Re: [PATCH 1/2] KVM: s390: rename PROT_NONE to PROT_TYPE_DUMMY

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

On Fri, May 16, 2025 at 11:39:19AM -0400, Liam R. Howlett wrote:
> * Lorenzo Stoakes <lorenzo.stoakes@oracle.com> [250515 16:15]:
> > The enum type prot_type declared in arch/s390/kvm/gaccess.c declares an
> > unfortunate identifier within it - PROT_NONE.
> >
> > This clashes with the protection bit define from the uapi for mmap()
> > declared in include/uapi/asm-generic/mman-common.h, which is indeed what
> > those casually reading this code would assume this to refer to.
> >
> > This means that any changes which subsequently alter headers in any way
> > which results in the uapi header being imported here will cause build
> > errors.
> >
> > Resolve the issue by renaming PROT_NONE to PROT_TYPE_DUMMY.
> >
> > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> > Suggested-by: Ignacio Moreno Gonzalez <Ignacio.MorenoGonzalez@kuka.com>
> > Fixes: b3cefd6bf16e ("KVM: s390: Pass initialized arg even if unused")
> > Cc: stable@vger.kernel.org
> > Reported-by: kernel test robot <lkp@intel.com>
> > Closes: https://lore.kernel.org/oe-kbuild-all/202505140943.IgHDa9s7-lkp@intel.com/
> > Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> > Acked-by: Ignacio Moreno Gonzalez <Ignacio.MorenoGonzalez@kuka.com>
> > Acked-by: Yang Shi <yang@os.amperecomputing.com>
> > Reviewed-by: David Hildenbrand <david@redhat.com>
>
> Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com>

Thanks!

>
> > ---
> >  arch/s390/kvm/gaccess.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
> > index f6fded15633a..4e5654ad1604 100644
> > --- a/arch/s390/kvm/gaccess.c
> > +++ b/arch/s390/kvm/gaccess.c
> > @@ -318,7 +318,7 @@ enum prot_type {
> >  	PROT_TYPE_DAT  = 3,
> >  	PROT_TYPE_IEP  = 4,
> >  	/* Dummy value for passing an initialized value when code != PGM_PROTECTION */
> > -	PROT_NONE,
> > +	PROT_TYPE_DUMMY,
> >  };
> >
> >  static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar,
> > @@ -334,7 +334,7 @@ static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva,
> >  	switch (code) {
> >  	case PGM_PROTECTION:
> >  		switch (prot) {
> > -		case PROT_NONE:
> > +		case PROT_TYPE_DUMMY:
> >  			/* We should never get here, acts like termination */
> >  			WARN_ON_ONCE(1);
> >  			break;
> > @@ -804,7 +804,7 @@ static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
> >  			gpa = kvm_s390_real_to_abs(vcpu, ga);
> >  			if (!kvm_is_gpa_in_memslot(vcpu->kvm, gpa)) {
> >  				rc = PGM_ADDRESSING;
> > -				prot = PROT_NONE;
> > +				prot = PROT_TYPE_DUMMY;
> >  			}
> >  		}
> >  		if (rc)
> > @@ -962,7 +962,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
> >  		if (rc == PGM_PROTECTION)
> >  			prot = PROT_TYPE_KEYC;
> >  		else
> > -			prot = PROT_NONE;
> > +			prot = PROT_TYPE_DUMMY;
> >  		rc = trans_exc_ending(vcpu, rc, ga, ar, mode, prot, terminate);
> >  	}
> >  out_unlock:
> > --
> > 2.49.0
> >