/usr/share/qemu/acpi-dsdt.aml is in qemu-system-x86 2.0.0~rc1+dfsg-0ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/qemu/../seabios/acpi-dsdt.aml
/usr/share/qemu/../seabios/acpi-dsdt.aml