The pnv_lpc_do_eccb function in hw/ppc/pnv_lpc.c in Qemu before 3.1 allows out-of-bounds write or read access to PowerNV memory.
http://lists.opensuse.org/opensuse-security-announce/2019-03/msg00042.html
https://lists.gnu.org/archive/html/qemu-devel/2018-11/msg00446.html
https://seclists.org/bugtraq/2019/May/76
https://usn.ubuntu.com/3826-1/