Re: [PATCH v5 0/7] Add virtio-iommu driver

[Auger Eric <eric.auger@redhat.com>]

Hi Michael,

On 11/27/18 5:53 PM, Michael S. Tsirkin wrote:
> On Thu, Nov 22, 2018 at 07:37:54PM +0000, Jean-Philippe Brucker wrote:
>> Implement the virtio-iommu driver, following specification v0.9 [1].
>>
>> Since v4 [2] I fixed the issues reported by Eric, and added Reviewed-by
>> from Eric and Rob. Thanks!
>>
>> I changed the specification to fix one inconsistency discussed in v4.
>> That the device fills the probe buffer with zeroes is now a "SHOULD"
>> instead of a "MAY", since it's the only way for the driver to know if
>> the device wrote the status. Existing devices already do this. In
>> addition the device now needs to fill the three padding bytes at the
>> tail with zeroes.
>>
>> You can find Linux driver and kvmtool device on branches
>> virtio-iommu/v0.9 [3]. I also lightly tested with Eric's latest QEMU
>> device [4].
> 
> I tried to get this to work on my x86 box but without
> success. Any hints? Does this have to do with the IORT table?
> I think we really should just reserve our own table ID
> and avoid the pain of trying to add things to the IORT spec.
> I'm reluctant to merge lots of code that I can't easily test.
> Again, if we found a way to push more configuration into
> virtio config space the problem space would be smaller.

You can at least test it with QEMU ARM virt in TCG mode. Then I have
worked on the IORT integration in PC/Q35 but this is not yet functional.
I need to debug what's wrong on guest ACPI probing. I plan to work on
this this week.

Thanks

Eric
> 
>> [1] Virtio-iommu specification v0.9, sources, pdf and diff from v0.8
>>     git://linux-arm.org/virtio-iommu.git virtio-iommu/v0.9
>>     http://jpbrucker.net/virtio-iommu/spec/v0.9/virtio-iommu-v0.9.pdf
>>     http://jpbrucker.net/virtio-iommu/spec/diffs/virtio-iommu-pdf-diff-v0.8-v0.9.pdf
>>
>> [2] [PATCH v4 0/7] Add virtio-iommu driver
>>     https://lists.linuxfoundation.org/pipermail/iommu/2018-November/031074.html
>>
>> [3] git://linux-arm.org/linux-jpb.git virtio-iommu/v0.9
>>     git://linux-arm.org/kvmtool-jpb.git virtio-iommu/v0.9
>>
>> [4] [RFC v9 00/17] VIRTIO-IOMMU device
>>     https://www.mail-archive.com/qemu-devel@nongnu.org/msg575578.html
>>
>> Jean-Philippe Brucker (7):
>>   dt-bindings: virtio-mmio: Add IOMMU description
>>   dt-bindings: virtio: Add virtio-pci-iommu node
>>   of: Allow the iommu-map property to omit untranslated devices
>>   PCI: OF: Initialize dev->fwnode appropriately
>>   iommu: Add virtio-iommu driver
>>   iommu/virtio: Add probe request
>>   iommu/virtio: Add event queue
>>
>>  .../devicetree/bindings/virtio/iommu.txt      |   66 +
>>  .../devicetree/bindings/virtio/mmio.txt       |   30 +
>>  MAINTAINERS                                   |    7 +
>>  drivers/iommu/Kconfig                         |   11 +
>>  drivers/iommu/Makefile                        |    1 +
>>  drivers/iommu/virtio-iommu.c                  | 1157 +++++++++++++++++
>>  drivers/of/base.c                             |   10 +-
>>  drivers/pci/of.c                              |    7 +
>>  include/uapi/linux/virtio_ids.h               |    1 +
>>  include/uapi/linux/virtio_iommu.h             |  161 +++
>>  10 files changed, 1448 insertions(+), 3 deletions(-)
>>  create mode 100644 Documentation/devicetree/bindings/virtio/iommu.txt
>>  create mode 100644 drivers/iommu/virtio-iommu.c
>>  create mode 100644 include/uapi/linux/virtio_iommu.h
>>
>> -- 
>> 2.19.1