Interactive console: Add command vtl2-settings to show/modify VTL2 settings

[alandau]

The command shows the current VTL2 settings and allows modifying them to add/remove SCSI disks exposed to VTL0 that are backed by NVMe namespaces or SCSI LUNs in VTL2.

Examples:

 # Run OpenVMM providing an NVMe namespace to VTL2, which exposes it as
 # a SCSI disk to VTL0. Use `--disk mem:1024,uh` instead to provide a SCSI LUN.
C:\openvmm>openvmm.exe -m 4GB -p 4 --vmbus-com1-serial term --hv --vtl2 --igvm "openhcl-x64-test-linux-direct.bin" --vtl2-vsock-path "C:\openvmm\uhdiag.sock" --com3 term --no-alias-map --vmbus-redirect --disk mem:1024,uh-nvme

 # Show current VTL2 settings
openvmm> vtl2-settings show
Vtl2Settings {
    namespace_settings: [],
    version: V1,
    fixed: Some(
        Vtl2SettingsFixed {
            scsi_sub_channels: None,
            io_ring_size: None,
            max_bounce_buffer_pages: None,
        },
    ),
    dynamic: Some(
        Vtl2SettingsDynamic {
            storage_controllers: [
                StorageController {
                    instance_id: "e1c5bd94-d0d6-41d4-a2b0-88095a16ded7",
                    protocol: Scsi,
                    luns: [
                        Lun {
                            channel: None,
                            location: 0,
                            device_id: "7acac475-b4f2-4631-926c-3978ab3429fc",
                            vendor_id: "OpenVMM",
                            product_id: "Disk",
                            product_revision_level: "1.0",
                            serial_number: "0",
                            model_number: "1",
                            medium_rotation_rate: None,
                            physical_sector_size: None,
                            fua: None,
                            write_cache: None,
                            odx: None,
                            disable_thin_provisioning: None,
                            max_transfer_length: None,
                            physical_devices: Some(
                                PhysicalDevices {
                                    r#type: Single,
                                    device: Some(
                                        PhysicalDevice {
                                            device_type: Nvme,
                                            device_path: "f9b90f6f-b129-4596-8171-a23481b8f718",
                                            sub_device_path: 1,
                                        },
                                    ),
                                    devices: [],
                                },
                            ),
                            is_dvd: false,
                            chunk_size_in_kb: 0,
                            scsi_disk_size_in_bytes: None,
                            ntfs_guid: None,
                            total_logic_size_in_kb: 0,
                            device_type: None,
                            device_path: None,
                            sub_device_path: None,
                        },
                    ],
                    io_queue_depth: None,
                },
            ],
            nic_devices: [],
        },
    ),
}

 # Remove disk from the guest
openvmm> vtl2-settings rm-scsi-disk --lun 0
Removed VTL0 SCSI disk: controller=e1c5bd94-d0d6-41d4-a2b0-88095a16ded7, lun=0

 # Add it back. Or use --backing-scsi-lun if the backing is SCSI.
openvmm> vtl2-settings add-scsi-disk --lun 0 --backing-nvme-nsid 1
Added VTL0 SCSI disk: controller=e1c5bd94-d0d6-41d4-a2b0-88095a16ded7, lun=0, backing=nvme_nsid=1

[Copilot]

Pull request overview

Adds an interactive console command (vtl2-settings) to inspect and modify OpenHCL VTL2 settings at runtime, enabling adding/removing VTL0-exposed SCSI disks backed by VTL2 NVMe namespaces or VTL2 SCSI LUNs.

Changes:

• Add vtl2-settings interactive console command with show, add-scsi-disk, and rm-scsi-disk subcommands.
• Cache VTL2 settings in VmResources and implement a helper to send updated settings via the GED RPC.
• Fix NVMe admin worker behavior by no longer canceling namespace-change polling immediately after adding a namespace.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
vm/devices/storage/nvme/src/workers/admin.rs	Stops prematurely canceling namespace-change polling after a namespace is added.
openvmm/openvmm_entry/src/storage_builder.rs	Exposes VTL2 controller instance IDs for reuse when building VTL2 settings updates from the console.
openvmm/openvmm_entry/src/lib.rs	Implements VTL2 settings caching + GED update helper, and adds the vtl2-settings interactive console command flow.

[mattkur]

Thanks for doing this! Just the output needs to be changed (I think?), but otherwise looks good to me.

[mattkur]

We generally prefer to use the tracing crate here, e.g. tracing::error!.

[alandau]

We have an interactive CLI here, the user is issuing commands, and IMO should get the result on stdout/stderr. Tracing is dev-internal output that is issued during command execution. IOW, I deliberately made this eprintln instead of tracing. Let me know if you still believe tracing fits better here and I'll change.

[alandau]

BTW, existing commands follow the same logic. E.g. inspect prints to stdout and restart-vnc prints errors to stderr.

[mattkur]

ditto on the tracing comment