On 10.07.20 13:31, Michael S. Tsirkin wrote: > Page reporting features were never supported by legacy hypervisors. > Supporting them poses a problem: should we use native endian-ness (like > current code assumes)? Or little endian-ness like the virtio spec says? > Rather than try to figure out, and since results of > incorrect endian-ness are dire, let's just block this configuration. > > Cc: [email protected] > Signed-off-by: Michael S. Tsirkin <[email protected]> > --- > drivers/virtio/virtio_balloon.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 5d4b891bf84f..b9bc03345157 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -1107,6 +1107,15 @@ static int virtballoon_restore(struct virtio_device > *vdev) > > static int virtballoon_validate(struct virtio_device *vdev) > { > + /* > + * Legacy devices never specified how modern features should behave. > + * E.g. which endian-ness to use? Better not to assume anything. > + */ > + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) { > + __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT); > + __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_PAGE_POISON); > + __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_REPORTING); > + } > /* > * Inform the hypervisor that our pages are poisoned or > * initialized. If we cannot do that then we should disable >
Very right Acked-by: David Hildenbrand <[email protected]> -- Thanks, David / dhildenb _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
