feat(vmm): add HypervisorProbe for post-failure VM diagnostics#430
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macOS Hypervisor.framework returns HV_NO_RESOURCES (0xfae94005) when the 128 VM address space limit is exhausted, but libkrun discards the specific error code and collapses all failures to EINVAL (-22). Add a HypervisorProbe trait that provides platform-abstracted post-failure diagnostics. On macOS, when krun_start_enter() fails, the HvfProbe calls hv_vm_create() directly to reproduce and identify the exact HVF error: - HV_NO_RESOURCES → ResourceExhausted with actionable message - HV_SUCCESS → not HVF-related, return original error - HV_BUSY → VM created but failed post-creation - HV_DENIED → missing entitlement This is zero-cost on the happy path — the probe only runs after failure. Changes: - Add ResourceExhausted error variant to BoxliteError - Add HypervisorProbe trait with HvfProbe (macOS) and KvmProbe (Linux) - Wire probe into KrunVmmInstance::enter() failure path - Improve EINVAL message in check_status() to list both causes - Add ResourceExhausted to FFI error codes
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Summary
HypervisorProbetrait for platform-abstracted hypervisor validation withstartup_check()anddiagnose_create_failure()methodskrun_start_enter()fails,HvfProbecallshv_vm_create()directly to get the exact HVF error code that libkrun discards (collapses all to EINVAL)HV_NO_RESOURCES→ResourceExhaustedwith actionable message (address space limit),HV_DENIED→ entitlement error,HV_BUSY→ post-creation failureContext
macOS Hypervisor.framework has a hard limit of 128 VM address spaces (
kern.hv.max_address_spaces). When exhausted,hv_vm_create()returnsHV_NO_RESOURCES(0xfae94005), but libkrun discards the code athvf/src/lib.rs:260and returns generic-EINVAL(-22). Users see a misleading "rootfs" error.Changes
src/shared/src/errors.rsResourceExhausted(String)variantsrc/boxlite/src/system_check.rsHypervisorProbetrait,HvfProbe(macOS),KvmProbe(Linux), HVF FFIsrc/boxlite/src/vmm/krun/engine.rsenter()failure pathsrc/boxlite/src/vmm/krun/mod.rscheck_status()src/ffi/src/error.rsResourceExhausted = 20to FFI error codessdks/c/include/boxlite.hTest plan
cargo clippy -p boxlite -p boxlite-shared --tests -- -D warnings(clean)cargo test -p boxlite --lib(614 passed, 0 failed)cargo test -p boxlite-shared(1 passed)hvf_ffi_constants)hvf_probe_startup_check)system_check_runs)