Re: [dpdk-dev] [PATCH] virtio: fix used ring address calculation

["Tan, Jianfeng" <jianfeng.tan@intel.com>]

-----Original Message-----
From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Huawei Xie
Sent: Monday, September 21, 2015 11:39 AM
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH] virtio: fix used ring address calculation

used event idx is put at the end of available ring. It isn't taken into account when we calculate the address of used ring. Fortunately, it doesn't introduce the bug with fixed queue number 256 and 4KB alignment.

Signed-off-by: hxie5 <huawei.xie@intel.com>
---
 drivers/net/virtio/virtio_ring.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
index a16c499..92e430d 100644
--- a/drivers/net/virtio/virtio_ring.h
+++ b/drivers/net/virtio/virtio_ring.h
@@ -145,7 +145,7 @@ vring_init(struct vring *vr, unsigned int num, uint8_t *p,
 	vr->avail = (struct vring_avail *) (p +
 		num * sizeof(struct vring_desc));
 	vr->used = (void *)
-		RTE_ALIGN_CEIL((uintptr_t)(&vr->avail->ring[num]), align);
+		RTE_ALIGN_CEIL((uintptr_t)(&vr->avail->ring[num + 1]), align);
 }
 
 /*
--

Acked-by: Jianfeng Tan <Jianfeng.tan@intel.com>

1.9.3