s390: vsie: Use effective CRYCBD.31 to check CRYCBD validity

When facility.76 MSAX3 is present for the guest we must issue a validity
interception if the CRYCBD is not valid.

The bit CRYCBD.31 is an effective field and tested at each guest level
and has for effect to mask the facility.76

It follows that if CRYCBD.31 is clear and AP is not in use  we do not
have to test the CRYCBD validatity even if facility.76 is present in the
host.

Fixes: 6ee74098201b ("KVM: s390: vsie: allow CRYCB FORMAT-0")
Cc: stable@vger.kernel.org
Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reported-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <1549876849-32680-1-git-send-email-pmorel@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index a153257bf7d9877a10ea0f857b8985bb798f3003..d62fa148558b99dccab51d3cdf8ea3cef06e31fa 100644 (file)
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -297,7 +297,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
        scb_s->crycbd = 0;
 
        apie_h = vcpu->arch.sie_block->eca & ECA_APIE;
-       if (!apie_h && !key_msk)
+       if (!apie_h && (!key_msk || fmt_o == CRYCB_FORMAT0))
                return 0;
 
        if (!crycb_addr)