From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <haifeng.lin@huawei.com>
Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [119.145.14.66])
 by dpdk.org (Postfix) with ESMTP id 598C3379E
 for <dev@dpdk.org>; Mon, 23 Mar 2015 03:29:39 +0100 (CET)
Received: from 172.24.2.119 (EHLO SZXEML429-HUB.china.huawei.com)
 ([172.24.2.119])
 by szxrg03-dlp.huawei.com (MOS 4.4.3-GA FastPath queued)
 with ESMTP id BDM34299; Mon, 23 Mar 2015 10:29:35 +0800 (CST)
Received: from [127.0.0.1] (10.177.19.115) by SZXEML429-HUB.china.huawei.com
 (10.82.67.184) with Microsoft SMTP Server id 14.3.158.1; Mon, 23 Mar 2015
 10:29:32 +0800
Message-ID: <550F7A8D.8040202@huawei.com>
Date: Mon, 23 Mar 2015 10:29:33 +0800
From: Linhaifeng <haifeng.lin@huawei.com>
User-Agent: Mozilla/5.0 (Windows NT 6.1;
 rv:31.0) Gecko/20100101 Thunderbird/31.1.0
MIME-Version: 1.0
To: <dev@dpdk.org>
References: <1426925237-8312-1-git-send-email-haifeng.lin@huawei.com>
In-Reply-To: <1426925237-8312-1-git-send-email-haifeng.lin@huawei.com>
Content-Type: text/plain; charset="windows-1252"
Content-Transfer-Encoding: 7bit
X-Originating-IP: [10.177.19.115]
X-CFilter-Loop: Reflected
X-Mirapoint-Virus-RAPID-Raw: score=unknown(0),
 refid=str=0001.0A020205.550F7A8F.01A8, ss=1, re=0.001, recu=0.000, reip=0.000,
 cl=1, cld=1, fgs=0, ip=0.0.0.0,
 so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32
X-Mirapoint-Loop-Id: ec9c3ed1220b0e0fe86c9649e880ae88
Subject: Re: [dpdk-dev] [PATCH] cast used->idx to volatile
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Mon, 23 Mar 2015 02:29:40 -0000

cc changchun.ouyang@intel.com
cc huawei.xie@intel.com

On 2015/3/21 16:07, linhaifeng wrote:
> From: Linhaifeng <haifeng.lin@huawei.com>
> 
> Same as rte_vhost_enqueue_burst we should cast used->idx
> to volatile before notify guest.
> 
> Signed-off-by: Linhaifeng <haifeng.lin@huawei.com>
> ---
>  lib/librte_vhost/vhost_rxtx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
> index 535c7a1..8d674d1 100644
> --- a/lib/librte_vhost/vhost_rxtx.c
> +++ b/lib/librte_vhost/vhost_rxtx.c
> @@ -722,7 +722,7 @@ rte_vhost_dequeue_burst(struct virtio_net *dev, uint16_t queue_id,
>  	}
>  
>  	rte_compiler_barrier();
> -	vq->used->idx += entry_success;
> +	*(volatile uint16_t *)&vq->used->idx += entry_success;
>  	/* Kick guest if required. */
>  	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
>  		eventfd_write((int)vq->callfd, 1);
> 

-- 
Regards,
Haifeng