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hw/char/sclpconsole-lm: skip automatic zero-init of large array

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The 'process_mdb' method has a 4k byte array used for copying data
between the guest and the chardev backend. Skip the automatic zero-init
of this array to eliminate the performance overhead in the I/O hot
path.

The 'buffer' array will be selectively initialized when data is converted
between EBCDIC and ASCII.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20250610123709.835102-15-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Daniel P. Berrangé 2025-06-10 13:36:52 +01:00 • committed by Stefan Hajnoczi
parent bb71d9fe14
commit 8b1dac1ad5
1 changed files with 1 additions and 1 deletions
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2
hw/char/sclpconsole-lm.c
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@ -214,7 +214,7 @@ static int process_mdb(SCLPEvent *event, MDBO *mdbo)
{
int rc;
int len;
uint8_t buffer[SIZE_BUFFER];
QEMU_UNINITIALIZED uint8_t buffer[SIZE_BUFFER];
len = be16_to_cpu(mdbo->length);
len -= sizeof(mdbo->length) + sizeof(mdbo->type)