| Message ID | 20181012145917.6840-3-jean-philippe.brucker@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | Add virtio-iommu driver | expand |
On Fri, 12 Oct 2018 15:59:12 +0100, Jean-Philippe Brucker wrote: > Some systems implement virtio-iommu as a PCI endpoint. The operating > systems needs to discover the relationship between IOMMU and masters long > before the PCI endpoint gets probed. Add a PCI child node to describe the > virtio-iommu device. > > The virtio-pci-iommu is conceptually split between a PCI programming > interface and a translation component on the parent bus. The latter > doesn't have a node in the device tree. The virtio-pci-iommu node > describes both, by linking the PCI endpoint to "iommus" property of DMA > master nodes and to "iommu-map" properties of bus nodes. > > Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> > --- > .../devicetree/bindings/virtio/iommu.txt | 66 +++++++++++++++++++ > 1 file changed, 66 insertions(+) > create mode 100644 Documentation/devicetree/bindings/virtio/iommu.txt > Reviewed-by: Rob Herring <robh@kernel.org>
Hi Jean, On 10/12/18 4:59 PM, Jean-Philippe Brucker wrote: > Some systems implement virtio-iommu as a PCI endpoint. The operating > systems needs to discover the relationship between IOMMU and masters long s/systems/system > before the PCI endpoint gets probed. Add a PCI child node to describe the > virtio-iommu device. > > The virtio-pci-iommu is conceptually split between a PCI programming > interface and a translation component on the parent bus. The latter > doesn't have a node in the device tree. The virtio-pci-iommu node > describes both, by linking the PCI endpoint to "iommus" property of DMA > master nodes and to "iommu-map" properties of bus nodes. > > Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> > --- > .../devicetree/bindings/virtio/iommu.txt | 66 +++++++++++++++++++ > 1 file changed, 66 insertions(+) > create mode 100644 Documentation/devicetree/bindings/virtio/iommu.txt > > diff --git a/Documentation/devicetree/bindings/virtio/iommu.txt b/Documentation/devicetree/bindings/virtio/iommu.txt > new file mode 100644 > index 000000000000..2407fea0651c > --- /dev/null > +++ b/Documentation/devicetree/bindings/virtio/iommu.txt > @@ -0,0 +1,66 @@ > +* virtio IOMMU PCI device > + > +When virtio-iommu uses the PCI transport, its programming interface is > +discovered dynamically by the PCI probing infrastructure. However the > +device tree statically describes the relation between IOMMU and DMA > +masters. Therefore, the PCI root complex that hosts the virtio-iommu > +contains a child node representing the IOMMU device explicitly. > + > +Required properties: > + > +- compatible: Should be "virtio,pci-iommu" > +- reg: PCI address of the IOMMU. As defined in the PCI Bus > + Binding reference [1], the reg property is a five-cell > + address encoded as (phys.hi phys.mid phys.lo size.hi > + size.lo). phys.hi should contain the device's BDF as > + 0b00000000 bbbbbbbb dddddfff 00000000. The other cells > + should be zero. > +- #iommu-cells: Each platform DMA master managed by the IOMMU is assigned > + an endpoint ID, described by the "iommus" property [2]. > + For virtio-iommu, #iommu-cells must be 1. > + > +Notes: > + > +- DMA from the IOMMU device isn't managed by another IOMMU. Therefore the > + virtio-iommu node doesn't have an "iommus" property, and is omitted from > + the iommu-map property of the root complex. > + > +Example: > + > +pcie@10000000 { > + compatible = "pci-host-ecam-generic"; > + ... > + > + /* The IOMMU programming interface uses slot 00:01.0 */ > + iommu0: iommu@0008 { > + compatible = "virtio,pci-iommu"; > + reg = <0x00000800 0 0 0 0>; > + #iommu-cells = <1>; > + }; > + > + /* > + * The IOMMU manages all