Windows - OpenVMM

OpenVMM can run OpenHCL on Windows using WHP. Compared with running OpenHCL on Hyper-V, this environment has the following differences:

Modeling VTLs in OpenVMM adds overhead compared with hypervisor-provided VTLs.
The WHP path implements the hypercalls used by OpenHCL rather than the full Hyper-V hypercall surface.
Some OpenHCL configuration and runtime management APIs are not exposed through this path.

This configuration is intended primarily for developing and validating OpenHCL. It does not reproduce every runtime or performance characteristic of Hyper-V. To evaluate behavior in a Hyper-V environment, see Running OpenHCL on Hyper-V.

Examples

Warning

These examples assume basic familiarity with the OpenVMM command line. See Running OpenVMM for an introduction.

Tip

These examples all use cargo run --, with the assumption that you are a developer building your own copy of OpenVMM locally!

To run these examples using a pre-compiled copy of OpenVMM, swap cargo run -- with /path/to/openvmm.

If you run into any issues, please refer to OpenVMM: Troubleshooting, and/or OpenHCL: Troubleshooting.

Preface: Using ohcldiag-dev

Add support for ohcldiag-dev by specifying the --vmbus-vtl2-vsock-path option at vm launch. This will create a Unix socket that the ohcldiag-dev binary can connect to by specifying the path to the unix socket. By default, the socket is created in the temp directory with path ohcldiag-dev. For example, running via powershell:

cargo run -p ohcldiag-dev -- $env:temp\ohcldiag-dev kmsg

Linux direct

Linux direct will work with an interactive console available via COM ports hosted in VTL2, relayed over VMBUS like on Hyper-V. Build a Linux direct IGVM file and launch with the following command line to enable COM0 and COM1 for VTL0:

cargo run -- --hv --vtl2 --igvm openhcl-x64.bin --com3 "term,name=VTL2 OpenHCL" -m 2GB --vmbus-com1-serial "term,name=VTL0 Linux" --vmbus-com2-serial "term,name=COM2" --vmbus-vtl2-vsock-path $env:temp\ohcldiag-dev

This will launch OpenVMM in VTL2 mode using Windows Terminal to display the output of the serial ports. You can replace term with term=<path to exe> to use your favorite shell and by default OpenVMM will use cmd.exe. A vsock window can be opened using the OpenVMM terminal on windows using v 9980 or whichever hvsock port is configured to allow consoles for OpenHCL.

Vtl2 VMBus Support

OpenHCL run under OpenVMM can act as the VMBus server to VTL0. Additionally, OpenHCL can be configured to forward offers made by OpenVMM to VTL0. For architectural background, see VMBus Relay and Device Interception.

To run OpenVMM and OpenHCL with VMBus host relay support:

 --vmbus-redirect

Assigning MANA devices to VTL2

OpenHCL can be assigned a MANA NIC to VTL2, and expose a VMBus NIC to the guest in VTL0. Expose it by adding the following:

--net uh:consomme --vmbus-redirect

Assigning SCSI devices to VTL2

You can assign a SCSI disk to VTL2 and have OpenHCL reassign it to VTL0:

--vmbus-scsi id=scsi0,vtl2 \
  --openhcl-controller id=relay0,type=scsi \
  --disk file:ubuntu.img,on=scsi0,relay=relay0 --vmbus-redirect

Assigning NVME devices to VTL2

You can assign an NVME disk to VTL2 and have OpenHCL relay it to VTL0 as a VMBus scsi device (see Storage Translation):

--nvme-pci id=nvme0,vpci,vtl2 \
  --openhcl-controller id=relay0,type=scsi \
  --disk mem:1G,on=nvme0,relay=relay0 --vmbus-redirect

The OpenVMM Guide