feat: pass file mapping info via PEB with label support#1322
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simongdavies merged 1 commit intohyperlight-dev:mainfrom Mar 19, 2026
Merged
feat: pass file mapping info via PEB with label support#1322simongdavies merged 1 commit intohyperlight-dev:mainfrom
simongdavies merged 1 commit intohyperlight-dev:mainfrom
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Pull request overview
This PR extends the Hyperlight host↔guest ABI by adding file-mapping metadata (guest address, size, label) to the PEB, enabling guests to discover host-mapped files and their identities. It reserves space for a fixed-size FileMappingInfo array immediately after the PEB to keep the layout stable.
Changes:
- Add
FileMappingInfo+MAX_FILE_MAPPINGSand extendHyperlightPEBwith afile_mappingsdescriptor. - Add optional
labelsupport tomap_file_cow, validate mapping overlaps, and enforce the max mapping count. - Update memory layout sizing to reserve space for the PEB + mappings array, and write mapping entries into the PEB at map time / evolve time.
Reviewed changes
Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| src/hyperlight_host/src/sandbox/uninitialized_evolve.rs | Writes file mapping metadata into the PEB during evolve for deferred mappings. |
| src/hyperlight_host/src/sandbox/uninitialized.rs | Adds label parameter + limit/overlap validation for deferred file mappings. |
| src/hyperlight_host/src/sandbox/initialized_multi_use.rs | Adds label parameter, validates overlaps, writes mapping metadata into the PEB, updates tests for new signature. |
| src/hyperlight_host/src/sandbox/file_mapping.rs | Stores a fixed-size C-string label in prepared mappings and validates/truncates labels. |
| src/hyperlight_host/src/mem/mgr.rs | Adds write_file_mapping_entry to write FileMappingInfo entries into the PEB’s reserved array. |
| src/hyperlight_host/src/mem/layout.rs | Reserves space after the PEB for MAX_FILE_MAPPINGS entries and wires up PEB offsets/pointers. |
| src/hyperlight_host/examples/crashdump/main.rs | Updates map_file_cow calls for the new label parameter. |
| src/hyperlight_common/src/mem.rs | Adds shared ABI types/constants and extends HyperlightPEB with file_mappings. |
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jsturtevant
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Mar 19, 2026
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Mar 19, 2026
Cherry-pick of hyperlight-dev#1322. Add FileMappingInfo struct (guest_addr, size, label) and file_mappings field to HyperlightPEB so file mapping metadata is communicated to the guest through the PEB. Space for MAX_FILE_MAPPINGS (32) entries is statically reserved after the PEB struct to avoid dynamic layout changes. - Add label parameter to map_file_cow (optional, defaults to filename) - Add shared memory overlap validation (full mapped range) - Add inter-mapping overlap detection - Add write_file_mapping_entry on SandboxMemoryManager - Add MAX_FILE_MAPPINGS limit enforcement at registration time - Update PEB region sizing in get_memory_regions and layout tests
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Add FileMappingInfo struct (guest_addr, size, label) and file_mappings field to HyperlightPEB so file mapping metadata is communicated to the guest through the PEB. Space for MAX_FILE_MAPPINGS (32) entries is statically reserved after the PEB struct to avoid dynamic layout changes. - Add label parameter to map_file_cow (optional, defaults to filename) - Add shared memory overlap validation (full mapped range) - Add inter-mapping overlap detection - Add write_file_mapping_entry on SandboxMemoryManager - Add MAX_FILE_MAPPINGS limit enforcement at registration time - Update PEB region sizing in get_memory_regions and layout tests Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>
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danbugs
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LGTM to me. Just 2 questions and 1 nit.
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Add FileMappingInfo struct (guest_addr, size, label) and file_mappings field to HyperlightPEB so file mapping metadata is communicated to the guest through the PEB. Space for MAX_FILE_MAPPINGS (32) entries is statically reserved after the PEB struct to avoid dynamic layout changes.