On Fri, 27 Jul 2018 17:29:07 +0200
Thomas Huth <thuth@xxxxxxxxxx> wrote:
> 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)
Agreed, that pr_warn should be dropped. FWIW, the other vfio drivers
don't do this, either.
>
> > + 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);
> > +}
