As discussed offline, this will lead to many DRIVER OK among dev_stop()/dev_start(). I'll remove this patch.
Thanks, Jianfeng > -----Original Message----- > From: Yuanhan Liu [mailto:yuanhan....@linux.intel.com] > Sent: Monday, December 26, 2016 4:02 PM > To: Tan, Jianfeng > Cc: dev@dpdk.org; Yigit, Ferruh; Liang, Cunming > Subject: Re: [PATCH v2 2/7] net/virtio_user: postpone DRIVER OK notification > > On Mon, Dec 26, 2016 at 06:55:16AM +0000, Tan, Jianfeng wrote: > > > > > > > -----Original Message----- > > > From: Yuanhan Liu [mailto:yuanhan....@linux.intel.com] > > > Sent: Monday, December 26, 2016 2:27 PM > > > To: Tan, Jianfeng > > > Cc: dev@dpdk.org; Yigit, Ferruh; Liang, Cunming > > > Subject: Re: [PATCH v2 2/7] net/virtio_user: postpone DRIVER OK > notification > > > > > > On Fri, Dec 23, 2016 at 07:14:21AM +0000, Jianfeng Tan wrote: > > > > In driver probe phase, we obtain device information; and then virtio > > > > driver will initialize device and stores info, like negotiated > > > > features, in vhost_user layer; finally, vhost_user gets DRIVER_OK > > > > notification from virtio driver, and then sync with backend device. > > > > > > > > Previously, DRIVER_OK could be sent twice: 1. when ether layer > invokes > > > > eth_device_init to initialize device; 2. when user configures it with > > > > different configuration from that of previous. > > > > > > Yes, but that's wrong. Now only 1) will be taken. > > > > >From code in virtio_dev_configure() as below, if hw_ip_checksum or > enable_lro is configured, the device will be reset and re-initialized. > > if (rxmode->hw_ip_checksum) > > req_features |= (1ULL << VIRTIO_NET_F_GUEST_CSUM); > > if (rxmode->enable_lro) > > req_features |= > > (1ULL << VIRTIO_NET_F_GUEST_TSO4) | > > (1ULL << VIRTIO_NET_F_GUEST_TSO6); > > > > /* if request features changed, reinit the device */ > > if (req_features != hw->req_guest_features) { > > ret = virtio_init_device(dev, req_features); > > if (ret < 0) > > return ret; > > } > > Yes, I know. But virtio_init_device() will call vtpci_reinit_complete() > at the end, doesn't it? > > > > > Since we can only depend on DRIVER_OK notification to sync with > backend > > > > device, we postpone it to virtio_dev_start when everything is settled. > > > > > > I don't quite understand what you were going to fix here; you don't > > > state it in the commit log after all. Normally, when everything is > > > negotiated (when DRIVER_OK is set), we should not set it again, unless > > > a reset has been happened. > > > > I agree that DRIVER_OK should be set only if everything is settled. Under > the case of hw_ip_checksum or enable_lro, a reset will be sent and the > device will be re-initialized. > > > > So my point is that since the configuration might be changed in > dev_configure(), why not just send DRIVER_OK after everything is done. > > > > > > > > If you look at QEMU, qemu will simply ignore it once vhost has already > > > started. > > > > It does not apply here. The configuration is changed, and it cannot be > ignored. > > Why it doesn't apply here? What makes virtio_user special? If it works > to QEMU and it doesn't to virtio_user, it basically means the virtio_user > is broken ... > > --yliu
