Re: [PATCH] virtio_balloon: disable VIOMMU support

[Jason Wang <jasowang@redhat.com>]

On 2017年06月14日 02:00, Michael S. Tsirkin wrote:
> virtio balloon bypasses the DMA API entirely so does not support the
> VIOMMU right now.  It's not clear we need that support, for now let's
> just make sure we don't pretend to support it.
>
> Cc: stable@vger.kernel.org
> Cc: Wei Wang <wei.w.wang@intel.com>
> Fixes: 1a937693993f ("virtio: new feature to detect IOMMU device quirk")
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>   drivers/virtio/virtio_balloon.c | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index 408c174..22caf80 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -663,6 +663,12 @@ static int virtballoon_restore(struct virtio_device *vdev)
>   }
>   #endif
>   
> +static int virtballoon_validate(struct virtio_device *vdev)
> +{
> +	__virtio_clear_bit(vdev, VIRTIO_F_IOMMU_PLATFORM);
> +	return 0;
> +}
> +
>   static unsigned int features[] = {
>   	VIRTIO_BALLOON_F_MUST_TELL_HOST,
>   	VIRTIO_BALLOON_F_STATS_VQ,
> @@ -675,6 +681,7 @@ static struct virtio_driver virtio_balloon_driver = {
>   	.driver.name =	KBUILD_MODNAME,
>   	.driver.owner =	THIS_MODULE,
>   	.id_table =	id_table,
> +	.validate =	virtballoon_validate,
>   	.probe =	virtballoon_probe,
>   	.remove =	virtballoon_remove,
>   	.config_changed = virtballoon_changed,

Acked-by: Jason Wang <jasowang@redhat.com>