From patchwork Wed Jan 9 14:50:13 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ilya Maximets X-Patchwork-Id: 49545 X-Patchwork-Delegate: maxime.coquelin@redhat.com Return-Path: X-Original-To: patchwork@dpdk.org Delivered-To: patchwork@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 08E9C1B54D; Wed, 9 Jan 2019 15:50:30 +0100 (CET) Received: from mailout1.w1.samsung.com (mailout1.w1.samsung.com [210.118.77.11]) by dpdk.org (Postfix) with ESMTP id 2DA241B483 for ; Wed, 9 Jan 2019 15:50:29 +0100 (CET) Received: from eucas1p1.samsung.com (unknown [182.198.249.206]) by mailout1.w1.samsung.com (KnoxPortal) with ESMTP id 20190109145029euoutp012c32c5518147c31a2ab9c8d22f112ec0~4NZ7-JpG32916829168euoutp01W for ; Wed, 9 Jan 2019 14:50:29 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20190109145029euoutp012c32c5518147c31a2ab9c8d22f112ec0~4NZ7-JpG32916829168euoutp01W DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1547045429; bh=ACb/KwxvwG1hvivxOMf1qwvTHPXL3TEWz7TpZID/2Z4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lGbqli21sZJO4CNfQ4Pv7B1XZRAHFBLmeLCwzxGfIoX/j9fnqW0ldMQXcQ789z1Bh 0Q+91jDXAv/rl5eF/LRIxyqcK1NvwNVZ9GFdryPxE7WVWUUJlHKC4kkbcCZ6e8rN+E XZyXzadj8O77KxuqcGjapyIr8e++RqdtjTXEpAgM= Received: from eusmges3new.samsung.com (unknown [203.254.199.245]) by eucas1p1.samsung.com (KnoxPortal) with ESMTP id 20190109145028eucas1p1b03163ffd673d9404d972caf19c92072~4NZ7ce9nU2850028500eucas1p1O; Wed, 9 Jan 2019 14:50:28 +0000 (GMT) Received: from eucas1p2.samsung.com ( [182.198.249.207]) by eusmges3new.samsung.com (EUCPMTA) with SMTP id 24.40.04806.43A063C5; Wed, 9 Jan 2019 14:50:28 +0000 (GMT) Received: from eusmtrp1.samsung.com (unknown [182.198.249.138]) by eucas1p2.samsung.com (KnoxPortal) with ESMTPA id 20190109145027eucas1p2437215de0df4c691eb84d4e84bfc71e5~4NZ6s0UGs1641816418eucas1p2_; Wed, 9 Jan 2019 14:50:27 +0000 (GMT) Received: from eusmgms1.samsung.com (unknown [182.198.249.179]) by eusmtrp1.samsung.com (KnoxPortal) with ESMTP id 20190109145027eusmtrp10fbf3b12488adaf89b2339c5bd3ce828~4NZ6d_ObL0362703627eusmtrp1d; Wed, 9 Jan 2019 14:50:27 +0000 (GMT) X-AuditID: cbfec7f5-367ff700000012c6-c5-5c360a34c9ca Received: from eusmtip2.samsung.com ( [203.254.199.222]) by eusmgms1.samsung.com (EUCPMTA) with SMTP id A0.80.04284.33A063C5; Wed, 9 Jan 2019 14:50:27 +0000 (GMT) Received: from imaximets.rnd.samsung.ru (unknown [106.109.129.180]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20190109145026eusmtip239b51d7326abed050299e54503b0af36~4NZ5nkydu2099420994eusmtip2T; Wed, 9 Jan 2019 14:50:26 +0000 (GMT) From: Ilya Maximets To: dev@dpdk.org, Maxime Coquelin , "Michael S . Tsirkin" , Xiao Wang Cc: Tiwei Bie , Zhihong Wang , jfreimann@redhat.com, Jason Wang , xiaolong.ye@intel.com, alejandro.lucero@netronome.com, Ilya Maximets , stable@dpdk.org Date: Wed, 9 Jan 2019 17:50:13 +0300 Message-Id: <20190109145015.3010-2-i.maximets@samsung.