Simplify GDB memory access by borrowing sandbox memory manager

[ludfjig]

Noticed this ugly code when reviewing another PR and thought it could be cleaned up. MemoryManager already contains everything needed for gdb so no need to clone it as we can borrow it instead. Also fixes potential stale memory access since snapshot restore can replace snapshot and scratch memory, and the cloned manager could potentially be out of sync. Also removed some now unnecessary synchronization and plumbing

[Copilot]

Pull request overview

This PR refactors the GDB memory-access path in hyperlight_host to borrow the sandbox’s in-use SandboxMemoryManager rather than cloning and mutex-wrapping it, aiming to avoid stale memory views after snapshot restore and to simplify the init/run/dispatch plumbing.

Changes:

• Remove the cloned SandboxMemoryManager + Arc<Mutex<…>> plumbing from sandbox initialization and VM dispatch paths.
• Replace DebugMemoryAccess (owned, mutex-backed) with DebugMemoryView (borrowed view) for GDB memory operations.
• Drop Clone on SandboxMemoryManager and update call sites/tests accordingly.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/hyperlight_host/src/sandbox/uninitialized_evolve.rs	Removes GDB-specific cloned/mutex memory-manager plumbing during evolve.
src/hyperlight_host/src/sandbox/initialized_multi_use.rs	Removes stored debug memory manager and simplifies dispatch/init signatures.
src/hyperlight_host/src/mem/mgr.rs	Removes Clone derive from SandboxMemoryManager.
src/hyperlight_host/src/hypervisor/mod.rs	Updates hypervisor tests to match the simplified initialise signature.
src/hyperlight_host/src/hypervisor/hyperlight_vm/x86_64.rs	Updates initialise/dispatch/debug handling to use borrowed DebugMemoryView.
src/hyperlight_host/src/hypervisor/hyperlight_vm/mod.rs	Updates run to pass the live mem_mgr into debug handling without extra handles.
src/hyperlight_host/src/hypervisor/hyperlight_vm/aarch64.rs	Updates initialise/dispatch calls to match the simplified run signature.
src/hyperlight_host/src/hypervisor/gdb/mod.rs	Introduces DebugMemoryView and refactors GDB mem-access tests/utilities.

Suppressed comments (1)

src/hyperlight_host/src/hypervisor/gdb/mod.rs:551

• Same issue as the single-byte write test: this writes to a GPA that resolves to BaseGpaRegion::Mmap, but DebugMemoryView::write only permits scratch (and snapshot under unshared_snapshot_mem). The test should either expect WriteToReadOnly or write into scratch and validate scratch_mem.

            let write_data = [0xAAu8; 16];
            memory
                .access()
                .write(&write_data, (BASE_VIRT + offset) as u64)
                .unwrap();

            let slice = unsafe { memory.mmap_slice() };
            assert_eq!(slice[offset..offset + 16], write_data);

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.