feat: use hyperlight-host 0.16.0 from crates.io

[danbugs]

Summary

Switch hyperlight-host dependency from a git pin on danbugs/hyperlight to hyperlight-host = "0.16.0" from crates.io. This unblocks publishing hyperlight-unikraft to crates.io (closes #4, unblocks #27).

Key changes:

• OCI snapshot format: to_file/from_file_unchecked → save/load with OCI image-layout. Snapshot path changes from snapshot.hls (file) to snapshot/ (directory)
• map_file_cow: 3-arg → 2-arg (label parameter removed upstream)
• restore: restore_preserving_file_mappings removed; initrd is re-mapped after every restore()
• Sparsify removed: OCI format manages storage; sparsify_snapshot and related platform-specific code dropped
• whp-no-surrogate feature removed: now controlled via HYPERLIGHT_MAX_SURROGATES env var at runtime
• max_surrogates API: configure_surrogates(), InstallOptions.max_surrogates, and Runtime::new() 5th arg for mxc integration
• Heap size: reduced default from 2560 MiB to 1280 MiB

Test plan

• cargo check / cargo clippy pass
• CI passes (runtime tests, benchmarks)
• mxc compiles with this branch

[github-actions]

Linux Benchmarks

Details

Benchmark suite	Current: 77c44bd	Previous: 897275c	Ratio
hello_world (median)	20 ms	20 ms	1
pandas (median)	110 ms	110 ms	1
density (per VM)	8 MB	11 MB	0.73
snapshot (disk)	653 MiB	656 MiB	1.00

This comment was automatically generated by workflow using github-action-benchmark.

[github-actions]

Windows Benchmarks

Details

Benchmark suite	Current: 77c44bd	Previous: 897275c	Ratio
hello_world (median)	307 ms	373 ms	0.82
pandas (median)	957 ms	1092 ms	0.88
density (per VM)	7 MB	656 MB	0.010670731707317074
snapshot (disk)	661 MiB	664 MiB	1.00

This comment was automatically generated by workflow using github-action-benchmark.

[Copilot]

Pull request overview

This PR updates hyperlight-unikraft’s host tooling to work directly against upstream hyperlight-dev/hyperlight main (pinned to 69c362b6), primarily by migrating snapshot persistence/loading from a single snapshot.hls file to an OCI image-layout directory (snapshot/) and removing custom-branch-only features/APIs.

Changes:

• Switch hyperlight-host dependency to upstream hyperlight-dev/hyperlight@69c362b6 and drop custom-branch-only features/deps.
• Migrate snapshot persistence and all references from snapshot.hls to OCI layout in snapshot/ (save/load with OciTag).
• Update restore behavior to re-map initrd after restore (replacing the old “preserve file mappings” restore path).

Reviewed changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
host/tests/pyhl_runtime.rs	Updates test install probing from snapshot.hls to snapshot/.
host/src/pyhl.rs	Updates library install/runtime flow to use OCI snapshot directory and upstream snapshot APIs.
host/src/lib.rs	Adapts snapshot save/load to upstream OCI format; removes preserving-restore path and snapshot sparsification.
host/src/bin/pyhl.rs	Updates CLI setup/run to use snapshot/ directory layout and upstream APIs.
host/src/bin/pydriver_run.rs	Updates heap sizing consistent with other host entrypoints.
host/examples/test_cpiovfs.rs	Updates snapshot save path to directory form and simplifies output.
host/examples/pyhl_as_library.rs	Updates example docs to refer to .pyhl/snapshot/.
host/Cargo.toml	Points hyperlight-host to upstream repo/rev; drops no-longer-needed deps/features.
host/Cargo.lock	Lockfile refresh consistent with upstream dependency graph changes.
.github/workflows/benchmarks.yml	Updates snapshot size reporting to handle snapshot/ directory on Linux/Windows.

Comments suppressed due to low confidence (1)

host/src/bin/pyhl.rs:378

• The setup early-return condition only checks that snapshot/ is a directory. A partially-written/empty snapshot dir (e.g., interrupted save) would incorrectly be treated as “installed” unless --force, leaving pyhl run broken. Consider checking for an OCI-layout marker (e.g., snapshot/index.json) and, when proceeding with setup, deleting any existing snapshot path (file or dir) before saving a new snapshot to avoid accumulating stale blobs across repeated --force runs.

    if image_installed(&home) && dst_snapshot.is_dir() && !args.force {
        eprintln!(
            "pyhl: image already installed at {} (use --force to overwrite)",
            home.display()
        );

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