On Tue, Feb 26, 2019 at 01:32:24PM +0100, Maxime Coquelin wrote: > On 2/26/19 9:42 AM, Ilya Maximets wrote: > > On 26.02.2019 11:13, Liu, Changpeng wrote: > > > > > > > > > > -----Original Message----- > > > > From: Ilya Maximets [mailto:i.maxim...@samsung.com] > > > > Sent: Tuesday, February 26, 2019 3:39 PM > > > > To: Liu, Changpeng <changpeng....@intel.com>; dev@dpdk.org > > > > Cc: Stojaczyk, Dariusz <dariusz.stojac...@intel.com>; > > > > maxime.coque...@redhat.com; Bie, Tiwei <tiwei....@intel.com>; Wang, > > > > Zhihong <zhihong.w...@intel.com>; Jason Wang <jasow...@redhat.com> > > > > Subject: Re: vhost: add virtio configuration space access socket > > > > messages > > > > > > > > On 26.02.2019 10:01, Liu, Changpeng wrote: > > > > > > > > > > > > > > > > -----Original Message----- > > > > > > From: Ilya Maximets [mailto:i.maxim...@samsung.com] > > > > > > Sent: Monday, February 25, 2019 9:20 PM > > > > > > To: Liu, Changpeng <changpeng....@intel.com>; dev@dpdk.org > > > > > > Cc: Stojaczyk, Dariusz <dariusz.stojac...@intel.com>; > > > > > > maxime.coque...@redhat.com; Bie, Tiwei <tiwei....@intel.com>; Wang, > > > > > > Zhihong <zhihong.w...@intel.com>; Jason Wang <jasow...@redhat.com> > > > > > > Subject: Re: vhost: add virtio configuration space access socket > > > > > > messages > > > > > > > > > > > > On 25.02.2019 10:51, Changpeng Liu wrote: > > > > > > > This patch adds new vhost user messages GET_CONFIG and SET_CONFIG > > > > > > > used to get/set virtio device's PCI configuration space. > > > > > > > > > > > > Beside the fact that some additional description and reasoning > > > > > > required, > > > > > > I do not see the usage of this feature. You're defining the flag > > > > > > VHOST_USER_PROTOCOL_F_CONFIG, but it's never used. So, none of dpdk > > > > vhost > > > > > > backends (vdpa, vhost-user) will use this feature. > > > > > > You, probably, missed adding it to VHOST_USER_PROTOCOL_FEATURES or > > > > > > VDPA_SUPPORTED_PROTOCOL_FEATURES. > > > > > > > > > > > > From the other side, current implementation forces application to > > > > > > properly > > > > > > implement the get/set_config callbacks. Otherwise, receiving of the > > > > > > messages > > > > > > will result in RTE_VHOST_MSG_RESULT_ERR and subsequent vhost > > > > > > disconnection. > > > > > > This looks strange, because supported protocol features normally > > > > > > enabled by > > > > > > default. Am I misunderstood something ? > > > > > QEMU will not send the messages if VHOST_USER_PROTOCOL_F_CONFIG > > > > wasn't enabled. > > > > > > > > So, you're going to enable it only by explicit call to > > > > 'rte_vhost_driver_set_features' ? > > > > > > > > In this case I'm assuming that you're implementing your own vhost > > > > backend. > > > > But why you're not using 'dev->extern_ops' and corresponding > > > > 'pre_msg_handle' > > > > or 'post_msg_handle' to handle your GET/SET_CONFIG messages like it does > > > > 'vhost_crypto' backend ? > > > The patch was developed one year ago, while DPDK didn't have external ops. > > > > So, maybe it's time to reconsider the implementation. > > +1 > > > > The get_config/set_config was defined for all the virtio devices, so I > > > think it makes > > > more sense adding here. > > > > VHOST_USER_*_CRYPTO_SESSION messages are defined for all the virtio devices > > too, however they makes sense for vhost_crypto backend only. These messages > > (GET/SET_CONFIG) makes sense only when callbacks (get/set_config) are > > implemented, so IMHO it's better to implement their handlers along with the > > callbacks, i.e. inside the implementation of your vhost backend. > > > > Maxime, Tiwei, what do you think ? > > I would prefer it to be implemented in SPDK directly as a pre_handler > callback, as I don't foresee a need for it for other backends, and it > would avoid breaking the API. > > It would imply fixing the beginning of vhost_user_msg_handler() to accept > requests > VHOST_USER_MAX and add necessary check before doing > the debug logs. > > With above change we would also be able to remove VHOST_CRYPTO requests > from vhost_user.c, and we could then work on moving vhost-net bits > out of this file too.
+1 > > Regards, > Maxime >