The vhost_scsi example application negotiates the
VIRTIO_RING_F_EVENT_IDX feature bit but does not honor it when accessing
vrings.
In particular, commit e37ff954405addb8ea422426a2d162d00dcad196 ("vhost:
support virtqueue interrupt/notification suppression") broke vring call
because vq->last_used_idx is never updated by vhost_scsi. The
vq->last_used_idx field is not even available via the librte_vhost
public API, so VIRTIO_RING_F_EVENT_IDX is currently only usable by the
built-in virtio_net.c driver in librte_vhost.
This patch drops VIRTIO_RING_F_EVENT_IDX from vhost_scsi so that vring
call works again.
Cc: Changpeng Liu <[email protected]>
Cc: Junjie Chen <[email protected]>
Signed-off-by: Stefan Hajnoczi <[email protected]>
---
examples/vhost_scsi/vhost_scsi.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/examples/vhost_scsi/vhost_scsi.c b/examples/vhost_scsi/vhost_scsi.c
index da01ad378..3cb4383e9 100644
--- a/examples/vhost_scsi/vhost_scsi.c
+++ b/examples/vhost_scsi/vhost_scsi.c
@@ -21,7 +21,6 @@
#include "scsi_spec.h"
#define VIRTIO_SCSI_FEATURES ((1 << VIRTIO_F_NOTIFY_ON_EMPTY) |\
- (1 << VIRTIO_RING_F_EVENT_IDX) |\
(1 << VIRTIO_SCSI_F_INOUT) |\
(1 << VIRTIO_SCSI_F_CHANGE))
--
2.14.3
