinlock)(&vss->lock);
if (vss->preparing || !vss->prepared)
return -EBADFD;
+ 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)
- return rc;
- vss->xfer_enabled = true;
+ if (!rc)
+ vss->xfer_enabled = true;
+ }
+ if (rc) {
+ virtsnd_pcm_start_failed(vss);
+ return rc;
}
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:
- scoped_guard(spinlock_irqsave, &vss->lock)
- vss->suspended = true;
+ vss->suspended = true;
fallthrough;
case SNDRV_PCM_TRIGGER_STOP:
- scoped_guard(spinlock_irqsave, &vss->lock)
- 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;
}
@@ -459,26 +502,38 @@
struct virtio_snd *snd = vss->snd;
struct virtio_snd_msg *msg;
unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
- bool stopped;
+ bool need_release;
int rc;
virtsnd_pcm_block_ack(substream);
+ 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);
- scoped_guard(spinlock_irqsave, &vss->lock)
- stopped = vss->stopped;
- if (!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) {
+ scoped_guard(pcm_stream_lock_irqsave, substream)
+ substream->runtime->stop_operating = true;
+ return -ENOMEM;
+ }
+
+ rc = virtsnd_ctl_msg_send_sync(snd, msg);
+ if (rc) {
+ scoped_guard(pcm_stream_lock_irqsave, substream)
+ 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
@@ -492,6 +547,8 @@
if (rc <= 0) {
dev_warn(&snd->vdev->dev, "SID %u: failed to flush I/O queue\n",
vss->sid);
+ scoped_guard(pcm_stream_lock_irqsave, substream)
+ substream->runtime->stop_operating = true;
return !rc ? -ETIMEDOUT : rc;
}
^ permalink raw reply [flat|nested] 21+ messages in thread* [PATCH v25 08/16] ALSA: virtio: Retain queued messages through device reset
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (6 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 07/16] ALSA: virtio: Recover PCM state after a failed start Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 09/16] ALSA: virtio: bound PCM transfers and retain DMA buffers Joonho Lee
` (7 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 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.
Protect event callback admission with the event queue lock. Disabling
events waits for an active dispatch, and later callbacks see a closed
gate before ALSA objects are freed. Enable and pending-event draining
share the same lock.
Reclaim pending event buffers after a failed probe without dispatching
notifications into ALSA objects that have not been constructed. Record
the queue's prior enabled state under its lock before closing admission.
Track successful virtqueue initialization so teardown and failed restore
cleanup call del_vqs() only for an initialized queue set.
Fixes: 9d45e514da88 ("ALSA: virtio: handling control messages")
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
sound/virtio/virtio_card.c | 110 ++++++++++++++++++++++++++++++++---------
sound/virtio/virtio_card.h | 6 ++
sound/virtio/virtio_ctl_msg.c | 64 +++++++++++++++++++++---
sound/virtio/virtio_ctl_msg.h | 4 +
sound/virtio/virtio_pcm.h | 2 +
sound/virtio/virtio_pcm_msg.c | 42 ++++++++++++++--
6 files changed, 193 insertions(+), 35 deletions(-)
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
@@ -70,23 +70,13 @@
}
}
-/**
- * virtsnd_event_notify_cb() - Dispatch all reported events from the event queue.
- * @vqueue: Underlying event virtqueue.
- *
- * This callback function is called upon a vring interrupt request from the
- * device.
- *
- * Context: Interrupt context.
- */
-static void virtsnd_event_notify_cb(struct virtqueue *vqueue)
-{
- struct virtio_snd *snd = vqueue->vdev->priv;
- struct virtio_snd_queue *queue = virtsnd_event_queue(snd);
+static void virtsnd_event_drain_locked(struct virtio_snd *snd,
+ struct virtqueue *vqueue)
+{
struct virtio_snd_event *event;
u32 length;
- guard(spinlock_irqsave)(&queue->lock);
+ lockdep_assert_held(&virtsnd_event_queue(snd)->lock);
do {
virtqueue_disable_cb(vqueue);
while ((event = virtqueue_get_buf(vqueue, &length))) {
@@ -94,6 +84,26 @@
virtsnd_event_send(vqueue, event, true, GFP_ATOMIC);
}
} while (!virtqueue_enable_cb(vqueue));
+}
+
+/**
+ * virtsnd_event_notify_cb() - Dispatch all reported events from the event queue.
+ * @vqueue: Underlying event virtqueue.
+ *
+ * This callback function is called upon a vring interrupt request from the
+ * device.
+ *
+ * Context: Interrupt context.
+ */
+static void virtsnd_event_notify_cb(struct virtqueue *vqueue)
+{
+ struct virtio_snd *snd = vqueue->vdev->priv;
+ struct virtio_snd_queue *queue = virtsnd_event_queue(snd);
+
+ guard(spinlock_irqsave)(&queue->lock);
+ if (queue->vqueue != vqueue || !snd->event_vq_enabled)
+ return;
+ virtsnd_event_drain_locked(snd, vqueue);
}
/**
@@ -131,6 +141,7 @@
for (i = 0; i < VIRTIO_SND_VQ_MAX; ++i)
snd->queues[i].vqueue = vqs[i];
+ snd->vqs_initialized = true;
/* Allocate events and populate the event queue */
virtqueue_disable_cb(vqs[VIRTIO_SND_VQ_EVENT]);
@@ -158,8 +169,12 @@
{
struct virtio_snd_queue *queue = virtsnd_event_queue(snd);
+ guard(spinlock_irqsave)(&queue->lock);
+ if (!queue->vqueue)
+ return;
+ snd->event_vq_enabled = true;
if (!virtqueue_enable_cb(queue->vqueue))
- virtsnd_event_notify_cb(queue->vqueue);
+ virtsnd_event_drain_locked(snd, queue->vqueue);
}
/**
@@ -172,13 +187,19 @@
{
struct virtio_snd_queue *queue = virtsnd_event_queue(snd);
struct virtio_snd_event *event;
+ bool dispatch_events;
u32 length;
+ guard(spinlock_irqsave)(&queue->lock);
+ dispatch_events = snd->event_vq_enabled;
+ snd->event_vq_enabled = false;
if (queue->vqueue) {
- guard(spinlock_irqsave)(&queue->lock);
virtqueue_disable_cb(queue->vqueue);
- while ((event = virtqueue_get_buf(queue->vqueue, &length)))
- virtsnd_event_dispatch(snd, event);
+ while ((event = virtqueue_get_buf(queue->vqueue, &length))) {
+ /* Reclaim used buffers even when failed probe cannot dispatch. */
+ if (dispatch_events)
+ virtsnd_event_dispatch(snd, event);
+ }
}
}
@@ -338,6 +359,43 @@
}
/**
+ * 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);
+ if (i == VIRTIO_SND_VQ_EVENT)
+ snd->event_vq_enabled = false;
+ /* IRQ callbacks must never see a detached ring as live. */
+ queue->vqueue = NULL;
+ spin_unlock_irqrestore(&queue->lock, flags);
+ }
+
+ if (snd->vqs_initialized) {
+ vdev->config->del_vqs(vdev);
+ snd->vqs_initialized = false;
+ }
+}
+
+/**
* virtsnd_remove() - Remove VirtIO and ALSA devices.
* @vdev: VirtIO parent device.
*
@@ -349,13 +407,14 @@
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 +442,8 @@
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);
@@ -408,10 +467,13 @@
int rc;
rc = virtsnd_find_vqs(snd);
- if (rc)
+ if (rc) {
+ virtsnd_reset_vqs(snd);
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
@@ -45,8 +45,11 @@
* struct virtio_snd - VirtIO sound card device.
* @vdev: Underlying virtio device.
* @queues: Virtqueue wrappers.
+ * @vqs_initialized: Virtqueues allocated by virtio_find_vqs().
* @card: ALSA sound card.
* @ctl_msgs: Pending control request list.
+ * @ctl_msgs_blocked: Control requests are blocked during teardown or suspend.
+ * @event_vq_enabled: Event callbacks may dispatch, protected by the event queue lock.
* @event_msgs: Device events.
* @pcm_list: VirtIO PCM device list.
* @jacks: VirtIO jacks.
@@ -62,8 +65,11 @@
struct virtio_snd {
struct virtio_device *vdev;
struct virtio_snd_queue queues[VIRTIO_SND_VQ_MAX];
+ bool vqs_initialized;
struct snd_card *card;
struct list_head ctl_msgs;
+ bool ctl_msgs_blocked;
+ bool event_vq_enabled;
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
@@ -128,6 +128,8 @@
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] 21+ messages in thread* [PATCH v25 09/16] ALSA: virtio: bound PCM transfers and retain DMA buffers
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (7 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 08/16] ALSA: virtio: Retain queued messages through device reset Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 5:34 ` sashiko-bot
2026-11-11 2:56 ` [PATCH v25 10/16] ALSA: virtio: Keep control payloads alive through DMA completion Joonho Lee
` (6 subsequent siblings)
15 siblings, 1 reply; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Validate ACK geometry, conversion bounds and queued-byte accounting
before submitting transfers. Retain the backing DMA pages until message
retirement. Check RX status and upper payload bounds while accepting
bounded short responses, including at STOP and PAUSE. Preserve the
legacy RX completion and ACK policy until the request-owned conversion,
including the legacy handling of empty PAUSE returns. The fixed-offset
layout still has short-response data gaps; request-owned capture and its
queue/accounting contract arrive together in patch 12. Non-MMU copies
use only the validated returned payload length.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
sound/virtio/virtio_pcm.h | 11 +
sound/virtio/virtio_pcm_msg.c | 306 +++++++++++++++++++++++++++++++++++------
sound/virtio/virtio_pcm_ops.c | 113 +++++++++++++++
3 files changed, 386 insertions(+), 44 deletions(-)
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.
@@ -42,6 +43,10 @@
* @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 {
@@ -68,6 +73,12 @@
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 of the fixed PCM ring slice for ordinary I/O.
* @sgs: Payload scatter-gather table.
*/
struct virtio_pcm_msg {
@@ -20,6 +24,7 @@
struct virtio_snd_pcm_xfer xfer;
struct virtio_snd_pcm_status status;
size_t length;
+ size_t data_offset;
struct scatterlist sgs[];
};
@@ -37,9 +42,8 @@
};
/**
- * 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 +51,18 @@
*/
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 +83,80 @@
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 +209,97 @@
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));
+ msg->data_offset = (size_t)period_bytes * i;
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 +315,13 @@
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;
@@ -228,8 +373,15 @@
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 +400,33 @@
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,
@@ -356,42 +535,83 @@
size_t written_bytes)
{
struct virtio_pcm_substream *vss = msg->substream;
+ bool capture_invalid = false;
/*
- * hw_ptr always indicates the buffer position of the first I/O message
- * in the virtqueue. Therefore, on each completion of an I/O message,
- * the hw_ptr value is unconditionally advanced.
+ * Completed requests can return captured data after STOP while the PCM
+ * buffer remains prepared. Once preparation ends, completions only retire
+ * queue ownership.
*/
guard(spinlock)(&vss->lock);
- /*
- * If the capture substream returned an incorrect status, then just
- * increase the hw_ptr by the message size.
- */
- if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK ||
- written_bytes <= sizeof(msg->status))
- vss->hw_ptr += msg->length;
- else
- vss->hw_ptr += written_bytes - sizeof(msg->status);
-
- if (vss->hw_ptr >= vss->buffer_bytes)
- vss->hw_ptr -= vss->buffer_bytes;
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ (!vss->prepared || vss->xfer_xrun ||
+ (vss->stopped && written_bytes <= sizeof(msg->status)))) {
+ msg->length = 0;
+ vss->msg_count--;
+ if (!vss->msg_count)
+ wake_up_all(&vss->msg_empty);
+ return;
+ }
+
+ /* Validate the returned payload before advancing the capture pointer. */
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ (written_bytes < sizeof(msg->status) ||
+ le32_to_cpu(msg->status.status) != VIRTIO_SND_S_OK ||
+ written_bytes - sizeof(msg->status) > msg->length)) {
+ dev_err_ratelimited(&vss->snd->vdev->dev,
+ "SID %u: invalid capture position, status or length\n",
+ vss->sid);
+ vss->xfer_xrun = true;
+ capture_invalid = true;
+ }
+#ifndef CONFIG_MMU
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ vss->prepared && !capture_invalid &&
+ written_bytes > sizeof(msg->status)) {
+ struct snd_pcm_runtime *runtime =
+ vss->substream ? vss->substream->runtime : NULL;
+
+ if (!runtime || !runtime->dma_area || !vss->owned_dma_area ||
+ msg->data_offset > runtime->dma_bytes ||
+ written_bytes - sizeof(msg->status) > runtime->dma_bytes - msg->data_offset ||
+ msg->data_offset > vss->owned_dma_bytes ||
+ written_bytes - sizeof(msg->status) > 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);
+ vss->xfer_xrun = true;
+ capture_invalid = true;
+ } else {
+ memcpy(runtime->dma_area + msg->data_offset,
+ vss->owned_dma_area + msg->data_offset,
+ written_bytes - sizeof(msg->status));
+ }
+ }
+#endif
+ /* Publish pointer progress only for a complete TX or valid RX request. */
+ if (!capture_invalid) {
+ vss->hw_ptr += vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ written_bytes > sizeof(msg->status) ?
