You forgot to suppress the pvpanic device with the really old machine types using pc_init_pci_no_kvmclock().
$ for i in `qemu-system-x86_64 -M help | awk '/^[a-z]/ { print $1 }'| grep -v xen`; do echo -n $i; echo -e "info qtree\nq" | qemu-system-x86_64 -nodefaults -S -nographic -monitor stdio -M $i | grep pvpanic || echo; done pc dev: pvpanic, id "" pc-i440fx-1.5 dev: pvpanic, id "" pc-i440fx-1.4 pc-1.3 pc-1.2 pc-1.1 pc-1.0 pc-0.15 pc-0.14 pc-0.13 dev: pvpanic, id "" pc-0.12 dev: pvpanic, id "" pc-0.11 dev: pvpanic, id "" pc-0.10 dev: pvpanic, id "" isapc dev: pvpanic, id "" q35 dev: pvpanic, id "" pc-q35-1.5 dev: pvpanic, id "" pc-q35-1.4 Sorry I didn't catch this earlier.