On Mon, 2025-09-15 at 19:08 -0400, Michael S. Tsirkin wrote: > On Tue, Sep 16, 2025 at 01:02:02AM +0200, Filip Hejsek wrote: > > While thinking about the patches, a few questions about the virtio spec > > have popped into my head. > > > > 1. Should the config space size also be updated (for port 0) when > > multiport is used? Based on my reading of the spec, I think yes. > > > > 2. Can VIRTIO_CONSOLE_RESIZE be sent if VIRTIO_CONSOLE_F_SIZE is not > > negotiated? The spec does not say, which I think means it can. > > But the guest can't do anything useful here.
It can if the reason VIRTIO_CONSOLE_F_SIZE was not negotiated is that the host only supports sending size for multiport devices (e.g. because port 0 does not have size). > > 3. The spec says that reading from config space fields that are > > conditional on features should be allowed even if the driver has not > > (yet) accepted the feature. Does it mean that we have to update the > > size even if the feature is not accepted (yet), or is it OK if the > > reads return 0? > > This is talking about the window before FEATURES_OK (and so DRIVER_OK) > is set. It is best to update the size. There's no interrupt to send > though. > > > > Thanks for any answers or opinions, > > Filip Hejsek
