* Peter Maydell (peter.mayd...@linaro.org) wrote: > On Tue, 10 May 2022 at 10:01, Thomas Huth <th...@redhat.com> wrote: > > > > On 10/05/2022 10.54, Markus Armbruster wrote: > > > Thomas Huth <th...@redhat.com> writes: > > > > > > [...] > > > > > >> I once suggested in the past already that we should maybe get rid of > > >> the 32-bit variants in case the 64-bit variant is a full superset, so > > >> we can save compile- and test times (which is quite a bit for QEMU), > > >> but I've been told that the 32-bit variants are mostly still required > > >> for supporting KVM on 32-bit host machines. > > > > > > Do we still care for 32-bit host machines? > > > > As long as the Linux kernel still supports 32-bit KVM virtualization, I > > think we have to keep the userspace around for that, too. > > > > But I wonder why we're keeping qemu-system-arm around? 32-bit KVM support > > for ARM has been removed with Linux kernel 5.7 as far as I know, so I think > > we could likely drop the qemu-system-arm nowadays, too? Peter, Richard, > > what's your opinion on this? > > Two main reasons, I think: > * command-line compatibility (ie there are lots of > command lines out there using that binary name) > * nobody has yet cared enough to come up with a plan for what > we want to do differently for these 32-bit architectures, > so the default is "keep doing what we always have" > > In particular, I don't want to get rid of qemu-system-arm as the > *only* 32-bit target binary we drop. Either we stick with what > we have or we have a larger plan for sorting this out consistently > across target architectures.
To my mind, qemu-system-arm makes a lot of sense, and I'd rather see the 32 bit guests disappear from qemu-system-aarch64. It's difficult to justify to someone running their aarch virt stack why their binary has the security footprint that includes a camera or PDA. ARM is a lot cleaner than x86; you don't suddenly find a little Cortex-M machine with a big 64 bit core in it; yet on x86 our machines are frankenstinian mixes with 25 year old chipsets and modern CPUs. Dave > -- PMM > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
