Re: [PATCH v2 1/3] KVM: s390: Toggle operation exception for userspace

[Eric Farman <farman@linux.ibm.com>]

On Mon, 2026-05-11 at 10:08 +0200, Janosch Frank wrote:
> On 5/7/26 22:08, Eric Farman wrote:
> > The KVM_CAP_S390_USER_OPEREXEC capability allows operation exceptions
> > to be forwarded to userspace. But the actual enablement at the hardware
> > level occurs in kvm_arch_vcpu_postcreate(), and only if STFLE.74 or
> > user_instr0 are enabled. The latter is associated with a separate
> > capability (KVM_CAP_S390_USER_INSTR0), so the only way this happens
> > for the USER_OPEREXEC capability is if STFLE.74 is enabled. KVM
> > unconditionally enables this bit in kvm_arch_init_vm(), but the guest
> > could disable it from the CPU model and thus ignore this capability.
> > 
> > Add USER_OPEREXEC to the check in kvm_arch_vcpu_postcreate(), such that
> > either capability would enable this type of exception.
> > 
> 
> Naming wise shouldn't this be something like:
> KVM: s390: Fix S390_USER_OPEREXEC enablement without stfle 74
> 
> ?

Yeah, that is clearer, and I would be fine with that edit.