Run guard page crash tests on Windows by DanielTangnes · Pull Request #1899 · hyperlight-dev/hyperlight

DanielTangnes · 2026-10-07T21:04:51Z

guard_page_crash_test (read/write/exec on the leading guard page of ExclusiveSharedMemory) runs on Linux and Windows. It uses the subprocess approach from #1498.

What changed:

test_path, run_guard_page_subprocess and killed_by_access_violation live in a small guard_page_subprocess test module that both shims use. The bodies are unchanged, so git diff --color-moved shows them as a move.
The three tests print reached_guard / survived_guard around the bad access. The shim reruns the current test binary with --ignored --exact for each one.
The module is gated on all(not(miri), any(target_os = "linux", windows)).
Removed the signal-hook-registry dev-dependency. The SIGSEGV hook in these tests was its only user.

A side effect on Linux: the old shim spawned cargo test without --profile, so under just test release it rebuilt and checked a debug binary. Rerunning current_exe() keeps the child on the parent's profile and skips the extra build.

I left macOS out to match the issue. from_file_tests already runs there, but I couldn't check which signal the exec case raises on Apple silicon. Happy to widen the gate if you want it.

Test-only change, so no changelog entry.

Testing (Linux x86_64, KVM host):

cargo test -p hyperlight-host --lib -- mem::shared_mem::tests: 28 passed, 5 ignored
cargo test -p hyperlight-host --profile=release --lib -- guard_page: both shims pass
Sanity check: with the leading guard page left PROT_READ | PROT_WRITE, the shim fails with survived=true (reverted afterwards)
rustfmt and clippy: no findings in shared_mem.rs. I ran these with a 1.98 toolchain rather than the pinned 1.94 and nightly rustfmt, so CI is the real check.
Not run locally: Windows, macOS, just miri-tests, full just test. The Windows run comes from CI.

Could a maintainer add kind/enhancement? I can't set labels from a fork.

🤖 Generated with Claude Code

Copilot

🟢 Approval recommended

The subprocess checks, platform gates, and dependency cleanup are consistent and complete.

0 open findings

What changed in this PR

Enables ExclusiveSharedMemory guard page crash tests on Windows using isolated test subprocesses.

Changes:

Reuses a shared subprocess test harness.
Detects Linux signals and Windows access violations.
Removes the unused direct signal hook dependency.

File	Description
`src/hyperlight_host/src/mem/shared_mem.rs`	Adds cross-platform guard page crash testing.
`src/hyperlight_host/Cargo.toml`	Removes the unused dev dependency.
`Cargo.lock`	Removes the direct dependency edge.

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ludfjig

thanks a lot for this, this is great!

ludfjig · 2026-10-12T18:08:50Z

@DanielTangnes looks like CI is failing. If you could address the formatting and then rebase I'd be happy to merge this :)

The read, write and exec guard page tests rerun the test binary with --exact and check its exit status using the helpers from the from_file guard tests. That works on Windows, where the SIGSEGV hook can't, and keeps the child on the same build profile as the parent. Drop the signal-hook-registry dev-dependency. These tests were its only user. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_011CnFoNrC4zWqRUqoeDzS6P Signed-off-by: danieltangnes <danieltangnes1@gmail.com>

DanielTangnes · 2026-10-14T07:40:54Z

@ludfjig Should be good to go now :)

hyperlight-gh-bot · 2026-10-14T16:47:17Z

Benchmark Results

Measured commit: 7bd0b1aa69e1
Baseline commit: ad05110e17bf

kvm / amd (Linux) (➖ stable)

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`747.90 ns` (➖ 1.01x faster)
`vec_bytes`	`582.51 ns` (➖ 1.00x faster)
		`372.05 µs` (➖ 1.00x slower)

payload_allocation

	`slot_pool_segmented`
`262144`	`522.20 ns` (➖ 1.00x faster)
`65536`	`141.63 ns` (➖ 1.03x faster)

sandboxes

	`create_initialized_and_drop`
`medium`	`81.81 ms` (➖ 1.01x slower)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`7.73 ns` (➖ 1.00x slower)	`7.92 ns` (➖ 1.02x slower)	`8.03 ns` (➖ 1.04x slower)

snapshot_files

	`load_snapshot_unverified`
`small`	`80.04 µs` (➖ 1.15x faster)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`7.66 µs` (➖ 1.13x faster)	`7.02 µs` (➖ 1.03x faster)
`65536`	`2.09 µs` (➖ 1.08x slower)	`1.95 µs` (➖ 1.07x faster)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`6.29 µs` (➖ 1.05x faster)	`6.35 µs` (➖ 1.00x faster)
`8192`	`1.07 µs` (➖ 1.02x faster)	`1.08 µs` (➖ 1.03x slower)
`262144`		`27.44 µs` (➖ 1.00x faster)

kvm / intel (Linux) (➖ stable)

