[PATCH 0/2] hw/audio/hda-codec bug fixes

[PATCH 0/2] hw/audio/hda-codec bug fixes

[Volker Rümelin]

Patch 1/2 fixes a bug that was reported and correctly diagnosed on the
QEMU devel mailing list.
https://lists.nongnu.org/archive/html/qemu-devel/2023-08/msg02539.html
There was another patch to fix this bug, but I had an objection.
https://lists.nongnu.org/archive/html/qemu-devel/2023-08/msg02925.html

Patch 2/2 corrects the sense of hda codec property mixer during
initialization. It was inverted not too long ago.

I guess Gerd is still busy with other projects. Another maintainer
probably will have to take these patches.

Volker Rümelin (2):
  hw/audio/hda-codec: fix multiplication overflow
  hw/audio/hda-codec: reenable the audio mixer

 hw/audio/hda-codec.c | 41 +++++++++++++++++++++++++++--------------
 1 file changed, 27 insertions(+), 14 deletions(-)

-- 
2.35.3

[PATCH 1/2] hw/audio/hda-codec: fix multiplication overflow

[Volker Rümelin]

After a relatively short time, there is an multiplication overflow
when multiplying (now - buft_start) with hda_bytes_per_second().
While the uptime now - buft_start only overflows after 2**63 ns
= 292.27 years, this happens hda_bytes_per_second() times faster
with the multiplication. At 44100 samples/s * 2 channels
* 2 bytes/channel = 176400 bytes/s that is 14.52 hours. After the
multiplication overflow the affected audio stream stalls.

Replace the multiplication and following division with muldiv64()
to prevent a multiplication overflow.

Fixes: 280c1e1cdb ("audio/hda: create millisecond timers that handle IO")
Reported-by: M_O_Bz <m_o_bz@163.com>
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
---
 hw/audio/hda-codec.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/hw/audio/hda-codec.c b/hw/audio/hda-codec.c
index b9ad1f4c39..f756e419bb 100644
--- a/hw/audio/hda-codec.c
+++ b/hw/audio/hda-codec.c
@@ -22,6 +22,7 @@
 #include "hw/qdev-properties.h"
 #include "intel-hda.h"
 #include "migration/vmstate.h"
+#include "qemu/host-utils.h"
 #include "qemu/module.h"
 #include "intel-hda-defs.h"
 #include "audio/audio.h"
@@ -189,9 +190,9 @@ struct HDAAudioState {
     bool     use_timer;
 };
 
-static inline int64_t hda_bytes_per_second(HDAAudioStream *st)
+static inline uint32_t hda_bytes_per_second(HDAAudioStream *st)
 {
-    return 2LL * st->as.nchannels * st->as.freq;
+    return 2 * (uint32_t)st->as.nchannels * (uint32_t)st->as.freq;
 }
 
 static inline void hda_timer_sync_adjust(HDAAudioStream *st, int64_t target_pos)
@@ -222,12 +223,18 @@ static void hda_audio_input_timer(void *opaque)
 
     int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
 
-    int64_t buft_start = st->buft_start;
+    int64_t uptime = now - st->buft_start;
     int64_t wpos = st->wpos;
     int64_t rpos = st->rpos;
+    int64_t wanted_rpos;
 
-    int64_t wanted_rpos = hda_bytes_per_second(st) * (now - buft_start)
-                          / NANOSECONDS_PER_SECOND;
+    if (uptime <= 0) {
+        /* wanted_rpos <= 0 */
+        goto out_timer;
+    }
+
+    wanted_rpos = muldiv64(uptime, hda_bytes_per_second(st),
+                           NANOSECONDS_PER_SECOND);
     wanted_rpos &= -4; /* IMPORTANT! clip to frames */
 
     if (wanted_rpos <= rpos) {
@@ -286,12 +293,18 @@ static void hda_audio_output_timer(void *opaque)
 
     int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
 
-    int64_t buft_start = st->buft_start;
+    int64_t uptime = now - st->buft_start;
     int64_t wpos = st->wpos;
     int64_t rpos = st->rpos;
+    int64_t wanted_wpos;
+
+    if (uptime <= 0) {
+        /* wanted_wpos <= 0 */
+        goto out_timer;
+    }
 
