Appears that this was already done in 2018 October:
https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg05734.html
Disregard this thread, I should have searched better.
On Wed, Mar 27, 2019 at 4:02 PM Hikmat Jafarli wrote:
> So I'm trying to add IPv6 support to hostfwd, as requested in
> https://bugs.launchpad.net/qemu/+bug/1724590
>
> I'm not entirely sure what would be the right parameter format in case of
> IPv6 support.
>
> Current IPv4-only format is
> "hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport", example
> usage: "qemu-system-i386 -nic user,hostfwd=tcp:127.0.0.1:6001-:6000".
>
> I have searched through the manpages but couldn't find any other QEMU
> option of the same "kind" that also supported IPv6, so there's nothing to
> copy. What would be the right approach here? Should I introduce "hostfwd6"
> to be used separately or should I somehow extend the current "hostfwd"
> format?
>
> Any suggestions?
>
>
