uname -a (baseline stock kernel):
DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026     root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64

uname -a (fix-validation kernel, patched sys/bus/smbus/smbus.c):
DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #1: Fri Oct  9 04:55:10 UTC 2026     root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64

cc 8.3 [DragonFly] Release/2019-02-22
kernel build: make -j6 nativekernel KERNCONF=X86_64_GENERIC (RC=0, ~4 min)
>>> Kernel build for X86_64_GENERIC completed on Fri Oct  9 04:58:10 UTC 2026

guest modules: smb.ko available in /boot/kernel (the stock Jul-2 kernel has
"smb" compiled in -- kldstat -v shows "smbus/smb"; the rebuilt kernel from
the repo's X86_64_GENERIC config does not -- "device smb" is absent from
sys/config/X86_64_GENERIC -- so fix-validation runs kldload smb.ko first).

QEMU i440fx + PIIX4 PM at pci0:0:1.3 (8086:7113); intpm attaches but its
IRQ allocation fails on QEMU (SCI owns IRQ 9), so the family-standard
production-code KLD rig (fake controller on nexus) hosts the real chain.