2k3/xp guests w/virtio-net randomly DHCP fail on boot

Host:
Debian GNU/Linux 9 with Linux 4.13.0-0.bpo.1-amd64
QEMU 2.10.1

Guest:
Windows 2003 Standard SP2 (x64)
Windows XP SP3 (i386)

QEMU command line:
http://cfp.vim-cn.com/cbdF3

Description:
After upgrading from QEMU 2.8 to 2.10.1, my Windows 2003 x64 and Windows XP guests with "virtio-net-pci" NIC would randomly fail to aquire DHCP address on boot. When it fails, cycle disable/enable the connection in Control Panel could make it connect successfully. As an immediate workaround, I switched to the RTL8139 NIC which works fine. Further investigation showed that manually reverting commit '4a3f03ba8dbf53fce36d0c1dd5d0cc0f340fe5f3' on top of 2.10.1 "fixed" the problem.

Here are the test results:
git branch 4a3f03b: 25 boots, 8 failures
git branch 39f099e: 60 boots, 0 failure
2.10.1 with revert: 194 boots, 0 failure