[OE-core] [PATCH] runqemu: support multiple NICs

[Freihofer, Adrian]

Emulating more than one network interface with runqemu is sometimes a
bit tricky, but possible. For example, this leads to an emulated device
with eth0 and eth1:

QB_NETWORK_DEVICE_prepend = " \
    -device virtio-neti-device,mac=52:54:00:12:34:03 \
"

On some emulated NIC types, Qemu and the kernel enumerate the eths in
the guest in reverse order to how the device parameters are passed to
Qemu. So in this case it is important that the additional NICs are
prepended to the -device parameter, which gets automatically added by
Qemu. Otherwise, the interface eth1 will be connected to the host, but
eth0 will be assigned the IP address 192.168.7.x, which obviously does
not work.

When booting Qemu with two NICs, but only one set of network
configuration parameters passed to the kernel, the kernel seems to
search for a configuration for all NICs. This delays the boot process
for a very long time.

This change solves the timeout problem. Tested with:
 oe-selftest --run-tests runqemu
---
 scripts/runqemu | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/runqemu b/scripts/runqemu
index dd0aa4b28f..d34f8eec25 100755
--- a/scripts/runqemu
+++ b/scripts/runqemu
@@ -1147,7 +1147,7 @@ class BaseConfig(object):
         client = gateway + 1
         if self.fstype == 'nfs':
             self.setup_nfs()
-        netconf = "192.168.7.%s::192.168.7.%s:255.255.255.0" %
(client, gateway)
+        netconf = "192.168.7.%s::192.168.7.%s:255.255.255.0::eth0" %
(client, gateway)
         logger.info("Network configuration: %s", netconf)
         self.kernel_cmdline_script += " ip=%s" % netconf
         mac = "%s%02x" % (self.mac_tap, client)