Re: [PATCH v7 28/46] vhost: make features 64 bit
From: Sergei Shtylyov
Date: Sun Nov 30 2014 - 10:44:44 EST
Hello.
On 11/30/2014 6:11 PM, Michael S. Tsirkin wrote:
We need to use bit 32 for virtio 1.0
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Reviewed-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/vhost/vhost.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 3eda654..c624b09 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;
@@ -174,6 +174,6 @@ enum {
static inline int vhost_has_feature(struct vhost_virtqueue *vq, int bit)
{
- return vq->acked_features & (1 << bit);
+ return vq->acked_features & (1ULL << bit);
Erm, wouldn't the high word be just dropped when returning *int*? I think
you need !!(vq->acked_features & (1ULL << bit)).
[...]
WBR, Sergei
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