From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Ilya Maximets <i.maximets@samsung.com>,
dev@dpdk.org, "Michael S . Tsirkin" <mst@redhat.com>,
Xiao Wang <xiao.w.wang@intel.com>
Cc: Tiwei Bie <tiwei.bie@intel.com>,
Zhihong Wang <zhihong.wang@intel.com>,
jfreimann@redhat.com, Jason Wang <jasowang@redhat.com>,
xiaolong.ye@intel.com, alejandro.lucero@netronome.com,
stable@dpdk.org
Subject: Re: [dpdk-stable] [PATCH v3 1/3] net/virtio: add missing barrier before reading the flags
Date: Thu, 10 Jan 2019 15:31:01 +0100 [thread overview]
Message-ID: <e9bd6e0d-a99d-ecba-9635-e85c6acec6e7@redhat.com> (raw)
In-Reply-To: <20190109145015.3010-2-i.maximets@samsung.com>
On 1/9/19 3:50 PM, Ilya Maximets wrote:
> Reading the used->flags could be reordered with avail->idx update.
> vhost in kernel disables notifications for the time of packets
> receiving, like this:
>
> 1. disable notify
> 2. process packets
> 3. enable notify
> 4. has more packets ? goto 1
>
> In case of reordering, virtio driver could read the flags on
> step 2 while notifications disabled and update avail->idx after
> the step 4, i.e. vhost will exit the loop on step 4 with
> notifications enabled, but virtio will not notify.
>
> Fixes: c1f86306a026 ("virtio: add new driver")
> CC: stable@dpdk.org
>
> Reported-by: Shahaf Shuler <shahafs@mellanox.com>
> Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
> ---
> drivers/net/virtio/virtqueue.h | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Thanks,
Maxime
prev parent reply other threads:[~2019-01-10 14:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20181226163712.31596-1-i.maximets@samsung.com>
[not found] ` <20190109145015.3010-1-i.maximets@samsung.com>
[not found] ` <CGME20190109145027eucas1p2437215de0df4c691eb84d4e84bfc71e5@eucas1p2.samsung.com>
2019-01-09 14:50 ` Ilya Maximets
2019-01-10 14:31 ` Maxime Coquelin [this message]
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