| Message ID | 20250307220304.247725-8-romank@linux.microsoft.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Delegated to: | Krzysztof Wilczyński |
| Headers | show |
| Series | arm64: hyperv: Support Virtual Trust Level Boot | expand |
On Fri, Mar 07, 2025 at 02:02:59PM -0800, Roman Kisel wrote: > To boot on ARM64, VMBus requires configuring interrupts. Missing > DMA coherence property is sub-optimal as the VMBus transations are > cache-coherent. > > Add interrupts to be able to boot on ARM64. Add DMA coherence to > avoid doing extra work on maintaining caches on ARM64. How do you add it? > > Signed-off-by: Roman Kisel <romank@linux.microsoft.com> > --- > .../devicetree/bindings/bus/microsoft,vmbus.yaml | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml > index a8d40c766dcd..3ab7d0116626 100644 > --- a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml > +++ b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml > @@ -28,13 +28,16 @@ properties: > required: > - compatible > - ranges > + - interrupts > - '#address-cells' > - '#size-cells' > > -additionalProperties: false > +additionalProperties: true This is neither explained in commit msg nor correct. Drop the change. You cannot have device bindings ending with 'true' here - see talks, example-bindings, writing-schema and whatever resource is there. Best regards, Krzysztof
On 3/10/2025 2:28 AM, Krzysztof Kozlowski wrote: > On Fri, Mar 07, 2025 at 02:02:59PM -0800, Roman Kisel wrote: >> To boot on ARM64, VMBus requires configuring interrupts. Missing >> DMA coherence property is sub-optimal as the VMBus transations are >> cache-coherent. >> >> Add interrupts to be able to boot on ARM64. Add DMA coherence to >> avoid doing extra work on maintaining caches on ARM64. > > How do you add it? > I added properties to the node. Should I fix the description, or I am misunderstanding the question? >> >> Signed-off-by: Roman Kisel <romank@linux.microsoft.com> >> --- >> .../devicetree/bindings/bus/microsoft,vmbus.yaml | 8 +++++++- >> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml >> index a8d40c766dcd..3ab7d0116626 100644 >> --- a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml >> +++ b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml >> @@ -28,13 +28,16 @@ properties: >> required: >> - compatible >> - ranges >> + - interrupts >> - '#address-cells' >> - '#size-cells' >> >> -additionalProperties: false >> +additionalProperties: true > > This is neither explained in commit msg nor correct. > Not explained, as there is no good explanation as described below. > Drop the change. You cannot have device bindings ending with 'true' > here - see talks, example-bindings, writing-schema and whatever resource > is there. > Thanks, I'll put more effort into bringing this into a better form! If you have time, could you comment on the below? The Documentation says * additionalProperties: true Rare case, used for schemas implementing common set of properties. Such schemas are supposed to be referenced by other schemas, which then use 'unevaluatedProperties: false'. Typically bus or common-part schemas. This is a bus so I added that line to the YAML, and I saw it in many other YAML files. Without that line, there was a warning from the local DT validation described in the Documentation about not having pin controls which was weird, and adding "additionalProperties: true" fixed the warnings (didn't debug much though). As a side note, there was a similar warning coming from another YAML during running DT schema validation as described in the Documentation so maybe warnings are fine. > Best regards, > Krzysztof >
On 10/03/2025 18:05, Roman Kisel wrote: > > > On 3/10/2025 2:28 AM, Krzysztof Kozlowski wrote: >> On Fri, Mar 07, 2025 at 02:02:59PM -0800, Roman Kisel wrote: >>> To boot on ARM64, VMBus requires configuring interrupts. Missing >>> DMA coherence property is sub-optimal as the VMBus transations are >>> cache-coherent. >>> >>> Add interrupts to be able to boot on ARM64. Add DMA coherence to >>> avoid doing extra work on maintaining caches on ARM64. >> >> How do you add it? >> > > I added properties to the node. Should I fix the description, or I am > misunderstanding the question? I saw interrupts in the schema, but I did not see dma-coherence. I also did not see any DTS patches here, so I don't understand what node you are referring to. > >>> >>> Signed-off-by: Roman Kisel <romank@linux.microsoft.com> >>> --- >>> .../devicetree/bindings/bus/microsoft,vmbus.yaml | 8 +++++++- >>> 1 file changed, 7 insertions(+), 1 deletion(-) >>> >>> diff --git a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml >>> index a8d40c766dcd..3ab7d0116626 100644 >>> --- a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml >>> +++ b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml >>> @@ -28,13 +28,16 @@ properties: >>> required: >>> - compatible >>> - ranges >>> + - interrupts >>> - '#address-cells' >>> - '#size-cells' >>> >>> -additionalProperties: false >>> +additionalProperties: true >> >> This is neither explained in commit msg nor correct. >> > > Not explained, as there is no good explanation as described below. > >> Drop the change. You cannot have device bindings ending with 'true' >> here - see talks, example-bindings, writing-schema and whatever resource >> is there. >> > > Thanks, I'll put more effort into bringing this into a better form! > If you have time, could you comment on the below? > > The Documentation says > > * additionalProperties: true > Rare case, used for schemas implementing common set of properties. > Such schemas are supposed to be referenced by other schemas, which then > use 'unevaluatedProperties: false'. Typically bus or common-part schemas. > > This is a bus so I added that line to the YAML, and I saw it in many If this is a bus, then where is schema using it for bus-attached-devices? You cannot have bus without devices. You *must* fulfill that part: "Such schemas are supposed to be referenced by other schemas, which then" instead of calling it bus... Please upstream bindings for the bus devices and extend the example here with these devices. Or this is not bus (calling something vmpony does not make it a pony). Best regards, Krzysztof
On 3/10/2025 10:40 AM, Krzysztof Kozlowski wrote: > On 10/03/2025 18:05, Roman Kisel wrote: >> >> >> On 3/10/2025 2:28 AM, Krzysztof Kozlowski wrote: >>> On Fri, Mar 07, 2025 at 02:02:59PM -0800, Roman Kisel wrote: >>>> To boot on ARM64, VMBus requires configuring interrupts. Missing >>>> DMA coherence property is sub-optimal as the VMBus transations are >>>> cache-coherent. >>>> >>>> Add interrupts to be able to boot on ARM64. Add DMA coherence to >>>> avoid doing extra work on maintaining caches on ARM64. >>> >>> How do you add it? >>> >> >> I added properties to the node. Should I fix the description, or I am >> misunderstanding the question? > > I saw interrupts in the schema, but I did not see dma-coherence. I also > did not see any DTS patches here, so I don't understand what node you > are referring to. > I will refer to talks, example-bindings, writing-schema you've suggested to waste your time less. It appears there is some fundamental flaw in my understanding of how these YAML files work so much so that I cannot even write a commit description that can be understood, for the 5th time in the row, sorry about that. >> >>>> >>>> Signed-off-by: Roman Kisel <romank@linux.microsoft.com> >>>> --- >>>> .../devicetree/bindings/bus/microsoft,vmbus.yaml | 8 +++++++- >>>> 1 file changed, 7 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml >>>> index a8d40c766dcd..3ab7d0116626 100644 >>>> --- a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml >>>> +++ b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml >>>> @@ -28,13 +28,16 @@ properties: >>>> required: >>>> - compatible >>>> - ranges >>>> + - interrupts >>>> - '#address-cells' >>>> - '#size-cells' >>>> >>>> -additionalProperties: false >>>> +additionalProperties: true >>> >>> This is neither explained in commit msg nor correct. >>> >> >> Not explained, as there is no good explanation as described below. >> >>> Drop the change. You cannot have device bindings ending with 'true' >>> here - see talks, example-bindings, writing-schema and whatever resource >>> is there. >>> >> >> Thanks, I'll put more effort into bringing this into a better form! >> If you have time, could you comment on the below? >> >> The Documentation says >> >> * additionalProperties: true >> Rare case, used for schemas implementing common set of properties. >> Such schemas are supposed to be referenced by other schemas, which then >> use 'unevaluatedProperties: false'. Typically bus or common-part schemas. >> >> This is a bus so I added that line to the YAML, and I saw it in many > > If this is a bus, then where is schema using it for > bus-attached-devices? You cannot have bus without devices. > > You *must* fulfill that part: > "Such schemas are supposed to be referenced by other schemas, which then" > > instead of calling it bus... > It is modeled as a bus in the kernel: https://www.kernel.org/doc/html/latest/virt/hyperv/vmbus.html > Please upstream bindings for the bus devices and extend the example here > with these devices. The set of synthetic devices that reside on the bus isn't fixed, and they don't require description neither in ACPI nor in DT as the devices negotiate their MMIO regions through the hyperv driver. Perhaps, it is not as much bus as expected by the YAML files. > > Or this is not bus (calling something vmpony does not make it a pony). > > > Best regards, > Krzysztof
