From d2ee29691b6d6b48ba8da179e97572f5a6684a9d Mon Sep 17 00:00:00 2001
From: gubin <gubin_yewu@cmss.chinamobile.com>
Date: Mon, 18 Nov 2024 14:47:25 +0800
Subject: [PATCH] Avoid unaligned fetch in ladr_match()

cherry-pick from 6a5287ce80470bb8df95901d73ee779a64e70c3a

There is no guarantee that the PCNetState is allocated such that
csr[8] is allocated on an 8-byte boundary.  Since not all hosts are
capable of unaligned fetches the 16-bit elements need to be fetched
individually to avoid a potential fault.  Closes issue #2143

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2143
Signed-off-by: Nick Briggs <nicholas.h.briggs@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: gubin <gubin_yewu@cmss.chinamobile.com>
---
 hw/net/pcnet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/net/pcnet.c b/hw/net/pcnet.c
index a7e123e60d..7d574f487b 100644
--- a/hw/net/pcnet.c
+++ b/hw/net/pcnet.c
@@ -632,7 +632,7 @@ static inline int ladr_match(PCNetState *s, const uint8_t *buf, int size)
 {
     struct qemu_ether_header *hdr = (void *)buf;
     if ((*(hdr->ether_dhost)&0x01) &&
-        ((uint64_t *)&s->csr[8])[0] != 0LL) {
+        (s->csr[8] | s->csr[9] | s->csr[10] | s->csr[11]) != 0) {
         uint8_t ladr[8] = {
             s->csr[8] & 0xff, s->csr[8] >> 8,
             s->csr[9] & 0xff, s->csr[9] >> 8,
-- 
2.41.0.windows.1