debug: 0.939 device: 0.890 graphic: 0.846 performance: 0.811 PID: 0.560 semantic: 0.498 network: 0.474 socket: 0.472 boot: 0.416 other: 0.359 vnc: 0.354 files: 0.341 permissions: 0.324 KVM: 0.056 Attaching WinDbg to a Windows guest on Windows host causes hang Description of problem: Attempting to attach WinDbg to a Windows guest on a Windows host causes qemu to lockup while using real serial ports. This has been an issue for some time (years if I'm remembering correctly) I just haven't reported it. Steps to reproduce: 1. Enable debug in Windows guest 2. Create a DB9 between 2 COM ports 3. Power guest 4. Attach WinDbg to 2nd COM port not in use by the guest Additional information: