Re: [PATCH v1 4/7] vfio: ap: AP Queue Interrupt Control VFIO ioctl calls

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 31 Oct 2018 19:12:54 +0100
Pierre Morel <pmorel@linux.ibm.com> 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@linux.ibm.com>
> ---
>  drivers/s390/crypto/vfio_ap_ops.c | 95 +++++++++++++++++++++++++++++++
>  1 file changed, 95 insertions(+)
> 
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 272ef427dcc0..f68102163bf4 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -895,12 +895,107 @@ static int vfio_ap_mdev_get_device_info(unsigned long arg)
>  	return copy_to_user((void __user *)arg, &info, minsz);
>  }
>  
> +static int ap_ioctl_setirq(struct ap_matrix_mdev *matrix_mdev,
> +			   struct vfio_ap_aqic *parm)
> +{
> +	struct aqic_gisa aqic_gisa = reg2aqic(0);
> +	struct kvm_s390_gisa *gisa = matrix_mdev->kvm->arch.gisa;
> +	struct ap_status ap_status = reg2status(0);
> +	unsigned long p;
> +	int ret = -1;
> +	int apqn;
> +	uint32_t gd;
> +
> +	apqn = (int)(parm->cmd & 0xffff);

It seems you always use cmd & 0xffff only. What if there is other stuff
in the remaining bits of cmd? Do you plan to ignore it in any case, or
should you actively check that there is nothing in it?