From Xen
Revision as of 17:46, 2 July 2015 by Julieng (talk | contribs) (Point to the latest save/restore series)

This is a list of open work items and known bugs for the Xen on ARM with virtualization extension project.

In progress

Open Work Items

Save/restore and migration
Contact: xen-devel@lists.xen.org
Description: Make VM save/restore and VM migration work on ARM.
References: An initial prototype was written a couple of years ago for arm32 but never completed: http://lists.xen.org/archives/html/xen-devel/2014-06/msg02076.html

PCI device assignment to DomUs
Contact: xen-devel@lists.xen.org
Description: Assign one or more devices to an unprivileged guest, re-program the SMMU accordingly.
References: Not specified, useful references.

ITS support
Contact: xen-devel@lists.xen.org
Description: Physical and virtual ITS support for GICv3.
References: Work underway: http://marc.info/?i=1426775889-29442-1-git-send-email-vijay.kilari%40gmail.com

Expose Wallclock time to guests
Contact: xen-devel@lists.xen.org
Description: Current Xen on ARM does not popular the wallclock time fields of the shared info with anything useful. It should do so...
References: Partial/incomplete code http://article.gmane.org/gmane.comp.emulators.xen.devel/220265

More flexible early printk support
Contact: xen-devel@lists.xen.org
Description: Allow a single Xen binary to support multiple platforms for early_printk Rather than parsing the DTB early in asm to get the command line it would probably be sufficient to have a magic hex byte at a specific offset which could be edited by a simple tool.
References: http://lists.xen.org/archives/html/xen-devel/2014-02/msg01880.html

Support for DT /chosen/stdout-path node
Contact: xen-devel@lists.xen.org
Description: ePAPR 1.1 3.5 defines the /chosen/stdout-path property which contains the path to the serial device as a string.

We could potentially make two uses of this:

  • DONE Xen itself could use this property if it is present to set the default dtuart= option, saving users the hassle.
  • We could pass a suitable /chosen/stdout-path to dom0 to cause it to use hvc0 by default. This needs thinking through since hvc0 doesn't itself have a dt node.
References: https://www.power.org/documentation/epapr-version-1-1/ https://git.kernel.org/linus/a208ffd251d08ed7ba6bdf3ae1e423373fb12d3d https://git.kernel.org/linus/3482f2c52b77bf6596e24aae82e204a0603eba66

VCPU virtual time support
Contact: xen-devel@lists.xen.org
Description: Currently the concept of virtual time exposed to the guests is very simplistic and is just a static offset from physical time based on the time when the guest was started. We need to consider if this is actually what is needed/wanted and consider cases such as stolen time etc.
References: A patch series was sent to the LKML but never fully upstreamed: http://marc.info/?l=linux-arm-kernel&m=138929238127454&w=2