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: 18 November 2013 <<== WE ARE HERE
• First RC: 26 November 2013
• Release: 21 January 2014

Feedback on the estimated dates is welcome.

Last updated: 18 November

Completed

* Event channel scalability (FIFO event channels)

* Non-udev scripts for driver domains (non-Linux driver domains)

* Multi-vector PCI MSI (Hypervisor side)

* Improved Spice support on libxl
 - Added Spice vdagent support
 - Added Spice clipboard sharing support

* PHV domU (experimental only)

* Guest EFI booting (tianocore)

* kexec

* Testing: Xen on ARM

* Update to SeaBIOS 1.7.3.1

* pvgrub2 checked into grub upstream

Resolved since last update

* credit scheduler doesn't update other fields when tslice updated from sysctl

Open

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

* 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: Patches posted

* Supposed regression from a3513737 ("x86: allow guest to set/clear
 > MSI-X mask bit (try 2)"), as per
 > http://lists.xenproject.org/archives/html/xen-devel/2013-09/msg01589.html.

* qemu-traditional mis-parses host bus 8 as 0
 > http://bugs.xenproject.org/xen/bug/15

* xen_platform_pci=0 doesn't work with qemu-xen
 > http://bugs.xenproject.org/xen/bug/20

* xl does not support specifying virtual function for passthrough device
 > http://bugs.xenproject.org/xen/bug/22

* 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

* 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

* HPET interrupt stack overflow (when using hpet_broadcast mode and MSI
capable HPETs)
  owner: andyh@citrix
  status: patches posted, undergoing review iteration.

Backlog

Testing coverage

* new libxl w/ previous versions of xl
 @IanJ

* Host S3 suspend
 @bguthro, @dariof

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

* Storage driver domains
 @roger

* HVM pci passthrough
 @anthony

* PV pci passthrough
 @konrad (or @george if he gets to it first)

* Network driver domains
 @George

* 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

* performance benchmarks
  @dario

Meta-items (composed of other items)

* Meta: PVIO NUMA improvements
 - NUMA affinity for vcpus (4.4 possible)
 - PV guest NUMA interface (4.4 possible)
 - Sensible dom0 NUMA layout 
 - Toolstack pinning backend thread / virq to appropraite d0 vcpu
 - NUMA-aware ballooning

* xend still in tree (x)
 - xl list -l on a dom0-only system
 - xl list -l doesn't contain tty console port
 - xl Alternate transport support for migration*
 - xl PVSCSI support
 - xl PVUSB support

Big ticket items

* PVH mode (w/ Linux)
  owner: mukesh@oracle, george@citrix
  status (Linux): Acked, waiting for ABI to be nailed down
  status (Xen): Initial version checked in, still nailing down interface

* Update to qemu 1.6
  owner: Anthonyper
  status: In staging, still working out a bug in the VMX code

* Live Migration Support
  owner: Jaeyong Yoo <jaeyong.yoo@samsung.com>
  status: v5 posted, looking good for code freeze

* ARM64 guest
  owner: IanC
  status: v3 posted, v4 in progress. looking good.

* SWIOTLB (kernel side thing)
  owner: Stefano
  status: Pull request sent.

* soft affinity for vcpus (was NUMA affinity for vcpus)
    owner: Dario
    status: v2 posted

* PV guest NUMA interface
    owner: Elena 
    status: v3 posted

* libvirt/libxl integration (external)
 - owner: jfehlig@suse, dario@citrix
 - patches posted (should be released before 4.4)
  - migration
  - PCI pass-through
 - In progress
  - integration w/ libvirt's lock manager
  - improved concurrency
 
* xl USB pass-through for HVM guests using Qemu USB emulation
  prognosis: Good if extended
  owner: George
  status: v6 patch series posted

* libxl: Spice usbredirection support for upstream qemu
 owner: fabio@M2R
 status: I'll post new patch version shortly
 
* libxl: usb2 and usb3 controller support for upstream qemu
 owner: fabio@M2R
 status: patch v5 posted, tested and working, awaiting reviews

* libxl network buffering support for Remus
   @shriram
   status: patches posted
   prognosis: fair

* Disk: indirect descriptors
   owner: roger@citrix
   status: Linux side in 3.11, Xen-side patch posted

Missed the feature freeze

* Sensible dom0 NUMA layout

* Toolstack pinning backend thread / virq to appropraite d0 vcpu

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

* NUMA-aware ballooning
   owner: Li Yechen
   status: in progress

* xl migrate transport improvements
 owner: None
 > See discussion here: http://bugs.xenproject.org/xen/bug/19
 - Option to connect over a plain TCP socket rather than ssh
 - xl-migrate-recieve suitable for running in inetd
 - option for above to redirect log output somewhere useful
 - Documentation for setting up alternate transports

* HVM guest NUMA
  owner: Matt Wilson@amazon
  status: in progress (?)

* qemu-upstream stubdom, Linux
   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.

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

* Network performance improvements
  owner: wei@citrix

* Xen EFI feature: Xen can boot from grub.efi
 owner: Daniel Kiper
 status: in progress

* Default to credit2
 status: Probably not for 4.4
 - cpu pinning
 - NUMA affinity
 - cpu "reservation"

* xenperf
  prognosis: Deferred to 4.5
  Owner: Boris Ostrovsky
  status: v2 patches posted

* Nested virtualization on Intel

* Nested virtualization on AMD

* Multi-vector PCI MSI (upstream Linux)
  owner: boris@oracle

* 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.

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

* New kexec implementation
  owner: dvrabel@citrix
  status: v7 posted, only minor updates expected

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
 > https://xenorg.uservoice.com/forums/172169-xen-development/suggestions/3924048-implement-xen-hypervisor-dmesg-log-entry-timestamp
 > Request seems to be for a shorter stamp (seconds-only, rather than full date)

* 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

* 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

* mac address changes on reboot if not specified in config file
  > Needs a robust way to "add" to the config

* 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
   - make word size arbitrary

* 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.

Wishlist / someday

* 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

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