Re: [PATCH 1/2] docs/about: Deprecate 32-bit x86 hosts and qemu-system-i386
On 27/2/23 21:12, Michael S. Tsirkin wrote:
On Mon, Feb 27, 2023 at 11:50:07AM +0000, Daniel P. Berrangé wrote:
> I feel like we should have separate deprecation entries for the
> i686 host support, and for qemu-system-i386 emulator binary, as
> although they're related they are independant features with
> differing impact. eg removing qemu-system-i386 affects all
> host architectures, not merely 32-bit x86 host, so I think we
> can explain the impact more clearly if we separate them.
Removing qemu-system-i386 seems ok to me - I think qemu-system-x86_64 is
a superset.
Doesn't qemu-system-i386 start the CPU in a different mode that
qemu-system-x86_64? Last time we discussed it, we mention adding
-32 and -64 CLI flags to maintain compat, and IIRC this flag would
add boot code to switch the CPU in 32-b. But then maybe I misunderstood.
Thomas said, "CPUs must start in the same mode they start in HW".
Removing support for building on 32 bit systems seems like a pity -
it's
one of a small number of ways to run 64 bit binaries on 32 bit systems,
and the maintainance overhead is quite small.
In fact, keeping this support around forces correct use of
posix APIs such as e.g. PRIx64 which makes the code base
more future-proof.