Re: [PATCH 0/3][RFC] PV Passthrough PCI Device Hotplug Support

[Yosuke Iwamatsu <y-iwamatsu@ab.jp.nec.com>]

Keir Fraser wrote:
> I mean have an extra global node called e.g., reconfigure. Set to 1 when
> pciback has updated hotplug info, causes pcifront to set reconfigure back to
> 0 and then re-scan the xenstore directory. Would that work?

Understood. Perhaps I'll give it a try in that manner.

> 
>> dev-# names are the physical names.
>> vdev-# becomes the same as dev-# when compiled with PCIDEV_BACKEND_PASS,
>> but different when compiled with other options (VPCI, SLOT).
>> vdev-# names are necessary for pcifront to recognize which devices are
>> to be detached.
> 
> Why would pcifront need to know the physical name? I would think that dev-#
> should be the virtual name.

dev-#, vdev-# and state-# are all backend nodes.
Xend writes physical names on dev-# to let pciback know which device
should be exported (This is the original behaviour).
Then pciback publishes the corresponding virtul name on vdev-#.
At the time of detachment, pcifront scans backend nodes and finds
which device should be removed by seeing vdev-#.
pcifront doesn't need to know the physical name indeed.

----
Yosuke

> 
>  -- Keir
>