qdev: Catch attempt to attach more than one device to a netdev
Guest device and host netdev are peers, i.e. it's a 1:1 relation.
However, we fail to enforce that:
$ qemu -nodefaults --nographic -netdev user,id=net0 -device e1000,netdev=net0 -device virtio-net-pci,netdev=net0 -monitor stdio
QEMU 0.12.50 monitor - type 'help' for more information
(qemu) info network
Devices not on any VLAN:
net0: net=10.0.2.0, restricted=n peer=virtio-net-pci.0
e1000.0: model=e1000,macaddr=52:54:00:12:34:56 peer=net0
virtio-net-pci.0: model=virtio-net-pci,macaddr=52:54:00:12:34:57 peer=net0
It's all downhill from there.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
index 438eaea..24671af 100644
--- a/hw/qdev-properties.c
+++ b/hw/qdev-properties.c
@@ -341,6 +341,9 @@
*ptr = qemu_find_netdev(str);
if (*ptr == NULL)
return -ENOENT;
+ if ((*ptr)->peer) {
+ return -EEXIST;
+ }
return 0;
}
@@ -557,6 +560,10 @@
ret = prop->info->parse(dev, prop, value);
if (ret < 0) {
switch (ret) {
+ case -EEXIST:
+ fprintf(stderr, "property \"%s.%s\": \"%s\" is already in use\n",
+ dev->info->name, name, value);
+ break;
default:
case -EINVAL:
fprintf(stderr, "property \"%s.%s\": failed to parse \"%s\"\n",