s390: vfio-ap: tighten the NIB validity check

The NIB is architecturally invalid if the address designates a
storage location that is not installed or if it is zero.

Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Reported-by: Janosch Frank <frankja@linux.ibm.com>
Fixes: ec89b55e3bce ("s390: ap: implement PAPQ AQIC interception in kernel")
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index cd488639a15b32824e1857e2bf4d6966a66e8dc4..28a36e016ea9105aca425ab6e176ffbb07051a02 100644 (file)
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -352,6 +352,8 @@ static int vfio_ap_validate_nib(struct kvm_vcpu *vcpu, dma_addr_t *nib)
 {
        *nib = vcpu->run->s.regs.gprs[2];
 
+       if (!*nib)
+               return -EINVAL;
        if (kvm_is_error_hva(gfn_to_hva(vcpu->kvm, *nib >> PAGE_SHIFT)))
                return -EINVAL;