With the HVF in-kernel GICv3, QEMU's usb-storage races on the status packet and Windows Setup stalls 10 s after every burst of reads when installing from the ISO (utmapp/UTM#7970). Use the emulated interrupt controller until upstream QEMU gets the fix from the UTM fork. Record the investigation in windows11-arm64-install-speed.md. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>