+ written_bytes - sizeof(msg->status) : msg->length;
+ if (vss->hw_ptr >= vss->buffer_bytes)
+ vss->hw_ptr -= vss->buffer_bytes;
+ }
msg->length = 0;
-
- vss->xfer_xrun = false;
vss->msg_count--;
if (vss->xfer_enabled) {
- struct snd_pcm_runtime *runtime = vss->substream->runtime;
-
- runtime->delay =
- bytes_to_frames(runtime,
- le32_to_cpu(msg->status.latency_bytes));
-
+ if (!capture_invalid) {
+ struct snd_pcm_runtime *runtime = vss->substream->runtime;
+
+ runtime->delay =
+ bytes_to_frames(runtime,
+ le32_to_cpu(msg->status.latency_bytes));
+ }
schedule_work(&vss->elapsed_period);
- } else if (!vss->msg_count) {
+ }
+ 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:
*
@@ -262,10 +264,21 @@
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;
virtsnd_pcm_close_ack(substream, false);
+
+ /* 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;
@@ -608,6 +621,96 @@
int error;
};
+/* Caller holds @vss->lock and the PCM stream lock. */
+static int virtsnd_pcm_playback_ack_validate(struct virtio_pcm_substream *vss,
+ struct snd_pcm_runtime *runtime,
+ const struct snd_pcm_indirect *rec)
+{
+ snd_pcm_uframes_t appl_ptr;
+ snd_pcm_uframes_t appl_diff;
+ snd_pcm_uframes_t signed_max;
+ snd_pcm_uframes_t back;
+ u64 buffer_bits;
+ u64 appl_bits;
+ size_t appl_bytes;
+ s64 queued_bytes;
+ s64 sw_ready_total;
+ s64 total_bytes;
+ s64 int_max;
+ unsigned int hw_queue_size;
+
+ if (!runtime->control || !runtime->boundary ||
+ runtime->control->appl_ptr >= runtime->boundary ||
+ rec->appl_ptr >= runtime->boundary)
+ return -EPIPE;
+
+ /* Keep the signed frame conversion used by frames_to_bytes() in range. */
+ signed_max = (~(snd_pcm_uframes_t)0) >> 1;
+ if (runtime->boundary > signed_max ||
+ runtime->buffer_size > signed_max || !runtime->frame_bits ||
+ check_mul_overflow((u64)runtime->buffer_size,
+ (u64)runtime->frame_bits, &buffer_bits) ||
+ buffer_bits > signed_max || buffer_bits % 8 ||
+ buffer_bits / 8 != vss->buffer_bytes)
+ return -EPIPE;
+
+ /* Match the indirect helper's appl_ptr boundary-wrap calculation. */
+ appl_ptr = runtime->control->appl_ptr;
+ if (appl_ptr >= rec->appl_ptr) {
+ appl_diff = appl_ptr - rec->appl_ptr;
+ } else {
+ back = rec->appl_ptr - appl_ptr;
+ if (back <= runtime->boundary / 2)
+ return -EPIPE;
+ appl_diff = runtime->boundary - back;
+ }
+
+ if (appl_diff > runtime->buffer_size)
+ return -EPIPE;
+ /* The indirect helper advances appl_ptr even if frames_to_bytes truncates. */
+ if (!runtime->min_align || appl_diff % runtime->min_align)
+ return -EBADFD;
+ if (check_mul_overflow((u64)appl_diff,
+ (u64)runtime->frame_bits, &appl_bits) ||
+ appl_bits % 8)
+ return -EPIPE;
+
+ if (!rec->hw_buffer_size || !rec->sw_buffer_size ||
+ rec->hw_buffer_size != vss->buffer_bytes ||
+ rec->sw_buffer_size != vss->buffer_bytes || rec->hw_ready < 0 ||
+ rec->sw_ready < 0 || rec->hw_data >= rec->hw_buffer_size ||
+ rec->hw_io >= rec->hw_buffer_size ||
+ rec->sw_data >= rec->sw_buffer_size ||
+ rec->sw_io >= rec->sw_buffer_size ||
+ (unsigned int)rec->sw_ready > rec->sw_buffer_size)
+ return -EPIPE;
+
+ hw_queue_size = rec->hw_queue_size ? rec->hw_queue_size :
+ rec->hw_buffer_size;
+ if (!hw_queue_size || hw_queue_size > rec->hw_buffer_size ||
+ (unsigned int)rec->hw_ready > hw_queue_size)
+ return -EPIPE;
+
+ int_max = (int)(~0U >> 1);
+ if (hw_queue_size > int_max || appl_bits / 8 > int_max)
+ return -EPIPE;
+ appl_bytes = frames_to_bytes(runtime, (snd_pcm_sframes_t)appl_diff);
+ if (appl_bytes != (size_t)(appl_bits / 8) ||
+ check_add_overflow((s64)rec->sw_ready, (s64)appl_bytes,
+ &sw_ready_total) ||
+ sw_ready_total > int_max)
+ return -EPIPE;
+
+ /* hw_ready already excludes device completions accounted by the pointer. */
+ if (check_add_overflow((s64)rec->hw_ready, (s64)rec->sw_ready,
+ &queued_bytes) ||
+ check_add_overflow(queued_bytes, (s64)appl_bytes, &total_bytes) ||
+ total_bytes > (s64)vss->buffer_bytes)
+ return -EPIPE;
+
+ return 0;
+}
+
static void virtsnd_pcm_trans_copy(struct snd_pcm_substream *substream,
struct snd_pcm_indirect *rec, size_t bytes)
{
@@ -670,7 +773,15 @@
rc = -EPIPE;
} else {
transfer.indirect = vss->pcm_indirect;
- rc = snd_pcm_indirect_playback_transfer(substream,
+ rc = virtsnd_pcm_playback_ack_validate(vss,
+ substream->runtime,
+ &transfer.indirect);
+ if (rc == -EBADFD ||
+ (rc && substream->runtime->state ==
+ SNDRV_PCM_STATE_PAUSED))
+ return -EBADFD;
+ if (!rc)
+ rc = snd_pcm_indirect_playback_transfer(substream,
&transfer.indirect,
virtsnd_pcm_trans_copy);
if (!rc)
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH v25 09/16] ALSA: virtio: bound PCM transfers and retain DMA buffers
2026-11-11 2:56 ` [PATCH v25 09/16] ALSA: virtio: bound PCM transfers and retain DMA buffers Joonho Lee
@ 2026-11-11 5:34 ` sashiko-bot
0 siblings, 0 replies; 21+ messages in thread
From: sashiko-bot @ 2026-11-11 5:34 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 to consider:
- [Low] ALSA: virtio: missing Fixes trailer for PCM DMA page retention
and bounds fix
--
commit 119548f8da39346df59cd856937f2c76e6900cb9
Author: Joonho Lee <mynameisjune111@gmail.com>
> ALSA: virtio: bound PCM transfers and retain DMA buffers
>
> Validate ACK geometry, conversion bounds and queued-byte accounting
> before submitting transfers. Retain the backing DMA pages until message
> retirement. Check RX status and upper payload bounds while accepting
> bounded short responses, including at STOP and PAUSE. Preserve the
> legacy RX completion and ACK policy until the request-owned conversion,
> including the legacy handling of empty PAUSE returns. The fixed-offset
> layout still has short-response data gaps; request-owned capture and its
> queue/accounting contract arrive together in patch 12. Non-MMU copies
> use only the validated returned payload length.
>
> Assisted-by: LLM
> Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
[Severity: Low]
This fixes DMA page lifetime and transfer bounds handling in
virtsnd_pcm_msg_alloc() and virtsnd_pcm_msg_complete(). Should this
include:
Fixes: f40a28679e0b ("ALSA: virtio: handling control and I/O messages for the PCM device")
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261111025655.63951-1-mynameisjune111@gmail.com?part=9
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH v25 10/16] ALSA: virtio: Keep control payloads alive through DMA completion
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (8 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 09/16] ALSA: virtio: bound PCM transfers and retain DMA buffers Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 11/16] ALSA: virtio: wait through signals for PCM teardown Joonho Lee
` (5 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 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>
---
sound/virtio/virtio_ctl_msg.c | 289 +++++++++++++++++++++++++++++++----------
sound/virtio/virtio_ctl_msg.h | 24 ++-
sound/virtio/virtio_kctl.c | 121 +++++++++--------
sound/virtio/virtio_pcm_msg.c | 2
4 files changed, 300 insertions(+), 136 deletions(-)
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
@@ -688,7 +688,7 @@
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] 21+ messages in thread* [PATCH v25 11/16] ALSA: virtio: wait through signals for PCM teardown
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (9 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 10/16] ALSA: virtio: Keep control payloads alive through DMA completion Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 12/16] ALSA: virtio: use request-owned capture and serialize recovery Joonho Lee
` (4 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 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.
Keep timeout and wait results in the types returned by the kernel wait
APIs.
Fixes: 9d45e514da88 ("ALSA: virtio: handling control messages")
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
sound/virtio/virtio_ctl_msg.c | 19 ++++++++++++++++---
sound/virtio/virtio_ctl_msg.h | 3 +++
sound/virtio/virtio_pcm_ops.c | 10 +++++-----
3 files changed, 24 insertions(+), 8 deletions(-)
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
@@ -265,7 +265,7 @@
{
struct virtio_device *vdev = snd->vdev;
struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
- unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
+ unsigned long js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
struct virtio_snd_hdr *request = virtsnd_ctl_msg_request(msg);
struct virtio_snd_hdr *response = virtsnd_ctl_msg_response(msg);
unsigned int nouts = 0;
@@ -273,7 +273,7 @@
struct scatterlist *psgs[4];
bool notify = false;
unsigned long flags;
- int rc;
+ long rc;
virtsnd_ctl_msg_ref(msg);
/* This reference stays with the queue until completion or teardown. */
@@ -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.
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
@@ -20,11 +20,11 @@
* (RELEASE command in the ops->sync_stop()) and the ops->hw_free() has been
* called.
*
- * When the substream stops, the ops->sync_stop() waits until the device has
- * completed all pending messages. This wait can be interrupted either by a
- * 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.
+ * When the substream stops, ops->sync_stop() stops and releases the device
+ * as required, then waits for pending messages. A failed control request or
+ * timed-out flush can leave the device able to access messages after
+ * 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.
*
^ permalink raw reply [flat|nested] 21+ messages in thread* [PATCH v25 12/16] ALSA: virtio: use request-owned capture and serialize recovery
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (10 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 11/16] ALSA: virtio: wait through signals for PCM teardown Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 13/16] ALSA: virtio: prioritize capture period work Joonho Lee
` (3 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Receive capture into request-owned buffers and commit completed requests
in submission order. Append actual frame-aligned payloads contiguously
to the ALSA ring, preserve a valid STOP tail, and retire empty requests
without inventing data. Bound occupancy and report overflow through
XRUN.
Add explicit, default-off compatibility options for packed status
decoding and capture pause using RELEASE followed by PREPARE. The
default capture path uses request-owned buffers.
Serialize control transitions and preparation by generation, keep
payload and DMA ownership separate from the ALSA runtime, and stop
admission after uncertain control completion. Preserve linked prepare
and paused-error recovery semantics. Reject new ACK admissions after the
core buffer-access gate closes, including linked members that have not
entered their prepare callback. The PCM lock barriers wait for ACKs
admitted before gate closure. Internal RESET pointer observation remains
separately guarded.
Implement separate capture and playback RESET paths. A paused capture
RESET keeps the modulo position of the last committed sample instead of
rebasing the logical cursor independently of RX storage. This preserves
the ordinary capture reset/reopen sample sequence.
Capture DRAINING uses the progress helper for every pending
notification, including a tail crossing a period boundary and a latched
error. Running capture and playback retain their period-timer behavior.
