[Question] Does LinuxKernelDirect boot mode support VMBus synthetic NIC, or only GCS protocol?

[akr2dev]

I'm building a Linux VM using the Host Compute Service (HCS) LinuxKernelDirect boot mode on Windows 11 25H2. The VM boots and runs fine with SCSI storage , but I cannot get networking to function and hv_netvsc loads but never probes a device.

What I've done (host side, all confirmed working)

1. Created HCN endpoint via HcnCreateEndpoint → gets IP, MAC, switch port
2. Created HCN namespace via HcnCreateNamespace (Type: HostDefault)
3. Bound endpoint to namespace via HcnModifyNamespace
4. Get-HnsGuestNetworkService shows the VM's GNS in State 3 (running)
5. Get-HnsEndpoint shows the endpoint with VirtualMachine field set to the VM's GUID
6. hnsdiag list all confirms endpoint is attached to the switch

Comparison with WSL2

I compared HNS state between WSL2 (which has working networking) and my VM:

	WSL2	My VM
GuestNetworkService	State 3	State 3
Endpoint State	2	2
VirtualMachine field	Set	Set
Switch port attached	Yes	Yes
eth0 in guest	Works	Missing

The HNS/HCN state is identical, yet WSL2 gets a network interface and my VM doesn't.

So I want to confirm if HcsCreateComputeSystem with LinuxKernelDirect create a VMBus synthetic NIC channel, or does it rely exclusively on the GCS protocol for guest networking?

[rawahars]

For LCOWs, the NICs are attached via HCS call and then GCS protocol is used to configure the NICs within the guest.
Reference- https://github.com/microsoft/hcsshim/blob/main/internal/uvm/network.go