-    int64_t wanted_wpos = hda_bytes_per_second(st) * (now - buft_start)
-                          / NANOSECONDS_PER_SECOND;
+    wanted_wpos = muldiv64(uptime, hda_bytes_per_second(st),
+                           NANOSECONDS_PER_SECOND);
     wanted_wpos &= -4; /* IMPORTANT! clip to frames */
 
     if (wanted_wpos <= wpos) {
-- 
2.35.3

Re: [PATCH 1/2] hw/audio/hda-codec: fix multiplication overflow

[Marc-André Lureau]

On Sun, Nov 5, 2023 at 9:26 PM Volker Rümelin <vr_qemu@t-online.de> wrote:
>
> After a relatively short time, there is an multiplication overflow
> when multiplying (now - buft_start) with hda_bytes_per_second().
> While the uptime now - buft_start only overflows after 2**63 ns
> = 292.27 years, this happens hda_bytes_per_second() times faster
> with the multiplication. At 44100 samples/s * 2 channels
> * 2 bytes/channel = 176400 bytes/s that is 14.52 hours. After the
> multiplication overflow the affected audio stream stalls.
>
> Replace the multiplication and following division with muldiv64()
> to prevent a multiplication overflow.
>
> Fixes: 280c1e1cdb ("audio/hda: create millisecond timers that handle IO")
> Reported-by: M_O_Bz <m_o_bz@163.com>
> Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

> ---
>  hw/audio/hda-codec.c | 29 +++++++++++++++++++++--------
>  1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/hw/audio/hda-codec.c b/hw/audio/hda-codec.c
> index b9ad1f4c39..f756e419bb 100644
> --- a/hw/audio/hda-codec.c
> +++ b/hw/audio/hda-codec.c
> @@ -22,6 +22,7 @@
>  #include "hw/qdev-properties.h"
>  #include "intel-hda.h"
>  #include "migration/vmstate.h"
> +#include "qemu/host-utils.h"
>  #include "qemu/module.h"
>  #include "intel-hda-defs.h"
>  #include "audio/audio.h"
> @@ -189,9 +190,9 @@ struct HDAAudioState {
>      bool     use_timer;
>  };
>
> -static inline int64_t hda_bytes_per_second(HDAAudioStream *st)
> +static inline uint32_t hda_bytes_per_second(HDAAudioStream *st)
>  {
> -    return 2LL * st->as.nchannels * st->as.freq;
> +    return 2 * (uint32_t)st->as.nchannels * (uint32_t)st->as.freq;
>  }
>
>  static inline void hda_timer_sync_adjust(HDAAudioStream *st, int64_t target_pos)
> @@ -222,12 +223,18 @@ static void hda_audio_input_timer(void *opaque)
>
>      int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
>
> -    int64_t buft_start = st->buft_start;
> +    int64_t uptime = now - st->buft_start;
>      int64_t wpos = st->wpos;
>      int64_t rpos = st->rpos;
> +    int64_t wanted_rpos;
>
> -    int64_t wanted_rpos = hda_bytes_per_second(st) * (now - buft_start)
> -                          / NANOSECONDS_PER_SECOND;
> +    if (uptime <= 0) {
> +        /* wanted_rpos <= 0 */
> +        goto out_timer;
> +    }
> +
> +    wanted_rpos = muldiv64(uptime, hda_bytes_per_second(st),
> +                           NANOSECONDS_PER_SECOND);
>      wanted_rpos &= -4; /* IMPORTANT! clip to frames */
>
>      if (wanted_rpos <= rpos) {
> @@ -286,12 +293,18 @@ static void hda_audio_output_timer(void *opaque)
>
>      int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
>
> -    int64_t buft_start = st->buft_start;
> +    int64_t uptime = now - st->buft_start;
>      int64_t wpos = st->wpos;
>      int64_t rpos = st->rpos;
> +    int64_t wanted_wpos;
> +
> +    if (uptime <= 0) {
> +        /* wanted_wpos <= 0 */
> +        goto out_timer;
> +    }
>
> -    int64_t wanted_wpos = hda_bytes_per_second(st) * (now - buft_start)
> -                          / NANOSECONDS_PER_SECOND;
> +    wanted_wpos = muldiv64(uptime, hda_bytes_per_second(st),
> +                           NANOSECONDS_PER_SECOND);
>      wanted_wpos &= -4; /* IMPORTANT! clip to frames */
>
>      if (wanted_wpos <= wpos) {
> --
> 2.35.3
>
>


