prometeu-runtime/discussion/workflow/plans/PLN-0053-move-logging-ownership-to-systemos.md

id	ticket	title	status	created	ref_decisions	tags
PLN-0053	system-os-service-ownership-and-module-layout	Move Logging Ownership To SystemOS	done	2026-05-14	DEC-0024	runtime os services module-layout vm window-manager logging

Briefing

Move LogService ownership from VirtualMachineRuntime to SystemOS, while allowing VM execution code to use OS logging through an explicit reference or handle.

Source Decisions

• DEC-0024: LogService SHALL move from VirtualMachineRuntime to SystemOS; VM execution MAY use an explicit OS logging reference or handle but MUST NOT own logging.

Target

Make logging an OS-owned service and reduce VirtualMachineRuntime to a user of logging rather than its owner.

Dependencies

• Source decision: DEC-0024.
• Depends on PLN-0051.
• May run after or alongside PLN-0052, but code integration is simpler after SystemOS service ownership is established.

Scope

• Add LogService ownership to SystemOS.
• Remove log_service: LogService from VirtualMachineRuntime.
• Update VM runtime methods that read/write logs to receive logging access from SystemOS or a narrow explicit handle.
• Update construction paths so LogService::new(4096) is owned by SystemOS.
• Update tests that currently inspect runtime-owned logs.

Out of Scope

• Do not change log capacity or log record semantics.
• Do not change VM syscall behavior except for the ownership path.
• Do not introduce compatibility accessors that imply VM ownership.
• Do not move filesystem or memcard ownership in this plan.

Execution Plan

1. Add a LogService field to SystemOS and initialize it in SystemOS::new.
2. Remove LogService initialization and storage from VirtualMachineRuntime::new.
3. Update VM logging call paths in dispatch, tick, lifecycle, and tests to use OS-owned logging.
4. If borrow constraints require it, introduce a narrow logging handle/reference parameter at the call boundary instead of giving the VM ownership.
5. Update all tests that assert logging behavior.
6. Run formatting and tests.

Acceptance Criteria

• VirtualMachineRuntime no longer stores LogService.
• SystemOS owns LogService.
• VM execution can still emit and expose logs through the existing behavior.
• No compatibility API suggests that logging remains VM-owned.
• Existing logging tests pass or are updated to assert OS ownership.

Tests / Validation

• Run cargo test -p prometeu-system.
• Include focused tests covering VM log writes and reads after ownership moves to SystemOS.

Risks

• Borrowing constraints around NativeInterface may require a narrow access pattern rather than simply borrowing all of SystemOS.
• Tests that currently construct only VirtualMachineRuntime may need to move to SystemOS construction to reflect the new owner.

Affected Artifacts

• crates/console/prometeu-system/src/os/system_os.rs
• crates/console/prometeu-system/src/services/vm_runtime/**
• Tests under the VM runtime module