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

Tony Krowiak
2018-11-06T20:21:14Z

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 <pmorel@linux.ibm.com>
> Signed-off-by: Michael Mueller <mimu@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;
> }
>
>