Re: [PATCH v2 14/17] arm64: dts: realtek: Add EL2 virtual timer interrupt

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Incomplete implementation: missing update for Realtek Kent SoC family which specifies an incorrect EL2 virtual timer interrupt.
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commit 3b73638950a28ecc324e1c28fa4fb9fcb13d5567
Author: Marc Zyngier <maz@kernel.org>

arm64: dts: realtek: Add EL2 virtual timer interrupt

This commit adds the missing EL2 virtual timer interrupt to ARMv8.2-based
Realtek SoCs. It updates rtd16xx.dtsi by adding the fifth timer interrupt
with GIC_PPI 12.

> diff --git a/arch/arm64/boot/dts/realtek/rtd16xx.dtsi b/arch/arm64/boot/dts/realtek/rtd16xx.dtsi
> index 3a7f6e35b7f74..43b13d133c324 100644
> --- a/arch/arm64/boot/dts/realtek/rtd16xx.dtsi
> +++ b/arch/arm64/boot/dts/realtek/rtd16xx.dtsi
> @@ -105,7 +105,8 @@ timer {
>  		interrupts = <GIC_PPI 13 IRQ_TYPE_LEVEL_LOW>,
>  			     <GIC_PPI 14 IRQ_TYPE_LEVEL_LOW>,
>  			     <GIC_PPI 11 IRQ_TYPE_LEVEL_LOW>,
> -			     <GIC_PPI 10 IRQ_TYPE_LEVEL_LOW>;
> +			     <GIC_PPI 10 IRQ_TYPE_LEVEL_LOW>,
> +			     <GIC_PPI 12 IRQ_TYPE_LEVEL_LOW>;
>  	};

Does this update miss another Realtek ARMv8.2+ SoC file?

Looking at arch/arm64/boot/dts/realtek/kent.dtsi (used by RTD1501, RTD1861,
and RTD1920), the fifth timer interrupt is currently defined as
<GIC_PPI 9 IRQ_TYPE_LEVEL_HIGH>.

PPI 9 is the GIC vCPU maintenance interrupt, rather than the EL2 virtual
timer interrupt which should be PPI 12:

arch/arm64/boot/dts/realtek/kent.dtsi:
	timer {
		compatible = "arm,armv8-timer";
		interrupts = <GIC_PPI 13 IRQ_TYPE_LEVEL_LOW>,
			     <GIC_PPI 14 IRQ_TYPE_LEVEL_LOW>,
			     <GIC_PPI 11 IRQ_TYPE_LEVEL_LOW>,
			     <GIC_PPI 10 IRQ_TYPE_LEVEL_LOW>,
			     <GIC_PPI  9 IRQ_TYPE_LEVEL_HIGH>;
	};

Another patch in this series (clocksource/drivers/arm_arch_timer: Default
to EL2 virtual timer when running VHE) changes the driver to use the EL2
virtual timer by default on VHE systems.

If the kernel uses the EL2 virtual timer on these Realtek SoCs, could it
request the wrong interrupt (PPI 9 instead of PPI 12), causing timer
interrupts to not be delivered and resulting in a boot hang regression?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260514150945.3917510-1-maz@kernel.org?part=14