Re: [PATCH v1 2/6] dt-bindings: hypervisor: Add binding for MediaTek GenieZone hypervisor

["Yi-De Wu (吳一德)" <Yi-De.Wu@mediatek.com>]

On Fri, 2023-04-14 at 17:29 +0200, Matthias Brugger wrote:
> External email : Please do not click links or open attachments until
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> 
> On 14/04/2023 10:35, Yi-De Wu (吳一德) wrote:
> > On Thu, 2023-04-13 at 15:05 +0200, Krzysztof Kozlowski wrote:
> > > External email : Please do not click links or open attachments
> > > until
> > > you have verified the sender or the content.
> > > 
> > > 
> > > On 13/04/2023 11:07, Yi-De Wu wrote:
> > > > From: "Yingshiuan Pan" <yingshiuan.pan@mediatek.com>
> > > > 
> > > > Add documentation for GenieZone(gzvm) node. This node informs
> > > > gzvm
> > > > driver to start probing if geniezone hypervisor is available
> > > > and
> > > 
> > > Subject: drop second/last, redundant "binding for". The "dt-
> > > bindings"
> > > prefix is already stating that these are bindings.
> > > 
> > 
> > Thank you for the review comments. We would remove the "binding
> > for"
> > wording in the subject on the next version.
> > 
> > > > able to do virtual machine operations.
> > > > 
> > > > Signed-off-by: Yingshiuan Pan <yingshiuan.pan@mediatek.com>
> > > > Signed-off-by: Yi-De Wu <yi-de.wu@mediatek.com>
> > > > ---
> > > >   .../bindings/hypervisor/mediatek,gzvm.yaml    | 30
> > > > +++++++++++++++++++
> > > >   1 file changed, 30 insertions(+)
> > > >   create mode 100644
> > > > Documentation/devicetree/bindings/hypervisor/mediatek,gzvm.yaml
> > > > 
> > > > diff --git
> > > > a/Documentation/devicetree/bindings/hypervisor/mediatek,gzvm.ya
> > > > ml
> > > > b/Documentation/devicetree/bindings/hypervisor/mediatek,gzvm.ya
> > > > ml
> > > > new file mode 100644
> > > > index 000000000000..35e1e5b18e47
> > > > --- /dev/null
> > > > +++
> > > > b/Documentation/devicetree/bindings/hypervisor/mediatek,gzvm.ya
> > > > ml
> > > > @@ -0,0 +1,30 @@
> > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > +%YAML 1.2
> > > > +---
> > > > +$id:
> > > > 
https://urldefense.com/v3/__http://devicetree.org/schemas/hypervisor/mediatek,gzvm.yaml*__;Iw!!CTRNKA9wMg0ARbw!lp4d4WBp26cpOeEGcKn_aHcNGfyl1Y--BYzfR8oR_0Xzr9TLvUELfOQAAdqHlLIOra1W_QdjVSJv0-HMpLesJmA3TPJSag$
> > > > +$schema:
> > > > 
https://urldefense.com/v3/__http://devicetree.org/meta-schemas/core.yaml*__;Iw!!CTRNKA9wMg0ARbw!lp4d4WBp26cpOeEGcKn_aHcNGfyl1Y--BYzfR8oR_0Xzr9TLvUELfOQAAdqHlLIOra1W_QdjVSJv0-HMpLesJmDSXil_Qw$
> > > > +
> > > > +title: MediaTek GenieZone hypervisor
> > > > +
> > > > +maintainers:
> > > > +  - Yingshiuan Pan <yingshiuan.pan@mediatek.com>
> > > > +
> > > > +description:
> > > > +  GenieZone is MediaTek proprietary hypervisor. This device
> > > > node
> > > > informs its
> > > > +  driver, gzvm, to probe if platform supports running virtual
> > > > machines.
> > > 
> > > Do not describe Linux, we all know how driver binding works, but
> > > hardware/firmware/hypervisor.
> > > 
> > 
> > Noted. We would enhance the description on next version.
> > 
> > > I don't know if we actually want to support proprietary
> > > hypervisors.
> > > There can be hundreds of them, one per each SoC manufacturer, and
> > > they
> > > can come with many ridiculous ideas.
> > > 
> > 
> > MediaTek, as a partner of Android, our GenieZone hypervisor has
> > been
> > one of the backend options under Android Virtualization
> > Framework(AVF)
> > now.
> > Thus, we'd like to donate these patches for better supporting the
> > Linux/Android ecosystem.
> > 
> > Reference link: 
> > https://urldefense.com/v3/__https://crosvm.dev/book/hypervisors.html*geniezone__;Iw!!CTRNKA9wMg0ARbw!n1sN15eKnG1M6mlcAb7UBi4hoIYmKsw2zlfdwO21thuHZuHYHHkHnZF9WWfp3xScXVha3mlbLVCUMGIo3OM6D8eI$
> > 
> 
> What is the difference between geniezone and gunyah? Why will we need
> both of
> them? Couldn't we just get one hypervisor implementation merged that
> includes
> all the needed features. In the end it will be used with the same
> VMM.
> 
> Regards,
> Matthias
> 

We might not be able to speak for Gunyah, but Gunyah and GenieZone are
quite different hypervisor implementations in various aspects such like
VM execution flow, semantics, UAPI...etc.

Still, we're open to dicussion if there's any proposal that provide a
unified interface among all the hypervisors.

> > > > +
> > > > +properties:
> > > > +  compatible:
> > > > +    const: mediatek,gzvm
> > > > +
> > > > +required:
> > > > +  - compatible
> > > > +
> > > > +additionalProperties: false
> > > > +
> > > > +examples:
> > > > +  - |
> > > > +    hypervisor {
> > > > +        compatible = "mediatek,gzvm";
> > > > +        status = "okay";
> > > 
> > > Drop status.
> > > 
> > > Best regards,
> > > Krzysztof
> > >