Re: [PATCH v7 11/23] KVM: arm64: Share arm64 code with s390

On Sat, Sep 12, 2026 at 12:43:28PM +0100, Marc Zyngier wrote:

On Wed, 02 Sep 2026 13:41:52 +0100,
Steffen Eiden [off-list ref] wrote:

[...]

quoted

So my suggestion is:

For series 1 (and 2) s390 has its own, local implementation of
handle_exit without sharing any code with arm64 in regard to EC

When s390 has all the relevant code available (likely series 3) s390 can
switch to using most (if not all) EC handling code used by
arm_exit_handlers implemented in handle_exit.c.

This can be done without a mixed patch:

1. Mark arm64 handle_exit.c as shared (roughly the first 400Loc w/o
   includes) - s390 will not use it after this patch.
2. remove the handle exit code from s390's handle_exit.c and include the
   new generated handle_exit.inc

This approach brings us further into the share architecture not only code
approach you meantrioned in the comments regarding sys-regs. (I or
Andreas will provide a solution for this later :) ) 

Is that OK with you, what do you think?

I *think* that's OK. I just want to make sure that in the long run, we
don't end-up with pointless divergence.

Yes, that is what I want to avoid as well. I want like to share as much
architecture code/concepts as possible while keeping the churn as low as
possible.

	Steffen