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`665.97 ns` (➖ 1.01x faster)
`vec_bytes`	`521.60 ns` (➖ 1.03x slower)
		`654.73 µs` (➖ 1.00x faster)

payload_allocation

	`slot_pool_segmented`
`262144`	`497.06 ns` (➖ 1.01x faster)
`65536`	`134.32 ns` (➖ 1.00x faster)

sandboxes

	`create_initialized_and_drop`
`medium`	`75.33 ms` (➖ 1.04x faster)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`6.93 ns` (➖ 1.02x faster)	`6.85 ns` (➖ 1.00x faster)	`6.92 ns` (➖ 1.01x faster)

snapshot_files

	`load_snapshot_unverified`
`small`	`46.08 µs` (➖ 1.01x slower)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`7.52 µs` (➖ 1.00x slower)	`7.54 µs` (➖ 1.00x faster)
`65536`	`2.13 µs` (➖ 1.00x faster)	`2.14 µs` (➖ 1.02x slower)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`7.10 µs` (➖ 1.01x faster)	`7.09 µs` (➖ 1.02x faster)
`8192`	`759.78 ns` (➖ 1.03x faster)	`808.14 ns` (➖ 1.08x slower)
`262144`		`30.94 µs` (➖ 1.02x slower)

mshv3 / amd (Linux) (➖ stable)

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`946.82 ns` (➖ 1.02x faster)
`vec_bytes`	`713.64 ns` (➖ 1.01x faster)
		`320.70 µs` (➖ 1.00x faster)

payload_allocation

	`slot_pool_segmented`
`262144`	`674.63 ns` (➖ 1.00x slower)
`65536`	`182.62 ns` (➖ 1.02x faster)

sandboxes

	`create_initialized_and_drop`
`medium`	`58.08 ms` (➖ 1.01x slower)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`9.92 ns` (➖ 1.01x faster)	`9.96 ns` (➖ 1.01x faster)	`9.96 ns` (➖ 1.00x faster)

snapshot_files

	`load_snapshot_unverified`
`small`	`87.66 µs` (➖ 1.02x slower)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`9.56 µs` (➖ 1.01x slower)	`9.00 µs` (➖ 1.05x faster)
`65536`	`2.64 µs` (➖ 1.02x faster)	`2.48 µs` (➖ 1.00x slower)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`8.00 µs` (➖ 1.03x faster)	`8.10 µs` (➖ 1.01x faster)
`8192`	`1.35 µs` (➖ 1.00x slower)	`1.35 µs` (➖ 1.01x faster)
`262144`		`34.89 µs` (➖ 1.01x faster)

mshv3 / intel (Linux) (➖ stable)

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`902.73 ns` (➖ 1.00x slower)
`vec_bytes`	`676.73 ns` (➖ 1.03x slower)
		`639.97 µs` (➖ 1.14x faster)

payload_allocation

	`slot_pool_segmented`
`262144`	`646.18 ns` (➖ 1.01x slower)
`65536`	`169.14 ns` (➖ 1.02x slower)

sandboxes

	`create_initialized_and_drop`
`medium`	`75.84 ms` (➖ 1.07x slower)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`9.72 ns` (➖ 1.01x slower)	`9.46 ns` (➖ 1.00x slower)	`9.17 ns` (➖ 1.00x slower)

snapshot_files

	`load_snapshot_unverified`
`small`	`46.35 µs` (➖ 1.00x slower)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`7.98 µs` (➖ 1.01x slower)	`7.93 µs` (➖ 1.00x slower)
`65536`	`2.27 µs` (➖ 1.00x slower)	`2.26 µs` (➖ 1.01x slower)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`7.64 µs` (➖ 1.01x slower)	`7.53 µs` (➖ 1.01x faster)
`8192`	`945.59 ns` (➖ 1.01x faster)	`926.64 ns` (➖ 1.01x slower)
`262144`		`39.76 µs` (➖ 1.03x faster)

