On Wed, 18 Oct 2023 09:38:24 -0400 Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote: > From: Anthony Krowiak <akrowiak@xxxxxxxxxxxxx> > > The interception handler for the PQAP(AQIC) command calls the > kvm_s390_gisc_register function to register the guest ISC with the channel > subsystem. If that call fails, the status response code 08 - indicating > Invalid ZONE/GISA designation - is returned to the guest. This response > code does not make sense because the non-zero return code from the > kvm_s390_gisc_register function can be due one of two things: Either the > ISC passed as a parameter by the guest to the PQAP(AQIC) command is greater > than the maximum ISC value allowed, or the guest is not using a GISA. The "ISC passed as a parameter by the guest to the PQAP(AQIC) command is greater than the maximum ISC value allowed" is not possible. The isc is 3 bits wide and all 8 values that can be represented on 3 bits are valid. This is only possible if the hypervisor was to mess up, or if the machine was broken. > > Since this scenario is very unlikely to happen and there is no status > response code to indicate an invalid ISC value, let's set the > response code to 06 indicating 'Invalid address of AP-queue notification > byte'. While this is not entirely accurate, it is better than indicating > that the ZONE/GISA designation is invalid which is something the guest > can do nothing about since those values are set by the hypervisor. > > Signed-off-by: Anthony Krowiak <akrowiak@xxxxxxxxxxxxx> > Suggested-by: Halil Pasic <pasic@xxxxxxxxxxxxx> > --- > drivers/s390/crypto/vfio_ap_ops.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > index 9cb28978c186..25d7ce2094f8 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -393,8 +393,8 @@ static int ensure_nib_shared(unsigned long addr, struct gmap *gmap) > * Register the guest ISC to GIB interface and retrieve the > * host ISC to issue the host side PQAP/AQIC > * > - * Response.status may be set to AP_RESPONSE_INVALID_ADDRESS in case the > - * vfio_pin_pages failed. > + * status.response_code may be set to AP_RESPONSE_INVALID_ADDRESS in case the > + * vfio_pin_pages or kvm_s390_gisc_register failed. > * > * Otherwise return the ap_queue_status returned by the ap_aqic(), > * all retry handling will be done by the guest. > @@ -458,7 +458,7 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q, > __func__, nisc, isc, q->apqn); > > vfio_unpin_pages(&q->matrix_mdev->vdev, nib, 1); > - status.response_code = AP_RESPONSE_INVALID_GISA; > + status.response_code = AP_RESPONSE_INVALID_ADDRESS; > return status; > } >