Retain request buffers until device ownership ends. This adds temporary
memory and copies validated RX data while queue and stream locks are
held. Each period buffer is allocated separately, so page rounding can
make the allocation larger than the ALSA ring.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
sound/virtio/virtio_card.c | 58 +
sound/virtio/virtio_ctl_msg.c | 58 +
sound/virtio/virtio_ctl_msg.h | 9
sound/virtio/virtio_pcm.c | 103 ++
sound/virtio/virtio_pcm.h | 148 +++
sound/virtio/virtio_pcm_msg.c | 577 ++++++++++--
sound/virtio/virtio_pcm_ops.c | 1893 ++++++++++++++++++++++++++++++++++++-----
7 files changed, 2486 insertions(+), 360 deletions(-)
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
@@ -369,6 +369,23 @@
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->preparing = 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. */
@@ -388,7 +405,6 @@
queue->vqueue = NULL;
spin_unlock_irqrestore(&queue->lock, flags);
}
-
if (snd->vqs_initialized) {
vdev->config->del_vqs(vdev);
snd->vqs_initialized = false;
@@ -396,6 +412,30 @@
}
/**
+ * virtsnd_cancel_period_work() - Drain PCM work after control cleanup.
+ * @snd: VirtIO sound device.
+ *
+ * Must follow control message cleanup, which wakes work blocked on a PCM
+ * control request.
+ *
+ * Context: Any context that permits to sleep.
+ */
+static void virtsnd_cancel_period_work(struct virtio_snd *snd)
+{
+ unsigned int i;
+
+ 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;
+ }
+}
+
+/**
* virtsnd_remove() - Remove VirtIO and ALSA devices.
* @vdev: VirtIO parent device.
*
@@ -414,12 +454,13 @@
virtsnd_ctl_msg_cancel_all(snd);
virtsnd_reset_vqs(snd);
+ /* Wake PCM workers blocked on control replies before draining them. */
virtsnd_ctl_msg_cleanup(snd);
+ virtsnd_cancel_period_work(snd);
for (i = 0; snd->substreams && i < snd->nsubstreams; ++i) {
struct virtio_pcm_substream *vss = &snd->substreams[i];
- cancel_work_sync(&vss->elapsed_period);
virtsnd_pcm_msg_free(vss);
}
@@ -437,16 +478,14 @@
static int virtsnd_freeze(struct virtio_device *vdev)
{
struct virtio_snd *snd = vdev->priv;
- unsigned int i;
virtsnd_disable_event_vq(snd);
virtsnd_ctl_msg_cancel_all(snd);
virtsnd_reset_vqs(snd);
+ /* Wake PCM workers blocked on control replies before draining them. */
virtsnd_ctl_msg_cleanup(snd);
-
- for (i = 0; i < snd->nsubstreams; ++i)
- cancel_work_sync(&snd->substreams[i].elapsed_period);
+ virtsnd_cancel_period_work(snd);
kfree(snd->event_msgs);
snd->event_msgs = NULL;
@@ -465,6 +504,7 @@
{
struct virtio_snd *snd = vdev->priv;
int rc;
+ unsigned int i;
rc = virtsnd_find_vqs(snd);
if (rc) {
@@ -475,6 +515,12 @@
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 +310,97 @@
{
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 paused_xrun = false;
+ bool notify = false;
+ bool partial = false;
+ bool requeue = false;
+
+ /* Serialize the pointer snapshot with ALSA's pointer and ACK callbacks. */
+ guard(pcm_stream_lock_irqsave)(substream);
+ runtime = substream->runtime;
+ if (!runtime)
+ return;
+ if (!snd_pcm_running(substream) &&
+ runtime->state != SNDRV_PCM_STATE_DRAINING) {
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ paused_xrun = runtime &&
+ runtime->state == SNDRV_PCM_STATE_PAUSED &&
+ vss->xfer_xrun;
+ if (paused_xrun)
+ virtsnd_pcm_defer_paused_xrun(vss);
+ }
+ return;
+ }
+
+ if (vss->direction != SNDRV_PCM_STREAM_CAPTURE) {
+ snd_pcm_period_elapsed_under_stream_lock(substream);
+ return;
+ }
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ runtime = substream->runtime;
+ if (!runtime || !vss->runtime_active ||
+ (!vss->xfer_enabled && !vss->xfer_xrun &&
+ runtime->state != SNDRV_PCM_STATE_DRAINING))
+ 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;
+
+ /* Capture DRAINING needs pointer updates even at a period boundary. */
+ if (partial || runtime->state == SNDRV_PCM_STATE_DRAINING)
+ 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 +440,10 @@
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 +577,7 @@
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 +608,12 @@
break;
case VIRTIO_SND_EVT_PCM_XRUN:
scoped_guard(spinlock, &vss->lock) {
- if (vss->xfer_enabled)
+ if (vss->xfer_enabled ||
+ (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+ vss->prepared && !vss->stopped)) {
vss->xfer_xrun = true;
+ 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.
@@ -26,20 +45,48 @@
* @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.
+ * @period_work_quiesced: Teardown owns a work disable, protected by @lifecycle_lock.
+ * @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_submit_sequence: Next sequence assigned to a capture RX request.
+ * @capture_commit_sequence: Next capture request sequence allowed to append.
+ * @capture_quiet_sequence: Requests below this sequence were queued before a
+ * STOP or PAUSE and may complete without audio.
+ * @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 capture runtime buffer may be accessed by completions.
+ * @capture_stopping: A STOP or PAUSE is draining requests already in flight.
+ * @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: True after device PREPARE and the core pointer reset succeed;
- * protected by @lock.
- * @preparing: ACK gate through teardown and prepare's core reset;
- * protected by @lock.
+ * @prepared: Device PREPARE succeeded; protected by @lock.
+ * @preparing: ACK gate during sleeping teardown and prepare's core reset; protected by
+ * the PCM stream lock and @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.
+ * @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.
* @msgs: Allocated I/O messages.
* @nmsgs: Number of allocated I/O messages.
* @msg_count: Number of pending I/O messages in the virtqueue.
@@ -60,16 +107,41 @@
struct snd_pcm_hardware hw;
struct work_struct elapsed_period;
spinlock_t lock;
+ struct mutex lifecycle_lock;
+ bool period_work_quiesced;
+ 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_submit_sequence;
+ u64 capture_commit_sequence;
+ u64 capture_quiet_sequence;
+ u64 capture_notified_periods;
+ u64 capture_callback_snapshot;
+ bool capture_callback_snapshot_active;
+ bool runtime_active;
+ bool capture_stopping;
+ bool capture_started;
+ bool capture_free_running;
+ unsigned int capture_empty;
bool xfer_enabled;
bool xfer_xrun;
bool stopped;
bool prepared;
bool preparing;
- /* Successful PREPARE still needs RELEASE; protected by lock. */
+ /* Native control state, protected by lock. */
+ bool device_running;
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;
unsigned int nmsgs;
unsigned int msg_count;
@@ -82,6 +154,63 @@
wait_queue_head_t msg_empty;
};
+/* Caller holds the PCM stream lock and vss->lock. */
+static inline void
+virtsnd_pcm_defer_paused_xrun(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;
+
+ /* Publish the XRUN after resume, when ALSA can stop the whole group. */
+ vss->xfer_enabled = false;
+ runtime->stop_operating = true;
+}
+
+/* Give capture accounting priority over PCM callbacks that can block readers. */
+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.
@@ -112,6 +241,8 @@
extern const struct snd_pcm_ops virtsnd_pcm_ops[];
+extern bool virtsnd_capture_packed_status;
+
int virtsnd_pcm_validate(struct virtio_device *vdev);
int virtsnd_pcm_parse_cfg(struct virtio_snd *snd);
@@ -130,11 +261,16 @@
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 +3,12 @@
* virtio-snd: Virtio sound device
* Copyright (C) 2021 OpenSynergy GmbH
*/
+#include <linux/compiler.h>
+#include <linux/gcd.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"
@@ -16,15 +19,27 @@
* @xfer: Request header payload.
* @status: Response header payload.
* @length: Data length in bytes.
+ * @data: Request-owned payload for every capture request.
* @data_offset: Offset of the fixed PCM ring slice for ordinary I/O.
+ * @capture_sequence: Submission order for capture stream data.
+ * @capture_audio_bytes: Validated audio bytes returned by the device.
+ * @capture_latency_bytes: Latency returned with the capture completion.
+ * @capture_complete: Completion waits for preceding request sequences.
+ * @capture_valid: Response length and status passed protocol validation.
* @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;
size_t data_offset;
+ u64 capture_sequence;
+ size_t capture_audio_bytes;
+ u32 capture_latency_bytes;
+ bool capture_complete;
+ bool capture_valid;
struct scatterlist sgs[];
};
@@ -212,6 +227,7 @@
struct snd_pcm_runtime *runtime;
size_t buffer_bytes;
unsigned int i;
+ bool request_owned;
int rc;
if (vss->msgs || vss->nmsgs || vss->dma_pages || vss->ndma_pages)
@@ -222,10 +238,13 @@
#endif
if (!periods || !period_bytes)
return -EINVAL;
+ request_owned = vss->direction == SNDRV_PCM_STREAM_CAPTURE;
if (check_mul_overflow((size_t)periods, (size_t)period_bytes,
&buffer_bytes))
return -EOVERFLOW;
+ if (request_owned && periods < 2)
+ return -EINVAL;
if (!vss->substream || !vss->substream->runtime)
return -EINVAL;
@@ -234,14 +253,19 @@
return -EINVAL;
#ifdef CONFIG_MMU
- rc = virtsnd_pcm_dma_pages_get(vss, runtime->dma_area, buffer_bytes);
- if (rc)
- return rc;
+ if (!request_owned) {
+ 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 (!request_owned) {
+ 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);
@@ -253,32 +277,54 @@
vss->nmsgs = periods;
for (i = 0; i < periods; ++i) {
- int sg_num;
struct virtio_pcm_msg *msg;
u8 *data;
+ int sg_num;
+
+ if (request_owned) {
+ 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 (request_owned)
+ vfree(data);
rc = sg_num;
goto err_free_msgs;
}
msg = kzalloc_flex(*msg, sgs, sg_num + 2);
if (!msg) {
+ if (request_owned)
+ vfree(data);
rc = -ENOMEM;
goto err_free_msgs;
}
msg->substream = vss;
+ msg->data = request_owned ? 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));
msg->data_offset = (size_t)period_bytes * i;
virtsnd_pcm_sg_from(&msg->sgs[PCM_MSG_SG_DATA], sg_num, data,
period_bytes);
@@ -312,8 +358,14 @@
{
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);
@@ -335,15 +387,37 @@
* 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;
+ for (i = 0; vss->msgs && i < vss->nmsgs; ++i) {
+ vss->msgs[i]->capture_sequence = 0;
+ vss->msgs[i]->capture_audio_bytes = 0;
+ vss->msgs[i]->capture_latency_bytes = 0;
+ vss->msgs[i]->capture_complete = false;
+ vss->msgs[i]->capture_valid = false;
+ }
+ vss->capture_ready = 0;
+ vss->capture_copied_total = 0;
+ vss->capture_acked_total = 0;
+ vss->capture_pointer_seen_total = 0;
+ vss->capture_submit_sequence = 0;
+ vss->capture_commit_sequence = 0;
+ vss->capture_quiet_sequence = 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_stopping = false;
}
/**
@@ -373,6 +447,8 @@
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 ||
@@ -398,8 +474,8 @@
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) {
@@ -473,6 +549,365 @@
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->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->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 || msg->capture_complete)
+ continue;
+ if (vss->capture_submit_sequence == U64_MAX)
+ return -EOVERFLOW;
+
+ 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;
+ msg->capture_sequence = vss->capture_submit_sequence++;
+ msg->capture_audio_bytes = 0;
+ msg->capture_latency_bytes = 0;
+ msg->capture_valid = false;
+ 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);
+ }
+}
+
+/* Caller holds vss->lock; append only once every older request is complete. */
+static bool virtsnd_pcm_capture_commit_one_locked(
+ struct virtio_pcm_substream *vss, struct virtio_pcm_msg *msg)
+{
+ struct snd_pcm_runtime *runtime = vss->substream->runtime;
+ size_t audio_bytes = msg->capture_audio_bytes;
+ size_t next_ready = 0;
+ u64 next_copied_total;
+ bool free_running;
+ const char *invalid_reason = NULL;
+ size_t ring_ptr, first;
+ unsigned int limit;
+
+ if (!msg->capture_valid)
+ invalid_reason = "status";
+ else 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 (check_add_overflow(vss->capture_copied_total,
+ (u64)audio_bytes, &next_copied_total))
+ invalid_reason = "total_overflow";
+ else if (!audio_bytes)
+ goto empty;
+ 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)
+ goto invalid;
+
