When the VM is stopped using the HMP command "stop", soon the handler will
stop reading from the vmnet interface. This causes a flood of
`VMNET_INTERFACE_PACKETS_AVAILABLE` events to arrive and puts the host CPU
at 100%. We fix this by removing the event handler from vmnet when the VM
is no longer in a running state and restore it when we return to a running
state.

Signed-off-by: Joelle van Dyne <j@getutm.app>
Signed-off-by: Jason Wang <jasowang@redhat.com>

Interaction with vmnet.framework in different modes
differs only on configuration stage, so we can create
common `send`, `receive`, etc. procedures and reuse them.

Reviewed-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Tested-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Signed-off-by: Phillip Tennen <phillip@axleos.com>
Signed-off-by: Vladislav Yaroshchuk <Vladislav.Yaroshchuk@jetbrains.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

Create separate netdevs for each vmnet operating mode:
- vmnet-host
- vmnet-shared
- vmnet-bridged

Reviewed-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Tested-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Vladislav Yaroshchuk <Vladislav.Yaroshchuk@jetbrains.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>