From: Daniel P. Berrangé Date: Tue, 10 Jun 2025 12:36:58 +0000 (+0100) Subject: hw/net/tulip: skip automatic zero-init of large array X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e1afd5ee6eb2954f4baf3c97820e4aaf7de97d2a;p=thirdparty%2Fqemu.git hw/net/tulip: skip automatic zero-init of large array The 'tulip_setup_frame' method has a 4k byte array used for copynig DMA data from the device. Skip the automatic zero-init of this array to eliminate the performance overhead in the I/O hot path. The 'buf' array will be fully initialized when reading data from the device. Signed-off-by: Daniel P. Berrangé Reviewed-by: Stefan Hajnoczi Message-id: 20250610123709.835102-21-berrange@redhat.com Signed-off-by: Stefan Hajnoczi --- diff --git a/hw/net/tulip.c b/hw/net/tulip.c index 63fe513458..319af906c8 100644 --- a/hw/net/tulip.c +++ b/hw/net/tulip.c @@ -629,7 +629,7 @@ static void tulip_setup_filter_addr(TULIPState *s, uint8_t *buf, int n) static void tulip_setup_frame(TULIPState *s, struct tulip_descriptor *desc) { - uint8_t buf[4096]; + QEMU_UNINITIALIZED uint8_t buf[4096]; int len = (desc->control >> TDES1_BUF1_SIZE_SHIFT) & TDES1_BUF1_SIZE_MASK; int i;