Changes to allow different toolchains for host and guest by simongdavies · Pull Request #1962 · hyperlight-dev/hyperlight

simongdavies · 2026-10-20T15:46:35Z

Enables different toolchains for host and guest.

Host - 1.99.1
Guest - 1.94.1

No change to MSRV.

Minor changes to resolve warnings from move to 1.99

Copilot

🔵 Needs a closer look

The guest debug-information regression remains unresolved, and cross-platform CI, Nix, and container changes need build validation.

1 open issue

Set debug info level for guest builds in all workflows · New

What changed in this PR

Separates Hyperlight’s host and guest Rust toolchains without changing the minimum supported Rust version.

Changes:

Pins host builds to Rust 1.99.1 and guest builds to 1.94.1.
Updates CI, Nix, containers, and contributor documentation for separate toolchains.
Resolves compiler and lint warnings.

File	Description
src/tests/rust_guests/rust-toolchain.toml	Pins Rust guest toolchain.
src/hyperlight_testing/src/tracing_subscriber.rs	Removes redundant formatting borrows.
src/hyperlight_host/tests/sandbox_host_tests.rs	Removes obsolete import.
src/hyperlight_host/build.rs	Removes redundant formatting borrow.
src/hyperlight_guest_capi/rust-toolchain.toml	Pins C API guest toolchain.
src/hyperlight_component_util/src/util.rs	Removes redundant formatting borrow.
src/hyperlight_component_util/src/rtypes.rs	Iterates map keys directly.
src/hyperlight_component_util/src/emit.rs	Iterates map values directly.
rust-toolchain.toml	Pins host toolchain and components.
flake.nix	Supports separate toolchain selection.
CONTRIBUTING.md	Documents guest toolchain selection.
.github/workflows/ValidatePullRequest.yml	Installs both toolchains.
.github/workflows/RustNightly.yml	Updates setup and guest cache keys.
.github/workflows/RegenSnapshotGoldens.yml	Installs both toolchains.
.github/workflows/PrimeCaches.yml	Installs both toolchains.
.github/workflows/dep_update_guest_locks.yml	Installs both toolchains.
.github/workflows/dep_run_examples.yml	Installs both toolchains.
.github/workflows/dep_miri.yml	Uses file-based toolchain setup.
.github/workflows/dep_fuzzing.yml	Installs both toolchains.
.github/workflows/dep_code_checks.yml	Updates setup and guest cache keys.
.github/workflows/dep_build_test.yml	Installs both toolchains.
.github/workflows/dep_build_guests.yml	Supports guest pins and older commits.
.github/workflows/dep_benchmarks.yml	Installs both toolchains.
.github/workflows/CreateRelease.yml	Installs both toolchains.
.github/workflows/CreateDevcontainerImage.yml	Reads and passes both toolchain versions.
.github/workflows/Coverage.yml	Installs both toolchains.
.github/workflows/copilot-setup-steps.yml	Consolidates toolchain setup.
.github/workflows/CargoPublish.yml	Installs both toolchains.
.github/workflows/CargoAudit.yml	Uses file-based toolchain selection.
.devcontainer/Dockerfile	Installs separate host and guest toolchains.

_{Review effort: Balanced}

ludfjig

just some more regarding caching since I've recently tried to fix this

Host move to 1.99.1 Guest fixed at 1.94.1 until hyperlight target is upstreamed Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: ab05d8c1-959f-4723-9dce-971b8be8559a Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

hyperlight-gh-bot · 2026-10-22T19:09:04Z

Benchmark Results

Measured commit: 59e08c6ee5f1
Baseline commit: 3f2ed9becd6e

kvm / amd (Linux) (➖ stable)

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`772.39 ns` (➖ 1.01x slower)
`vec_bytes`	`579.68 ns` (➖ 1.00x faster)
		`374.15 µs` (➖ 1.01x faster)

payload_allocation

	`slot_pool_segmented`
`262144`	`523.59 ns` (➖ 1.00x faster)
`65536`	`141.58 ns` (➖ 1.01x faster)

sandboxes

	`create_initialized_and_drop`
`medium`	`83.21 ms` (➖ 1.01x faster)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`7.70 ns` (➖ 1.01x faster)	`7.70 ns` (➖ 1.00x faster)	`7.69 ns` (➖ 1.00x faster)

snapshot_files

	`load_snapshot_unverified`
`small`	`92.92 µs` (➖ 1.01x slower)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`7.20 µs` (➖ 1.00x faster)	`7.73 µs` (➖ 1.09x slower)
`65536`	`2.04 µs` (➖ 1.06x slower)	`1.92 µs` (➖ 1.10x faster)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`6.43 µs` (➖ 1.01x slower)	`6.13 µs` (➖ 1.02x faster)
`8192`	`1.04 µs` (➖ 1.02x slower)	`1.01 µs` (➖ 1.00x faster)
`262144`		`27.17 µs` (➖ 1.00x slower)

kvm / intel (Linux) (➖ stable)

