From cdde6ffc27517bdf069734fbc5693ce2b14edc75 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@redhat.com>
Date: Wed, 4 Jan 2012 16:28:42 +0200
Subject: [PATCH] pci: fix corrupted pci conf index register by unaligned write

Commit d0ed8076cbdc261 converted the PCI config access to the memory
API, but also inadvertantly changed it to accept unaligned writes,
and corrupt the index register in the process.  This causes a regression
booting NetBSD.

Fix by ignoring unaligned or non-dword writes.

https://bugs.launchpad.net/qemu/+bug/897771

Reported-by: Andreas Gustafsson <gson@gson.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/pci_host.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hw/pci_host.c b/hw/pci_host.c
index 44c6c207a9..804177891a 100644
--- a/hw/pci_host.c
+++ b/hw/pci_host.c
@@ -101,6 +101,9 @@ static void pci_host_config_write(void *opaque, target_phys_addr_t addr,
 
     PCI_DPRINTF("%s addr " TARGET_FMT_plx " len %d val %"PRIx64"\n",
                 __func__, addr, len, val);
+    if (addr != 0 || len != 4) {
+        return;
+    }
     s->config_reg = val;
 }
 
-- 
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