Archived/Xen Roadmap/4.3

Proposed timeline

We are planning on a 9-month release cycle. Xen 4.2 was released on 17 September 2012. Based on that, below are our estimated dates:

• Feature Freeze: 25 March, 2013
• Code Freezing point: 15 April, 2013
• First RC: 6 May 2013
• Release: 17 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; but the general rule will be as follows:

• Between feature freeze and code freeze, only features which have had a v1 posted before the feature freeze, or are on this list, will be considered for inclusion.

• Between the "code freezing point" and the first RC, any new code will need to be justified, and it will become progressively more difficult to get non-bugfix patches accepted. Critera will include the size of the patch, the importance of the codepath, whether it's new functionality being added or existing functionality being changed, and so on.

Last updated 22 April 2013

Feature list

Below is a list of features we're tracking for this release. If you have updates to a tracked feature you are working on, or are working on a feature and wish it to be tracked, please let me know.

NB: Several of the items on this list marked (external). These are not part of the Xen tree, but are directly related to our users' experience (e.g., work in Linux or qemu) or to integration with other important projects (e.g., libvirt indings). Since all of these are part of the Xen community work, and comes from the same pool of labor, it makes sense to track the progress here, even though they won't explicitly be released as part of 4.3.

Meanings of prognoses:

• Excellent: It would be very unlikely for this not to be finished in time.
• Good: Everything is on track, and is likely to make it.
• Fair: A pretty good chance of making it, but not as certain
• Poor: Likely not to make it unless intervention is made
• Not for 4.3: Self-explanatory

Completed

* Serial console improvements
  -EHCI debug port

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

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

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

* Allow XSM to override IS_PRIV checks in the hypervisor

* Scalability: 16TiB of RAM

* xl QXL Spice support

* Install into /usr/local by default
  owner: Ian Campbell

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

* NUMA scheduler affinity

* ARM v7 server port (basic)
* ARM v8 server port (basic)

* vTPM updates

Bugs

* xl, compat mode, and older kernels
  owner: Wei Liu
  Many older 32-bit PV kernels that can run on a 64-bit hypervisor with
  xend do not work when started with xl.  The following work-around seems to
  work:
    xl create -p lightning.cfg
    xenstore-write /local/domain/$(xl domid lightning)/device/vbd/51713/protocol x86_32-abi
    xl unpause lightning
  This node is normally written by the guest kernel, but for older kernels
  seems not to be.  xend must have a work-around; port this work-around to xl.

* AMD NPT performance regression after c/s 24770:7f79475d3de7
  owner: ?
  Reference: http://marc.info/?l=xen-devel&m=135075376805215

* qemu-upstream: cd-insert and cd-eject not working
  http://marc.info/?l=xen-devel&m=135850249808960

* Revert Jan's debugging patch (commit bd9be94)
  owner: Jan Beulich

* Race condition in claim hypercall
  owner: Ian Jackson, Konrad Wilk

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

* Windows 2003 fails to install in Xen-unstable tip
  > Narrowed down to c/s 2fe82ac11fd078485388fe7c5e8bc3b6ac9185b0
  owner: Jan Beulich

Not yet completed

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

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

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

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

External projects (Not affected by feature freeze)

* 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

For future releases

* 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: ?
  prognosis: Poor
  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.

* qemu-based stubdom (Linux or BSD libc)
   owner: anthony@citrix
   status: in progress
   prognosis: ?
   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.

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

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

* Event channel scalability
  owner: wei@citrix or david@citrix
  status: RFC v5 submitted
  prognosis: Deciding whether to shoot for 3-level (4.3) or FIFO (4.4) 
  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): RFC submitted
  prognosis: Tech preview only

* blktap3
  owner: thanos@citrix
  status: RFCs posted
  prognosis: Not for 4.3

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

* Multi-page net protocol (external)
  owner: ijc@citrix or annie.li@oracle
  status: Initial patches posted (by Wei Liu)
  prognosis: Poor
  expand the network ring protocol to allow multiple pages for
  increased throughput

* Wait queues for mm
  owner: ?
  status: Draft posted Feb 2012; more work to do.
  prognosis: Poor

* Xen EFI feature: pvops dom0 able to make use of EFI run-time services (external)
 owner: Daniel Kiper
 status: Just begun
 prognosis: Probably not for 4.3 (?)

* Persistent grants for net
  owner: annie.li@citrix
  status: Initial implementation not getting expected gains; more investigation requried
  prognosis: Probably not for 4.3

* Serial console improvements
  owner: ?
  status: Stalled (see below)
  prognosis: Probably not for 4.3.
  -xHCI debug port (Needs hardware)
  -Firewire (needs hardware)

* Make storage migration possible
  owner: ?
  status: none
  prognosis: Probably delay until 4.4
  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
  prognosis: Probably delay until 4.4
  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
  prognosis: Probably need 4.4
  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
  prognosis: Prob put off until 4.4 (or GSoC project)
  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
  prognosis: Prob put off until 4.4

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

* IllumOS (OpenSolaris fork) support
  owner: Igor Kozhukov
  status: Stopped