[Qemu-devel] [repost] KVM call minutes for 2016-02-16

[Juan Quintela <quintela@redhat.com>]

Hi
[I mistyped qemu-devel@ address on first submission, sorry.]


Random ideas that I took for the talk, I hope that some of the active
participants can reply with a more coherent view.

State of the art (Andreas)
- Having very specific socket objects
- Dynamic allocation using new parameters
- Which level should we be doing the hotplug (granularity)
  x86-> socket level
  powerpc -> core
  z390 -> thread level

Christian
- Low level device adding
- Initialize from the beginning all cpu objects
  Hot-plugging would be to put them on-line
- how cpu came into being
- how are we going to add in x86 with device add
  * x86 and sparc -cpu handling is special case
  * not copy that on s390, better example in ARM?
- Way to handle this?
  * save the feature string internally, for reusing with new cpu
  * how best handle, it can depend of cpu model and board
  * how to make libvirt level not crazy?
  * should we hide the cpu add inside the machine implementation
  * having an array of empty sockets where to plug new cpus
  * only compatible types can be set on link property (not sure how well are enforced)
  * set the link property of the machine to the core object just created
  * powerpc cpu object is realized hook should check that it is done
    is a hot plug operation to automate this
  * powerpc only has cores and threads
  * we can have a property in the core object to know where it goes
  * if each core has two threads, when we add a new core, we always add 2 threads
  * cpu_add have a type={core,thread,whatever} what is the problem with it?
  * pre-created id's for cpu_add?
  * do different implementations and then try to find commonalities.
  * ARM can need to be able to add different cpu models
  * how to specify the topology
  * cpu_add has always thought to be an interim solution until we get the real one
  * problems with migration, specially with cpu_del
  * get cpu_add on x86
    * they don't support unplug
    * they don't support topology
  * realization matters about where we put the things, in child or parent object
  

Later, JUan.