Messages in this thread | | | From | Yongji Xie <> | Date | Tue, 29 Jun 2021 10:26:40 +0800 | Subject | Re: Re: [PATCH v8 09/10] vduse: Introduce VDUSE - vDPA Device in Userspace |
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On Mon, Jun 28, 2021 at 12:40 PM Jason Wang <jasowang@redhat.com> wrote: > > > 在 2021/6/25 下午12:19, Yongji Xie 写道: > >> 2b) for set_status(): simply relay the message to userspace, reply is no > >> needed. Userspace will use a command to update the status when the > >> datapath is stop. The the status could be fetched via get_stats(). > >> > >> 2b looks more spec complaint. > >> > > Looks good to me. And I think we can use the reply of the message to > > update the status instead of introducing a new command. > > > > Just notice this part in virtio_finalize_features(): > > virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK); > status = dev->config->get_status(dev); > if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) { > > So we no reply doesn't work for FEATURES_OK. > > So my understanding is: > > 1) We must not use noreply for set_status() > 2) We can use noreply for get_status(), but it requires a new ioctl to > update the status. > > So it looks to me we need synchronize for both get_status() and > set_status(). >
We should not send messages to userspace in the FEATURES_OK case. So the synchronization is not necessary.
Thanks, Yongji
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