From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH] virtio: fix the vq size issue Date: Fri, 17 Jul 2015 12:42:02 +0200 Message-ID: <2270958.zeR53oyNJH@xps13> References: <1435736930-26737-1-git-send-email-changchun.ouyang@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: dev@dpdk.org To: stephen@networkplumber.org Return-path: Received: from mail-wi0-f173.google.com (mail-wi0-f173.google.com [209.85.212.173]) by dpdk.org (Postfix) with ESMTP id 706935A3E for ; Fri, 17 Jul 2015 12:43:15 +0200 (CEST) Received: by wibud3 with SMTP id ud3so36090459wib.1 for ; Fri, 17 Jul 2015 03:43:15 -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" Stephen, This patch is partially reverting yours: http://dpdk.org/browse/dpdk/commit/?id=d78deadae4dca240 A comment or a ack? 2015-07-07 02:32, Ouyang, Changchun: > > > -----Original Message----- > > From: Ouyang, Changchun > > Sent: Wednesday, July 1, 2015 3:49 PM > > To: dev@dpdk.org > > Cc: Cao, Waterman; Xu, Qian Q; Ouyang, Changchun > > Subject: [PATCH] virtio: fix the vq size issue > > > > This commit breaks virtio basic packets rx functionality: > > d78deadae4dca240e85054bf2d604a801676becc > > > > The QEMU use 256 as default vring size, also use this default value to > > calculate the virtio avail ring base address and used ring base address, and > > vhost in the backend use the ring base address to do packet IO. > > > > Virtio spec also says the queue size in PCI configuration is read-only, so virtio > > front end can't change it. just need use the read-only value to allocate space > > for vring and calculate the avail and used ring base address. Otherwise, the > > avail and used ring base address will be different between host and guest, > > accordingly, packet IO can't work normally. > > > > Signed-off-by: Changchun Ouyang > > --- > > drivers/net/virtio/virtio_ethdev.c | 14 +++----------- > > 1 file changed, 3 insertions(+), 11 deletions(-) > > > > diff --git a/drivers/net/virtio/virtio_ethdev.c > > b/drivers/net/virtio/virtio_ethdev.c > > index fe5f9a1..d84de13 100644 > > --- a/drivers/net/virtio/virtio_ethdev.c > > +++ b/drivers/net/virtio/virtio_ethdev.c > > @@ -263,8 +263,6 @@ int virtio_dev_queue_setup(struct rte_eth_dev *dev, > > */ > > vq_size = VIRTIO_READ_REG_2(hw, VIRTIO_PCI_QUEUE_NUM); > > PMD_INIT_LOG(DEBUG, "vq_size: %d nb_desc:%d", vq_size, > > nb_desc); > > - if (nb_desc == 0) > > - nb_desc = vq_size; > > if (vq_size == 0) { > > PMD_INIT_LOG(ERR, "%s: virtqueue does not exist", > > __func__); > > return -EINVAL; > > @@ -275,15 +273,9 @@ int virtio_dev_queue_setup(struct rte_eth_dev > > *dev, > > return -EINVAL; > > } > > > > - if (nb_desc < vq_size) { > > - if (!rte_is_power_of_2(nb_desc)) { > > - PMD_INIT_LOG(ERR, > > - "nb_desc(%u) size is not powerof 2", > > - nb_desc); > > - return -EINVAL; > > - } > > - vq_size = nb_desc; > > - } > > + if (nb_desc != vq_size) > > + PMD_INIT_LOG(ERR, "Warning: nb_desc(%d) is not equal to > > vq size (%d), fall to vq size", > > + nb_desc, vq_size); > > > > if (queue_type == VTNET_RQ) { > > snprintf(vq_name, sizeof(vq_name), "port%d_rvq%d", > > -- > > 1.8.4.2 > > Any more comments for this patch? > > Thanks > Changchun >