Re: ARM/PCI passthrough: libxl_pci, sysfs and pciback questions

[Jan Beulich <jbeulich@xxxxxxxx>]

On 27.10.2020 16:52, Oleksandr Andrushchenko wrote:
> On 10/27/20 2:55 PM, Roger Pau Monné wrote:
>> On Tue, Oct 27, 2020 at 09:59:05AM +0000, Oleksandr Andrushchenko wrote:
>>>    5. An alternative route for 3-4 could be to store that data in XenStore, 
>>> e.g.
>>>       MMIOs, IRQ, bind sysfs path etc. This would require more code on Xen 
>>> side to
>>>       access XenStore and won’t work if MMIOs/IRQs are passed via device 
>>> tree/ACPI
>>>       tables by the bootloaders.
>> As above, I think I need more context to understand what and why you
>> need to save such information.
> 
> Well, with pciback absence we loose a "database" which holds all the knowledge
> 
> about which devices are assigned, bound etc.

What hasn't become clear to me (sorry if I've overlooked it) is
why some form of pciback is not an option on Arm. Where it would
need to run in your split hardware-domain / Dom0 setup (if I got
that right in the first place) would be a secondary question.

Jan