1.8: virt_mshv_vtl: Fixup handling of higher VTL permissions when emulating instructions (#4056) - #4123
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Steven Malis (smalis-msft) merged 1 commit intoAug 4, 2026
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…g instructions (microsoft#4056) A bunch of small fixes to permission handling: * Skip unmapped GPAs (they'll GP later) * Check for execute permissions correctly on ARM (cherry picked from commit aa5b33f)
Steven Malis (smalis-msft)
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release_1.8.2607
Steven Malis (smalis-msft)
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July 31, 2026 17:20
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Pull request overview
This backport aligns release/1.8.2607 with upstream PR #4056 by correcting how instruction emulation distinguishes execute vs data reads when enforcing higher-VTL permissions, and by avoiding VTL-permission hypercalls for unmapped/out-of-range GPAs.
Changes:
- Propagate an
exec: boolsignal through the aarch64 emulator physical-memory read path and use it to validateTranslateMode::ExecutevsTranslateMode::Read. - Ensure
&mut T’sCpu::read_instructionforwarding calls the underlyingread_instruction(notread_memory), preserving execute-vs-data semantics. - In
virt_mshv_vtlx64/arm64 emulation support, skip VTL permission checks for GPAs that are not mapped lower-VTL RAM to prevent whole-hypercall failures on unmapped/out-of-range GPAs.
Reviewed changes
Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| vmm_core/virt_support_aarch64emu/src/emulate.rs | Treat instruction fetches as execute reads when enforcing VTL access during emulation. |
| vm/aarch64/aarch64emu/tests/load_store.rs | Update test CPU implementation signature to match new exec parameter. |
| vm/aarch64/aarch64emu/src/emulator.rs | Thread exec through emulator physical-memory reads and update call sites. |
| vm/aarch64/aarch64emu/src/cpu.rs | Extend Cpu::read_physical_memory with exec and fix read_instruction forwarding. |
| openhcl/virt_mshv_vtl/src/processor/mshv/x64.rs | Skip VTL permission hypercall for non-lower-VTL-RAM GPAs during execute checks. |
| openhcl/virt_mshv_vtl/src/processor/mshv/arm64.rs | Same as x64: avoid hypercall failure on unmapped/out-of-range GPAs. |
Matt LaFayette (Kurjanowicz) (mattkur)
approved these changes
Aug 4, 2026
Steven Malis (smalis-msft)
merged commit Aug 4, 2026
856664c
into
microsoft:release/1.8.2607
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Backport of #4056 to
release/1.8.2607.The cherry-pick of aa5b33f applied cleanly onto
release/1.8.2607with no conflicts and no manual edits.Original PR: #4056
This backport PR was created by an AI agent (GitHub Copilot) on behalf of Steven Malis (@smalis-msft).