<os>
<acpi>
<table type="slic">/path/to/acpi/table/file</table>
</acpi>
</os>
will result in:
-acpitable sig=SLIC,file=/path/to/acpi/table/file
This option was introduced by QEMU commit 8a92ea2 in 2009.
https://bugzilla.redhat.com/show_bug.cgi?id=1327537