| Message ID | 1654197833-25362-6-git-send-email-olekstysh@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | virtio: Solution to restrict memory access under Xen using xen-grant DMA-mapping layer | expand |
On Thu, 02 Jun 2022 22:23:50 +0300, Oleksandr Tyshchenko wrote: > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > > The main purpose of this binding is to communicate Xen specific > information using generic IOMMU device tree bindings (which is > a good fit here) rather than introducing a custom property. > > Introduce Xen specific IOMMU for the virtualized device (e.g. virtio) > to be used by Xen grant DMA-mapping layer in the subsequent commit. > > The reference to Xen specific IOMMU node using "iommus" property > indicates that Xen grant mappings need to be enabled for the device, > and it specifies the ID of the domain where the corresponding backend > resides. The domid (domain ID) is used as an argument to the Xen grant > mapping APIs. > > This is needed for the option to restrict memory access using Xen grant > mappings to work which primary goal is to enable using virtio devices > in Xen guests. > > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > --- > Changes RFC -> V1: > - update commit subject/description and text in description > - move to devicetree/bindings/arm/ > > Changes V1 -> V2: > - update text in description > - change the maintainer of the binding > - fix validation issue > - reference xen,dev-domid.yaml schema from virtio/mmio.yaml > > Change V2 -> V3: > - Stefano already gave his Reviewed-by, I dropped it due to the changes (significant) > - use generic IOMMU device tree bindings instead of custom property > "xen,dev-domid" > - change commit subject and description, was > "dt-bindings: Add xen,dev-domid property description for xen-grant DMA ops" > > Changes V3 -> V4: > - add Stefano's R-b > - remove underscore in iommu node name > - remove consumer example virtio@3000 > - update text for two descriptions > --- > .../devicetree/bindings/iommu/xen,grant-dma.yaml | 39 ++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > create mode 100644 Documentation/devicetree/bindings/iommu/xen,grant-dma.yaml > Reviewed-by: Rob Herring <robh@kernel.org>
diff --git a/Documentation/devicetree/bindings/iommu/xen,grant-dma.yaml b/Documentation/devicetree/bindings/iommu/xen,grant-dma.yaml new file mode 100644 index 00000000..be1539d --- /dev/null +++ b/Documentation/devicetree/bindings/iommu/xen,grant-dma.yaml @@ -0,0 +1,39 @@ +# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/iommu/xen,grant-dma.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Xen specific IOMMU for virtualized devices (e.g. virtio) + +maintainers: + - Stefano Stabellini <sstabellini@kernel.org> + +description: + The Xen IOMMU represents the Xen grant table interface. Grant mappings + are to be used with devices connected to the Xen IOMMU using the "iommus" + property, which also specifies the ID of the backend domain. + The binding is required to restrict memory access using Xen grant mappings. + +properties: + compatible: + const: xen,grant-dma + + '#iommu-cells': + const: 1 + description: + The single cell is the domid (domain ID) of the domain where the backend + is running. + +required: + - compatible + - "#iommu-cells" + +additionalProperties: false + +examples: + - | + iommu { + compatible = "xen,grant-dma"; + #iommu-cells = <1>; + };