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

To: Yosuke Iwamatsu <y-iwamatsu@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 0/3][RFC] PV Passthrough PCI Device Hotplug Support
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Thu, 21 Feb 2008 12:50:08 +0000
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On 21/2/08 12:37, "Yosuke Iwamatsu" <y-iwamatsu@xxxxxxxxxxxxx> wrote:

> If you are unwilling to change the main state node,
> watching individual device nodes may be a possible solution.
> In that case, we prepare pci slots for hotplug and make pciback/pcifront
> watch all the states of these slots. But I wonder if it is acceptable
> that pv drivers watch lots of xenstore nodes.
> I'm not sure about the idea to have a separate configuration node
> per device. Does that mean having pv drivers for each pci device?

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?

> 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.

 -- Keir

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