[Xen-devel] Xen 4.3 development update

[George Dunlap <George.Dunlap@xxxxxxxxxxxxx>]

There are basically three issues we're waiting to sort out (see below
for more info):
 * XSA-55
 * cpu hotplug in qemu-upsream
 * The MMIO hole issue

Unfortuantely, there is considerable uncertainty about how long it
will take for each of those to complete.  We're hoping to be able to
release maybe on the 19th,

This information will be mirrored on the Xen 4.3 Roadmap wiki page:
 http://wiki.xen.org/wiki/Xen_Roadmap/4.3

The key goals we're focusing on now, in order, are as follows:
 1. Have a bug-free 4.3 release
 2. Have an awesome 4.3 release
 3. Have a 4.3 release that happens on schedule (ready by June 15th)

The most important thing in making a case is to answer the question,
"If there are bugs in this patch, will they be discovered before the
June 17th release?"  The second most important thing is to consider the
cost/benefit analysis of bugs that are found: what is the risk of
introducing a bug which will delay the release, vs the benefit it will
have in making the release better?

= Timeline =

We are planning on a 9-month release cycle.  Based on that, below are
our estimated dates:
* Feature freeze: 25 March 2013
* Code freezing point: 15 April 2013
* First RC: 6 May 2013 <== WE ARE HERE
* Release: 19 June 2013

The RCs and release will of course depend on stability and bugs, and
will therefore be fairly unpredictable.  Each new feature will be
considered on a case-by-case basis.

The June 17th release is both an estimate and a goal.  At this point,
Xen 4.3 can be released whenever it's actually ready.  In fact, the
sooner we release, the sooner we can open the tree up for new
development and get on to 4.4 -- so keep fixing those bugs!

Last updated: 10 June 2013

== Completed ==

* Default to QEMU upstream (partial)
 - pci pass-thru (external)
 - enable dirtybit tracking during migration (external)
 - xl cd-{insert,eject} (external)

* openvswitch toostack integration
  To label "tech-preview" unless we get good testing (>10 individuals)

* NUMA scheduler affinity

* Install into /usr/local by default

* Allow config file to specify multiple usb devices for HVM domains

* Persistent grants for blk (external)
 - Linux
 - qemu

* Allow XSM to override IS_PRIV checks in the hypervisor

* vTPM updates

* Scalability: 16TiB of RAM

* CPUID-based idle (don't rely on ACPI info f/ dom0)

* Serial console improvements
  -EHCI debug port

== Bugs resolved since last update ==

* Revert Jan's debugging patch (commit bd9be94)
  resolution: reverted

* Migration w/ qemu-upstream causes stuck clock
  resolutoin: Fixed

* xl does not handle migrate interruption gracefully
  resolution: Not for 4.3

* libxl / xl does not handle failure of remote qemu gracefully
  resolution: Not for 4.3

== Open bugs ==

* cpu hotplug broken in qemu-xen
  > Upstream qemu has qmp interface; either implement our own way or backport
  > Issue in SeaBIOS: can wake up "unplugged" cpus!
  owner: Anthony
  status: In progress
  priority: blocker

* XSA-55
  status: v6 posted
  priority: blocker (?)

* qemu-upstream MMIO hole issue
 > http://lists.xen.org/archives/html/xen-devel/2013-03/msg00559.html
 > "You can reproduce it when a VM has a big pci hole size (such as
   512MB), e.g. create a VM with a virtual device which has a 512MB
   pci BAR."
 priority: high
 status: Original fix broken; investigating proper fix
 priority: blocker (?)

* xl pci-detach broken for pv guests?
  > http://bugs.xenproject.org/xen/bug/12
  status: Still investigating
  priority: Would be blocker if accurate

* Update 4.3-rc to 4.3 in README; add tag bragging about 4.3
  owner: George
  status: v1 sent, v2 pending

* perl 5.18 fails to compile qemu-traditional docs?
 > http://www.gossamer-threads.com/lists/xen/devel/284141
 status: discussion in progress
 priority: minor

* Scan through qemu-upstream changesets looking for important fixes
  (particularly for stubdoms) for qemu-traditional
  - cpu hotplug
  owner: Anthony

* qemu-upstream not freeing pirq
 > http://www.gossamer-threads.com/lists/xen/devel/281498
 priority: high
 status: patches posted

* AMD: IOMMU accidental clearing
  owner: Jan Beulich, Suravee Suthikulpanit
  status:

* __update_vcpu_system_time if system_time comes out negative
  status: Not for 4.3

== Not yet complete ==

* ARM v7 server port (basic)
* ARM v8 server port (basic)
 - Goal: Good Arndale support for 4.3
 - Regressions here will not slip the release, so development is ongoing

== External projects (Not affected by feature freeze) ==

* Race in PV shutdown between tool detection and shutdown watch
 > http://www.gossamer-threads.com/lists/xen/devel/282467
 > Nothing to do with ACPI
 status: Probably a bug in Linux xen drivers

* Multi-page blk rings (external)
 - blkback in kernel roger@citrix
 - qemu blkback
  status: Overall blk architecture being discussed
  prognosis: Fair

* Xen EFI feature: Xen can boot from grub.efi
 owner: Daniel Kiper
 status: Just begun
 prognosis: Fair

* libvirt/libxl integration (external)
 - Update libvirt to 4.2
   status: Patch accepted
 - Migration
   owner: cyliu@suse (?)
   status: first draft implemented, not yet submitted
   prognosis: ?
 - Itemize other things that need work
   To begin with, we need someone to go and make some lists:
   - Features available in libvirt/KVM not available in libvirt/libxl
     See http://libvirt.org/hvsupport.html
   - Features available in xl/Xen but not available in libvirt/Xen

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