On 07/26/2018 09:54 PM, Christian Borntraeger wrote:
> From: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
>
> Introduces ioctl access to the VFIO AP Matrix device driver
> by implementing the VFIO_DEVICE_GET_INFO ioctl. This ioctl
> provides the VFIO AP Matrix device driver information to the
> guest machine.
>
> Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
> Reviewed-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> Acked-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
> Tested-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
> Tested-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
> Tested-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> ---
> drivers/s390/crypto/vfio_ap_ops.c | 43 +++++++++++++++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index d06067a23000..01c429cb51d5 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -867,6 +867,48 @@ static void vfio_ap_mdev_release(struct mdev_device *mdev)
> module_put(THIS_MODULE);
> }
>
> +static int vfio_ap_mdev_get_device_info(unsigned long arg)
> +{
> + unsigned long minsz;
> + struct vfio_device_info info;
> +
> + minsz = offsetofend(struct vfio_device_info, num_irqs);
> +
> + if (copy_from_user(&info, (void __user *)arg, minsz))
> + return -EFAULT;
> +
> + if (info.argsz < minsz) {
> + pr_warn("%s: Argument size %u less than min size %li\n",
> + VFIO_AP_MODULE_NAME, info.argsz, minsz);
Do you really need this pr_warn here? The -EINVAL should give a clear
indication about the problem already. (and in the worst case, a
malicious userspace program could use it to flood the kernel log)
> + return -EINVAL;
> + }
> +
> + info.flags = VFIO_DEVICE_FLAGS_AP;
> + info.num_regions = 0;
> + info.num_irqs = 0;
> +
> + return copy_to_user((void __user *)arg, &info, minsz);
> +}
> +
> +static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,
> + unsigned int cmd, unsigned long arg)
> +{
> + int ret;
> +
> + switch (cmd) {
> + case VFIO_DEVICE_GET_INFO:
> + ret = vfio_ap_mdev_get_device_info(arg);
> + break;
> + default:
> + pr_warn("%s: ioctl command %d is not a supported command\n",
> + VFIO_AP_MODULE_NAME, cmd);
I'd also remove this pr_warn - the -EOPNOTSUPP should be enough.
> + ret = -EOPNOTSUPP;
> + break;
"break;" is also not required here.
> + }
> +
> + return ret;
> +}
> +
> static const struct mdev_parent_ops vfio_ap_matrix_ops = {
> .owner = THIS_MODULE,
> .supported_type_groups = vfio_ap_mdev_type_groups,
> @@ -875,6 +917,7 @@ static const struct mdev_parent_ops vfio_ap_matrix_ops = {
> .remove = vfio_ap_mdev_remove,
> .open = vfio_ap_mdev_open,
> .release = vfio_ap_mdev_release,
> + .ioctl = vfio_ap_mdev_ioctl,
> };
>
> int vfio_ap_mdev_register(void)
>
Thomas
