[Qemu-devel] KVM call minutes for June 8

[Chris Wright <chrisw@redhat.com>]

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

migration subsections.
- stable IDE version 3 is different for <= 0.12.2  than > 0.12.2
- for stable could bump to version 4, blacklist version 3
- unstable IDE version 4, works

APIC wiring problems (attached slides)
- postponed until tomorrow's code overview slot