net/socket: skip automatic zero-init of large array

The 'net_socket_send' method has a 68k 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 'buf1' array will be fully initialized when reading data off
the network socket.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Message-id: 20250610123709.835102-31-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

diff --git a/net/socket.c b/net/socket.c
index 8e3702e1f3a87f4a24e34df400b71e02a4461b4b..784dda686f52077446f47778d0ffca8a43223235 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -157,7 +157,7 @@ static void net_socket_send(void *opaque)
     NetSocketState *s = opaque;
     int size;
     int ret;
-    uint8_t buf1[NET_BUFSIZE];
+    QEMU_UNINITIALIZED uint8_t buf1[NET_BUFSIZE];
     const uint8_t *buf;
 
     size = recv(s->fd, buf1, sizeof(buf1), 0);