+ ring_ptr = virtsnd_pcm_ring_offset(vss->capture_copied_total,
+ vss->buffer_bytes);
+ 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,
+ msg->capture_latency_bytes);
+ return true;
+
+empty:
+ if (msg->capture_sequence >= vss->capture_quiet_sequence) {
+ limit = min_t(unsigned int, vss->nmsgs, UINT_MAX / 2) * 2;
+ if (vss->capture_started || vss->capture_empty >= limit)
+ goto invalid;
+ vss->capture_empty++;
+ }
+ runtime->delay = bytes_to_frames(runtime, msg->capture_latency_bytes);
+ return false;
+
+invalid:
+ virtsnd_pcm_capture_xrun_locked(vss);
+ dev_warn_ratelimited(&vss->snd->vdev->dev,
+ "SID %u: capture completion rejected (%s)\n",
+ vss->sid, invalid_reason ?: "empty_limit");
+ return false;
+}
+
+/* Caller holds vss->lock. */
+static bool virtsnd_pcm_capture_commit_ready_locked(
+ struct virtio_pcm_substream *vss)
+{
+ bool got_audio = false;
+ unsigned int i;
+
+ while (!vss->xfer_xrun) {
+ struct virtio_pcm_msg *next = NULL;
+
+ for (i = 0; i < vss->nmsgs; i++) {
+ struct virtio_pcm_msg *msg = vss->msgs[i];
+
+ if (msg->capture_complete &&
+ msg->capture_sequence == vss->capture_commit_sequence) {
+ next = msg;
+ break;
+ }
+ }
+ if (!next)
+ break;
+ got_audio |= virtsnd_pcm_capture_commit_one_locked(vss, next);
+ if (vss->xfer_xrun)
+ break;
+ next->capture_complete = false;
+ next->length = 0;
+ vss->capture_commit_sequence++;
+ }
+
+ if (vss->xfer_xrun) {
+ for (i = 0; i < vss->nmsgs; i++) {
+ struct virtio_pcm_msg *msg = vss->msgs[i];
+
+ if (msg->capture_complete) {
+ msg->capture_complete = false;
+ msg->length = 0;
+ }
+ }
+ }
+
+ return got_audio;
+}
+
+static void virtsnd_pcm_capture_complete(struct virtio_pcm_msg *msg,
+ size_t written_bytes)
+{
+ struct virtio_pcm_substream *vss = msg->substream;
+ struct snd_pcm_runtime *runtime;
+ size_t audio_bytes = 0;
+ u32 latency_bytes = 0;
+ size_t frame_bytes;
+ bool got_audio = false;
+ bool accept_completion;
+
+ guard(spinlock)(&vss->lock);
+ vss->msg_count--;
+ accept_completion = vss->runtime_active && vss->prepared &&
+ (!vss->stopped || vss->capture_stopping) && !vss->xfer_xrun;
+ if (accept_completion) {
+ runtime = vss->substream->runtime;
+ if (runtime && runtime->dma_area) {
+ frame_bytes = runtime->frame_bits /
+ gcd(runtime->frame_bits, 8);
+ msg->capture_valid = !virtsnd_pcm_capture_status(
+ msg, written_bytes, frame_bytes, &audio_bytes,
+ &latency_bytes);
+ msg->capture_audio_bytes = audio_bytes;
+ msg->capture_latency_bytes = latency_bytes;
+ msg->capture_complete = true;
+ got_audio = virtsnd_pcm_capture_commit_ready_locked(vss);
+ } else {
+ msg->length = 0;
+ msg->capture_complete = false;
+ }
+ } else {
+ msg->length = 0;
+ msg->capture_complete = false;
+ }
+
+ if (vss->runtime_active && vss->xfer_enabled) {
+ if (!vss->xfer_xrun && virtsnd_pcm_capture_send(vss)) {
+ dev_warn_ratelimited(&vss->snd->vdev->dev,
+ "SID %u: failed to refill capture queue\n",
+ vss->sid);
+ virtsnd_pcm_capture_xrun_locked(vss);
+ }
+ }
+ if (!vss->msg_count) {
+ wake_up_all(&vss->msg_empty);
+ }
+ if (got_audio && !vss->xfer_xrun)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+}
+
/**
* virtsnd_pcm_msg_pending_num() - Returns the number of pending I/O messages.
* @vss: VirtIO substream.
@@ -524,9 +959,9 @@
* 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.
@@ -535,80 +970,32 @@
size_t written_bytes)
{
struct virtio_pcm_substream *vss = msg->substream;
- bool capture_invalid = false;
-
- /*
- * Completed requests can return captured data after STOP while the PCM
- * buffer remains prepared. Once preparation ends, completions only retire
- * queue ownership.
- */
+ size_t completed_bytes;
+ u32 latency_bytes;
+
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ virtsnd_pcm_capture_complete(msg, written_bytes);
+ return;
+ }
+
+ /* Playback requests point directly at the ALSA ring. */
guard(spinlock)(&vss->lock);
- if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
- (!vss->prepared || vss->xfer_xrun ||
- (vss->stopped && written_bytes <= sizeof(msg->status)))) {
- msg->length = 0;
- vss->msg_count--;
- if (!vss->msg_count)
- wake_up_all(&vss->msg_empty);
- return;
- }
-
- /* Validate the returned payload before advancing the capture pointer. */
- if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
- (written_bytes < sizeof(msg->status) ||
- le32_to_cpu(msg->status.status) != VIRTIO_SND_S_OK ||
- written_bytes - sizeof(msg->status) > msg->length)) {
- dev_err_ratelimited(&vss->snd->vdev->dev,
- "SID %u: invalid capture position, status or length\n",
- vss->sid);
- vss->xfer_xrun = true;
- capture_invalid = true;
- }
-#ifndef CONFIG_MMU
- if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
- vss->prepared && !capture_invalid &&
- written_bytes > sizeof(msg->status)) {
- struct snd_pcm_runtime *runtime =
- vss->substream ? vss->substream->runtime : NULL;
-
- if (!runtime || !runtime->dma_area || !vss->owned_dma_area ||
- msg->data_offset > runtime->dma_bytes ||
- written_bytes - sizeof(msg->status) > runtime->dma_bytes - msg->data_offset ||
- msg->data_offset > vss->owned_dma_bytes ||
- written_bytes - sizeof(msg->status) > 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);
- vss->xfer_xrun = true;
- capture_invalid = true;
- } else {
- memcpy(runtime->dma_area + msg->data_offset,
- vss->owned_dma_area + msg->data_offset,
- written_bytes - sizeof(msg->status));
- }
- }
-#endif
- /* Publish pointer progress only for a complete TX or valid RX request. */
- if (!capture_invalid) {
- vss->hw_ptr += vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
- written_bytes > sizeof(msg->status) ?
- written_bytes - sizeof(msg->status) : msg->length;
- if (vss->hw_ptr >= vss->buffer_bytes)
- vss->hw_ptr -= vss->buffer_bytes;
- }
+ completed_bytes = msg->length;
+ latency_bytes = le32_to_cpu(msg->status->latency_bytes);
+ vss->hw_ptr += completed_bytes;
+ if (vss->hw_ptr >= vss->buffer_bytes)
+ vss->hw_ptr -= vss->buffer_bytes;
msg->length = 0;
+
+ /* Keep latched errors until prepare establishes a fresh epoch. */
vss->msg_count--;
if (vss->xfer_enabled) {
- if (!capture_invalid) {
- struct snd_pcm_runtime *runtime = vss->substream->runtime;
-
- runtime->delay =
- bytes_to_frames(runtime,
- le32_to_cpu(msg->status.latency_bytes));
- }
- schedule_work(&vss->elapsed_period);
+ struct snd_pcm_runtime *runtime = vss->substream->runtime;
+
+ runtime->delay = bytes_to_frames(runtime, latency_bytes);
+ virtsnd_pcm_schedule_period_elapsed(vss);
}
if (!vss->msg_count)
wake_up_all(&vss->msg_empty);
@@ -668,6 +1055,7 @@
* 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.
*
@@ -676,7 +1064,7 @@
*/
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);
@@ -694,6 +1082,7 @@
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 +3,26 @@
* virtio-snd: Virtio sound device
* Copyright (C) 2021 OpenSynergy GmbH
*/
+#include <linux/moduleparam.h>
+#include <linux/overflow.h>
+#include <linux/spinlock.h>
#include <sound/pcm_params.h>
#include "virtio_card.h"
+
+static const struct snd_pcm_ops virtsnd_pcm_capture_ops;
+
+bool virtsnd_capture_packed_status;
+module_param_named(capture_packed_status, virtsnd_capture_packed_status,
+ bool, 0444);
+MODULE_PARM_DESC(capture_packed_status,
+ "Read an explicitly opted-in packed PCM status trailer");
+
+static bool virtsnd_capture_pause_restart;
+module_param_named(capture_pause_restart, virtsnd_capture_pause_restart,
+ bool, 0444);
+MODULE_PARM_DESC(capture_pause_restart,
+ "Use release/reprepare pause compatibility instead of native pause");
/*
* I/O messages lifetime
@@ -97,48 +114,265 @@
};
static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream);
-
-/**
- * virtsnd_pcm_close_ack() - Update PCM prepare admission state.
- * @substream: Kernel ALSA substream.
- * @preparing: True while driver prepare and the core pointer reset are active.
- *
- * Context: Process context.
- */
-static void virtsnd_pcm_close_ack(struct snd_pcm_substream *substream,
- bool preparing)
-{
- struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
-
- scoped_guard(pcm_stream_lock_irqsave, substream) {
- guard(spinlock_irqsave)(&vss->lock);
- vss->prepared = false;
+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_trigger_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->preparing = preparing;
- }
-}
-
-static void virtsnd_pcm_start_failed(struct virtio_pcm_substream *vss)
-{
- scoped_guard(spinlock_irqsave, &vss->lock) {
+ vss->stopped = vss->release_required || vss->msg_count;
+ vss->xfer_xrun = true;
+ notify = vss->direction != SNDRV_PCM_STREAM_CAPTURE ||
+ vss->runtime_active;
+ }
+ 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->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;
- schedule_work(&vss->elapsed_period);
-}
-
-/* Keep completed RX data valid while RELEASE drains the device queue. */
-static void virtsnd_pcm_block_ack(struct snd_pcm_substream *substream)
-{
- struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
-
- scoped_guard(pcm_stream_lock_irqsave, substream) {
- guard(spinlock_irqsave)(&vss->lock);
- vss->preparing = true;
- vss->xfer_enabled = false;
- }
+}
+
+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 long 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->release_required = 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);
+}
+
+/* The PCM stream lock is held; defer a paused XRUN until resume commits. */
+static bool virtsnd_pcm_defer_resume_xrun(struct virtio_pcm_substream *vss,
+ u64 epoch)
+{
+ struct snd_pcm_runtime *runtime = vss->substream->runtime;
+ bool defer = false;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (!vss->resetting && vss->reset_epoch == epoch && runtime &&
+ runtime->state == SNDRV_PCM_STATE_PAUSED &&
+ vss->xfer_xrun) {
+ vss->xfer_enabled = false;
+ runtime->stop_operating = true;
+ defer = true;
+ }
+ }
+ if (defer)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+
+ return defer;
}
/**
@@ -153,23 +387,36 @@
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) {
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ vss->runtime_active = false;
+ vss->xfer_enabled = false;
+ }
+ }
+
+ /* All capture streams use request-owned receive and accounting paths. */
+ substream->ops = vss->direction == SNDRV_PCM_STREAM_CAPTURE ?
+ &virtsnd_pcm_capture_ops : &virtsnd_pcm_ops[substream->stream];
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;
}
/**
@@ -181,6 +428,15 @@
*/
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;
}
@@ -193,6 +449,7 @@
* @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.
@@ -202,7 +459,7 @@
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;
@@ -228,7 +485,7 @@
return -EINVAL;
msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_SET_PARAMS,
- GFP_KERNEL);
+ GFP_KERNEL, epoch);
if (!msg)
return -ENOMEM;
@@ -247,7 +504,14 @@
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);
}
/**
@@ -266,10 +530,10 @@
unsigned int msg_count;
size_t period_buffer_bytes;
bool stopped;
+ u64 epoch;
int rc;
- virtsnd_pcm_close_ack(substream, false);
-
+ 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),
@@ -279,6 +543,25 @@
(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->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ 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;
@@ -292,16 +575,20 @@
if (stopped) {
dev_err(&vdev->dev, "SID %u: stream release failed\n",
vss->sid);
- scoped_guard(pcm_stream_lock_irqsave, substream)
- substream->runtime->stop_operating = true;
+ substream->runtime->stop_operating = true;
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;
@@ -311,8 +598,18 @@
*/
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) {
+ guard(spinlock_irqsave)(&vss->lock);
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->suspended = false;
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE)
+ vss->runtime_active = true;
+ }
+
+ return rc;
}
/**
@@ -325,108 +622,529 @@
static int virtsnd_pcm_hw_free(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
-
- virtsnd_pcm_close_ack(substream, false);
+ 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->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ 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_device() - Prepare the PCM substream on the device.