-- 
Marc-André Lureau

[PATCH 2/2] hw/audio/hda-codec: reenable the audio mixer

[Volker Rümelin]

Commit b7639b7dd0 ("hw/audio: Simplify hda audio init") inverted
the sense of hda codec property mixer during initialization.
Change the code so that mixer=on enables the hda mixer emulation
and mixer=off disables the hda mixer emulation.

With this change audio playback and recording streams don't start
muted by default.

Fixes: b7639b7dd0 ("hw/audio: Simplify hda audio init")
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
---
 hw/audio/hda-codec.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/hw/audio/hda-codec.c b/hw/audio/hda-codec.c
index f756e419bb..0bc20d49f6 100644
--- a/hw/audio/hda-codec.c
+++ b/hw/audio/hda-codec.c
@@ -868,10 +868,10 @@ static Property hda_audio_properties[] = {
 static void hda_audio_init_output(HDACodecDevice *hda, Error **errp)
 {
     HDAAudioState *a = HDA_AUDIO(hda);
-    const struct desc_codec *desc = &output_nomixemu;
+    const struct desc_codec *desc = &output_mixemu;
 
     if (!a->mixer) {
-        desc = &output_mixemu;
+        desc = &output_nomixemu;
     }
 
     hda_audio_init(hda, desc, errp);
@@ -880,10 +880,10 @@ static void hda_audio_init_output(HDACodecDevice *hda, Error **errp)
 static void hda_audio_init_duplex(HDACodecDevice *hda, Error **errp)
 {
     HDAAudioState *a = HDA_AUDIO(hda);
-    const struct desc_codec *desc = &duplex_nomixemu;
+    const struct desc_codec *desc = &duplex_mixemu;
 
     if (!a->mixer) {
-        desc = &duplex_mixemu;
+        desc = &duplex_nomixemu;
     }
 
     hda_audio_init(hda, desc, errp);
@@ -892,10 +892,10 @@ static void hda_audio_init_duplex(HDACodecDevice *hda, Error **errp)
 static void hda_audio_init_micro(HDACodecDevice *hda, Error **errp)
 {
     HDAAudioState *a = HDA_AUDIO(hda);
-    const struct desc_codec *desc = &micro_nomixemu;
+    const struct desc_codec *desc = &micro_mixemu;
 
     if (!a->mixer) {
-        desc = &micro_mixemu;
+        desc = &micro_nomixemu;
     }
 
     hda_audio_init(hda, desc, errp);
-- 
2.35.3

Re: [PATCH 2/2] hw/audio/hda-codec: reenable the audio mixer

[Marc-André Lureau]

Hi

On Sun, Nov 5, 2023 at 9:26 PM Volker Rümelin <vr_qemu@t-online.de> wrote:
>
> Commit b7639b7dd0 ("hw/audio: Simplify hda audio init") inverted
> the sense of hda codec property mixer during initialization.
> Change the code so that mixer=on enables the hda mixer emulation
> and mixer=off disables the hda mixer emulation.
>
> With this change audio playback and recording streams don't start
> muted by default.
>
> Fixes: b7639b7dd0 ("hw/audio: Simplify hda audio init")
> Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

