MigTD: Remove lock for REPORTSTATUS flags#717
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The interrupt handler (vmcall_service_callback) previously held a spin::Mutex on VMCALL_MIG_REPORTSTATUS_FLAGS (BTreeMap). On the single-threaded TDX guest, if an interrupt fires while non-ISR code holds the same lock, the ISR spins forever — guaranteed deadlock. Replace the per-request BTreeMap<u64, AtomicBool> + Mutex with direct buffer polling: each report_status poll_fn checks its own private shared-memory buffer's datastatus field on every poll cycle. This is correct because: - The buffer is the ground truth for VMM completion - Any interrupt (WFR or otherwise) wakes the CPU from HLT, triggering poll_tasks() which re-polls all pending futures - Each consumer checks its own buffer — no shared state, no interference between concurrent report_status calls The ISR now only sets VMCALL_SERVICE_FLAG (for wait_for_request). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Signed-off-by: Haitao Huang <haitaohuang@microsoft.com>
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The build failure seems network issue |
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The interrupt handler (vmcall_service_callback) previously held a spin::Mutex on VMCALL_MIG_REPORTSTATUS_FLAGS (BTreeMap). On the single-threaded TDX guest, if an interrupt fires while non-ISR code holds the same lock, the ISR spins forever — guaranteed deadlock.
Replace the per-request BTreeMap<u64, AtomicBool> + Mutex with direct buffer polling: each report_status poll_fn checks its own private shared-memory buffer's datastatus field on every poll cycle. This is correct because:
The ISR now only sets VMCALL_SERVICE_FLAG (for wait_for_request).