+ * 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_device(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(pcm_stream_lock_irqsave, substream) {
+ guard(spinlock_irqsave)(&vss->lock);
+ if (vss->resetting)
+ return -ECANCELED;
+ epoch = vss->reset_epoch;
+ stopped = vss->stopped || vss->release_required || vss->msg_count;
+ vss->prepared = false;
+ vss->preparing = true;
+ }
+ if (stopped) {
+ rc = virtsnd_pcm_sync_stop_locked(substream);
+ if (rc)
+ return rc;
+ }
+ scoped_guard(pcm_stream_lock_irqsave, substream) {
+ guard(spinlock_irqsave)(&vss->lock);
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ 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;
if (stopped) {
dev_err(&vdev->dev, "SID %u: stream release failed\n",
vss->sid);
- scoped_guard(pcm_stream_lock_irqsave, substream)
- substream->runtime->stop_operating = true;
+ substream->runtime->stop_operating = true;
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);
rc = virtsnd_pcm_dev_set_params(vss, buffer_bytes, period_bytes,
- runtime->channels,
- runtime->format, runtime->rate);
- if (rc)
+ runtime->channels,
+ runtime->format, runtime->rate, epoch);
+ if (rc) {
+ if (pause_restart && rc != -ECANCELED)
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
return rc;
- }
-
- 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);
+ }
+ }
+
+ rc = virtsnd_pcm_dev_prepare(vss, epoch);
+ if (rc) {
+ if (pause_restart && rc != -ECANCELED)
+ virtsnd_pcm_pause_restart_fail(vss, false, epoch);
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->reset_epoch == epoch && !vss->resetting) {
+ vss->xfer_xrun = true;
+ vss->stopped = true;
+ }
+ }
+ return rc;
+ }
+
+ scoped_guard(pcm_stream_lock_irqsave, substream) {
+ guard(spinlock_irqsave)(&vss->lock);
+ if (epoch != vss->reset_epoch || vss->resetting)
+ return -ECANCELED;
+ vss->release_required = true;
+ vss->buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
+ vss->hw_ptr = 0;
+ 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->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ vss->capture_boundary = substream->runtime->boundary;
+ rc = virtsnd_pcm_capture_refresh_mode_locked(vss,
+ &free_running);
+ if (rc) {
+ vss->xfer_xrun = true;
+ vss->stopped = true;
+ return rc;
+ }
+ }
+ vss->prepared = true;
+ 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);
+
+ int rc;
+
+ guard(mutex)(&vss->lifecycle_lock);
+ rc = virtsnd_pcm_prepare_locked(substream);
+ if (!rc && vss->period_work_quiesced) {
+ enable_work(&vss->elapsed_period);
+ vss->period_work_quiesced = false;
+ }
+ return rc;
+}
+
+/* The core calls this after every linked member's prepare action completes. */
+static void virtsnd_pcm_prepare_complete(struct snd_pcm_substream *substream,
+ bool success)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ bool teardown_pending;
+
+ guard(spinlock_irqsave)(&vss->lock);
+ if (vss->resetting) {
+ vss->prepared = false;
+ vss->xfer_enabled = false;
+ vss->preparing = false;
+ return;
+ }
+ if (!success) {
+ teardown_pending = vss->prepared || vss->release_required ||
+ vss->msg_count || vss->device_running || vss->stopped;
+ vss->prepared = false;
+ vss->xfer_enabled = false;
+ vss->stopped = true;
+ if (teardown_pending)
+ substream->runtime->stop_operating = true;
+ }
+ vss->preparing = false;
+}
+
+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;
+ bool xrun;
+ int rc = 0;
+ u64 epoch;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting)
+ return -ECANCELED;
+ if (vss->preparing)
+ return -EBADFD;
+ epoch = vss->reset_epoch;
+ state = vss->pause_restart_state;
+ xrun = vss->xfer_xrun;
+ vss->capture_stopping = false;
+ reset_required =
+ state == VIRTSND_PCM_PAUSE_RESTART_RESET_REQUIRED ||
+ virtsnd_pcm_pause_restart_transitioning(state);
+ invalid_state =
+ (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 (xrun) {
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return -EPIPE;
+ }
+ 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 {
+ vss->release_required = true;
+ if (vss->pause_restart_state !=
+ VIRTSND_PCM_PAUSE_RESTART_PREPARED ||
+ vss->msg_count || !vss->runtime_active) {
+ rc = -EBADFD;
+ } else {
+ /* RX may complete before START responds to this PREPARE. */
+ vss->prepared = true;
+ vss->stopped = false;
+ 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->xfer_xrun) {
+ rc = -EPIPE;
+ } else if (vss->pause_restart_state !=
+ VIRTSND_PCM_PAUSE_RESTART_PREPARED ||
+ vss->msg_count || !vss->runtime_active) {
+ 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;
+ bool xrun;
+ int rc;
+ u64 epoch;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting)
+ return -ECANCELED;
+ epoch = vss->reset_epoch;
+ state = vss->pause_restart_state;
+ xrun = vss->xfer_xrun;
+ if (state != VIRTSND_PCM_PAUSE_RESTART_RELEASED) {
+ vss->xfer_enabled = false;
+ vss->stopped = true;
+ vss->capture_stopping = true;
+ vss->capture_quiet_sequence =
+ vss->capture_submit_sequence;
+ }
+ }
+ if (state == VIRTSND_PCM_PAUSE_RESTART_RELEASED) {
+ if (xrun) {
+ virtsnd_pcm_pause_restart_failed(vss, epoch);
+ return -EPIPE;
+ }
+ return 0;
+ }
+
+ 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 (suspend)
+ vss->suspended = true;
+ if (!vss->prepared && !vss->msg_count)
+ return 0;
+ vss->xfer_enabled = false;
+ vss->stopped = true;
+ vss->capture_stopping = true;
+ vss->capture_quiet_sequence = vss->capture_submit_sequence;
+ 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;
-
- scoped_guard(spinlock_irqsave, &vss->lock) {
- vss->xfer_xrun = false;
- vss->release_required = true;
- }
+ guard(spinlock_irqsave)(&vss->lock);
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->device_running = false;
return 0;
}
-/* Keep ACK closed through the core's locked pointer reset. */
-static int virtsnd_pcm_prepare(struct snd_pcm_substream *substream)
-{
- virtsnd_pcm_close_ack(substream, true);
- return virtsnd_pcm_prepare_device(substream);
-}
-
-/* Complete admission only after the linked core prepare action ends. */
-static void virtsnd_pcm_prepare_complete(
- struct snd_pcm_substream *substream, bool success)
-{
- struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
-
- scoped_guard(spinlock_irqsave, &vss->lock) {
- vss->prepared = success;
- vss->preparing = false;
- }
+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->preparing)
+ return -EBADFD;
+ 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) {
+ rc = vss->runtime_active ? virtsnd_pcm_capture_send(vss) : -EBADFD;
+ }
+ if (!rc)
+ vss->xfer_enabled = true;
+ return rc;
}
/**
- * virtsnd_pcm_trigger() - Process command for the PCM substream.
+ * virtsnd_pcm_trigger_inner() - Process command for the PCM substream.
* @substream: Kernel ALSA substream.
* @command: Substream command (SNDRV_PCM_TRIGGER_XXX).
*
@@ -434,73 +1152,304 @@
* May take and release the tx/rx queue spinlock.
* Return: 0 on success, -errno on failure.
*/
-static int virtsnd_pcm_trigger(struct snd_pcm_substream *substream, int command)
+static int virtsnd_pcm_trigger_inner(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->preparing || !vss->prepared)
- return -EBADFD;
- if (vss->stopped) {
- substream->runtime->stop_operating = true;
- return -EBADFD;
- }
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ running = vss->device_running;
if (vss->direction == SNDRV_PCM_STREAM_CAPTURE)
- rc = virtsnd_pcm_msg_send(vss, 0, vss->buffer_bytes);
- if (!rc)
- vss->xfer_enabled = true;
- }
+ vss->capture_stopping = false;
+ }
+ /* Preserve queued requests and unread RX data across native pause. */
+ rc = virtsnd_pcm_start_queue(vss, epoch);
if (rc) {
- virtsnd_pcm_start_failed(vss);
+ virtsnd_pcm_trigger_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_trigger_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_trigger_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;
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ vss->capture_stopping = true;
+ vss->capture_quiet_sequence =
+ vss->capture_submit_sequence;
+ }
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) {
+ guard(spinlock_irqsave)(&vss->lock);
+
+ if (vss->reset_epoch == epoch && !vss->resetting) {
+ vss->xfer_xrun = true;
+ substream->runtime->stop_operating = true;
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ }
+ }
+ if (rc && command == SNDRV_PCM_TRIGGER_PAUSE_PUSH) {
+ if (substream->runtime->state != SNDRV_PCM_STATE_RUNNING) {
+ /* Failed resume rollback must leave a paused queue closed. */
+ virtsnd_pcm_trigger_failed(vss, epoch);
+ } else if (virtsnd_pcm_start_queue(vss, epoch)) {
+ virtsnd_pcm_trigger_failed(vss, epoch);
+ } else if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ }
+ }
+ return rc;
default:
return -EINVAL;
}
}
+static int virtsnd_pcm_start_admission(struct virtio_pcm_substream *vss)
+{
+ int rc = 0;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting)
+ rc = -ECANCELED;
+ else if (vss->preparing)
+ rc = -EBADFD;
+ }
+
+ return rc;
+}
+
/**
- * virtsnd_pcm_sync_stop() - Synchronous PCM substream stop.
+ * virtsnd_pcm_trigger() - Defer a paused XRUN until linked resume completes.
+ * @substream: Kernel ALSA substream.
+ * @command: Substream command (SNDRV_PCM_TRIGGER_XXX).
+ *
+ * Context: Called with the PCM stream and linked-group locks held.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_pcm_trigger(struct snd_pcm_substream *substream, int command)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ u64 epoch;
+ int rc;
+
+ scoped_guard(spinlock_irqsave, &vss->lock)
+ epoch = vss->reset_epoch;
+ if (command == SNDRV_PCM_TRIGGER_START ||
+ command == SNDRV_PCM_TRIGGER_PAUSE_RELEASE) {
+ rc = virtsnd_pcm_start_admission(vss);
+ if (rc) {
+ return rc;
+ }
+ }
+
+ if (command == SNDRV_PCM_TRIGGER_PAUSE_RELEASE &&
+ virtsnd_pcm_defer_resume_xrun(vss, epoch)) {
+ return 0;
+ }
+
+ rc = virtsnd_pcm_trigger_inner(substream, command);
+ if (!rc && command == SNDRV_PCM_TRIGGER_PAUSE_PUSH)
+ substream->runtime->stop_operating = true;
+ if (command == SNDRV_PCM_TRIGGER_PAUSE_RELEASE &&
+ (rc == 0 || rc == -EPIPE) &&
+ virtsnd_pcm_defer_resume_xrun(vss, epoch))
+ rc = 0;
+
+ return rc;
+}
+
+static int
+virtsnd_pcm_pause_restart_sync_stop(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ unsigned long 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;
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ vss->capture_stopping = true;
+ vss->capture_quiet_sequence =
+ vss->capture_submit_sequence;
+ }
+ 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->release_required = 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_release_locked() - Retire the closed PCM generation.
* @substream: Kernel ALSA substream.