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`773.59 ns` (➖ 1.05x slower)
`vec_bytes`	`585.68 ns` (➖ 1.01x slower)
		`734.95 µs` (➖ 1.05x slower)

payload_allocation

	`slot_pool_segmented`
`262144`	`565.63 ns` (➖ 1.01x faster)
`65536`	`191.82 ns` (➖ 1.02x faster)

sandboxes

	`create_initialized_and_drop`
`medium`	`79.92 ms` (➖ 1.01x faster)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`7.55 ns` (➖ 1.03x faster)	`7.55 ns` (➖ 1.03x faster)	`7.58 ns` (➖ 1.02x faster)

snapshot_files

	`load_snapshot_unverified`
`small`	`49.79 µs` (➖ 1.04x slower)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`8.65 µs` (➖ 1.01x slower)	`8.57 µs` (➖ 1.00x faster)
`65536`	`2.45 µs` (➖ 1.02x slower)	`2.40 µs` (➖ 1.01x faster)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`7.63 µs` (➖ 1.11x faster)	`7.91 µs` (➖ 1.08x faster)
`8192`	`792.27 ns` (➖ 1.04x faster)	`762.84 ns` (➖ 1.05x faster)
`262144`		`34.37 µs` (➖ 1.03x slower)

mshv3 / amd (Linux) (➖ stable)

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`973.41 ns` (➖ 1.03x slower)
`vec_bytes`	`715.25 ns` (➖ 1.03x faster)
		`271.86 µs` (➖ 1.14x faster)

payload_allocation

	`slot_pool_segmented`
`262144`	`717.03 ns` (➖ 1.00x faster)
`65536`	`200.87 ns` (➖ 1.06x slower)

sandboxes

	`create_initialized_and_drop`
`medium`	`63.00 ms` (➖ 1.09x slower)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`9.71 ns` (➖ 1.00x faster)	`9.70 ns` (➖ 1.00x faster)	`9.70 ns` (➖ 1.00x faster)

snapshot_files

	`load_snapshot_unverified`
`small`	`86.57 µs` (➖ 1.00x slower)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`10.01 µs` (➖ 1.01x faster)	`9.66 µs` (➖ 1.01x slower)
`65536`	`2.40 µs` (➖ 1.04x faster)	`2.25 µs` (➖ 1.01x faster)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`8.30 µs` (➖ 1.15x faster)	`8.48 µs` (➖ 1.17x faster)
`8192`	`1.24 µs` (➖ 1.10x faster)	`1.22 µs` (➖ 1.02x slower)
`262144`		`35.72 µs` (➖ 1.08x faster)

mshv3 / intel (Linux) (➖ stable)

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`902.42 ns` (➖ 1.02x faster)
`vec_bytes`	`671.53 ns` (➖ 1.02x slower)
		`708.18 µs` (➖ 1.07x faster)

payload_allocation

	`slot_pool_segmented`
`262144`	`629.29 ns` (➖ 1.01x faster)
`65536`	`244.48 ns` (➖ 1.02x slower)

sandboxes

	`create_initialized_and_drop`
`medium`	`60.52 ms` (➖ 1.14x faster)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`9.16 ns` (➖ 1.01x slower)	`9.28 ns` (➖ 1.01x slower)	`9.18 ns` (➖ 1.00x slower)

snapshot_files

	`load_snapshot_unverified`
`small`	`45.92 µs` (➖ 1.03x slower)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`8.03 µs` (➖ 1.00x slower)	`7.97 µs` (➖ 1.00x slower)
`65536`	`2.29 µs` (➖ 1.00x slower)	`2.36 µs` (➖ 1.03x slower)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`7.44 µs` (➖ 1.00x faster)	`7.40 µs` (➖ 1.00x faster)
`8192`	`913.53 ns` (➖ 1.01x slower)	`899.64 ns` (➖ 1.03x faster)
`262144`		`41.35 µs` (➖ 1.05x slower)

hyperv-ws2025 / amd (Windows) (➖ stable)

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`1.16 µs` (➖ 1.05x faster)
`vec_bytes`	`856.49 ns` (➖ 1.12x slower)
		`1.92 ms` (➖ 1.00x faster)

payload_allocation

	`slot_pool_segmented`
`262144`	`786.82 ns` (➖ 1.01x faster)
`65536`	`229.64 ns` (➖ 1.07x faster)

sandboxes

	`create_initialized_and_drop`
`medium`	`84.24 ms` (➖ 1.05x slower)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`9.90 ns` (➖ 1.00x slower)	`10.03 ns` (➖ 1.01x slower)	`9.99 ns` (➖ 1.00x slower)

snapshot_files

	`load_snapshot_unverified`
`small`	`906.18 µs` (➖ 1.44x slower)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`9.53 µs` (➖ 1.05x faster)	`9.65 µs` (➖ 1.01x faster)
`65536`	`2.40 µs` (➖ 1.01x slower)	`2.53 µs` (➖ 1.07x slower)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`9.62 µs` (➖ 1.04x slower)	`10.12 µs` (➖ 1.10x slower)
`8192`	`1.34 µs` (➖ 1.07x slower)	`1.33 µs` (➖ 1.04x slower)
`262144`		`42.29 µs` (➖ 1.06x faster)

hyperv-ws2025 / intel (Windows) (➖ stable)

