Re: [PATCH v6 0/7] Add virtio-iommu driver

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Dec 13, 2018 at 12:50:29PM +0000, Jean-Philippe Brucker wrote:
> >> [3] git://linux-arm.org/linux-jpb.git virtio-iommu/v0.9.1
> >>     git://linux-arm.org/kvmtool-jpb.git virtio-iommu/v0.9
> > 
> > Unfortunatly gitweb seems to be broken on linux-arm.org. What is missing
> > in this patch-set to make this work on x86?
> 
> You should be able to access it here:
> http://www.linux-arm.org/git?p=linux-jpb.git;a=shortlog;h=refs/heads/virtio-iommu/devel
> 
> That branch contains missing bits for x86 support:
> 
> * ACPI support. We have the code but it's waiting for an IORT spec
> update, to reserve the IORT node ID. I expect it to take a while, given
> that I'm alone requesting a change for something that's not upstream or
> in hardware.

Frankly I think you should take a hard look at just getting the data
needed from the PCI device itself.  You don't need to depend on virtio,
it can be a small driver that gets you that data from the device config
space and then just goes away.

If you want help with writing such a small driver let me know.

If there's an advantage to virtio-iommu then that would be its
portability, and it all goes out of the window because
of dependencies on ACPI and DT and OF and the rest of the zoo.


> * DMA ops for x86 (see "HACK" commit). I'd like to use dma-iommu but I'm
> not sure how to implement the glue that sets dma_ops properly.
> 
> Thanks,
> Jean

OK so IIUC you are looking into Christoph's suggestions to fix that up?

There's still a bit of time left before the merge window,
maybe you can make above changes.

-- 
MST