*
* The function can be called both from the upper level or from the driver
@@ -509,43 +1458,68 @@
* 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_release_locked(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
struct virtio_snd *snd = vss->snd;
struct virtio_snd_msg *msg;
- unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
+ unsigned long js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
bool need_release;
+ long waited;
int rc;
-
- virtsnd_pcm_block_ack(substream);
-
- scoped_guard(spinlock_irqsave, &vss->lock) {
+ u64 epoch;
+
+ lockdep_assert_held(&vss->lifecycle_lock);
+ /* Keep late RX completions from requeuing work after cancellation. */
+ if (!vss->period_work_quiesced) {
+ disable_work_sync(&vss->elapsed_period);
+ vss->period_work_quiesced = true;
+ }
+ 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);
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ vss->capture_stopping = true;
+ vss->capture_quiet_sequence =
+ vss->capture_submit_sequence;
+ }
+ }
+ /* 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) {
- scoped_guard(pcm_stream_lock_irqsave, substream)
- substream->runtime->stop_operating = true;
+ substream->runtime->stop_operating = true;
return -ENOMEM;
}
- rc = virtsnd_ctl_msg_send_sync(snd, msg);
+ rc = virtsnd_pcm_send_sync(vss, msg);
if (rc) {
- scoped_guard(pcm_stream_lock_irqsave, substream)
- substream->runtime->stop_operating = true;
+ 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;
+ }
}
/*
@@ -554,22 +1528,56 @@
* 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,
- !virtsnd_pcm_msg_pending_num(vss),
- js);
- if (rc <= 0) {
+ waited = wait_event_timeout(vss->msg_empty,
+ !virtsnd_pcm_msg_pending_num(vss),
+ js);
+ if (waited <= 0) {
dev_warn(&snd->vdev->dev, "SID %u: failed to flush I/O queue\n",
vss->sid);
- scoped_guard(pcm_stream_lock_irqsave, substream)
- substream->runtime->stop_operating = true;
-
- return !rc ? -ETIMEDOUT : rc;
- }
-
- scoped_guard(spinlock_irqsave, &vss->lock)
+ substream->runtime->stop_operating = true;
+
+ return waited ? (int)waited : -ETIMEDOUT;
+ }
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (vss->resetting || vss->reset_epoch != epoch)
+ return -ECANCELED;
+ vss->prepared = false;
vss->stopped = false;
+ }
return 0;
+}
+
+/* Close ACK admission before any sleep; prepare owns the gate through RESET. */
+static int virtsnd_pcm_sync_stop_locked(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ bool preparing;
+ int rc;
+
+ lockdep_assert_held(&vss->lifecycle_lock);
+ scoped_guard(pcm_stream_lock_irqsave, substream) {
+ guard(spinlock_irqsave)(&vss->lock);
+ preparing = vss->preparing;
+ vss->preparing = true;
+ vss->prepared = false;
+ vss->xfer_enabled = false;
+ }
+ rc = virtsnd_pcm_release_locked(substream);
+ scoped_guard(pcm_stream_lock_irqsave, substream) {
+ guard(spinlock_irqsave)(&vss->lock);
+ vss->preparing = preparing;
+ }
+ return rc;
+}
+
+static snd_pcm_uframes_t
+virtsnd_pcm_cached_pointer(struct snd_pcm_runtime *runtime)
+{
+ if (!runtime->buffer_size)
+ return 0;
+ return runtime->status->hw_ptr % runtime->buffer_size;
}
/**
@@ -584,14 +1592,49 @@
virtsnd_pcm_pb_pointer(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
-
- scoped_guard(spinlock_irqsave, &vss->lock)
- if (vss->xfer_xrun)
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ size_t hw_ptr;
+ bool paused_pointer = false;
+ bool defer_work = false;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (runtime->state == SNDRV_PCM_STATE_PAUSED) {
+ if (vss->xfer_xrun) {
+ virtsnd_pcm_defer_paused_xrun(vss);
+ defer_work = true;
+ }
+ paused_pointer = !vss->prepared || vss->preparing ||
+ vss->xfer_xrun;
+ } else if (!vss->prepared || vss->preparing || vss->xfer_xrun) {
return SNDRV_PCM_POS_XRUN;
+ }
+ if (!paused_pointer)
+ hw_ptr = vss->hw_ptr;
+ }
+ if (paused_pointer) {
+ if (defer_work)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return virtsnd_pcm_cached_pointer(runtime);
+ }
return snd_pcm_indirect_playback_pointer(substream,
- &vss->pcm_indirect,
- vss->hw_ptr);
+ &vss->pcm_indirect, hw_ptr);
+}
+
+/* Caller holds vss->lock. */
+static void virtsnd_pcm_capture_reset_pointer_locked(
+ struct virtio_pcm_substream *vss, struct snd_pcm_substream *substream,
+ u64 total)
+{
+ size_t period;
+
+ if (!vss->capture_reset_observing)
+ return;
+
+ 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;
}
/**
@@ -606,14 +1649,78 @@
virtsnd_pcm_cp_pointer(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
-
- scoped_guard(spinlock_irqsave, &vss->lock)
- if (vss->xfer_xrun)
- return SNDRV_PCM_POS_XRUN;
-
- return snd_pcm_indirect_capture_pointer(substream,
- &vss->pcm_indirect,
- vss->hw_ptr);
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ size_t hw_ptr = 0;
+ u64 total;
+ bool free_running;
+ bool xrun = false;
+ bool paused = runtime->state == SNDRV_PCM_STATE_PAUSED;
+ bool paused_pointer = false;
+ bool defer_work = false;
+
+ scoped_guard(spinlock_irqsave, &vss->lock) {
+ if (paused) {
+ if (vss->xfer_xrun) {
+ virtsnd_pcm_defer_paused_xrun(vss);
+ defer_work = true;
+ }
+ paused_pointer = !vss->runtime_active || vss->preparing ||
+ vss->suspended ||
+ (!vss->prepared &&
+ !(virtsnd_pcm_pause_restart_enabled(vss) &&
+ vss->pause_restart_state ==
+ VIRTSND_PCM_PAUSE_RESTART_RELEASED)) ||
+ vss->xfer_xrun;
+ } else {
+ if (!vss->runtime_active || vss->preparing || vss->suspended ||
+ (!vss->prepared &&
+ !(virtsnd_pcm_pause_restart_enabled(vss) &&
+ vss->pause_restart_state ==
+ VIRTSND_PCM_PAUSE_RESTART_RELEASED)))
+ return SNDRV_PCM_POS_XRUN;
+ }
+ if (!paused_pointer) {
+ 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;
+ } else {
+ vss->capture_pointer_seen_total = total;
+ hw_ptr = virtsnd_pcm_ring_offset(
+ total, vss->buffer_bytes);
+ virtsnd_pcm_capture_reset_pointer_locked(
+ vss, substream, total);
+ }
+ }
+ if (xrun) {
+ vss->xfer_xrun = true;
+ if (paused) {
+ virtsnd_pcm_defer_paused_xrun(vss);
+ paused_pointer = true;
+ defer_work = true;
+ } else {
+ return SNDRV_PCM_POS_XRUN;
+ }
+ }
+ }
+ }
+ if (paused_pointer) {
+ if (defer_work)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return virtsnd_pcm_cached_pointer(runtime);
+ }
+ return bytes_to_frames(runtime, hw_ptr);
}
struct virtsnd_pcm_transfer {
@@ -733,12 +1840,84 @@
vss->substream->runtime->stop_operating = true;
}
+/* Caller holds vss->lock; a paused ACK must not trigger linked XRUN. */
+static int virtsnd_pcm_ack_xrun_locked(struct virtio_pcm_substream *vss,
+ struct snd_pcm_runtime *runtime)
+{
+ vss->xfer_xrun = true;
+ if (runtime->state == SNDRV_PCM_STATE_PAUSED) {
+ vss->xfer_enabled = false;
+ runtime->stop_operating = true;
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return -EBADFD;
+ }
+ return -EPIPE;
+}
+
+static int virtsnd_pcm_pb_ack_locked(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 = {};
+ bool paused;
+ int rc;
+
+ scoped_guard(spinlock_irqsave, &queue->lock) {
+ guard(spinlock)(&vss->lock);
+ paused = runtime->state == SNDRV_PCM_STATE_PAUSED;
+ if (vss->preparing)
+ return -EBADFD;
+ /* A latched XRUN must not re-arm sync_stop once teardown began. */
+ if (vss->stopped && vss->xfer_xrun)
+ return -EBADFD;
+ if (vss->xfer_xrun) {
+ rc = virtsnd_pcm_ack_xrun_locked(vss, runtime);
+ } else {
+ if (!vss->prepared || vss->stopped)
+ return -EBADFD;
+ transfer.indirect = vss->pcm_indirect;
+ rc = virtsnd_pcm_playback_ack_validate(vss, runtime,
+ &transfer.indirect);
+ if (rc == -EBADFD)
+ return -EBADFD;
+ if (!rc)
+ rc = snd_pcm_indirect_playback_transfer(substream,
+ &transfer.indirect,
+ virtsnd_pcm_trans_copy);
+ }
+ if (!rc)
+ rc = transfer.error;
+ if (rc) {
+ if (paused)
+ rc = virtsnd_pcm_ack_xrun_locked(vss, runtime);
+ else
+ 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 paused ? -EBADFD : -EPIPE;
+ }
+
+ return 0;
+}
+
/* The caller holds the PCM lock, also used by DROP and state transitions. */
static int virtsnd_pcm_ack_state(struct snd_pcm_substream *substream)
{
switch (substream->runtime->state) {
case SNDRV_PCM_STATE_XRUN:
- /* The member is already XRUN; avoid stopping its linked group twice. */
+ /*
+ * pcm_lib_apply_appl_ptr() interprets -EPIPE as a new XRUN
+ * and calls __snd_pcm_xrun(), which stops the whole linked
+ * group. The stream is already XRUN; do not repeat that action.
+ */
return -EBADFD;
case SNDRV_PCM_STATE_PREPARED:
case SNDRV_PCM_STATE_RUNNING:
@@ -752,97 +1931,308 @@
}
}
+/* The PCM lock serializes ACK with prepare's accounting reset. */
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);
- struct virtsnd_pcm_transfer transfer = {};
int rc;
+ if (vss->indirect_reset_observing)
+ return 0;
rc = virtsnd_pcm_ack_state(substream);
if (rc)
return rc;
-
+ return virtsnd_pcm_pb_ack_locked(substream);
+}
+
+static int virtsnd_pcm_capture_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_uframes_t appl_diff;
+ snd_pcm_sframes_t diff;
+ size_t bytes;
+ u64 outstanding;
+ u64 next_acked_total;
+ bool free_running;
+
+ if (!vss->runtime_active || vss->preparing || !runtime || !runtime->control ||
+ !runtime->dma_area || vss->suspended)
+ return -EBADFD;
+ /* Preserve DRAINING tails only when no transfer XRUN is latched. */
+ if (vss->stopped && vss->xfer_xrun)
+ return -EBADFD;
+ if (vss->xfer_xrun)
+ return virtsnd_pcm_ack_xrun_locked(vss, runtime);
+ if (!vss->prepared &&
+ !(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->stopped && 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;
+ 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)
+ return virtsnd_pcm_ack_xrun_locked(vss, runtime);
+ appl_diff = diff;
+
+ if (!runtime->min_align) {
+ return -EBADFD;
+ }
+ if (appl_diff > runtime->buffer_size)
+ return virtsnd_pcm_ack_xrun_locked(vss, runtime);
+ if (appl_diff % runtime->min_align) {
+ return -EBADFD;
+ }
+ rc = virtsnd_pcm_capture_refresh_mode_locked(vss,
+ &free_running);
+ if (rc || !virtsnd_pcm_capture_counters_valid(vss))
+ return virtsnd_pcm_ack_xrun_locked(vss, runtime);
+
+ /* ACK includes any subperiod tail already copied to the ring. */
+ bytes = frames_to_bytes(runtime, appl_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) {
+ return virtsnd_pcm_ack_xrun_locked(vss, runtime);
+ }
+
+ vss->capture_acked_total = next_acked_total;
+ if (!free_running)
+ vss->capture_ready -= bytes;
+ vss->pcm_indirect.appl_ptr += appl_diff;
+ if (vss->pcm_indirect.appl_ptr >= runtime->boundary)
+ vss->pcm_indirect.appl_ptr -= runtime->boundary;
+ }
+
+ /* Preserve the queue -> substream lock order while refilling requests. */
scoped_guard(spinlock_irqsave, &queue->lock) {
guard(spinlock)(&vss->lock);
- if (vss->preparing || !vss->prepared)
- return -EBADFD;
- if (vss->stopped)
- return -EBADFD;
- if (vss->xfer_xrun) {
- rc = -EPIPE;
- } else {
- transfer.indirect = vss->pcm_indirect;
- rc = virtsnd_pcm_playback_ack_validate(vss,
- substream->runtime,
- &transfer.indirect);
- if (rc == -EBADFD ||
- (rc && substream->runtime->state ==
- SNDRV_PCM_STATE_PAUSED))
- return -EBADFD;
- if (!rc)
- 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);
- return -EPIPE;
- }
-
+ if (vss->runtime_active && vss->xfer_enabled &&
+ !vss->xfer_xrun) {
+ rc = virtsnd_pcm_capture_send(vss);
+ if (rc) {
+ vss->xfer_xrun = true;
+ if (runtime->state == SNDRV_PCM_STATE_PAUSED)
+ virtsnd_pcm_ack_xrun_locked(vss, runtime);
+ 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 void virtsnd_pcm_legacy_capture_copy(struct snd_pcm_substream *substream,
- struct snd_pcm_indirect *rec, size_t bytes)
+static int virtsnd_pcm_cp_ack_locked(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
-
- virtsnd_pcm_msg_send(vss, rec->sw_data, bytes);
-}
-
+ int rc = virtsnd_pcm_capture_ack(vss, substream->runtime);
+
+ if (rc == -EPIPE) {
+ guard(spinlock_irqsave)(&vss->lock);
+ virtsnd_pcm_transfer_failed(vss);
+ }
+ return rc;
+}
+
+/* Every linked member's prepare closes the ACK gate under its PCM lock. */
static int virtsnd_pcm_cp_ack(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ int rc;
+
+ /* RESET observes the pointer before returning discarded RX space. */
+ if (vss->indirect_reset_observing)
+ return 0;
+ rc = virtsnd_pcm_ack_state(substream);
+ if (rc)
+ return rc;
+ return virtsnd_pcm_cp_ack_locked(substream);
+}
+
+static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ bool teardown_pending;
+
+ 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.
