On Tue, Jan 28, 2025 at 09:02:48AM +0000, Alex Bennée wrote: > Thomas Huth <th...@redhat.com> writes: > > > On 28/01/2025 01.42, Richard Henderson wrote: > >> Time for our biennial attempt to kill ancient hosts. > >> I've been re-working the tcg code generator a bit over the holidays. > >> One place that screams for a bit of cleanup is with 64-bit guest > >> addresses on 32-bit hosts. Of course the best "cleanup" is to not > >> have to handle such silliness at all. > >> Two years after Thomas' last attempt, > >> > >> https://lore.kernel.org/qemu-devel/20230130114428.1297295-1-th...@redhat.com/ > >> which resulted only in deprecation of i686 host for system > >> emulation. > >> By itself, this just isn't enough for large-scale cleanups. > >> I'll note that we've separately deprecated mips32, set to expire > >> with the end of Debian bookworm, set to enter LTS in June 2026. > >> I'll note that there is *already* no Debian support for ppc32, > >> and that I am currently unable to cross-compile that host at all. > > > > IIRC the biggest pushback that I got two years ago was with regards to > > 32-bit arm: The recommended version of Raspberry Pi OS is still > > 32-bit: > > > > > > https://lore.kernel.org/qemu-devel/f852c238-77b8-4e24-9494-8d060eb78...@livius.net/ > > > > And looking at https://www.raspberrypi.com/software/operating-systems/ > > this still seems to be the case... > > > > So I guess the main question is now: Would it be ok to kill support > > for 32-bit Raspberry Pi OS nowadays? > > I would argue yes for a few reasons. > > - you can't buy 32 bit only Pi's AFAICT, even the Pi Zero 2W can work > with a 64 bit OS. > > - It's not like the versions shipping in bullseye and bookworm will > stop working. > > - Even if we deprecate now there will likely be one more Debian > release cycle that gets 32 bit host support. > > >> Showing my hand a bit, I am willing to limit deprecation to > >> 64-bit guests on 32-bit hosts. But I'd prefer to go the whole hog: > >> unconditional support for TCG_TYPE_I64 would remove a *lot* of > >> 32-bit fallback code. > > I support going the whole hog. I would be curious what use cases still > exist for an up to date 32-on-32 QEMU based emulation?
Last time we discussed this, we distinguished between system emulation and linux-user. I believe Richard is proposing to deprecated *both*, but lets call that out explicitly in any deprecation message to avoid mis-understandings. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
