Changes from v1: Added portio_list_del() to the wdt_ib700 device
Free pending messages and the vmstate, and get rid of the unnecessary mutex in the ipmi_bmc_sim device. BTW, I haven't figured out a way to test this. Halting qemu doesn't seem to result in unrealizing anything, and none of the devices here can be hotplugged, so you can't delete them in the emulator. -corey
