Re: [PATCH v1 6/7] vfio: ap: register guest ISC with GISA and GIB

[Tony Krowiak]

On 10/31/18 2:12 PM, Pierre Morel wrote:

Register to the GIB Alert list and retrieve the GAL_ISC
to pass to the GISA registration.

Unregister on error and when clearing the interrupt.

Signed-off-by: Pierre Morel <pmo...@linux.ibm.com>
Signed-off-by: Michael Mueller <m...@linux.ibm.com>
---
  drivers/s390/crypto/vfio_ap_ops.c | 16 +++++++++++++---
  1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c 
b/drivers/s390/crypto/vfio_ap_ops.c
index f68102163bf4..232168797fb8 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -903,16 +903,20 @@ static int ap_ioctl_setirq(struct ap_matrix_mdev 
*matrix_mdev,
        struct ap_status ap_status = reg2status(0);
        unsigned long p;
        int ret = -1;
-       int apqn;
+       int apqn, gal_isc;
        uint32_t gd;

+ gal_isc = kvm_s390_gisc_register(matrix_mdev->kvm, matrix_mdev->gisc);

+       if (gal_isc < 0)
+               return -EIO;
+
        apqn = (int)(parm->cmd & 0xffff);

gd = matrix_mdev->kvm->vcpus[0]->arch.sie_block->gd;

        if (gd & 0x01)
                aqic_gisa.f = 1;
        aqic_gisa.gisc = matrix_mdev->gisc;
-       aqic_gisa.isc = GAL_ISC;
+       aqic_gisa.isc = gal_isc;
        aqic_gisa.ir = 1;
        aqic_gisa.gisao = gisa->next_alert >> 4;

@@ -923,7 +927,11 @@ static int ap_ioctl_setirq(struct ap_matrix_mdev *matrix_mdev,

        parm->status = ret;

ap_status = reg2status(ret);

-       return (ap_status.rc) ? -EIO : 0;
+       if (ap_status.rc) {
+               kvm_s390_gisc_unregister(matrix_mdev->kvm, matrix_mdev->gisc);
+               return -EIO;
+       }
+       return 0;
  }

static int ap_ioctl_clrirq(struct ap_matrix_mdev *matrix_mdev,

@@ -946,6 +954,8 @@ static int ap_ioctl_clrirq(struct ap_matrix_mdev 
*matrix_mdev,
        parm->status = retval;

ap_status = reg2status(retval);

+       /* unregister the IAM from the GIB anyway! */
+       kvm_s390_gisc_unregister(matrix_mdev->kvm, matrix_mdev->gisc);

The case statement in patch 4 does not set mdev->gisc, so the
presumption here is that VFIO_AP_SET_IRQ has been previously called and
has set the value for matrix_mdev->gisc. Is it possible for
VFIO_AP_CLEAR_IRQ to get invoked without a prior call to
VFIO_AP_SET_IRQ? In any case, shouldn't the GISC value be taken from
bits 61-63 of 'parm'?

        return (ap_status.rc) ? -EIO : 0;
  }