On 2015/11/19 15:31, Yuanhan Liu wrote: > On Thu, Nov 19, 2015 at 02:58:56PM +0900, Tetsuya Mukawa wrote: >> On 2015/11/19 14:45, Yuanhan Liu wrote: >>> On Thu, Nov 19, 2015 at 02:14:13PM +0900, Tetsuya Mukawa wrote: >>>> On 2015/11/19 12:33, Yuanhan Liu wrote: >>>>> On Thu, Nov 19, 2015 at 12:13:38PM +0900, Tetsuya Mukawa wrote: >>>>>> On 2015/11/19 11:18, Yuanhan Liu wrote: >>>>>>> On Thu, Nov 19, 2015 at 11:03:50AM +0900, Tetsuya Mukawa wrote: >>>>>>>> On 2015/11/17 22:29, Yuanhan Liu wrote: >>>>>>>>> On Fri, Nov 13, 2015 at 02:20:30PM +0900, Tetsuya Mukawa wrote: >>>>>>>>>> These variables are needed to be able to manage one of virtio devices >>>>>>>>>> using both vhost library APIs and vhost PMD. >>>>>>>>>> For example, if vhost PMD uses current callback handler and private >>>>>>>>>> data >>>>>>>>>> provided by vhost library, A DPDK application that links vhost >>>>>>>>>> library >>>>>>>>>> cannot use some of vhost library APIs. >>>>>>>>> Can you be more specific about this? >>>>>>>>> >>>>>>>>> --yliu >>>>>>>> How about like below? >>>>>>>> >>>>>>>> commit log: >>>>>>>> Currently, when virtio device is created and destroyed, vhost library >>>>>>>> will call one of callback handlers. >>>>>>>> The vhost PMD need to use this pair of callback handlers to know which >>>>>>>> virtio devices are connected actually. >>>>>>>> Because we can register only one pair of callbacks to vhost library, if >>>>>>>> the PMD use it, DPDK applications >>>>>>>> cannot have a way to know the events. >>>>>>> Will (and why) the two co-exist at same time? >>>>>> Yes it is. Sure, I will describe below in commit log. >>>>>> >>>>>> Because we cannot map some of vhost library APIs to ethdev APIs, in some >>>>>> cases, we still >>>>>> need to use vhost library APIs for a port created by the vhost PMD. One >>>>>> of example is >>>>>> rte_vhost_enable_guest_notification(). >>>>> I don't get it why it has something to do with a standalone PMD callback. >>>>> And if you don't call rte_vhost_enable_guest_notification() inside vhost >>>>> PMD, where else can you call that? I mean, you can't start vhost-pmd >>>>> and vhost-swithc in the mean time, right? >>>> No it's not true, even after connecting to virtio-net device, you can >>>> change the flag. >>>> It's just a hint for virtio-net driver, and it will be used while queuing. >>>> (We may be able to change the flag, even while sending or receiving >>>> packets) >>>> >>>>> And, pmd callback and the old notify callback will not exist at same >>>>> time in one case, right? If so, why is that needed? >>>>> >>>>> BTW, if it's a MUST, would you provide a specific example? >>>> Actually, this patch is not a MUST. >>>> >>>> But still the users need callback handlers to know when virtio-net >>>> device is connected or disconnected. >>>> This is because the user can call rte_vhost_enable_guest_notification() >>>> only while connection is established. >>> What does "the user" mean? Is there a second user of vhost lib besides >>> vhost PMD, that he has to interact with those connected devices? If so, >>> how? >> Sorry, my English is wrong. >> Not a second user. >> >> For example, If DPDK application has a port created by vhost PMD, then >> needs to call rte_vhost_enable_guest_notification() to the port. > So, you are mixing the usage of vhost PMD and vhost lib in a DPDK > application? Say,
Yes, that is my intention. Using ethdev(PMD) APIs and some library specific APIs to a same port is used in bonding PMD also. Thanks, Tetsuya > DPDK application > start_vhost_pmd > rte_vhost_driver_pmd_callback_register > rte_vhost_driver_callback_register > > I know little about PMD, and not quite sure it's a good combo. > > Huawei, comments? > > --yliu > >> DPDK application needs to know when virtio-net device is connected or >> disconnected, because the function is only valid while connecting. >> But without callback handler, DPDK application cannot know it. >> >> This is what I wanted to explain. >> >> Thanks, >> Tetsuya >> >>> --yliu >>>> Probably we can use link status changed callback of the PMD for this >>>> purpose. >>>> (The vhost PMD will notice DPDK application using link status callback) >>>> >>>> But I am not sure whether we need to implement link status changed >>>> callback for this purpose. >>>> While processing this callback handler, the users will only calls vhost >>>> library APIs that ethdev API cannot map, or store some variables related >>>> with vhost library. >>>> If so, this callback handler itself is specific for using vhost library. >>>> And it may be ok that callback itself is implemented as one of vhost >>>> library APIs. >>>> >>>> Tetsuya >>>> >>>>> --yliu >>>>>> Thanks, >>>>>> Tetsuya >>>>>> >>>>>> >>>>>>> --yliu >>>>>>> >>>>>>>> This may break legacy DPDK >>>>>>>> applications that uses vhost library. >>>>>>>> To prevent it, this patch adds one more pair of callbacks to vhost >>>>>>>> library especially for the vhost PMD. >>>>>>>> With the patch, legacy applications can use the vhost PMD even if they >>>>>>>> need additional specific handling >>>>>>>> for virtio device creation and destruction. >>>>>>>> For example, legacy application can call >>>>>>>> rte_vhost_enable_guest_notification() in callbacks to change setting. >>>>>>>> >>>>>>>> Tetsuya
