50 lines
1.8 KiB
Diff
50 lines
1.8 KiB
Diff
From 2553d2d26a9d0f46386bf8c37d184567e5cede6c Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
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Date: Tue, 10 Jun 2025 13:36:45 +0100
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Subject: [PATCH] hw/audio/ac97: skip automatic zero-init of large arrays
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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The 'read_audio' & 'write_audio' methods have a 4k byte array used
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for copying data between the audio backend and device. Skip the
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automatic zero-init of these arrays to eliminate the performance
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overhead in the I/O hot path.
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The 'tmpbuf' array will be fully initialized when reading data from
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the audio backend and/or device memory.
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Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
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Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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Message-id: 20250610123709.835102-8-berrange@redhat.com
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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---
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hw/audio/ac97.c | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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diff --git a/hw/audio/ac97.c b/hw/audio/ac97.c
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index 669a0463cc..eb7a847080 100644
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--- a/hw/audio/ac97.c
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+++ b/hw/audio/ac97.c
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@@ -886,7 +886,7 @@ static void nabm_writel(void *opaque, uint32_t addr, uint32_t val)
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static int write_audio(AC97LinkState *s, AC97BusMasterRegs *r,
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int max, int *stop)
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{
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- uint8_t tmpbuf[4096];
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+ QEMU_UNINITIALIZED uint8_t tmpbuf[4096];
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uint32_t addr = r->bd.addr;
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uint32_t temp = r->picb << 1;
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uint32_t written = 0;
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@@ -959,7 +959,7 @@ static void write_bup(AC97LinkState *s, int elapsed)
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static int read_audio(AC97LinkState *s, AC97BusMasterRegs *r,
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int max, int *stop)
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{
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- uint8_t tmpbuf[4096];
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+ QEMU_UNINITIALIZED uint8_t tmpbuf[4096];
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uint32_t addr = r->bd.addr;
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uint32_t temp = r->picb << 1;
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uint32_t nread = 0;
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--
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2.47.3
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