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

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`1.17 µs` (➖ 1.12x faster)
`vec_bytes`	`777.11 ns` (➖ 1.03x faster)
		`2.22 ms` (➖ 1.02x slower)

payload_allocation

	`slot_pool_segmented`
`262144`	`806.03 ns` (➖ 1.02x slower)
`65536`	`239.88 ns` (➖ 1.04x slower)

sandboxes

	`create_initialized_and_drop`
`medium`	`103.60 ms` (➖ 1.03x slower)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`10.14 ns` (➖ 1.05x faster)	`10.17 ns` (➖ 1.02x faster)	`10.35 ns` (➖ 1.03x slower)

snapshot_files

	`load_snapshot_unverified`
`small`	`794.52 µs` (➖ 1.03x slower)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`9.46 µs` (➖ 1.01x faster)	`9.34 µs` (➖ 1.02x slower)
`65536`	`2.42 µs` (➖ 1.01x slower)	`2.39 µs` (➖ 1.02x slower)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`9.11 µs` (➖ 1.02x faster)	`9.05 µs` (➖ 1.01x faster)
`8192`	`1.31 µs` (➖ 1.04x faster)	`1.29 µs` (➖ 1.00x faster)
`262144`		`48.44 µs` (➖ 1.26x slower)

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

No benchmark improved or regressed.

Benchmark Results

function_call_codec

	`encode_control`	`decode_vec_bytes_copy`
`byte_chunks`	`1.22 µs` (➖ 1.01x faster)
`vec_bytes`	`795.06 ns` (➖ 1.02x slower)
		`2.96 ms` (➖ 1.05x faster)

payload_allocation

	`slot_pool_segmented`
`262144`	`729.71 ns` (➖ 1.02x faster)
`65536`	`213.13 ns` (➖ 1.16x faster)

sandboxes

	`create_initialized_and_drop`
`medium`	`101.06 ms` (➖ 1.18x faster)

slot_pool

	`alloc_dealloc_1500`	`alloc_dealloc_4096`	`alloc_dealloc_128`
	`10.07 ns` (➖ 1.09x faster)	`9.96 ns` (➖ 1.01x faster)	`10.03 ns` (➖ 1.01x slower)

snapshot_files

	`load_snapshot_unverified`
`small`	`486.19 µs` (➖ 1.26x faster)

virtq_readonly

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`262144`	`7.85 µs` (➖ 1.03x slower)	`7.82 µs` (➖ 1.01x slower)
`65536`	`2.48 µs` (➖ 1.07x slower)	`2.39 µs` (➖ 1.02x slower)

virtq_readwrite

	`slot_pool_segmented_fragmented`	`slot_pool_segmented`
`65536`	`8.45 µs` (➖ 1.03x faster)	`8.48 µs` (➖ 1.03x faster)
`8192`	`1.14 µs` (➖ 1.14x faster)	`1.09 µs` (➖ 1.02x faster)
`262144`		`40.14 µs` (➖ 1.14x faster)

_{Reported by cargo ci bench-report --candidate run:38528262223 --config-file bench_report.toml.}

ludfjig

thanks!!

DanielTangnes marked this pull request as ready for review October 7, 2026 21:11

Copilot AI balanced review requested due to automatic review settings October 7, 2026 21:11

DanielTangnes requested review from andreiltd, danbugs, dblnz, devigned, jprendes, jsturtevant, ludfjig, simongdavies, squillace and syntactically as code owners October 7, 2026 21:11

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ludfjig added the kind/enhancement For PRs adding features, improving functionality, docs, tests, etc. label Oct 12, 2026

ludfjig previously approved these changes Oct 12, 2026

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DanielTangnes dismissed ludfjig’s stale review via 7bd0b1a October 14, 2026 07:25

DanielTangnes force-pushed the windows-guard-page-tests branch from edca0d5 to 7bd0b1a Compare October 14, 2026 07:25

ludfjig approved these changes Oct 14, 2026

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ludfjig merged commit b8783e8 into hyperlight-dev:main Oct 14, 2026
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ludfjig commented Oct 12, 2026

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hyperlight-gh-bot Bot commented Oct 14, 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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