net: Add a new convenience option "--nic" to configure default/on-board NICs

The legacy "-net" option can be quite confusing for the users since most
people do not expect to get a "vlan" hub between their emulated guest
hardware and the host backend. But so far, we are also not able to get
rid of "-net" completely, since it is the only way to configure on-board
NICs that can not be instantiated via "-device" yet. It's also a little
bit shorter to type "-net nic -net tap" instead of "-device xyz,netdev=n1
-netdev tap,id=n1".

So what we need is a new convenience option that is shorter to type than
the full -device + -netdev stuff, and which can be used to configure the
on-board NICs that can not be handled via -device yet. Thus this patch now
provides such a new option "--nic": It adds an entry in the nd_table to
configure a on-board / default NIC, creates a host backend and connects
the two directly, without a confusing "vlan" hub inbetween.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/vl.c b/vl.c
index 1931621426..d15985ddac 100644
--- a/vl.c
+++ b/vl.c
@@ -3091,6 +3091,7 @@ int main(int argc, char **argv, char **envp)
     qemu_add_opts(&qemu_chardev_opts);
     qemu_add_opts(&qemu_device_opts);
     qemu_add_opts(&qemu_netdev_opts);
+    qemu_add_opts(&qemu_nic_opts);
     qemu_add_opts(&qemu_net_opts);
     qemu_add_opts(&qemu_rtc_opts);
     qemu_add_opts(&qemu_global_opts);
@@ -3311,6 +3312,12 @@ int main(int argc, char **argv, char **envp)
                     exit(1);
                 }
                 break;
+            case QEMU_OPTION_nic:
+                default_net = 0;
+                if (net_client_parse(qemu_find_opts("nic"), optarg) == -1) {
+                    exit(1);
+                }
+                break;
             case QEMU_OPTION_net:
                 default_net = 0;
                 if (net_client_parse(qemu_find_opts("net"), optarg) == -1) {