Re: [PATCH v3 2/2] vfio/cdx: add interrupt support

[Gupta, Nipun]

On 3/1/2024 11:15 PM, Alex Williamson wrote:
> On Mon, 26 Feb 2024 14:18:13 +0530
> Nipun Gupta <nipun.gupta@xxxxxxx> wrote:
>
> > Support the following ioctls for CDX devices:
> > - VFIO_DEVICE_GET_IRQ_INFO
> > - VFIO_DEVICE_SET_IRQS
> >
> > This allows user to set an eventfd for cdx device interrupts and
> > trigger this interrupt eventfd from userspace.
> > All CDX device interrupts are MSIs. The MSIs are allocated from the
> > CDX-MSI domain.
> >
> > Signed-off-by: Nipun Gupta <nipun.gupta@xxxxxxx>
> > Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@xxxxxxx>
> > ---

<snip>

> > +static int vfio_cdx_ioctl_get_irq_info(struct vfio_cdx_device *vdev,
> > +				       struct vfio_irq_info __user *arg)
> > +{
> > +	unsigned long minsz = offsetofend(struct vfio_irq_info, count);
> > +	struct cdx_device *cdx_dev = to_cdx_device(vdev->vdev.dev);
> > +	struct vfio_irq_info info;
> > +
> > +	if (copy_from_user(&info, arg, minsz))
> > +		return -EFAULT;
> > +
> > +	if (info.argsz < minsz)
> > +		return -EINVAL;
> > +
> > +	if (info.index >= 1)
> > +		return -EINVAL;
> > +
> > +	info.flags = VFIO_IRQ_INFO_EVENTFD;
>
>
> I think the way you're using this you'd also need the
> VFIO_IRQ_INFO_NORESIZE to indicate the MSI range cannot be expanded
> from the initial setting.  Thanks,

Yes, agree. Will update the flags in the next spin.

Thanks,
Nipun

> Alex