[Xen-devel] Xen 4.4 development update: Is PVH a blocker?

[George Dunlap <George.Dunlap@xxxxxxxxxxxxx>]

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

Our timeline had us start the code freeze last Friday.  However, we
have not released an RC0 because we have been waiting for PVH dom0
support.  Adding bug fixes during RCs makes sense, but RC0 should
contain all of the functionality we expect to be in the final release.

PVH dom0 support is making progress, however it's not that clear when
it will actually be ready to be checked in.  The current discussion is
about refcounting the new p2m type, which is a tricky and delicate
operation (though luckily one which should be limited to domains which
use that type -- at the moment, exclusively PVH dom0s).

If we continue to wait, it is likely that the release will slip.  The question
then is, how long should we continue to wait before we cut our losses and
say we'll wait for PVH dom0 until 4.5?

It would be very nice to have an RC out before Christmas, so
enthusiasts can play around with it over the holidays.  One option
would be to set a date to cut the first RC -- say, next Friday 20
December -- and just use the most recent changeset to pass the
push-gate, whether it has dom0 PVH or not.

Or we can just wait, and take stock of the situation again in January.

Thoughts?

In other news, I will be on holiday and / or travelling for
conferences until 20 January; during that time, Ian Campbell has
agreed to take over my role as Release Coordinator.

= Timeline =

Here is our current timeline based on a 6-month release:

* Feature freeze: 18 October 2013
* Code freezing point: 18 November 2013
* First RCs: 6 December 2013  <== WE ARE HERE
* Release: 21 January 2014

Last updated: 13 December 2013

== 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
 - Spice usbredirection support for upstream qemu

* PHV domU (experimental only)

* pvgrub2 checked into grub upstream

* ARM64 guest

* Guest EFI booting (tianocore)

* kexec

* Testing: Xen on ARM

* Update to SeaBIOS 1.7.3.1

* Update to qemu 1.6

* SWIOTLB (in Linux 3.13)

* Disk: indirect descriptors (in 3.11)

* Reworked ocaml bindings

== Resolved since last update ==

* Supposed regression from a3513737 ("x86: allow guest to set/clear

* qemu-traditional mis-parses host bus 8 as 0
  - Invalid: parses "08" as octal, as qemu-xen does.
  - Just needs documenting (see below)

== Open ==

* xl support for vnc and vnclisten options with PV guests
 > http://bugs.xenproject.org/xen/bug/25
 Blocker?

* 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

* xl needs to disallow PoD with PCI passthrough
  >see 
http://xen.1045712.n5.nabble.com/PATCH-VT-d-Dis-allow-PCI-device-assignment-if-PoD-is-enabled-td2547788.html

* qemu-upstream not freeing pirq
 > http://www.gossamer-threads.com/lists/xen/devel/281498
 > http://marc.info/?l=xen-devel&m=137265766424502
 status: patches posted; latest patches need testing
 Not a blocker.

* 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
 Not a blocker.

* xl does not support specifying virtual function for passthrough device
 > http://bugs.xenproject.org/xen/bug/22
 Too much work to be a blocker.

* 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

* Win2k3 SP2 RTC infinite loops
   > Regression introduced late in Xen-4.3 development
   owner: andrew.cooper@citrix
   status: patches posted, undergoing review. ( v2 ID
1386241748-9617-1-git-send-email-andrew.cooper3@xxxxxxxxxx )

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

* PCI hole resize support hvmloader/qemu-traditional/qemu-upstream
with PCI/GPU passthrough
  > http://lists.xen.org/archives/html/xen-devel/2013-05/msg02813.html
  > Where Stefano writes:
  > 2) for Xen 4.4 rework the two patches above and improve
  > i440fx_update_pci_mem_hole: resizing the pci_hole subregion is not
  > enough, it also needs to be able to resize the system memory region
  > (xen.ram) to make room for the bigger pci_hole

* qemu memory leak?
  > http://lists.xen.org/archives/html/xen-users/2013-03/msg00276.html

* qemu-* parses "008" as octal in USB bus.addr format
  > http://bugs.xenproject.org/xen/bug/15
  > just needs documenting

=== Big ticket items ===

* PVH dom0 (w/ Linux)
  blocker
  owner: mukesh@oracle, george@citrix
  status (Linux): Acked, waiting for ABI to be nailed down
  status (Xen): v6 posted; considered a blocker

* 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

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