Network devices are somewhat special, since besides being able to add them the standard way, there's a much easier one to configure them through the
-net nic parameter.
Also, please note that
-device doesn't suppress the default configuration, so it might not do what you intend.
Adding a card
-net nic on the command line adds an interface. You can select the hardware being emulated using the
qemu -net nic,model=ne2k_pci ...
Network card models
For PC emulation
|e1000||PCI||1Gb/s||Intel Gigabit Ethernet|
|pcnet||PCI||10Mb/s||AMD Ethernet Card|
|rtl8139||PCI||10/100Mb/s||Realtek Fast Ethernet|
|virtio||PCI||1Gb/s||Virtual High Performance Ethernet card (see Virtio)|
Others emulated architectures
You have to launch this command to list emulated network card
qemu-system-<arch> -net nic,model=?