# \[PATCH v8 29/50\] vhost: make features 64 bit

- From: Michael S. Tsirkin \<mst@redhat.com\>
- Date: 2014-12-01 16:05:50 
- List: netdev
- Page: https://ratatoskr.run/netdev/2014/12/4385987
- Thread: https://ratatoskr.run/kvm/2014/12/4385987/t.md

```text
We need to use bit 32 for virtio 1.0.
Make vhost_has_feature bool to avoid discarding high bits.

Cc: Sergei Shtylyov <redacted>
Cc: Ben Hutchings <redacted>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jason Wang <redacted>
---
 drivers/vhost/vhost.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 3eda654..55a95c9 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -106,7 +106,7 @@ struct vhost_virtqueue {
 	/* Protected by virtqueue mutex. */
 	struct vhost_memory *memory;
 	void *private_data;
-	unsigned acked_features;
+	u64 acked_features;
 	/* Log write descriptors */
 	void __user *log_base;
 	struct vhost_log *log;
@@ -172,8 +172,8 @@ enum {
 			 (1ULL << VHOST_F_LOG_ALL),
 };
 
-static inline int vhost_has_feature(struct vhost_virtqueue *vq, int bit)
+static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 {
-	return vq->acked_features & (1 << bit);
+	return vq->acked_features & (1ULL << bit);
 }
 #endif
-- 
MST
```