Thanks a lot Alex!
> All QEMU devices have two parts, a frontend (which the guest sees) and a
> backend (which is how the data gets to somewhere in the host). Some of
> the command line options in QEMU elide the details for convenience (-nic
> and -drive are examples). The -netdev device is all about configuring
> the backend of the network part for a paired -device front end. There is
> a similar setup for audio (-audiodev) although I'll defer to Gerd's
> expertise on how the two interact.
This helped me understand a bit more about how the devices work. In the source
code, I found the `virtio-net-pci.c` and `virtio-net.c` files, I think the pci device is what is visible to the guest.
So `virtio-net-pci.c` should be the front end?
For the realize function, I saw that the `virtio_net_device_realize` function initializes
the `net_conf` for the device. So I am guessing that the `virtio_snd_device_realize` function
should initialize the number of jacks and streams a device has, along with the configuration
for all these jacks and streams?
The thing is I do not understand `net` devices all that well so I get a bit confused with
what is specific to a net device and what should I actually be worried about :)
The device initalization step mentions that the jack and streams should be read and
a query should be made for the config of all jacks and streams. What should be the
default values of these configurations? I think the realize function is responsible
for setting these up.