Re: [PATCH] mac80211_hwsim: add frame transmission support over virtio

[Johannes Berg <johannes@sipsolutions.net>]

On Thu, 2020-03-05 at 15:09 +0100, Marcel Holtmann wrote:
> 
> can we just make it a Kconfig option that defaults to 2, but gets set
> to 0 when virtio support is included.

We could, I guess, but I don't understand why?

I don't understand why you think there should be any relation between
virtio and the number of fake radios?

Basically, hwsim works like this:

There are a number of virtual radios (defaulting to two), which can
communicate with each other. This communication can be

1) handled inside the hwsim driver itself, "perfect" medium simulation
   without any latency etc.
2) handled over netlink with wmediumd (running inside the same kernel),
   i.e. calling out to userspace for all frame transmissions etc.

With this patch, in addition, the communication can be

3) handled over virtio to wmediumd running *outside* the qemu (untested)
   or user-mode-linux virtual machine.


So you still need virtual radios inside, and virtio doesn't *create* any
new virtual radios, it just provides the wmediumd communication
mechanism. Regardless of virtio, you can have any number of virtual
radios inside the kernel.

johannes