-nic model=rocker causes qemu to abort

[Michael Tokarev]

Hi!

Just a fun case of (invalid) usage of qemu-system command line.
Someone tried -nic model=rocker, and qemu does this:

 Unexpected error in object_property_find() at 
/build/qemu/git/qom/object.c:1029:
 qemu-system-x86_64: Property '.mac' not found
 Aborted

This happens after this commit:

commit 52310c3fa7dc854dd2376ae8a518141abcdb78f3
Author: Paolo Bonzini <address@hidden>
Date:   Fri Mar 2 10:30:50 2018 +0100

    net: allow using any PCI NICs in -net or -nic


Previously rocker rightly wasn't usable as a nic model,
and after this commit it is now possible.

While I agree this is invalid usage, perhaps qemu should not
abort like this?  Maybe it should check the required property
too, before allowing this device to be a nic model?

Thanks,

/mjt