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190109145015.3010-1-i.maximets@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprKKsWRmVeSWpSXmKPExsWy7djP87omXGYxBufnclmc+7SMyeLdp+1M Flfaf7JbLLv0mcni3JqlLBbHOvewWPz/9YrV4l/HH3aLrQ3/mSz2Pz/MbvHnjanF5ouTmBx4 PH4tWMrqsXjPSyaP6d0PmT3e77vK5tG3ZRVjAGsUl01Kak5mWWqRvl0CV8a87W3sBct5KpZe b2JuYGzh6mLk5JAQMJE4uOUwexcjF4eQwApGiZ2bZjFCOF8YJdbt3sgG4XxmlJg2+T8TTMvj bUegEssZJdavOsoMkhAS+MEocXoPJ4jNJqAjcWr1EbBRIgLdjBKvnn4G62AGKZqwsZkVpEpY IEjiV+8csG4WAVWJrd8esIDYvAJWEk0Nk6HWyUus3nAArIZTwFpi2asZbBDx6ewSH28IQ9gu Ev1nm1ghbGGJV8e3sEPYMhKnJ/ewQNj1EvdbXoJdJCHQwSgx/dA/qAX2EltenwNq4AC6TlNi /S59iLCjROfGXcwgYQkBPokbbwVBwsxA5qRt06HCvBIdbUIQ1SoSvw8uZ4awpSRuvvsMdYGH xPF/i5kggXWAUWL2qsWMExjlZyEsW8DIuIpRPLW0ODc9tdg4L7Vcrzgxt7g0L10vOT93EyMw sZz+d/zrDsZ9f5IOMQpwMCrx8Cb8M40RYk0sK67MPcQowcGsJMKrfsckRog3JbGyKrUoP76o NCe1+BCjNAeLkjhvNcODaCGB9MSS1OzU1ILUIpgsEwenVANjb47ahYbZkvL7+85GMh9dXn/6 Vc/LdQHJdmLm+0sntjkyae/+wGBUXaNYVLHzVf/THr9PJ5neKUpPfh/GoiN8mU+uQfjNx+Xb OHiC7rlle/swxOa7/FK8q8hcVWek2Mte4R8jfDVbcWF0uAf/TOG+K9JBjNPmPmjj+XrgbMXy lMAFszfURCuxFGckGmoxFxUnAgBrriA5KAMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrBLMWRmVeSWpSXmKPExsVy+t/xe7rGXGYxBj+/iVic+7SMyeLdp+1M Flfaf7JbLLv0mcni3JqlLBbHOvewWPz/9YrV4l/HH3aLrQ3/mSz2Pz/MbvHnjanF5ouTmBx4 PH4tWMrqsXjPSyaP6d0PmT3e77vK5tG3ZRVjAGuUnk1RfmlJqkJGfnGJrVK0oYWRnqGlhZ6R iaWeobF5rJWRqZK+nU1Kak5mWWqRvl2CXsa87W3sBct5KpZeb2JuYGzh6mLk5JAQMJF4vO0I WxcjF4eQwFJGiUvnmlghElISP35dgLKFJf5c64Iq+sYosfbdYUaQBJuAjsSp1UcYQRIiAv2M Eruv32QGcZgFGpgkZszczQJSJSwQIDF5xmF2EJtFQFVi67cHYHFeASuJpobJTBAr5CVWbzjA DGJzClhLLHs1gw3EFhLIkTj0ZSv7BEa+BYwMqxhFUkuLc9Nziw31ihNzi0vz0vWS83M3MQJD fduxn5t3MF7aGHyIUYCDUYmHN+GfaYwQa2JZcWXuIUYJDmYlEV71OyYxQrwpiZVVqUX58UWl OanFhxhNgY6ayCwlmpwPjMO8knhDU0NzC0tDc2NzYzMLJXHe8waVUUIC6YklqdmpqQWpRTB9 TBycUg2MGm1v7FUuNzSncuosC2grbufK3Z+74m3APaMDl5b6PJlSISgSPvng6r2KL6T8Gjfy 8PoV/6r6LPZL5mVOpfqLOUbO0k7O8t/qmh7sOZV99+AJL8OdnRc3qhVLzitjEq/KXDSv+0qX PP/kvSzzfmf41CSuKIiQzd9rfo3NKSz3SeuMhtqtp1iVWIozEg21mIuKEwH7+xM5iwIAAA== X-CMS-MailID: 20190109145027eucas1p2437215de0df4c691eb84d4e84bfc71e5 X-Msg-Generator: CA X-RootMTR: 20190109145027eucas1p2437215de0df4c691eb84d4e84bfc71e5 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20190109145027eucas1p2437215de0df4c691eb84d4e84bfc71e5 References: <20181226163712.31596-1-i.maximets@samsung.com> <20190109145015.3010-1-i.maximets@samsung.com> Subject: [dpdk-dev] [PATCH v3 1/3] net/virtio: add missing barrier before reading the flags X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 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 Signed-off-by: Ilya Maximets Reviewed-by: Maxime Coquelin --- drivers/net/virtio/virtqueue.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h index d8ae5cdec..dffa03669 100644 --- a/drivers/net/virtio/virtqueue.h +++ b/drivers/net/virtio/virtqueue.h @@ -415,6 +415,11 @@ vq_update_avail_ring(struct virtqueue *vq, uint16_t desc_idx) static inline int virtqueue_kick_prepare(struct virtqueue *vq) { + /* + * Ensure updated avail->idx is visible to vhost before reading + * the used->flags. + */ + virtio_mb(); return !(vq->vq_ring.used->flags & VRING_USED_F_NO_NOTIFY); } @@ -423,6 +428,9 @@ virtqueue_kick_prepare_packed(struct virtqueue *vq) { uint16_t flags; + /* + * Ensure updated data is visible to vhost before reading the flags. + */ virtio_mb(); flags = vq->ring_packed.device_event->desc_event_flags;