Re: [Qemu-devel] [PATCH 0/3] VFIO-based PCI device assignment for QEMU 1.2

[Alex Williamson <alex.williamson@redhat.com>]

On Mon, 2012-08-13 at 08:27 -0500, Anthony Liguori wrote:
> Alex Williamson <alex.williamson@redhat.com> writes:
> 
> > VFIO kernel support was just merged into Linux, so I'd like to
> > formally propose inclusion of the QEMU vfio-pci driver for
> > QEMU 1.2.  Included here is support for x86 PCI device assignment.
> > PCI INTx is not yet enabled, but devices making use of either MSI
> > or MSI-X work.  The level irqfd and eoifd support I've proposed
> > for KVM enable an accelerated patch for this through KVM.  I'd
> > like to get this base driver in first and enable the remaining
> > support in-tree.
> >
> > I've split this version up a little from the RFC to make it a bit
> > easier to review.  Review comments from Blue Swirl and Avi are
> > already incorporated, including Avi's requests to simplify both
> > the PCI BAR mapping and unmapping paths.
> 
> Hi Alex,
> 
> Thanks for pushing this forward!  Hopefully this will finally kill off
> qemu-kvm.git for good.
> 
> I think this series is going to have to wait for 1.3 to open up.  We
> have a very short release window for this release and I'd feel a lot
> more comfortable having such a significant feature spend some time in
> the development cycle getting testing/review.
> 
> I'd like to see a few Reviewed-by's too for this series before it goes
> in.  I expect they won't be hard to get but I also expect it will take a
> few more revisions of this series to get there.

That's disappointing, but I can understand your reluctance.  Blue Swirl
reviewed the RFC and could perhaps add a Reviewed-by.  Alexey has been
working on the POWER port and I'm sure could provide a Reviewed-by.  We
also have a few early adopters that are already making use of this code.
Towards accepting it, the driver is entirely self contained, there's
really no risk to the rest of qemu.  The only missing functionality is
legacy interrupt support.  Perhaps there's a compromise where this
driver could be considered a tech preview in 1.2 (x-vfio-pci?).  Thanks,

Alex