+ */
+ guard(spinlock_irqsave)(&vss->lock);
+ teardown_pending = vss->prepared || vss->release_required ||
+ vss->msg_count || vss->device_running || vss->stopped;
+ 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)) {
+ /* Core may consume this marker before a later inactive teardown. */
+ if (teardown_pending)
+ substream->runtime->stop_operating = true;
+ return 0;
+ }
+ if (vss->resetting) {
+ substream->runtime->stop_operating = true;
+ return -ECANCELED;
+ }
+ }
+ return virtsnd_pcm_sync_stop_locked(substream);
+}
+
+static void virtsnd_pcm_capture_reset_error(struct virtio_pcm_substream *vss,
+ struct snd_pcm_runtime *runtime)
+{
+ size_t position = frames_to_bytes(runtime, runtime->status->hw_ptr);
+ size_t period = snd_pcm_lib_period_bytes(vss->substream);
+
+ vss->pcm_indirect.appl_ptr = runtime->status->hw_ptr;
+ vss->pcm_indirect.sw_ready = 0;
+ vss->hw_ptr = position;
+ 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_active = false;
+ if (vss->xfer_xrun) {
+ virtsnd_pcm_transfer_failed(vss);
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ }
+}
+
+/* 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;
- rc = virtsnd_pcm_ack_state(substream);
+ /* 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)
+ return rc;
+
+ guard(spinlock_irqsave)(&queue->lock);
+ guard(spinlock)(&vss->lock);
+ if (vss->resetting || vss->xfer_xrun) {
+ virtsnd_pcm_capture_reset_error(vss, runtime);
+ 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 if (runtime->state == SNDRV_PCM_STATE_PAUSED) {
+ /* Rebase paused RESET at the last sample actually committed. */
+ position = virtsnd_pcm_ring_offset(vss->capture_copied_total,
+ vss->buffer_bytes);
+ runtime->status->hw_ptr = bytes_to_frames(runtime, position);
+ vss->hw_ptr = position;
+ vss->capture_acked_total = vss->capture_copied_total;
+ vss->capture_pointer_seen_total = vss->capture_copied_total;
+ vss->capture_ready = 0;
+ period = snd_pcm_lib_period_bytes(substream);
+ vss->capture_notified_periods = period ?
+ div64_ul(vss->capture_copied_total, period) : 0;
+ } 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;
+}
+
+/* RESET can discard partial fills only after the transport returns ownership. */
+static int virtsnd_pcm_playback_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;
+ int rc;
+
+ /* The PCM lock excludes new ACK submissions through the entire reset. */
+ scoped_guard(spinlock_irqsave, &queue->lock) {
+ guard(spinlock)(&vss->lock);
+ if (vss->msg_count)
+ return -EBUSY;
+ }
+ 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->preparing || !vss->prepared)
- return -EBADFD;
- if (vss->xfer_xrun)
- return -EPIPE;
- if (vss->stopped &&
- substream->runtime->state != SNDRV_PCM_STATE_DRAINING)
- return -EBADFD;
-
- return snd_pcm_indirect_capture_transfer(substream, &vss->pcm_indirect,
- virtsnd_pcm_legacy_capture_copy);
-}
-
-/**
- * virtsnd_pcm_reset() - Reset PCM pointers.
- * @substream: Kernel ALSA substream.
- *
- * Context: PCM stream lock held.
- * Return: 0 on success, -errno on failure.
- */
-static int virtsnd_pcm_reset(struct snd_pcm_substream *substream)
-{
- return snd_pcm_lib_reset(substream);
+ position = frames_to_bytes(runtime, runtime->status->hw_ptr) %
+ vss->buffer_bytes;
+ vss->hw_ptr = position;
+ vss->pcm_indirect.hw_io = position;
+ vss->pcm_indirect.hw_data = position;
+ vss->pcm_indirect.sw_io = position;
+ vss->pcm_indirect.sw_data = position;
+ vss->pcm_indirect.hw_ready = 0;
+ vss->pcm_indirect.sw_ready = 0;
+ vss->pcm_indirect.appl_ptr = runtime->status->hw_ptr;
+ virtsnd_pcm_msg_reset(vss);
+ return 0;
}
/* PCM substream operators map. */
@@ -855,11 +2245,11 @@
.hw_free = virtsnd_pcm_hw_free,
.prepare = virtsnd_pcm_prepare,
.prepare_complete = virtsnd_pcm_prepare_complete,
- .reset = virtsnd_pcm_reset,
.trigger = virtsnd_pcm_trigger,
.sync_stop = virtsnd_pcm_sync_stop,
.pointer = virtsnd_pcm_pb_pointer,
.ack = virtsnd_pcm_pb_ack,
+ .reset = virtsnd_pcm_playback_reset,
},
{
.open = virtsnd_pcm_open,
@@ -869,10 +2259,25 @@
.hw_free = virtsnd_pcm_hw_free,
.prepare = virtsnd_pcm_prepare,
.prepare_complete = virtsnd_pcm_prepare_complete,
- .reset = virtsnd_pcm_reset,
.trigger = virtsnd_pcm_trigger,
.sync_stop = virtsnd_pcm_sync_stop,
.pointer = virtsnd_pcm_cp_pointer,
.ack = virtsnd_pcm_cp_ack,
},
};
+
+/* All capture access uses validated request-owned payloads. */
+static const struct snd_pcm_ops virtsnd_pcm_capture_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,
+ .prepare_complete = virtsnd_pcm_prepare_complete,
+ .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] 21+ messages in thread* [PATCH v25 13/16] ALSA: virtio: prioritize capture period work
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (11 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 12/16] ALSA: virtio: use request-owned capture and serialize recovery Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 14/16] docs: describe virtio-sound capture options Joonho Lee
` (2 subsequent siblings)
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Use system_highpri_wq for capture progress notifications. Capture now
always uses request-owned storage. Playback keeps the ordinary
workqueue. This preserves the priority proposal separately from recovery
and accounting. It provides no hard real-time guarantee and cannot
prevent reader overruns.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
sound/virtio/virtio_pcm.h | 3 +++
1 file changed, 3 insertions(+)
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
@@ -173,6 +173,9 @@
static inline bool
virtsnd_pcm_schedule_period_elapsed(struct virtio_pcm_substream *vss)
{
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE)
+ return queue_work(system_highpri_wq, &vss->elapsed_period);
+
return schedule_work(&vss->elapsed_period);
}
^ permalink raw reply [flat|nested] 21+ messages in thread* [PATCH v25 14/16] docs: describe virtio-sound capture options
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (12 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 13/16] ALSA: virtio: prioritize capture period work Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 6:26 ` sashiko-bot
2026-11-11 2:56 ` [PATCH v25 15/16] ALSA: virtio: reject invalid playback completions Joonho Lee
2026-11-11 2:56 ` [PATCH v25 16/16] ALSA: virtio: preserve playback progress across pause Joonho Lee
15 siblings, 1 reply; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
Document request-owned capture in the ALSA configuration guide,
including MMU vmalloc page rounding, retained allocation lifetime and
the copy into the ALSA ring.
Describe the two default-off compatibility parameters in the kernel
parameter guide. Native capture pause uses STOP and START. The optional
restart path uses STOP and RELEASE at pause, then PREPARE and START on
resume.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
Documentation/admin-guide/kernel-parameters.txt | 14 ++++++++++++++
Documentation/sound/alsa-configuration.rst | 15 +++++++++++++++
2 files changed, 29 insertions(+)
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
@@ -8344,6 +8344,20 @@
Can be used multiple times for multiple devices.
+ virtio_snd.capture_packed_status= [HW,ALSA]
+ Read an explicitly enabled packed status trailer after
+ the returned capture data. The fixed status scatterlist is
+ used by default.
+ Format: <bool>
+ Default: false.
+
+ virtio_snd.capture_pause_restart= [HW,ALSA]
+ Stop and release the stream when pausing capture. On
+ resume, send PREPARE and START. If disabled, pause uses
+ STOP and START while retaining the prepared stream.
+ Format: <bool>
+ Default: false.
+
vga= [BOOT,X86-32] Select a particular video mode
See Documentation/arch/x86/boot.rst and
Documentation/admin-guide/svga.rst.
diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sound/alsa-configuration.rst
--- a/Documentation/sound/alsa-configuration.rst
+++ b/Documentation/sound/alsa-configuration.rst
@@ -2537,6 +2537,21 @@
This module supports multiple cards.
+Module virtio-snd
+-----------------
+
+Virtio-sound capture receives data into a separate request buffer for each
+PCM period. The driver validates the responses and appends frame-aligned audio
+to the ALSA ring in request order. Valid short responses are retained. Empty
+responses are accepted only during bounded startup or for requests already in
+flight at STOP or PAUSE.
+
+On MMU systems, the request buffers are vmalloc-backed and page-rounded
+individually. Allocator rounding can make total additional memory exceed the
+ALSA ring size, especially with small periods. The request buffers remain
+allocated from hw_params until hw_free.
+Captured audio is copied from each request buffer into the ALSA ring.
+
Module snd-virtuoso
-------------------
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH v25 14/16] docs: describe virtio-sound capture options
2026-11-11 2:56 ` [PATCH v25 14/16] docs: describe virtio-sound capture options Joonho Lee
@ 2026-11-11 6:26 ` sashiko-bot
0 siblings, 0 replies; 21+ messages in thread
From: sashiko-bot @ 2026-11-11 6:26 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 to consider:
- [Low] docs: sound: virtio-snd module parameters omitted in
alsa-configuration.rst
--
commit fc63ed4859aff78c0a8bfa3a6ac071eee34558c9
Author: Joonho Lee <mynameisjune111@gmail.com>
docs: describe virtio-sound capture options
This commit documents virtio-snd capture buffer handling in
Documentation/sound/alsa-configuration.rst and adds entries for the
virtio_snd.capture_packed_status and virtio_snd.capture_pause_restart
parameters in Documentation/admin-guide/kernel-parameters.txt.
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index e75344f4e0cde..ca3fd768b4395 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -8344,6 +8344,20 @@ Kernel parameters
>
> Can be used multiple times for multiple devices.
>
> + virtio_snd.capture_packed_status= [HW,ALSA]
> + Read an explicitly enabled packed status trailer after
> + the returned capture data. The fixed status scatterlist is
> + used by default.
> + Format: <bool>
> + Default: false.
> +
> + virtio_snd.capture_pause_restart= [HW,ALSA]
> + Stop and release the stream when pausing capture. On
> + resume, send PREPARE and START. If disabled, pause uses
> + STOP and START while retaining the prepared stream.
> + Format: <bool>
> + Default: false.
> +
> vga= [BOOT,X86-32] Select a particular video mode
> See Documentation/arch/x86/boot.rst and
> Documentation/admin-guide/svga.rst.
> diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sound/alsa-configuration.rst
> index 689eccf6a5921..d40c683abc63e 100644
> --- a/Documentation/sound/alsa-configuration.rst
> +++ b/Documentation/sound/alsa-configuration.rst
> @@ -2537,6 +2537,21 @@ midi_devs
>
> This module supports multiple cards.
>
> +Module virtio-snd
> +-----------------
> +
> +Virtio-sound capture receives data into a separate request buffer for each
> +PCM period. The driver validates the responses and appends frame-aligned audio
> +to the ALSA ring in request order. Valid short responses are retained. Empty
> +responses are accepted only during bounded startup or for requests already in
> +flight at STOP or PAUSE.
