On Mon, Jun 04, 2018 at 12:12:21PM +0200, Gerd Hoffmann wrote: > On Mon, Jun 04, 2018 at 10:29:40AM +0100, Peter Maydell wrote: > > On 4 June 2018 at 10:20, Stefan Hajnoczi <stefa...@gmail.com> wrote: > > > Many of these inputs/outputs can be tied to an external UI. A degree of > > > timing precision is required so that the UI is responsive, although > > > cycle-accurate timing is not what I'd expect from QMP. > > > > Would we also be able to tie them to an internal UI, ie > > something that appears as another view in the GTK/etc > > UI frontends we have? > > Should be doable too. Basically a display device, which isn't a *real* > display but the UI. Could show a rendering of the board, simliar to how > web emulation environments are doing it. LED status could be rendered > directly to the board. A virtual mouse could map mouse clicks to button > presses. > > Doing more complex input that way (say a slider for the temperature > sensor) isn't going to work very well though ... > > Sensor input in general is pretty much unsupported in qemu.
For the micro:bit we've been thinking of a WebSocket monitor interface. This way a web UI can work with both local and remote QEMU instances. For security reasons, the WebSocket cannot be the regular QMP monitor. A slimmed down monitor is required with a subset of QMP commands and events. For example, users must not be able to migrate to an exec: destination so we need to ban that command on the UI monitor :-). Pros: + Remote control is possible over sockets (Important for hosting QEMU on a server. Nowadays this is becoming a popular way to deliver emulation to users. They don't need to install software locally.) + UI is cleanly isolated from QEMU process Cons: - Binary or high-frequency I/O is a bad fit for a JSON WebSocket interface I prefer the WebSocket route over creating a fake display that will not be able to implement complex widgets well. Gerd: What is your preference? Do you want board-specific fake displays inside the QEMU process as the long-term direction for UIs? Stefan
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