Use the extended feature type for 'acked_features' and implement
two new ioctls operation to get and set the extended features.

Note that the legacy ioctls implicitly truncate the negotiated
features to the lower 64 bits range.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 drivers/vhost/net.c        | 26 +++++++++++++++++++++++++-
 drivers/vhost/vhost.h      |  2 +-
 include/uapi/linux/vhost.h |  8 ++++++++
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 7cbfc7d718b3f..b894685dded3e 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c

@@ -77,6 +77,10 @@ enum {
                         (1ULL << VIRTIO_F_RING_RESET)
 };

+#ifdef VIRTIO_HAS_EXTENDED_FEATURES
+#define VHOST_NET_FEATURES_EX VHOST_NET_FEATURES
+#endif
+
 enum {
        VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
 };

@@ -1614,7 +1618,7 @@ static long vhost_net_reset_owner(struct vhost_net *n)
        return err;
 }

-static int vhost_net_set_features(struct vhost_net *n, u64 features)
+static int vhost_net_set_features(struct vhost_net *n, virtio_features_t features)
 {
        size_t vhost_hlen, sock_hlen, hdr_len;
        int i;

@@ -1704,6 +1708,26 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
                if (features & ~VHOST_NET_FEATURES)
                        return -EOPNOTSUPP;
                return vhost_net_set_features(n, features);
+#ifdef VIRTIO_HAS_EXTENDED_FEATURES