Comment 9 for bug 1902654

$ gdb /usr/bin/qemu-system-x86_64
(gdb) run -m 128 -M pc-i440fx-wily,accel=kvm --nodefaults --nographic --monitor stdio -device virtio-balloon-pci,id=balloon0
(gdb) handle SIGUSR1 noprint nostop

/*
 * Global property defaults
 * Slot 0: accelerator's global property defaults
 * Slot 1: machine's global property defaults
 * Each is a GPtrArray of of GlobalProperty.
 * Applied in order, later entries override earlier ones.
 */
static GPtrArray *object_compat_props[2];

^^^ this is where the compat data lands on init with a wily type machine.

Thread 1 "qemu-system-x86" hit Breakpoint 1, qemu_init_main_loop (errp=0x7fffffffe468) at ./util/main-loop.c:148
148 {
(gdb) p (*(GlobalProperty*)(object_compat_props[1]).pdata[139])
$17 = {driver = 0x555555ea725c "virtio-balloon-pci", property = 0x555555ea2c91 "any_layout", value = 0x555555ee6853 "off", used = false, optional = false}

So it got into the type correctly.