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authorDaniel P. Berrangé <berrange@redhat.com>2025-06-10 13:36:57 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2025-06-12 13:40:15 -0400
commit3ccc6489dd4925ddd1f3066bd3751389169cd7aa (patch)
tree3d746a45c4b2329dd998b1c6238b03049eaf8d20 /hw/net/rtl8139.c
parent6992c886838282f36b20deee44b666bbfc573a8f (diff)
downloadfocaccia-qemu-3ccc6489dd4925ddd1f3066bd3751389169cd7aa.tar.gz
focaccia-qemu-3ccc6489dd4925ddd1f3066bd3751389169cd7aa.zip
hw/net/rtl8139: skip automatic zero-init of large array
The 'rtl8139_transmit_one' method has a 8k byte array used for
copying data between guest and host. Skip the automatic zero-init
of this array to eliminate the performance overhead in the I/O
hot path.

The 'txbuffer' will be fully initialized when reading PCI DMA
buffers.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20250610123709.835102-20-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'hw/net/rtl8139.c')
-rw-r--r--hw/net/rtl8139.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
index 15b8f7501a..654a087d80 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -1816,7 +1816,7 @@ static int rtl8139_transmit_one(RTL8139State *s, int descriptor)
 
     PCIDevice *d = PCI_DEVICE(s);
     int txsize = s->TxStatus[descriptor] & 0x1fff;
-    uint8_t txbuffer[0x2000];
+    QEMU_UNINITIALIZED uint8_t txbuffer[0x2000];
 
     DPRINTF("+++ transmit reading %d bytes from host memory at 0x%08x\n",
         txsize, s->TxAddr[descriptor]);