virtio-net: add virtio-net to lambdo

[lucido-simon]

This is the main tracking issue for all the sub-issues linked to adding a virtio-net support to lambdo.

As of right now, we have identified the following tasks :

• Create a tap interface
• Create a virtio-device that uses this interface
• Allocate the necessary memory pages
• Configure the VM to let the enlightened guest know about our device
• Intercept VM-Exits that should be handled by our device

This is still an early proposal of the tasks to do. We need further exploring before truly having a grasp on what needs to be done. Please comment and discuss with us anything we missed or misunderstood, or if this does not look like a logical division of tasks.

[lucido-simon]

Hey @sameo,

We had some trouble understanding what you meant by

One virtio-mmio based networking interface (rust-vmm virtio-net)

in your issue here.

Is there supposed to be a virtio-net crate or repository somewhere in the rust-vmm organization ? We can only find C bindings for virtio-net.
However, we found an implementation (based on the foundations that rust-vmm provides) in the cloud-hypervisor project. Should we base our implementation on theirs, as a first step ?

What is your take on this ? Thanks

[sameo]

@lucido-simon @nponsard See https://github.com/rust-vmm/vm-virtio

[lucido-simon]

@lucido-simon @nponsard See https://github.com/rust-vmm/vm-virtio

There is no net device implementation, only definition for devices. You want us to code the device ourselves?

[sameo]

@lucido-simon @nponsard See https://github.com/rust-vmm/vm-virtio

There is no net device implementation, only definition for devices. You want us to code the device ourselves?

There is a bindings crate, a virtio queue implementation and a virtio device crate for the common virtio functionalities, including full virtio-mmio support. So you have to implement virtio-net on top of this, unless you want to re-implement stuff from scratch.
Ideally, you could contribute the virtio-net implementation upstream.