Re: [PATCH v2 0/6] virtio-console: notify about the terminal size

[Daniel P . Berrangé]

On Wed, Jun 24, 2020 at 01:26:34PM +0200, Szymon Lukasz wrote:
> In this series resize notifications are only supported for the stdio
> backend but I think it should be easy to add support for the vc backend.
> Support for tty/serial backends is complicated by the fact that there is
> no clean way to detect resizes of the underlying terminal.

In a libvirt managed scenario it is typical to have the virtio console
connected to a UNIX socket. It would be desirable to have a way to
deal with resizes there.

QEMU socket chardev (TCP & UNIX socket) supports a "telnet" protocol
addition. Currently it doesn't almost nothing useful, but in theory
we could wire up support for the telnet resize message:

   https://tools.ietf.org/html/rfc1073


Another option is to allow dealing with resizes out of band, via the
QMP monitor. ie we can introduce a qmp_chardev_winsize command that
a client app can use to trigger the resize message to the guest OS.
>From libvirt's POV, this would be quite easy to support & useful to
have.


Regards,
Daniel
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