From 372d687bc85030b8e81384010e7d35279fa4b9d3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Tue, 10 Jun 2025 13:36:55 +0100 Subject: [PATCH] hw/hyperv/syndbg: skip automatic zero-init of large array MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The 'handle_recv_msg' method has a 4k byte array used for copying data between the network socket and guest memory. Skip the automatic zero-init of this array to eliminate the performance overhead in the I/O hot path. The 'data_buf' array will be fully initialized when data is read off the network socket. Signed-off-by: Daniel P. Berrangé Reviewed-by: Stefan Hajnoczi Message-id: 20250610123709.835102-18-berrange@redhat.com Signed-off-by: Stefan Hajnoczi --- hw/hyperv/syndbg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/hyperv/syndbg.c b/hw/hyperv/syndbg.c index 065e12fb1..fd1f05d97 100644 --- a/hw/hyperv/syndbg.c +++ b/hw/hyperv/syndbg.c @@ -188,7 +188,7 @@ static uint16_t handle_recv_msg(HvSynDbg *syndbg, uint64_t outgpa, uint64_t timeout, uint32_t *retrieved_count) { uint16_t ret; - uint8_t data_buf[TARGET_PAGE_SIZE - UDP_PKT_HEADER_SIZE]; + QEMU_UNINITIALIZED uint8_t data_buf[MSG_BUFSZ]; hwaddr out_len; void *out_data; ssize_t recv_byte_count; -- 2.47.3