Re: [PATCH v2 3/3] vfio: ap: AP Queue Interrupt Control VFIO ioctl calls

From: Cornelia Huck
Date: Mon Dec 03 2018 - 05:04:36 EST


On Thu, 22 Nov 2018 18:11:15 +0100
Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:

> This is the implementation of the VFIO ioctl calls to handle
> the AQIC interception and use GISA to handle interrupts.
>
> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> ---
> drivers/s390/crypto/vfio_ap_ops.c | 110 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 109 insertions(+), 1 deletion(-)
>

> +static int vfio_ap_ioctl_setirq(struct mdev_device *mdev, unsigned long arg)
> +{
> + struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct vfio_ap_aqic parm;
> + struct ap_qirq_ctrl aqic_gisa = {};
> + struct kvm *kvm = matrix_mdev->kvm;
> + struct kvm_s390_gisa *gisa = kvm->arch.gisa;
> + struct ap_queue_status ap_status;
> + unsigned long nib;
> +
> + if (copy_from_user(&parm, (void __user *)arg, sizeof(parm)))
> + return -EFAULT;
> +
> + if (parm.isc > MAX_ISC)
> + return -EINVAL;
> +
> + if (kvm->vcpus[0]->arch.sie_block->gd & 0x01)
> + aqic_gisa.gf = 1;
> +
> + nib = vfio_ap_get_nib(kvm, &parm);
> + if (!nib)
> + return -ENODEV;
> +
> + aqic_gisa.gisc = parm.isc;
> + aqic_gisa.isc = kvm_s390_gisc_register(kvm, parm.isc);

Oh, and as I just looked at the callers of these functions: You'll want
to check the return code here, even though the function should not fail
with the checking you did beforehand.

[I assume you'll have similar code even when using a different
interface.]

> + aqic_gisa.ir = 1;
> + aqic_gisa.gisa = gisa->next_alert >> 4;
> +
> + ap_status = ap_aqic(parm.apqn, aqic_gisa, (void *)nib);
> + parm.status = *(uint32_t *)(&ap_status);
> +
> + if (copy_to_user((void __user *)arg, &parm, sizeof(parm))) {
> + kvm_s390_gisc_unregister(kvm, parm.isc);
> + return -EFAULT;
> + }
> +
> + if (ap_status.response_code) {
> + kvm_s390_gisc_unregister(kvm, parm.isc);
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +static int vfio_ap_ioctl_clrirq(struct mdev_device *mdev, unsigned long arg)
> +{
> + struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct vfio_ap_aqic parm;
> + struct ap_qirq_ctrl aqic_gisa = {};
> + struct ap_queue_status ap_status;
> + struct kvm *kvm = matrix_mdev->kvm;
> +
> + if (copy_from_user(&parm, (void __user *)arg, sizeof(parm)))
> + return -EFAULT;
> +
> + if (kvm->vcpus[0]->arch.sie_block->gd & 0x01)
> + aqic_gisa.gf = 1;
> + aqic_gisa.ir = 0;
> +
> + ap_status = ap_aqic(parm.apqn, aqic_gisa, NULL);
> + parm.status = *(uint32_t *)(&ap_status);
> +
> + kvm_s390_gisc_unregister(kvm, parm.isc);

Here, you don't seem to verify the sanity of parm.isc beforehand...
luckily the function can deal with that :)

> +
> + if (copy_to_user((void __user *)arg, &parm, sizeof(parm)))
> + return -EFAULT;
> +
> + return (ap_status.response_code) ? -EIO : 0;
> +}
> +