Re: [RFC PATCH 3/6] dt-bindings: xen: Add xen,dev-domid property description for xen-virtio layer

Oleksandr
2022-04-17T17:24:17Z

On 16.04.22 01:01, Stefano Stabellini wrote:

Hello Stefano

> On Thu, 14 Apr 2022, Oleksandr Tyshchenko wrote:
>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>
>> Introduce Xen specific binding for the virtio-mmio device to be used
>> by Xen virtio support driver in a subsequent commit.
>>
>> This binding specifies the ID of Xen domain where the corresponding
>> device (backend) resides. This is needed for the option to restrict
>> memory access using Xen grant mappings to work.
>>
>> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>> ---
>> .../devicetree/bindings/virtio/xen,dev-domid.yaml | 39 ++++++++++++++++++++++
>> 1 file changed, 39 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/virtio/xen,dev-domid.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/virtio/xen,dev-domid.yaml b/Documentation/devicetree/bindings/virtio/xen,dev-domid.yaml
>> new file mode 100644
>> index 00000000..78be993
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/virtio/xen,dev-domid.yaml
>> @@ -0,0 +1,39 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/virtio/xen,dev-domid.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Xen specific binding for the virtio device
>> +
>> +maintainers:
>> + - Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>> +
>> +select: true
>> +
>> +description:
>> + This binding specifies the ID of Xen domain where the corresponding device
>> + (backend) resides. This is needed for the option to restrict memory access
>> + using Xen grant mappings to work.
>> +
>> + Note that current and generic "iommus" bindings are mutually exclusive, since
>> + the restricted memory access model on Xen behaves as a kind of software IOMMU.
> I don't think that this last statement is necessary or fully accurate, so
> I would remove it.

ok, will remove

> Other than that, this looks good to me.

thank you

>
>
>> +properties:
>> + xen,dev-domid:
>> + $ref: /schemas/types.yaml#/definitions/uint32
>> + description:
>> + Should contain the ID of device's domain.
> Maybe better as:
> "The domid (domain ID) of the domain where the device (backend) is running"

ok, will change

>
>
>
>> +additionalProperties: true
>> +
>> +examples:
>> + - |
>> + virtio_block@3000 {
>> + compatible = "virtio,mmio";
>> + reg = <0x3000 0x100>;
>> + interrupts = <41>;
>> +
>> + /* The device is located in Xen domain with ID 1 */
>> + xen,dev-domid = <1>;
>> + };
>> --
>> 2.7.4
>>
--
Regards,

Oleksandr Tyshchenko