Re: [PATCH v7 02/23] KVM: Make device name configurable

[Sean Christopherson <seanjc@google.com>]

On Thu, Sep 03, 2026, Steffen Eiden wrote:
> On Wed, Sep 02, 2026 at 09:14:21AM -0700, Sean Christopherson wrote:
> > On Wed, Sep 02, 2026, Steffen Eiden wrote:
> > > On Tue, Sep 01, 2026 at 05:40:25PM -0700, Sean Christopherson wrote:
> > > > On Mon, Aug 31, 2026, Steffen Eiden wrote:
> > > > > Allow KVM implementations to choose alternative device names. This is
> > > > > especially useful for architectures providing multiple KVM
> > > > > implementations simultaneously. Architectures providing multiple KVM
> > > > > implementations must compile the KVM common code once per
> > > > > implementation and mange symbols.
> > > > 
> > > > What about tracepoints?  Or do those show up as "kvm" and "kvm-arm64"?
> > > 
> > > Yes, I want them to show up as kvm and  kvm-arm64.
> > > 
> > > Thanks for pointing that out - I just noticed that I forgot to switch
> > > the trace system to kvm-arm64 for the common tracepoints in
> > > trace/events/kvm.h
> > > I only did it for the arch-local traces in PATCH 21.
> > > 
> > > I would just do the following:
> > > 
> > > diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h
> > > index b282e3a86769..5d4f8a0693a3 100644
> > > --- a/include/trace/events/kvm.h
> > > +++ b/include/trace/events/kvm.h
> > > @@ -5,7 +5,11 @@
> > >  #include <linux/tracepoint.h>
> > > 
> > >  #undef TRACE_SYSTEM
> > > +#ifdef KVM_S390_ARM64
> > 
> > Side topic, I recommend choosing a macro name that doesn't have a near-collision
> > with CONFIG_KVM_S390_ARM64.  This *looks* like a typo, i.e. it looks like you
> > forgot the CONFIG_ prefix.  Especially since the macro is defined in the Makefile
> > and won't show up with e.g. "git grep -w KVM_S390_ARM64". E.g. KVM_S390_BUILD_ARM64
> > or something?
> 
> Interesting. The name was deliberately chosen to be similar. But I
> see that it could be confusing.
> 
> I am not totally happy with KVM_S390_BUILD_ARM64 but I cannot find a
> better name either.

Y'all need to pick *one* method.  KVM_S390_MANAGES_S390_GUEST was already added
by a07276d5d188 ("KVM: s390: gmap: Make storage keys optional"), and then this
series effectively adds another macro to provide the inversion of that, except
they're not even tied together.