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Pull request overview
This PR aims to bring Hyperlight’s snapshot-driven copy-on-write (CoW) workflow into the Wasm path by deferring sandbox restores and enabling Wasmtime “memory image” support via VA remapping.
Changes:
- Add
needs_restore/restore_if_needed()to defer restoring the runtime snapshot until the next module load, reducing eager restore overhead. - Add
WasmSandbox::load_from_snapshot()to create a loaded sandbox by restoring a snapshot taken from aLoadedWasmSandbox. - Implement Wasmtime memory image APIs by copying VA mappings and converting writable pages to CoW mappings.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 8 comments.
| File | Description |
|---|---|
src/hyperlight_wasm/src/sandbox/wasm_sandbox.rs |
Defers restore on unload via needs_restore, adds load_from_snapshot, and wires restore into some load paths. |
src/hyperlight_wasm_runtime/src/platform.rs |
Implements Wasmtime memory image creation/mapping via page-table remaps and CoW conversion. |
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dblnz
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Apr 2, 2026
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Good work! 👍
I don't really have much to say to object to merging this, except maybe the Cargo.lock comment
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ludfjig
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Apr 2, 2026
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One comment but not blocking
Signed-off-by: Lucy Menon <168595099+syntactically@users.noreply.github.com>
When we are loading from a snapshot, we can get away with just a restore and never going through a wasmtime load. Signed-off-by: Lucy Menon <168595099+syntactically@users.noreply.github.com>
Signed-off-by: Lucy Menon <168595099+syntactically@users.noreply.github.com>
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dblnz
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…o restore Tie together more closely the logic on when to restore the sandbox with access to the sandbox, in a more self-contained and easier-to-reason-about sub-module. Signed-off-by: Lucy Menon <168595099+syntactically@users.noreply.github.com>
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…o restore Signed-off-by: Lucy Menon <168595099+syntactically@users.noreply.github.com>
…o restore Signed-off-by: Lucy Menon <168595099+syntactically@users.noreply.github.com>
ludfjig
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jsturtevant
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This should finally get the main benefits of the hyperlight core snapshot-focused CoW workflow into wasm.