functions in this PCI domain except > + * itself. Omit BDF 00:01.0. > + */ > + iommu-map = <0x0 &iommu0 0x0 0x8> > + <0x9 &iommu0 0x9 0xfff7>; > +}; > + > +pcie@20000000 { > + compatible = "pci-host-ecam-generic"; > + ... > + /* > + * The IOMMU also manages all functions from this domain, > + * with endpoint IDs 0x10000 - 0x1ffff > + */ > + iommu-map = <0x0 &iommu0 0x10000 0x10000>; > +}; > + > +ethernet@fe001000 { > + ... > + /* The IOMMU manages this platform device with endpoint ID 0x20000 */ > + iommus = <&iommu0 0x20000>; > +}; > + > +[1] Documentation/devicetree/bindings/pci/pci.txt > +[2] Documentation/devicetree/bindings/iommu/iommu.txt Reviewed-by: Eric Auger <eric.auger@redhat.com> Thanks Eric >
diff --git a/Documentation/devicetree/bindings/virtio/iommu.txt b/Documentation/devicetree/bindings/virtio/iommu.txt new file mode 100644 index 000000000000..2407fea0651c --- /dev/null +++ b/Documentation/devicetree/bindings/virtio/iommu.txt @@ -0,0 +1,66 @@ +* virtio IOMMU PCI device + +When virtio-iommu uses the PCI transport, its programming interface is +discovered dynamically by the PCI probing infrastructure. However the +device tree statically describes the relation between IOMMU and DMA +masters. Therefore, the PCI root complex that hosts the virtio-iommu +contains a child node representing the IOMMU device explicitly. + +Required properties: + +- compatible: Should be "virtio,pci-iommu" +- reg: PCI address of the IOMMU. As defined in the PCI Bus + Binding reference [1], the reg property is a five-cell + address encoded as (phys.hi phys.mid phys.lo size.hi + size.lo). phys.hi should contain the device's BDF as + 0b00000000 bbbbbbbb dddddfff 00000000. The other cells + should be zero. +- #iommu-cells: Each platform DMA master managed by the IOMMU is assigned + an endpoint ID, described by the "iommus" property [2]. + For virtio-iommu, #iommu-cells must be 1. + +Notes: + +- DMA from the IOMMU device isn't managed by another IOMMU. Therefore the + virtio-iommu node doesn't have an "iommus" property, and is omitted from + the iommu-map property of the root complex. + +Example: + +pcie@10000000 { + compatible = "pci-host-ecam-generic"; + ... + + /* The IOMMU programming interface uses slot 00:01.0 */ + iommu0: iommu@0008 { + compatible = "virtio,pci-iommu"; + reg = <0x00000800 0 0 0 0>; + #iommu-cells = <1>; + }; + + /* + * The IOMMU manages all functions in this PCI domain except + * itself. Omit BDF 00:01.0. + */ + iommu-map = <0x0 &iommu0 0x0 0x8> + <0x9 &iommu0 0x9 0xfff7>; +}; + +pcie@20000000 { + compatible = "pci-host-ecam-generic"; + ... + /* + * The IOMMU also manages all functions from this domain, + * with endpoint IDs 0x10000 - 0x1ffff + */ + iommu-map = <0x0 &iommu0 0x10000 0x10000>; +}; + +ethernet@fe001000 { + ... + /* The IOMMU manages this platform device with endpoint ID 0x20000 */ + iommus = <&iommu0 0x20000>; +}; + +[1] Documentation/devicetree/bindings/pci/pci.txt +[2] Documentation/devicetree/bindings/iommu/iommu.txt
Some systems implement virtio-iommu as a PCI endpoint. The operating systems needs to discover the relationship between IOMMU and masters long before the PCI endpoint gets probed. Add a PCI child node to describe the virtio-iommu device. The virtio-pci-iommu is conceptually split between a PCI programming interface and a translation component on the parent bus. The latter doesn't have a node in the device tree. The virtio-pci-iommu node describes both, by linking the PCI endpoint to "iommus" property of DMA master nodes and to "iommu-map" properties of bus nodes. Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> --- .../devicetree/bindings/virtio/iommu.txt | 66 +++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 Documentation/devicetree/bindings/virtio/iommu.txt