> +
> +On MMU systems, the request buffers are vmalloc-backed and page-rounded
> +individually. Allocator rounding can make total additional memory exceed the
> +ALSA ring size, especially with small periods. The request buffers remain
> +allocated from hw_params until hw_free.
> +Captured audio is copied from each request buffer into the ALSA ring.
[Severity: Low]
Should capture_packed_status and capture_pause_restart also be documented
here under the "Module virtio-snd" section?
CONFIG_SND_VIRTIO is tristate and defines these options with
module_param_named() in sound/virtio/virtio_pcm_ops.c, while
Documentation/admin-guide/kernel-parameters.txt directs [HW,ALSA] users
to Documentation/sound/alsa-configuration.rst for per-driver ALSA module
parameters. This new "Module virtio-snd" subsection sits inside the
"Module parameters" section of alsa-configuration.rst, so readers looking
there for the module's parameters will not find capture_packed_status or
capture_pause_restart listed.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261111025655.63951-1-mynameisjune111@gmail.com?part=14
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH v25 15/16] ALSA: virtio: reject invalid playback completions
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (13 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 14/16] docs: describe virtio-sound capture options Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 2:56 ` [PATCH v25 16/16] ALSA: virtio: preserve playback progress across pause Joonho Lee
15 siblings, 0 replies; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
A TX completion currently advances the hardware position even when the
used length is malformed or the device reports an error. Validate the
fixed status response before publishing progress. Retire the request
once, latch XRUN and schedule error delivery while preparation is
active. Keep malformed or failed transfers out of successful playback
byte accounting.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
sound/virtio/virtio_pcm_msg.c | 11 +++++++++++
1 file changed, 11 insertions(+)
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
@@ -980,6 +980,17 @@
/* Playback requests point directly at the ALSA ring. */
guard(spinlock)(&vss->lock);
+ if (written_bytes != sizeof(*msg->status) ||
+ le32_to_cpu(msg->status->status) != VIRTIO_SND_S_OK) {
+ vss->xfer_xrun = true;
+ msg->length = 0;
+ vss->msg_count--;
+ if (!vss->msg_count)
+ wake_up_all(&vss->msg_empty);
+ if (vss->prepared && !vss->preparing)
+ virtsnd_pcm_schedule_period_elapsed(vss);
+ return;
+ }
completed_bytes = msg->length;
latency_bytes = le32_to_cpu(msg->status->latency_bytes);
vss->hw_ptr += completed_bytes;
^ permalink raw reply [flat|nested] 21+ messages in thread* [PATCH v25 16/16] ALSA: virtio: preserve playback progress across pause
2026-11-11 2:56 [PATCH v25 00/16] ALSA: virtio: serialize PCM recovery and preserve capture and playback progress Joonho Lee
` (14 preceding siblings ...)
2026-11-11 2:56 ` [PATCH v25 15/16] ALSA: virtio: reject invalid playback completions Joonho Lee
@ 2026-11-11 2:56 ` Joonho Lee
2026-11-11 7:06 ` sashiko-bot
15 siblings, 1 reply; 21+ messages in thread
From: Joonho Lee @ 2026-11-11 2:56 UTC (permalink / raw)
To: linux-sound
Cc: tiwai, perex, anton.yakovlev, mst, virtualization, linux-kernel,
corbet, skhan, rdunlap, linux-doc, Joonho Lee
TX completions can arrive after PAUSE closes transfer admission.
Preserve that progress and schedule catch-up when the stream resumes or
a rejected pause restores RUNNING. Cache device latency in stream-owned
state so a late completion does not need to dereference the ALSA
runtime. Clear both the cache and runtime delay on prepare and before
RESET observes the hardware pointer.
Use the existing indirect hw_queue_size to keep outstanding TX below one
physical ring: buffer_bytes - period_bytes. Equal modulo cursors then
mean no unobserved completion, and a non-interrupt HWSYNC cannot consume
a hidden full-ring wrap before deferred period work. Continue using the
ordinary ALSA pointer update for silence, drain, stop-threshold and
wakeup policy.
Check for pending progress or a latched transfer error again in the
period worker under the PCM stream lock. A queued notification can
outlive a paused RESET or an earlier pointer observation. Calling the
period helper without new progress after resume can turn equal cursors
into a false wrap when the core has backdated its pointer timestamp.
This reduces queued buffering by one period. With two periods, only one
period can be queued. Worst-case scheduling tolerance needs
qualification.
Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>
---
sound/virtio/virtio_pcm.c | 3 +++
sound/virtio/virtio_pcm.h | 10 ++++++++++
sound/virtio/virtio_pcm_msg.c | 8 +++-----
sound/virtio/virtio_pcm_ops.c | 19 ++++++++++++++++---
4 files changed, 32 insertions(+), 8 deletions(-)
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
@@ -338,6 +338,9 @@
}
if (vss->direction != SNDRV_PCM_STREAM_CAPTURE) {
+ /* Ignore stale work after RESET rebases the playback cursors. */
+ if (!virtsnd_pcm_playback_progress_pending(vss))
+ return;
snd_pcm_period_elapsed_under_stream_lock(substream);
return;
}
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
@@ -53,6 +53,7 @@
* substream operators, including @stopped.
* @buffer_bytes: Current buffer size in bytes.
* @hw_ptr: Substream hardware pointer value in bytes [0 ... buffer_bytes).
+ * @playback_latency_bytes: Device delay cached independently of the ALSA runtime.
* @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.
@@ -113,6 +114,7 @@
bool resetting;
size_t buffer_bytes;
size_t hw_ptr;
+ u32 playback_latency_bytes;
size_t capture_ready;
snd_pcm_uframes_t capture_boundary;
u64 capture_copied_total;
@@ -179,6 +181,14 @@
return schedule_work(&vss->elapsed_period);
}
+/* Caller holds the PCM stream lock so RESET cannot rebase these cursors. */
+static inline bool
+virtsnd_pcm_playback_progress_pending(struct virtio_pcm_substream *vss)
+{
+ guard(spinlock_irqsave)(&vss->lock);
+ return vss->xfer_xrun || vss->hw_ptr != vss->pcm_indirect.hw_io;
+}
+
/*
* ALSA may observe a subperiod tail before its period callback. Keep actual
* unread occupancy separate from pointer observations and notification state;
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
@@ -1002,12 +1002,10 @@
/* Keep latched errors until prepare establishes a fresh epoch. */
vss->msg_count--;
- if (vss->xfer_enabled) {
- struct snd_pcm_runtime *runtime = vss->substream->runtime;
-
- runtime->delay = bytes_to_frames(runtime, latency_bytes);
+ /* A queued request can outlive the ALSA runtime after hw_free. */
+ vss->playback_latency_bytes = latency_bytes;
+ if (vss->prepared && !vss->preparing)
virtsnd_pcm_schedule_period_elapsed(vss);
- }
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
@@ -770,6 +770,13 @@
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->direction == SNDRV_PCM_STREAM_PLAYBACK) {
+ /* Keep unobserved completions below one physical ring. */
+ vss->pcm_indirect.hw_queue_size = vss->buffer_bytes -
+ snd_pcm_lib_period_bytes(substream);
+ vss->playback_latency_bytes = 0;
+ substream->runtime->delay = 0;
+ }
if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
vss->capture_boundary = substream->runtime->boundary;
rc = virtsnd_pcm_capture_refresh_mode_locked(vss,
@@ -1197,7 +1204,8 @@
}
if (running) {
- if (vss->direction == SNDRV_PCM_STREAM_CAPTURE)
+ if (vss->direction == SNDRV_PCM_STREAM_CAPTURE ||
+ virtsnd_pcm_playback_progress_pending(vss))
virtsnd_pcm_schedule_period_elapsed(vss);
return 0;
}
@@ -1219,7 +1227,8 @@
return -ECANCELED;
vss->device_running = true;
}
- if (!rc && (vss->direction == SNDRV_PCM_STREAM_CAPTURE))
+ if (!rc && (vss->direction == SNDRV_PCM_STREAM_CAPTURE ||
+ virtsnd_pcm_playback_progress_pending(vss)))
virtsnd_pcm_schedule_period_elapsed(vss);
return rc;
case SNDRV_PCM_TRIGGER_SUSPEND:
@@ -1260,7 +1269,8 @@
virtsnd_pcm_trigger_failed(vss, epoch);
} else if (virtsnd_pcm_start_queue(vss, epoch)) {
virtsnd_pcm_trigger_failed(vss, epoch);
- } else if (vss->direction == SNDRV_PCM_STREAM_CAPTURE) {
+ } else if (vss->direction == SNDRV_PCM_STREAM_CAPTURE ||
+ virtsnd_pcm_playback_progress_pending(vss)) {
virtsnd_pcm_schedule_period_elapsed(vss);
}
}
@@ -1610,6 +1620,7 @@
}
if (!paused_pointer)
hw_ptr = vss->hw_ptr;
+ runtime->delay = bytes_to_frames(runtime, vss->playback_latency_bytes);
}
if (paused_pointer) {
if (defer_work)
@@ -2213,6 +2224,8 @@
guard(spinlock)(&vss->lock);
if (vss->msg_count)
return -EBUSY;
+ vss->playback_latency_bytes = 0;
+ runtime->delay = 0;
}
vss->indirect_reset_observing = true;
rc = snd_pcm_lib_reset(substream);
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH v25 16/16] ALSA: virtio: preserve playback progress across pause
2026-11-11 2:56 ` [PATCH v25 16/16] ALSA: virtio: preserve playback progress across pause Joonho Lee
@ 2026-11-11 7:06 ` sashiko-bot
0 siblings, 0 replies; 21+ messages in thread
From: sashiko-bot @ 2026-11-11 7:06 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 to consider:
- [Medium] ALSA: virtio: dropped refill in virtsnd_pcm_pb_pointer()
stalls playback
--
commit 4311dfc7324b8614c483b2c630bddb6a93007fbd
Author: Joonho Lee <mynameisjune111@gmail.com>
ALSA: virtio: preserve playback progress across pause
This commit preserves playback completion progress across pause, caches
device latency in substream state, caps indirect hw_queue_size to one period
below the buffer size, and skips period notifications when no playback
progress is pending.
> diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
> index 6d6c1bcd8601b..6c11885c55104 100644
> --- a/sound/virtio/virtio_pcm_ops.c
> +++ b/sound/virtio/virtio_pcm_ops.c
> @@ -770,6 +770,13 @@ static int virtsnd_pcm_prepare_locked(struct snd_pcm_substream *substream)
> 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->direction == SNDRV_PCM_STREAM_PLAYBACK) {
> + /* Keep unobserved completions below one physical ring. */
> + vss->pcm_indirect.hw_queue_size = vss->buffer_bytes -
> + snd_pcm_lib_period_bytes(substream);
> + vss->playback_latency_bytes = 0;
> + substream->runtime->delay = 0;
> + }
[Severity: Medium]
Can capping vss->pcm_indirect.hw_queue_size leave the held-back period in
vss->pcm_indirect.sw_ready unsubmitted if virtsnd_pcm_pb_pointer() runs while
runtime->buffer_accessing is temporarily negative?
With hw_queue_size capped at buffer_bytes - period_bytes, filling the buffer
holds the final period in vss->pcm_indirect.sw_ready until
virtsnd_pcm_pb_pointer() calls snd_pcm_indirect_playback_pointer(), which
updates hw_io and hw_ready before invoking substream->ops->ack()
(virtsnd_pcm_pb_ack()).
If a concurrent non-atomic ioctl such as SNDRV_PCM_IOCTL_RESET or
SNDRV_PCM_IOCTL_PREPARE on a running stream calls
snd_pcm_buffer_access_lock() before acquiring the PCM stream lock and being
rejected with -EBUSY, runtime->buffer_accessing is transiently -1:
sound/virtio/virtio_pcm_ops.c:virtsnd_pcm_ack_state() {
...
case SNDRV_PCM_STATE_RUNNING:
case SNDRV_PCM_STATE_PAUSED:
case SNDRV_PCM_STATE_DRAINING:
if (atomic_read(&substream->runtime->buffer_accessing) < 0)
return -EBADFD;
return 0;
...
}
snd_pcm_indirect_playback_pointer() only checks for -EPIPE and ignores
-EBADFD, so vss->pcm_indirect.hw_io advances to vss->hw_ptr without queuing
vss->pcm_indirect.sw_ready. With a two-period buffer or during
SNDRV_PCM_STATE_DRAINING, vss->msg_count reaches 0 with vss->hw_ptr equal to
vss->pcm_indirect.hw_io, virtsnd_pcm_playback_progress_pending() returns
false, and playback or drain stalls.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261111025655.63951-1-mynameisjune111@gmail.com?part=16
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