Re: [Xen-devel] Re: pvusb drivers for pvops 2.6.32.x kernel

[Nathanael Rensen <nathanael@xxxxxxxxxxxxxxxx>]

On Tue, Jan 04, 2011 at 09:33:39AM +0000, Ian Campbell wrote:
>
> I think the correct path for this functionality is to first get it
> accepted into the upstream kernel by working with the USB subsystem
> maintainer+list, fixing the issue arising from their review etc.

I'm happy to have a shot at that. I don't imagine it will be a quick
process so in the meantime I think there is value in supporting pvusb
in stable/2.6.32.x to encourage people to test and identify issues,
and also to make it easier to track the maintenance.

> The stuff necessary to get the frontend upstream has been upstream for
> ages. For the backend basic dom0 boot support is in 2.6.37 and the
> generic scaffolding for backends is currently in linux-next (via
> Konrad's tree) and is intended to be in the next merge window.
>
> I think the backend just looks like a regular USB driver to the host
> system so it probably belongs in drivers/usb/<something>/xen-usbback/
> and not drivers/xen. (I'm not sure what the <something> should be,
> perhaps "misc").

I agree that the frontend driver looks like a regular USB host
controller driver and belongs in drivers/usb/host. From the dom0
perspective the backend driver is a consumer of USB services rather
than a provider so my inclination is that the proper place for the
backend is drivers/xen along with blkback, netback and pciback. Much
the same way as I would expect to find a USB TV tuner driver in
drivers/media rather than drivers/usb. I would prefer to remain
consistent with the model established by the block, net and pci
drivers, but I am happy to adopt whatever convention is acceptable to
upstream.

Nathanael

> Ian.

>> > ----- Forwarded message from Nathanael Rensen <nathanael@xxxxxxxxxxxxxxxx> 
>> > -----
>> >
>> > From: Nathanael Rensen <nathanael@xxxxxxxxxxxxxxxx>
>> > To: Pasi Kärkkäinen <pasik@xxxxxx>
>> > Cc: n_iwamatsu@xxxxxxxxxxxxxx
>> > Date: Mon, 3 Jan 2011 19:32:23 +0800
>> > Subject: Re: pvusb for pvops
>> >
>> > On 1 January 2011 23:19, Nathanael Rensen <nathanael@xxxxxxxxxxxxxxxx> 
>> > wrote:
>> > > On 1 January 2011 22:43, Pasi Kärkkäinen <pasik@xxxxxx> wrote:
>> > >> On Sat, Jan 01, 2011 at 03:10:58AM +0800, Nathanael Rensen wrote:
>> > >>> Hi Noboru,
>> > >>>
>> > >>> In case it is helpful ...
>> > >>>
>> > >>> I've attached a diff that adds the pvusb drivers to the debian squeeze
>> > >>> 2.6.32 pvops kernel.
>> > >>> So far I've only tested with a USB drive on xen 4.0.1 between debian
>> > >>> squeeze pvops dom0 and
>> > >>> debian squeeze pvops domU.
>> > >>>
>> > >>> The diff is based on the SLES SP1 diffs posted here:
>> > >>>   http://code.google.com/p/gentoo-xen-kernel/downloads/list
>> > >>> It almost applies cleanly to xen/stable-2.6.32.x except for the patch 
>> > >>> to
>> > >>> include/xen/interface/io/ring.h which is not required for 
>> > >>> xen/stable-2.6.32.x.
>> > >>> I haven't tested the xen/stable-2.6.32.x kernel though.
>> > >>>
>> > >>
>> > >> Great, thanks!
>> > >> Is it OK to forward this email to xen-devel mailinglist?
>> > >>
>> > >> Btw did you check from novell's kernel git tree if there
>> > >> has been fixes to the pvusb code after that patch on
>> > >> code.google.com was posted?
>> > >>
>> > >> -- Pasi
>> > >
>> > > For sure, you're welcome to forward it, but maybe hold off a bit because
>> > > I've refactored the pvusb frontend code to be consistent with the way the
>> > > other frontend drivers are within the pvops tree. I'll also take a look 
>> > > at
>> > > Novell's tree to check for updates.
>> > >
>> > > I'll do some testing on a kernel built from the pvops stable-2.6.32.x 
>> > > tree
>> > > and send an updated diff against that tree in the next couple of days.
>> > >
>> > > Nathanael
>> > >
>> >
>> > I've attached an updated diff against the pvops xen/stable-2.6.32.x tree.
>> > I've tested by attaching an af9015 USB TV tuner to a pvops domu from
>> > a pvops dom0 and recording a few hours of TV.
>> >
>> > I also tried to attach various USB devices to a WinXP domu with GPLPV
>> > drivers, but the domu kept crashing. That needs more investigation, but
>> > I suspect a problem with the GPLPV drivers. I'm keen for that to be fixed,
>> > but I don't have time immediately to dig into it.
>> >
>> > I took a look at the patches at
>> > http://gitorious.org/opensuse/kernel-source/trees/SLE11-SP1/patches.xen
>> > and as far as I can tell, everything that relates to pvusb is included in 
>> > the
>> > attached patch.
>> >
>> > Nathanael
>> >
>> >
>> >
>> > ----- End forwarded message -----
>>
>>
>

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