Difference between revisions of "Xen ARM TODO"

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|Desc=
 
|Desc=
 
Make VM save/restore and VM migration work on ARM.
 
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/2013-10/msg00192.html
+
|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
 
}}
 
}}
   
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Physical and virtual ITS support for GICv3.
 
Physical and virtual ITS support for GICv3.
 
|References=Work underway: http://marc.info/?i=1426775889-29442-1-git-send-email-vijay.kilari%40gmail.com
 
|References=Work underway: http://marc.info/?i=1426775889-29442-1-git-send-email-vijay.kilari%40gmail.com
}}
 
 
{{Open Project
 
|Project=Expose Wallclock time to guests
 
|Desc=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
 
 
}}
 
}}
   
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{{Open Project
 
{{Open Project
|Project=Support for DT /chosen/stdout-path node
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|Project=Investigation on HCR.FB
  +
|Desc=Setting HCR.FB will upgrade local flush instructions (TLB, instruction cache, branch predictor) to innershareable. It would be nice to benchmark the performance impact on a UP-aware kernel and see if this could be reduced by flushing when a vCPU is migrating to another physical CPUs.
|Desc=ePAPR 1.1 3.5 defines the /chosen/stdout-path property which contains the path to the serial device as a string.
 
  +
|References=http://lists.xen.org/archives/html/xen-devel/2016-04/msg03157.html
 
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.
 
** Probably not necessary for Linux after http://article.gmane.org/gmane.linux.ports.arm.kernel/393828 happens, although perhaps useful for other OSes
 
 
|References=https://www.power.org/documentation/epapr-version-1-1/ https://git.kernel.org/linus/a208ffd251d08ed7ba6bdf3ae1e423373fb12d3d https://git.kernel.org/linus/3482f2c52b77bf6596e24aae82e204a0603eba66
 
 
}}
 
}}
 
{{Open Project
 
|Project=VCPU virtual time support
 
|Desc=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
 
}}
 
 
 
   
 
[[Category:XenARM]]
 
[[Category:XenARM]]

Latest revision as of 10:22, 27 April 2016

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

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

Investigation on HCR.FB
Contact: xen-devel@lists.xen.org
Description: Setting HCR.FB will upgrade local flush instructions (TLB, instruction cache, branch predictor) to innershareable. It would be nice to benchmark the performance impact on a UP-aware kernel and see if this could be reduced by flushing when a vCPU is migrating to another physical CPUs.
References: http://lists.xen.org/archives/html/xen-devel/2016-04/msg03157.html