hw/audio/hda-codec: fix multiplication overflow
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>
Message-Id: <20231105172552.8405-1-vr_qemu@t-online.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 74e8593e7e51d6b11ae9c56a3f4e7bb714bac4ec)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
This commit is contained in:
parent
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commit
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@ -22,6 +22,7 @@
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#include "hw/qdev-properties.h"
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#include "hw/qdev-properties.h"
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#include "intel-hda.h"
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#include "intel-hda.h"
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#include "migration/vmstate.h"
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#include "migration/vmstate.h"
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#include "qemu/host-utils.h"
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#include "qemu/module.h"
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#include "qemu/module.h"
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#include "intel-hda-defs.h"
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#include "intel-hda-defs.h"
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#include "audio/audio.h"
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#include "audio/audio.h"
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@ -189,9 +190,9 @@ struct HDAAudioState {
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bool use_timer;
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bool use_timer;
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};
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};
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static inline int64_t hda_bytes_per_second(HDAAudioStream *st)
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static inline uint32_t hda_bytes_per_second(HDAAudioStream *st)
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{
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{
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return 2LL * st->as.nchannels * st->as.freq;
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return 2 * (uint32_t)st->as.nchannels * (uint32_t)st->as.freq;
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}
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}
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static inline void hda_timer_sync_adjust(HDAAudioStream *st, int64_t target_pos)
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static inline void hda_timer_sync_adjust(HDAAudioStream *st, int64_t target_pos)
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@ -222,12 +223,18 @@ static void hda_audio_input_timer(void *opaque)
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int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
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int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
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int64_t buft_start = st->buft_start;
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int64_t uptime = now - st->buft_start;
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int64_t wpos = st->wpos;
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int64_t wpos = st->wpos;
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int64_t rpos = st->rpos;
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int64_t rpos = st->rpos;
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int64_t wanted_rpos;
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int64_t wanted_rpos = hda_bytes_per_second(st) * (now - buft_start)
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if (uptime <= 0) {
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/ NANOSECONDS_PER_SECOND;
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/* wanted_rpos <= 0 */
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goto out_timer;
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}
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wanted_rpos = muldiv64(uptime, hda_bytes_per_second(st),
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NANOSECONDS_PER_SECOND);
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wanted_rpos &= -4; /* IMPORTANT! clip to frames */
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wanted_rpos &= -4; /* IMPORTANT! clip to frames */
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if (wanted_rpos <= rpos) {
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if (wanted_rpos <= rpos) {
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@ -286,12 +293,18 @@ static void hda_audio_output_timer(void *opaque)
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int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
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int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
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int64_t buft_start = st->buft_start;
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int64_t uptime = now - st->buft_start;
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int64_t wpos = st->wpos;
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int64_t wpos = st->wpos;
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int64_t rpos = st->rpos;
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int64_t rpos = st->rpos;
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int64_t wanted_wpos;
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int64_t wanted_wpos = hda_bytes_per_second(st) * (now - buft_start)
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if (uptime <= 0) {
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/ NANOSECONDS_PER_SECOND;
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/* wanted_wpos <= 0 */
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goto out_timer;
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}
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wanted_wpos = muldiv64(uptime, hda_bytes_per_second(st),
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NANOSECONDS_PER_SECOND);
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wanted_wpos &= -4; /* IMPORTANT! clip to frames */
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wanted_wpos &= -4; /* IMPORTANT! clip to frames */
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if (wanted_wpos <= wpos) {
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if (wanted_wpos <= wpos) {
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