On 10/03/2025 19:07, Roman Kisel wrote: > > It is modeled as a bus in the kernel: > https://www.kernel.org/doc/html/latest/virt/hyperv/vmbus.html > >> Please upstream bindings for the bus devices and extend the example here >> with these devices. > > The set of synthetic devices that reside on the bus isn't fixed, and > they don't require description neither in ACPI nor in DT as > the devices negotiate their MMIO regions through the hyperv driver. > > Perhaps, it is not as much bus as expected by the YAML files. OK, then this is not really a bus from the bindings point of view. It is a device schema which should end with additionalProperties: false. If you have report about that pinctrl-0, it means you have undocumented properties in your DTS. Maybe that's the dma-coherence you mentioned in the commit msg. Best regards, Krzysztof
On 3/10/2025 2:17 PM, Krzysztof Kozlowski wrote: > On 10/03/2025 19:07, Roman Kisel wrote: >> >> It is modeled as a bus in the kernel: >> https://www.kernel.org/doc/html/latest/virt/hyperv/vmbus.html >> >>> Please upstream bindings for the bus devices and extend the example here >>> with these devices. >> >> The set of synthetic devices that reside on the bus isn't fixed, and >> they don't require description neither in ACPI nor in DT as >> the devices negotiate their MMIO regions through the hyperv driver. >> >> Perhaps, it is not as much bus as expected by the YAML files. > > OK, then this is not really a bus from the bindings point of view. It is > a device schema which should end with additionalProperties: false. > > If you have report about that pinctrl-0, it means you have undocumented > properties in your DTS. Maybe that's the dma-coherence you mentioned in > the commit msg. > Much appreciated! I started reviewing the learning materials you mentioned, and I think I already see where my understanding went sideways: I perceived the example as the central part of the bindings whereas it seems to be just what the name suggests: an example. Yet, the example shall conform to the *schema* iiuc, and that is what the tooling validates. Hopefully, I am starting to be getting what this is all about :) Thanks for your help again! I've worked out what makes (more) sense (to me at least): From 475fb74b49dc4987ca8b9117186941d848f0aacd Mon Sep 17 00:00:00 2001 From: Roman Kisel <romank@linux.microsoft.com> Date: Mon, 10 Mar 2025 14:39:41 -0700 Subject: [PATCH] dt-bindings: microsoft,vmbus: Add interrupt and DMA coherence properties To boot in the VTL mode, VMBus on arm64 needs interrupt description which the binding documentation lacks. The transactions on the bus are DMA coherent which is not mentioned as well. Add the interrupt property and the DMA coherence property to the VMBus binding. Update the example to match that. Fix typos. Signed-off-by: Roman Kisel <romank@linux.microsoft.com> --- .../bindings/bus/microsoft,vmbus.yaml | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml index a8d40c766dcd..b175ad01f219 100644 --- a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml +++ b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml @@ -10,8 +10,8 @@ maintainers: - Saurabh Sengar <ssengar@linux.microsoft.com> description: - VMBus is a software bus that implement the protocols for communication - between the root or host OS and guest OSs (virtual machines). + VMBus is a software bus that implements the protocols for communication + between the root or host OS and guest OS'es (virtual machines). properties: compatible: @@ -25,9 +25,17 @@ properties: '#size-cells': const: 1 + dma-coherent: true + + interrupts: + maxItems: 1 + description: | + This interrupt signals a message from the host. + required: - compatible - ranges + - interrupts - '#address-cells' - '#size-cells' @@ -35,6 +43,8 @@ additionalProperties: false examples: - | + #include <dt-bindings/interrupt-controller/irq.h> + #include <dt-bindings/interrupt-controller/arm-gic.h> soc { #address-cells = <2>; #size-cells = <1>; @@ -49,6 +59,9 @@ examples: #address-cells = <2>; #size-cells = <1>; ranges = <0x0f 0xf0000000 0x0f 0xf0000000 0x10000000>; + dma-coherent; + interrupt-parent = <&gic>; + interrupts = <GIC_PPI 2 IRQ_TYPE_EDGE_RISING>; }; }; };
diff --git a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml index a8d40c766dcd..3ab7d0116626 100644 --- a/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml +++ b/Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml @@ -28,13 +28,16 @@ properties: required: - compatible - ranges + - interrupts - '#address-cells' - '#size-cells' -additionalProperties: false +additionalProperties: true examples: - | + #include <dt-bindings/interrupt-controller/irq.h> + #include <dt-bindings/interrupt-controller/arm-gic.h> soc { #address-cells = <2>; #size-cells = <1>; @@ -49,6 +52,9 @@ examples: #address-cells = <2>; #size-cells = <1>; ranges = <0x0f 0xf0000000 0x0f 0xf0000000 0x10000000>; + dma-coherent; + interrupt-parent = <&gic>; + interrupts = <GIC_PPI 2 IRQ_TYPE_EDGE_RISING>; }; }; };
To boot on ARM64, VMBus requires configuring interrupts. Missing DMA coherence property is sub-optimal as the VMBus transations are cache-coherent. Add interrupts to be able to boot on ARM64. Add DMA coherence to avoid doing extra work on maintaining caches on ARM64. Signed-off-by: Roman Kisel <romank@linux.microsoft.com> --- .../devicetree/bindings/bus/microsoft,vmbus.yaml | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)