From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH] virtio: fix used ring address calculation Date: Thu, 24 Sep 2015 09:36:17 -0700 Message-ID: <20150924093617.6fd22053@urahara> References: <1442806742-32547-1-git-send-email-huawei.xie@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: "dev@dpdk.org" To: "Xie, Huawei" Return-path: Received: from mail-pa0-f53.google.com (mail-pa0-f53.google.com [209.85.220.53]) by dpdk.org (Postfix) with ESMTP id 3C2578E5D for ; Thu, 24 Sep 2015 18:36:07 +0200 (CEST) Received: by padhy16 with SMTP id hy16so77656448pad.1 for ; Thu, 24 Sep 2015 09:36:06 -0700 (PDT) In-Reply-To: List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Thu, 24 Sep 2015 07:30:41 +0000 "Xie, Huawei" wrote: > On 9/21/2015 11:39 AM, Xie, Huawei wrote: > vring_size calculation should consider both used_event_idx at the tail > of avail ring and avail_event_idx at the tail of used ring. > Will merge those two fixes and send a new patch. > > 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 > > --- > > 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); > > } > > > > /* > Why aren't we just using the standard Linux includes for this? See and the function vring_init() Keeping parallel copies of headers is prone to failures.