Re: KVM call minutes for June 8

[Anthony Liguori <anthony@codemonkey.ws>]

On 06/08/2010 10:05 AM, Chris Wright wrote:
> Accelerating counters (aka moving PIT to userspace, keeping HPET in
> userspace)
> - PIT (in-kernel, userspace, or split)
> - userspace PIT, too slow
> - kernel PIT (already seen bugs)
> - split PIT, not realistic w/out a sane interface (see bugs above)
> - exit to userspace is a base cost, add MSR save/restore, add qemu
>    overhead...and exit to userspace is expensive
> - hpet in userspace (at least minimal counter reading)
> - ioapic
>    - less than half is architectural, more than half endds of being
>       interrupt reinjection
>
> Live migration + hotplug
> - start a machine, hotplug device, allocate ram...can't migrate
>    - last_offset and ramblock sections coming from cmdline may not be
>      compatible w/ hotplug
>    - worst case is different ramblock order and data corruption
> - alex has patches to convert ramblocks into queuelist
>    - give name, offset
>    - will clean up and send out today
>
> migration events?
> - QMP (wire protocol) has nice async events
>    - QError reasonable
>    - migration is async command, can complete w/ error or success
> - QMP broken for error
>    - need context for error, default is monitor, but async command
>    - redo qerror_report, propagate error (or always have error context
>      available)
> - monitor and qmp done w/ same dispatch functions
>    - should do monitor in terms of qmp
>      - every qerror replacing monitor printf error
>        - ends up not sharing enough ($foo not found, where $foo is contextual)
> - async command (pass in command completion)
> - may have to do limited (throw away for 0.13 and redo properly for 0.14)
> - anthony has a (not fully working) tree, and will document direction on wiki
>    

http://wiki.qemu.org/Features/QMP2

Includes a pointer to the current tree I'm working out of.

Regards,

Anthony Liguori