opentmk: add config-patch protocol and bootable VHD build

[mayank-microsoft]

Summary

Add OpenTMK's test-selection config mechanism and the tooling to build a
bootable OpenTMK VHD.

OpenTMK tests are selected by patching a small config region embedded in
the built .efi, rather than by rebuilding per test. This PR adds that
protocol, the guest-side dispatch that reads it, and a
cargo xflowey build-opentmk pipeline that builds the .efi and
packages it into a bootable VHD.

Changes

• New crate opentmk_protocol — the embedded config region format
  (OPENTMK_CONFIG_MAGIC / OpenTmkConfig / TestConfig) and
  patch_opentmk_config, which patches a built .efi in place to select
  the backend/test to run.
• New crate opentmk/opentmk_disk — builds a fixed VHD (GPT + EFI
  system partition) around an OpenTMK .efi, optionally patching the
  config.
• OpenTMK guest — reads the embedded .tmkcfg config region and
  dispatches to the selected backend/test via the opentmk_tests! /
  opentmk_backends! macros.
• flowey cargo xflowey build-opentmk pipeline — builds the .efi
  and packages it into a VHD using opentmk_disk.
• Register the two new crates in the workspace.

No new external dependencies: opentmk_disk's deps (gptman,
fscommon, disk_vhd1, guid, tempfile) are already workspace
dependencies.

Testing

• cargo build -p opentmk_protocol -p opentmk_disk
• cargo build -p opentmk --target x86_64-unknown-uefi (stable)
• cargo build -p flowey_hvlite -p flowey_lib_hvlite
• cargo xflowey build-opentmk --help

[github-actions]

⚠️ Unsafe Code Detected

This PR modifies files containing unsafe Rust code. Extra scrutiny is required during review.

For more on why we check whole files, instead of just diffs, check out the Rustonomicon

[Copilot]

Pull request overview

This PR introduces a host-patchable “config region” protocol for selecting OpenTMK tests without rebuilding, plus shared tooling to package an OpenTMK UEFI binary into a bootable fixed VHD, and a new local-only cargo xflowey build-opentmk pipeline to produce those artifacts.

Changes:

• Add opentmk_protocol defining the embedded config region layout, JSON schema, and an in-place patcher for .efi/disk images.
• Add opentmk_disk to build a GPT + FAT32 ESP fixed VHD containing the OpenTMK .efi, optionally patched with test-selection config.
• Update OpenTMK guest-side test dispatch to read the embedded .tmkcfg config region, and add a local-only flowey pipeline (build-opentmk) to build and package artifacts.

Reviewed changes

Copilot reviewed 15 out of 16 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
opentmk/src/tests/mod.rs	Adds backend/test dispatch macros, embeds the .tmkcfg config static, and reads it via volatile load to drive test selection.
opentmk/src/tests/hyperv/mod.rs	Switches Hyper-V tests to macro-driven registration/dispatch with per-test cfg gating.
opentmk/opentmk_disk/src/lib.rs	New crate that builds a bootable fixed VHD (GPT + FAT32 ESP) around an OpenTMK .efi, with optional config patching.
opentmk/opentmk_disk/Cargo.toml	Declares opentmk_disk dependencies (reusing existing workspace deps).
opentmk/Cargo.toml	Adds dependency on opentmk_protocol for guest-side config parsing/static.
opentmk_protocol/src/lib.rs	New no-std protocol crate defining the config region format, JSON schema, and patching logic (+ unit tests).
opentmk_protocol/Cargo.toml	Declares opentmk_protocol dependencies (serde, serde_json, thiserror).
flowey/flowey_lib_hvlite/src/lib.rs	Exposes the new build_opentmk flow node module.
flowey/flowey_lib_hvlite/src/build_opentmk.rs	New flowey node to build opentmk as a UEFI binary and report .efi/.pdb outputs.
flowey/flowey_lib_hvlite/src/_jobs/mod.rs	Registers the new local-only build job for OpenTMK.
flowey/flowey_lib_hvlite/src/_jobs/local_build_opentmk.rs	New local job that packages the built .efi into a VHD via opentmk_disk (optionally patching config).
flowey/flowey_lib_hvlite/Cargo.toml	Adds dependency on opentmk_disk for the packaging step.
flowey/flowey_hvlite/src/pipelines/mod.rs	Adds the BuildOpentmk CLI subcommand entry point.
flowey/flowey_hvlite/src/pipelines/build_opentmk.rs	New local-only cargo xflowey build-opentmk pipeline wiring + CLI flags.
Cargo.toml	Registers opentmk_protocol and opentmk_disk as workspace dependencies.
Cargo.lock	Locks the new workspace crates into the dependency graph.

[Copilot]

Pull request overview

Copilot reviewed 15 out of 16 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 15 out of 16 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 15 out of 16 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

flowey/flowey_hvlite/src/pipelines/build_opentmk.rs:16

• This PR adds a new cargo xflowey build-opentmk pipeline, but the Guide’s list of notable cargo xflowey pipelines doesn’t mention it yet (see Guide/src/dev_guide/dev_tools/xflowey.md, which currently lists build-igvm/restore-packages/vmm-tests-run/cca-tests). Adding at least a brief entry for build-opentmk would help discoverability and keep the dev-tool docs in sync.

/// Build OpenTMK and package it into a bootable VHD.
#[derive(clap::Args)]
pub struct BuildOpentmkCli {
    /// Target architecture for the OpenTMK build. Defaults to x86-64.