Re: Xen "pvhvm" driver support for squeeze?
On Wed, 2010-07-28 at 03:43 +0100, Ben Hutchings wrote:
> On Tue, 2010-07-27 at 15:44 +0100, Ian Campbell wrote:
> > The pvhvm drivers for Xen allow a fully virtualised guest (aka HVM) to
> > use the Xen PV disk and network interfaces the same as a Xen guest
> > running paravirtualised, in addition they allow for PV time and event
> > delivery, suspend/resume support and PV hooks to improve performance
> > under shadow page tables.
> >
> > The drivers are currently in linux-next and are expected to go in during
> > the next merge window. Stefano (the upstream author) has also prepared
> > backports to 2.6.32 for RHEL6 and I would like to know if there would be
> > interest in (or rather objections to) my adding these to the squeeze
> > kernel?
>
> This looks OK in principle.
>
> > The majority of the patch is a new driver for a virtual PCI device which
> > provides the glue to allow the existing PV drivers to work in an HVM
> > context.
>
> One nit is that you are adding to <linux/pci_ids.h> which is deprecated
> now. You should just define the vendor/device IDs in the driver.
I didn't know that, it looks like the file is still being updated fairly
regularly. I guess it should have come up in review of the upstream
version?
> > The diffstat (below vs 2.6.32) is a bit daunting but really it is just
> > some infrastructure hooks and the new "platform-pci" driver. The
> > functionality is also rather modular so it would be possible e.g. to
> > just have PV disk and network but not time etc etc.
> >
> > The full series of patches can be found at
> > http://xenbits.xensource.com/gitweb?p=people/sstabellini/linux-pvhvm.git
> > in the branch 2.6.32-pvhvm
> >
> > Opinions?
>
> I note that the backport branch was only created today, so I'm guessing
> it hasn't had a whole lot of testing yet.
I'm sure Stefano will correct me if I'm wrong but I think the majority
of the patch series was actually developed against the stable-2.6.32.x
branch in the xen.git tree and then forward ported to a more recent
version for upstreaming. The 2.6.32-pvhvm is a rebase to plain 2.6.32,
so it's relatively well tested, as new branches go ;-)
Stefano, I actually had to rebase again onto 2.6.32.16 (which is
currently the Debian base version) to resolve a few conflicts.
> Can we put off this decision for a week or so, so you and your
> colleagues have time to test the backport branch and we can also see
> Linus's decision on whether to pull the changes into 2.6.36?
Sure, that seems reasonable.
Ian.
--
Ian Campbell
Current Noise: Tool - Eulogy
Yow! It's some people inside the wall! This is better than mopping!
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