Windows - OpenVMM

OpenVMM currently has basic support for running with OpenHCL when run on Windows with WHP, with some caveats:

  1. Performance is not great due to the extra overhead of OpenVMM modeling VTLs, not the hypervisor.
  2. Not all hypercalls are implemented, only the set used by OpenHCL.
  3. Not all OpenHCL configuration and runtime management APIs are exposed / wired-up.

These are all caveats that can (and will) be overcome with additional investments into OpenVMM.

That said: running OpenHCL on OpenVMM is currently considered to be a dev-only workflow, not suitable for production use.

To get a more complete and accurate experience of what OpenHCL's production runtime characteristics and user ergonomics are like, we currently suggest running OpenHCL on Hyper-V.

Examples

Warning

These examples assume basic familiarity with the OpenVMM command line, and a willingness to deal with OpenVMM's various "rough edges" (as described in Getting Started: OpenVMM).

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 --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 -m 2GB --vmbus-com1-serial term --vmbus-com2-serial term --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 use 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.

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:

--disk file:ubuntu.img,uh --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:

--disk mem:1G,uh-nvme --vmbus-redirect