It's good to have a Hangover

One of the wishlists for us OpenPOWER workstation users is better emulation for when we have to run an application that only comes as a Windows binary. QEMU is not too quick, largely because of its overhead, and although Bochs is faster in some respects it's worse in others and doesn't have a JIT. While things like HQEMU are fast, they also have their own unique problems, and many things that work in QEMU don't work in HQEMU. Unfortunately, because Wine Is Not an Emulator, it cannot be used to run Windows binaries directly.

People then ask the question, what if we somehow put QEMU and Wine together like Slaughterhouse-Five and see if they breed? Somebody did that, at least for aarch64, and that is Hangover. And now it runs on ppc64le with material support for testing provided by Raptor.

Hangover is unabashedly imperfect and many things still don't work, and there are probably things that work on aarch64 that don't work on ppc64le as the support is specifically advertised as "incomplete." (Big-endian need not apply, by the way: there are no thunks here for converting endianness. Sorry.) There is also the maintainability problem that the changes to Wine to support ppc64le (done by Raptor themselves, as we understand) haven't been upstreamed and that will contribute to the rebasing burden.

With all that in mind, how's it work? Well ... I have no idea, because the other problem is right now it's limited to kernels using a 4K page size and not every ppc64le-compatible distribution uses them. Void Linux, for example, does support 4K pages on ppc64le, but Fedora only officially supports a 64K page size, and I'm typing this on Fedora 32. It may be possible to hack Hangover to add this support but the maintainer ominously warns that "loading PE binaries, which have 4K aligned sections, into a 64K page comes with [lots] of problems, so currently the best approach is to avoid that." I'm rebuilding my Blackbird system but I like using it as a Fedora tester before running upgrades on this daily driver Talos II, which has saved me some substantial inconvenience in the past. That said, a live CD that boots Void and then runs Hangover might be fun to work on.

If you've built Hangover on your machine and given it a spin, advise how well it works for you and how it compares to QEMU in the comments.