On 10/09/2016 10:23, Maxime Coquelin wrote: > Currently, devices are plugged before features are negotiated. > If the backend doesn't support VIRTIO_F_VERSION_1, the transport > need to rewind some settings. > > This is the case for CCW, for which a post_plugged callback had > been introduced, where max_rev field is just updated if > VIRTIO_F_VERSION_1 is not supported by the backend. > For PCI, implementing the post_plugged would be much more > complicated, so it needs to know whether the backend supports > VIRTIO_F_VERSION_1 at plug time. > > Currently, nothing is done for PCI. Modern capabilitities get > exposed to the guest even if VIRTIO_F_VERSION_1 is not supported > by the backend, which confuses the guest. > > This patch proposes to replace existing post_plugged solution > with an approach that fits with both transports. > Features negociation is performed before ->device_plugged() call. > A pre_plugged callback is introduced so that the transports can > set their supported features.
Have you tested virtio-mmio too? Paolo
