Feedback Request: Creating Minimal Virtio-Net for GRUB/Qemu

[Andrew Hamilton]

Hello,

I was attempting to get GRUB to be able to communicate over its
network stack for i386-pc inside Qemu to develop some additional GRUB
network protocol tests.  I wasn't able to get this working... it seems
the simulated BIOS needs to have PXE supported and enabled for GRUB to
be able to communicate in this scenario.

Based on this, I was considering writing a minimal GRUB network driver
for virtio-net to allow GRUB to communicate over the network in Qemu.
Some helpful info on virtio-net can be seen here:
https://www.redhat.com/en/blog/deep-dive-virtio-networking-and-vhost-net

The specification is here (for minimal virtio-net driver requirements):
https://docs.oasis-open.org/virtio/virtio/v1.2/cs01/virtio-v1.2-cs01.html#x1-6700004

It may require a virtio PCI driver as well, but I'm not sure about
this yet... I'd like to avoid this if possible.

Thoughts on this topic (if there is support / interest):
1. There are some -qemu targets today, so I'd expect it'd make sense
to include this new driver for those targets only (possibly a qemu
osdep?). It may be possible to expand this to cover other targets as
well as long as I can avoid any Qemu / KVM build time dependencies if
this is desirable.
2. I wasn't able to find a GPL 3.0+ virtio-net reference driver so I'd
plan to write this from scratch based on the spec
3. This may help some knowledgeable users of GRUB wishing to test
network aspects in Qemu, but my main use-case is mostly to enable
building / creating additional network tests I can run inside Qemu.


Please let me know your thoughts.

Sincerely,
Andrew Hamilton