> ---
>  hw/audio/hda-codec.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/hw/audio/hda-codec.c b/hw/audio/hda-codec.c
> index f756e419bb..0bc20d49f6 100644
> --- a/hw/audio/hda-codec.c
> +++ b/hw/audio/hda-codec.c
> @@ -868,10 +868,10 @@ static Property hda_audio_properties[] = {
>  static void hda_audio_init_output(HDACodecDevice *hda, Error **errp)
>  {
>      HDAAudioState *a = HDA_AUDIO(hda);
> -    const struct desc_codec *desc = &output_nomixemu;
> +    const struct desc_codec *desc = &output_mixemu;
>
>      if (!a->mixer) {
> -        desc = &output_mixemu;
> +        desc = &output_nomixemu;
>      }
>
>      hda_audio_init(hda, desc, errp);
> @@ -880,10 +880,10 @@ static void hda_audio_init_output(HDACodecDevice *hda, Error **errp)
>  static void hda_audio_init_duplex(HDACodecDevice *hda, Error **errp)
>  {
>      HDAAudioState *a = HDA_AUDIO(hda);
> -    const struct desc_codec *desc = &duplex_nomixemu;
> +    const struct desc_codec *desc = &duplex_mixemu;
>
>      if (!a->mixer) {
> -        desc = &duplex_mixemu;
> +        desc = &duplex_nomixemu;
>      }
>
>      hda_audio_init(hda, desc, errp);

It could be even further simplified:

    hda_audio_init(hda, a->mixer ? &output_mixemu : &output_nomixemu, errp);

> @@ -892,10 +892,10 @@ static void hda_audio_init_duplex(HDACodecDevice *hda, Error **errp)
>  static void hda_audio_init_micro(HDACodecDevice *hda, Error **errp)
>  {
>      HDAAudioState *a = HDA_AUDIO(hda);
> -    const struct desc_codec *desc = &micro_nomixemu;
> +    const struct desc_codec *desc = &micro_mixemu;
>
>      if (!a->mixer) {
> -        desc = &micro_mixemu;
> +        desc = &micro_nomixemu;
>      }
>
>      hda_audio_init(hda, desc, errp);
> --
> 2.35.3
>
>


-- 
Marc-André Lureau

Re: [PATCH 0/2] hw/audio/hda-codec bug fixes

[Michael Tokarev]

05.11.2023 20:23, Volker Rümelin :
> Patch 1/2 fixes a bug that was reported and correctly diagnosed on the
> QEMU devel mailing list.
> https://lists.nongnu.org/archive/html/qemu-devel/2023-08/msg02539.html
> There was another patch to fix this bug, but I had an objection.
> https://lists.nongnu.org/archive/html/qemu-devel/2023-08/msg02925.html
> 
> Patch 2/2 corrects the sense of hda codec property mixer during
> initialization. It was inverted not too long ago.

It looks like -stable material, is it not?

/mjt

Re: [PATCH 0/2] hw/audio/hda-codec bug fixes

[Volker Rümelin]

Am 06.11.23 um 20:54 schrieb Michael Tokarev:
> 05.11.2023 20:23, Volker Rümelin :
>> Patch 1/2 fixes a bug that was reported and correctly diagnosed on the
>> QEMU devel mailing list.
>> https://lists.nongnu.org/archive/html/qemu-devel/2023-08/msg02539.html
>> There was another patch to fix this bug, but I had an objection.
>> https://lists.nongnu.org/archive/html/qemu-devel/2023-08/msg02925.html
>>
>> Patch 2/2 corrects the sense of hda codec property mixer during
>> initialization. It was inverted not too long ago.
>
> It looks like -stable material, is it not?
>

Patch 1/2 ("hw/audio/hda-codec: fix multiplication overflow") is stable
material. Sorry, I forgot to cc qemu-stable.

With best regards,
Volker