Re: [libvirt] [Qemu-devel] Transitioning from HMP to QMP for QEMU

On 2011-12-15 14:38, Lucas Meneghel Rodrigues wrote: > On 12/15/2011 11:33 AM, Kevin Wolf wrote: >> Am 15.12.2011 14:18, schrieb Jan Kiszka: >>> On 2011-12-15 14:02, Stefan Hajnoczi wrote: >>>> What is the status of QEMU's transition from HMP to the QMP interface? >>>> >>>> My current understanding is that QEMU provides new HMP commands for >>>> humans, but HMP is being phased out as an API. Management tools >>>> should rely only on QMP for new commands. That would mean new HMP >>>> commands are not guaranteed to produce backwards-compatible output >>>> because tools are not supposed to parse the output. >>>> >>>> On the libvirt side, new QEMU features should only be supported via >>>> the json monitor in the future (i.e. human monitor patches should not >>>> be sent/merged)? Existing HMP commands will still need the human >>>> monitor support in order to handle old QEMU versions gracefully, but >>>> I'm thinking about new commands only. >>>> >>>> Does everyone agree on this? I think this is an important discussion >>>> if we want our management interface to get better and more consistent >>>> in the future. >>> >>> To phase out the classic HMP implementation, we need an internal >>> HMP-over-JSON wrapper (with tab expansion etc.) so that virtual console >>> and gdbstub monitors continue to benefit from new commands. Those >>> interfaces will stay for a long time, I'm sure. >> >> I think we're not talking about dropping HMP here, only about how long >> to support it as a stable API for management tools. I believe that we >> have been in a transitional phase for long enough now that we can start >> changing the output format of HMP commands without considering it an API >> breakage. > > Yes, I've got the same impression. But while we are at it, forgive my > naiveness, but wouldn't be worthwhile to consider dropping the human > monitor in the long run? Surely not the interface (for virtual console & gdbstub), but the internal implementation I hope.