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Re: [Xen-devel] [PATCH 0/3][RFC] PV Passthrough PCI Device Hotplug Suppo

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 0/3][RFC] PV Passthrough PCI Device Hotplug Support
From: Yosuke Iwamatsu <y-iwamatsu@xxxxxxxxxxxxx>
Date: Thu, 21 Feb 2008 22:25:43 +0900
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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.


 -- Keir

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