Chardev websocket might not support pasting more than a few chars

[Anisse Astier]

When sending more than 4-5 characters on the websocket serial console (with pasting for example), the guest might not receive all of them, or worse interpret the input as Magic SysRq keys.

This might be due to the io loop not checking the backend readiness before calling the read function.

Attached patched fixes the problem on my system. I'm not sure it's the proper approach, this is just to start discussion.

[Daniel Berrange (berrange)]

If the problem only happens with a websockets channel enabled, it possibly a bug in the QIOChannelWebsock impl rather than the chardev

[Anisse Astier (anisse)]

I wrote a websocket client to help reproduce the bug without a browser:
https://github.com/anisse/websocktty

You can install it to your $GOPATH/bin (defaults to ~/go/bin) with "go get github.com/anisse/websocktty"

I can reproduce the bug with it by simply pasting a long-enough (5 to 20 characters) string.

I could not reproduce the bug with qemu's "-serial tcp" and netcat, so this problem might indeed be limited to the websock channel implementation.

[Thomas Huth (th-huth)]

The QEMU project is currently considering to move its bug tracking to
another system. For this we need to know which bugs are still valid
and which could be closed already. Thus we are setting older bugs to
"Incomplete" now.

If you still think this bug report here is valid, then please switch
the state back to "New" within the next 60 days, otherwise this report
will be marked as "Expired". Or please mark it as "Fix Released" if
the problem has been solved with a newer version of QEMU already.

Thank you and sorry for the inconvenience.

[Anisse Astier (anisse)]

The bug is still present.

[Thomas Huth (th-huth)]

This is an automated cleanup. This bug report has been moved to QEMU's
new bug tracker on gitlab.com and thus gets marked as 'expired' now.
Please continue with the discussion here:

 https://gitlab.com/qemu-project/qemu/-/issues/133