42 lines
1.4 KiB
Diff
42 lines
1.4 KiB
Diff
From 8b1dac1ad57082611419b0e2f347acd96115d25f 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 13:36:52 +0100
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Subject: [PATCH] hw/char/sclpconsole-lm: skip automatic zero-init of large
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array
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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 'process_mdb' method has a 4k byte array used for copying data
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between the guest and the chardev backend. Skip the automatic zero-init
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of this array to eliminate the performance overhead in the I/O hot
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path.
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The 'buffer' array will be selectively initialized when data is converted
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between EBCDIC and ASCII.
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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: 20250610123709.835102-15-berrange@redhat.com
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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---
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hw/char/sclpconsole-lm.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/hw/char/sclpconsole-lm.c b/hw/char/sclpconsole-lm.c
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index e9580aacba..3e40d5e434 100644
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--- a/hw/char/sclpconsole-lm.c
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+++ b/hw/char/sclpconsole-lm.c
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@@ -214,7 +214,7 @@ static int process_mdb(SCLPEvent *event, MDBO *mdbo)
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{
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int rc;
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int len;
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- uint8_t buffer[SIZE_BUFFER];
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+ QEMU_UNINITIALIZED uint8_t buffer[SIZE_BUFFER];
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len = be16_to_cpu(mdbo->length);
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len -= sizeof(mdbo->length) + sizeof(mdbo->type)
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--
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2.47.3
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