* Yongji Xie <xieyongji@xxxxxxxxxxxxx> [2024-07-26 10:37:40]: > On Wed, Jul 24, 2024 at 11:38???AM Srivatsa Vaddagiri > <quic_svaddagi@xxxxxxxxxxx> wrote: > > > > Currently vduse does not seem to support configuration space writes > > (vduse_vdpa_set_config does nothing). Is there any plan to lift that > > limitation? I am aware of the discussions that took place here: > > > > The problem is that current virtio code can't allow the failure of config write. Ok got it. > > We will however likely need vduse to support configuration writes (guest VM > > updating configuration space, for ex: writing to 'events_clear' field in case of > > virtio-gpu). Would vduse maintainers be willing to accept config_write support > > for select devices/features (as long as the writes don't violate any safety > > concerns we may have)? > > > > It would be easier to support it if the config write just triggers an > async operation on the device side, e.g. a doorbell. That means we > can't ensure that any required internal actions on the device side > triggered by the config write have been completed after the driver > gets a successful return. But I'm not sure if this is your case. Yes posted write should be fine, as long as guest issues a read as a fence after that, which needs to be a sync point. As discussed in my earlier reply, we can explore injecting surprise removal event into guest where the VDUSE daemon does not respond within a timeout. Thanks vatsa