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`1.20 µs` (➖ 1.00x faster)
`vec_bytes`	`764.45 ns` (➖ 1.00x slower)
		`2.93 ms` (➖ 1.03x faster)

payload_allocation

	`slot_pool_segmented`
`262144`	`734.72 ns` (➖ 1.00x faster)
`65536`	`209.40 ns` (➖ 1.02x slower)

sandboxes

	`create_initialized_and_drop`
`medium`	`101.75 ms` (➖ 1.09x faster)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`9.57 ns` (➖ 1.00x slower)	`10.24 ns` (➖ 1.04x slower)	`9.59 ns` (➖ 1.00x slower)

snapshot_files

	`load_snapshot_unverified`
`small`	`624.38 µs` (➖ 1.12x slower)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`7.60 µs` (➖ 1.03x slower)	`7.62 µs` (➖ 1.03x slower)
`65536`	`2.26 µs` (➖ 1.01x slower)	`2.29 µs` (➖ 1.07x faster)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`8.42 µs` (➖ 1.15x faster)	`8.33 µs` (➖ 1.00x faster)
`8192`	`1.04 µs` (➖ 1.00x faster)	`1.10 µs` (➖ 1.05x slower)
`262144`		`41.14 µs` (➖ 1.22x faster)

_{Reported by cargo ci bench-report --candidate run:39828625144 --config-file bench_report.toml.}

Copilot AI balanced review requested due to automatic review settings October 20, 2026 15:46

simongdavies added the kind/dependencies For PRs that update dependencies or related components label Oct 20, 2026

simongdavies requested review from andreiltd, danbugs, dblnz, devigned, jprendes, jsturtevant, ludfjig, squillace and syntactically as code owners October 20, 2026 15:46

Copilot started reviewing on behalf of simongdavies October 20, 2026 15:50

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simongdavies force-pushed the simongdavies-split-rust-toolchains branch from 7921620 to 9c6a3cb Compare October 22, 2026 11:14

simongdavies mentioned this pull request Oct 22, 2026

Exclude hyperlight-guest-capi from root workspace #1970

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ludfjig requested changes Oct 22, 2026

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simongdavies and others added 7 commits October 22, 2026 19:06

Changes to allow different toolchains for host and guest

cdaec76

Host move to 1.99.1 Guest fixed at 1.94.1 until hyperlight target is upstreamed Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

Update to version 2.1.0 of the common wokflow and other fixes

77fe3cc

Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

review fixes and move to common workflow v2.2.0

f7c2c30

Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

update to v2.3.0 of the common workflow

9193841

Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

fix guest toolchain check

2a6a8c8

Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

more review fixes

ea6255c

Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

Fix audit and guest sysroot cache settings

59e08c6

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: ab05d8c1-959f-4723-9dce-971b8be8559a Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

simongdavies force-pushed the simongdavies-split-rust-toolchains branch from 8a195fd to 59e08c6 Compare October 22, 2026 18:07

ludfjig approved these changes Oct 22, 2026

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simongdavies enabled auto-merge (squash) October 22, 2026 18:27

simongdavies merged commit fd9fc1e into main Oct 22, 2026
121 of 127 checks passed

simongdavies deleted the simongdavies-split-rust-toolchains branch October 22, 2026 19:40

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hyperlight-gh-bot Bot commented Oct 22, 2026

Benchmark Results

Benchmark Results

function_call_codec

payload_allocation

sandboxes

slot_pool

snapshot_files

virtq_readonly

virtq_readwrite

Benchmark Results

function_call_codec

payload_allocation

sandboxes

slot_pool

snapshot_files

virtq_readonly

virtq_readwrite

Benchmark Results

function_call_codec

payload_allocation

sandboxes

slot_pool

snapshot_files

virtq_readonly

virtq_readwrite

Benchmark Results

function_call_codec

payload_allocation

sandboxes

slot_pool

snapshot_files

virtq_readonly

virtq_readwrite

Benchmark Results

function_call_codec

payload_allocation

sandboxes

slot_pool

snapshot_files

virtq_readonly

virtq_readwrite

Benchmark Results

function_call_codec

payload_allocation

sandboxes

slot_pool

snapshot_files

virtq_readonly

virtq_readwrite

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Reviewers

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