On 17.05.22 03:27, Rob Herring wrote:
Hello Rob, all
On Sat, May 07, 2022 at 09:19:06PM +0300, Oleksandr Tyshchenko wrote:
From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
Introduce Xen specific binding for the virtualized device (e.g. virtio)
to be used by Xen grant DMA-mapping layer in the subsequent commit.
This binding indicates that Xen grant mappings scheme needs to be
enabled for the device which DT node contains that property and specifies
the ID of Xen domain where the corresponding backend resides. The ID
(domid) is used as an argument to the 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@xxxxxxxx>
---
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
---
.../devicetree/bindings/arm/xen,dev-domid.yaml | 37 ++++++++++++++++++++++
Documentation/devicetree/bindings/virtio/mmio.yaml | 7 ++++
2 files changed, 44 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/xen,dev-domid.yaml
diff --git a/Documentation/devicetree/bindings/arm/xen,dev-domid.yaml b/Documentation/devicetree/bindings/arm/xen,dev-domid.yaml
new file mode 100644
index 00000000..750e89e
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/xen,dev-domid.yaml
@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/xen,dev-domid.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Xen specific binding for virtualized devices (e.g. virtio)
+
+maintainers:
+ - Stefano Stabellini <sstabellini@xxxxxxxxxx>
+
+select: true
Omit. No need to apply this on every single node.
ok, will do
+
+description:
+ This binding indicates that Xen grant mappings need to be enabled for
+ the device, and it specifies the ID of the domain where the corresponding
+ device (backend) resides. The property is required to restrict memory
+ access using Xen grant mappings.
+
+properties:
+ xen,dev-domid:
I kind of think 'dev' is redundant. Is there another kind of domid
possible?
In general, yes. It is driver(frontend) domid. But, at least for now, I
don't see why we will need an additional property for that.
Maybe xen,backend-domid or just xen,domid? I don't know Xen
too well, so ultimately up to you all.
xen,domid sounds ambiguous to me.
xen,backend-domid sounds perfectly fine to me, I even think it fits better.
Stefano, Juergen, would you be happy with new xen,backend-domid name?
If yes, Stefano could you please clarify, would you be OK if I retained
your R-b tags (for all patches in current series which touch that
property) after doing such renaming?
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description:
+ The domid (domain ID) of the domain where the device (backend) is running.
+
+additionalProperties: true
+
+examples:
+ - |
+ virtio@3000 {
+ compatible = "virtio,mmio";
+ reg = <0x3000 0x100>;
+ interrupts = <41>;
+
+ /* The device is located in Xen domain with ID 1 */
+ xen,dev-domid = <1>;
+ };
diff --git a/Documentation/devicetree/bindings/virtio/mmio.yaml b/Documentation/devicetree/bindings/virtio/mmio.yaml
index 10c22b5..29a0932 100644
--- a/Documentation/devicetree/bindings/virtio/mmio.yaml
+++ b/Documentation/devicetree/bindings/virtio/mmio.yaml
@@ -13,6 +13,9 @@ description:
See https://www.oasis-open.org/committees/tc_home.php?wg_abbrev=virtio for
more details.
+allOf:
+ - $ref: /schemas/arm/xen,dev-domid.yaml#
+
properties:
compatible:
const: virtio,mmio
@@ -33,6 +36,10 @@ properties:
description: Required for devices making accesses thru an IOMMU.
maxItems: 1
+ xen,dev-domid:
+ description: Required when Xen grant mappings need to be enabled for device.
+ $ref: /schemas/types.yaml#/definitions/uint32
No need to define the type again nor describe it again.
Instead, just change additionalProperties to unevaluateProperties in
this doc. The diff is the latter takes $ref's into account.
ok, will do. Could you please clarify, shall I use?
unevaluatedProperties: false
or
unevaluatedProperties:
type: object
I am not too familiar with this stuff. Both variants seem to pass
validation.
Thank you.
+
required:
- compatible
- reg
--
2.7.4
--
Regards,
Oleksandr Tyshchenko
