On 2020/7/10 下午7:31, 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: stable@vger.kernel.org Signed-off-by: Michael S. Tsirkin mst@redhat.com
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
Acked-by: Jason Wang jasowang@redhat.com