Xen 4.4 development update

[George Dunlap <George.Dunlap@eu.citrix.com>]

This information will be mirrored on the Xen 4.4 Roadmap wiki page:
 http://wiki.xen.org/wiki/Xen_Roadmap/4.4

Rather than try to predict precisely what will make it into what
release (which was something of a disaster last release), I'm just
going to borrow a term from the Agile world and call all uncompleted
features the "Backlog".  I'll still track who is doing what, and when
we get close, what state things seem to be in.

As mentioned in another e-mail, we'll also be working on improving the
regression tester.  Feel free to join us.

And as always, if you are working on a feature / bug that you want
tracked, please respond to this e-mail.

= Timeline =

As discussed elsewhere, I am proposing a 6-month release cycle.  Xen
4.3 was released on 9 July.  That would give us a release on 9 January
2014.  This is fairly close after the Christmas season, so I propose
to make the estimated release date later, on 21 January, giving a few
extra weeks for the holiday season:

* Feature freeze: 18 October 2013
* Code freezing point: 8 November 2013
* First RC: 26 November 2013
* Release: 21 January 2014

Feedback on the estimated dates  is welcome.

Last updated: 8 August 2013

== Completed ==

[none]

== Open ==

* xend still in tree

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

* __update_vcpu_system_time if system_time comes out negative

* xl pci-detach broken for pv guests?
  > http://bugs.xenproject.org/xen/bug/12
  > kernel doesn't know about moving into states 7 and 8
  status: External

* 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

== Backlog ==

=== Testing coverage ===

* Network driver domains
 @George

* new libxl w/ previous versions of xl
 @IanJ

* Host S3 suspend
 @bguthro

* Default [example] XSM policy
 @Stefano to ask Daniel D

* Xen on ARM
 # hardware
  @ianc
   emulator: @stefano to think about it

* Storage driver domains
 @roger

* HVM pci passthrough
 @anthony

* Nested virt?
 @intel (chased by George)

* Fix SRIOV test (chase intel)
 @ianj

* Fix bisector to e-mail blame-worthy parties
 @ianj

* Fix xl shutdown
  @ianj

* stub domains
  @athony

=== Big ticket items ===

* NUMA Memory migration
  owner: dario@citrix
  status: in progress

* Event channel scalability
  owner: david@citrix
  status: RFC v5 submitted
  Increase limit on event channels (currently 1024 for 32-bit guests,
  4096 for 64-bit guests)

* PVH mode (w/ Linux)
  owner: mukesh@oracle
  status (Linux): 3rd draft patches posted.
  status (Xen): v10 posted

* ARM stuff: ??

* Meta: PVIO NUMA improvements
 - NUMA affinity for vcpus
    owner: Dario
 - PV guest NUMA interface
    owner: Elena
 - Sensible dom0 NUMA layout
 - Toolstack pinning backend thread / virq to appropraite d0 vcpu

* qemu-upstream stubdom, Linux
   owner: anthony@citrix
   status: in progress
   qemu-upstream needs a more fully-featured libc than exists in
   mini-os.  Either work on a minimalist linux-based stubdom with
   glibc, or port one of the BSD libcs to minios.

* qemu-upstream stubdom, BSD libc
  owner: ianj@citrix

* Network performance improvements
  owner: wei@citrix

* Disk performance improvements

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

* libvirt/libxl integration (external)
 > need a status update
 - owner: jfehlig@suse, dario@citrix

* Default to credit2
 - cpu pinning
 - NUMA affinity
 - cpu "reservation"

* xenperf
  Owner: Boris Otovsky

* blktap3
  owner: thanos@citrix
  status: on hold pending XenServer decision

* Nested virtualization on Intel

* Nested virtualization on AMD

* Make storage migration possible
  owner: ?
  status: none
  There needs to be a way, either via command-line or via some hooks,
  that someone can build a "storage migration" feature on top of libxl
  or xl.

* Full-VM snapshotting
  owner: ?
  status: none
  Have a way of coordinating the taking and restoring of VM memory and
  disk snapshots.  This would involve some investigation into the best
  way to accomplish this.

* VM Cloning
  owner: ?
  status: none
  Again, a way of coordinating the memory and disk aspects.  Research
  into the best way to do this would probably go along with the
  snapshotting feature.

* xl vm-{export,import}
  owner: ?
  status: none
  Allow xl to import and export VMs to other formats; particularly
  ovf, perhaps the XenServer format, or more.

