Hi Jean, On 10/12/18 4:59 PM, Jean-Philippe Brucker wrote: > Implement the virtio-iommu driver, following specification v0.8 [1]. > Changes since v2 [2]: > > * Patches 2-4 allow virtio-iommu to use the PCI transport, since QEMU > would like to phase out the MMIO transport. This produces a complex > topology where the programming interface of the IOMMU could appear > lower than the endpoints that it translates. It's not unheard of (e.g. > AMD IOMMU), and the guest easily copes with this. > > The "Firmware description" section of the specification has been > updated with all combinations of PCI, MMIO and DT, ACPI. I have a question wrt the FW specification. The IOMMU consumes 1 slot in the PCI domain and one needs to leave a RID hole in the iommu-map. It is not obvious to me that this RID always is predictable given the pcie enumeration mechanism. Generally we have a coarse grain mapping of RID onto iommu phandles/STREAMIDs. Here, if I understand correctly we need to precisely identify the RID granted to the iommu. On QEMU this may depend on the instantiation order of the virtio-pci device right? So this does not look trivial to build this info. Isn't it possible to do this exclusion at kernel level instead? Thanks Eric > > * Fix structures layout, they don't need the "packed" attribute anymore. > > * While we're at it, add domain parameter to DETACH request, and leave > some padding. This way the next version, that adds PASID support, > won't have to introduce a "DETACH2" request to stay backward > compatible. > > * Require virtio device 1.0+. Remove legacy transport notes from the > specification. > > * Request timeout is now only enabled with DEBUG. > > * The patch for VFIO Kconfig (previously patch 5/5) is in next. > > You can find Linux driver and kvmtool device on branches > virtio-iommu/v0.8 [3] (currently based on 4.19-rc7 but rebasing onto > next only produced a trivial conflict). Branch virtio-iommu/devel > contains a few patches that I'd like to send once the base is upstream: > > * virtio-iommu as a module. It got *much* nicer after Rob's probe > deferral rework, but I still have a bug to fix when re-loading the > virtio-iommu module. > > * ACPI support requires a minor IORT spec update (reservation of node > ID). I think it should be easier to obtain once the device and drivers > are upstream. > > [1] Virtio-iommu specification v0.8, diff from v0.7, and sources > git://linux-arm.org/virtio-iommu.git virtio-iommu/v0.8 > http://jpbrucker.net/virtio-iommu/spec/v0.8/virtio-iommu-v0.8.pdf > http://jpbrucker.net/virtio-iommu/spec/diffs/virtio-iommu-pdf-diff-v0.7-v0.8.pdf > > [2] [PATCH v2 0/5] Add virtio-iommu driver > https://www.spinics.net/lists/kvm/msg170655.html > > [3] git://linux-arm.org/linux-jpb.git virtio-iommu/v0.8 > git://linux-arm.org/kvmtool-jpb.git virtio-iommu/v0.8 > > Jean-Philippe Brucker (7): > dt-bindings: virtio-mmio: Add IOMMU description > dt-bindings: virtio: Add virtio-pci-iommu node > PCI: OF: allow endpoints to bypass the iommu > 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 | 1171 +++++++++++++++++ > drivers/pci/of.c | 14 +- > include/uapi/linux/virtio_ids.h | 1 + > include/uapi/linux/virtio_iommu.h | 159 +++ > 9 files changed, 1457 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 >
