vfio/fsl-mc: Implement VFIO_DEVICE_GET_INFO ioctl

Allow userspace to get fsl-mc device info (number of regions
and irqs).
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/fsl-mc/vfio_fsl_mc.c

@@ -33,10 +33,29 @@ static void vfio_fsl_mc_release(void *device_data)
 static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
 			      unsigned long arg)
 {
+	unsigned long minsz;
+	struct vfio_fsl_mc_device *vdev = device_data;
+	struct fsl_mc_device *mc_dev = vdev->mc_dev;
+
 	switch (cmd) {
 	case VFIO_DEVICE_GET_INFO:
 	{
-		return -ENOTTY;
+		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)
+			return -EINVAL;
+
+		info.flags = VFIO_DEVICE_FLAGS_FSL_MC;
+		info.num_regions = mc_dev->obj_desc.region_count;
+		info.num_irqs = mc_dev->obj_desc.irq_count;
+
+		return copy_to_user((void __user *)arg, &info, minsz) ?
+			-EFAULT : 0;
 	}
 	case VFIO_DEVICE_GET_REGION_INFO:
 	{