* Memory: Replace PoD with paging mechanism
  owner: george@citrix
  status: none

* PV audio (audio for stubdom qemu)
  owner: stefano.panella@citrix
  status: ?

* Wait queues for mm
 > Needed for more advanced paging schemes
  owner: ?
  status: Draft posted Feb 2012; more work to do.

* V4V: Inter-domain communication
  owner (Xen): dominic.curran@citrix.com
  status (Xen): patches submitted
  owner (Linux driver):  stefano.panella@citrix
  status (Linux driver): in progress

=== clean-ups ===

* Sort out better memory / ballooning / dom0 autoballooning thing
 > Don't forget NUMA angle
 - Inaccurate / incomplete info from HV

* Implement Xen hypervisor dmesg log entry timestamps

* Make network driver domains easier to set up / more useful
 - Default backend (submitted)
 - Remove unnecessary restriction wrt dom0 hotplug scripts (submitted)
 - Make it easy to make a device assignable (in discussion)
 - Automatically start/shutdown (xendomains?)
 - Pause booting of other domains until network driver domain is up

* libxl: More fine-grained control over when to pass through a device
 > Some IOMMUs are secure; some are merely functional, some are not present.
 > Allow the adminitrator to set the default

* xl does not handle migrate interruption gracefully
  > If you start a localhost migrate, and press "Ctrl-C" in the middle,
  > you get two hung domains
  status: Probably not for 4.3

* libxl / xl does not handle failure of remote qemu gracefully
  > Easiest way to reproduce:
  >  - set "vncunused=0" and do a local migrate
  >  - The "remote" qemu will fail because the vnc port is in use
  > The failure isn't the problem, but everything being stuck afterwards is
  status: Probably not for 4.3

* mac address changes on reboot if not specified in config file
  > Needs a robust way to "add" to the config
  status: Too much for 4.3

* qxl
  > http://bugs.xenproject.org/xen/bug/11http://bugs.xenproject.org/xen/bug/11
  - Uninitialized struct element in qemu
  - Revert 5479961 to re-enable qxl in xl,libxl
  - Option in Xen top-level to enable qxl support in qemu tree
  - Fix sse2 MMIO issue

* libxl config file

* libxl: Don't use RAW format for "URL"-based qdisks (e.g., rbd:rbd/foo.img)
  - Figure out whether to use a generic URL or have a specific type for each one
  - Check existence of disk file for all RAW

* Polish up xenbugtool
  owner: wei.liu2@citrix.com

* acpi-related xenstore entries not propagated on migrate
 > http://www.gossamer-threads.com/lists/xen/devel/282466
 > Only used by hvmloader; only a clean-up, not a bug.
 status: Not for 4.3

* Remove hardcoded mobprobe's in xencommons
  owner: Wei Liu
  status: still in discussion

* xl USB pass-through for HVM guests using Qemu USB emulation
  owner: George
  status: v6 patch series posted

* Rationalized backend scripts
  owner: roger@citrix
  status: patches posted

* Scripts for driver domains (depends on backend scripts)
  owner: roger@citrix
  status:

* Multi-vector PCI MSI (support at least for Dom0)
  owner: jan@suse
  status: Patches posted for Intel; AMD not yet done

* xl: passing more defaults in configuration in xl.conf
  owner: ?
  There are a number of options for which it might be useful to pass a
  default in xl.conf.  For example, if we could have a default
  "backend" parameter for vifs, then it would be easy to switch back
  and forth between a backend in a driver domain and a backend in dom0.

* xl PVUSB pass-through for PV guests
* xl PVUSB pass-through for HVM guests
  owner: George
  status: ?
  xm/xend supports PVUSB pass-through to guests with PVUSB drivers
(both PV and HVM guests).
  - port the xm/xend functionality to xl.
  - this PVUSB feature does not require support or emulation from Qemu.
  - upstream the Linux frontend/backend drivers. Current
work-in-progress versions are in Konrad's git tree.
  - James Harper's GPLPV drivers for Windows include PVUSB frontend drivers.

* Guest EFI booting
 - status: tianocore in-tree, some build problems.
   Needs new owner.

* Xen EFI feature: pvops dom0 able to make use of EFI run-time
services (external)
 owner: Daniel Kiper
 status: Just begun

* Serial console improvements
  owner: ?
  status: Stalled (see below)
  -xHCI debug port (Needs hardware)
  -Firewire (needs hardware)