Re: QEMU 32-bit vs. 64-bit binaries

[Peter Maydell]

On Tue, 10 May 2022 at 13:21, Gerd Hoffmann <kraxel@redhat.com> wrote:
>
>   Hi,
>
> > I'm not very familiar with KVM on ARM - but is it possible to use KVM there
> > with an arbitrary machine? If that's the case, a user might want to use KVM
> > on their 64-bit host to run a 32-bit guest machine, and then you need to
> > keep the 32-bit machines in the -aarch64 binary.
>
> 32-bit guest is 'qemu-system-aarch64 -machine virt -cpu host,aarch64=off'
> (and a aarch64 CPU which actually supports the armv7 instructions).

It's still armv8 even when it's 32-bit :-) The requirement is AArch32
support at EL1. (Some hardware has AArch32 support at EL0 only,
ie userspace but not kernel, which obviously isn't enough for 32-bit
KVM guests.)

-- PMM