summaryrefslogtreecommitdiffstats
path: root/Documentation/devicetree
diff options
context:
space:
mode:
authorOleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>2022-06-02 22:23:50 +0300
committerJuergen Gross <jgross@suse.com>2022-06-06 16:07:30 +0200
commitadd413a1d966d8458571a2571881903d234a9f8e (patch)
tree14f23c0c6a25e4aa1074fa8e698da92dac25d674 /Documentation/devicetree
parentfa1f57421e0b1c57843902c89728f823abc32f02 (diff)
downloadlinux-add413a1d966d8458571a2571881903d234a9f8e.tar.bz2
dt-bindings: Add xen,grant-dma IOMMU description for xen-grant DMA ops
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> Reviewed-by: Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/1654197833-25362-6-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r--Documentation/devicetree/bindings/iommu/xen,grant-dma.yaml39
1 files changed, 39 insertions, 0 deletions
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 000000000000..be1539d234f9
--- /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>;
+ };